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Home My WebLink AboutSWP2703057CEDAR RIVER SECTION 205 FLOOD DAMAGE REDUCTION STUDY FINAL ENVIRONMENTAL IMPACT STATEMENT U.S. ARMY CORPS OF ENGINEERS SEATTLE DISTRICT AUGUST 1997 1995 Flooding along Cedar River; right bank upstream of the south Boeing bridge. Prepared pursuant to the requirements of, among other laws: the National Environmental Policy Act (NEPA), Coastal Zone Management Act (CZMA); Clean Water Act, including Section 401 and the Section 404(b)(1) guidelines of the Environmental Protection Agency, Section 10 of the Rivers and Harbors Act; Fish and Wildlife Coordination Act; Endangered Species Act; Archaeological and Historic Preservation Act, Washington State Hydraulic Code; the Washington State Environmental Policy Act (SEPA); Indian Treaty Rights. NEPA COVER SHEET/SEPA FACT SHEET This document is a final Environmental Impact Statement pursuant to the National Environmental Policy Act (NEPA) and Washington State Environmental Policy Act (SEPA). Project Name: Cedar River Section 205 Flood Damage Reduction Study Project Location: The project is along the lower 1.25 miles (2000 m) of the Cedar River in Renton, King County, Washington. This portion of the river is entirely contained in an artificial channel constructed in 1911 by Commercial Waterway District No. 2. Prior to construction of this channel into Lake Washington, the Cedar River flowed into the Black River and thence into Elliott Bay. Proponents and Lead Agencies: The project proponents and lead agencies are the U.S. Army Corps of Engineers, Seattle District and the City of Renton. The Corps of Engineers is the NEPA lead agency, and the City of Renton is the SEPA lead agency. Proposed Action & Alternatives: The basic project purpose is to provide 100 year flood control along the lower 1.25 miles (2000 m) of the Cedar River in Renton. Additional project objectives include: preventing damage to the south Boeing bridge from high water and logs or other debris; reducing the threat to public safety from flood waters inundating the Cedar River Trail; and providing an environmentally sound project. The alternatives considered are: • No Action -- do not pursue a flood control project along the lower 1.25 miles (2000 m) of the Cedar River. Allow sediment to continue to accumulate in this reach of the river and delta at a rate of 0.1-1.0 feet/year. Flood damages would continue to worsen until the river could not carry even normal fall and winter flows. Existing Channel -- construction of a levee system along both banks of the river up to rivermile (RM) 1.6 (2560 m) with only minimal initial dredging to even out the channel depth. The channel would require maintenance dredging approximately every 3 years to maintain 100 year capacity. The south Boeing bridge would be modified to be lifted hydraulically during flood events, thus removing a critical flow restriction and avoiding damage from high water and debris. The Logan Avenue and next four bridges upstream would also require modification to avoid inducing flooding upstream. • Minimum Dredge -- the channel would be dredged to an average depth of 4 feet (1.2 m) below the existing river bottom. Levees would also be constructed along both banks up to RM 1.25 (2000 m). The channel would require maintenance dredging approximately every 3 years to maintain 100 year capacity. The south Boeing bridge would be modified to be lifted hydraulically during flood events, thus removing a critical flow restriction and avoiding damage from high water and debris. • Moderate Dredge -- the channel would be dredged to an average depth of 6 feet (1.8 m) below the existing river bottom. Levees would also be constructed along both banks up to RM 1.25 (2000 m). The channel would require maintenance dredging approximately every 3 years to maintain 100 year capacity. The south Boeing bridge would be modified to be lifted hydraulically during flood events, thus removing a critical flow restriction and avoiding damage from high water and debris. • Deep Dredge -- the channel would be dredged to an average depth of 10 feet (3 m) below the existing river bottom. Levees would also be constructed along both banks up to RM 1.25 (2000 m). The channel would require maintenance dredging approximately every 3 years to maintain 100 year capacity. The south Boeing bridge would be modified to be hydraulically jacked during flood events, thus removing a critical flow restriction and avoiding damage from high water and debris. Responsible Officials: Colonel Donald T. Wynn District Engineer, Seattle District U.S. Army Corps of Engineers 4735 East Marginal Way South P.O. Box 3755 Seattle, WA 98124-2255 Mayor Jesse Tanner City of Renton 200 Mill Avenue South Renton, WA 98055 Contact For Further Information: Merri Martz Environmental Resources Section U.S. Army Corps of Engineers P.O. Box 3755 Seattle, WA 98124-2255 (206) 764-3624 Licenses. Permits and Other The following permits and approvals will be required. Required Approvals: •Section 10/404 Equivalency Determination •Water Quality Certification •Consistency with Coastal Zone Management Act •Hydraulic Project Approval *City of Renton Substantial Development Permit/Shoreline Permit •City of Renton Grading Permit Authors and Contributors: (all are Seattle District, U.S. Army Corps of Engineers employees) Principal Author: Merri S. Martz Wetland and Stream Ecologist Contributors: Kenneth R. Brunner Wildlife Biologist Bird and Wildlife Surveys Gail C. Celmer Archaeologist Cultural Resources and Indian Treaty Rights Frederick A. Goetz Fisheries Biologist Fisheries Technical Review Kathleen S. Kunz Wetland Scientist Technical Review Cyrus M. McNeely Biologist and NEPA Compliance Technical Review Location of Public Viewing Copies of this final EIS: U.S. Army Corps of Engineers, Seattle District District Library 2nd Floor, Federal Center South 4735 East Marginal Way South (Seattle) Renton Public Library 100 Mill Avenue, S. Renton, Washington University of Washington (Seattle) Government Publications Suzzallo Library, 1st Floor How to Request Copies of this EIS: Call Merri Martz at (206) 764-3624 4_, - -_ - __ I�i i I c • - - l ` - - -Mt '4.- L_ •fir, J t fit 97k A LF : _-` Aj — —_�` - �' = I • ��'�—_ = __ � `�iJ _r.�ti -fir— — -��c �� -� z'y < - T ~ — _ iE 77 �-- -_ _ - _ =-I i-�� ` _— - _ Ana~- —_ _ � - •� — _ •�_� y IE TABLE OF CONTENTS Title Page NEPA Cover Sheet/SEPA Fact Sheet, including List of Preparers Table of Contents ExecutiveSummary ......................................................................................................... i Section 1. Purpose and Need for the Action............................................................. 1 1.1 Introduction................................................................................................ 1 1.2 Study Authority........................................................................................... 1 1.3 Flooding History.........................................................................................2 1.4 Need for Flood and Sediment Control....................................................... 3 1.5 Project Purpose......................................................................................... 4 1.6 Agency and Public Issues.......................................................................... 4 Section2: Alternatives.............................................................................................. 11 2.1 Plans Eliminated from Detailed Study ...................................................... 11 2.1.1 Upstream Sediment Control........................................................... 11 2.1.2 Upstream Levee Removal............................................................. 11 2.1.3 Widening the River Channel in the Project Reach ......................... 12 2.1.4 Modifying the Boeing Bridges to be Raised During Flood Events.. 12 2.1.5 Nonstructural Floodproofing of Building in the Project Area .......... 12 2.1.6 Dredging the Lower Mile to Historical Depths ................................ 13 2.1.7 Levee Placement Along the Lower Mile ......................................... 13 2.1.8 Sediment Trap............................................................................... 13 2.2 Alternatives Evaluated in this EIS............................................................ 14 2.2.1 No Action....................................................................................... 14 2.2.2 Existing Channel Depth With Levees and Modifications to the South Boeing Bridge......................................................................14 2.2.3 Minimum Dredging Combined With Levees and Modifications to the South Boeing Bridge (Preferred Alternative) .....................15 2.2.4 Moderate Dredging Combined With Levees and Modifications to the South Boeing Bridge............................................................ 15 2.2.5 Deep Dredging Combined With Levees and Modifications to the South Boeing Bridge............................................................ 16 2.2.6 Possible Dredging Methods for All Dredging Alternatives .............. 16 2.2.6.1 Barge Mounted Clamshell or Dragline .............................. 16 2.2.6.2 Hydraulic Suction Dredging of Fine Materials...................26 2.2.6.3 Divert River Flow for Removal of Generally Dry Material .26 2.2.7 Disposal Site for Dredged Material ................................................ 26 Section 3: Affected Environment..............................................................................29 3.1 Geology/Soils/Sediments.........................................................................29 3.1.1 Geology......................................................................................... 29 3.1.2 Soils/Topography...........................................................................29 3.1.3 Sediments......................................................................................30 3.1.4 Floodplain Management................................................................ 31 3.2 Water....................................................................................................... 31 3.2.1 Surface Water................................................................................ 31 3.2.2 Groundwater..................................................................................32 3.2.3 Contribution of Tributaries Below Landsburg................................. 32 3.2.4 Water Quality................................................................................. 33 3.2.5 Wetlands........................................................................................34 3.3 Habitat..................................................................................................... 34 3.4 Fish.......................................................................................................... 36 3.4.1 Salmon...........................................................................................36 3.4.2 Longfin Smelt.................................................................................40 3.4.3 Other Species................................................................................ 41 3.5 Aquatic Invertebrates............................................................................... 42 3.6 Wildlife..................................................................................................... 43 3.7 Threatened and Endangered Species ..................................................... 43 3.8 Vegetation................................................................................................45 3.9 Cultural Resources.................................................................................. 46 3.10 Land Use/Recreation/Public Use............................................................. 46 3.11 Transportation..........................................................................................47 3.12 Air/Noise/Light..........................................................................................48 3.13 Aesthetics................................................................................................ 48 3.14 Public Services/Utilities/Energy................................................................ 48 3.15 Public Health and Safety..........................................................................48 Section 4: Environmental Impacts............................................................................ 50 4.1 Geology/Sediments/Soils/Floodplains..................................................... 50 4.1.1 No Action Alternative..................................................................... 50 4.1.2 Existing Channel Alternative.......................................................... 50 4.1.3 Minimal Dredge Alternative............................................................51 4.1.4 Moderate Dredge Alternative......................................................... 51 4.1.5 Deep Dredge Alternative................................................................ 52 4.2 Water and Water Quality.......................................................................... 52 4.2.1 No Action Alternative..................................................................... 53 4.2.2 Existing Channel Alternative.......................................................... 53 4.2.3 Minimal Dredge Alternative............................................................ 54 4.2.4 Moderate Dredge Alternative......................................................... 54 4.2.5 Deep Dredge Alternative................................................................ 54 4.3 Fish.......................................................................................................... 54 4.3.1 Sockeye Salmon............................................................................54 4.3.1.1 No Action Alternative........................................................ 54 4.3.1.2 Existing Channel Alternative ............................................. 55 4.3.1.3 Minimal Dredge Alternative ............................................... 55 4.3.1.4 Moderate Dredge Alternative ............................................ 56 4.3.1.5 Deep Dredge Alternative................................................... 57 4.3.2 Chinook Salmon............................................................................. 57 4.3.2.1 No Action Alternative........................................................ 57 4.3.2.2 Existing Channel Alternative ............................................. 58 4.3.2.3 Minimal Dredge Alternative ............................................... 58 4.3.2.4 Moderate Dredge Alternative ............................................ 58 4.3.2.5 Deep Dredge Alternative................................................... 59 4.3.3 Coho Salmon................................................................................. 59 4.3.3.1 No Action Alternative........................................................ 59 4.3.3.2 Existing Channel Alternative.............................................59 4.3.3.3 Minimal Dredge Alternative ............................................... 60 4.3.3.4 Moderate Dredge Alternative ............................................ 60 4.3.3.5 Deep Dredge Alternative................................................... 60 4.3.4 Steelhead Trout............................................................................. 61 4.3.4.1 No Action Alternative........................................................ 61 4.3.4.2 Existing Channel Alternative ............................................. 61 4.3.4.3 Minimal Dredge Alternative ............................................... 61 4.3.4.4 Moderate Dredge Alternative ............................................ 62 4.3.4.5 Deep Dredge Alternative................................................... 62 4.3.5 Sea -Run Cutthroat Trout............................................................... 62 4.3.6 Resident Cutthroat and Rainbow Trout .......................................... 62 4.3.6.1 No Action Alternative........................................................ 62 4.3.6.2 Existing Channel Alternative.............................................63 4.3.6.3 Minimal Dredge Alternative ............................................... 63 4.3.6.4 Moderate Dredge Alternative ............................................ 63 4.3.6.5 Deep Dredge Alternative................................................... 63 4.3.7 Longfin Smelt.................................................................................64 4.3.7.1 No Action Alternative........................................................ 64 4.3.7.2 Existing Channel Alternative ............................................. 64 4.3.7.3 Minimal Dredge Alternative ............................................... 64 4.3.7.4 Moderate Dredge Alternative ............................................ 65 4.3.7.5 Deep Dredge Alternative................................................... 65 4.3.8 Sculpins......................................................................................... 65 4.3.8.1 No Action Alternative........................................................ 65 4.3.8.2 Existing Channel Alternative.............................................65 4.3.8.3 Minimal Dredge Alternative...............................................66 4.3.8.4 Moderate Dredge Alternative ............................................ 66 4.3.8.5 Deep Dredge Alternative................................................... 67 4.3.9 Other Native Fish Species............................................................. 67 4.3.9.1 No Action Alternative........................................................ 67 4.3.9.2 Existing Channel Alternative ............................................. 68 4.3.9.3 Minimal Dredge Alternative ............................................... 68 4.3.9.4 Moderate Dredge Alternative ............................................ 68 4.3.9.5 Deep Dredge Alternative................................................... 69 4.3.10 Non -Native Fish Species............................................................. 69 4.3.10.1 No Action Alternative...................................................... 69 4.3.10.2 Existing Channel Alternative ........................................... 70 4.3.10.3 Minimal Dredge Alternative.............................................70 4.3.10.4 Moderate Dredge Alternative .......................................... 70 4.3.10.5 Deep Dredge Alternative ................................................. 70 4.4 Aquatic Invertebrates...............................................................................71 4.4.1 No Action Alternative..................................................................... 71 4.4.2 Existing Channel Alternative.......................................................... 71 4.4.3 Minimal Dredge Altemative............................................................ 71 4.4.4 Moderate Dredge Alternative.........................................................72 4.4.5 Deep Dredge Alternative................................................................ 72 4.5 Wildlife..................................................................................................... 72 4.5.1 No Action Alternative..................................................................... 72 4.5.2 All Dredging Alternatives................................................................ 73 4.6 Threatened and Endangered Species.....................................................74 4.6.1 Bald Eagle...................................................................................... 74 4.6.1.1 No Action Alternative........................................................ 74 4.6.1.2 All Dredging Alternatives................................................... 74 4.6.2 Candidate Salmon Species............................................................ 74 4.6.3 Species of Concern: Northwestern Pond Turtle ............................ 74 4.7 Vegetation................................................................................................74 4.7.1 No Action Alternative..................................................................... 74 4.7.2 All Dredging Alternatives................................................................ 75 4.8 Cultural Resources.................................................................................. 75 4.9 Land Use/Recreation/Public Use............................................................. 75 4.9.1 No Action Alternative..................................................................... 75 4.9.2 All Dredging Alternatives................................................................ 76 4.10 Transportation..........................................................................................76 4.10.1 No Action Alternative................................................................... 76 4.10.2 Dredging Alternatives................................................................... 76 4.10.2.1 Existing Channel Alternative...........................................77 4.10.2.2 Minimal Dredge Alternative ............................................. 77 4.10.2.3 Moderate Dredge Alternative .......................................... 77 4.10.2.4 Deep Dredge Alternative ................................................. 77 4.11 Air/Noise/Light..........................................................................................78 4.11.1 No Action Alternative................................................................... 78 4.11.2 All Dredging Alternatives..............................................................78 4.12 Aesthetics................................................................................................ 78 4.12.1 No Action Alternative................................................................... 78 4.12.2 All Dredging Alternatives.............................................................. 78 4.13 Public Services/Utilities/Energy................................................................ 79 4.13.1 No Action Alternative................................................................... 79 4.13.2 All Dredging Alternatives.............................................................. 79 4.14 Public Health and Safety..........................................................................79 4.14.1 No Action Alternative................................................................... 79 4.14.2 All Dredging Alternatives.............................................................. 79 4.15 Likely Irretrievable Commitment of Resources........................................79 4.15.1 No Action Alternative................................................................... 79 4.15.2 All Dredging Alternatives..............................................................79 4.16 Aquatic Ecosystem Interactions...............................................................80 4.16.1 No Action Alternative................................................................... 80 4.16.2 Dredging Alternatives................................................................... 80 4.17 Cumulative Impacts................................................................................. 80 4.17.1 No Action Alternative................................................................... 80 4.17.2 All Dredging Alternatives.............................................................. 81 Section 5: Mitigation and Monitoring Plan.............................................................. 84 5.1 Avoidance of Adverse Impacts................................................................ 84 5.2 Minimization of Adverse Impacts............................................................. 84 5.3 Rectification of Adverse Impacts..............................................................84 5.4 Unavoidable Adverse Impacts................................................................. 85 5.5 Compensatory Mitigation for Unavoidable Impacts (Preferred Alt.)......... 86 5.6 Monitoring Plan........................................................................................87 5.7 Impacts and Mitigation for Moderate Dredge Alternative ......................... 88 Section 6: Status of Compliance with Applicable Laws and Regulations............ 94 References.................................................................................................................97 Glossary.................................................................................................................99 Appendices A: Comments Received on Draft EIS With Responses From the Corps B: U.S. Fish & Wildlife Service, Fish and Wildlife Coordination Act Report, With Responses by the Corps to Recommendations in the Report C: Distribution of Draft EIS Attendance List for DEIS Workshop Workshop Agenda Memorandum for Record of Workshop Proceedings LIST OF FIGURES FIGURE1: Vicinity Map................................................................................................. 6 FIGURE 2: Cedar River Basin Map................................................................................7 FIGURE 3: Lower Cedar River....................................................................................... 8 FIGURE 4: Anadromous Fish Access in Cedar River Basin .......................................... 9 FIGURE 5: Historical Route of the Cedar River/Black River ........................................ 10 FIGURE 6: Dredge Profiles for All Action Alternatives ................................................. 17 FIGURE 7: Levee/Floodwall Footprint for Preferred Alternative .................................. 18 FIGURE 8: Typical Levee Sections..............................................................................23 FIGURE 9: Typical Floodwall Sections.........................................................................24 FIGURE 10: Barge Mounted Clamshell Dredge...........................................................25 FIGURE11: Excavator.................................................................................................25 FIGURE 12: Hydraulic Pipeline Cutterhead Dredge.....................................................26 FIGURE 13: Location of Narco Site (Disposal Site) ..................................................... 28 FIGURE 14: Cedar Basin Wetlands............................................................................. 35 FIGURE 15: Proposed Haul Route for Dredged Material ............................................. 83 FIGURE16: Mitigation Plan......................................................................................... 90 FIGURE 17: Upstream Mitigation Site..........................................................................92 FIGURE 18: Side Channel Plan...................................................................................93 LIST OF TABLES TABLE A: Summary of Impacts to Each Element of the Environment ..........................vii TABLE 1: Cedar River Basin Fishes and Status.......................................................... 37 TABLE 2: Number of Sockeye Redds Observed in the Lower 1.25 Miles .................... 39 TABLE 3: Birds Observed in Vicinity of Lower Cedar River ......................................... 44 TABLE 4: Summary of Impacts.................................................................................... 82 TABLE 5: Summary of Consistency of the Preferred Alternative with Applicable Laws andRegulations............................................................................................................ 95 TM 7 W- Tor-- -Tr-T-Mw 'AF ;r 11 4X-A- -t, IS OL ;r Jo rip % tv % 4? V, �.T L m7T V r -= Y— -F. L I - . —t ogre V, Lt —46 1 A eat L jr 9 w 6-- UXIL EXECUTIVE SUMMARY SA AUTHORITY AND JURISDICTION This final Environmental Impact Statement was prepared pursuant to the National Environmental Policy Act (NEPA) and the Washington State Environmental Policy Act (SEPA) to support federal, state, and local decision -making processes for the U.S. Army Corps of Engineers proposed Section 205 Flood Control Project on the lower Cedar River in Renton, Washington. Section 205 of the 1948 Flood Control Act (as amended) provides for the U.S. Army Corps of Engineers to enter into a local/federal cost -shared agreement to plan and construct small flood control projects (less than $5 million total federal cost). It was determined that an EIS was warranted for this proposed project because of the significant environmental resources present in and around the lower Cedar River. The level of controversy surrounding a proposed flood control project was also very high early in the planning process. The Seattle District, U.S. Army Corps of Engineers (Corps) is NEPA lead agency for this project. The Corps is the joint project proponent with the City of Renton, as local sponsor. The Corps of Engineers has permitting authority over the excavation or placement of material in waters of the United States. NEPA requires that environmental consequences of the total project be evaluated as part of the decision - making process. The City of Renton is lead agency under SEPA. The City of Renton is a joint project proponent and also has jurisdiction under the Shoreline Management Act for construction activities occurring in shoreline areas within City jurisdiction. S.2 PROJECT LOCATION The proposed Section 205 Flood Control Project is located in the lower 1.25 miles (2000 m) of the Cedar River in Renton, Washington. This portion of the river is an artificially constructed channel built in 1912 by Commercial Waterway District Number 2. Prior to 1912, the Cedar River flowed into the Black River and on into the Duwamish River to Elliott Bay. The diversion of the Cedar River into Lake Washington occurred at approximately the same time that the Corps constructed the Lake Washington Ship Canal and lowered Lake Washington by 9 feet (2.7 meters). Currently, the Cedar River flows into Lake Washington at the extreme southern end of the lake (see Figure 1). Immediately adjacent to the lower river is the Renton Municipal Airport (left bank facing downstream) and the Cedar River Trail Park (City of Renton) and the Boeing Company (right bank). Four bridges (2 city roads and 2 privately owned by Boeing) cross the Cedar River in the lower 1.25 miles (2000 m). S3. PROJECT HISTORY AND BACKGROUND Since the Cedar River was diverted into Lake Washington in 1912, the river has been periodically dredged to maintain a flood capacity of approximately a 20 year flood (original channel was designed to be 10 feet [3.3 m] deep). The Commercial Waterway District No. 2 dredged the river and delta approximately every 10 years until 1957, when the City of Renton (hereafter, City) assumed responsibility for maintaining the channel. The City continued dredging the channel and delta until 1983. Stoneway Gravel mined the channel upstream of RM 1.5 (2.4 km) for gravel until the early 1970s, removing 10,000-50,000 CY of material annually. Since 1983, the channel has not been maintained. The City did not always maintain the channel to the original depth, after the north Boeing bridge was built across the mouth of the river in 1962 greatly restricting access for subsequent dredging. Flooding in the Cedar River, similar to other western Washington rivers, typically occurs in the months from October through April from warm maritime rainstorms with heavy precipitation, often accompanied by extensive snowmelt in the Cascades. In November 1990, a series of heavy rainstorms occurred in western Washington, causing widespread flooding. The Cedar River reached the highest flood level recorded at Renton since 1945 (10,200 cfs). This was estimated by the Corps to be a 50 year flood. Depths of flooding at Boeing and the airport were 3-4 feet (approx. 1 m). Property damage adjacent to the lower Cedar River during the 1990 flood were estimated to be $8 million. Flooding was exacerbated by the accumulation of sediment in the lower Cedar River. Sediment has continued to accumulate in the lower few miles of the Cedar River since 1990, which continues to increase the risk of flooding. Sediment is deposited readily in the lower Cedar River because the gradient is very low and sediment readily deposits when water velocities reduce in this area. Sediment modeling indicates that the channel has been filling in at a rate of 0.1-1.0 feet (0.03-0.3 m) per year on average. The City requested Federal assistance in reducing flood damages in 1993. The Boeing Company also supported the Federal study. The Corps conducted an initial appraisal under Section 205 and determined that there was a federal interest in providing flood control in Renton. The Corps and the City entered into a Federal Cost Sharing Agreement for the feasibility phase of the study, which is nearing completion. S4. PURPOSE AND NEED FOR THE PROJECT This project is needed to control flooding in the lower 1.25 miles (2000 m) of the Cedar River, in Renton, Washington. Current river channel capacity is reduced to the point that the left bank (facing downstream) overflows at 2200 cfs (approximately a 1.6 year event) and the right bank (facing downstream) overflows at 8000 cfs (approximately a 23 year event). The sediment load coming down the river is very high; it is calculated that in less than 20 years, the Cedar River will no longer contain moderate winter flows and will likely break out of the channel, onto the airport. The reduced channel capacity also poses a serious threat to fishery resources. When the channel can no longer contain even normal winter flows, there would likely be significant numbers of fish stranded and the river would likely be nearly inaccessible to anadromous fish. Various pollutants from the airport and Boeing would also likely be frequently washed, or leached, into the river and Lake Washington. S5. ALTERNATIVES Several alternatives were evaluated early in the planning process, but discarded because they did not meet the project objective of providing 100 year flood control in the City of Renton. Alternatives that did meet the project objective were evaluated in detail in this EIS: The no action alternative and four dredging/levee alternatives were evaluated in detail in the draft EIS because it was not possible to identify the clearly better alternative until late in the planning process. In this final EIS, the Corps has selected the minimum dredging alternative as the preferred alternative based upon environmental and economic considerations. The existing channel depth alternative is the least environmentally damaging alternative; however, it was not chosen as the preferred alternative because the cost of this project is higher than the minimal or moderate dredging alternatives since it induces flooding upstream and would require additional levees and modifications to several bridges upstream. It also causes an unreasonable economic burden on Boeing because their bridge would have to be raised for several days at all flows above a 10 year flood. ALTERNATIVES ELIMINATED FROM DETAILED ANALYSIS • Upstream Sediment Control • Upstream Levee Removal • Widening the river Channel in the Project Reach • Modifying the Boeing Bridges (Not in combination with other measures) • Nonstructural Floodproofing of Building in the Project Area • Dredging the Lower Mile to Historical Depths (Not in combination) • Levee Placement Along the Lower Mile (Not in combination) Sediment Trap ALTERNATIVES EVALUATED IN THIS EIS No Action This alternative would take no action to control flooding in Renton. Sediment would continue to accumulate in the project reach, further reducing flood conveyance. Eventually, the river would typically flow across the airport. Existing Channel Depth with Levees and Modifications to the South Boeing Bridge This alternative would require limited dredging, of approximately 31,000 CY, to even out the channel bottom to the existing thalweg (deepest channel area) depth. Levees and/or floodwalls would be placed along the right bank from 1-405 (-1.6 miles, 2.56 km) to the mouth and on the left bank from 1-405 to approximately 1000 feet (330 m) upstream of the mouth. A low berm (to comply with FAA regulations) would be placed on the left bank from 1000 feet (330 m) upstream down to the mouth. Bank protection (rock) would be placed below ordinary high water on the left bank below Logan Avenue for approximately 400 linear feet (120 meters). The bridges at Logan, Williams and Wells Avenue and Bronson and Hauser Way would require modifications to raise them above the 100 year flood level in order to avoid inducing flooding upstream of Bronson Way. The south Boeing bridge would be modified to be hydraulically jacked above the 100 year flood level during flood events, and the levee openings at the bridge would be closed using rigid movable structures. The channel would require periodic maintenance dredging to maintain the existing channel depth. This maintenance dredging would occur, on average, every three years and would require the removal of 114,000 CY of material at each maintenance cycle. Construction of this project would cost approximately $10.9 million. Preferred Alternative: Minimum Dredaing with Levees and Modifications to the South Boeina Bridae This alternative would require dredging an average of four feet (1.2 m) of sediment from the channel from the Cedar River mouth up to Logan Avenue and then sloping the dredged depth up to zero to meet the existing gradient at Williams Avenue (800 feet [240 m] upstream of Logan). Levees or floodwalls would be required on the right bank from Williams Avenue (RM 1.25, 2000 km) down to the mouth and on the left bank from Williams Avenue down to 1000 feet (330 m) upstream of the mouth. A low berm would be constructed on the left bank from 1000 feet down to the mouth. Bank protection and the south Boeing bridge would be constructed/modified as described above for the existing channel alternative. The channel would require periodic maintenance dredging to maintain the existing channel depth. This maintenance dredging would happen every three years, conservatively on average, and would require the removal of 171,000 CY of material at each maintenance cycle. Construction of this project would cost approximately $8.3 million. Moderate Dredaina with Levees and Modifications to the South Boeing Bridae This alternative would require dredging an average of six feet (1.8 m) of sediment from the channel from the Cedar River mouth up to Logan Avenue and then sloping the dredged depth up to zero to meet the existing gradient at Williams Avenue (800 feet [240 m] upstream of Logan). Levees, floodwalls, bank protection and the south Boeing bridge would be constructed/modified as described above for the preferred alternative. The channel would require periodic maintenance dredging to maintain the existing channel depth. This maintenance dredging would happen every three years, iv conservatively on average, and would require the removal of 176,000 CY of material at each maintenance cycle. Construction of this project would cost approximately $8.5 million. Deep Dredging with Levees and Modifications to the South Boeing Bridge This alternative would require dredging an average of ten feet (3 m) of sediment from the channel from the Cedar River mouth up to Logan Avenue and then sloping the dredged depth up to zero to meet the existing gradient above Wells Avenue (1200 feet [370 m] upstream of Logan). Levees, floodwalls, bank protection and the south Boeing bridge would be constructed/modified as described above for the preferred alternative. The channel would require periodic maintenance dredging to maintain the existing channel depth. This maintenance dredging would happen every three years, conservatively on average, and would require the removal of 185,000 CY of material at each maintenance cycle. Construction of this project would cost approximately $9.3 million. Potential Dredging Methods and Disposal Site for Preferred Alternative Barge Mounted Clamshell or Dragline Dredge A barge mounted clamshell dredge or dragline would likely be utilized in the lower 3300 feet (1000 m) of the river with 4 foot (preferred) alternative, because the water depth would be sufficient to float a barge if dredging commenced at the downstream end and proceeded upstream while deepening the channel. The use of a barge would minimize conflicts with airport traffic. Upstream of 3300 feet (1000 m), another dredging method would be utilized, see below. With either barge -mounted alternative, the dredged material will likely be placed in a dewatering area in the park, and then rehandled into trucks for transportation to the sediment storage site upstream of 1-405 (see Figure 13). Barge Mounted Hydraulic Suction Dredge In the lower 3300 feet (1000 m) of the river, it may also be possible to utilize a hydraulic suction dredge which would pump the material and associated water to a barge out in Lake Washington or to the dewatering area in the park. Use of Coffer Dams and a Gravel Berm to Divert the River During Dredging The most likely method for dredging upstream of 3300 feet (1000 m) from the mouth, is to divert the river channel from one bank to the other in order to dredge in the dry half of the channel with a front end loader or excavator. A gravel berm would be constructed in the center of the river from gravel bar material and all trucks/excavators would drive in on the gravel berm. An inflatable, or other type of, coffer dam would be v placed upstream and downstream of the dredging area to divert the flow away from the dredging area and prevent runoff from the dredging site into the river. Disposal Area The disposal area, known as the Narco site, is currently owned by the City of Renton. The site is immediately upstream of 1-405 on the left bank (across from Carco Theater). This site was a former industrial site with concrete or asphalt paving over most of the site. No wetlands are located in the disposal area. The material will be brought there by trucks (see Figure 16) and stored. The site is sufficiently large to contain the dredged material piled several feet high. The City of Renton may pursue direct sale of the material to private entities, but that activity is not addressed in this EIS. S6. ENVIRONMENTAL IMPACTS AND PROPOSED MITIGATION MEASURES The Corps determined that an EIS was warranted early in the planning process and published a Notice of Intent to Prepare and EIS in the Federal Register on 1 June 1995. Reasons for deciding to prepare an EIS included a high level of controversy amongst resource agencies at the federal and state level, and Indian tribes, regarding the proposed project, and the importance of the Cedar River to the Lake Washington aquatic ecosystem, including the locally important sockeye salmon run. Evaluation of impacts in the draft EIS demonstrated that some of the potential environmental impacts identified during scoping as "significant"' turned out to be of lesser impact, whereas, impacts on elements such as traffic and noise may be more significant than originally expected, at least during construction. Table A shows a summary matrix of all environmental impacts and their relative significance. The general impacts identified as significant in the draft EIS included: • urban impacts, such as traffic and transportation, and recreation, all relating to construction and maintenance activities. loss of aquatic habitat after project construction, including long-term impacts from frequent disturbances during maintenance activities. During the public review period for the draft EIS, most commentors concurred with the preferred alternative and the identified impacts (see Appenix A). However, one significant impact was not included in the draft EIS which is now included in this final EIS: increased predation on chinook fry which will likely result in reduced survival of chinook. ' The expectation of "significant" adverse impacts is a trigger for whether or not an EIS is required, per NEPA. W Table A. Summary of Impacts to Each Element of the Environment (symbols described below) Element of the Environment No Action Existing Channel Minimal Dredge Moderate Dredge Deep Dredge Construction & Maintenance Geology/Soils/Sedim ents NC NC Water/Water Quality NC Sockeye Salmon NC -- --- NA Chinook Salmon NC - NA Coho Salmon NC NC NC NC NA Steelhead Trout NC NC NC - NC Resident Trout NC NC NC NC NC Lon fin Smelt NC + + + NA Prickly Scul in NC + + ++ Coastrange & Torrent Scul ins + NC - Mountain Whitefish NC NC NC + + NC Northern S uawfish NC NC + + NC Lar escale Suckers NC NC + + NC Peamouth Chub NC NC + + NC Three -spine Stickleback NC NC + + NC Brook Lamprey NC Non -Native Fish NC + + + NC Aquatic Invertebrate Diversity & Abundance + NC Wildlife NC + + + + Riparian Oriented Birds NC + + + + NC Open Water/Ground Birds NC NC Bald Eagles NC NC NC NC NC NC Riparian Vegetation NC + + + + NC Aquatic Vegetation NC + + ++ Cultural Resources NC NC NC NC NC NC Land Use/Recreation NC NC NC NC Transportation + + + + Air/Noise/Light NC NC NC NC NC --- Aesthetics NC NC NC NC Public Services NC + + + NC Public Health/Safety NC + + + slight negative impact or change from existing condition -- moderate negative impact or change from existing condition — large negative impact or change from existing condition + slight positive impact ++ moderate positive impact NC no change or negligible change NA not applicable VII Probable Significant Unavoidable Adverse Impacts From the Preferred Alternative • Very frequent truck traffic on City public roads and Boeing private roads during the two month in -water construction window from approximately June 15 - August 31. For the minimal dredge alternative, 158,000 CY of river bed material will be dredged and loaded into trucks which can haul 10 or 20 CY of material each. This will require a minimum of 7900 truck trips each way from the Cedar River to the sediment storage site at the former Narco industrial location just upstream of 1-405 and back to the river. • Loss of poor and moderate quality adult salmon (sockeye, chinook, coho and/or steelhead) spawning area up to 3300 feet (1000 m) from the mouth, because of the increase in lake backwater area from the current 1000 feet (300 m) from the mouth. A maximum of 235 redds have been observed in this area during the spawning season (1996 very high year), so effective loss of habitat is estimated to be 2560-3840 ft2 (230- 352 m2, assuming 1 - 1.5 m2/redd). • Likely increased predation on sockeye and chinook fry in area of increased lake backwater (maximum of 253,000 ft2, 5.8 acres or 23,230 m2). Prickly sculpin and other resident fish such as trout will have an increase of habitat. It is unclear to what extent their populations may increase, due to the disturbance from frequent maintenance dredging. However, it is expected that sockeye and chinook fry survival will be reduced as a result of this project. • Periodic loss of 45,000 ft2 (4100 m2) of bank scour pool habitat which is utilized by adult salmon, juvenile salmon/trout, and resident trout for holding and refuge. The increase in lake backwater will provide 253,000 ft2 (5.8 acres or 23,230 m2) of additional slower velocity habitat, but will not provide holding upstream of 3300 feet (1000 m) from the mouth. Immediately after dredging, this habitat will be lost, due to the trapezoidal shape of the dredged channel. It is expected that in the first winter season after dredging, the channel will readjust itself and recreate some of the bank scour pool habitat. • Loss of 253,000 ft2 (5.8 acres or 23,230 m2) of coastrange and torrent sculpin habitat due to lake backwater increase; this habitat will now be suitable for prickly sculpin and provide an equal increase in habitat for prickly sculpin, as described above under increase in sockeye and chinook fry predators. • Probable decline in aquatic invertebrate diversity and abundance due to frequent maintenance dredging which will remove invertebrates during their maximum growth period. Also, the increase in lake backwater will reduce habitat for organisms that prefer higher velocities while increasing habitat for organisms that prefer lower velocities. Species which prefer higher velocities are typically preferred by salmon for feeding. ME • Possible decline in brook lamprey population due to frequent maintenance dredging. Proposed Mitigation Measures To compensate for unavoidable adverse impacts, the Corps proposes to: • Restrict truck traffic on City roads to the designated 75 day construction period. All roads, park lands, or other facilities damaged during construction will be replaced in - kind. Minimize spillage from trucks onto roadways by lining the trucks or other measures, avoiding heavy traffic on Rainier Avenue. Removing some material by barge rather than truck will be investigated during plans and specifications to further reduce these impacts. • Replace spawning habitat, adult holding habitat and compensate for likely increased predation on sockeye fry by creating a groundwater fed pond and side channel upstream of the project area (see Figure 18) at approximately RM 5 (8 km). This channel would have approximately 9000 ft2 (826 m2) of moderate velocity habitat suitable for spawning except during high flooding events (>6300 cfs). Native trees and shrubs will be planted on 2 acres surrounding the pond/side channel to provide shading, cover and insect production as well as to reduce flood scouring. • Offset likely increase in predation on chinook fry by either: 1) placing large woody debris for 500 linear feet along the mainstem Cedar adjacent to the upstream groundwater fed channel site. This will provide better habitat for chinook rearing during their transit down river and will offset negative effects in the lower river. Additionally, this will provide increased protection to the groundwater channel site. Or, 2) revegetating and placing LWD at the Maplewood Golf Course levee to provide cover and rearing habitat in the mainstem to offset negative effects in the lower river. • Offset probable decline in aquatic invertebrate populations by providing an alternative source of nutrients and insect production by planting riparian vegetation. Riparian vegetation consisting of native species such as willows, mock orange, western hemlock, salmonberry, currants, etc. will be planted in a 15 foot wide buffer along the right bank (park) below the south Boeing bridge and willows will be planted into the left bank (airport). These plantings will also replace vegetation lost on the left bank during construction. The river is expected to scour small pools along the vegetated bank between dredge cycles that will provide habitat similar to the existing bank scour pool habitat. S.7 PUBLIC INVOLVEMENT The public involvement process for the Cedar River 205 feasibility study began with the publication of the Notice of Intent to Publish an EIS, which was printed in the Federal Register on 1 June 1995. The scoping period was from 1 June until 30 June 1995. An IM agency scoping meeting was held on 24 May 1995, followed by a public scoping meeting held on 13 June 1995. Notices to the EIS mailing list were delivered in September 1995 to indicate that the schedule for the EIS had been delayed and the draft EIS would not be published until November 1996 at the earliest. Coordination with the resource agencies and tribes has continued during the time period since scoping. The draft EIS had a 45 day comment period and a public workshop was held on 29 April 1997. No requests were received for a public hearing. Comments were received at the public workshop and a total of eleven written comment letters from agencies or individual persons were received. These letters as well as a comment with response section are enclosed as Appendix A to this final EIS. The public review period revealed that there was no significant controversy about the proposed project and preferred alternative. In general, most agencies and individuals support the project. There were concerns about impacts to chinook salmon, especially in light of their potential listing as an endangered species. There were also concerns about the ability of the proposed upstream mitigation site to function correctly. The draft EIS did not have sufficient information on the upstream mitigation site to fully describe its functioning. In several sections, clarifying information has been added to reduce the confusion which some commentors had about statements made in the draft EIS. Details on the upstream mitigation site and subsequent monitoring of mitigation elements will continue to be refined during the next phase of study: Plans and Specifications. Interested parties and agencies will continue to be involved in the final design of the mitigation. The local sponsor is required to obtain the following permits prior to construction of the proposed project: • Water Quality Certification/Modification • Hydraulic Project Approval • City of Renton Shoreline Substantial Development Permit • City of Renton Grading Permit x -T -3«�'-_-`'-3,=,-�y=-T", - _ -b�= ,~ w r - - -�=•ram_ - __ r 7 - �� - *�'_ `i',�.��':' ..e 1�- _ - __��__ _ = _ _ •� x'- -T am � •fi t -_-- -`—_� �' � _ _ - `y' _ �' :-#- '-=ai .- - _-«--�' $ .. mil• �� - �� _ _--_��'"- �-- ,-� _�.-- ~ �y- --_ • - - ' 41. �"r y � y _`{• ��'� y°=1 _ ., Z �- J.''_�'y ~-� - �'S' _- _. S. i L xrrP �. ` jr IL I Air -tom - . ' -,,y •_, _ _ _y=, _ - _ _ - S '' a . ' - • - = 7 - - - - -. -- ' �• x ZI �1—tJ� �i��F 2�L fin• ' w �,y �� ' - .- _ -.. � L . _ ..� L �r � 1 �. � 1. PURPOSE AND NEED FOR THE ACTION 1.1 INTRODUCTION The project purpose is to provide flood and sediment control for the City of Renton, Washington along the lower 1.25 miles (2000 m) of the Cedar River. The Cedar River drainage basin is located southeast of Seattle, Washington and lies entirely within the boundaries of King County (see Figure 1). The basin is approximately 40 miles (64 km) long, has a maximum width of 10 miles (16 km), and drains 188 square miles (480 kM2) into Lake Washington at Renton (see Figure 2). The City of Seattle operates a water supply system on the Cedar River utilizing Chester Morse Lake and the Masonry Pool (rivermile 37 [59.2 km]) and a diversion at Landsburg (rivermile 21 [33.6 km]). There is a Seattle City Light hydropower facility at Cedar Falls (rivermile 34 [54.4 km]). In 1987, a new spillway was added to Chester Morse Dam as part of the National Dam Safety program. In addition, a roller compacted concrete dam replaced the crib dam that separated the Masonry Pool from Chester Morse Lake. Approximately 80% of the Cedar River basin above Landsburg is owned by the City of Seattle (Seattle) and is closed to development, recreation and general public access, in order to maintain high quality drinking water. Seattle diverts an average of 191 cubic feet per second (cfs) from the river for municipal water supply (King County, 1993). Downstream of Landsburg, the river flows through rural residential lands. In this reach, the river was formerly a braided channel with numerous gravel bars and floodplain gravel deposits. The river is now confined to a relatively narrow channel, with numerous bank revetments or levees, which exacerbate scouring of gravel bars (and downstream transport of sediments) and have cut off the floodplain except during high flows. There are a few bluffs still subject to erosion, and minor channel changes have ocurred during high water. The floodplain is narrow (200-500 feet [60-150 m] wide above Maple Valley and approximately 1000-1500 feet [300-450 m] wide from Maple Valley to Renton) and the valley sidewalls slope up steeply to the surrounding plateau. The lower 3 miles (4.8 km) of river run through the middle of the City of Renton (population 43,473 in 1993, see Figure 3). The Cedar River supports runs of anadromous sockeye, chinook and coho salmon and steelhead trout and adfluvial (lake -dwelling fish that spawn in streams) runs of rainbow trout, cutthroat trout and longfin smelt (see Figure 4). 1.2 STUDY AUTHORITY Section 205 of the 1948 Flood Control Act (as amended by subsequent Water Resources Development Acts) provides for the U.S. Army Corps of Engineers (Corps) to enter into a local/federal cost -shared agreement to plan and construct small flood control projects. Projects include items such as levees, flood walls, channel enlargements, road realignment, bank stabilization and other measures. Each project 1 must be a complete solution to the flooding problem and must not commit the federal government to additional improvements to insure effective operation. The federal share of these projects must not exceed $5 million, without specific Congressional approval. 1.3 FLOODING HISTORY Rivers on the west slope of the Cascade Mountains, such as the Cedar River, are subject to high flows from October through April generated by maritime rainstorms and/or snowmelt. Prior to 1912, the Cedar River did not flow into Lake Washington, but rather flowed into the Black River which joined with the Green River to form the Duwamish which empties into Elliott Bay (see Figure 5). At that time the Black River was the southern outlet for Lake Washington. Periodically, the Cedar would flood and the high water would flow directly into Lake Washington through a large area of wetlands (current location of Renton). At approximately the same time the Cedar River was diverted into Lake Washington, the Lake Washington Ship Canal and Hiram Chittenden Locks were built by the U.S. Army Corps of Engineers. This project lowered the level of Lake Washington by approximately 9 feet (2.7 m), and the flow of Cedar River water was needed to continue water circulation through the lake and ship canal. In 1911, the Corps granted a permit to Commercial Waterway Number 2 to dredge a 6000 foot (1800 m) long channel (depth of 8 feet [2.4 m] below low water, in 1911) to connect the Cedar with Lake Washington at its present location, cutting off flows to the Black River (the lowering of Lake Washington from construction of the Lake Washington Ship Canal and Locks by the Corps cut off all flows from Lake Washington into the Black River as well; see Figure 5). The City of Renton (City) took over maintenance of the Cedar channel in 1957. The City periodically dredged the originally permitted channel, in the lower 1.0 mile (1600 m) of the river, to depths of 10 to 12 feet below current low water. The Corps has not dredged the river channel but infrequently removed large woody debris from the river delta in Lake Washington to assist with navigation until the early 1980s. The City received permits from the Corps to dredge the delta and portions of the channel for flood control at least 4 times from 1960-1982. The City was typically permitted to remove 75,000-125,000 cubic yards (CY) of material, but frequently did not dredge the full amount permitted. The channel has most likely not been dredged to the original depth since 1962 when the north Boeing bridge was placed across the mouth of the river. The channel has not been dredged at all since 1983. In November 1990, a series of storm events occured in western Washington. The Cedar River basin, which was already saturated from earlier storms, could not contain the precipitation and widespread flooding occurred. The Cedar River reached the highest level recorded at Renton since 1945 (10,200 cfs), and the third highest recorded at Landsburg since 1895. Basements of City Hall and adjacent downtown buildings were flooded and the city's municipal airport was closed to air traffic because of flooded runways. Depths of flooding at the airport and Boeing were 3-4 feet (--1 m). Flooding was exacerbated by the amount of sediment accumulation on the river bed in the lower reach. The river channel has been filling in at a rate of 0.1-1.0 feet (0.03-0.30 2 m) per year, on average, and the current channel floods on the left bank (facing downstream) at approximately a 1.6 year flood return level, while the right bank (facing downstream) floods at approximately a 23 year flood return level'. In June 1993, the City obtained a Corps permit to dredge up to 111,000 CY of sediment and debris from the Cedar River delta, with disposal of the material at the Elliott Bay Puget Sound Dredged Disposal Analysis (PSDDA) Site. The basic purpose of this dredging was to eliminate a roosting area for birds (primarily gulls) which was posing a hazard to air traffic at the Renton Airport. Flood control was not increased due to the delta dredging. Dredging was accomplished in the summer of 1993 and lowered the bed to 14 feet (4.2 m) MSL (6 feet [1.8 m] below lake level at low pool). In the spring of 1995, moderate flows (-3000 cfs) occurred in the Cedar River resulting in the transport and deposit of large amounts of sediment into the channel and delta, filling the delta in to approximately 2 feet (0.6 m) below low lake level. In November 1995, a heavy rain storm caused flows to reach 8,600 cfs in Renton causing the airport to be extensively flooded and bringing down a great amount of logs and other debris that was removed by emergency personnel at the south Boeing bridge. The park on the right bank was also flooded. An unexpected heavy rain storm later occurred in February 1996 with an almost equal peak of 8,500 cfs. These two floods caused some scour of sediment in the river channel from Logan Avenue to the mouth and deposited large quantities of sediment (gravels, sands) and debris on the delta, rather than in the river channel. Portions of the delta are now above the winter lake level (20 feet MSL [6 m]). Currently the average depth of the delta bed is approximately 19 feet MSL [5.7 m] (one foot [0.3 m] below low lake -level). The City, by letter dated 4 February 1993, requested Federal assistance in reducing flood damages along the Cedar River within the City of Renton. The Boeing Company, which has a manufacturing facility at the mouth of the Cedar River producing 737 and 757 jet aircraft, supported this request by letter dated 26 February 1993. The Corps conducted an Initial Appraisal under Section 205 of the 1948 Flood Control Act, and determined that the benefits likely exceeded the costs for a structural solution to the flooding problem. The Corps and the City entered into a Federal Cost Sharing Agreement and are conducting a feasibility study. 1.4 NEED FOR FLOOD AND SEDIMENT CONTROL Flood and sediment control is necessary in the lower mile of the Cedar River, within the City of Renton. Current river channel capacity is so reduced that the left bank overflows at 2500 cfs, approximately a 1.6 year recurring event. The right bank overflows at 8000 cfs, approximately a 23 year recurring event. The sediment load coming down the river from eroding banks, and other sources, is very high; the Corps calculated that in less than 20 years, the Cedar River will no longer be contained within ' Flood return frequencies are based on the likelihood of a flood occurring in any given year. For example, there is a 100% likelihood that a 1 year flood level would occur in any given year, there is a 1 % chance that a 100 year flood level would occur in any given year. 3 its channel during low flows and will likely avulse onto the airport and parts of downtown Renton. The sediment load also poses a serious threat to fishery resources. If the channel is filled with sediment to the point that the river flows onto the airport or Boeing property there would likely be large-scale fish stranding and the river would likely be mostly inaccessible to anadromous fish for spawning or other life history stages. Contaminants would likely be carried by the river waters into Lake Washington from the airport and the Boeing facility. 1.5 PROJECT PURPOSE The project purpose is to provide flood control for the City of Renton, Washington along the lower Cedar River. Under the Section 205 authority, the Corps of Engineers is required to select an alternative to provide flood protection that will balance the National Economic Development (NED) alternative and be the least environmentally damaging. A flood control alternative is being pursued because "no action" would cause the flooding situation to worsen and the environmental impacts of no action could also be significant. 1.6 AGENCY AND PUBLIC ISSUES The Federal and State resource agencies and the Muckleshoot Indian Tribe, as well as Trout Unlimited and other members of the public have been involved in this project from the beginning of the planning process. A number of issues have been brought forward by these various entities and are summarized below. A preliminary scoping meeting was held with permitting and resource agencies on 24 May 1995. A public scoping period was held from 1 June 1995 through 30 June 1995 to solicit public comment on the Corps' study as published in the Federal Register, Volume 60, Number 105, 1 June 1995. A public scoping meeting was held on 13 June 1995 in Renton. Resource agency and tribal issues were largely related to the potential adverse impacts to fish and wildlife resources. The Cedar River is an important spawning area for sockeye, chinook and coho salmon and steelhead trout as well as longfin smelt. Bald eagles and numerous migratory waterfowl have been observed in the area. In response to these concerns, the Corps has undertaken several baseline environmental studies with concurrence of the agencies and tribe, which were included as appendices to the draft EIS. Specific concerns included impacts to sockeye spawning, longfin smelt spawning, waterfowl habitat, and possible water quality problems during construction. Public issues included the potential for adverse impacts to fish and wildlife as well as concerns about whether the project will effectively control flooding in the project reach. There are also concerns about the potential for induced flooding upstream. Several scoping commentors noted that the Cedar River Trail Park located alongside the right bank of the project area is an important public facility and should not be removed for a .19 flood control project. Commentors also noted that this project may help restore the declining sockeye salmon population rather than necessarily having an adverse impact. The draft EIS was published in the Federal Register on 4 April 1997 and circulated to the agency and public mailing list developed during scoping (see Section ) for a 45 day public review. A public workshop was held on 29 April 1997 to describe the project and environmental impacts to interested parties. Comments were accepted at the public workshop and written comments were accepted until 27 May 1997. Few comments were received and are included in Appendices A&C of this EIS. The major issues raised by commentors focused on the potential impacts to chinook salmon (in light of their probable listing on the endangered species list), requests for more information on the proposed upstream mitigation site, the possible changes in bird use of the project area and airport following construction of the project, and concerns about the disposal site for the dredged material and future disposal options for maintenance dredging. These comments have been used to design the project to avoid and minimize environmental impacts as well as to design mitigation measures. Unavoidable adverse impacts are described in detail in this EIS and have guided the selection of the preferred alternative which balances economic impacts and flood damages avoided with environmental impacts. 5 of tL- .I y__ '-�- _`._��" '_#',~•ky _ — ��-� tom= o-_ t -�.� ___ ��~ _ _ ,- -.y_,_== I - »f. - _ r - -� ■ -' -I, _lam_ y�r'fill _ _ k _ _ _ . _ - _ •_ �- -yi sY ,ate w�• } �F ? r # �� ! y=--��-�-� Y� �� - _ --_� � .-'fir-' ,..k_=' �.� ''� s � y•'r - , - hog now ar LIVE LF FF _ _ L-• 'J _ —± �—�,- — — _r "- __ J-EY _ _ _ _ _ _ —__ _ _ _ _ _. i �. - Icy - �--� wX ra � *-r$_x " �__ _ -F�*. '~ '�-_ - — -a�•_ - =WX - '•" ' ram' y, _ - - _---_�,''-- .al•C~ - 7� - tY: _�_ -_ mac' T.� - .. = •' - 4 -- �--' -- - - ___- _' • � ��' _ ak nO NAM - tit Wl AK �,. �—y._ _ �.� � _,- � �.__ •-,�',:c�_, =-ems-- - � - -''a_-_ !• � � �'�li- - ' ...... ............ .. ......... ................... .......:::::::::::::....... ......:::... ..::::::::: di .... KA'NG COU N T Y .. ; t atkle Bellevue : . Lake - ammamfsh f w, �~• 'S'�• Lake, Washington, . . . . . . . . . . . . . . . . . . . . W S : H: Rent Vachon island I!•r ra r wt a� " t T>Y . . . . n 4 ;' \+ ,'�w\ ar , 47 CI b Y',y''�'3 +tcY^'^s%�•� .% . t :• 1 ) � tr rf 1 �5 � w : �. Kent,r }r 4M y r K I T T I T A S COUNTY Auburn I� r+l .d �•s •... l . P I E R C E C O U N T Y '-'+�_ ... `• .. ,... �� .. . . . . . . . . . . . . . . . . -~�.a•.. . a . . . . . . . . . .+.... .-,i. . . . .a,.,.,.. It is understood that, while the Corps of Engineers and iniormabon US Army Corps of Engineers �pphers have no indication or reason to believe that there a—n—noes in information incorporated in the basemap, THE CORPS AND ITS FIGURE 1 : VICINITY MAP Date: 6/6/97 SUPPLIERS MAKE NO REPRESENTATION OF ANY KIND. INCLUDING BUT NOT LIMITED TO WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. NOR ARE ANY Preparers LDD SUCH WARRANTIES TO BE IMPLIED WITH RESPECT TO THE INFORMATION. DATA, OR SERVICE FURNISHED HEREIN Legend Lakes /\/Cedar Cedar County & tributaries River basin boundaries N A 4 0 4 8 Miles Sources River information obtained from Washington Rivers Information System (WARIS) database, Washington Department of Wildlife (WDW) and 1994 TIGER data, US Census Bureau Cityboundaries, wetlands and additional data provided by King County. Wetland data is available for the lower basin only Desire Lake Spring Lake n)\ � k� d c �alPey----1-- Landsburg Rock Crook ummlt vensdale lake Retreat 2 0 2 4 6 Miles Legend Cedar &tributaries Renton city limits � Lakes Cedar basin Sources River information obtained from Washington Rivers Information System (WARIS) database. Washington Department of Wildlife (WOW) and 1994 TIGER data, US Census Bureau. City boundaries, wetlands and additional data provided by King County. Wetland data is available for the lower basin only. CD N. CD Cedar River Trail Boeing / Bridge Legend M Cedar River park 17 Lakes Major roads /\Y Cedar & tributaries City limits Source Information Lake boundary Information obtained from Washington Rivers Information System (WARTS) database, Washington Department of Wildlife (WDW). City boundaries, streets, park and river information obtained from King County. N Cn tD �O � Renton edar River DI I < Cedar River CD Natural Zone �q//e r Cedar River FIGURE 3: LOWER CEDAR RIVER It is understood that, while the Corps of Engineers and inf ation suppliers have no indication or reason to believe that there inaccuracies In information incorporated in the basemap, THE RPS AND ITS Corps of Engineers SUPPLIERS MAKE NO REPRESENTATION OF ANY IaND, INC UDING BUT NOT LIMITED TO Date: 1/6/97 WARRANTIES OF MERCHANTABILITY OR FIINESS FOR A P 11CULAR USE, NOR ARE Plate: Draft SERV UCH WARRANTIES TO URNISHEBEII PLIED WITH RESPECT TO TH INFORMATION, DATA, OR 0.2 0 0.2 0.4 I Preparer: LDD Legend Anadromous fish blockage points • Impassable cascade hington Impassable dam Passable cascade Anadromous fish present /V Cedar & tributaries �-� City limits anton Lakes Cedar basin M p coo -• 'z' f J w FalrwO [� M, ! Rattlesnake Lake dar Grove' Hobart waist,_ Tayioij f Desire Lake Lake r` 9Ptin9 Lake-' r""' Chester Morse i Ib `a�i I Lake �� n��.: } .� \•„� _ ram' i Selleck _ ✓� River information obtained from FIGURE 4 A N A D R O M O U S FISH Washington Rivers Information System (W and database, ■ Washington Department of Wildlife (WOW) and It i. underamod that, while the Corp. of Engineer. and information ■ 1994 TIGER data, US Census Bureau. USArmy Corps of Engineers 9uppIIW9 bane nv ir�cation or rea.on to behave tlmt them am Inamraoes in inlon ation incorporated in the b-ap, THE CORPS AND ITS Date: 6/6/97 SUPPLIERS MAKE NO REPRESENTATION OF ANY KIND. INCLUDING BUT NOT LIMITED TO City boundaries, wetlands and addtional data provided Preparer: LDD WARRANTIES OF MERCHANTABILITY OR FITNESS RESPE FOR A PE INFORM USE, NOR ARE ANY ACCESS 1 N CEDAR RIVER V E R BASIN N by ►Gng County. SUCH WARRANTIES TO BE IMPLIED WITH RESPECT TO THE INFORMATION, DATA. OR SERVICE FURNISHED HEREIN. Ty ------- ------- 7 nix'_ 7 _5 eb rg ' h ,l • , ,11.. ryjj' 4y r VP 1-1 Ell 21J:11.1L L4 t•t��l l' L` �- . CGf /-'{ •� t.11L1� - n M. 9 IJ LX_ , 4�1 fi im Tf Zf 4"1 09 IN �Z vxn A� 11, J, Mid: ttppp 04 11 � =.�n' , w'' IF � MR m �,;J -------- -- 7.. 7 rT tv ............ a ---------- FIGURE 5: HISTORIC ROUTE OF THE CEDAR RIVER/BLACK RIVER 2 2. ALTERNATIVES The range of potential alternatives for flood control have evolved from those considered in the reconnaissance phase. Numerous alternatives were intially evaluated based on the following criteria: • If the alternative accomplished the project purpose of providing 100 year flood control in the lower 1.25 miles of the Cedar River. • If the project benefits exceeded the project costs (including environmental costs). Alternatives which did not meet both of the above criteria were eliminated from detailed economic and environmental analysis and are briefly described in Section 2.1. Projects which met both of the above criteria were evaluated in detail and are the basis for the discussion of environmental impacts in this EIS. All alternatives evaluated in this EIS were developed with the use of a hydraulic (HEC-RAS) and sediment model (HEC-6), as described in the draft DPR. 2.1 PLANS ELIMINATED FROM DETAILED STUDY 2.1.1 Upstream Sediment Control. This alternative was identified during the reconnaissance phase as a possible solution to the increased flooding at Renton. Preliminary study during feasibility has identified a large number of sources of sediment. It would be extremely difficult and costly to armor all of the eroding banks along the river valley that are contributing to the overall sediment load. A landslide occurred at RM 3.9 [6.2 km] (behind revetment) in 1987 that contributed approximately 30,000 cy of sediment to the river. This material has likely moved into the project reach and into Lake Washington. Simply controlling upstream sediment sources, even if accomplished, would not sufficiently reduce the existing flooding condition in Renton. The adverse environmental impacts of armoring the river banks and valley walls could be significant and would degrade or remove riparian habitat that is critical to the ecological health of the river system. Levees currently existing in upstream areas have likely decreased the value of spawning areas by increasing channelization and scour of the river bottom. Land use policies to reduce erosion in the upper basin from building, farming and forestry practices are an important part of the Cedar River Basin Plan, an interagency land use document completed in 1996. Renton is working closely with King County to implement sediment control measures to reduce sediment input into the lower reach of the river. While certainly a worthwhile goal in its own right, this alternative would not accomplish the basic project purpose of providing 100 year flood control in Renton. 2.1.2 Upstream Levee Removal. This alternative was also identified during the reconnaissance phase. Levees or other bank protection devices are present along 64% of the river on at least one side (King County, 1993). Preliminary study during feasibility -has shown that the removal or setback of levees upstream of Renton only reduces flood levels in the immediate vicinity and does not measureably reduce 11 flooding in Renton. When the Cedar River has a major flood, most levees upstream are overtopped and the valley acreage behind those levees already stores flood waters. Further, the Cedar River floodplain, upstream of Renton, is narrow and bordered by steep valley walls. There is not enough storage in the floodplain to reduce flood stages in Renton. It is true that the removal of levees would have tremendous fish and wildlife benefits; however, the primary purpose of this project is flood control. King County is attempting to buy out the most flood prone homes in the upper valley with the long term goal of removing some levees. The County's general policy is to not allow new levees along the Cedar. This alternative would not accomplish the basic project purpose of providing 100 year flood control in Renton. 2.1.3 Widening the River Channel in the Project Reach. This alternative was identified during the reconnaissance phase as a possible solution to the increased flooding at Renton. The lower 1.25 miles [2 km] (project area) of the Cedar River are tightly confined between the Renton Municipal Airport and the Boeing manufacturing plant, and other urban development upstream of Logan Avenue. The river channel could only be widened on the right bank to 150 feet [45 m] (current channel is 110 feet [33 m] wide in entire reach) from Logan Avenue down to the south Boeing bridge and to 250 feet (76 m) wide from the south Boeing bridge to the mouth. The two Boeing bridges would not be widened and would remain at 110 foot (33 m) spans. This alternative would reduce flood water levels by approximately 2 feet (0.6 m) from the mouth up to the south Boeing bridge and by a negligible amount above that location. Sediments would continue to accumulate in the project area reducing flood capacity over time. This alternative would not accomplish the basic project purpose of providing 100 year flood control in Renton and would require the complete elimination of the Cedar River Trail Park, a heavily used recreation feature. 2.1.4 Modifying the Boeing Bridges to be Raised During Flood Events. This alternative was identified during the reconnaissance phase as a possible solution to the increased flooding at Renton. After modelling flood flows, Corps' staff found that the north Boeing bridge (mouth of river) does not worsen flooding, provided it is kept reasonably free of debris, because it is at lake level. The south Boeing bridge is approximately 5 feet (1.5 m) above the river bottom and during flood events the bridge, traps much of the debris coming downriver and frequently overtops with flood waters. The pressure from trapped debris can cause damage to the bridge and could cause the bridge to fail entirely during a very high flow. Modifying the south Boeing bridge to be raised during high flows would eliminate the problem of debris being trapped and avoid bridge damage during flooding. It would also reduce flood elevations in the immediate vicinity of the bridge, but would not significantly reduce flooding upstream of the bridge. This alternative, alone, would not accomplish the basic project purpose of providing 100 year flood control in Renton, but is further evaluated in combination with other project elements in section 2.2. 2.1.5 Nonstructural Floodproofing of Buildings in the Project Area. This alternative was identified during the reconnaissance phase as a possible solution to the increased flooding at Renton,. Economic damages experienced during the 1990 flood 12 event occurred primarily to equipment, supplies and inventory located at floor level or other low spots on the Boeing property or at the airport. Floodproofing measures could include raising the equipment inside the buildings off the ground, securing equipment above flooding levels, moving planes at risk to higher spots on the runway or flying completed planes to another airport when flood warnings are issued. These measures alone would not protect the south Boeing bridge, which would still experience closures and/or damages during flood events nor would it prevent the river from eventually breaking out of the channel. This alternative would reduce the damages which occur during flood events, however; this alternative, alone, would not accomplish the project purpose of providing flood control in Renton. However, these measures may be implemented regardless of the flood control alternative chosen to reduce damages during floods in excess of the project's "design flood." Planes will be moved to higher ground or flown to different airports under the operating manual produced with any of the action alternatives described in section 2.2. 2.1.6 Dredging the Lower Mile To Historical Depths. This alternative was identified during the reconnaissance phase as an alternative that has federal interest (economic benefits exceed economic costs). Historically, the lower reach of the River was dredged 8 feet (2.4 m) below the winter water level of Lake Washington. This amount of dredging would extend lake habitat, during low and moderate flows, more than 1 mile (1600 m) upstream from the mouth of the Cedar River. Resource agency comment on this alternative, during the reconnaissance phase, was severe regarding the potential impacts on sockeye salmon spawning and sockeye fry migration into the Lake. Because this alternative would essentially move the lake backwater upstream, sediments would be deposited more rapidly in the project reach, because of lower velocities in the area, than with the existing condition. Sediment model calculations indicate that the project area would have to be redredged every year to contain the design flood. This alternative alone would provide approximately 25 year flood control but would not accomplish the project purpose of providing 100 year flood control in Renton. However, this alternative is evaluated in combination with other elements in section 2.2. 2.1.7 Levee Placement Along the Lower Mile. This alternative would place levees on the right bank from Logan Avenue down to the mouth and on the left bank from Logan Avenue down to the airplane hangars located at approximately 1800 feet (540 m) upstream of the mouth with a low berm below that point to the mouth on the left bank (described in section 2.2 as part of all action alternatives). This alternative would still allow residual flooding of the airport downstream of the hangars. Flooding would be restricted to runway areas. This alternative would not address the continued sediment buildup in the chan-nel and eventually the channel would fill in enough to severely reduce the level of flood protection, ultimately creating a perched channel that would render the south Boeing bridge unusable during the rainy season and potentially cause a bridge failure. This alternative would accomplish the project purpose of providing flood control in Renton temporarily. However, it does not provide a long-term solution to the flooding problem and would require further federal or local government 13 commitment. This alternative is evaluated in combination with other elements in section 2.2. 2.1.8 Sediment Trap. This alternative would require the dredging of a sediment trap, likely to be located in the vicinity of Logan Avenue. This trap would be dredged periodically to prevent any further accumulation of sediment in the project reach. This alternative would not address the existing flooding problem in the lower mile and is similar to the no action alternative (Section 2.2) except for preventing further accumulation of sediment. There would not be any increase in flooding above the existing condition. This alternative, alone, would not accomplish the project purpose of providing flood control in Renton. Initially, this alternative was evaluated in combination with dredging and levee elements, but was determined to not significantly delay redredging of the entire project reach. The sediment model indicates that the trap slows flow sufficiently that deposition levels increase, causing the trap to fill in during the course of one winter. This alternative is not evaluated further. 2.2 ALTERNATIVES EVALUATED IN THIS EIS. 2.2.1 No Action. This alternative, as required to be analyzed by NEPA and Council on Environmental Quality (CEQ) guidelines, would take no action to control flooding in Renton. The sediment load from upstream sources would continue to accumulate in the project reach until all (or most) flood carrying capacity is eliminated. In less than 20 years in the future, the channel would be filled in with sediment and the River would avulse into the urban area of Renton. Economic damages would continue to accrue, with expected annual damages with future conditions (used 10 years in the future) of $11-14 million. Because current land uses adjacent to the river will continue to be industrial, it is likely that infrequent emergency dredging by the City may occur to prevent the river from completely avulsing onto the airport. The no action alternative would not accomplish the project purpose of providing flood control in Renton and would likely have severe environmental impacts, such as preventing upstream fish access from the lake. 2.2.2 Existing Channel Depth With Levees and Modifications to the South Boeing Bridge (see Figure 6) This alternative would require limited dredging (31,000 CY) to even out the channel bottom to the existing thalweg depth. Levees or floodwalls would be required along the right bank from 1-405 to the mouth and on the left bank from 1-405 to just downstream of the airport hangars, plus a low berm from the airport hangars down to the mouth. Levee/floodwall height would average about 7-8 feet (2.1-2.4 m) in height, depending on existing bank height. This particular alternative would require modifications to the bridges at Logan, Williams and Wells Avenues and Bronson and Hauser Way in order to avoid inducing flooding upstream. As with all levees or floodwalls discussed in this and other dredging alternatives, the left bank below Logan Avenue for 400 feet (120 m) downstream would require bank protection in addition to a levee or floodwall because this bank is actively eroding. Riprap would be placed below the ordinary high water mark (OHWM) to protect the bank. Modifications would be made to the south Boeing bridge to raise the span during flooding events in 14 order to prevent debris clogging and induced flooding upstream. New concrete abutments would be placed under the bridge to support the hydraulic jacking system. The channel would require maintenance dredging of approximately 114,000 CY every three years' to maintain existing channel bottom. The total construction cost of this project is estimated to be $10.9 million. 2.2.3 Minimum Dredging Combined With Levees and Modifications to South Boeing Bridge (see Figures 6,7,8 &9). This alternative would require dredging to an average depth of four feet below the existing grade from the Cedar mouth up to Logan Avenue and then sloping up for 800 feet (240 m) upstream to meet the existing gradient, with zero dredge at the end point at Williams Avenue. Initial dredged quantity would be approximately 158,000 CY. This alternative would not require dredging of the delta for flood reduction; however, the channel directly outside (maximum of 20 feet [6 m]) the north Boeing bridge would be dredged to avoid trapping debris on the bridge. Levees or floodwalls would be placed along the right bank from Williams Avenue to the mouth and on the left bank from Williams Avenue to just downstream of the airport hangars, plus a low berm from the airport hangars down to the mouth. Levee/floodwall height would average about 6 feet (1.8 m) in height, depending on existing bank height. Modifications would be made to the south Boeing bridge to raise the span during flooding events in order to prevent debris clogging and induced flooding upstream. New concrete abutments would be placed under the bridge to support the hydraulic jacking system. The dredged channel would need maintenance dredging of approximately 171,000 CY every three years to maintain initially constructed bottom depth, on average. This alternative would accomplish the project purpose of providing flood control in Renton and the benefits exceed the costs. The total cost of this project is estimated to be $8.3 million. 2.2.4 Moderate Dredging Combined With Levees and Modifications to the South Boeing Bridge (see Figure 6). This alternative would require dredging to an average depth of 6 feet below the existing grade from the Cedar mouth up to Logan Avenue and then sloping up for 1200 feet (360 m) to meet the existing gradient with zero dredge at the endpoint just upstream of Wells Avenue. Initial dredged quantity would be approximately 195,000 CY. This alternative would not require dredging the delta; however, the channel directly outside (maximum of 20 feet [6 m]) the north Boeing bridge would be dredged to avoid trapping debris on the bridge. Levees or floodwalls would be placed along the right and left banks as described in alternative 2.2.3 but would average about 5.5 feet (1.7 m) in height depending on existing bank height. Modifications would be made to the south Boeing bridge to raise the span during flooding events in order to prevent debris clogging and induced flooding upstream. New concrete abutments would be placed under the bridge to support the hydraulic jacking system. The dredged channel would need maintenance dredging of approximately 176,000 CY every three years, on average. This alternative would Z The sediment model conservatively estimates the maintenance dredge frequency for all action alternatives at every three years. Historical sedimentation rates (1986-1994) indicate maintenance dredge frequency would be on the order of every 10 years. 15 accomplish the project purpose of providing flood control in Renton and the benefits exceed the costs. The total cost of this project is estimated to be $8.5 million. 2.2.5 Deep Dredging Combined With Levees and Modifications to the South Boeing Bridge (see Figure 6). This alternative would require dredging to a depth of 10 feet below the existing grade from the Cedar mouth up to just below Logan Avenue and then sloping up for 1200 feet (360 m) above Logan Avenue to meet the existing gradient, with zero dredge at the end point just upstream of Wells Avenue. Initial dredged quantities would be 260,000 CY. This alternative would not require dredging of the delta; however, the channel directly outside (maximum of 20 feet [6 m]) the north Boeing bridge would be dredged to avoid trapping debris on the bridge. Levees would be placed along the right and left banks as described in alternative 2.2.3 but would average about 4.5 feet (1.4 m) in height depending on the existing bank height. Modifications would be made to the south Boeing bridge to raise the span during flooding events in order to prevent debris clogging and induced flooding upstream. New concrete abutments would be placed under the bridge to support the hydraulic jacking system. The dredged channel would need maintenance dredging of approximately 185,000 CY every three years, on average. This alternative would accomplish the project purpose of providing flood control in Renton and the benefits exceed the costs. The total cost of this project is estimated to be $9.3 million. 2.2.6 Possible Dredging Methods for All Action Alternatives For all action alternatives, dredging will be required. The dredging would remove riverbed sediments at the various depths described above. In the lower portion of the river, the lake backwater provides depths sufficient to float a barge and would allow the use of barge mounted equipment as described below. In the upstream portion of the river, water depths during the summer construction season would be 1 foot (0.3 m) or less in most locations and would require another method of dredging. 2.2.6.1 Barge Mounted Clamshell Dredge or Dragline A barge mounted clamshell dredge would likely be used for the minimal, moderate and deep dredge alternatives in the lower portion of the project area (from the mouth upstream approximately 3000 feet [909 m]; 5200 feet [1575 m] for deep dredge; see Figure 10). The clamshell would remove sediments, but returning water and fine materials would be significant from the clamshell head. Alternatively, a barge mounted dragline could also be used in the lower portion of the project area. This method would drag an excavator bucket across the channel scooping up material that would be deposited onto the bank on the park side. Material from either method would be placed in a dewatering area on the park side of the river, with appropriate measures taken to control return of turbid water. This area would be lake backwater and silt curtains or booms could be utilized with either method to minimize the turbidity plume that would arise during dredging. W-1 25 20 J V7 1 5 Existing Channel Z Four Foot Dredge O — — — Six Foot Dredge 10 Ten Foot Dredge W J 5 0 ap p cdvp� �p p �ppp 1� avdp 8 (ObV� O (D Lc)M M ch �D 00cD f�0 tD h ap CHANNEL DISTANCE (ft) W > FIGURE 6 DREDGE PROFILES FOR ACTION ALTERNATIVES w LEGEND __�__= LEVEE FLOODWALL FIGURE 7 LEVEE/FLOODWALL FOOTPRINT FOR PREFERRED AVrERNATIVE (S SHEETS) DATE AND TIME PLOTTED: 13-MAR-1997 14:07 100' 50' 0 100, 200' r = 100' I H H p H Hi U. S. ARMY ENGINEER DISTRICT, SEATTLE CORPS OF ENGINEERS SEATTLE, WASHINGTON SHEET 1 CEDAR RIVER SIZI INVITATION NO. FILE NO. B DSGN BRANDT CHK: DESIGN FILE: I:0designs0crfc0civ0cr-dprl.dgn WASHINGTON PLATE CI.I SHEET ' I SCALE: 1 100' I Q 1 .............. x.. _........ �. IT w ( SMALL- PLA F— M NE HANGARS cn I t i ' t 01 �...... ....... ........ ...._. ....... ...... ... .... ....... .._........... .....,, <:................ : .. ..._ ... ...u�+q=xv,n1•.... M�'ii; ...-tilf"`:C. lIN ..iW C E D A R R I V E R FL FIGURE 7 (CONT.) SMALL- PLAN E HANGARS ...... _......... 41• ..__............... __... FLOODW ALL TYPE 11 ......1 ....................... .... ......... ..... ........................................ OTTED: 13-MAR-199' 14:10 a ............ .«..._... .................................... ...................................._......................._.........................................................................._......_....................... W _.............. «............ ... _...... ..... ......................................._............._................._......»................_........................................_..........._.............................. F- N o�:= _: '=.-__�.-_-� �".... -mo «__.........._.................. ........ _:.........._...............__...........»..................._.. _.. - _ ..................._..._......................................_......�..... _ ._ . .... .....,t........ • �..............«. LEVEE TYPE: III L 25+00 Iu H Cl ASl1DF STDlJCTl1DF ....... ..... ...... ...... ..... ...... ...... ...... ...... ...... ...... ..... ..... ...... ...... ..........................................._......_.........._ ��„". - ...............................................................vN,............................................_.....»......_.........»......................_........................... 100' 50' 0 100, 200' r = 100' I H H pr U. S. ARMY ENGINEER DISTRICT, SEATTLE CORPS OF ENGINEERS SEATTLE, WASHINGTON SHEET 2 CEDAR RIVER WASHINGTON SIZE INVITATION NO. I FILE NO. PLATE B DSGrI: BRANDT C"-. IGN FILE: I:OdesionsOcrfcOcivOcr-dor2.dgn C 1.2 SHEET SCALE: 1 = 100' Q .. _ x _ _ ... . :J LLI aw ... ............... F ............;....:.._;..._ N O .......... ,__ ..................... :.......... = ... ......,:........:- ..rn, :m ...................... ..._....L.... ,..............................._......__......... .. .. �I FLOODWALL TYPE L 50+00 _ C E D A R R I V E R I FLOW ,•........... _. _LEVEE TYPE 11 � r R50+00` 1 ,I, z .............. ....... _--4. F _... ,...... . M�.�•.�- ..(Py,y,.:..: ... : TRAIL ... i.:.. 1049% r: FIGURE 7 (CONT.) ... :; ._.. ... ............ •; a ... . D. ............._. i a + .j r I z .. _ ?; ? CLOSURE STRUCTURE ^� .W F : F i _.. :F «_.. _........... IF W a q.: r...... __._.•_.. , i _..................... _l : -_._. f .. , i v,_.......- • . i .......... :1 G t'j —: i "RUA '• ....... ........ ........ ....... ...... O ... _.., ................... L 45+00t w.._. LEVEE~ TYPE 1 L 40+00 IQ SOUTH -` BOEJNG BRIDGE FLOODWALL TYPE I R 40+00 R45+00 YP EI 1 LE :E.. . .v. a .._._. ..................'•"-�+svl..: ,:: - .. a ...,:...:....;....... � ....:....::: :va .. x•. •...... • ..... •it„u„ .t 3YL •. r. rn 1. ..v.:.,: a .. b ........ • .. , . •a,. ,..... , _ f � .. .. • • .• 11•IIIIL ♦ . �..._. _. y,_.. Syr. '�. n9!!V:i'�4-_,�::�, n� ...e.•— +--.. ........ .�J1^•. r` may.. �Y.:, _i :. .., '�rR Tom: , �� I••IIIIIt—RI:w�� rn�I:•••..'••".,,• _. 'TRAIL'• 7; :..... . _ ...+"....ram...•}_ — .. _�t.... l .._ ... ? > .:•,:.. , -_ ..x. A 1 ....................._ i,_ ....... ....... 1 - _.... -1 ............k .... , I .... i :. C5 ' F.. w.r...::: .....................: • • y t_......... f ? ?PfURE "�,+...._..:.... t CLOSURE ` S T R U,' i ..'�._ � � t z :e �. `'•. ...,...�:.. :::1 �1 : fr .i 100' 50' 0 100, 200' " = 100' CH H:E�fi-_ U. S. ARMY ENGINEER DISTRICT, SEATTLE CORPS OF ENGINEERS SEATTLE, WASHINGTON SHEET 3 CEDAR RIVER WASHINGTON SI:'E I INVITATION N0. FILE NO. PLATE El ICI.31 DSGN: BRANDT CHK: SHEET DATE AND TIME PLOTTED: 13-MAR-1997 14:12 DESIGN FILE: 1:0desians0crfc0civ0cr_dpr3.dgn SCALE: 1 100' �. I00' 50, 0 100, 200' I = I00' U. S. ARMY ENGINEER DISTRICT, SEATTLE CORPS OF ENGINEERS SEATTLE, WASHINGTON FIGURE 7 (CONT.) SHEET 4 CEDAR RIVER SIZE I INVITATION NO. FILE WO. B DSGN, BRANDY CHK: IME PLOTTED: 13-MAR-1997 14:14 DESIGN FILE: 1:0designsocrfcocivocr_dpr4•dgn Z Q J Lill H N O F- 2 U F-- Q WASHINGTON PLAIT C1.4 SHEET SCALE: 1 = 100' FIGURr. f 0own 1.1 100' 50' 0 1.00, 200' U. S. ARMY ENGINEER DISTRICT, SEATTLE CORPS OF ENGINEERS SEATTLE, WASHINGTON SHEET 5 CEDAR RIVER SIZE INVITATION NO. FILE NO. - B I DSG14: BRANDT Tc-lll- WASHINGTON PLATE C1.5 E AND TIME PLOTTED: 13-MAR- 199 f 14: 16 DESIGN FILE: I;Odesi SHEET SCALE: 1 = 100' E ALIGNMENT 1.5' 1 1.5' . 2" MIN. TOPSOIL AND SEEDING EM� EXISTING GROUND I LEVEE BaNKMENT MATERIAL I� SURFACE 2 I 2 ur o STRIP 6" AND REMOVE UNSATISFACTORY MATERIAL LEVEE TYPE I NOT TO SCALE [ ALIGNMENT 1.5' 41 4' 1.5' 2' MIN. TOPSOIL AND SEEDING 1 3" AC PAVEMENT 3 LEVEE EMBANKMENT 4" GRAVEL BASE MATERIAL I ------------ _ _ 3 STRIP 6' AND REMOVE UNSATISFACTORY MATERIAL LEVEE TYPE II NOT TO SCALE C ALIGNMENT I LEVEE TYPE III NOT TO SCALE IS' MIN. ROCK SLOPE PROTECTION 4" MIN. TOPSOIL AIRPORT SIDE AND SEEDING STRIP 6- AND REMOVE UNSATISFACTORY MATERIAL I 1 I 1 \ ' �-EXISTING TREES > / 1 I 1 / / / t A\IGNMENT 1 I STEEL CHANNEL � � I 1 / I 1 I 1 I I I I I 1 I 1 1 EXISTING AC ROAD r Ji EXISTING _ GROUND LINE STEEL SHEETPILE Li FLOODWALL TYPE I NOT TO SCALE E ALIGNMENT STEEL CHANNEL STEEL SHEETPILE TOPSOIL AND SEEDING OVER RIPRAP 14 zli �I 7 EXISTING GROUND LINE IPRAP SPLASH APRON FLOODWALL TYPE II NOT TO SCALE FIGURE 9 TYPICAL FLOODWALL SECTIONS NOW- .Ccf May ..I - •;ram.. � ,. � � � -�. ,R _ IV Y - � _ ,� . • � r.��F.7 ,yam:,;-.;s• •r ` �' � : si:�� FIGURE 12: Hydraulic pipeline cutterhead dredge. 2.2.6.2 Hydraulic Suction Dredging of Fine Materials In the lower 2000 feet (606 m) of the river, the sediment is likely small enough (silts, sands and small/medium gravel) to be able to use a hydraulic suction dredge to pump the material onto the park or onto a barge anchored outside of the delta (see Figure 2). This method would likely be very rapid (several thousand cubic yards per day aredged) and would be suitable for transporting fine materials to the Elliott Bay PSDDA site, or for resale. 2.2.6.3 Divert River Flow for Removal of Dry Material This method would place fill material (likely gravel from gravel bars) in the center of the channel with a coffer dam (probably an inflatable water bag) at both the upstream and downstream portions of the dredging area to allow material to be dredged in the dry without fine materials washing into the river (see Figure 11). Actual dredging could be accomplished by an excavator. The river flow would be diverted around the dredging area by the coffer dams. All heavy equipment would be driven on top of the gravel berm in the center of the river, to avoid pollutants washing off the machinery in the river. Material should not need dewatering, but may be stockpiled temporarily before rehandling to trucks for transport to upland disposal site. 2.2.7 Disposal Site for Dredged Material All dredging options will likely utilize the Narco site immediately upstream of 1-405 on the left bank of the river to place dredged material (see Figure 13). This site was formerly an industrial facility and the existing site has concrete/asphalt over much of the site with grass and other natural vegetation along the river bank. This location requires a truck haul of approximately 1.6 miles (2.6 km) from the Cedar River Trail Park entrance. This site will be available for approximately 20 years following initial construction and can be used to temporarily store material from maintenance dredging. 26 The City of Renton may pursue the sale of the material to private entities, such as the Port of Seattle or other developers in the Lake Washington basin. Final disposition of the material will be in accordance with appropriate planning and regulatory procedures. It is possible that Renton may wish to send some of the clean, fine material to the PSDDA site in Elliott Bay because it may not be usable. If sediment is rehandled or pumped onto a barge, the barge(s) will need access to a point close enough to the river or park to enable material to be either conveyed on a conveyor belt or by some other method. The north Boeing bridge effectively restricts access to the river and the delta is generally too shallow for barge access. Because the delta does not need to be dredged for flood control, any dredging of the delta for other purposes would require a permit process outside of this flood control project. A barge could be moored close enough to the Boeing property without dredging, to allow a hydraulic pump, conveyor belt or temporary dock structure to be utilized to rehandle all sediment to the barge(s). All sediment will be tested for contaminants and its suitability for either openwater or upland disposal. 27 B C D FIGURE 13: LOCATION OF NARCO SITE G H J A B 01994 Thomas Bros. 3. AFFECTED ENVIRONMENT 3.1 GEOLOGY/SOILS/SEDIMENTS 3.1.1 Geology. The Cedar River basin extends from the crest of the Cascade Mountains down to Lake Washington. The eastern portion of the basin begins in the southern Washington Cascades physiographic province, as characterized by Franklin and Dyrness (1973). This bedrock of the province is primarily igneous, although some sedimentary rocks are present. The age of the bedrock is primarily Eocene epoch (approximately 40 million years old) or younger. Some of the sedimentary bedrock contains significant coal deposits which were mined in the last century. Glacial activity has been extensive in the region and most of the bedrock is buried under extensive layers of glacial till, glacial outwash and glaciolacustrine deposits. Geologists have hypothesized that an ancestral Cedar River flowed into the Snoqualmie River basin prior to the most recent glaciation because the Snoqualmie drainage is currently blocked from the Cedar by a glacial moraine, not bedrock (USACOE, 1979). The Cedar River flows out of the Cascades and into the Puget Trough physiographic province. The long southeast -northwest river valleys such as the Cedar River and Green River basins were shaped by glacial lobes extending from the north. Glacial ice occupied the Puget Lowland and Cascades many times during the last million years. The most recent ice -sheet to advance occurred about 15,000 years ago; the Vashon glaciation. As the ice receded, glacial outwash was deposited in many areas. These deposits are sands and gravels over glacial till and are exposed in the valley wails along much of the main Cedar River valley. The modern Cedar River valley was scoured during the draining of the glacial Lake Russell as the ice melted, creating a steepwalled and narrow valley. The modern Cedar River has meandered back and forth through its floodplain and obliterated most remnants of the initial incision of the valley. The existing valley and the broad flat floodplain which the City of Renton is built on consist largely of alluvial deposits from the river, and some lacustrine sediments. The lower 1.5 miles (2.4 km) of the river existed only as an overflow channel during flood events in pre -settlement times. As described in the introduction, the Cedar River formerly flowed into the Black River which was the outlet for Lake Washington and then into the Duwamish River which flows into southern Elliott Bay. Prior to development, the floodplain where the City of Renton now exists was a large expanse of wetland that seasonally flooded from Lake Washington. In 1912, the channel to connect the Cedar River to Lake Washington was dredged and the Ship Canal lowered the lake by 9 feet (2.7 m). 3.1.2 Soils/Topography. The soils surrounding the project area are largely fill material placed in the former wetlands of the Black River and shallow Lake 29 Washington waters. The soil is designated urban on the King County Soil Survey (USDA, 1973) and soil boring information on the Boeing property indicates that approximately the first 5-7 feet (1.5-2.1 m) of soil are fill material consisting of sands and silts. Beneath the fill material is at least 100 feet (30 m) of interbedded fluvial and lacustrine sediments (Landau Associates, 1989). The river channel banks have been armored with various items such as gabions, wood -paneled flood walls, sand bags, concrete and riprap along much of the lower mile. Many of these protective structures are eroding or otherwise in disrepair. In the project reach, the topography is generally flat, filled floodplain. The adjacent park has some higher mounds, possibly created by sidecast dredged material. Upstream of the project area, the floodplain terrace soils are riverwash gravels, Pilchuck loamy fine sands, and Puyallup fine sandy loam. The steep banks bordering the floodplain on most of the river are largely Alderwood and Kitsap soils with slopes from 25 to 70 percent. These soils formed from glacial deposits under coniferous forest. 3.1.3 Sediments. The sediments in the river channel have been deposited over many years from upstream sources such as eroding banks. The overall sediment yield of the river has been estimated by King County (1993) to be greater than 65,000 tons of material per year. The finer sediments are likely carried down to the project reach and Lake Washington each season. The coarser gravels and cobbles move more slowly down the river on the order of 1,000 feet (300 m) per year. During flood flows this material is transported much more quickly and may be carried through the project reach to the delta (as was observed in 1995 and 1996). NHC (1992) estimated that 8,000 tons of sediment are deposited annually in the lower 2 miles (3.2 km) of the river. Hydraulic modelling by the Corps indicates that a range of 0.1-1.0 feet (0.03-0.30 m) of sediment accumulates in the project reach per year. The channel sediments from Logan Avenue to the south Boeing bridge are typically medium gravel with some larger pieces greater than (>) 1.5 inches (37.5 mm) in diameter. Low flows deposit fine materials in this reach during summer and fall. Sediment sampling conducted by the Corps in September 1994 (NHC, 1995) shows that at locations between Logan Avenue and the south Boeing bridge, the sediments are >50% small to large gravel with 17-21 % fines (less than 0.03 inches [<0.85mm]). Sediment in the few pools or slower water areas along the banks is typically silt. Below the south Boeing bridge, the center of the channel is mostly small to large gravel, but along the banks there are a few deeper pools under the willows and bank armoring that have mostly sand and silt substrate. From 1000 feet (300 m) above the mouth down to the north Boeing bridge the substrate is mostly small gravel and sands because of the backwater influence of Lake Washington. During the high flood flows in November 1995 and February 1996, large gravels were carried into this lowest reach of the river and out onto the delta. Typical low and medium flows (<2000 cfs) generally bring down finer sediments and cover the gravels at the river mouth with sands and silt. Off, 3.1.4 Floodplain Management. The Cedar River floodplain is narrow over most of the upper reaches below Landsburg dam. Above Maple Valley, the floodplain averages 200-500 feet (60-150 m) in width. Below Maple Valley, the "canyon" widens out and meanders through a floodplain of 1000-1500 feet (300-450 m) width and enters the City of Renton, most of which is constructed in the former floodplain and delta wetlands of the Cedar River and Lake Washington. The upper river has relatively sparse residential development with towns located typically on the low plateaus above the river at Cedar Grove, Maple Valley and Landsburg. Residences are located low in the floodplain in many areas of the river and are prone to serious frequent flooding. King County has been discouraging development in these areas since 1991 with their Flood Hazard Reduction Plan. The City of Renton is subject to infrequent flooding, except in the lowest reach of the river, where the Airport floods at a 1.6 year recurrence flood. The City of Renton is moderately to heavily dense residential, commercial and industrial development. Flood protection is proposed to protect the dense urban development which already exists (and was partially protected by the previous maintenance conducted by the City of Renton) rather than causing undeveloped lands to be protected. 3.2 WATER 3.2.1 Surface Water. The Cedar River drainage basin encompasses approximately 188 square miles. Precipitation in the basin increases with elevation from a low of 42 inches/year (106 cm) in Renton to a high of 104 inches/year (262 cm) at Chester Morse Lake. Maritime storms from the Pacific Ocean can cause heavy precipitation and flooding between the months of October and March. Snowmelt later in the spring infrequently causes flooding if the snowpack is extensive and spring temperatures are high. In 1990, flooding was caused by rainfall on a heavy snowpack in the higher elevations. The City of Seattle operates the Masonry Dam at RM 37 (59 km) which impounds waters from approximately 78 milesZ (200 kM2) of the upper basin (42% of basin). This dam is operated for water supply for the City of Seattle and is only incidentally operated to control flooding in the lower basin. The water supply diversion at Landsburg (RM 21) removes on average 190 cfs throughout the year from the river flow. Seattle claims a right to divert up to a yearly average of 464 cfs, however this use has not been officially determined. The low -flow minimum for the river, set by WA Dept of Ecology is 130 cfs in normal water years and 110 cfs in "critical' water years. During the flood season (October -March), the service spillway gate at Masonry Dam is left fully open. In extreme high water conditions, the emergency spillway gates can be opened to protect dam stability. There has been leakage of reservoir waters into the porous glacial moraine soils near the dam, in the past. In 1918, seepage into the glacially deposited north bank from raising the pool level too high caused a landslide and flood in Boxley Creek to the north of the dam in the Snoqualmie River basin. Since that time, and following several studies, Seattle has limited the pool level in Chester Morse Lake to 1570 feet (476 m) elevation during peak flood conditions that last up to a week and less than 1565 feet (474 m) for longer durations. 31 Other water rights have been granted for domestic use and power generation. The Corps has also claimed a right to use Cedar River water, up to the full natural flow of the river, for Lake Washington regulation. The water level in Lake Washington is regulated by the Corps at the Hiram Chittenden Locks. Lake level varies by 2 feet (0.6 m) between the winter flood season and the summer high locks usage period. From October 1 through February the Lake is kept at 13.2 feet MSL (4 m), and then incrementally raised to 15.2 feet MSL (4.6 m) by May 13. The high lake level is maintained through the end of July and then incrementally lowered to 13.2 feet MSL. During low lake level, the Cedar River flows throughout the lower reach and onto the delta. During high lake level, the lower 1000 feet (300 m) of the river is lake backwater under current conditions. 3.2.2 Groundwater Groundwater resources in the Cedar River basin are largely positioned in glacial materials. Perched groundwater tables in such glacial materials frequently occur above hard packed glacial till and shallow aquifers exist where precipitation has percolated into the glacial sands and gravels. The reservoir impounded by the Masonry Dam percolates an unknown quantity of water into the glacial moraine on the north side of the dam. It is assumed that approximately 80% of this water returns through groundwater aquifers to the Cedar River further downstream (King County, 1993). Approximately 20% percolates into the Snoqualmie River basin. Many of the smaller tributaries to the Cedar downstream of Landsburg arise from seeps and springs out of the steep valley walls. The Cedar River recharges the alluvial floodplain groundwater during high flows and in many locations this water returns to the river via wetlands and groundwater fed channels. Groundwater typically moves downhill paralleling the river channel. The City of Renton has an aquifer located at very shallow depths extracted by a wellfield just upstream of downtown and near the Maplewood Golf Course (King County, 1993). This aquifer is a "sole source" and is highly protected for drinking water purposes. Because of the high permeability of alluvial deposits this aquifer could easily be contaminated by surface pollutants. 3.2.3 Contribution of Tributaries Below Landsburg The tributaries below the Landsburg diversion, at RM 21.6 (34.6 km), contribute approximately 30% (annual average) of the river flow seen at Renton. These tributaries headwaters are located on the plateaus to the north and south of the Cedar River and are all less than 9 miles (14.4 km) in length. There are six major tributaries below ' MSL is calculated using the National Geodetic Vertical Datum (NGVD) 1929. The level of Lake Washington is also frequently referred to as varying between 20 and 22 feet. The datum for this measurement is the Corps datum at the Hiram M. Chittenden Locks. 32 Landsburg and several unnamed smaller tributaries. Most of these tributaries, in the past, supported spawning populations of coho and chinook salmon, and occasionally sockeye. The City of Kent diverts an average of 6.2 cfs from a spring that feeds Rock Creek (tributary that enters Cedar at RM 18.15 [29 km]) and another diversion ditch from Rock Creek headwaters diverts approximately 5.0 cfs into the Green River basin (King County, 1993). Kent may be authorized to divert as much as 22 cfs from Rock Creek and nearby groundwater sources. Water yield (percent of precipitation that discharges as streamflow) from the tributaries basins below Landsburg Dam varies from 48-60% of average annual precipitation. The more developed basins such as Taylor Creek and Orting Hills have higher stream flow yields that can cause higher flood flows during winter and reduced low flows during summer. King County's (1993) current and future conditions report estimates that water yield will increase with continuing future development and this will exacerbate flooding problems. 3.2.4 Water Quality Water quality in the Cedar River is considered class A` (excellent) from Lake Washington to RM 4.1 (6.6 km) and Class AA' (extraordinary) from that point up to Landsburg, although class A designation may be violated for high temperatures in the lower reach. The river above Renton is characteristically cool and well -oxygenated, low in calcium and magnesium salts with a neutral pH (METRO, 1982). There is a METRO ambient monitoring station located at RM 9.3 (14.9 km) and the Cedar River water at that point meets all water quality standards for temperature, dissolved oxygen, turbidity, pH and several metals. Fecal coliform standards are occasionally exceeded and the copper chronic toxicity standard was also exceeded. King County (1993) speculated that the exceedence of the copper standard could be due to a natural metal content in the soils of the basin combined with the softness of the water which allows the metal to be more available; although it is not known what the baseline copper concentration is. King County (1993) sampled several locations in the Cedar for stormwater runoff and/or sediment quality in 1990 and 1991. Four stormwater sites were sampled from 1-405 to the mouth and five sediment sites: 1) ditch between Boeing Co. and Cedar River Trail park'; 2) Logan Bridge outfall'; 3) Bronson Way bridge 2; 4) 1-405 outfall'; 5) RM 0.75' (1200 m); 6) airport outfall'. The stormwater samples were taken during storm events and analyzed for pH, temperature, hardness, total suspended solids, turbidity, total phosphorus, nitrates, metals, oil/grease and fecal coliforms. Class AA waters: fecal coliforms <50 colonies/100 ml; temperature < 16 C; pH = 6.5-8.5; dissolved oxygen > 9.5 mg/I; and turbidity < 5 NTU. Class A waters: fecal coliforms < 100 colonies/100 ml; temperature <18 C; ph = 6.5-8.5; dissolved oxygen > 8.9 mg/I; turbidity <5 NTU. 5 1 = stormwater sampled only 2 = stormwater and sediment sampled 3 = sediment sampled only 33 The Logan Avenue outfall had very high turbidity readings (6-600 NTUs) and high fecal coliforms (1680-2500 colonies/100 ml). 1-405 outfall also had high fecal coliforms (10- 4600 range). All stormwater sites in the mainstem of the river exceeded the state AA class standards for fecal coliforms (standard = 50 colonies/100 ml). The outfalls also exceeded the copper, lead and zinc chronic and acute concentrations in several samples. Once again, metal toxicity is calculated based on water hardness and hence is greater in soft water and the standards can be exceeded even with low concentrations (range for Cu = 1-69 ppm, Pb = 0.8-238 ppm, Zn = 3-484 ppm). However, these concentrations could indicate a point source, such as an auto repair facility that has runoff to the Cedar River. Comparisons to sample locations further upstream show that runoff from Renton has more pollutant exceedences than runoff from more rural areas. The Corps placed a multiparameter water quality meter at the north Boeing bridge from February to early April, 1996. Turbidity readings reached extreme concentrations during the flood event in February 1996; up to 900 NTUs (5 NTUs is considered good water quality). The temperature and dissolved oxygen varied together, with temperatures ranging from 38 OF (3.47 IC) in mid February to 55 OF (13 °C) by early April, and dissolved oxygen ranging from 13.11 mg/I to 8.5 mg/I in late March. Water quality after this time period is assumed to be equal to Lake Washington. Lake Washington surface water temperatures can reach 75 OF (241 C) in the summertime. The Cedar River water is slightly cooler. 3.2.5 Wetlands King County has inventoried 892 acres of wetlands within the Cedar River basin (excluding the basin above Landsburg Dam, see Figure 14). Many of the wetlands are not associated directly with the Cedar River, although there is a large wetland area adjacent to Rock Creek, a major tributary to the Cedar. A number of wetlands (especially bogs and fens) are the headwaters of tributaries to the Cedar River. Along the mainstem Cedar River, there are many small riparian wetlands which are typically dominated by red alder (Alnus rubra), Oregon ash (Fraxinus latifolia), willows (Salix sp.), hardhack (Spirea douglash), and other species. 3.3 HABITAT The terrestrial environment in the project area is highly urbanized and provides limited wildlife habitat. The species present are able to adapt to the human environment and survive in an urban area. There is some limited riparian habitat which provides cover for waterfowl and some mammals. Approximately 25% of the river banks have overhanging vegetation; primarily 10-20 year old willows and alders. This habitat is limited to the right bank between Logan Avenue and the south Boeing bridge (approximately 2000 linear feet). The remaining 75% of the bank vegetation is 34 Legend Wetlands Cedar & tributaries Renton city limits -- Lakes Cedar basin wa Renton 0 MBIp woo! Falrwood Rattlesnake Lake ' dar Gro Desire Lake 'y ' R` Hobart Watsh i Tay to 4�' r Lake r"_.-- Spring Lake 1e" !� :._ Lake Morse .► AA Vu�Pey p r, _ J- rr \ % v 5 Lan urg ' nt Kangley,-. u vensdate m . } . } rr4 •r t•� y I N� w.� �:� Lake 1 edar River • t + Retreat N f `'� J 2 0 2 4 6 Miles r Sources River information obtained from Washington Rivers Information System (WARIS) database, Washington Department of Wildlife (WOW) and 1994 TIGER data, US Census Bureau. City boundaries• wetlands and additional data provided by King County. Wetland data is available for the lower basin only dominated by non-native species such as reed canary grass (Phalaris arundinacea), Himalayan blackberry (Rubus discolor and Japanese knotweed (Polygonum sachalinense), which provide some seasonal overhang and shading. Snag habitat is not available. The Audubon society has placed a few nesting boxes along the Cedar River trail park for cavity dwelling birds. The aquatic habitat is also highly modified and provides poor fish and invertebrate habitat over much of the lower mile. The river is channelized with armored banks. Anadromous salmon use the area primarily for a transportation corridor. Corps staff surveyed the lower 1.25 miles (2000 m) of the Cedar River using the Timber, Fish & Wildlife (NWIFC< 1994) stream survey methodology in 1994 and 1995. The lower mile of the Cedar is 77% riffle and glide habitat, 2% pool habitat and 20% Lake Washington backwater (at high pool). The small amount of pool habitat has a silt substrate and is restricted to bank scour areas. Depths range from 0.3-6.6 feet (10 cm- 2 m) over the reach, depending on gravel bar location and bank scour areas. During low flows at some transects, approximately 90% of the channel width was less than 0.66 feet (20 cm) depth. This can create difficulties for adult salmon migrating upstream. 3.4 FISH There are at least 22 species of fish in the Cedar River basin (see Table 1). Some of the species such as bull trout and pygmy whitefish are found only above the Masonry Dam in Chester Morse Lake. Other species, namely the torrent sculpin, are found in areas upstream of the project area in higher gradient portions of the river. 3.4.1 Salmon. (The following information is adapted from Groot & Margolis, 1991; Wydoski & Whitney, 1979 and other sources as noted.) As shown in Table 1, there are potentially eight different species of salmon found in the Cedar River. Bull trout is not likely in the river below Chester Morse Lake (one bull trout has been caught in the project area, but it has been speculated that it strayed in though the Locks; pers comm, E. Warner, MIT). Dolly Varden trout has not recently been observed in the Cedar River and its status is not known. Atlantic salmon have been infrequently captured in southern Lake Washington, but it is believed they are not successfully reproducing in the wild. Sockeye salmon are the most numerous salmon species in the river and in the Lake Washington basin as a whole. From yearly spawning surveys in the Lake Washington basin, it is estimated that approximately 80% of the sockeye population spawns in the Cedar River. Escapement estimates to the Lake Washington basin since 1972 have ranged from a high of approximately 531,000 in 1988 to a low of 24,000 in 1995, and the one population increase this year in 1996 with >350'0007. While the population has 'Trout are considered part of the salmon family, but in this document whitefish are considered separately even though they are officially salmonids. ' Escapement estimates based on Locks counts. 36 had dramatic swings in population it appears that the population overall is declining. In two of the last six years the escapement has been under 100,000. WDFWs target escapement to the Cedar River is 300,000 fish (350,000 to the entire Lake Washington basin). Table 1. Cedar River basin fishes and status, if known (from E. Warner, MIT). Common Name Scientific Name Status Sockeye salmon/kokanee Oncorhynchus nerka declining Chinook salmon O. tshawystcha declining Coho salmon O. kisutch declining Steel head/ra inbow trout O. mykiss declining Cutthroat trout O. clarki clarki increasing Dolly Varden trout Salvelinus malma rare Bull trout S. confluentus unknown, common in Chester Morse Mountain whitefish Prosopium williamsoni common Pygmy whitefish P. coulteri unknown, common in Chester Morse Atlantic salmon Salmo salar non-native Longfin smelt Spirinchus thaleichthys increasing (even year class) Northern squawfish Ptychocheilus oregonensis Peamouth chub Mylocheilus caurinus Three -spine stickleback Gasterosteus aculeatus abundant Largescale sucker Catastomus machrocheilus Longnose dace Rhinichthys cataractae Brook lamprey Lampetra richardsoni Torrent sculpin Cottus rhotheus Prickly sculpin Cottus asper Coastrange sculpin Cottus aleuticus Reticulate sculpin Cottus perplexus Yellow perch Perca flavescens non-native, increasing Brown bullhead Ictalurus nebulosus non-native Pumpkinseed sunfish Lepomis gibbosus non-native Smallmouth bass Micropterus dolomieui non-native, health Because of the observed decline in population, the Lake Washington Technical Committee was formed by the Washington Department of Fish & Wildlife (WDFW), with agency, academic, tribal and sport fish representatives to address issues surrounding sockeye salmon in the Lake Washington system. This group identified critical information which was needed before current and future management decisions are made. Based upon these needs, six studies were identified as vital to understanding the decline of sockeye salmon and became known as the Lake Washington Ecological Studies Program. Three of the six studies are expected to be completed over the next three years. There is still uncertainty over whether the sockeye and kokanee in the Lake Washington basin are partially descended from native stocks present before the Lake Washington ship canal and Locks were constructed; or, if the population is entirely 37 descended from Baker Lake stocks introduced beginning in 1937. Genetic testing of sockeye salmon in Bear Creek (Redmond, WA) indicate that particular run appears to be native. Sockeye fry and smolts have been planted from Baker and Cultus Lakes into the Lake Washington system for most years since 1937, and the Cedar River run is likely descended from those plants. The Cedar River, with 80% of the spawning sockeye population, is a critical habitat for both adults and emerging fry. Adults enter the system from late August through December. Adults need sufficient flows to enter the river and low temperatures (preferred range 45-58 OF or 7-14 °C) to survive to spawn. Habitats important for adults include pools to hold in and rest while moving upstream and spawning gravels with sufficient upwelling water to oxygenate the eggs. The movement of sediment bed load and deposition of fine materials can destroy spawning areas and eggs. Table 2 shows numbers of observed redds in the lower 1.25 miles (2000 m) of the Cedar River for the past three spawning seasons. WDFW typically conducts live salmon surveys from Landsburg down to RM 3 (4.8 km). In 1996, surveys were conducted down to 1-405 (RM 1.5 [2.4 km]) and 56% of this year's large run was counted below RM 5 (8 km). Historic adult distribution was fairly uniform over the 21 miles (34 km) of accessible mainstem. The WDFW survey data indicates that over the past several years, the upper river spawning population has declined (R. Egan, WDFW, pers. comm.) and greater than 50% of the run spawns in the lower 10 miles (16 km) of the river. It has been anecdotally observed that spawning gravels upstream of RM 10 (16 km) are too large for preferred spawning and the bulk of suitable gravel has moved into the lower river. Channelization and the removal of large woody debris (LWD) have likely exacerbated the scouring of smaller substrates from the channel. The estimated yearly gravel movement is only 1000 feet (300 m), therefore it has likely taken many years to "starve" the upper miles of their gravel (King County, 1993). It is not known if sockeye in recent years moved upstream and then returned downstream to spawn because the habitat was unsuitable, or if they never migrated upstream. Other factors may also be affecting sockeye migration, such as a lengthened time spent in the lake due to low flows in the early spawning season, difficulty of access into the upper reaches of the river, or delay from placement of the WDFW weir at RM 6 (9.6 km). Malick (1977) in his study of invertebrates populations did not observe any salmon spawning near his lowest sampling site at RM 3 (4.8 km). At the time of his study dredging was still occurring in the lower mile and the sediment upstream to perhaps RM 3 (4.8 km) may have been destabilized as a result of headcutting (the stream bottom most likely shifted noticeably to equalize the gradients between the dredged and undredged areas). The emerging fry migrate rapidly (typically in one night) down to Lake Washington under cover of darkness from late January through May. The peak of the outmigration is March and April. The fry are exposed to many predators, including rearing coho and steelhead, during their outmigration and typically have higher survival rates with higher flows. (Beauchamp, 1995; Martz, et al., 1996a & 1996b; Seiler, 1996) Predators can lurk in pool habitat (utilized by adult salmon in the fall) and in other backwater areas . Sockeye salmon spend the first year of life in Lake Washington, largely in deepwater areas. They feed primarily on zooplankton and insects. Table 2. Number of sockeye redds observed in the lower 1.25 miles (2000 m) of the Cedar River from 1994-1996. Survey Date Below 600 m 600-1000 m 1000-1300 m 1300-1700 m 1700-2000 m 11 /1 /94 0 0 2 23 99 11 /16/94 0 0 10 119 334 12/12/94 5 21 19 66 29 10/5/95 0 0 1 0 3 10/18/95 0 1 11 79 69 11/3/95 0 1 25 90 182 10/2/96 0 1 3 64 245 11 /1 /96 3 230 430 594 854 Naturally spawning chinook and coho salmon are present in smaller numbers in the Cedar River basin. The chinook escapement goal to the Cedar River is 2300 (1200 live count). Actual adult chinook counts in the Cedar River have ranged from 156-1752 (1993 was the lowest year on record, to date) over the past 30 years, based on live and redd counts (C. Smith, WDFW, pers. comm.). The population appears to be declining. Chinook fry emerge from the gravels from February through April and may rear for a short time in the river and then move into Lake Washington. Chinook fry have been captured in Lake Washington near the mouth of the Cedar River (Martz, et a11996a and 1996b). Puget Sound chinook stocks may be listed under the Endangered Species Act (16 U.S.C. 1531 et seq.) in the near future (WDFW, 1997). The wild coho escapement goal to the entire Lake Washington basin is 15,000. The actual escapement has varied from 30,000 in 1970 to 200 in 1994 (R. Eldrich, WDFW, pers. comm.). The Cedar River population is based on spawner index counts in some tributaries such as Rock Creek and counts have varied from 7700 in 1987 to 128 in 1994. Pacific coast coho have been petitioned for listing under the Endangered Species Act due to precipitous declines in many populations, including the Lake Washington population. Coho juveniles rear in stream habitats until they migrate out to sea approximately one year after emerging. Side channels, pools and areas with large woody debris are especially preferred for resting and overwintering habitat. Coho and chinook juveniles feed on insects, invertebrates and small fish. Steelhead trout are present in small numbers in the Cedar basin. Adult spawning populations in the mainstem of the Cedar have ranged from 900 in 1986 to 64 in 1994. 1994 was the lowest year on record. The Pacific Coast steelhead population (which includes the Lake Washington basin steelhead) has been petitioned for listing under the Endangered Species Act due to its precipitous decline in the last five years. Attention has been focused on the sea lions at the Locks preying on steelhead adults as they attempt to enter the fish ladder. However, the steelhead population was averaging approximately 1000 adults prior to the appearance of aggressive sea lions at the Locks. 39 Plants of steelhead/rainbow occurred until the 1990s. It appears that these plants did not bolster the steelhead population. A new supplementation program for steelhead is being planned by the WDFW, the Muckleshoot and Suquamish Tribes and Trout Unlimited that will use Cedar River broodstock to plant juveniles into north Lake Washington tributaries. Native adfluvial cutthroat trout and resident cutthroat are present in the Cedar River. Essentially nothing is known about the few searun cutthroat remaining in the Lake Washington basin. Small numbers of cutthroat are seen in the fish ladder at the locks, but no surveys have documented spawning locations in the basin. Supplemental cutthroat trout were first planted in the lake in 1914. The population of resident and/or adfluvial cutthroat appears to be increasing (Tabor & Chan, 1996), although exactly what factors are contributing to their increase is unknown. It has been speculated that cutthroat have replaced the niche formerly utilized by steelhead and possibly coho in tributary streams. Cutthroat smaller than 10 inches (250 mm) forklength (FL) feed largely on insects and small fish fry (such as larval smelt, sockeye and whitefish fry). Larger cutthroat feed almost entirely on larger fish such as longfin smelt and salmon smolts. Tabor & Chan (1996a) found cutthroat trout to have the highest consumption rates (highest among predator species sampled) of sockeye fry and presmolts. The population size of resident cutthroat in the lower Cedar River does not appear to be very large (Tabor & Chan, 1996a & b), based on low catch rates. Larger numbers (>100) have been captured, in continuing predator studies, by gill nets offshore of the Cedar delta in Lake Washington (E. Warner, MIT, pers. comm.). During late spring, cutthroat spawn in the Cedar River, but would not be expected to feed significantly during that time. Rainbow trout are resident in the Lake Washington basin and in the Cedar River. Hatchery rainbow are planted every year by the WDFW and other organizations (314,500 hatchery trout planted during spring of 1995) for sport fishing. Most of the hatchery plants do not survive more than one season in the lake. The Cedar River appears to have a healthy naturally spawning population of rainbow trout that utilize pool habitats over much of the system. Rainbow trout juveniles feed on aquatic insects, fish eggs, and small fish fry. Larger rainbows feed mostly on small fish, aquatic invertebrates, and insects. In the lower Cedar, rainbow trout also consumed moderate numbers of sockeye fry (Tabor & Chan, 1996a). Hatchery rainbow trout released before mid -May would have the opportunity to feed on sockeye fry; however, Tabor & Chan (1996a).found most hatchery trout to have consumed crustaceans and insects. 3.4.2 Longfin Smelt (also see Technical Appendices). Longfin smelt are perhaps the most abundant pelagic fish in Lake Washington. Current population estimates place the high year population at about 10 million fish. Longfin smelt in Lake Washington live for two years and spawn in their second year. The odd -year and even - year spawning populations have grown drastically apart in size, with the population that spawns in the winter/spring of even years being very large and the odd -year spawning population very small. It is unclear what led to this dramatic annual population difference, first noted by Moulton (1970). 40 Longfin smelt were not noted as present in early surveys of Lake Washington fish species. Smelt were first recorded in 1960. Edmundson & Abella (1988) have speculated that the population was too low to be detected by early sampling methods. It is unknown if smelt were anadromous into the Cedar River prior to the diversion of the Cedar into Lake Washington, or if a freshwater population had previously existed in the Lake. An anadromous run is still present in the Duwamish River. Now the smelt population in Lake Washington is entirely freshwater dwelling, spawning in streams and rivers (adfluvial). In the 1970s, Moulton (1974) documented smelt eggs in three other streams: May Creek, Juanita Creek and Coal Creek. Martz, et al (1996) found smelt eggs in May, Juanita, Coal and McAleer Creeks, but nonetheless estimated that greater than 90% of the smelt population now spawn in the Cedar River. Studies of smelt spawning in 1994, 1995 and 1996 have shown that smelt spawn in the lower portion of the Cedar River (Harza, 1994; Sibley & Brocksmith, 1996; Martz, et al, 1996). Sibley & Brocksmith (1996) did not find smelt eggs above 500 meters from the mouth, Martz, et al (1996) found 99% of the eggs below 900 meters (only 5 eggs found above that point). However, a significant number of eggs were captured by drift net at 900 meters, indicating that smelt do spawn further upstream but their eggs drift downstream. A few smelt larvae (5) were captured by Sibley & Brocksmith (1996) in a drift net at 1-405, which indicates that eggs were present above that location. Martz, et al (1996) found statistically significant negative correlations between egg abundance and substrate type, velocity and distance upstream from the mouth. Smelt appear to prefer sandy substrates in lower velocity areas not very far upstream from the mouth. Experiments conducted in aritificial stream habitats (Martz, et al, 1996) also showed smelt having a strong preference towards sandy substrates. Smelt appear to be weak swimmers and likely cannot swim very far upstream to spawn. Moulton (1970) found smelt eggs up to 1.25 miles (2000 m) above the mouth. However, at that time, the Cedar was periodically dredged to a depth of approximately 9 feet (2.7 m) below its current depth and the lake backwater extended approximately 1 mile (1600 m) upstream. Smelt fry (larvae) upon emergence are immediately carried downstream and out into Lake Washington to spend the next two years of their life in the pelagic zone. Smelt juveniles and yearlings forage largely for zooplankton and insects. Chigbu (1993) found that longfin smelt and sockeye salmon both prey on Daphnia sp. (a cladoceran) and may compete against one another for food. 3.4.3 Other Species. As shown in Table 1, there are 11 other species of fish that occur in portions of the Cedar River. Species that are known to occur in the project area include Coastrange sculpin, prickly sculpin, torrent sculpin, reticulate sculpin, largescale sucker, mountain whitefish, brook lamprey, yellow perch, brown bullhead, three-spined stickleback, smallmouth bass, pumpkinseed sunfish and northern squawfish (Corps, 1995; USFWS, 1995 and 1996). It is unknown if longnose dace occurs in the lower Cedar River. Many of these species are largely lake dwelling and utilize the lower portion of the river because the habitat is similar to Lake 41 Washington. Yellow perch, brown bullhead, sunfish and smallmouth bass are non- native species and have only been observed in small numbers in the river during the late spring and summer when the water temperatures are relatively high. Squawfish, suckers and whitefish spawn in the Cedar River (as do the resident sculpins) and on beaches in Lake Washington. It is not known if yellow perch or sticklebacks spawn in the river, but they certainly do spawn on Lake Washington beaches. Stickleback and the juveniles of many of these other species forage for invertebrates, zooplankton and insects. Larger squawfish and prickly sculpin also feed on small fish. Very few squawfish were captured by Tabor & Chan (1996) with nearshore equipment (electroshocking and beach seining). The few that were captured, generally had empty stomachs. It appears from limited sampling, that small cottids are the most important prey item for small squawfish (<250 mm). However, prickly sculpin can and do feed on sockeye fry as they migrate through the lower Cedar River and may be an important cause of mortality to sockeye (Tabor & Chan, 1995, 1996). Prickly sculpin prefer slower moving water with a sand or gravel substrate and are often in the open, particularly at night. Spawning occurs in April and May in areas with rock or log cover and slow water velocities. Prickly sculpin feed on fish eggs, small fish and invertebrates. The existing lower Cedar River backwater area appears to be excellent habitat for prickly sculpin. Three other sculpin species are found in the lower Cedar River: torrent, coastrange and reticulate sculpins (Tabor & Chan, 1996). These species are all typically found upstream of the lake backwater area. Torrent and coastrange sculpins prefer fast moving currents and gravel or cobble substrates. The young of both species are pelagic for a short time and then settle to the bottom and develop territories. Reticulate sculpins are smaller and may compete for food with torrent or coastrange sculpins of similar size. Reticulate sculpins are more frequently found in smaller streams or along the margins of large streams. All three species feed on aquatic insects, oligochaetes, fish eggs and small fish or fry. (Wydoski & Whitney, 1979) Tabor & Chan (1996b) found that prickly sculpins ate sockeye fry and adult longfin smelt on nights with high concentrations of these fish (hatchery releases or peak spawning nights). However, when fry or smelt were less available, their diet consisted mostly of aquatic insects, oligochaetes and fish eggs. Brook lamprey larvae were found during sediment sampling in 1994, by Corps staff. Nothing is known about their population size or distribution. 3.5 Aquatic Invertebrates Aquatic invertebrates in the Cedar River include many species of aquatic insects, worms and molluscs. The lower mile of the Cedar River was sampled three times in 1995 for generally surficial invertebrates (Sibley & Brocksmith, 1996b). Families sampled included Plecoptera (stoneflies), Ephemeroptera (mayflies), 42 Trichoptera (caddisflies), Diptera (true flies), Coleoptera (beetles), Megaloptera (alder flies), Arachnida (spiders), Crustacea (shrimp, etc.), Mollusca (clams, snails), Annelida (segmented worms) and Nematoda (roundworms). Higher velocity areas with gravel and cobble substrate generally had greater abundances of stoneflies and mayflies which prefer highly oxygenated, cool, swiftly running water. Lower velocity areas generally had greater abundances of crustaceans, molluscs, and worms which prefer slower moving waters and fine substrates. Dipterans (specifically Chironomidae) were found in both types of habitats. (Sibley & Brocksmith, 1996b) Previous work (Malick, 1977) in riffle areas upstream of the project area found Chironomidae to be the most dominant organisms in all sample areas, with mayflies, stoneflies and caddisflies with fewer numbers, but still important. Chinook, coho and steelhead rear for varying periods of time in the mainstem Cedar River and its tributaries. Their diet consists mostly of Chironomids, Plecopterans, Ephemeropterans, and Trichopterans as well as terrestrial insects. These species are typically found in higher velocity waters. Near the mouth of the river, coho and steelhead juveniles feed on fish fry and insects. 3.6 Wildlife The upper Cedar River watershed is noted for the large number of wildlife species as well as their abundances. Black bear, elk, black -tailed deer, cougar, mink, muskrat, bobcat, coyote, mountain goat, racoon, and various small mammals are all resident in the upper watershed. In the urbanized project area, however, the wildlife species are typical of parks around Lake Washington. Mammals such as Eastern gray squirrels, opossum, raccoon, muskrat, beaver, cottontail rabbits, striped skunk, Norway rats, mice and domestic dog and feral cat species commonly occur in the lower Cedar River and adjacent park (COE, 1995). Birds and waterfowl are quite numerous in the project area, due to the good river and lake habitat. U.S. Fish & Wildlife Service (USFWS) and Corps biologists have observed over 50 species of birds in the lower mile (1600 m) of the Cedar and on the delta and adjacent Lake Washington waters during studies in 1994-1996 (see Table 3). 3.7 Threatened and Endangered Species. Bald eagle (Haliaeetus leucocephalus) is the only federally listed species that occurs it the project area. It is listed as threatened in Washington state. There are four species of fish which are candidates for listing under the Endangered Species Act (PL ) that may occur in the project area: Puget Sound stocks of chinook salmon (Oncorhynchus tshawytscha), sockeye salmon (O. nerka), coho salmon (O, kisutch) sea -run cutthroat trout (O. clarki clarki), and steelhead trout (O. mykiss) are under review with chinook most likely to be listed in the near future. Chinook, coho and sockeye salmon and steelhead and sea run cutthroat trout occur in the Cedar River as described in Section 3.4.1. The status and location of sea -run cutthroat trout in the Lake Washington basin 43 is not known. Two species of concern may occur in the project area, northwestern pond turtle (Clemmys marmorata marmorata) and the river lamprey (Lampetra ayresi). Table 3. Birds observed in vicinity of lower Cedar River (Stagner, 1995; Brunner, 1995) Western grebe Horned grebe Double -crested cormorant Canada goose Mallard' Scaup spp. teal' Buff lehead Common merganser` -Green-winged Hooded mer anserz Gadwall' Northern shoveler Canvasback Common goldeneye Barrow's oldene e' Great blue heron' American coot Bald eagle' Western sandppiper Glaucous -winged gull Killdeer California gull Ring -billed gull Herring gull Tha er's gull Mew gull Rock dove woodpecker' Barn swallow Rough -winged swallow -Hairy swallow' Cliff swallow Tree swallow' -Violet-green American crow' Black -capped chickadee' Chestnut -backed chickadee' Common bushtit' American robin' Eurasian starling' House finch' Yellow warbler' Yellow -rum ed warbler' Houses arrow' Dark -eyed junco' Red -winged blackbird' Rufus -sided towhee' Common ellowthroat' Song sparrow' White -crowned sparrow' Golden -crowned sparrow' Belted kingfisher' hawk' Wilson's warbler' Downy woodpecker' -Cooper's Vaux's swift Brown -headed cowbird' Americangoldfinch' -Ruby-crowned kinglet' Bewick's wren' 1. Frequently use or require riparian vegetation. 2. Use riparian vegetation, but prefer large trees or dead snags for perching and nesting. Bald eagles typically migrate to wintering ranges in Washington state in late October and the nesting season extends from January through August 15. Year-round resident bald eagles are known to be in the greater Seattle area. The nearest known nest, to the project area, is located in Seward Park, approximately 3 miles northwest. Bald eagles have been observed using the woody debris at the Cedar River delta and perching on adjacent Boeing property and at Gene Coulon Park (USFWS, 1995 and 1996). No foraging behavior has been documented, but the eagles were likely in the area to prey on salmon carcasses or waterfowl near the delta. A survey is currently being conducted to determine if northwestern pond turtles occur in the project area. It is unlikely that any still exist in the area of Lake Washington. The WDFW supports a captive breeding program at the Woodland Park Zoo in Seattle which will attempt to reintroduce northwestern pond turtles to selected western Washington locations, including Lake Washington. The only habitat expected to be suitable for northwestern pond turtles, in the project area, is the logs and other debris on the delta. It is unknown if river lamprey are in the, Cedar River. 44 3.8 Veaetation. Riparian vegetation in the upper Cedar watershed consists of a mix of second growth deciduous and coniferous trees and a number of native shrub species. Species include black cottonwood (Populus balsamifera), willows (Salix sp.), red alder (Alnus rubra), western hemlock (Tsuga heterophylla), western red cedar (Thuja plicata), Douglas fir (Pseudotsuga menziesh), bigleaf maple (Acer macrophyllum), red osier dogwood (Corpus stolonifera), snowberry (Symphoricarpus alba), red elderberry (Sambucus racemosa), Indian plum (Oemlaria cerasiformis), ninebark (Physocarpus capitatus) cascara buckthorn (Rhamnus purshiana), salal (Gaultheria shallon), devil's club (Oplopanax horridum), salmonberry (Rubus spectabilis) and Oregon grape (Berberis nervosa). The project reach is highly urbanized and has very few native species present. The left bank has an airport access road approximately 10 feet (3 m) from the river bank, so has very limited room for riparian vegetation. The airport has also mowed down the vegetation along the lower 1000 feet (300 m) of the left bank because of the close proximity of the runway and the need for a "clear zone". The only section of native vegetation along the left bank is a strip of approximately 5 cottonwood trees and scattered willows and alders located between Logan Avenue and the south Boeing bridge for approximately 1000 feet (300 m). The right bank is a city park and has some native species and many ornamental or otherwise exotic species. The predominant riparian species are red alder, Himalayan blackberry (Rubus discolor, Japanese knotweed (Polygonum sachalinense), willows and reed canary grass (Phalaris arundinaceae). The alders and willows are in a narrow strip (one tree wide) along the upper reach of the project area for approximately 1700 feet (515 m), upstream of the south Boeing bridge. On the right bank below the south Boeing bridge there are no areas of native vegetation except for a few (<10) alders and willows scattered along the bank. The riparian zone is dominated by blackberries and reed canary grass. Mowed lawn also occurs up to the bank edge in many locations. There are approximately 8 weeping willow trees adjacent to and downstream of the boat ramp. Aquatic vegetation is present in the lowest 1650 feet (500 m) of the river. Observations by COE staff identified the species present as waterweed (Elodea canadensis), eelgrass pondweed (Potamogeton zosteriformis) and curly pondweed (Potamogeton crispus). These species are all growing in 3-6 feet (0.9-1.8 m) of water which is influenced by the summer.lake level and experiences very slow current velocities. It is estimated that approximately 20,000 square feet of native riparian vegetation exist along the lower 1.25 miles of the river. 45 3.9 Cultural Resources The lower Cedar River/Black River/Lake Washington area was historically occupied by the Duwamish Indians. The Duwamish, and at least eight other closely related Southern Puget Sound tribal groups, belong to the Coast Salish language group. These tribes were skilled fishermen, hunters and plant collectors. People aggregated into large villages during the winter months; during the spring, groups tended to disperse into smaller units for exploitation of locally available resources. Salmon runs in the Duwamish, Black and Cedar Rivers were an important resource to the Duwamish Indians. The Duwamish were party to the Treaty of Point Elliott signed in 1855, which ceded Indian lands to the United States and removed various Puget Sound tribes to established reservations in western Washington. The Muckleshoot Indian Tribe is the recipient of the Point Elliott treaty rights as heirs of the various tribes which moved to the reservations. As partial compensation for ceding lands to the U.S. government, the signing tribes were granted the right to continue to take fish at usual and accustomed fishing grounds. On the old Black River, there are several sites associated with the Duwamish Indians. These sites have been excavated and described per previous development in the southwest portion of Renton. The first record of Euro-American settlement in the area was the establishment of a saw mill on the Black River in the early 1850s. The first post office was constructed at the junction of the Black and Cedar Rivers in 1867. The City of Renton was named for Captain William Renton who originally settled in the Puget Sound area in 1853 for the timber industry. In his search for timber, Renton located a large vein of coal near the present City of Renton and subsequently started the Renton Coal Company. When the town was platted in 1876, it was named after Renton and its first large industry. In 1877, the first railroad reached the City of Renton which facilitated shipment of coal to west coast cities. Expansion of the railway system was also conducive to increased homesteading in the area throughout the 19th and early 20th centuries. During the winter of 1910-1911 extensive flooding along the Cedar River caused the citizens of Renton to form Waterway District No. 2 which was responsible for excavating a new channel to contain the "wild" river. This new channel project coincided conveniently with the Corps' Lake Washington Ship Canal project which lowered Lake Washington by 9 feet and required a new input of fresh water to operate the locks for navigation. No historic sites are located within the project area that are eligible for the National Register of Historic Places. 3.10 Land Use/Recreation/Public Use The property surrounding the lower Cedar River is largely urban industrial, with the Boeing manufacturing plant on the east side of the river and the Renton Municipal Airport on the west side. The airport's seapland launch/dock area is adjacent to and west of the airport runway. The Renton Airport is used extensively by small planes and ER Boeing and is the fifth busiest airport in Washington. The airport bank overflows at approximately 2500 cfs, currently. This causes flooding of the airport perimeter road every winter. During higher flows, airport buildings and the runway are inundated with water. A significant recreational feature, the Cedar River Trail Park is alongside the right bank of the Cedar River with a narrow strip park area from the Logan Avenue bridge to the mouth, and a trail only, upstream of the Logan Avenue bridge to the Renton library. A non -motorized boat launch area is present in the park. Upstream of the Boeing plant is the Renton School District stadium and parking area. Above Logan Avenue, there are a number of municipal buildings including City Hall and the public library adjacent to the river. Fishing for salmon or steelhead is not allowed in the Cedar River. Several portions of the Cedar River Trail flood during most winter flows, with existing conditions. This creates a public safety hazard and reduces public access to the riparian area. 3.11 Transportation The lower two miles (3.2 km) of the Cedar River are crossed several times by roads within the City of Renton (see Figure 2). Immediately adjacent to the lower mile of the Cedar River is the Cedar River Trail Park (right bank) which has access through the Boeing manufacturing facility. A small non -motorized boat ramp is located within the Park. The left bank is occupied by the City of Renton Municipal Airport, with an adjacent seaplane launch in Lake Washington. Public access is allowed on a road from Logan Avenue down to the south Boeing bridge. Access is controlled beyond that point for airplane owners and airport personnel only. During most winters, the perimeter road along the left bank of the river is flooded. The two Boeing bridges are Boeing property and utilized for transporting planes across the river. Boeing transports several planes a day across their bridges for testing and other manufacturing requirements. Without these bridges, Boeing would not be able to fly its planes out of the Renton facility. Flooding has frequently caused the south Boeing bridge to accumulate large quantities of debris, which must be removed in order to prevent failure of the bridge during high flows. Cleanup and maintenance is extensive at the bridge and the surrounding areas after flooding. Other current hazards to transportation, in the project area, include the large numbers of gulls and geese that utilize the gravel bars in the river, the delta, the park and the airport runway area for resting. These birds have been struck by aircraft taking off and landing at least several times, although the actual number is unknown. The airport typically clears the runway of birds prior to Boeing jet take -offs to reduce the likelihood of bird strikes. The City dredged the delta in 1993, primarily to eliminate habitat for 47 these birds. However, monitoring conducted after dredging (Harza, 1995) indicated that the birds simply moved onto the runway or park rather than leaving the area. 3.12 Air/Noise/Light Air quality in the City of Renton was formerly classified as "nonattainment" for carbon monoxide (CO) and ozone. All other parameters were within the attainment category. In 1996, most of the Puget Sound region (including Renton) was reclassified as "attainment" because only infrequent violations of air quality standards occurred in the previous five years. (PSAPCA, pers. comm.) In the area surrounding the lower Cedar River, possible sources of pollution would be airplane fuels and exhaust and car and truck exhaust. Noise in the area surrounding the lower Cedar River is periodically quite high (88-98 dB) during full power engine testing. Boeing performs engine testing several times per day, and each test may last 40 minutes (M. Nakjiri, Boeing, pers. comm), however most of the testing period is at lower engine levels. The airport has small to large aircraft landing or taking off an average of 400-500 times per day; and two Boeing jets typically take off per day under the current manufacturing schedule. The annual average noise exposure at the Cedar River and portions of the Cedar River Trail Park is 60-65 dB (Bucher, Wllis & Ratliff, 1995). 3.13 Aesthetics The lower Cedar River is surrounded by urban -industrial development and this is obvious to anyone walking along the Cedar River Trail. The park and trail and adjacent Cedar River create a natural aesthetic refuge from the surroundings. The existing vegetation creates a shady and protected zone. Views from the park include the Boeing facilities, airport, lower River and Lake Washington with territorial views to Seattle and Mercer Island. 3.14 Public Service/Utilities/Energy Utility and sewer lines are present along both sides of the lower Cedar River and utility lines cross the south Boeing bridge. Boeing has internal storm drains that are currently buried beneath Cedar River sediments. Boeing is in the process of rerouting all stormwater drainage into one outfall with an oil/water separator that drains into Lake Washington. The airport also has several storm drains that are currently buried beneath Cedar River sediments. 3.15 Public Health and Safety The public uses the Cedar River Trail park as described in Section 3.10. Public health and safety concerns occur during normal winter flows in the Cedar River, when the trail is inundated with -water at the Logan Avenue bridge and upstream. Public health and safety are also threatened by flood flows which inundate the road along the left bank ff: (airport) and much of the Cedar River Trail park. The current flooding situation can cause the backup of sewage and other contaminants into areas of human use. The flood fighting required to prevent loss of the south Boeing bridge during a flood is also very hazardous. The airport has several storm drains that feed into the Cedar River; these drains have become sedimented over and during flooding the drains cause internal flooding on the airport because they do not drain. 49 4. ENVIRONMENTAL IMPACTS This section describes and evaluates the environmental impacts of the five alternatives described in Section 2.2. The impacts from each alternative are evaluated side by side under each element of the environment. Efforts to avoid and minimize impacts which shaped the proposed alternatives are also described under each element of the environment. The minimal dredge alternative (4 feet) is the Corps' and local sponsor's preferred alternative based on economic and environmental considerations. However, the impacts from all action alternatives have been evaluated in detail because there was interest on the part of the sponsor in pursuing the moderate dredge (6 feet) alternative during the draft EIS phase. These impacts have been left in the final EIS to provide additional information. 4.1 Geology/Sediments/Soils/Floodplains No alternatives will have an adverse impact on geology. None of the action alternatives will change floodplain management plans or objectives or increase floodplain development, because the purpose of flood control is to protect the existing highly developed urban area of Renton. 4.1.1 No Action Alternative With the no -action alternative, sediments will continue to be transported downstream by the Cedar River and will deposit in the lower mile and delta at a rate of 0.1-1.0 foot/year (0.03-0.3 m/year). Corps' hydraulics modeling indicates that in less than 20 years in the future, the channel will fill in to the point that the majority of the River flow would avulse onto the Renton airport. A more likely future scenario is that flooding would become so intense in the City of Renton that emergency dredging would occur at some point in the near future and prevent the river from completely avulsing onto the airport. The existing and future flooding situation can cause the deposition of greater than 5000 cubic yards of sand and other material onto the Renton airport access road and the Cedar River Trail Park. 4.1.2 Existing Channel Alternative The existing channel alternative would require a minimal amount of dredging to remove existing gravel bars in the lower mile to create a uniform depth across the channel equal to the existing thalweg depth. A total of 31,000 CY of material would be removed. The sediment size distribution would not be changed from the existing distribution because the underlying sediment is similar to the exposed sediment. Immediately after dredging, the sediments should be less embedded or "armored" with fine materials because the dredging will disturb fine materials. Between maintenance dredge cycles, sediments would continue to be deposited in the same manner as now. In the range of 0.1-1.0 foot/year (0.03-0.3 m/year) of sediments would be deposited. Continued maintenance dredging would be required approximately every 3 years, with 114,000 CY of material, on average, removed. The short-term maintenance dredging 50 impacts will be virtually identical to the short-term initial construction impacts if similar methods of dredging are used (primarily related to water quality, see Section 4.2). The lake backwater would remain in the same location, from the mouth up to - 1000 feet (300 m) upstream (during high lake level). The existing channel depth alternative will not adversely affect sediments or soils in the lower Cedar River. 4.1.3 Minimal Dredge Alternative (Preferred Alternative) The minimal dredge alternative would require dredging an average of 4 feet (1.2 m) of the existing sediments from the north Boeing bridge (mouth) up to Logan Avenue and then sloping up to meet the existing gradient approximately 800 feet (240 m) upstream of Logan Avenue at Williams Avenue. A total of 158,000 CY of material would be removed. The sediment size distribution would not be changed from the existing distribution because the underlying sediment is similar to the exposed sediment. Immediately after dredging, the sediments should be less embedded or "armored" with fine materials because the dredging will disturb fine materials. Between maintenance dredge cycles, sediments would continue to be deposited in a similar manner as now, except the lake backwater would extend from the mouth up to approximately 3300 feet (1000 m) upstream of the mouth; an increase of 2300 linear feet (700 m) (increase of 253,000 ft2 [5.8 acres or 23,230 m2]). The area influenced by the lake backwater would tend to accumulate fine sediments such as sands and silts during low -moderate flows. These finer sediments are found as layers on top of gravel which is deposited during high flows. The minimal dredge alternative will increase the area of gravel embedded with fine sediments (during the summer high lake level) by approximately 253,000 ft2 (5.8 acres or 23,230 m2), and concomitantly decrease the area of clean small to large gravel by an equal amount. Continued maintenance dredging would be required, conservatively, every 3 years, with 170,000 CY of material, on average, removed. The short-term maintenance dredging impacts will be virtually identical to the short-term initial construction impacts if similar methods of dredging are used (primarily related to water quality, see Section 4.2). 4.1.4 Moderate Dredge Alternative The moderate dredge alternative would require dredging an average of six feet of existing sediments from the mouth up to Logan Avenue and then sloping up to meet the existing gradient approximately 1200 feet (360 m) upstream at Wells Avenue. A total of 195,000 CY of material would be removed initially. The sediment size distribution would not be changed from the existing distribution because the underlying sediment is similar to the exposed sediment. Immediately after dredging, the sediments should be less embedded or "armored" with fine materials because the dredging will disturb fine materials. Between maintenance dredge cycles, sediments would continue to be deposited in a similar manner as now, except the lake backwater would extend from the mouth up to approximately 4200 feet (1300 m) upstream; an increase of 3200 linear feet (1000 m) (an increase of 352,000 ft2 [8 acres or 32,320 m2]). The area influenced by the lake backwater would tend to accumulate fine sediments such as sands and silts during low -moderate flows. These finer sediments are found as layers on top of gravel 51 which is deposited during high flows. The moderate dredge alternative will increase the area of fine sediments (during the summer high lake level) by approximately 352,000 ft2 (8 acres or 32,320 m2), and concomitantly decrease the area of small/large gravel by an equal amount. Continued maintenance dredging would be required, conservatively, every 3 years, with 176,000 CY of material, on average, removed. The short-term maintenance dredging impacts will be virtually identical to the short-term initial construction impacts if similar methods of dredging are used (primarily related to water quality, see Section 4.2). 4.1.5 Deep Dredge Alternative The deep dredge alternative would require dredging an average of ten feet of existing sediments from the mouth up to 4900 feet (1700 m) upstream and then sloping up to meet the existing gradient approximately 1200 feet (360 m) upstream of Logan Avenue at Wells Avenue. A total of 260,000 CY of material would be removed initially. The sediment size distribution would not be changed from the existing distribution because the underlying sediment is similar to the exposed sediment. Immediately after dredging the sediments should be less embedded or "armored" with fine materials because the dredging will disturb fine materials. Between maintenance dredge cycles, sediments would continue to be deposited in a similar manner as now, except the lake backwater would extend from the mouth up to approximately 5600 feet (1700 m) upstream; an increase of 4600 linear feet (1400 m) (an increase of 506,000 ft2 [11.6 acres or 46,460 m2]). The area influenced by the lake backwater would tend to accumulate fine sediments such as sands and silts during low -moderate flows. These finer sediments are found as layers on top of gravel which is deposited during high flows. The deep dredge alternative will increase the area of fine sediments (during the summer high lake level) by approximately 506,000 ft2 (11.6 acres or 46,460 m2), and concomitantly decrease the area of small to large gravel by an equal amount. Continued maintenance dredging would be required approximately every 3 years, with 185,000 CY of material, on average, removed. The short-term maintenance dredging impacts will be virtually identical to the short-term initial construction impacts if similar methods of dredging are used (primarily related to water quality, see Section 4.2). 4.2 Water and Water Quality For all dredging alternatives, during construction and maintenance, there will be an short-term increase in turbidity. All practicable best management practices will be utilized to minimize turbidity. The lowest 3000 feet (900 m) will be dredged by a barge mounted clamshell, dragline or hydraulic suction dredge. Silt curtains will be employed in this area of lake backwater to contain turbidity during dredging. Return water will flow out of the dredged sediments either on the park (where best management practices such as the use of hay bales will reduce turbidity) or from a barge. The upstream area which cannot be dredged by barge will be dredged by one of the methods described in Section 2.2. Dredging by a crane mounted clamshell will have significant turbidity increases because fine materials will wash out of the clamshell with 52 the water. Silt curtains would not be feasible in this reach of the river because of the velocities and potential for trapping fish. Dredging by front-end loader (river diverted by use of coffer dams) would not cause any significant turbidity because the river would be diverted away from the immediate dredging area. Even during rain events, the dredging area for a front-end loader will be isolated from the river by coffer dams and there should not be any significant increase in turbidity because the stormwater will percolate into the sediments. Additionally, for all action alternatives, four supports to hydraulically jack the south Boeing bridge will be constructed partially in the channel. The steel jacking structure will be placed down in the sediments by a crane -mounted augering device. The auger will be incased in a steel pipe to contain all sediments excavated during augering and these sediments will be removed to the upland. A concrete retaining wall will be constructed around each of the steel supports to prevent water contact except during high flows. During construction of these retaining walls, coffer dams will be placed around the area to prevent contact of water with uncured concrete. Any water which seeps into the coffer dammed area will be pumped out and removed from the site. 4.2.1 No Action Alternative In the short term, the no action alternative will not significantly change existing water or water quality. The current water quality is endangered whenever flood flows go across the urbanized areas of Renton and wash pollutants into the Cedar River and Lake Washington. As the sediment aggrades in the channel, in less than 20 years in the future, the main river flow will likely avulse onto the Renton airport. Prior to avulsion, velocities would likely increase as the channel became higher than the lake level. When the channel did avulse, velocities would be reduced as the water spreads out over the unconfined runway. This would worsen the effects on water quality as oils and grease on the roads and runway were dissolved or suspended in the river flow. Utility lines such as natural gas or sewage would be in danger of breaking from overbank flooding and erosion. Other existing water quality problems, such as high temperatures in the summertime would not change or may become worse as the channel filled in and the river spread out shallowly over a greater area. 4.2.2 Existing Channel Alternative Construction effects on water and water quality are described above. After construction, the existing channel alternative will not affect water or water quality. Velocities will remain similar to now. The thalweg, which currently meanders somewhat between gravel bars will be in the center of the channel. Water quality will not be changed from the existing condition except for short-term turbidity effects during construction and maintenance dredging. 53 1 4.2.3 Minimal Dredge Alternative (Preferred Alternative) Construction effects on water and water quality are described above. After construction, the minimal dredge alternative will not adversely affect water quality. Velocities will be reduced in the area of increased lake backwater. The dredged channel will be V-shaped and tend to concentrate river flow in a narrower area than exists now. The river flow during low flow periods (June -September) may be deeper than the existing condition with slightly increased velocities. 4.2.4 Moderate Dredge Alternative Construction effects on water and water quality are described above. After construction, the moderate dredge alternative will not adversely affect water quality. Velocities will be reduced in the area of increased lake backwater. The dredged channel will be V-shaped and tend to concentrate river flow in a narrower area than exists now. The river flow during low flow periods (June -September) may be deeper than the existing condition with slightly increased velocities. 4.2.5 Deep Dredge Alternative Construction effects on water and water quality are described above. After construction, the moderate dredge alternative will not adversely affect water quality. Velocities will be reduced in the area of increased lake backwater. The dredged channel will be V-shaped and tend to concentrate river flow in a narrower area than exists now; however, the lake backwater will extend to Logan Avenue and velocities will still be much reduced over the entire length of the lower mile. 4.3 Fish Because most of the work proposed for this project involves some level of dredging, with continued maintenance, potential impacts on fish and fish habitat were considered to be very important during scoping. Efforts to minimize negative impacts on fish, from the dredging alternatives, include: (1) construction and maintenance will only occur from June 15 - August 31 (a reduction from the usual work window of June 15- September 15) when salmon species are not typically present in the project area. Smelt spawning and fry emergence occurs prior to June 15. (2) The actual time period of construction and maintenance dredging will be compressed within the work window, if feasible, to avoid prolonged disturbance to resident fish such as sculpin and trout. 4.3.1 Sockeye Salmon 4.3.1.1 No Action Alternative The no action alternative will not immediately change the existing conditions for sockeye salmon. As the channel sediment aggrades, the reach below the south Boeing bridge would likely experience slightly increased water velocities as the channel bottom 54 becomes higher above the lake level and reduces the lake backwater effects. Once the channel became nearly filled in and the river flow spreads out into the adjacent park and airport, the effects on sockeye salmon would be very negative. It would be very difficult for adult sockeye to transit into the lower portion of the river because depths would be dramatically reduced and river temperatures would increase. During flooding the potential for stranding both adults and juveniles on the airport and other areas would be increased. Likewise, juvenile salmon would more easily be washed out onto the airport during high winter and spring flows experiencing stranding or contact with pollutants. The no action alternative is likely to have significant negative impacts on sockeye salmon in the future. 4.3.1.2 Existing Channel Alternative The existing channel alternative will modify the channel cross-section by removing existing gravel bars and deep holes. This will create a uniform depth across the channel which may reduce water depths. The reduced water depths may make it more difficult for adult sockeye salmon to ascend the lower Cedar River during low flows (--200 cfs). The existing depths at low flows already may hinder access by adult salmon. Conditions for juvenile sockeye salmon would not be significantly different from the existing situation. The levees and floodwalls will be protected as described in Section 2.2 with riprap below the OHWM for approximately 400 feet (120 m). This may provide new habitat for predator species such as cutthroat and rainbow trout or rearing juvenile salmon of other species such as coho or steelhead (reference Tabor & Chan, 1996a and 1996b; Beauchamp, 1995; which indicates that coho and steelhead juveniles prey on sockeye fry in the lower Cedar River). The riprap may also provide some additional holding areas for adult sockeye salmon during their ascent in higher flows. Spawning substrate will not be affected because the removal of gravel bars will not remove below water gravel spawning areas; however, water depths and velocities may be slightly reduced. Overall, the existing channel alternative will slightly hinder access for adult sockeye salmon during low flows and will slightly increase habitat for predator species that prey on sockeye fry. 4.3.1.3 Minimal Dredge Alternative (Preferred Alternative) The minimal dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The lake backwater will extend from the mouth up to 3300 feet (1000 m) upstream. Access for adult sockeye salmon will be enhanced slightly during low flows over the existing conditions. The levees and floodwalls will be protected as described in Section 2.2 with riprap below the OHWM for approximately 400 linear feet (120 m). This may provide new habitat for predator species such as cutthroat and rainbow trout or rearing juvenile salmon of other species such as coho or steelhead (reference Tabor & Chan, 1996a and 1996b; Beauchamp, 1995; which indicates that coho and steelhead juveniles prey on sockeye fry in the lower Cedar River). The riprap may also provide holding areas for adult sockeye salmon during their ascent in higher flows. The lake backwater area will be increased by 253,000 feet' (5.8 acres or 23,230 55 m') and will provide additional habitat for potential predator species that prefer a lake - like environment, such as northern squawfish, yellow perch, largemouth bass and trout species. As described in Section 3.4, these species are not typically present during the sockeye fry outmigration period and are not expected to substantially reduce sockeye fry survival in the lower Cedar River, even though their habitat may be increased during late spring and summer. Prickly sculpin habitat will be increased and they may be more significant predators on sockeye salmon fry than other lake dwelling species. It is expected that prickly sculpin populations will be periodically reduced due to maintenance dredging. Sockeye spawning habitat will be somewhat reduced. A maximum of 235 redds have been observed below 1000 meters (0.15% of the run). This habitat will become lake backwater and will be unsuitable for spawning, however, the gravel substrate above 3300 feet (1000 m) will remain similar to the existing condition after dredging, with slightly changed depths. Overall, adult transport and spawning in the project reach will be reduced. Sockeye fry survival will likely be reduced by the increase of predator habitat. 4.3.1.4 Moderate Dredge Altemative The moderate dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The lake backwater will extend from the mouth up to approximately 4200 feet (1300 m) upstream. Access for adult sockeye salmon will be enhanced slightly during low flows over the existing conditions. The levees and floodwalls will be protected as described in Section 2.2 with riprap below the OHWM for approximately 400 linear feet (120 m). This may provide new habitat for predator species such as cutthroat and rainbow trout or rearing juvenile salmon of other species such as coho or steelhead (reference Tabor & Chan, 1996a and 1996b; Beauchamp, 1995; which indicates that coho and steelhead juveniles prey on sockeye fry in the lower Cedar River). The riprap may also provide holding areas for adult sockeye salmon during their ascent in higher flows. The lake backwater area will be increased by 352,000 feet' (8 acres or 32,320 m') and will provide additional habitat for potential predator species that prefer a lake -like environment, such as northern squawfish, yellow perch, largemouth bass and possibly trout species. As described in Section 3.4, these species are not typically present during the sockeye fry outmigration period and are not expected to substantially affect sockeye fry survival in the lower Cedar River, even though their habitat may be increased during late spring and summer. Prickly sculpin habitat will be increased and they may be more significant predators on sockeye salmon fry than other lake dwelling species. It is expected that prickly sculpin populations will be reduced by periodic maintenance dredging. Sockeye spawning habitat will be reduced. A maximum of 665 redds have been observed below 4200 feet (1300 m) upstream of the mouth (0.44% of the run). This area will become lake backwater and will be unsuitable for salmon spawning. However, the gravel substrate above 4200 feet (1300 m) will remain similar to the existing condition after dredging, with slightly altered depths and velocities. 56 Overall, adult transport and spawning in the project reach will be reduced. Sockeye fry survival will also be reduced by the increase of predator habitat. 4.3.1.5 Deep Dredge Alternative The deep dredge alternative will narrow the existing channel bottom (because of the v- shape) and will increase water depths from the mouth up to Logan Avenue. Velocities will be reduced in this reach because the lake backwater will extend up to approximately 5600 feet (1700 m) from the mouth. This will cause the lower mile of the river to be essentially part of Lake Washington during high pool levels (spring and summer). Access for adult sockeye salmon may be slightly enhanced, during low flows, over the existing condition. The lake backwater area will be increased by 506,000 feet' (11.6 acres or 46,460 m') and will provide additional habitat for potential predator species that prefer a lake -like environment, such as northern squawfish, yellow perch, largemouth bass and possibly trout species. Prickly sculpin that currently utilize the lake backwater habitat will have significantly more habitat. Prickly sculpin may be the most significant predator on sockeye fry (Tabor & Chan, 1996). It is expected that prickly sculpin populations will be periodically reduced by maintenance dredging, but with such a large increase of available habitat their populations will likely increase significantly. The riprap protection for the levees and floodwalls will be in the lake backwater and habitat for other predators would not likely be increased above that caused by the backwater effect. A maximum of 1259 redds have been observed in the area from 5600 feet (1700 m) down to the mouth (0.8% of the run). The spawning habitat ranges from poor to good, it is not known what the overall survival of eggs or fry is in this area, but the lower mile is approximately 4% of the total mainstem area. Overall, sockeye spawning habitat may be reduced by as much as 4%. Sculpin and other predator habitat will be increased significantly with the increased lake backwater area and will likely significantly reduce sockeye fry survival. 4.3.2 Chinook Salmon 4.3.2.1 No Action Alternative The no action alternative will not immediately change the existing conditions for chinook salmon. As the channel sediment aggrades, the reach below the south Boeing bridge would likely experience slightly increased water velocities as the channel bottom becomes higher above the lake level. Once the channel became nearly filled in and the river flow spreads out into the adjacent park and airport, the effects on chinook salmon would likely be very negative. Adult chinook would have a more difficult time ascending the lower portion of the river because depths would be dramatically reduced and during higher flows the potential for stranding of adults or juveniles on the airport and other areas would be increased. Likewise, juvenile salmon would more easily be washed out onto the airport during high winter and spring flows experiencing stranding or contact with pollutants. The no action alternative is likely to have significant negative impacts on chinook salmon in the future. 57 4.3.2.2 Existing Channel Alternative The existing channel alternative will modify the channel cross-section by removing existing gravel bars and deep holes. This will create a uniform depth across the channel which may reduce water depths. The reduced water depths may make it more difficult for adult chinook salmon to ascend the lower Cedar River during low flows (-200 cfs). The existing depths and high temperatures at low flows already likely delay access or create additional stress for adult salmon. Spawning habitat for adult chinook would not be changed from the existing condition. Only sporadic spawning occurs in the project area. Chinook would be more affected by water depths than other species because their run timing is typically earlier, during low flow periods. No significant holding habitat exists in the lower river for adults migrating further upstream. Some chinook fry appear to migrate to Lake Washington within a month of emerging (captured by Martz, et al, 1996a and 1996b). Their migration to the lake would not be affected by the existing channel alternative. Other chinook fry likely rear in upstream areas, side channels, pools and/or tributaries. Transport of juvenile chinook through the project area prior to migrating out the ship canal would not be affected. Habitat for predators, such as rainbow and cutthroat trout will not increase, so chinook fry survival would not be affected by the existing channel alternative. 4.3.2.3 Minimal Dredge Alternative (Preferred Alternative) The minimal dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The lake backwater will extend from 3300 feet (1000 m) to the mouth. Access for adult chinook salmon may be enhanced slightly during low flows over the existing conditions. The levees and floodwalls will be protected as described in Section 2.2 with riprap below the OHWM. Spawning habitat for adult chinook would not likely be reduced because it is currently negligible. Only infrequent spawning occurs in the project area. Predator habitat may be increased by 253,000 feet2 (5.8 acres or 23,230 m2), as described in Section 4.3.1.3. The increase in predator habitat may reduce the survival of chinook fry and juveniles migrating through the lower Cedar River. 4.3.2.4 Moderate Dredge Alternative The moderate dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The lake -backwater will extend from 4200 feet (1300 m) to the mouth. Access for adult chinook salmon will be enhanced slightly during low flows over the existing conditions. The levees and floodwalls will be protected as described in Section 2.2 with riprap below the OHWM. Spawning habitat for adult chinook would not be reduced because it is currently negligible. Only infrequent spawning occurs in the project area: Predator habitat may be increased by 352,000 feet2 (8 acres or 32,320 m2) as described in Section 4.3.1.3. The increase in predator habitat will likely reduce the survival of chinook fry and juveniles migrating through the lower Cedar River. 4.3.2.5 Deep Dredge Alternative The deep dredge alternative will narrow the existing channel bottom (because of the v- shape) and will increase water depths over most of the project area. The lake backwater will extend from 5600 feet (1700 m) to the mouth. Access for adult chinook salmon will be enhanced slightly, during low flows, over the existing conditions. The levees and floodwalls will be protected as described in Section 2.2 with riprap below the OHWM. Spawning habitat for adult chinook would not be reduced because it is currently negligible. Only infrequent spawning occurs in the project area. Predator habitat may be increased by 506,000 feet2 (11.6 acres or 46,460 m2) as described in Section 4.3.1.3. The increase in predator habitat may significantly reduce the survival of Chinook fry and juveniles migrating through the lower Cedar River. 4.3.3 Coho Salmon 4.3.3.1 No Action Alternative The no action alternative will not immediately change the existing conditions for coho salmon. As the channel sediment aggrades, the reach below the south Boeing bridge would likely experience slightly increased water velocities as the channel bottom becomes higher above the lake level. Once the channel became nearly filled in and the river flow spreads out into the adjacent park and airport, the effects on coho salmon could be very negative. Adult coho would have a more difficult time ascending the lower portion of the river because depths would be dramatically reduced and the potential for stranding on the airport and other areas would be increased, especially because coho ascend the river in the fall and winter. Likewise, juvenile salmon would more easily be washed out onto the airport during high winter and spring flows experiencing stranding or contact with pollutants. The no action alternative is likely to have significant negative impacts on coho salmon in the future. 4.3.3.2 Existing Channel Alternative The existing channel alternative will modify the channel cross-section by removing existing gravel bars and deep holes. This will create a uniform depth across the channel which may reduce water depths. The reduced water depths will make it more difficult for adult coho salmon to ascend the lower Cedar River during low flows (-200 cfs). The existing depths at low flows already likely delay access by adult salmon. Spawning habitat for adult coho would not be changed from the existing condition. Only infrequent spawning occurs in the project area. Coho fry rear in upstream areas, side channels, pools and/or tributaries. Transport of juvenile coho through the project area prior to migrating out the ship canal would not be affected. 59 4.3.3.3 Minimal Dredge Alternative (Preferred Alternative) The minimal dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The lake backwater will extend from 3300 feet (1300 m) to the mouth. Access for adult coho salmon will be enhanced slightly during low flows over the existing conditions. The levees and floodwalls will be protected as described in Section 2.2 with riprap below the OHWM. Spawning habitat for adult coho would not be changed from the existing condition. Only infrequent spawning occurs in the project area. Predator habitat may be increased by 253,000 feet2 (23,230 m2) as described in Section 4.3.1.3. However, the increase in predator habitat will not likely reduce the survival of coho juveniles migrating through the lower Cedar River because they are much larger than other salmonid juveniles. Rearing habitat for coho may be increased because they often prey on sockeye fry and other small fish in the lower river (Tabor & Chan, 1996a and 1996b; Beauchamp, 1995). 4.3.3.4 Moderate Dredge Alternative The moderate dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The lake backwater will extend from 4200 feet (1300 m) to the mouth. Access for adult coho salmon will be enhanced slightly during low flows over the existing conditions. The levees and floodwalls will be protected as described in Section 2.2 with riprap below the OHWM. Spawning habitat for adult coho would not - be significantly changed from the existing condition. Only infrequent spawning occurs in the project area. Predator habitat may be increased by 352,000 feet2 (32,320 m2) as described in Section 4.3.1.3. The increase in predator habitat will not likely reduce the survival of coho juveniles migrating through the lower Cedar River and may increase rearing habitat for larger juveniles because there will be additional habitat to prey on sockeye fry and other small fish. 4.3.3.5 Deep Dredge Altemative The deep dredge alternative will narrow the existing channel bottom (because of the v- shape) and will increase water depths over most of the project area. The lake backwater will extend from 5600 feet (1700 m) to the mouth. Access for adult coho salmon will be generally unchanged, during low flows, over the existing conditions. The levees and floodwalls will be protected as described in Section 2.2 with riprap below the OHWM. Spawning habitat for adult coho may be reduced from the existing condition. It is not known to what extent spawning occurs in the area that would be affected by this alternative. Predator habitat may be increased by 506,000 feet2 (46,460 m2) as described in Section 4.3.1.3. The increase in predator habitat will not likely reduce the survival of coho juveniles migrating through the lower Cedar River and may increase rearing habitat for larger coho juveniles because of the additional opportunities to prey on sockeye fry and other small fish. M 4.3.4 Steelhead Trout For all dredging alternatives, during the actual construction and maintenance time periods, there is a slight chance that juvenile steelhead may be present in the river until early July. To minimize any impact to steelhead, the water will be diverted (in the reach above 3300 feet [1000 m] from the mouth) in a manner that will maintain a viable transportation corridor for steelhead during dredging. 4.3.4.1 No Action Alternative The no action alternative will not immediately change the existing conditions for steelhead trout. As the channel sediment aggrades, the reach below the south Boeing bridge would likely experience slightly increased water velocities as the channel bottom becomes higher above the lake level. Once the channel became nearly filled in and the river flow spreads out into the adjacent park and airport, the effects on steelhead trout could be very negative. Adult steelhead, returning in the winter, would have a more difficult time ascending the lower portion of the river because depths would be dramatically reduced and the potential for stranding on the airport and other areas would be increased. Likewise, juvenile steelhead would more easily be washed out onto the airport during high winter and spring flows experiencing stranding or contact with pollutants. The no action alternative is likely to have significant negative impacts on steelhead trout in the future. 4.3.4.2 Existing Channel Alternative The existing channel alternative will modify the channel cross-section by removing existing gravel bars and deep holes. This will create a uniform depth across the channel which may reduce water depths, during low flows. During high flow periods, when adult steelhead ascend the river, the loss of scour pool habitat may make it more difficult for steelhead to ascend against high currents. Spawning habitat for adult steelhead would not be changed from the existing condition. No known spawning occurs in the project area. Steelhead juveniles rear in upstream areas, side channels, pools and/or tributaries. Steelhead smolts may feed in the lower Cedar River on their way out to the locks. Transport of steelhead smolts through the project area prior to migrating out the ship canal would not be affected after project construction. 4.3.4.3 Minimal Dredge Alternative (Preferred Alternative) The minimal dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The lake backwater will extend from 3300 feet (1300 m) to the mouth. The levees and floodwalls will be protected as described in Section 2.2 with riprap below the OHWM. Spawning habitat for adult steelhead would not be changed from the existing condition. No known spawning occurs in the project area. Backwater habitat will be increased by 253,000 feet' (23,230 m2) as described in Section 4.3.1.3. A This may increase foraging habitat for steelhead smolts during their transit through this reach. 4.3.4.4 Moderate Dredge Alternative The moderate dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The lake backwater will extend from 4200 feet (1300 m) to the mouth. The levees and floodwalls will be protected as described in Section 2.2 with riprap below the OHWM. Spawning habitat for adult steelhead would not be changed from the existing condition. No known spawning occurs in the project area. Backwater habitat will be increased by 352,000 feet2 (32,320 m') as described in Section 4.3.1.3. This may increase foraging habitat for steelhead smolts during their transit through this reach. 4.3.4.5 Deep Dredge Alternative The deep dredge alternative will narrow the existing channel bottom (because of the v- shape) and will increase water depths and decrease velocities over most of the project area. The lake backwater will extend from 5600 feet (1500 m) to the mouth. Access for adult steelhead salmon will be generally unchanged from the existing conditions. The levees and floodwalls will be protected as described in Section 2.2 with riprap below the OHWM. Spawning habitat for adult steelhead would not be changed from the existing condition. No known spawning occurs in the project area. Backwater habitat will be increased by 506,000 feet' (46,460 m') as described in Section 4.3.1.3. This may increase foraging habitat for steelhead smolts during their transit through this reach. 4.3.5 Sea -Run Cutthroat Trout It is unknown if sea -run cutthroat trout are present in the Cedar River. If they do exist in the river, their habitat needs and run timing is similar to steelhead trout. Impacts would be nearly identical to those identified in Section 4.3.4 for steelhead. 4.3.6 Resident Cutthroat and Rainbow Trout 4.3.6.1 No Action Alternative The no action alternative will not change the existing habitat for resident cutthroat or rainbow trout in the short term. As the sediment continues to aggrade, the channel bottom will get closer to the airport level and resident trout may be washed onto the airport or park in moderate -high flows. Likewise, juvenile trout would more easily be washed out onto the airport during high winter and spring flows experiencing stranding or contact with pollutants. The trout could move upstream farther to find suitable habitat, but it is likely that upstream habitats are already occupied by resident cutthroat or rainbow trout. Trout may also be displaced into Lake Washington. The no action 62 alternative is likely to have negative impacts on resident cutthroat or rainbow trout in the project area. 4.3.6.2 Existing Channel Alternative The existing channel alternative will modify the channel cross-section by removing existing gravel bars and deep holes. This will create a uniform depth across the channel which may reduce water depths, during low flows and will also eliminate bank scour holes which resident trout prefer. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which will replace the habitat lost from dredging. It is likely that overall, resident trout will not be significantly affected by the existing channel alternative. 4.3.6.3 Minimal Dredge Alternative (Preferred Alternative) The minimal dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The v-shape will tend to eliminate bank scour holes which resident trout prefer. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which will replace the habitat lost from dredging. The lake backwater will extend up to 3300 feet (1300 m), an increase of 253,000 feet2 (23,230 m2). This may increase foraging habitat for cutthroat trout in the lake -like area (feed on sculpins, fish eggs, etc.), but both rainbow and cutthroat appear to prefer to reside in pools further upstream. It is likely that overall, resident trout will not be significantly affected by the minimal dredge alternative. 4.3.6.4 Moderate Dredge Alternative The moderate dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The v-shape will tend to eliminate bank scour holes which resident trout prefer. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which will replace the habitat lost from dredging. The lake backwater will extend up to 4200 feet (1300 m), an increase of 352,000 feet2 (32,320 m2). This may increase foraging habitat for cutthroat trout in the lake -like area (feed on sculpins, fish eggs, etc.). Overall, habitat may be increased for resident trout in the project area. 4.3.6.5 Deep Dredge Alternative The deep dredge alternative will narrow the existing channel bottom (because of the v- shape) and will increase water depths. The v-shape will tend to eliminate bank scour holes which resident trout prefer. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which will replace the habitat lost from dredging. The lake backwater will extend up to 5600 feet (1700 m), an increase of 506,000 feet2 (46,460 m2). This will nearly replace the existing bank scour pool habitat 63 with lake backwater. It is likely that cutthroat trout will utilize the lake backwater habitat for foraging, but both trout species may use smaller pools further upstream for resting and hiding. The placement of armoring to protect levees and floodwalls may create nooks which will replace the habitat lost from dredging. Overall, habitat (especially foraging habitat) will be increased for resident trout in the project area. 4.3.7 Longfin Smelt 4.3.7.1 No Action Alternative The no action alternative will not have significant impacts on longfin smelt in the short term. Longfin smelt only use the Cedar River for spawning and egg development. As sediment continues to aggrade, the bottom sediments will likely become dominated by gravel and cobbles and less sandy in the lower reach, which may be less preferred by smelt for spawning. Velocities will likely increase until the flows spread onto the airport and this will reduce the distance upstream that smelt are able to reach from Lake Washington. As flows spread out onto the airport and park, smelt may experience stranding and come into contact with pollutants, or they may not be able to enter the river at all. The no action alternative is likely to have significant negative impacts on longfin smelt spawning in the future. 4.3.7.2 Existing Channel Alternative The existing channel alternative will modify the channel cross-section by removing existing gravel bars and deep holes. This will create a uniform depth across the channel which may reduce water depths, during low flows and will also eliminate bank scour holes which smelt rest and/or spawn in. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which will partially replace the habitat lost from dredging. Overall, it is not likely that the existing channel alternative will significantly affect longfin smelt. 4.3.7.3 Minimal Dredge Alternative (Preferred Alternative) The minimal dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The v-shape will tend to eliminate bank scour holes which smelt rest and/or spawn in. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which will partially replace the habitat lost from dredging. The lake backwater will extend up to 3300 feet (1300 m), an increase of 253,000 feet2 (23,230 m2). This will increase the preferred lower velocity, finer substrate habitat and will likely positively benefit longfin smelt. Overall, it appears that longfin smelt spawning may be slightly enhanced by the minimal dredge alternative. 4.3.7.4 Moderate Dredge Alternative The moderate dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The v-shape will tend to eliminate bank scour holes which smelt rest and/or spawn in. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which may partially replace the habitat lost from dredging. The lake backwater will extend up to 4200 feet (1300 m), an increase of 352,000 feet' (32,320 m2). This will increase preferred lower velocity, finer substrate area and will likely positively benefit longfin smelt. Overall, it appears that longfin smelt spawning may be enhanced by the moderate dredge alternative. 4.3.7.5 Deep Dredge Alternative The deep dredge alternative will narrow the existing channel bottom (because of the v- shape) and will increase water depths. The v-shape will tend to eliminate bank scour holes which rest and/or spawn in. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which may partially replace the habitat lost from dredging. The lake backwater will extend up to 5600 feet (1700 m), an increase of 506,000 feet2 (46,460 m2). This will nearly replace the existing bank scour pool habitat with lake backwater. This will dramatically increase preferred lower velocity, finer substrate area and will positively benefit longfin smelt. Overall, it appears that longfin smelt spawning may be significantly enhanced by the deep dredge alternative. 4.3.8 Sculpins 4.3.8.1 No Action Alternative The no action alternative will not likely affect sculpins or their habitat during the short term. As sediment continues to aggrade, it is likely that habitat for coastrange, torrent and reticulate sculpin will increase as the lower river builds up larger sediment with higher velocities. Prickly sculpin habitat will concomitantly decrease. As the river flows spread out onto the airport and park areas, sculpins may be stranded or come into contact with pollutants. Overall, prickly sculpin habitat will likely be reduced and habitat for the other species will likely increase, but winter flows will likely displace sculpins from the river each year. 4.3.8.2 Existing Channel Alternative The existing channel alternative will modify the channel cross-section by removing existing gravel bars and deep holes. This will create a uniform depth across the channel which may reduce water depths, during low flows and will also eliminate bank scour holes which prickly and reticulate sculpin prefer. The placement of armoring to protect the floodwall may create nooks with quieter water which will partially replace the habitat lost from dredging. The actual construction and maintenance dredging will 65 affect sculpins because they are resident in the river during the construction window. Sculpin will be displaced upstream or into the lake and there will likely be some mortality associated with dredging. The frequency of dredging (maximum of every 3 years) will provide a periodic disturbance to sculpins and their habitat, although recolonization will rapidly occur after each dredge cycle. Overall, sculpin habitat is not likely to be significantly changed. 4.3.8.3 Minimal Dredge Alternative (Preferred Alternative) The minimal dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The v-shape will tend to eliminate bank scour holes which prickly and reticulate sculpin prefer. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which will replace the habitat lost from dredging. The lake backwater will extend up to 3300 feet (1300 m), an increase of 253,000 feet2 (23,230 m2). This will increase habitat preferred by prickly sculpin and reduce habitat preferred by coastrange and torrent sculpin. The actual construction and maintenance dredging will affect sculpins because they are resident in the river during the construction window. Sculpin will be displaced upstream or into the lake and there will likely be extensive mortality associated with dredging. The frequency of dredging (maximum of every 3 years) will provide a periodic disturbance to sculpins and their habitat, although recolonization will likely occur within one year following each dredge cycle. Overall, while habitat for prickly sculpin will be increased, populations of sculpin will likely only slightly increase as a result of periodic maintenance dredging. 4.3.8.4 Moderate Dredge Alternative The moderate dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The v-shape will tend to eliminate bank scour holes which prickly and reticulate sculpin prefer. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which will replace the habitat lost from dredging. The lake backwater will extend up to 4200 feet (1300 m), an increase of 352,000 feet2 (32,320 mz). This will increase habitat preferred by prickly sculpin and reduce habitat preferred by coastrange and torrent sculpin. The actual construction and maintenance dredging will affect sculpins because they are resident in the river during the construction window. Sculpin will be displaced upstream or into the lake and there will likely be extensive mortality associated with dredging. The frequency of dredging (maximum of every 3 years) will provide a periodic disturbance to sculpins and their habitat, although recolonization will likely occur within one year following each dredge cycle. Overall, while habitat for prickly sculpin will be significantly increased, populations of sculpin will likely only moderately increase over time as a result of periodic maintenance dredging. 4.3.8.5 Deep Dredge Alternative The deep dredge alternative will narrow the existing channel bottom (because of the v- shape) and will increase water depths. The v-shape will tend to eliminate bank scour holes which rest and/or spawn in. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which will replace the habitat lost from dredging. The lake backwater will extend up to 5600 feet (1700 m), an increase of 506,000 feet' (46,460 m') This will replace most of the existing higher velocity riffle and bank scour pool habitat with lake backwater. This will nearly eliminate habitat for coastrange, torrent and reticulate sculpin, in the project area, and replace it with habitat for prickly sculpin. The actual construction and maintenance dredging will affect sculpins because they are resident in the river during the construction window. Sculpin will be displaced upstream or into the lake and there will likely be some mortality associated with dredging. Overall, the deep dredge alternative will likely eliminate most of the habitat for Coastrange, torrent and reticulate sculpins in the project area. Habitat for prickly sculpin will be dramatically increased, and the population will likely significantly increase even with periodic dredging impacts. 4.3.9 Other Native Fish Species The other native species discussed in this section are: mountain whitefish, northern squawfish, largescale sucker, peamouth chub, and three -spine stickleback. Brook lamprey larvae have been collected during sediment sampling in the lower Cedar River, however no other information is known about brook lamprey use of the area. Longnose dace has not been observed in the project area, although they prefer riffle habitat, such as is found above 4000 feet (1200 m) upstream of the mouth. Northern squawfish, peamouth chub and three -spine stickleback are only occasionally found in the lower Cedar River, probably only straying from their primary habitat in the lake. 4.3.9.1 No Action Alternative The no action alternative will not likely affect any of the above species or their habitat during the short term. Mountain whitefish and largescale suckers are the only species found year-round in the lower Cedar River. Northern squawfish, peamouth chub and three -spine stickleback are found only from late spring through early fall, when the water temperatures are fairly high. As the sediment continues to aggrade, velocities will increase near the mouth of the river, and squawfish, peamouth and stickleback would likely be displaced back into the lake (they prefer quiet waters). Whitefish and suckers would likely remain in bank scour holes, but could be washed onto the airport or park during high flows. They would likely experience stranding or come into contact with pollutants. Overall, the no action alternative is likely to have negative impacts on these other native species in the future. 67 4.3.9.2 Existing Channel Alternative The existing channel alternative will modify the channel cross-section by removing existing gravel bars and deep holes. This will create a uniform depth across the channel which may reduce water depths, during low flows and will also eliminate bank scour holes which whitefish and suckers prefer. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which will replace the habitat lost from dredging. The actual construction and maintenance dredging will affect whitefish and suckers because they are resident in the river during the construction window. Also, squawfish may spawn during the early portion of the construction window. All of these species would likely be displaced into the lake during construction. Overall, the existing channel alternative would not significantly impact any of the above native species. Brook lamprey larvae will be killed or displaced during construction and maintenance dredging. Overall, their populations may decline as a result of the existing channel alternative. 4.3.9.3 Minimal Dredge Alternative (Preferred Alternative) The minimal dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The v-shape will tend to eliminate bank scour holes which whitefish and suckers prefer. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which will replace the habitat lost from dredging. The lake backwater will extend up to 3300 feet (1000 m), an increase of 253,000 feet2 (23,230 m2). This increase in lake -like habitat will likely increase habitat available for northern squawfish, peamouth, largescale suckers and three -spine stickleback. The actual construction and maintenance dredging will affect whitefish and suckers because they are resident in the river during the construction window. Also, squawfish may spawn during the early portion of the construction window. All of these species would likely be displaced into the lake during construction. Overall, the minimal dredge alternative may enhance habitat for the most of the above native species. Brook lamprey larvae will be killed or displaced during construction and maintenance dredging. Overall, their populations will likely decline as a result of the minimal dredge alternative. 4.3.9.4 Moderate Dredge Alternative The moderate dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The v-shape will tend to eliminate bank scour holes which whitefish and suckers prefer. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which will replace the habitat lost from dredging. The lake backwater will extend up to 4200 feet (1300 m), an increase of 352,000 feet2 (32,320 m2). This increase in lake -like habitat will likely increase habitat available for northern squawfish, peamouth, largescale suckers and three -spine stickleback. The actual construction and maintenance dredging will affect whitefish and suckers because they are resident in the river during the construction window. Also, squawfish may spawn during the early portion of the construction window. All of these species would likely be displaced into the lake during construction. Overall, the moderate dredge alternative will likely enhance habitat for the most of the above native species. Brook lamprey larvae will be killed or displaced during construction and maintenance dredging. Overall, their populations will likely decline as a result of the moderate dredge alternative. 4.3.9.5 Deep Dredge Alternative The deep dredge alternative will narrow the existing channel bottom (because of the v- shape) and will increase water depths. The v-shape will tend to eliminate bank scour holes which whitefish and suckers prefer. The placement of armoring to protect levees and floodwalls may create nooks with quieter water which will replace the habitat lost from dredging. The lake backwater will extend up to 5600 feet (1700 m), an increase of 506,000 feet' (46,460 m'). This will nearly replace the existing higher velocity riffle and bank scour pool habitat with lake backwater. This will dramatically increase the habitat utilized by squawfish, peamouth, suckers and three -spine stickleback. Mountain whitefish will also likely utilize the lake -like environment or move upstream. The actual construction and maintenance dredging will affect whitefish and suckers because they are resident in the river during the construction window. Also, squawfish may spawn during the early portion of the construction window. All of these species would likely be displaced into the lake during construction. Overall, the deep dredge alternative may greatly enhance habitat for the most of the above native species. Brook lamprey larvae will be killed or displaced during construction and maintenance dredging. Overall, their populations will likely decline as a result of the deep dredge alternative. 4.3.10 Non -Native Fish Species Non-native fish species found in the project area include yellow perch, smallmouth bass, pumpkinseed sunfish and brown bullhead. These species are only occasionally present during late spring and summer, when the water temperatures are high and are typically found only in the lowest portion of the river which is lake -like. Their primary habitat is in Lake Washington. 4.3.10.1 No Action Alternative The no action alternative will have no effect on non-native species in the short term. As sediment continues to aggrade, it is likely the lowest portion of the river, which they currently utilize will become too fast -flowing and these species will be displaced into Lake Washington. Overall, the no action alternative will slightly decrease the amount of habitat available for these non-native species. 4.3.10.2 Existing Channel Alternative The existing channel alternative will modify the channel cross-section by removing existing gravel bars and deep holes. This will create a uniform depth across the channel which may reduce water depths upstream of the lake -like area, during low flows and will also eliminate bank scour holes. However, these species typically only utilize the lake -like lower river which will remain essentially the same after project construction. The actual construction and maintenance dredging will likely displace non-native species into the lake because that is the time of year they are present in the river. Overall, the existing channel alternative will have negligible effect on non-native species. 4.3.10.3 Minimal Dredge Alternative (Preferred Alternative) The minimal dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The lake backwater will extend from 3300 feet (1000 m) to the mouth, an increase of 253,000 feet2 (23,230 m2). This will increase habitat utilized by non-native species. The actual construction and maintenance dredging will likely displace non-native species into the lake because that is the time of year they are present in the river. Overall, the minimal dredge alternative may slightly enhance habitat for non-native species. 4.3.10.4 Moderate Dredge Alternative The moderate dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The lake backwater will extend from 4200 feet (1300 m) to the mouth, an increase of 352,000 feet2 (32,320 m'). This will increase habitat utilized by non-native species. The actual construction and maintenance dredging will likely displace non-native species into the lake because that is the time of year they are present in the river. Overall, the moderate dredge alternative may slightly enhance habitat for non-native species. 4.3.10.5 Deep Dredge Alternative The deep dredge alternative will narrow the existing channel bottom (because of the v- shape) and will increase water depths. The lake backwater will extend up to 5600 feet (1700 m), an increase of 506,000 feet' (46,460 m'). This will nearly replace the existing higher velocity riffle and bank scour pool habitat with lake backwater. This will dramatically increase the habitat utilized by non-native species. The actual construction and maintenance dredging will likely displace non-native species into the lake because that is the time of year they are present in the river. Overall, the deep dredge alternative will increase habitat for non-native species. 70 4.4 Aquatic Invertebrates 4.4.1 No Action Alternative The no action alternative will not have any effect on aquatic invertebrates in the short term. The existing invertebrates will continue to have sediments deposited on top of them during moderate -high flows and will recolonize each spring. As sediment continues to aggrade, it is likely that habitat for organisms which prefer higher velocity gravel riffles will increase as the lake -like habitat is reduced. This would likely mean an increase in populations of Plecopterans and Ephemeropterans which are preferred prey items for juvenile salmonids. Overall, the no action alternative will not likely affect overall abundance of invertebrates, but may replace slow velocity species with high velocity species. However, the likely increased input of pollutants as the river flows onto the airport and Boeing may decrease invertebrate populations. 4.4.2 Existing Channel Alternative The existing channel alternative will modify the channel cross-section by removing existing gravel bars and deep holes. This will create a uniform depth across the channel which may reduce water depths upstream of the lake -like area, during low flows and will also eliminate bank scour holes. This will tend to make all of the project area above 1000 feet (300 m) a higher velocity riffle area. This will provide a slightly increased amount of habitat for Plecopterans and Ephemeropterans. However, the abundance and diversity of aquatic invertebrates is not expected to change significantly. The existing invertebrates will continue to have sediments deposited on top of them during moderate -high flows and will recolonize each spring. However, because construction and maintenance dredging will occur periodically during the season of maximal invertebrate growth and abundance, populations of invertebrates may decline over time. Overall, the existing channel alternative may cause a slight decline of invertebrate populations in the future due to frequent maintenance dredging. 4.4.3 Minimal Dredge Alternative (Preferred Alternative) The minimal dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The lake backwater will extend from 3300 feet (1000 m) to the mouth, an increase of 253,000 feet2 (23,230 m2). Upstream of 3300 feet (1000 m), higher velocity habitat for Plecopterans and Ephemeropterans may be slightly increased. From 3300 feet (1000 m) to the mouth, organisms which prefer low velocities and finer substrates will have increased habitat. Such organisms include Megalopterans, Dipterans, Trichopterans and some species of Chironomidae. The existing invertebrates will continue to have sediments deposited on top of them during moderate -high flows and will recolonize each spring. However, because construction and maintenance dredging will occur periodically during the season of maximal invertebrate growth and abundance, populations of invertebrates may decline over time. Overall, the minimal dredge alternative may cause a decline of invertebrate 71 populations in the future, and will reduce invertebrate species that are preferred prey items for juvenile salmonids. 4.4.4 Moderate Dredge Alternative The moderate dredge alternative will narrow the existing channel bottom (because of the v-shape) and will likely increase water depths and velocities slightly, upstream of the south Boeing bridge. The lake backwater will extend from 4200 feet (1300 m) to the mouth, an increase of 352,000 feet2 (32,320 m2). Upstream of 4200 feet (1300 m), higher velocity habitat for Plecopterans and Ephemeropterans may be slightly increased. From 4200 feet (1300 m) to the mouth, organisms which prefer low velocities and finer substrates will have increased habitat. Such organisms include Megalopterans, Dipterans, Trichopterans and some species of Chironomidae. The existing invertebrates will continue to have sediments deposited on top of them during moderate -high flows and will recolonize each spring. However, because construction and maintenance dredging will occur periodically during the season of maximal invertebrate growth and abundance, populations of invertebrates may decline over time. Overall, the moderate dredge alternative may cause a decline of invertebrate populations in the future, and will reduce invertebrate species that are preferred prey items for juvenile salmonids. 4.4.5 Deep Dredge Alternative The deep dredge alternative will narrow the existing channel bottom (because of the v- shape) and will increase water depths. The lake backwater will extend up to 5600 feet (1700 m), an increase of 506,000 feet2 (46,460 m2). This will nearly replace the existing higher velocity riffle and bank scour pool habitat with lake backwater. Most of the existing habitat for organisms which prefer higher velocities and gravel substrate will be replaced with lake backwater and fine substrates. This may dramatically reduce the overall abundance and diversity of aquatic invertebrates in the project area. The existing invertebrates will continue to have sediments deposited on top of them during moderate -high flows and will recolonize each spring. However, because construction and maintenance dredging will occur periodically during the season of maximal invertebrate growth and abundance, populations of invertebrates may decline over time. Overall, it is likely that the deep dredge alternative would have significant impacts on invertebrate diversity and population abundance in the future, and would significantly reduce invertebrate species that are preferred prey items for juvenile salmonids. 4.5 Wildlife 4.5.1 No Action Alternative The no action alternative will not change the existing riverine and adjacent park habitat in the short term 'and will have no effect on mammal or bird species. As sediment continues to aggrade, bird species such as gulls which rest on gravel bars will have 72 increased habitat. If fish populations are reduced from continued sediment deposition, birds which prey on fish may move to other locations. Overall, the no action alternative is not likely to significantly affect bird and wildlife species. 4.5.2 All Dredging Alternatives All of the dredging alternatives will require the construction of levees and/or floodwalls along both banks of the river. This will cause the removal of all existing vegetation on the left bank (which consists of approximately 5 large cottonwood trees and a few scattered willows and alders) and some vegetation on the right bank (likely fewer than 10 trees or shrubs). Revegetation will occur, but on the left bank, large cottonwood trees will be replaced with smaller shrubby willows or other smaller trees. This will cause an impact for 3-5 years on wildlife species that primarily utilize the existing amount of mature wooded habitat. After that time, the vegetation will likely grow to a sufficient height and density to replace or even improve the existing habitat. During construction, the noise and equipment will likely cause most mammal and bird species to move from the area, at least during working hours. The dredging activities will not likely affect most mammal species. However, bird species which utilize gravel bars (gulls, geese) in the river currently for resting or feeding will be displaced. Some of these birds could utilize the delta area, but others will likely move onto the airport or park areas for better habitat. Revegetation of the right bank with more tree and shrub species will tend to reduce the use of the park area by gulls, coots and Canada geese. However, several other bird species will benefit from the increase in riparian vegetation including green -winged teal, hooded mergansers, hairy woodpecker, violet -green swallow, American crow, common bushtit, etc. (see Table in Section 3.6). The City of Renton considers the presence of large numbers of gulls to be a safety hazard at the airport and a reduction of gravel bar/resting habitat may reduce their numbers. However, as was observed (Harza, 1995) after dredging the delta in 1993, birds which formerly utilized the delta gravel bar and woody debris moved onto the airport or park following the removal of the gravel bar. This project is expected to reduce gull and geese populations in the area by removing both gravel bars and riparian grassed areas which are prime habitat for these birds. The removal of gravel bars and riparian grassed areas will reduce habitat for these birds by approximately 50%. Overall, mammal habitat will likely be reduced in the short term following construction, but after 5 years when the vegetation regrows the habitat may be improved for mammals. Gravel bar habitat will- be eliminated in the lower river for birds (mainly gulls). Smaller species which utilize riparian habitat will have more nesting and hiding habitat after 5 years. 73 4.6 Threatened and Endangered Species 4.6.1 Bald Eagle 4.6.1.1 No Action Alternative The no action alternative will not affect bald eagles in the short term. If fish populations are reduced as the sediment continues to aggrade, then foraging would be reduced for bald eagles. Other elements of habitat, such as perching areas will remain similar to the existing condition. Overall, the no action alternative may have slight negative effects on bald eagles if their prey base is reduced. 4.6.1.2 All Dredging Alternatives During construction and maintenance, the noise and equipment will likely disturb any bald eagles perching in the area. However, there are no known nests within 3 miles (4.8 km), so nesting activities would not likely be disrupted. After construction, there will be no -gravel bar habitat, except on the delta. The delta (and its woody debris) is currently the only site within the project area that is frequently utilized by bald eagles. The delta and its woody debris would not be removed for any dredging alternatives. Increased riparian vegetation, after 3-5 years will likely improve eagle perching habitat. Overall, the dredging alternatives are not likely to have a significant impact on bald eagles. 4.6.2 Candidate Salmon Species The impacts likely to candidate salmon species are described in Sections 4.3.2-4.3.5. 4.6.3 Species of Concern: Northwestern Pond Turtles Northwestern pond turtles have not been observed, to date, in the project area. The only likely suitable habitat in the project area would be the delta and its associated woody debris. The action alternatives will not affect the delta (or debris) and will not likely adversely affect northwestern pond turtles. 4.7 Vegetation 4.7.1 No Action Alternative The no action alternative will have no effect on terrestrial vegetation in the project area. The parks department will continue to maintain the riparian zone similar to the existing condition. As the sediment continues to aggrade, sediment will likely build up in the riparian zone, burying small shrubs. Non-native species will likely continue to dominate much of the riparian zone. Aquatic vegetation in the lower river may be reduced as sediment accumulates and creates a higher velocity, coarser substrate environment. 74 4.7.2 All Dredging Alternatives All dredging alternatives will require the removal of riparian vegetation along the left bank to accommodate construction of levees and/or floodwalls (approximately 5 large cottonwoods and a few scattered willows and alders). The levees along the right bank will be set back from the river's edge but may require minimal removal of vegetation during construction. The riparian zone will be revegetated to the maximum extent possible with willows, and other native species such as Oregon ash, mock orange, Indian plum, and Oregon grape. It is expected that within 3-5 years after construction the riparian zone will be more extensive than presently exists. Non-native species will be replaced with native species. Overall, for 3-5 years after construction vegetation will be slightly reduced, but after that time period, vegetation diversity and abundance be increased. Aquatic vegetation in the lower river will be removed during construction and maintenance activities. However, this area of the river is currently covered with sediment each winter and it is likely that aquatic vegetation will recolonize backwater areas. Aquatic vegetation will be increased for the minimal, moderate and deep dredge alternatives over the existing condition. It is a concern that Eurasian watermilfoil could become established in any increased lake backwater habitat; it is a widespread problem in Lake Washington. Currently, the lower river does not have any Eurasian watermilfoil, perhaps due to the sediment load coming down the river. This sediment will continue to accumulate between maintenance dredging cycles and may prevent watermilfoil introduction. 4.8 Cultural Resources There are no known cultural or historic resources sites in the project area. The State Historic Preservation Office has been coordinated with and concurs with the Corps assessment of existing conditions. During construction of any of the dredging alternatives, a Corps' archaeologist would be available should any artifacts be discovered. There are no expected impacts on cultural or historic resources from any of the alternatives. 4.9 Land Use/Recreation/Public Use 4.9.1 No Action Alternative The no action alternative will continue and increase the existing damages and/or closures that occur during high water. Future average annual damages are estimated to be $14 million. Recreation and public use of the Cedar River Trail is restricted during much of the winter (flows >1500 cfs). This situation would continue to worsen under the no action alternative. Flooding impacts to adjacent properties, airport and Boeing would also continue to worsen, and sediment would continue to accumulate upstream of Logan Avenue and would cause increased flooding in other areas of Renton. Overall, the no action alternative would have significant negative flooding impacts on 75 land use, recreation and public use of the project area and is the reason why a flood control project has been proposed. 4.9.2 All Dredging Alternatives All dredging alternatives will contain flooding up to the 100 year flood in Renton. The construction of levees and floodwalls will reduce public viewing of the river from the left bank, although public access is minimal from this side currently. The right bank levees will require the modification of existing park facilities including the trail, boat ramp, basketball court and some picnic facilities. The trail will be relocated, likely on top of the levee, which will increase views of the river and lake. The boat ramp will be retained, but will likely allow access by hand carried vessels only (i.e. canoes, kayaks). The basketball court and picnic facilities will be relocated within the park. During construction, the park will likely be closed for the duration. Dredge material from the lower river will likely be dewatered near the boat ramp and then will be hauled by truck to the upland disposal site. Levee construction will relocate many park features as described above. During maintenance dredging, Renton will seek to avoid all impacts on the park by placing dredged material on barges or using the airport road at night for truck hauling of dredged material. 4.10 Transportation 4.10.1 No Action Alternative The no action alternative would have impacts to transportation elements during flooding season. Logan Avenue bridge was closed during the 1995-1996 flooding because of instability. The Boeing bridges were also closed due to excessive debris buildup and high water. These impacts would occur more frequently, and to more bridges upstream, in the future as the channel bed continues to accumulate sediment. It is likely that the south Boeing bridge could sustain severe damages or fail altogether in a large flood event. The airport is also closed during flooding due to water on or near the runway and the deposition of debris. If no action were taken, the river would eventually avulse onto the airport and would likely close most uses of the airport, except during the low water summer season. 4.10.2 All Dredging Alternatives During construction there will be significant impacts on local transportation. Heavy equipment and trucks will be present on both sides of the channel. Airport operations may need to be scheduled during specific time periods of the day to accommodate dredging at the mouth and placement of low levees along the left bank. If this is required, the aviation public will be notified prior to construction. The proposed haul route for dredged material is shown in Figure 15. The proposed haul route seeks to minimize traffic problems by avoiding roads with heavy traffic such as Rainier Avenue 76 that currently have significant rush-hour difficulties. However, it is expected that there will be some road damage from the heavy truck traffic. The mitigation proposed in Section 5 includes planting the riparian zone on the right bank from the south Boeing bridge to the mouth. Also willows would be planted on the left bank. These plantings will eliminate several areas of grassed riparian zone which currently exist. It is expected that the removal of grassy areas and gravel bars in the channel will reduce habitat for potentially hazardous birds (gulls, geese) by approximately 50%. This is expected to have a beneficial effect on aircraft safety by reducing the populations of these potentially hazardous birds in the area. 4.10.2.1 Existing Channel Alternative Approximately 31,000 CY of material will be removed with the existing channel alternative. All of this material will be downstream of Logan Avenue. This volume of material will require 1,550 truck loads of material to be hauled up to the disposal site. This dredging could likely be accomplished in 30 days, with approximately 4 truck -loads per hour traveling to the disposal site and back. 4.10.2.2 Minimal Dredge Alternative (Preferred Alternative) Approximately 158,000 CY of material will be removed with the minimal dredge alternative. Most of this material will be removed downstream of Logan Avenue, with some material removed between Logan Avenue and Williams Avenue. This volume of material will require 7,900 truck loads of material to be hauled up to the disposal site. This dredging could likely be accomplished in 75 days, with approximately 9 truck -loads per hour traveling to the disposal site and back. 4.10.2.3 Moderate Dredge Alternative Approximately 195,000 CY of material will be removed with the moderate dredge alternative. Most of this material will be removed downstream of Logan Avenue, with some material removed between Logan Avenue and Wells Avenue. This volume of material will require 9,750 truck loads of material to be hauled up to the disposal site. This dredging could likely be accomplished in 60 - 75 days, with approximately 11 truck -loads per hour traveling to the disposal site and back. 4.10.2.4 Deep Dredge Alternative Approximately 260,000 CY of material will be removed with the moderate dredge alternative. Most of this material will be removed downstream of Logan Avenue, with some material removed between Logan Avenue and Wells Avenue. This volume of material will require 13,000 truck loads of material to be hauled up to the disposal site. This dredging could likely be accomplished in 75 - 90 days, with approximately 12 truck -loads per hour traveling to the disposal site and back. 77 4.11 Air/Noise/Light 4.11.1 No Action Alternative The no action alternative will not change the existing air quality, noise and lighting characteristics of the area. 4.11.2 All Dredging Alternatives All dredging alternatives will slightly increase air pollutants, noise and light in the area during initial construction and future maintenance activities. The Puget Sound Air Pollution Control Agency (J. Pade, pers. comm.) does not consider air quality impacts from construction equipment and trucks to significantly increase pollutants over the existing condition. Noise from the airport and Boeing currently is high, so construction should not significantly increase noise in the area. Lights will only be used if dredging operations occur at night. However, there are currently many lights surrounding Boeing and the airport, and construction operations should not significantly affect the existing condition. 4.12 Aesthetics 4.12.1 No Action Alternative The no action alternative will not change aesthetic conditions in the area. During flood events, sediments will continue to accumulate in many areas of the park and airport, which could be considered unattractive. As the channel fills in, the park would be inundated considerably more frequently. 4.12.2 All Dredging Alternatives All dredging alternatives will require the placement of floodwalls and levees along both banks. Levee/floodwall height will range from 1-8 feet (0.3-2.4 m). Views of the river will be restricted on the left bank (airport side) due to the floodwalls. However, there will be room in most locations, along the left bank, to plant willows or other riparian species on the river side of the floodwalls/levees. Riparian vegetation planted along the right bank will enhance the "natural' aesthetic of the river corridor and provide shading during warm summer months. The highly maintained appearance of the existing park will be reduced due to riparian plantings and construction of levees. Relocation of the trail on top of, or adjacent to, the levee will allow enhanced viewing of the river and Lake Washington. 4.13 Public Services/Utilities/Energy 4.13.1 No Action Alternative Public and private utilities would likely be disrupted in the future by the no action alternative. Existing power and water lines could be flooded or damaged by debris during flooding events. The south Boeing bridge has several utility lines running across it, which have already been subject to damage from debris. 4.13.2 All Dredging Alternatives Any public or private utilities that may be affected by this proposed project will be relocated underground behind the levees/floodwalls during initial construction. Utilities that are currently underground will either be relocated behind the levees/floodwalls or protected from erosion. 4.14 Public Health and Safety 4.14.1 No Action Alternative Public health and safety will continue to be threatened during flooding events with the no action alternative. This will occur more frequently as the channel bottom continues to accumulate sediment. 4.14.2 All Dredging Alternatives All dredging alternatives will alleviate public health and safety concerns from flooding and sediment accumulation in the project vicinity. 4.15 Likely Irretrievable Commitment of Resources 4.15.1 No Action Alternative The no action alternative will have no irretrievable commitment of resources. The no action alternative will continue to cause damage to resources which have already been committed, such as municipal and industrial facilities. 4.15.2 All Dredging Alternatives Construction and maintenance of this project will require significant uses of non- renewable energy sources, such as gasoline/diesel to fuel the heavy equipment and trucks. However, in light of the significant flooding problem, this appears to be a minor commitment of resources to solve the flooding problem. 79 4.16 Aquatic Ecosystem Interactions 4.16.1 No Action Alternative As described in Sections 4.3 and 4.4, salmon populations may be reduced as a result of the no action alternative due to reduced access and more frequent flooding and scouring of the river channel. Smelt populations will also likely be reduced due to reduced access. This may have a negative effect on the Lake Washington aquatic ecosystem because small pelagic fish populations will be reduced, thus reducing prey resources for larger fish such as cutthroat and rainbow trout, and squawfish. Aquatic invertebrate populations would likely increase as a result of this scenario and may affect water clarity and other factors. 4.16.2 Dredging Alternatives As described in Sections 4.3 and 4.4, sockeye and chinook fry survival will likely be reduced due to increased predator populations. Invertebrate diversity and abundance will also be reduced with species that prefer slower water velocites predominating. Longfin smelt populations are not likely to be adversely affected. Any reduction of sockeye fry populations may benefit smelt populations because of reduced competition for the same zooplankton resources in the lake. However, the increased predator population may focus more effort on longfin smelt. It is not known to what extent the sockeye and longfin smelt interactions may affect their population size. The preferred alternative would likely maintain the existing interactions (especially with mitigation). This should reduce the likelihood of unforeseen negative impacts occurring to the aquatic ecosystem. It is not expected that the aquatic ecosystem will be negatively affected as a result of the preferred alternative. 4.16 Cumulative Impacts 4.16.1 No Action Alternative Cumulative impacts that have occurred in the project vicinity include the initial channelization of the lower Cedar River into Lake Washington; the lowering of Lake Washington by approximately 9 feet (2.7 m) due to the construction of the ship canal; extensive filling and urban development that has occurred in the floodplain; construction of the dams at Chester Morse and Landsburg; the dramatic loss of riparian vegetation and habitat due to development and bank protection measures; and, the increased frequency and amplitude of flooding due to development and channel narrowing. All of these cumulative impacts have severely reduced the viability of fish and wildlife populations in the Cedar River basin. The no action alternative will not change any of the cumulative impacts that have occurred already in the area, but may exacerbate impacts to fish, wildlife and people from increased flooding in the future. :E 4.16.2 All Dredging Alternatives As described above, many cumulative impacts have already occurred in the project vicinity. A project that involves dredging, levee/floodwalls, and modifications to the south Boeing bridge will continue the existing channelization of the river while reducing flooding effects to the human environment. Fish and wildlife populations do not significantly utilize the immediate project area. This preferred alternative will help alleviate negative impacts that have already occurred such as stormwater runoff of pollutants from Boeing and the Renton Airport, and is not expected to add a significant adverse impact above and beyond the cumulative impacts that exist. This project will assure continued access for anadromous fish into and from the upstream river areas and will reduce the likelihood of stranding during flooding in Renton. Table 4. Summary of Impacts Element of the Environment No Action Existing Channel Minimal Dredge Moderate Dredge Deep Dredge Short-term; Constr. & Maint. Geology/Soils/Sedim ents NC NC Water/Water Quality NC Sockeye Salmon NC --- NA Chinook Salmon NC NC NC NA Coho Salmon NC NC NC NC NA Steelhead Trout NC NC NC NC Resident Trout NC NC NC NC NC Lon fin Smelt NC + + + NA Prickly Scul in NC + + ++ Coastrange & Torrent Scul ins + NC Mountain Whitefish NC NC NC + + NC Northern S uawfish NC NC + + NC Lar escale Suckers NC NC + + NC Peamouth Chub NC NC + + NC Three -spine Stickleback NC NC + + NC Brook Lamprey NC Non -Native Fish NC + + + NC Aquatic Invertebrate Diversity & Abund. + NC Wildlife NC + + + + Riparian Oriented Birds NC + + + + NC Open Water/Ground Birds NC - NC Bald Eagles NC NC NC NC NC NC Riparian Vegetation NC + + + + NC Aquatic Vegetation NC + + ++ Cultural Resources NC NC NC NC NC NC Land Use/Recreation NC NC NC NC Transportation + + + + Air/Noise/Light NC NC NC NC NC Aesthetics NC NC NC NC Public Services NC + + + Public Health & Safety NC + + + NC - slight negative impact or change from existing condition moderate negative impact or change from existing condition large negative impact or change from existing condition + slight positive impact ++ moderate positive impact NC no change or negligible change NA not applicable _______ ___ _________ NE 3rd v o� — — — — —_ -- — — — — o� L 5 Zlst St _ ___ _________ NE 20th St. NE 20lh ------_— _-------- —_ �z E� 5� <NEi — _ _ _ _ 's O th NE 17Upt Wni ________ _- ________-__= l,tna o _ - 4 -- _-_ __ _ __--- NE 12thS a a NE 12U St ---_ g c 11U H. r — --- — — - = low $sue St. 11th 3 tom{ Ih L 1 3 NE t0lh PI. NE loth ln. � HE SE NE 9fh St. E 8U PL E a 2 �_ a 9U Cl. N Blh St. F fitn a. NE etn St $ HE 7th -Z HE"a�Z $ c 6 Cl ` NE f: x 61h z a o 61h St. J N 61h S1. NE 6U o o N Sth St, NE �p a h� p. m 8 SOUTH BOEING BRIDGE LLJUJ N 4U SI. ® P NE 4tn St. m NE am i. NE tlh St '�d yE NE 7rd PI Ai earl Wa ®� � NE 2nd St S Tobin St S 2nd St d t S Id Sl S 3rd % ®�� ✓ LJ�mT 'bk Y� v a NARCO SE SU St SITE sy O Wm cv 8tq � h a 11 \\ 5 Renion vilage PI ye P FIGURE 15: PROPOSED HAUL ,..=2000' �000 ROUTE FOR DREDGED MATERIAL 1v Fran .air- 40 Z 71 d -irr ..w- c Wn -wv 5. MITIGATION AND MONITORING PLAN The Corps has selected the minimal dredging alternative (4 feet) as the preferred alternative and the proposed mitigation and monitoring plan reflect the impacts identified for this alternative. However, the local sponsor previously expressed an interest in pursuing the moderate dredge alternative, possibly after initial construction if the sedimentation rate in the channel requires more frequent dredging than is anticipated. Therefore, after discussing mitigation for the preferred alternative, Section 5.7 was included in the draft EIS and discusses likely additional mitigation that would be required for the moderate dredge (6 foot) alternative. This section has been retained in the final EIS to show the differences between the alternatives. 5.1 Avoidance of Adverse Impacts For the preferred alternative, impacts have been avoided to the maximum extent practicable while still accomplishing the project purpose of 100 year flood control along the lower Cedar River in Renton. The delta will not be dredged as a part of initial construction because it does not affect flood control levels and may provide significant environmental values to fish and wildlife species. The vegetation along the right bank between Logan Avenue and the south Boeing bridge will be left intact because of the riparian benefits it provides. Headcutting will be avoided or significantly reduced by the additional dredging upstream of Logan Avenue to bring the dredged slope up to the existing grade. This will prevent rapid sediment movement upstream of Logan Avenue following construction and maintenance dredging and avoid impacts to spawning salmon and their eggs. 5.2 Minimization of Adverse Impacts The preferred alternative minimizes dredging induced impacts to the maximum extent feasible. It provides a balance between dredge depth and levee height to maximize flood control while reducing the extent of lake backwater by minimizing dredge depth to to 4 feet (1.2 m). Possible adverse impacts from the placement of riprap along the left bank for 400 feet (120 m) between Logan Avenue and the south Boeing bridge have been minimized by placing riprap only below the OHWM and during construction the rock will be staggered, rather than creating a smooth rock face, to create holding areas for adult salmon. The construction and maintenance work window (for in -water work) has been voluntarily reduced to June 15 - August 31, rather than the usual June 15 - September 15 window because of the early sockeye and chinook adult migrants that enter the river in early September. 5.3 Rectification of Adverse Impacts Adverse impacts that can be rectified during and after construction include impacts to riparian vegetation from the construction of levees. Existing vegetation along the left bank will be removed during construction of the sheet -pile floodwall and rock toe to protect this bank. This impact will be rectified by replanting vegetation along the bank, above the rock revetment. However, a temporal loss of vegetation will still occur because the existing trees along the left bank are more than 20 years old. Vegetation along the left bank will be salvaged, and replanted in other locations near the river bank, to the maximum extent practicable to rectify adverse impacts from the loss of this vegetation. 5.4 Unavoidable Adverse Impacts Unavoidable adverse impacts remaining after avoidance, minimization and rectification of adverse impacts are the following for the 4 foot (1.2 m) dredge: 1) Loss of poor to moderate quality adult salmon (sockeye, chinook, coho and/or steelhead) spawning habitat between 1000 feet (300 m) and 3300 feet (1000 m) upstream of the mouth, which will likely become embedded with sands and finer sediments due to the lake backwater area increase. A maximum of 235 redds have been observed in this area during the salmon spawning season, so effective loss of habitat is estimated to be 2560-3840 ft2 (235-352 m2). 2) Periodic loss of approximately 45,000 feet2 (4100 m2) of bank scour holding areas for adult salmon, juvenile salmon/trout and resident trout. This habitat will be lost immediately after periodic maintenance dredging due to the trapezoidal shape of the dredged channel. It is expected that during the first winter season after dredging, the channel will readjust itself and create bank scour pool habitat. The 253,000 ft2 (5.8 acres or 23,230 m2) of increased lake backwater will provide additional lower velocity holding habitat below 3300 feet (1000 m) from the mouth, but will not provide any effective holding habitat upstream. 3) Loss of 253,000 feet2 (5.8 acres or 23,230 m2)of possible coastrange and torrent sculpin habitat due to lake backwater increase; this habitat will now be suitable for prickly sculpin and will increase prickly sculpin habitat by an equal amount. An increase in prickly sculpin habitat and population will likely cause a decrease in sockeye and chinook fry survival in the lower river. 4) Probable decline of brook lamprey populations due to periodic maintenance dredging operations. 5) Probable decline in aquatic invertebrate diversity and abundance due to periodic maintenance dredging which will remove invertebrates during their maximum growth period. Also, the increase in lake backwater will reduce habitat for organisms that prefer higher velocities while increasing habitat for organisms that prefer lower velocities. Therefore, diversity and abundance of aquatic invertebrates are expected to decrease. 5.5 Compensatory Mitigation for Unavoidable Impacts To compensate for unavoidable impacts, the Corps proposes to: (see Figures 16,17&18) 1) Plant riparian vegetation along both banks. Along the right bank from the south Boeing bridge down to the mouth, in approximately a 10-15 feet (3-4.5 m) wide. This will replace predominantly non-native vegetation and lawn with approximately 52,000 square feet (4,821 m2) of native riparian vegetation. On the right bank, this vegetation will include willows, Oregon ash, mock orange, snowberry, salmonberry, currants, salal and other species. These plantings will have several public access openings to allow park users to view and access the river, if desired. On the left bank, willows will be planted riverward of the floodwall from Logan Avenue down to approximately 2000 feet (600 m) from the mouth, in approximately a 5-10 feet (1.5-3 m) wide strip. These plantings will temporally replace vegetation lost on the left bank during construction and also contribute insects and detrital material to the river to compensate for possibly reduced aquatic invertebrate production. Additionally this riparian vegetation because of its roots and downed limbs/trees will likely create scour pools for additional adult salmon holding habitat. On the right bank the trees will be planted on 20 foot centers, and the shrubs will be grouped with the trees; approximately 6 shrubs per tree. Groundcover will be planted on 3 foot centers. This planting scheme will provide a total of approximately 200 trees, 1200 shrubs, and 3500 groundcovers of various types. The openings for public access and viewing will be approximately 30 feet wide, with a minimum of 4 access locations provided. 2) Create a groundwater fed pool and side channel at an upstream floodplain location with groundwater near the surface (upper Elliot levee site, see Figures 17&18). This pool and side channel will be connected at the downstream end to the Cedar River to allow use of the channel by both adult salmon for spawning habitat and juvenile salmon for winter refuge and rearing. The channel will be approximately 9000 ft2 (826 m2)7 in size with additional pond habitat. It is expected that this channel will replace the poor to moderate quality spawning habitat lost due to the project and will additionally increase survival for the eggs in the gravel, over existing conditions, and will compensate for probable increased predation in the lower river. Survival of the eggs will be increased because the channel will have moderate velocity flows except during flows >6300 cfs and will not be scoured as easily as mainstem areas. Native trees and shrubs will be planted (or left in place) in two acres surrounding the side channel and pond. ' The groundwater fed channel will be oversized to allow for less than complete spawning coverage. It is expected that only 50% of the channel will actually be used for spawning. This will adequately compensate for lost spawning habitat, as well as providing additional area for increased production of fry. :. Studies are currently going on at the upstream mitigation site to determine the depth to groundwater and the flow during summer. Preliminary investigations indicate that the groundwater ranges from 3-8 feet (0.9-2.4 m) below the surface in the area of the proposed channel. The site is in approximately the 10 year floodplain and would begin receiving water at flows above 6300 cfs. All measures to protect the site from flood scouring or deposition will be investigated. The channel will be designed to ensure that it functions as a moderate velocity channel during most river flows and to avoid the need for continued maintenance to keep the channel functioning. 3) Provide mainstem rearing habitat for chinook fry by either of the following: a) Place LWD in the mainstem Cedar (for approximately 500 linear feet) adjacent to the upstream groundwater fed channel site for chinook rearing. Chinook fry survival will be reduced and this habitat improvement will create an area of reduced velocity for feeding and cover for chinook fry as they rear in the mainstem river. Or b) Revegetate and place LWD at the levee at the Maplewood Golf Course to provide cover and rearing habitat for chinook. 5.6 Monitorina Plan In order to confirm the extent of impacts on key species and determine if the mitigation plan is successful, monitoring will be conducted for a period of five years. Monitoring of the mitigation elements will include: 1) In years 1,2 and 5 after construction, the riparian vegetation plantings will be evaluated for percent cover, canopy cover over the river and percent survival. Percent cover must be in the range of 40-60% in year 1, 75% in year 2 and 80-90% in year five. Shrub and some tree canopy cover by year five should be within 5% of the cover found upstream of the south Boeing bridge where riparian vegetation already exists. Percent survival should remain steady at 90-95%. If excessive mortality occurs in year 1, the contractor will be responsible for replacing plants. It is assumed that the contractor will provide supplemental watering during year 1. After year 1, the City of Renton will be responsible for supplementing if the plants continue to die. Monitoring will occur during the August -September timeframe to encompass the maximum growth of each season. Photos and a brief report will summarize each year's findings. In connection with the vegetation monitoring, bird use of the project area will be monitored. Specifically, bird species and numbers will be monitored on the delta, park and riparian zone at varying times of day (early morning, mid -day, evening times monitored each month) in years 1 and 2 after construction. Effort will be focused on the lower 3900 feet (1200 m) of the river (below the south Boeing bridge), to specifically determine changes that may affect airport operations. 2) In years 1,2 and 5 after construction, the side. channel will be evaluated to determine: if excessive sediment embedding has occurred, if access is sufficient to allow adult salmon utilization and the canopy cover from riparian plantings. The channel will be constructed with a gravel substrate. The sediment will be monitored to determine if sediment accumulation has occurred, to what depth and what size of substrate. 18% or more embedding fine material (sands and silt) is unacceptable and egg survival is significantly reduced in such areas . The channel will also be periodically monitored to determine use by adult salmon for holding or spawning (redd counts, live fish counts). Canopy cover will be measured during August -September timeframe to encompass the maximum growth of each season. By year 2, canopy cover should be in the range of 50-60%, by year 5, canopy cover should be 70-80%. Photos and a brief report will summarize each year's findings. If during the five year monitoring period, it is determined that any of the mitigation elements are not successful; for example, the riparian vegetation is not growing/surviving or the side channel has filled with sediment, then a contingency plan will be implemented. Contingency actions have not yet been determined, but will be determined during the permitting process, with the appropriate state and federal resource agencies and the Muckleshoot Indian Tribe. It is expected that additional plantings to replace dead plants, or an alternate mitigation site for salmon spawning would need to be accomplished as a contingency measure. The evaluation of impacts in the planning process and this EIS indicates, based on three years of data, that longfin smelt spawning will not be significantly affected by the construction of a flood control project. In order to confirm and document that this is the case, longfin smelt spawning will be monitored. Eggs will be collected for longfin smelt in years 1,2 and 4 following construction (one low year and two high spawning population years, 1999, 2000, and 2002). Eggs will be sampled at 300 meter intervals similar to the study conducted in 1996. Three samples will be collected at each transect up to 1800 meters from the mouth on a monthly basis from late January to May. Egg abundance and distribution will be compared to the pre - dredging studies. In order to ensure that the mitigation measures are adequate, sockeye redd counts will be conducted yearly for five years from Wells Street to the mouth. These counts will occur once monthly in October, November and December (if possible). Spawning distribution will be compared to counts prior to construction. The side channel will also be observed for spawning as described above. 5.7 Impacts and Mitigation for Moderate Dredge Alternative The moderate dredge alternative would not avoid and minimize adverse impacts to the extent that the preferred alternative (minimum dredge alternative) does. The same and additional unavoidable adverse impacts would likely occur compared to the preferred alternative; primarily due to the increased area of lack backwater that would result from a deeper dredge depth. Expected additional unavoidable adverse impacts are: 1) Loss of poor to good quality adult salmon (sockeye, chinook, coho and/or steelhead) spawning habitat between 1000 feet (300 m) and 4200 feet (1300 m) :: upstream of the mouth, which will become embedded with sands and finer sediments due to the lake backwater area increase. A maximum of 435 redds have been observed in this area during the salmon spawning season, so effective loss of habitat is estimated to be 4740 -7100 ft2 (435-650 m2). 2) Loss of 352,000 ft2 (8 acres or 32,320 m2) of probable coastrange and torrent sculpin habitat due to lake backwater increase; this habitat will now be suitable for prickly sculpin and will increase prickly sculpin habitat by an equal amount. An increase in prickly sculpin habitat and population will likely cause a decrease in sockeye fry survival in the lower river. Other unavoidable adverse impacts would be similar to that described for the preferred alternative in Section 5.4. In order to adequately mitigate for these additional impacts, it is expected that increasing the size of the proposed groundwater fed pond and channel (Section 5.5) would suffice. Increasing the size of the pond/channel to 18,000-20,000 ft2 (1652-1840 m2) and increasing plantings to three acres surrounding the pond/channel should adequately mitigate for the increase in lake backwater area due to additional dredging depth. Additional rearing habitat for chinook would also need to be created to compensate for reduced survival due to predation in the lower river. 3 2 N ...........".. .. : • ......................` 0 i.. '' j ..... N II n -4 00 ::.F i co •, i OD II `� •••..✓ ::•:;•>�.;,: i is x; ... l 4D . O i'`. • ...... �t, ' I . s.• I +. .. i r , I I 1---- lT1 '•. w t N NJ I , N .•'' i �p I x a K O \ / OI x /— f I • ...... r k I x N �..... N N ; Ln i > N .............. ........... i �X i i — O is '•:! k i !in . I O ' :..... x N N r• C U.S. ARMY ENGINEER DISTRICT, SEATTLE MITIGATION PLAN CORPS OF ENGINEERS SEATTLE, WASIANGTON SCALEI 1" = 100' LEGEND CEDAR RIVER FLOOD CONTROL FIGURE 16: 00 MITIGATION PLAN 00 ROSES SHEET 1 CATTAILS RENTON WASHINGTON ^ h DATE AND TIME PLOTTED: 04-FEB-1997 15:26 ��. �:•+ '�•-(.� WILLOWS, CURRANTS [ • 97JAN30 DESIGN FILE. icOdesignsfcrfc0orch0crfcoo0b.dgn l'.r °x M. MAR TZcm —IT 4 3 2 u m c - - - --- ------------------------------------------------------------- -- -- - - ----------------- -- - ------- - ------- - / ` 3 2' Ul. o ' � ~ . _ . ID _ . � . / � . co . _ toLn . 00 ------ | ' WILLOWS ONLY THIS SIDE _ . — . � CID / / _ / / . / 4 � / 0) /' \ K)U.S. ARMY ENGINEER DISTRICT, SEATTU CORPS OF ENGINEERS SEATTLE, WASH14GTONLEGEND | ' CEDAR RIVER rumn oowrnn U | / FIGURE M(CONT) IWITIGATION PLAN ' - DATE AN~ TIME PLOTTED: .~.~~.. .~~ ^---===^ . _ co w Lake Mitigation Site Legend Streets Cedar River Mitigation Site € Golf Course Source Information Lake boundary information obtained from Washington Rivers Information System (WARTS) database, Washington Department of Wildlife (WOW). City boundaries, streets, park and river information obtained from King County. Cedar River Section 205 Study Mitigation Site, Elliott Levee FIGURE 17: Upstream Mitigation Site Section 22, Range 5 E, Township 23 N +29 acre site; +5 acres required for spawning channel and access. Site diagram not to scale. Ce�ar gf�er Maple Valley Nighwa Y LU CIO N It is understood that, while the Corps of Engineers and information suppliers have no indication or reason to believe that there are US Army Corps of Engineers inaccuracies in information incorporated in the basemap, THE CORPS AND ITS Date: 6/6/97 A300 0 300 600 Feet SUPPLIERS MAKE O MERCHANTABINO LITY OR FITNTATION OF ESS pOR A PARTICULAR USEND, INCLUDING BUT DT LIMITED , NOR ARE TO ANY Preparers LDD SUCH WARRANTIES TO BE IMPLIED WITH RESPECT TO THE INFORMATION, DATA, OR SERVICE FURNISHED HEREIN. 9f' -- --� y ' TYPICAL PLANTING SCHEME FOR RIPARIAN VEGETATION CHANNEL CONNECTS AT DOWNSTREAM END TO RIVER T GROUNDWATER P D FIGURE 18 ' N. SIDE CHANNEL PLAN PREVIOUSLY USED AT ELLIOlr LEVEE 0 (FROM KING COUNTY) AL -1 F 4 9 AIL PL IE7 -W. ItT U7' Zk l6t� 6. STATUS OF COMPLIANCE WITH APPLICABLE LAWS AND REGULATIONS Throughout the planning process, coordination with representatives from federal, state and local agencies, and the Muckleshoot Indian Tribe has been conducted. Table 5, below, summarizes the status of compliance with various applicable laws and regulations. This proposed project will be in compliance with the National Environmental Policy Act (NEPA) and the State Environmental Policy act (SEPA) as a result of this EIS process and the serious consideration of comments received. The public review of the draft EIS revealed that there was no significant controversy about the proposed project and preferred alternative. In general, most agencies and individuals support the project (see Appendix A). There were concerns about impacts to chinook salmon, especially in light of their potential listing as an endangered species. There were also requests for more information about the proposed mitigation site. In several sections, information has been added to clarify confusion which some commentors had about statements made in the draft EIS. Interested parties and agencies will continue to be involved in the final designs of the project and mitigation. This proposed project will be in compliance with the Fish and Wildlife Coordination Act (FWCA) and Endangered Species Act (ESA) per consultation with the U.S. Fish & Wildlife Service (FWS). The Corps has submitted a biological assessment (BA) of potential effects of the project on threatened or endangered species and the FWS has concurred with that assessment. The FWS has prepared a draft and final FWCA Report and the final report is enclosed as Appendix B to this final EIS. Responses of the Corps to the comments and recommendations within the final FWCA Report are included in Appendix B. The Corps has consulted with the State Historic Preservation Office (SHPO) on the possible effects on cultural or historic resources. The SHPO has concurred that no effects are expected (enclosed with DPR). The Corps is conducting an evaluation and review of compliance with Section 404 of the Clean Water Act, the Coastal Zone Management Act, and Executive Orders 11988 and 11990. The local sponsor is required to obtain the following permits prior to construction of the proposed project: Water Quality Certification and Water Quality Modification Hydraulic Project Approval City of Renton Shoreline Substantial Development Permit City of Renton Grading Permit 94 Table 5. Summary of Consistency of the Preferred Alternative with Applicable Laws and Regulations. Laws & Regulations Relating to Issues Addressed Consistency of Preferred the Proposed Alternatives Alternative National Environmental Policy Act Requires all federal agencies to Consistent (NEPA) 42 U.S.C. 4321 et seq. consider the environmental effects of their actions and to seek to minimize _________________________ne ative im acts ----p--------------------------------------- State Environmental Policy Act Requires state agencies to consider the Consistent (SEPA) RCW 43.21 environmental effects of their actions _ _—_________—and actions —of applicants____ Clean Water Acts (CWA) 33 U.S.C. Requires federal agencies to protect _ _ __ Will be consistent per 1251 et seq.; Section 404 waters of the United States. Disallows 404(b)(1) Evaluation the placement of dredged or fill material into waters (and excavation) unless it can be demonstrated there are no _ _ _ _______reasonable_alter_natives._ Clean Water Act Section 401 _____ Requires federal agencies to comply _ __ Will be consistent with permit _________________________with state water quality standards _____—_____ requirements Fish and Wildlife Coordination Act 16 Requires federal agencies to consult _____ Consistent U.S.C. 661 et seq. with the US Fish & Wildlife Service on any activity that could affect fish or ------------------------------------------------------------------------ wildlife. Endangered Species Act 16 U.S.C. Requires federal agencies to protect Consistent 1531 et seq.; listed species and consult with US Fish & Wildlife or NMFS regarding the _________________________proposed action. — — — — — — — — — — — — — — National Historic Preservation Act 16 — — Requires federal agencies to identify — — — — — — — — — — — — — — — — — — — -- Consistent U.S.C. 461; and protect cultural and historic __________________________ resources Executive Order 11988, Floodplain --------------------------------------- Requires federal_ agencies to consider Consistent Management, 24 May 1977 how their activities may encourage __________________________future development in flood dins____________ Executive Order 11990, Protection of Requires federal agencies to protect ______ Consistent Wetlands ------------------------------------------------------------------------- wetland habitats. 95 Laws & Regulations Relating to Issues Addressed Consistency of Preferred the Proposed Alternatives ----------------------------------------------------------------------- Alternative Shoreline Management Act (SMA) State law implementing the Coastal Consistent and Shoreline Management Program Zone Mgmt Act requiring local (SMP) RCW 90.58, WAC 173-14 jurisdictions to plan and protect shorelines. Coastal Zone Management Act Requires federal agencies to comply Consistent (CZMA) 16 U.S.C. 1451 et seq.; 15 with state and local plans to protect and CFR 923 ------------------------------------------------------------------------ enhance coastal zones and shorelines. Washington Hydraulic Code Requires proponents of developments, Will be consistent with permit etc to protect state waters, wetlands requirements ------------------------------------------------------------------------ and fish life. Indian Treaty Rights Protect Indian tribes' property, water Will be consistent per public rights and usual and accustomed review process --------------- __________fishin areas. ------------------------------------------ Cedar River Basin and Nonpoint Interagency basin plan that encourages Consistent Pollution Action Plan reduction of flooding, water quality enhancement and fish and wildlife rotection. We rZ Lr. L- re; 6;6 -L loc. b0i rp�_� M6 _TIz ON -ZA 4-,tx,� L line � f V, I L - � mil., - - m!'m pi I No- arl, -4r grjo id REFERENCES Beauchamp, D.A. 1995. Riverine predation on sockeye salmon fry migrating to Lake Washington. North American Journal of Fisheries Management. 15: 358-365. Bucher, Willis & Ratliff. 1995. Renton municipal airport master plan update. Prepared for the City of Renton. Franklin, J.F. & C.T. Dyrness. 1973. Natural Vegetation of Oregon and Washington. USDA Forest Service General Technical Report PNW-8. Portland, OR. Groot, C. & L. Margolis. 1991. Pacific Salmon Life Histories. University of British Columbia Press, Vancouver, BC. 564 pp. Harza Northwest. 1994. Distribution of longfin smelt (Spirinchus thaleichthys) eggs in the Cedar River, Washington. Report to the City of Renton. King County Surface Water Management. 1993. Cedar River Current and Future Conditions Report. Seattle, Washington. Malick, J.G. 1977. Ecology of benthic insects of the Cedar River, Washington. Doctoral dissertation, University of Washington, School of Fisheries. 188 pp. Martz, M., F. Goetz, J. Dillon & T. Shaw. 1996a. Lake Washington ecological studies, study element Il: early lake life history of sockeye salmon (Oncorhynchus nerka) in Lake Washington, year 1, 1994, final report. U.S. Army Corps of Engineers, Seattle District. Martz, M., J. Dillon, T. Shaw & F. Goetz. 1996b. Lake Washington ecological studies, study element II: early lake life history of sockeye salmon (Oncorhynchus nerka) in Lake Washington, year 2, 1995, final report (supplement to year 1). U.S. Army Corps of Engineers, Seattle District. Moulton, L.L. 1970. The 1970 longfin smelt spawning run in Lake Washington with notes on egg development and changes in the population since 1964. Master's thesis, University of Washington, School of Fisheries. 84 pp. Moulton, L.L. 1974. Abundance, growth and spawning of the longfin smelt in Lake Washington. Transactions of the American Fisheries Society. 103(1): 46-52. Sibley, T. & R. Brocksmith. 1996a. Lower Cedar River Section 205 longfin smelt study, Final Report. Report to the U.S. Army Corps of Engineers, Seattle District. University of Washington, School of Fisheries. 97 Sibley, T. & R. Brocksmith. 1996b. Lower Cedar River Section 205 Study aquatic invertebrate study, final report. Report to the U.S. Army Corps of Engineers, Seattle District. University of Washington, School of Fisheries. Tabor, R. & J. Chan. 1996a. Predation on sockeye salmon fry by piscivorous fishes in the lower Cedar River and southern Lake Washington. Western Washington fishery resource office, U.S. Fish & Wildlife Service, Olympia, WA. Tabor, R. & J. Chan. 1996b. Predation on sockeye salmon fry by cottids and other predatory fishes in the lower Cedar River, 1996. Western Washington fishery resource office, U.S. Fish & Wildlife Service, Olympia, WA. Wydoski, R.S. & R.R. Whitney. 1979. Inland Fishes of Washington. University of Washington Press, Seattle, Washington. 220 pp. sr Q J? eign d S-uf EA 4. GLOSSARY anadromous - species of fish that mature in ocean waters but return as adults to spawn in freshwater lakes and rivers; includes salmon and trout species among others. Young fish spend a varying amount of time in freshwater before migrating to the ocean. adfluvial - species of fish that mature in freshwater lakes but spawn as adults in rivers and streams; includes longfin smelt in Lake Washington, resident cutthroat trout, kokanee and other species. Eocene epoch - time period approximately 40 million years ago in the Tertiary period. Characterized typically by warm water/climatic species often found in sedimentary layers from freshwater and seawater deposits. igneous - rocks formed by volcanic and magmatic processes; can be formed by volcanic flows/explosions (extrusive) or magma intruding into other crustal materials (intrusive) large woody debris (LWD) - logs or rootwads from trees, typically larger than 10 cm in diameter and 2 meters in length. LWD substantially contributes to habitat forming processes and is the largest contributor to forming pools and preventing movement of spawning gravel limnetic - the openwater zone in lakes or oceans away from shore, characterized by water deeper than 10 feet. littoral - the nearshore shallow water areas on the edges of lakes or oceans. ordinary high watermark (OHWM) - the elevation of a normal yearly occuring high water in rivers or lakes, typically defined by limit of vegetation on banks pelagic - species of fish, mammals or invertebrates that inhabit the surface to mid -depth waters of a lake or ocean. Puget Sound Dredged Disposal Analysis (PSDDA) - a process that defines standards for dredged material analysis and limit of contaminants allowed in material that will be dumped at designated openwater sites in Puget Sound. Implemented by the Washington Departments of Ecology and Natural Resources, the Environmental Protection Agency and the U.S. Army Corps of Engineers. redds - the "nest" a female salmon excavates in stream or lake substrate to lay her eggs. Redds are excavated with the tail and typically have successive layers of gravel that are cleaned and washed across the egg laying area. sedimentary- rocks formed by sedimentary deposits which could have been placed by lakes, rivers, oceans, glaciers, wind, oceanic oozes, evaporation, etc. metamorphic - rocks formed when parent material is subjected to heating or pressure, or chemically active fluids within the solid state. "sole source" aquifer - a groundwater source used for drinking water by a municipality or other facility that is the only drinking water supply for that municipality, etc. 100 APPENDIX A COMMENTS RECEIVED ON DRAFT EIS WITH RESPONSES FROM THE CORPS Cedar River Section 205 Flood Damage Reduction Study Responses to Specific Comments Received on the draft EIS: 1. Issue is addressed in the Detailed Project Report (DPR) which was reviewed by Boeing: also available from Linda Smith, Corps of Engineers, (206) 764-6721. The Corps has never guaranteed that Boeing will be provided uninterrupted use of their bridges during all inclement weather events after construction of the project. Boeing currently experiences significant closure periods during and following flood events. 2. Several commentors asked about whether delta dredging is required for placement of dredged material on a barge, or if maintenance dredging may require delta dredging, or if the delta would continue to grow and may reduce flood control in the future. The Corps and the City of Renton have determined that the "Narco" upland disposal site is suitable and available for at least 20 years following construction. Dredging the delta is not necessary when using a hydraulic suction dredge operation. The Corps has assumed that if the City of Renton, in the future, wishes to dredge the delta for barge access, that they will apply for a separate permit to complete that action. Dredging the delta is not considered necessary for the federal project. The Corps recommends that the City pursue a long-term dredged material management plan with the natural resources agencies, that may include designating a disposal site in Lake Washington. The delta is expected to continue to receive significant amounts of sediment which will deposit out in Lake Washington. The outer edge of the delta drops off rapidly into water depths of 50 feet or more. It is not expected that the delta will significantly affect flood control at any point in the future. 3. Engineering design details will be addressed during the plans and specifications phase of the project. The Federal Government's level of acceptable risk may differ from Boeing's. 4. Issue is addressed in the DPR, see number 1, above. E 3 1 4 Tiw 6o.IN Compn y Po sax 3707 SWW. WA M124-22M May 5, 1997 Ms. Unda Smith, Study Manager Civil Projects U.S. Army Corps of Engineers P. O. Box 3765 Seattle, WA 98124 Subject: Cedar River Dredging EIS Draft Detail Project Report Dear Ms. Smith. Thank you for the opportunity to provide additional comment reg the Cedar River Dredging EIS, Draft Detail Project Report. Also, you for your past consideration of comments Boeing made regar plantings of the Delta area. First, Boeing would Ilk@ to sham our support for the diligent work one by the Corps, the City of Renton and other stakeholders of the Cat a River Dredging '205" Project. While, Boeing enthusiastically supports the recommended and p eferred Alternative C - Minimum Dredge of four feet, additional informati n from the Corps Is required to provide assurances that this aftemativn III provide a level of flood management that protects Boeing's abil' to have uninterrupted production after construction of the project. There bra, we would like for the Corps to provide us with modeling estimates of the bridge closure duration occurring under each alternative, for the 0, 20, 50 and 100 year recurrent event In order that we may better and rstand the risks associated with each altemative and potential Impacts t production for planning purposes. Boeing continues to believe the Dena could require periodic dre ging for containment Purposes and we would like the opportunity to cont us to discuss how d would be addressed K that became evident. Boeing also believes the Issue of channel maintenance should e addressed and resolved during lire plans and Specification phas of the project to Include information regarding acceptable levels of risk to Boeing and the airports operation. Another Important part of Boeing's ability to deliver planes to ou customers is the preservation and protection of the Compass Roll o e. The preferred alternative will need to protect and assure that no mot I objects A-1 capM :Crnr. (7ry.�i, r -.TAs TO -M 79n ss7s (Le. metal in levies or a wall) are located within 150 feet of the Co npass Rose. Again, thank you for the opportunity to comment of this project. Being continues to support the efforts of the Corps to date and looks fo rd to wonting with the many stakeholders of the Cedar River Dredging '205' Project. Sincerely. % BOE/N� Elizabeth J. Warman Manager, Local Government Affairs - Puget Sound cc: Merl Mertz Ron Stratka, City of Renton Ross Hathaway, City of Renton Project Manager Mary Armstrong Terry Lewis Mehdi Nakhjiri Paul Crane Gerry Bresslour A-2 ..ES. _.dSL_. 5. This issue is addressed in the DPR, see number 1, above. It is not expected that any fine tuning of levee length versus floodwall length will change any effect on the environment. The use of levees on the left bank immediately downstream of Logan Avenue could create access difficulties to some businesses located adjacent to the airport. The use of levees or floodwalls will be designed to minimize any safety concerns. 6. During plans and specifications, all engineering elements will be designed to comply with the Americans with Disabilities Act. This will not affect the evaluation of project impacts on the environment. 7. Park design issues will be coordinated with the City to replace any public amenities damaged or relocated as a result of the project. :; CITY OF RENTON Planning/Ruihling/f uhlic Works Department Jesse Tinner. hlaror Gregg Zimmerman P.F... Administrator May 9, 1997 Linda Smith, Project Manager U.S. Corps of Engineers, Seattle District P.O. Box 3755 Seattle, WA 98124-2255 SUBJECT: CEDAR RIVER 205 PROJECT DRAFT F,NVIRONMENTAL IMPACT STATEMENT (DEIS) REVIEW COMMENTS Dear Linda: Please find herewith the official comments from the City of Renton on file Cedar River Section 205 Flood Damage Reduction Project Draft Environmental Impact Statement (DEIS). These comments include those from the Municipal Airport, Parks Department, Surface Water Utility, and all other Departments in the City's Design Team. Several of these comments are very similar to those submitted for the Draft Detailed Project Report. Thank you for the opportunity to review the document and give official comment. GENERAL COMMENTS: We are very pleased with the Draft EIS, and would like to restate our appreciation to the Army Corps for their hard work and patience. We fully encourage you to proceed to finalize the EIS as soon as possible. In this perspective, we intend that none of our comments are to slow the process, or unduly raise concerns. Please do not hesitate to call us if you need any clarification or want to discuss any of these issues. Sheet Pile Floodwall: a) The amount of shcetpile floodwall in the project will he minimized as much as possible, both due to cost issues and its unsightliness. Much of the alignment presently shown as floorlwall will be investigated to he replaced with type I levee, or type 1 levee corer) cJ roadway topped levee with steeper sides and guard mils. The exact segments of floodwalls to be actually constructed as levee will he worked out in file plans and specifications depending on allowable flexibility of configuratinn and the space available at specific locations. In discussions with the City of Renton Municipal Airport Manager, several segments have been identified as candidates for levees rather than floodwall including adjacent to the compass rose on the left hank and upstream of the South Boeing Bridge. 6 2) Issues Impacting the Parks Department: a) All ADA (Americans with Disabilities Act) requirements must be met, including access from the parking areas to the trail system. b) The plans reflect loss of a large open turfed area south of and adjacent to the picnic pavilion/play amenities that is currently utilized for touch football, Frisbee throwing, etc. This is an important component of the park which needs to he nccornrnodated as much as 7 b - g possible. c) The children's play area has been eliminated and needs to he reconstructed at another location in close proximity to the picnic pavilion and rest rooms. 200 Mill Avenue South - Rcnton, Washington 98055 ® nu. n.rw—... ,.. -.i. ", r,n.,.,.,..,,... A-3 RESPONSES: 8. Mitigation design will be conducted with the cooperation of the City. However, it must be recognized that current park plant materials downstream of the south Boeing bridge provide no habitat values for fish or wildlife and have a negative effect on fish habitat because they provide no shading, nutrient input or habitat forming material (woody debris). The mitigation design will take into account the need to provide effective replacement for lost habitat features as well as providing continued access for public use of the river frontage. 9. The City has had flooding problems on the trail beside the River for many years. There is not a Federal interest in dredging to deeper depths to further reduce the risk of the trail flooding. The Corps recommends that the City individually pursue constructing a small levee or pumping station to alleviate flooding under the Logan Avenue bridge. A-4 Linda Smith, U.S. Corps of Engineers Cedar River 205 Project Draft Detail - Review Comments Page 2 (1) It is unclear what the impacts will he if the trail is raised at a location where an existing ornamental water feature is constructed as part of the Senior Center. e) The proposed design elements for the Closure Structure and the physical location of the proposed structure are not aesthetically pleasing and create an opportunity for "creative" play where the potential for injury is increased. Further details and alternatives need to he investigated during plans and specifications. f) We recommend the trail system be designed so that it is not constricted at one elevation at the top of the levee throughout the park system. The trail should wind around, and vary in vertical elevation, as it does now in the existing park. It would he aesthetically desirable to have the final elevations or the berms (levees) vary in height(s) as do the existing berms throughout the park. This undulating effect is more natural and creates visual interest. In addition, the actual width of the benns need to vary because this is more natural looking in appearance and is visually appealing. A better example of the effect of whal Parks is trying to describe and what the Corps needs to achieve, would he to take a cross section or "slice' of the park from Logan street midge to the mouth of the river and raise that "slice" up to the required elevations for flood control purposes. We would like the future park to resemble what is currently in place now. We believe levees and berms are compatible and this effect can be achieved. g) Thnse levees inside the park that are to he covered with grass and will require mowing shall have 4)1:IV side slopes. As stated in previous documents, the maximum slope for the berms (levees) within file park area should be 4:1. This is the maximum slope upon which turf equipment can maneuver. Steeper slopes will be vegetated with shrubs and/or groundenver that do not need mowing, but will require more costly maintenance operation as the area will have to be raked, weeded, barked, etc. The exact locations of 4: I, 3:1 or 2:1 slopes within the park area needs to be dealt with in plans and specifications. As much of the levee as possible should have 4:1 slopes. h) Suggested native plant materials for lute compensatory mitigation need to be coordinated with Parks. For example, willows have an invasive root system which can impact utility systems and are also shallow rooted making it difficult to mow. It should also he noted that the City currently does not remove invasive species such as blackberries along the riverbank. The recommendation that the City remove these invasive species in addition to our routine park maintenance, constitutes an increase in workload and increase in maintenance costs. An environmental, mitigation related, justification for control of non- native species needs to be provided. This shnnld address the reasoning for any continuation of these controls after planted species becnrnes firmly established, particularly as it is offset by any negative impacts of this control program. i) The location and quantity of native plant materials also needs to he coordinated with Parks. Certain areas are better suited for more natural plantings It is also very important that the public not only have physical hilt visual access to the river. In addition, intensely planted vegetation increases the time and associated costs of maintenance requirements due In the additional Icaf drop and shade in the turf areas. i 1 In previous meetings with City staff, the recommendation for dredging further up -stream of Logan Street Bridge was discussed. Parks continues to recommend dredging up to Wells in 9 j k order to reduce the flooding impacts on the park/trail system and most importantly, to better address imminent life safety issues. If it is possible, please include a short discussion of this option, and the required mitigation for it. ..ES..-.JSL_. 10. Concur. The Corps is coordinating with the City of Renton to ensure that the proposed mitigation site conforms to the Master Plan and will not endanger either the existing spawning channel or the golf course. These issues will be addressed in detail during Plans and Specifications. 11. Historic sedimentation rates indicate that the river will fill in slower than the model predicted. However, the river will still experience increased lake backwater effects over most of the reach identified in this EIS. The increased lake backwater area will reduce spawning habitat and change the invertebrate community. The proposed mitigation is warranted for the expected effects. Linda Smith. U.S. Corps of Engineers Cedar River 205 project Drill Detail - Review Comments Pipe 3 k) The Parks Department his expressed a concern that this project does not presently propose to correct ftnoding of the riverside trail under Login Avenue on the right hank of the river (Renton Senior Activity Center side). In the design, the current and existing problem of time trail underpass being under water at Logan between six to seven months of the year may not change significantly. This underpass is critical to the trail user as the only other way to approach the trail on the north side of Login is to cross a rive (5) line highway located on a curve. In addition, this access point is a mid -block crossing creating Additional hazards. (It should also be noted that the Renton Senior Activity Center is located on the Cedar River Trail on the south side of the Login Street underpass. The Senior population is an avid user of this system and crossing a 5 lane road, on a curve, it mid -block is not recommended). We recommend the option of providing some measure of protection for this underpass he identified in the document. 1) The City'% primary choice of the recommended mitigation sites is known As the Cedar River Regional Park site (a few hundred feet upstream of the existing Elliott Levee spawning channel); and is also owned by the City of Renton. Additional title searches need to be completed along the river's edge to verify ownership of the entire parcel. An adopted Nlnsicr Plan is already in place for the future active and passive development of this 45 acre park site. Phase I construction will commence this year. m) The proposed mitigation elements must be coordinated with the adopted Master Plan and 10 1 - n requirements is outlined in the Transfer of Title and associated funding sources (Interagency Committee for Outdoor Recreation and Forward Thrust Funds). Very preliminary investigations indicate that a salmon spawning channel can be constricted on this site, if soft surface trails and interpretive signage are included as part of this project. A snft-surface trail system is consistent with the Master Plan, provides maintenance access, and is cost effective to maintain. We believe the proposed spawning channel in this locatinn is an excellent opportunity for education and interpretation. n) The Elliott Levee Site referenced in this document is located directly behind the City of Renton's Maplewood Golf Course. A spawning channel was developed approximately 2 years ago with additional improvements completed in the fall of 1996 due to storm damage in late 1995 and early 1996. These channel improvements were limited to the area as developed (distance from the north fence line of the golf course). These Additional improvements were expected to reduce the overall flood elevation and velocity through this reach, leading to a reduction in the frequency and severity of levee failure for the facility (Maplewood Golf Course). Any additional mridifications in this specific Area must lint conipionmise the integrity of the golf course mid the existing spawning channel. 3) Army Corps FIFO-6 Analysis, dredge cycle pralines, mitigation level: a) Per our more detailed comments submitted on the Draft Detailed Project Report (DDPR), the sedimentation analysis has an extremely conservative annual computational hydrograph which generates very large sediment loads. The modeled computational hydrograph introduces a shun period At the 500-year event flow annually. 'Ibis rcstills in a modeled 1 sediment load that will require rerlredging once every three years Historic indications ire that the channel will return to river -like condition in a fairly short period, then slowly shallow river time. This would indicate that whatever mitigation was hased on A dominantly lake -like condition for the lower channel, and a three year dredge cycle, may he significantly excessive. These include mitigation for the impacts to invertebrate density and same of the loss of spawning habitat. Since it may he difficult to withdraw much of the proposed mitigation, it may he warranted to phase the mitientinn in or establish mitigation A-5 RESPONSES: 12. The Corps disagrees with this viewpoint. While the delta will not be affected in any way by the proposed project, the discussion of threatened and endangered species must include any known information about these species in the project area. Bald eagles have been observed perching on the woody debris on the delta. 13. The Corps disagrees with this viewpoint. The proposed riparian plantings along the right bank below the south Boeing bridge are proposed for several reasons: 1) this vegetation will compensate for the expected loss of vegetation along the left bank; 2) this vegetation will contribute nutrients in the form of detritus to compensate for an expected loss of invertebrates due to dredging activities; 3) this vegetation will compensate for lost holding and hiding habitat for salmonids by creating a shaded riparian edge as well as providing the opportunity for the creation of bank scour pools associated with the vegetation; and, 4) the plantings of trees and shrubs are expected to reduce the use of the park area by gulls, geese and other nuisance birds. Overall, the placement of native riparian vegetation along the river corridor is expected to contribute in a positive way to the fish and wildlife use of the Cedar River. It would be extremely difficult and costly to monitor the change in resident fish population due solely to the placement of native riparian vegetation along the lower 3000 feet of the river versus benefits to salmon species which also may occur due to this vegetation. 14. Riparian plantings will likely provide similar habitat for woodland birds and some duck species as occurs upstream of the south Boeing bridge along the right bank. Bird use of this area has been observed and the typical species utilizing this habitat are: woodpeckers, chickadees, warblers, wrens, finches, etc. Currently, the park and the gravel bars in the river are heavily utilized by gulls, geese and other potentially hazardous birds. After the project, the gravel bars will be absent and the park will be less attractive to these potentially hazardous birds. The delta will still be attractive to these birds as will the airport runway. It is unclear if the City of Renton wishes the Corps to leave these areas as prime habitat for nuisance birds. The Corps has recommended that the City explore options for bird control, such as the use of netting to prevent birds from using the airport runway. The Corps believes that the removal of two prime areas of potentially hazardous bird use will tend to reduce the overall populations of these birds in the general area. 15. Specific editorial changes have been made as appropriate. The in -water work window has not been changed after consultation with the Washington State Department of Fish and Wildlife. The work window will end August 31 because the later portion of the window can be during the earliest portion of the sockeye and Chinook upstream migration. If during Plans and Specs, the Corps determines that the work window is insufficient to complete dredging, the Corps will consult with the appropriate agencies to determine a more acceptable work window that will not significantly affect migratory salmon. Linda Smith, I I.S. Corps of Engineers Cedar River 205 I'roject Draft Delail - Review Comments Page d credits for the mitigation done based on monitoring. Another method would be to relax some of the requirements to maintain riparian corridor vegetation along lite project reach. J) Delta Impacts: a) Some additional detail should be added to the discussion of expected project impacts to the see ,delta. This would include continued transport of a large portion of the sediment through the 2 project reach to the delta. A projection of delta growth with or without the project should he provided, impacts caused by delta growth to recreation, navigation and airplane safety should be discussed and an explanation as to why the delta is not included in the prnject. 12 b) While project impacts tQ the delta and the surrounding area should be discussed in the EIS; the discussion of the value of woody materials on the delta should not be included in the EIS. The delta, and its woody material, is specifically not part of the project, and assessment of the environmental value of this unntedil is separate concern and an issue to he addressed in a different forum. 5) Mitigation Vegr(atinn along Lower Channel: a) The proposal to place more vegetation along the lower channel than is presently there, may serve to disproportionately benefit salmon predator species; some of which will already benefit from dredging. During monitoring the net impacts, and mechanisms of this measure, need to be quantified, and the mitigation measure objectively analyzed. 13 The main function of the trees is to provide more habitat for invertebrates (both aquatic and terrestrial). Since this will provide a more or less constant supply of food, the resident fish of the lower channel may increase in population due to the increase in carrying capacity. If the lower channel will have an extended lake backwater condition, this will provide an increased constant foal supply for the slow water velocity species, many of which are predator species on salmonid. Invertebrates are likely the primary foal supply for many of these species. These species will have already beneruted front the dredging; increasing llte constant food supply may increase their population even further, thereby potentially increasing their impact on the pulses of transient prey species such as sockeye fry. An eventual understanding of the net impacts to the important species using the lower Cedar River would be hclpftd; this would, at sonic point, ideally, be used to optimize some preferred balance. 14 b) Increasing bird habitat adjacent a runway may not he helpful to these species. We need to he very careful not to increase the gull and waterfowl populations adjacent the airport. c) For the above reasons, we recommend taking a moderate approach to the plantings along the river. More openings (than are shown on the plans) from both the park side and airport would provide a diverse habitat, as well as making the plantings more visually pleasing and minimizing any potential negative impact on the salmon fry. 15 SPECIFIC EDITS: 6) Page ii, Iasi paragraph, second sentence Okn pner } p:rrnCraph J) Replace: "2500 cfs" With: "2200 cfs" 7) Pageiii,seennd paragraph,second sentence Replace: " in this EIS because it was not possible to the clearly " A-6 Linda Smith, U.S. Corps of Engineers Cedar River 205 Project Draft Detail - Review Comments Page 5 With: " in this EIS because it was not possible to identify a clearly " g) Page iv, global change Replace: " Cedar mouth " With: " Cedar River mouth 9) Page vi, paragraph 2, second sentence (and ginbal rhnncc) Replace: "Carko" With: "Carco" 10) Page vii, Table A. 1 his does not match Table 4 on page 79, Ave believe "Table A" to be the more recent version. Also, please clarify if this is with, or without, mitigation. "++" should be included in legend No nction impact to water quality should be "--" or "moderate negative impact'. No action impact to all anndromous species should be "•--" or "large negative impact". Transportation, Public Services and Public Ilenith/Safety should probably be "++" for all dredge niternalives and "+" for existing channel alternative. 11) Page 1, paragraph 3, firth sentence After "with numerous bank revetments or levees" Add: "which now cmtse the sediment to be transported down channel into the project reach." 12) Global change in document (one day may he important and this is the window that had been diseased) Change: "limited to June 15 - August 31" To: "limited to June 15 - September I" 13) Figure 1: Vicinity Map (and all maps using this base including Figure 2) Check the river network closely. There are several dead end drainages and networks that mny not he correct. 14) Figure 4 Why are no anadromoas fish shown above the confluence with on Rock Creek with no blockage shown? 1.5) Page 14, third paragraph, first sentence Replace: "(31,00 CY)" With: "(31,000 CY)•' 16) Page 14, third paragraph, third sentence Compare the levee/flocx1wn11 heights between the four alternatives. Minimum height of ranges may have a problem. Existing. Minimum, Mnderatc and Deep dredge alternatives minimum of ranges are shown as 0.59, 0.09, 1.36 and 0.63 respectively: hat all are listed as starting at Williams. Are these correct? A-7 Linda Smith, U.S. Corps of Engineers Cedar River 205 Project Draft Detail - Review Comments Page 6 17) Page 16,last paragraph, last sentence Replace: "that may not be suitable for resale, to the F.Ilnitt Bay PSDDA site." With: "to the F,Iloitt Bay PSDDA site or for sale." 18) Figure 6 The dredge tapers for the various alternatives are shown all endine at the same location. Please correct as required. It would also he helpful to show the location of the bridges, a grid, and eliminate the shading. 19) Page 26, first paragraph, sixth sentence After "This site" Insert: ", or an alternative." 20) Page 26.first ilarngraph,seventh sentence Replace: "because there arc areas of fine sediment that may have no resale value." With: "or harge it to another location." 21) Page 29, first paragraph, third sentence + Replace: "This province is primarily characterized by ...(through the end of the paragraph) extensively in the last century." With: "lite bedrock of the region is primarily igneous, although some sedimentary rocks are present. The age of the bedrock is primarily Eocene epoch (approximately 40 million years old) or younger. Some the sedimentary bedrock contains significant coal deposits which were mined in the last century, Glacial activity has been extensive in the region and most of the bedrock is boded under extensive layers of glacial till, glacial outwash and glaciolacustrian deposits. 22) Page 29,second paragraph, last sentence Replace: "formed" With: "shaped" 23) Page 30, first paragraph, first sentence Replace: "Black River and shallow Lakc Washington waters." Mill,: "slack River and bottom of Lake Washington." 24) Page 31, first paragraph, fifth sentence Replace: "most are prone to serious frequent flooding." With: "some are prone to serious frequent flooding.", or "many are prone to serious frequent flooding." 25) Page 31, third pnragrnph, fourth sentence Replace: "Seattle has claims a right " With: "Seattle claims a right Linda Smith, U.S. Corps of Engineers Cedar River 205 Project Draft Detail - Review Comments Page 7 26) Page 32, second paragraph, fifth sentence (and global change where it occurs) Replace: "MSI:' With: "(COI:)" At end of sentence add: "(COG = Army Corps of Engineers Jan I, 1919 vertical datum; COG - 6.82 NGVD'29)" 27) Page 33, paragraphs 4 & 5, page 34 paragraph I Is including Ren(on's outfall water quality germane to the EIS for this project? 2R) Page 38, Table 2 It may be helpful to normalize these nnmhers to redds per 100 feet. 29) Page 42, first paragraph, third sentence Are the food sources for Prickly Sculpin listed in order of percent diet? It may he helpful to list percentages or order significance. 30) Page 44, second and third paragraph See "General Comments" above for references to woody debris, logs, and other debris on the delta. 31) Page 46, first paragraph The Renton Airport's seaplane launching and docking area is located on the lake shore on the west side of the runway. The seaplane facility is a public use, transportation facility, which serves nearly 10,000 passengers annunlly. This facility is being impacted by the spreading of the delta to the west A recognition of this impact should he placed in this section. These impacts should be discussed in the review of impacts of delta growth, to the extent they are contributed from the project. 32) Pagr 46, fnurth, paragraph A recognition of any project impacts to the Renton Airport's seaplane launching and docking area should he placed in this section. The safety of passengers and aircraR should he addressed. 33) Page 53, second paragraph, second sentence Change: "August 31" To: "September I" Please make this a global change, it is ahout I % of the project time and a-e are alrenrly ppin` In he tight. 34) Page 5R, first paragraph Copy the last sentence from the first paragraph to the last sentence in the second paragraph. 35) Page 59, third paragraph. Inni sentence Strike: "slightly" to remain consistent. 36) Page 71, second paragraph, fifth sentence Please justify why the backwater may dramatically reduce overall abundance and diversity of invertebrates when this is largely blamed no frequency of dredging in the remainder of the document. A-9 RESPONSES: 16. This is an issue the City of Renton should pursue during the permitting process with the State of Washington. A-10 Linda Smith. U.S. Corps of Engineers Cedar River 205 Project Draft Detail - Review Comments page g 37) Page 72, last and page 73 third paragraph See "General Comments' no woody debris on the delta 38) Page 75,second paragraph Please include a mention of the expected project impact due to hard traffic on the light fluty asphalt roadway surfaces of the East Perimeter Road and in the park access road. 39) Page 77, first paragraph, second sentence Please add at the end of the sentence: "; the amount of floodwall will be limited to the minimum possible." 40) Page 79, Table 4 Please update to match the npdated Tahle A on page vii. 41) Fignre 15: proposed Haul Route for Dredge Material. Please revise the ronte from: N 6th St. - Garden Ave. N - nronsen Way N. To: N 6th It. - PIrk AYc_N - tlronsen Way N. 42) Page 84, third paragraph Add at end: "If t1m actual dredging frequency is significantly less than that anticipated for the 16 mitigation (once every three years), and the mitigation is determined to be significantly more than wns needed, future compensatory credit and relaxation of some requiremenL% will be investigated." Please call me at (425) 277-6205 if you have any questions. Thank you again for your efforts. Sineerely . � — 7 Ross f lathaway, Project Manager Surface Water Utility IIif )CS,97-4OT RnIf ps CC: lay C-ingmn. Ciry nrR,etnn. F.mcutive Ass;,,ant G"R Timmerman. City of Rentnn. Planning. nuildin[, N10 is Wnrks Admininamr Sam Chastain. City of Rentnn, Community Services Administra ro Ron Men. City of Rentnn, Illinly Synema Dh,ctnr Leslie nnlach, City of Rentnn, Parks hlehdi Nakhiiri, nminR Airplane Cnmpany Fliraheth Warman nneinR Airplane Cnmpany Gail Reed, City of Rentnn, AirT,," Ronald prak a. City of Renton, Surface Wirer :SF _--SEA. 17. Concur. However, floodplain gravel deposits are frequently protected by levees or other bank protection and have become vegetated and unavailable for river movement and deposition. City of Seattle Norman B. Rice. Mayor Seattle Public Utilities Diana Galc, Director May 9, 1997 Ms. Merri Martz Department of the Army Seattle District, Corps of Engineers Post Office Box 3755 Seattle WA 98124-2255 Dear Ms. Martz Thank you for the opportunity to review the Cedar River Section 205 Flood Damage Reduction Study Draft Environmental Impact Statement. Seattle Public Utilities (SPU) supports the "minimum dredge" preferred alternative presented in the Draft EiS. We believe that SPU and other appropriate jurisdiction have been kept informed of the Section 205 Flow Damage Reduction Study and offered sufficient opportunity for comment. We believe that, in general, the environmental impacts have been adequately addressed. Please note that we would like to offer the following suggestions for improving the Draft Ells. Page I, Section I.1 SPU staff conducted extensive steelhead spawning surveys during the spring of 1996 and again this spring. Surveyors have noted that most gravel bars currently present in the river channel show evidence of significant scouring and deposition. it is true that relatively few 17 gravel bars remain in the river, due largely to its confined nature and enhanced ability to transport sediments into a relatively few deposition zones, including the proposed project area. flowever, in contrast to your statement in the second paragraph of this section, our observations indicate the remaining gravel bars are quite barren of vegetation and likely to be remobilized during winter high water events. Dexter Horton Building, 1 Oth floor 710 Second Avenue, Senttle WA 98104 Tel: (206( 684-5851, TTY/TDD (206( 233.7241, FAX: (206( 68AA631 equolempkyyment opportunity, offirmative oction employer. Accommodations 6 people with disabilities providai on rrrlue•J A-11 RESPONSES: his. Merri Martz Seattle District Corps of Engineers 18. Editorial changes made to Figure 4. 19. This recommendation would not accomplish the project purpose of providing 100 year flood control in Renton. There are many opportunities for restoration of fish and wildlife habitat in the middle and upper Cedar River that would provide significant benefit; however, these issues are not directly relevant to the proposed flood control project. 20. The estimated maintenance dredge volumes are an average of predicted sediment accumulations in the project area during the life of the project. This takes into account the possibility of extremely large sediment accumulations which have not been observed in recent years. It is estimated that the actual maintenance dredge volume will be similar or less than the construction dredge volumes, but the calculated volume is shown as a maximum amount that may need dredging. Figure 4: There are several errors in this figure as listed below • The Landsburg diversion dam currently forms an impassable barrier to upstream migrating fish. 18 • Lower Cedar Falls at river mile 34.2, 1.5 miles below Masonry Dam, forms an impassable falls blocking upstream fish migration. • Masonry Dam at the west end of Masonry Pool forms an impassable dam. • The overflow dike separating Masonry Pool and Chester Morse Lake is a passable dam. Page 11. section 2.1.2 It is true that, during severe flooding, many levees are overtopped and water is stored in former flood plain areas behind these levees. However, during moderate floods, most levees function effectively to confine flows. Confined flows in these areas are more able to scour and transport sediments damaging incubating salmon and steelhead and perhaps 19 increasing the rate of sediment deposition in the proposed project area. We recognize that levee removal may only provide minor reductions in downstream water levels during future storm events. Nevertheless, this option could provide significant benefit for fisheries resources, help restore the natural structure and function of the river and reduce the rate of sediment deposition in the proposed project area. Page 15, section 2.2.3 Here and in subsequent descriptions of dredging alternatives, estimated initial dredge 20 volumes are less than subsequent maintenance dredge volumes. Please explain why this is the case. Page 26, section 2.2.7 see Is it reasonable to assume that, without dredging, a barge can be located close enough to 2 the Boeing property to allow an acceptable method of sediment rehandling? If dredging is required, will it be necessary to analyze the potential environmental impacts? 097-205.doc Page 2 May 9, 1997 A-12 0O S: M.S. Mari Mart. Seattle District, Corps or Engineers 21. No detailed studies have been conducted on this topic; however, visual observation of low flow conditions by Corps and other agency staff, and later fish migrations have indicated that adult salmon ascend the lower River with difficulty during the lowest flow time periods (late August). Additionally, the Washington Dept of Fish & Wildlife has further information on actual run timing for the past several decades. 22. Concur. See section 3.4. 23. The source of this information is Washington Department of Fish and Wildlife steelhead escapement figures. Sleelhead populations have remained steadily low since the early 1980s despite supplementation efforts. There are several reasons for this, including predation at the Hiram Chitienden Locks. 24. USGS Gauge No. 12119000 (Cedar River at Renton) is located at RM 1.6 (2.6 km), which is upstream of the proposed project by approximately 0.35 miles (.56 km). It is not anticipated that the project will affect this gauge. Page 36, section 3.3 We are not familiar with any studies or analyses to indicating that a barrier to adult salmon 21 migration may presently exist in the proposed project area or downstream delta. if you have information indicating that this is the case, please reference. Page 38, section 3.4 Removal of large woody debris is cited as a factor that has exacerbated scouring of smaller 22 substrates suitable for spawning. It is likely that levees and other sources of channel confinement are an equally important factor contributing to the scour of smaller substrates in the channel. Page 39, section 3.4 The third paragraph states that hatchery plants of steelhead up until the early 1990s were 23 unlikely to have bolstered steelhead populations. Please reference llte source of this information. Page 43, section 3.7 Although all salmonid species mentioned here are under various stages of review for listing under the federal Endangered Species Act, not all are formally considered "candidate" species. While it may not be necessary for the purpose of this document, the National Marine Fisheries Service should be able to provide a more precise definition for the listing status of each species. Page 47, section 3.14 No mention is made of the permanent impact to the USGS stream gauging station no. 121 19000 (Cedar River at Renton). This station is of regional importance as a long term 24 measuring point for Cedar River hydrology. Please explain what measures will be taken to maintain high quality streamllow measurements through the construction period and beyond, as the channel geometry will likely be unstable as a result of the dredging. 097-205.doe Page 3 May 9. 1997 A-13 RESPONSES: Ms. Merri Manz Seattle District, Corps of Engineers 25. The project was designed to minimize head cutting to the maximum extent practicable, by sloping the dredge profile up to zero dredge between Logan and Williams Avenues. Minor restabilization of the channel in the dredged area is expected to occur; however, this is expected to be negligible compared to the volume of sediment which will move through and deposit in the project reach from natural processes. 26. It is expected that dredging will entrain and kill significant numbers of prickly sculpin during construction and maintenance. It is unknown how quickly sculpin will recolonize an area after dredging, but invertebrate species typically completely recolonize a disturbed substrate after 10-12 months (Rees, 1959). Based on sampling conducted on sculpin in the lower Cedar River (Tabor, pers. comm.) we would expect prickly sculpin to completely recolonize the lower Cedar River in 1 to 2 years after dredging. If maintenance dredging occurs every 3 years, it would be anticipated that approximately 1 year out of 3 would have higher prickly sculpin populations than exists under current conditions, while 1 to 2 years out of 3 would have lower prickly sculpin populations. If maintenance dredging occurs less frequently than every 3 years, it would be likely that prickly sculpin populations would increase compared to the existing conditions. Hence, the Corps has assumed there will be an increase in predation on sockeye and chinook fry. Likely from the increased prickly sculpin population and possible increased trout populations. 27. Concur. The final EIS reflects a recognition of the likelihood of increased predation on chinook fry as well as sockeye fry. See sections 3.4.2 and 5. for additional information on impacts to chinook and proposed mitigation. 28. It is unclear if predation on coho juveniles will increase as a result of this project. Coho juveniles are significantly larger than sockeye or chinook fry. Coho juveniles are typically 120 mm or larger. Larger predators that may feed on coho juveniles do not appear to be present in significant numbers, nor are the populations expected to increase. It is not expected that coho will be adversely affected by the proposed project. However, coho do feed on sockeye and chinook fry and longfin smelt. Coho may have an increase in rearing area due to the lake backwater conditions during their transit through the lower river. Page 49. section 4.1 There is no mention of the potential environment effects of head cutting as the longitudinal 25 profile of the reestablishes itself after the dredging project is complete. Is this because the degree of head cutting is not expected to be significant? Page 54. section 4.3.1.1 Here an in the subsequent dredging options, the documents claims that prickly sculpting mortality during periodic maintenance dredging will be sufficient prevent an increase in the 26 population size. What evidence might be presented that periodic dredging will have a sufficient effect on the prickly sculpting to ensure that the population does not increase in response to the expanded habitat created by the dredging project? Page 57, section 4.3.2.4 No evidence is presented here to demonstrate that the increase in predator habitat will not 27 have a significant effect on outmigrating Chinook salmon, nor that Chinook salmon are less susceptible to predation than sockeye salmon. We are not aware of any information on the size, timing or condition of juvenile Chinook entering the project area. Page 59, section 4.3.3.3 Even though coho might be less susceptible than other juvenile salmonids, predation of 28 juvenile coho in the project area under all dredging scenarios is likely to increase. It seems unclear whether or not this increase will be significant. Thank you again for the opportunity to comment. Sincerely, -, i George 11. Schneider, P.E. Water Resource Manager 097-205 doc Page 4 May 9, 1997 A-14 ..--.,PC =S: 29. Concur. Additional information included in Sections 3.11 and 4.10. 30. Coordination is currently occurring between the Corps, the City of Renton, Boeing and King County to resolve construction scheduling. O King County tVn.le —f— Tr 1.t,enl DWIA.n ()rprt rn nr Nnn 1 Rr.m,rc 821 4rn u1 A,vnue 51e, %VA qn I1N-1 s9A May 8, 1997 Ms. Merri Martz Environmental Resources Section U.S. Army Corps of Engineers P.O. Box 3755 Seattle, WA 98124-2255 ATTN: Cedar River EIS CedacBkwLSe.rdion_20 B sd12amaae�ieduc =--Study-Dral.LUS Dear Ms. Martz: King County's Wastewater Treatment Division would like to submit the following comments regarding the Cedar River Flood Damage Reduction Study DEIS. haRSRotMtion Document should provide more detail on the existing transportation 29 system and identify potential adverse project effects upon the roadways and traffic circulation. What mitigation measures are anticipated? 30 Pslb1i.c_5= cesLUAiljSjes Note that King County owns and operates the Bryn Mawr Siphon and Trunk within the project corridor. See attached figure. • Submit construction drawings for the proposed project to the King County Wastewater Treatment Division for review during design development so King County facility staff can assess the project's impacts. For additional information contact Eric Davison of the Wastewater Treatment Division at 684-1707. • Contact Ed Cox of King County's Wastewater Treatment Division at 684-1292 a minimum of 72 hours prior to commencing construction in order to allow staff time to arrange having a King County inspector on site during construction. • King County has a permanent easement for the siphon and trunk sewer line within the proposed project corridor. Before this project is undertaken, King County must be assured the right to maintain and repair its facilities. In the event that facilities must be relocated, a new permanent easement must be provided. Contact Larry Ellington at 296-7816 regarding this matter. CLEAN WATER - A SOUND INVESTMENT A-15 Cedar River Flood Damage Reduction Study May 8, 1997 Page Two • King County intends to undertake improvements to the Bryn Mawr Siphon and Trunk. A third barrel to the existing siphon would be added, and the 27-inch diameter trunk line would be replaced with a 36-inch diameter pipe. Construction would occur in phases. Phase I begins in October 1997. Phase II begins in May 1998. Contact Rick Andrews, Bryn Mawr Project Manager at 684-1306 for more information. Mj.tjgation_and—Monitotiug-Lan A monitoring plan should be prepared prior to project permit application. Thank you for the opportunity to review and comment on this proposal. Sincerely, Tim Goon, Senior Environmental Planner King County Wastewater Treatment Division attachment cc: R. Andrews E. Cox E. Davison A-16 King Counla• U'alrr and I.nnd Resources Uh•islnn IM•Ivrrtmrni nl u.�n�ral Rranrrrra 'nrl l'Illh A, 4�flr'-`21M1 Crn nlr. lvA •Iarn.l (2rK.1 ?9n-FS 19 (2Dr) 296-01112 rAS Merri Martz Department of the Army Seattle District, Corps of Engineers Post Office Box 3755 Seattle, WA 98124-2255 Dear Ms. Martz: April 19. 19Q7 The Cedar River Council has reviewed the Crdar River ,Section 20.5 Florid Damage Reduction Study Draft Environmental Impact Statement for consistency with the recommendations in the Cedar River Basin and Nonpolnt Pollution Action Plan. We found the preferred alternative —the "minimum dredge" —to he consistent with the Basin Plan, and we support it. Please see our more detailed comments (enclosed) which we ask that you address as part of the Environmental Impact Statement review process. We appreciated having Linda Smith from the U.S. Army Corps of Engineers come brief its on the alternatives analyied in the Environmental Impact Statement and thank you for the opportunity to comment. Sincer , 1-1 Frank Ural cck TrrJ i I Randy Rogers Mainctem 1 Representative Alayne R. Blickle King Conservation District Jrf�Iner Mainctem 2 Reprcunadvp Eliza th Warman Boeing Company A✓ sleve Moddenmeyer S.atde Public Utilities Steve Linde Taylor Creek Representative Tim Schlitrer Councilmember, City of enton 10wQ 6 • ��Js_ David O. Fields Inc Creek Representative Donald Nettleton ttlleton Plum Creek Timber udith Fillip Mains a Rep la ive ` �`Pvh_ rps King Canty Councilmember A-17 Cedar River Section 205 Flood Damage Reduction Study Draft EIS Frank Urabeck, Jean White Summary of Preferred Alternative - "Minimum Dredge": An average of 4 feet of sediment would be dredged from the channel from the mouth of the Cedar River up to Logan Avenue and then sloping the dredged depth up to zero to meet the existing gradient at Williams Avenue. Levees and/or floodwalls would be placed along the right bank from Williams Avenue to the mouth and on the left bank from Williams Avenue 1000 feet upstream down to the mouth. Bank protection (rock) would be placed below ordinary high water on the left bank below Logan Avenue for approximately 400 linear feet The south Boeing bridge would be modified to be hydraulically jacked above the 100 year flood level during flood events and the levee openings at the bridge would be closed using rigid moveable structures. Mitigation would include: Native riparian vegetation would be planted along both banks of the Renton Reach. A grormdwatcr fed pool and side channel at an upstream floodplain location with groundwater near the surface (either Elliot levee site or lower Summerfield site) would be constructed to create salmon spawning, winter refuge and rearing habitat. Other alternatives evaluated in the Draft EIS: No Action; Existing Channel Depth with Levees and Modifications to the South Boeing Bridge; Moderate Dredging (6 foot) with Levees and Modifications to the South Boeing Bridge; and Deep Dredging with Levees and Modifications to the South Boeing Bridge. In reviewing this Draft EIS, we asked four questions: 1. Is the preferred option consistent with the Cedar River Basin Plan? Yes. The Basin Plan supports any flood damage reduction program in the Renton Reach that: • Establishes and maintains channel capacity at the 100-year discharge; • Minimizes the frequency at which channel maintenance must recur, and • Minimizes the area of aquatic habitat that is disrupted or otherwise impacted by sediment removal. 2. Was there adequate treatment of alternatives? Yes. 3. Was there adequate coordination %ith the appropriate jurisdictions/agencies and adequate opportunity for public comment? Answer yes on both points. 4. Was the environmental impact analysis adequately addressed? Yes. One question that might be raised during the EIS process is whether or not the 4 foot "minimal" dredge is preferable to the 6 foot "moderate" dredge. The 4 foot dredge is more consistent with the Cedar River Basin Plan's goal of minimizing the area of aquatic habitat that is disrupted or otherwise impacted by sediment removal. A-18 _3PMES. CMEN t a: 31. Flooding in the lower Cedar River first occurs on the left bank just upstream of the south Boeing bridge, even at flows as low as 2200 cis. During high flows (>6000 cfs), flooding occurs in several areas upstream of 1-405 as well as along both banks of the lower Cedar River. Floodfighting efforts consist primarily of sandbagging low spots and removing debris from bridges to reduce bridge damage. 32. The Masonry Dam is operated by the Seattle Water Department, primarily for water supply. See additional information in Section 2.1. 33. The benefit/cost ratios are added to Section 2.2. A detailed description of the Corps economic analysis is in the DPR, see comment 1. 34. Concur. See Section 2.2.6 for added information. 35. Additional investigation work is currently being conducted on the proposed mitigation site. See additional information in Section 5. 36 and 37 Editorial changes made as appropriate. Reference particular section. According to the Draft EiS, the 4 foot dredge alternative is expected to cause the loss of 2560-3840 square feet of poor and moderate quality adult salmon spawning area. A maximum of 235 redds have been observed in this area during the spawning season. The 6 foot dredge altemative would cause the loss of poor to good quality spawning habitat is estimated to be 4740-7100 square feet_ A maximum of 435 redds have been observed in this area - Frank Urabeck makes the following recommendations for improving the Draft EIS: 31 Expand the description of flood conditions to include when and where flooding first occurs and what flood fighting measures now occur during significant flood events. Should add a paragraph describing the operation of Masonry Dam, the Masonry Dam 32 Flood Study and what assumptions were made about how the results of the Masonry Dam Study will impact the flood protection provided by the dredging alternatives. 33 Should provide a benefit/cost analysis for each final alternative so readers can review the Corps of Engineer's decision process. . . Should describe the level of flood protection immediately after dredging and the trigger 34 for re -dredging. Should explain when the re -dredging decision will be made - i.e. will the decision be made in the spring, after winter flooding, so the channel can be re -dredged that summer and full 100 year flood protection is in place for next flood season? 35 Describe what hydrogeologic work has been done to show that a groundwater -fed habitat ch:umel will work on the site downstream of the Elliot project. p. 2, paragraph 13 - Recheck records on the ship canal history. The decision to reroute the Cedar River was made for land reclamation for the City of Renton, although the 36 digging of the ship canal may have been anticipated. it was fortuitous that the Cedar River was rerouted, allowing enough water for the navigation of the Ballard Locks. 37 Figure 6 - Label Logan St and Williams St bridges on Channel Distance axis; the distance from the mouth of the Cedar on figure 6 doesn't correlate with the stationing on Figure 7, sheets 1-5; should show water surface profile at maximum and minimum Lake Washington levels, io readers can better understand the context - Figure 7 (Sheets 1-5) - Should show dredging limits. Add figure showing typical cross- section before and after dredging. p. 50, paragraph 4.13 - Add more explanation of what will trigger re -dredging or maintenance dredging - i.e. will re -dredging be triggered when channel is filled to A- B current condition? Recommend that re -dredging be triggered when less than 50 year flood protection exists. p. 54, paragraph 4.1.3-3 - Add figure showing a typical cross-section of the existing channel under current conditions and the channel conditions when maintenance dredging would be triggered. This alternative should be compared to the no action alternative. Should to an improvement to sockeye and other fish over no action alternative. p. 79, table 4 - Evaluation should have been against the no action alternative, this is the existing condition. p. 81, paragraph 5.1 - What happened to the existing delta dredging issue? The City of see Renton and Boeing have been concerned about birds gathering on the delta, 2 threatening the safe operation of the airport. Has this issue gone away? Sediment buildup on the delta will continue to occur from fine sill deposition. p. 83, paragraph 5.5 - Add the Elliot levee and Summerficld sites to Figure 17 and make reference to them here in the text. Figure 17 - Show location of side -channel (figure only shows property where side channel might be considered). Figure 18 - Show existing Elliot side -channel on map or better label it; label how far it is from the proposed mitigation channel and show the cross-section of the mitigation channel. A-20 LAI(E WA5HINGT0N/CEDAR RIVER WATERSHED F 0 R U h Co-chair, Chuck Mosher, Bellevue City Council Co-chair, Margaret Pageler, Seattle City Council Coordinator, John Lombard 700 Sth Avenue, Suite 2200 Seattle, Washington 99104 206 296.8051 206 I96 0192 fax Participating May 9, 1997 Judsdlcttom: n.ts. e„4ryr• Reaux Am Ms. Merri Martz Bellevue Environmental Resources Section U.S. Army Corps of Engineers Bothell Post Office Box 3755 Seattle, Washington 98124-3755 t lyde Hill RE: Suppg![Lfq PreferrgdAtermitive in Cedar River DEI.$ Hums Point Dear Ms. Martz: Kent We are elected officials from local governments participating in the Lake Washington/ Cedar River Watershed Forum. We are writing in support of the preferred alternative for King County the Cedar River Section 205 Flood Control Project ("Minimum Dredging Combined with Levees and Modifications to the South Boeing Bridge"), as described in the project's Draft Khkland Environmental Impact Statement (DEIS) and its Draft Detailed Project Report. I Ake forest Park This alternative is not only the least expensive means of providing protection against a 100- Year flood on the final mile of the Cedar River, it can also be argued for on environmental Medina grounds, since it makes some ecological improvements to the lower river and provides mitigation for the minor, unavoidable impacts that are anticipated, it provides a good Mercerlsland balance between the depth ofdredging and the height of new or raised levees and floodwalls, and it does not create an undue burden on the operation of Boeing's 737/757 Nreecaslle plant at the mouth of the Cedar River. u.dmand We would request, however, that the Final Environmental Impact Statement discuss the See 27 potential impacts of this alternative on Chinook salmon in more detail, in light of the Benton potential listing of Puget Sound Chinook under the Endangered Species Act. e Last July, many of us wrote to the stRte's congressional delegation in support of line -item funding in the FY 1997 budget for the federal share of this project, recognizing its importance to the Lake Washington ecosystem and to the regional economy, because of Shnrellnr �'. i the location of Bocing's plant. Though the preferred alternative is the least expensive Wnndlnrllle Yarrow Point take Wathingten/Cedar River Watershed rerun Micron To Rrrelnp and coordinate regional actions by local 9err,"wels in: pretest and rnhanre the wramdinary salmon and bout pnpulatiem of the take Washin910n watrrMrA; protect Ike extraordinary water quality or the lake; and Reduce regionally significant nnnd damage on the cedar M• A-21 Ms. Merri Martz May 9, 1997 Page Two action identified in the DEIS. at an estimated $7.9 million it is still more than S3 million more expensive than the estimate from the Corps' original reconnaissance report, which was used as the basis for the FY97 federal line -item appropriation. The project may, therefore, require a further appropriation in the FY98 federal budget to ensure construction remains on schedule for summer 1999. The Corps has estimated the cost for maintenance dredging at S2A million, which in the "worst case" could be incurred as often as every three years (assuming heavy, frequent sedimentation from high river flows). The federal government would not be responsible for this cost; under federal law, maintenance costs would be entirely the responsibility of the City of Renton, which must already pay at least 35% of the construction cost of the project. This is a very heavy burden for one suburban city. Renton has asked the region to consider sharing maintenance costs for the project out of new regional funding that may be developed to address major river flooding hazards. We agree that this project would be worthy of serious consideration for any such funding -- though the mechanism, contributing entities and project criteria for such possible funding are all unclear at this time. The low -gradient, artificial river channel that was built early in the century by a private waterway district, redirecting the Cedar River into Lake Washington, cannot transport the river's natural load of sediment. Without dredging, the Cedar would eventually spill onto the runway of the Renton Municipal Airport, blocking salmon passage, harming the lake's water quality, closing the airport (the sixth busiest in the state and used by Boeing to deliver airplanes to its customers) and probably forcing the closure of the Boeing plant, whose annual production of airplanes is worth approximately S 14 billion. This obviously would be unacceptable not just to Renton, but to the entire region. The region may have an interest in using the clean gravel and sediments from project dredging to help cap some of the areas in the Lake Washington system with polluted sediment, such as the shores off of Gasworks Park or some of the historic outfalls of combiner) sewer overflow facilities. We intend to explore these possibilities with the City of Renton. A-22 Ms. Merri Martz May 9, 1997 Page Three Thank you for the opportunity to comment on the Cedar River Flood Control DE.IS. If you have questions about our comments, please do not hesitate to contact us through John Lombard, Watershed Coordinator for the Lake Washington/Cedar River Watershed, at 296-8051. Sincerely, Chuck Mosher Councilmember, City of Bellevue Forum Co -Chair Larry Philtfps Metropolitan King County Councilmember IS C'eaVe rse le a e Mayor, Town of Ilunts Point Pat Hawkins i Councilmember, Town of Clyde [fill Diana Gale r Margaret gelcPcr Councilmember, City of Seattle Fontm Co -Chair Maggi Fimia l Metropolitan King County Councilmember Linda 41aman Deputy Mayor, City of Mercer Island Stua�� Councilmember, City of Newcastle cc: Colonel Donald Wynn, District Engineer, U.S. Army Corps of Engineers Mayor Jesse Tanner, City of Renton Elizabeth Warman, Manager, Local Government Affairs, The Boeing Company A-23 INDIII�? MUCKLESHOOT INDIAN TRIBE TRIBE FISIIERIF.S DEPARTMENT May 11, 1997 Merri Martz Department of the Army Seattle District, Corps of Engineers Post Office Box C-3755 Seattle, Washington 98124-2255 RF.: Cedar River 205 Flood Control Feasibility Study: DELS Dear Ms. Martz, ��Mf3 TRIBE I and my colleagues at the Muckleshoot Indian Tribe appreciate the opportunity to review the draft F.IS for the Cedar River 205 Project. This project has the potential to impact the ecological stability of both Lake Washington and the Cedar River, and the salmon runs that depend on them. The DEIS is well written and comprehensive. Although the Tribe disagrees on some points, we are confident that these points can be adequately addressed in a scientific manner in the Final Environmental impact Statement (FEISJ Our main points are presented below. More technical comments on the Draft FIS are included as an appendix to this letter. We support the preferred alternative of a minimum dredge, but only under duress. The Cedar River reach in question is artificial, should arguably never have been built, was poorly designed over an inadequate gradient and has to be repeatedly dredged. Dredging impacts the fish runs that have managed to utilize this reach. But because of development constraints, the river can never again be allowed to come to its own equilibrium state; it must be. constantly re -engineered. 39015 172nd A—o ,,q S F. • Auhum, Washington 90092 • (206) 931-0652 • FAX (206) 931-0752 A-24 .=SIMSE_. 1 ,:,.y IJ 34 t i -- COMMENTS: 38. Mitigation is appropriate to the current level of spawning which occurs in the project reach. However, it could be an important benefit to replace lost upstream gravels. The Corps encourages the Muckleshoot Tribe and other interested parties to pursue using some of the dredged material for habitat enhancement purposes. The DEIS does not to smelt, sockeye, a d ch nooknsalmon. sufficient The F nala,ElS should include discul on the potential ssion of the following points% alztelt Most of the smelt in the Lake Washington Basin spawn in the study reach. These fish are the predominant pelagic fish in the lake and serve as the prey base for squawfish, cutthroat trout, rainbow trout, largemouth bass, smallmouth bus, Prickly sculpins and other fish predators. The potential smelt impacts (and benefits) presented are largely theoretical. If smelt are impacted by this project, sockeye will become the main pelagic prey item and the sockeye run could be decimated. Dredging the bed of the Cedar River four feet deeper than it is presently is still within the range of river conditions that we know historically supported smelt spawning. A six foot dredge or deeper is beyond the bounds of the historical smelt data. It should be noted that there is currently no reliable way to mitigate for smelt. So little is known about smelt spawning behavior and requirements that engineered spawning habitat cannot guarantee fish use. Smelt cannot be artificially propagated. If the smelt spawning area is eliminated there is no way to replace these fish. Consideration of smelt impacts should therefore be very seriously considered. Seckm The sockeye spawning concentrations appear to be moving downstream over time, coincident perhaps with the movement of bedlnad. Although a relatively small 38 percent of sockeye spawn in the study reach now, the future percentage will increase.. Mitigation for dredging should include restoring gravel to the upper anadromous reaches of the Cedar. Since much of the dredge spoils will be high quality gravel originating from upstream, putting the gravel back will be excellent mitigation. We would be happy to discuss placement of these gravels in more depth. Chinook Chinook salmon are expected to be added to the Endangered Species list, with the listing process starting in December. In 1993 only 156 naturally spawning Chinook rehirned to the Cedar River. In 1995 an estimated 18,000 smolts survived to pass the fry trap in the lower river on their way out to sea. The unique genetic identity of Cedar River Chinook, coupled with the low survival seen in past years make this species very susceptible to dredge impacts. Deeper water will be more likely to harbor predators on Chinook and sockeye. The US Fish and Wildlife reports show that prickly sculpins are the most numerous predator on sockeye fry in the study reach, and cutthroat have the highest A-25 RESPONSES: COMMENTS: 39. Predator studies, conducted to date, have estimated consumption rates of prickly sculpin at 2,457 fry per hatchery release during low flows (<13 m3/s, 467 cfs). (Tabor & Chan, 1996b) It has been observed the predation rates are higher during hatchery releases when there are large numbers of fish moving through the lower river in a short period of time. During higher flows and for naturally produced fish, the predation rate would be much lower. So, the actual expected loss of sockeye fry due to increased predation is not precisely known. See Section 5 for proposed mitigation and reasoning. 40. The Corps agrees that plantings on the delta would likely provide a safe transportation or resting area for sockeye and Chinook fry entering Lake Washington. However, due to numerous concerns including: 1) the plantings may cause additional debris blockages and may increase flood surface elevations; 2) the concern that delta planting has only a minimal chance of success due to the high sedimentation rate; and. 3) the unknown changes that might occur in bird distributions, the Corps has determined that the proposed mitigation will adequately compensate for adverse impacts to sockeye and chinook fry from the likely increased predation in the lower river. consumption rate. At present these fish are clustered in the deeper, backwatered part of the channel where average velocities are lowest. Dredging will increase this type of habitat an estimated 5.8 acres for even the minimum dredge. Rickard, in his thesis on prickly sculpin calculated an average of 2.5 fish per square meter for the 2 e lake (Univ. of Wash Masters thesis, 1980). A backwater increase of 5.8 acres would, under the same densities, result in approximately 60,000 more prickly sculpins in this confined area, with more sculpin likely to come in from the lake opportunistically. If even a fraction of these sculpin consumed sockeye or Chinook fry, impacts could be substantial. It should be noted that sculpin above a certain size transition from eating small sockeye fry to eating larger fish such as smelt. Chinook fry are a transition -sized fish. Both the elimination of spawning habitat and the increased predation due to dredging are assumed to be mitigated for by the creation of a small spawning 39 channel near the Elliott levee. This 'trade' needs to be documented in greater detail. The FF,IS should include estimates of fry produced by this channel compared to fry lost to additional predators in the backwater area. For chinook especially there is a net loss since chinook are mainstem spawners and would not utilize a slough. Additional mitigation should include planting the delta to decrease predation on fry entering the lake. Currently the lights from industrial Renton allow birds and fish 40 to forage on fry throughout the night. By extending the river through this delta and creating cover, the impacts of these lights may be decreased, thus saving some fish. The vegetation will have the added benefit of keeping flat-footed birds (ducks, geese, gulls) from landing on the delta and creating an aircraft hazard. Thank you. If you have any questions or need any assistance please contact me at 931-0652, ext. 125 or Karen Walter at ext. 116. Sincerely F.ric Warner Fisheries Mitigation Specialist A-26 rsr:SP_..jES: 41. Concur. Seepage iii. 42. The City of Renton can obtain federal flood insurance from the Federal Emergency Management Agency if flood protection is at or exceeding 100 year protection. During economic analysis, conducted as part of the feasibility study, it was determined that the greatest federal interest was in providing greater than 100 year protection, even up to 200 year protection. However, the local sponsor indicated that 100 year protection would be their preferred level of protection. Approximately 50 year protection could be most cost effectively achieved by dredging, without the addition of levees. This is what the City did in the past. 43. The costs of each alternative have been updated, see p. iv and section 2. The existing channel alternative would require additional levees up to 1-405 and extensive modifications to all of the bridges in downtown Renton in order to avoid induced flooding upstream of the project area. 44. The summary table does distinguish between impacts that will generally occur over the long-term as a result of the different alternatives and then a special column for short-term impacts from construction and maintenance dredging. The summary table has been relabeled to provide more clarification. 45. Partially concur. The impacts of both habitat loss and likely increased predation on sockeye and chinook fry have been evaluated and used in the design of the proposed mitigation. The summary table necessarily provides a summary without the detail of information provided in section 4.3. Water velocities were measured during the time period that smelt eggs were being deposited and during the incubation period. Lake backwater effects, while not as significant during the winter and early spring, nevertheless will increase with the proposed project. APPENDIX. Additional Comments Ext<ct dim_Summagc page iii, paragraph 1 - It seems unlikely that pollutants from the Renton Airport and Boeing facilities 41 enter the Cedar River and Lake Washington only during Flood events since these facilities were built before the 1990 storm water requirements. It would be more accurate to state that there could be an increase in and more frequent loading of pollutants if the Cedar River is allowed to continue to fill its channel and flood into these areas. Page iii, paragraph 2- Alternatives The DEIS does not justify why the 100 year event is the chosen flood control event. 42 The FE1S should make this justification and evaluate why a smaller event was not considered as an alternative, such as the 50 year event. A smaller design event would likely result in a smaller impacted area, thus reduced project impacts. page iv, paragraphs 1 and 2 - It is unclear as to why the minimum dredge will be less expensive than the existing 43 channel alternative, especially if the minimum dredge will be removing more material at each maintenance cycle (171,000 cubic yards compared to 114,000 cubic yards). page vi, paragraph 2 Sockeye, chinook, and coho salmon and steelhead trout in the Cedar are an international resource that has major regional and local value. The FEIS should be updated accordingly. Table A, page vii a. The summary table should be modified in the FEiS to distinguish between short and long term impacts. For example, in general, dredging the channel will cause at 4,1 4 least short term increases in water turbidity which may adversely affect water quality, salmonids, and salmonid habitat. Therefore, it is doubtful that the existing channel dredging alternative will have no change or negligible change in the short term. b. The conclusions regarding impacts to the affected species of salmonids in the summary table are not substantiated. For example, the table does not reflect that there will be a loss of existing salmonid habitat through channel simplification and 45 that predator species such as prickly sculpin will likely benefit from the Increased backwater habitat created as part of the dredge. Thus, salmonids will experience at least two impacts; one from a loss of habitat, the other from a likely increase in predation. In particular, we disagree with the impacts (or benefits) attributed to chinook and smelt; these are theoretical and arbitrary at best. Chinook are likely to A-27 RESPONSES: COMMENTS: 46. Concur. See sections 3.8 and 4.7. 47. See #44 above. 48. Other than the 400 linear feet of riprap on the left bank immediately below Logan Avenue, no new protective material will be placed on the banks. Plants will be placed along the banks as described in section 5. Surveys, conducted in several years since 1986, have indicated that the channel cross-section Is significantly altered from year to year. The trapezoidal dredging prism will not last beyond the first winter after dredging. It cannot be predicted where bank scour pools will develop, but it is likely one or more such scour areas will be produced during the first winter after dredging. Moderate flows from 2000-3000 cis appear to deposit the most material while higher flows tend to cause scouring of the river channel. 49. The site of the proposed groundwater fed channel is located in approximately the 10 year floodplain, or slightly higher. This area would start being inundated by overflow from the main channel at flows greater than 6300 cis. The site is heavily vegetated and will be protected by large woody debris. The proposed mitigation will be designed to function as a moderate velocity habitat area during flows less than 10,000 cis. 50. See section 2.2.1 for percentage of river bank protected. 51. The original permit that allowed the diversion of the Cedar River into Lake Washington and the dredging of the channel permitted the dredging to a depth of 8 feet below the former Lake Washington low level (approximately 9 feet higher than current level). When the Locks lowered Lake Washington, all future maintenance of the channel permitted varying dredge depths from 8-12 feet below the current low lake level. 52. Editorial changes have been made as appropriate. have increased predation as well as the loss of some spawning and rearing habitat. The benefits ascribed to smelt are largely the result of smelt studies that failed to test sufficient water velocities, coupled with backwater effects that do not occur until later in the season when the smelt are gone. The summary of impacts identified in this table are also not consistent with the statements made on page viii, paragraph 2. c. The DEIS does not contain enough information to support the conclusion that there will be positive impacts to aquatic and riparian vegetation. The FETS should 46 have a table that documents the existing vegetation conditions including species, size, and proximity to the Cedar River compared to the proposed vegetation mitigation, also including species, size, and proximity to the River. 47 In conclusion, this summary table should be modified by separating out short and long term impacts (including the long term effect of perpetual maintenance dredging) as well as synergistic impacts that will occur as a result of the project. page viii, paragraph 3- The DEIS does not contain any data or analysis to support the last statement in this 48 paragraph. The FEIS should be updated accordingly by documenting the flood event necessary to create such habitat, the likelihood of such an event occurring, and the potential for the river to move the material including any new material introduced to floodproof the banks. page ix, paragraph 2- 49 The FEIS should indicated the sire of the flood event that would render the side channel proposed as mitigation unusable as a moderate velocity habitat area. page 1, paragraph 3- 50 The HIS should document how much of the existing Cedar River is affected by revetments and levees in Linear feet for each bank. page 2, paragraph 2. It is unclear from the description whether the original dredge 51 permit allowed the Cedar to be dredged 8 feet below present low lake level or historic low take level. The implication is that when the lake was dropped 8 feet this would affect water depth in the river reach in question. Figure 1: Vicinity Map The map is incorrect. The City of Kent should be mapped in almost a straight line between Renton and Auburn. The Kent watershed is shown within the Cedar 52 River watershed. Figure 2: Cedar River Basin Map This figure is misleading since most lower river tributaries are not labeled. For example, the Cedar has two Rock Creeks, but only the lesser known of the two is labeled. Landsburg dam is shown as passable which it is not. There are many A-28 --=5" -•.SEA. COMMENTS: 53. There is currently no information on the exact (or approximate) volumes of sediment from any of the upstream sources. King County studied the issue in the Current and Future Conditions report (1993). The Corps has assumed that efforts to control sediment as recommended in the Cedar River Basin Plan will only have a beneficial impact on the federal project. If the dredging frequency is extended beyond 3 years, the environmental and financial impacts will be much less significant. 54. There has been no quantification of floodplain storage area in the upper portion of the Cedar River. However, there are no levees in the middle and upper reaches that provide 100 year protection. In all flows greater than 20 years (7900 cis), significant portions of the upper and middle river floodplain already stores water. The removal of these levees would not provide an increase in storage volume. 55. See section 2.2. As described, all action alternatives will require a combination of levees and floodwalls along both banks of the river from RM 1.25 (2 km) down to the mouth of the river (a low berm will extend for the lowest 3000 feet on the left bank). 56. Noted. 57. Gravel recruitment is a function of erosion of the unprotected banks and movement of materials from the floodplain. There is little information on this subject: King County (1993) has the most comprehensive information available. This issue is peripheral to the EIS. 58. Noted. impassable culverts which are not shown; the WDFW database upon which this map is based is incomplete. page 11, paragraph 5- The plan referred to in this document is actually the Cedar River Basin Clan. A Master Clan is generally a term used for a large scale development. page 11, paragraph 5- The DF.IS analysis regarding the potential upstream sediment control alternative is 53 incomplete. The FEiS should evaluate the impact of upstream sediment control both as a potential significant adverse impact that may result in more frequent dredging and as a potential avoidance action that causes less frequent dredging. page 11, paragraph 6- The DEIS analysis regarding upstream levee removal and compensatory flood storage alternative is incomplete. The FEIS should qyn� the amount of flood 54 storage that would be available if the Cedar River floodplain upstream of Renton was restored and compare this value to the amount of storage that is needed to contain the 100 year flood in Renton. page 15, paragraphs 2,3, and page 16, paragraph I- 55 The EMS should indicate the potential length of the proposed levees and noodwalls that are associated with all of the alternatives. page 36, table - The table is attributed to me but is several years old and has since been updated. Non-native status should be attributed to Atlantic salmon and brown bullhead. Stickleback are abundant but variable. Smelt are increasing only in the even year class. 56 page 37, paragraph 2- it should be noted that the sockeye escapement numbers are based on index locks counts and not spawning ground counts. page 38, paragraph 2- Gravel movement is one way that a river could become "starved". The potential for 57 gravel recruitment should also be considered. The FEiS should also document the potential gravel recruitment. pages 38 bottom, 39 top - The M% S should include the data sources/literature to support the statements in 58 this section. Predators in the Renton reach of the Cedar are present more in riprap than they are in pool habitat and near woody debris. page 39, paragraphs 2, 3- A-29 RESPONSES: COMMENTS: 59. Noted. See section 3. 60. There is little to rely on in the literature concerning cutthroat trout populations. Tabor & Chan (1996a) admit the limitations of the estimate quoted in the DEIS, however it is expected that the lower Cedar River population is quite small. It is likely that there is a reasonable amount of movement of cutthroat between the lake and the lower river. However, there is little to no evidence to suggest that cutthroat are significantly reducing sockeye fry populations as they transit through the lower river. 61. The DEIS did not intend state that all rainbow trout in southern Lake Washington are hatchery trout. Further information has been added to section 3.4.1 to clarify the intent of the document. 62. See section 3.9 for added information. 63. This section evaluates the impacts to geology/sediments/soils/floodplains from the existing channel alternative. The existing channel alternative will maintain the channel bottom at approximately the existing level. Even if more material is dredged during maintenance, the channel bottom and sediments will remain approximately in their current condition with similar water velocities. The FEIS should replace the word "wild" throughout this page with the word "natural". The Lake Washington watershed is essentially a mixed system with hatchery fish outplanted in areas where natural spawning occurs, thus there is likely hatchery produced fish that return to the hatchery to spawn or spawn naturally in the Cedar River and its tributaries. The Chinook escapement goal for the Cedar is 1200 fish (based on live counts) which extrapolates to 2300 fish total. Are the other 59 numbers based on the index or the absolute? The FEIS should also have a section on hatchery fish since they too may be adversely affected by the various dredging alternatives. page 39, paragraph 4- The Muckleshoot Indian Tribe and the Suquamish Indian Tribe are also planning partners in the steelhead broodstock program. page 40, paragraph 1- There is evidence that suggests that cutthroat trout are also replacing the niche formerly utilized by coho in several tributaries within Lake Washington. The FEIS 60 should be updated. The population estimate given for cutthroat is not true. A mark recapture study of some Lake Washington cutthroat shows that they can traverse the length of Lake Washington in several days. Later studies show large numbers of cutthroat in the south end. page 40, paragraph 2- The rainbow trout found in the south end of the lake are not all hatchery fish as 61 stated. The hatchery fish are very distinct and of a uniform size. Almost all of the larger rainbows caught appear to be natural. The population size stated is too small. Lake resident rainbows have different diets than the stream residents discussed. page 45, paragraph 2- The section on the Duwamish Indians is misleading. While the Duwamish Indians were signatories to the Treaty of Point Elliott, it is the Muckleshoot Tribe that is the 62 recognized as the living descendants of the treaty signers. The Muckleshoot Indian Tribe is the tribe that is granted the right to continue to take fish at usual and accustomed fishing grounds in the fake Washington watershed. page 49, paragraph 4- It is unclear as to how the maintenance dredging impacts will be virtually identical 63 to the initial construction impacts if more material is removed during the maintenance dredging than the initial dredging (114000 cubic yards versus 31,000 cubic yards). page 51, paragraph 3- A-30 RE.,, .,NS��. COMMENTS: 64. See section 4.2 for further clarification. 65. Refer to section 3.2 which describes the existing water quality conditions. 66. The intent of this section is to indicate that the fish window is one method for minimizing adverse effects on anadromous fish, not that there is no impact. 67. This section states that sockeye fry survival is likely to be reduced due to the increase of predator habitat. Coho and steelhead juveniles currently feed for short periods of time in the lower Cedar River while transiting out into the lake. Riprap may provide some backwater habitat upstream of the lake backwater area which coho and steelhead juveniles could use for brief feeding periods. The riprap will not be replacing riparian vegetation other than blackberries. 68. Coho juveniles currently feed for short periods of time in the lower Cedar River while transiting out into the lake. They appear to feed primarily on sockeye fry, smelt eggs, other small fish and insects (Tabor & Chan, 1996a, 1996b). Coho feeding could be enhanced by the increase in lake backwater area as well as the riparian plantings which would increase insect and nutrient input to the lower river. 69. The lake backwater effect is less significant during winter and early spring, however it will still extend beyond the current condition. The lake level is raised starting in late February, during the smelt run. 6 4 The DEIS does not consider the potential adverse turbidity impacts that may occur as a result of storm events occurring when the front-end loader is dredging the river bottom. page 52, paragraphs 2,3,4- 65 The FEIS should document the existing water quality in the affected reach to support the statements in the water quality section. page 53, paragraph 2- Although there is a Washington Dept. of Fisheries and Wildlife fish window 66 adequate for accomplishing this work, it should be noted that this does not imply no impact. The Cedar River sockeye have one of the most extended spawning periods on record. In 1996 fish had already spawned at the headworks 20 miles upstream of the mouth by August 23rd. And some steelhead kelts may not leave the river until June or even July. page 54, paragraphs 1 and 2; page 55, paragraph 3- It is unclear the basis for the statements made in this paragraph regarding riprap creating habitat for rearing juvenile salmon upstream of 2000 feet. The FEIS should compare the existing habitat conditions compared to the proposed riprap conditions. 67 The dismissal of effects of increased predator habitat because of bulkheads presently on site ignores the backwater effect. Dredging may not remove prickly sculpins for very long because of quick recruitment from the lake. If the existing habitat conditions include overgrown levees or vegetation banks that could become functional riparian habitat, then the riprap will be displacing this habitat and cause an adverse impact. See also page 71, paragraph 4 where the DEIS clearly documents that large cottonwood trees will be replaced with smaller shrubby willows or smaller trees. page 57, paragraph 2- see The statement that chinook fry are not as susceptible as sockeye is undocumented. 27 Chinook fry are larger, but may rear in the area, thus increasing their predation risk. page 59, paragraph I - It It is unclear as to how the Army Corps determined that coho rearing habitat may be increased as a result of the minimal dredge alternative page 63, paragraph 3- 69 The backwater effect which supposedly helps smelt occurs after the smelt have spawned and died. page 65, paragraph 2- We Juvenile coho could also be adversely affected by the actual construction and 28 maintenance dredging if they are rearing in the project reach. A-31 RESPONSES: COMMENTS: 70. While the proposed mitigation addresses invertebrate populations specifically, it was with regard to their importance to the overall river food web (including salmon) that the impact was considered significant. The riparian plantings are specifically planned to compensate for the likely decline in invertebrate diversity and abundance by providing an increased source of nutrients as well as insects for an alternate prey base. 71. See section 3.8 and 4.7 for additional information. 72. The avoidance, minimization, rectification and mitigation for identified adverse impacts will adequately compensate for any adverse impacts. While it is true that every change, other than restoration, will likely incrementally add to the cumulative impacts in an area; this project will reduce existing adverse environmental impacts, such as pollution from Boeing and Renton during flooding. It is not expected that this project will contribute a significant adverse cumulative impact. 73. It is true that juvenile anadromous fish do not significantly utilize the project area. However, during flooding, it is likely that fish are washed downstream from areas upstream of the project. This project will reduce the chance of either adult or juvenile fish stranding on the airport and park. 74. It is true that sockeye clean the gravel during spawning. However, this reach of the river still accumulates fine materials and larger sediments during the incubation period of sockeye. It is not documented what the survival rate of sockeye eggs to fry is for the various reaches of the river. The lower river appears to be disproportionately affected by sediment movement and accumulation due to the unnatural gradient. 75. Additional information is provided in section 3.8, 4.7 and S. The contingency plan will be worked out in detail during Renton's permitting process with the state agencies. page 70, paragraph 2- 70 The DEIS fails to consider the potential adverse impacts to salmonids that may occur as a results of invertebrate populations. page 71, paragraph 4- The FEIS should document the number, size, species, and location of existing riparian vegetation, document the number, size, species, and location of vegetation that is proposed for removal, and the number, size, species, and location of vegetation to be replaced as mitigation. 71 page 73, paragraph 5- The DEIS does not clearly document the information to support the statement that the riparian zone will be more extensive after construction than it currently is. page 78, paragraph 4- It is unclear as to how the Army Corps could conclude that all dredging alternatives 72 will not add a significant adverse impact above and beyond the cumulative impacts that exist when maintenance dredging is proposed to occur every three years in perpetuity. Also the statement regarding the reduction of fish stranding as a result of the project assumes that anadromous fish are using the lower section of the Cedar River during flood events. The FEIS should produce some data/literature to support this 73 statement. The statement may only apply to adult spawning salmonids in the project reach. It could be argued that juvenile anadromous are not likely to be within the project reach because there is little if any reduced velocity habitat available in this area. page 81, paragraph 4- see The statements regarding the rectification of adverse impacts to riparian vegetation 71 are unsubstantiated without documentation to support that riparian functions will be increased post construction compared to the existing riparian vegetation - page 82, paragraph 2- The designation of the spawning habitat as poor to moderate is undocumented. 74 True, this area becomes impacted with fines, but if the sockeye spawn in the numbers attributed to this area, the Fish themselves clean the gravel. page 83, paragraph 2- The FEIS should document the spacing and size of vegetation that will occur as 75 mitigation as well as the proposed contingency plan in the event that the vegetation does not survive. F.=FJ ..ES.-.JSE... 76. Concur. This issue is addressed in somewhat more detail in sections 4.5, 4.7 and 5. 6 0 United States Animal and Animal Damage 720 O'Leary St.. NW g� Oapartment of Plant Health Control Olvmpia. WA 98502 Agriculture Inspection Service May 9. 1997 Merri Martz Environmental Resmirces Section U.S. Army Corps of Engineers P.O. Box 3755 Seattle, WA 99124-2255 Dcar Mary, Our agency (ITS. Department of Agriculture, Animal Damage Control) has had an opportunity to review a copy of the dean Environmental Impact Statement (EIS) for the Cedar River Section 205 Flood Damage Reduction Shady. While we understand the importance and need of the project ss it relates to the preventinn of future flooding, we do have snme comments that we feel should be addressed. Most of our initial concerns were allayed following discussinn at the public workshop in Renton on 19 April 1997. Our concern regarding the environmental impacts of the Cedar River Project is that it could cause an increase in bird strike hazards on the adjacent airfield. Our interest in this issue stems from our agency's role in allevinting bird hazards at airports nationwide. Bird strtkes are a concern because they cost the United States air traffic industry millions of dollars annually in repair expenses and lost revenue, and they sometimes result in human fatalities (eg. An aircraft crashed after colliding with Canada geese at F.Imnnderf Air Force Base, Alaska in Seplemher 1995, killing all 24 passengers). Our agency has a Memorandum of Understanding with the Federal Aviation Authority, (FAA) "...to provide technical and operational assistance needed to reduce wildlife hazards to aviation on and near airports". It has been our experience that preventing bird -strike hazards in the early stages of new project development through proper planning greatly simplifies bird hazard reduction in subsequent years. It ix our understanding that the Cedar River project will restdt in uthoontial landscape and vegetative renovations along the lower mile of the river to enhance the aesthetics for the park and to provide refugia for spawning fish. These are worthwhile objectives, but we suggest that prior to initiation, ail revegetatinn projects he given serious consideration as to potential attractants they may offer to hazardoux bird species. Although collisions with small, 76 solitary birds can result in damaging stokes to aircraft, generally small passerine birds (e.g. kinglets, sparrows, finches, juncos, goldfinches, etc.) that are typical of wooded areas do not pnse a significant threat because they tend to stay close to the forest edge. Because of their size, behavior, and propensity to flock, gulls, shorebirds, starlings, blackbirds, and waterfowl (e.g. Canada geese, mallards, widgeons, teal, etc.) oven present veritable hazards to aircraft. In addition, birds of prey such as hawks and nwlx are prone to collide with aircraft due to their soaring and foraging behaviors. Vegetation should be selected that will discourage heavily utilization by these more 1137ardnns (in terms nfbird strike potential) species, and it should not attract new species that are presently absent In addition to vegetation management, there are a number of other methods that can be used to discourage birds from ruing the airfield. On page 72 of the F.IS, second paragraph, it was noted that dredging of the delta in 1993 resulted in a higher use of the airfield by displaced birds, presumably gulls. As we understand it the current project dnes not prnpme In dredge the delta itself, but the river entrance to the delta. While the birds in the delta may not be displaced by a * Aetus . e,a —.. A--r.. A.....m„r. A-33 \\\} } �(}\) /}2§ ■ ; )§£}){5|) ! 2 ( .|) E;_ \ 72 E , 7{ / � tF UNITED STATES ENVIRONMENTAL PROTECTION AGENCY "" ` REGION 1200 Sixth Avenue Seattle, Washington 98101 May 21. 1997 Reply'ro Ref: 95-136-COF. All. Of: ECO-088 Merri Martz Environmental Resources Section U.S. Army Corps of Engineers P.O. Box 3755 Seattle, Washington 98124-2255 Dear Ms. Martz The Environmental Protection Agency (EPA) has reviewed the Draft Environmental Impact Statement (draft EIS) for the proposed Cedar River Section 205 Flood Damage Reduction Study in accordance with our responsibilities under the National Environmental Policy Act (NEPA) and 5309 of the Clean Air Act. The draft EIS analyzes four action alternatives and a no action alternative to provide 100 year flood control along the lower 1.25 miles of the Cedar River in Renton, Washington. The draft EIS identifies the minimum dredging alternative as the preferred alternative. Based on our review, we have assigned a rating of LO (Lack of Objections) to the preferred alternative. This rating and a summary of our comments will be published in the Federa! Register. We have enclosed a summary of the rating system we have used in our review for your reference. We note that the detailed project report (DPR) and EIS focus on the initial construction volumes and actions with regard to dredged material disposal, although noting that maintenance dredging of approximately 171,000 cubic yards will occur about every 3 years. The documents reviewed do not address the disposal of these future anticipated volumes. EPA understands that this cee is because the federal governments' primary involvement with this project under Section 205 2 authority will be with the initial construction. Responsibility for the future project maintenance will belong to the City of Renton (the local sponsor). To the extent that fixture maintenance dredging and disposal continues to utilize the "Narco" site, future federal action would likely not be needed. Use of other disposal sites (c g., PSDDA, or especially nearshore sites involving "waters of the United States") would likely require specific permitting. In those cases, while the dredging itself would be regarded by EPA as a maintenance action covered by these documents (hence, no further mitigation would be requested), mitigation of disposal effects would need to be assessed at that time as part of the regulatory review. To minimize future conflicts, we encourage the local sponsor to consider development of a long-term dredged material management plan, similar to what is required for Corps dredging projects. 0 ►mate—R-y~O.r - A-35 Additionally, should the local sponsor fail to maintain this project, as occurred in the past and described in the DPR and HIS, and flooding reoccur, P.PA again would consider the project to have been abandoned and would consider any subsequent dredging to be "new" work rather than "maintenance." Thank you for the opportunity to review this drafl HIS Should you have any questions, please feet to contact John Malek of our Sediment Management Program at (206) 553-1286. Sincerely, 4ichard R. Parkin, Manager Geographic implementation Unit A-36 ar.lrerv.nt.l .rots.tee A ..... ... Ing Eye— far Draft wn.lrenNaetei try+et 4—ateeet, D./lntltene aM r. l 1..-pp Aeelen• (m.IealEf.ae.i t.airt_aLsnallatla■ [O L.ck at abl—I.... The Rnvlrnn..ncAl Pret,c[Inn Ag-- y IPPAI r,vier he- not Id. ifi.d any pet•ntl.l •nvlrnn.wnr .1 fwp+ete rn.r�lrinq Pub-t.ntiv, rhango• to the pregnA.l. Tha rwv/•r .AY h-., Ale•laaod eppereunitlr- for +Ppllc.clen n, wi elq+C lon *•+. �rw• that tould h+ ,eel+pll, had .Irh ne wnr• than el nor ehanq•- co th+ ptrpn++l. aG - Snrlram.e.lal Co...—. Thw EPA r.vlar h.a IA.nc lf4.A •nv/rnnw ,l Iwp+rt• that Mold 1•o a i4pA In ardor to fafnr.rr fatly P tha .nviren.•nt. netiva w.,n way requlrr eharq•• to th, prof nrr•A +I e•rn+t{rA at nppil<+t fan of .Itlg.tinn nw+-u r,aothat can reduew,tM,w lap+et-. a0 an vlrnnw•ntal objection• Th• CPA f Il Ice• Id•ntlfl.A ctgntti,.nr. •nvlro..•. t.l l.p•cta that -hnuld he-rnlA-d In nrdar t Pro"". +Mqu.ta pretnetten fer CM •nvlrenwent. [err•rtivw w w.Y r+•p•1 re n,b,eantl.I ehangwa thw ps•[.rred eft. ro.t lve et eonAld•r.c lnn of • ether projwet .It.%•tly. Ilncludlaq tha n .eslnn .Itv rn.ctva or + n.r .lt•rn.tlral. EPA Intend- to .ark .11h th, lead .q..tV cn rw.h�ce ehw,+ I.p.e[..o• A - - R tl..... .it, tln as cl.tectery The EPA rAvi.. hen Id,n[Iff"I +Avroa onvlranwwnr +l 1-part1 that ate of aufflcl-nt „agnlluA, that dray AreA.elef.etery I— th. ,t+ndpolnt of pnhlie health or ..Ifat, n n.iretu++ j •fu+ilty. EPA intend, to .nrk 'rich th+ I.,d ay,n y to radue, tha„ Iwp. cr 1! me pnt•nclAlro .CIAl.ctory lwp.e not a wet aA the final all .tag,, thi. Prapaul -ill be r..w d.d ter r•f.rr+lnce tM emmcll en wnv*I:: •ntalfOu.11ty [CFO). ldwmaer ee eb. [,mace at.[�l� Category t • - AAewat. EPA MI1•vo, the draft CIS ad.T,atdy eat, forth the envlrnnw,ntal i.pAetl-I of the pf.ferr.d •It. rn.tly. -nA !M-, of tha Alt. rn. clue• r +ean•bly +vall.hl. to th• prnjwrt or +etlan. Ne lurth.r .n.ly.l• e[ A.C. •-fleet lon 1• nee .,u ry, but CA• rwvlwe[ any nggw e[ [M adAltlon of 11.1lfy4nq I.nqua q. n lnfor.,tLnn, r Gee eg,.ry [ - - f... tfi.i_ tof.—tlee The draft EIS An.. no' "A'"' ,uf [Icl•nt IntoreAtton tar PPA to fully ,a ... ...Jrmaa+nt,l 1a•Paec, that ,hmt1A be .velAM In nrMr to fu IIY prat wec 111, •a-Iream—, or he EPA fevl...f has ld,ntifi•d n n.hy -..11.hlw .It. rn.[lr,- that • rlthln the•1[+rn+tire• .n.lyx ed In thw Ar-It AS .h1eh ""d re"erw tha •I.lrnnn.nt.l le,-. of the .cclnn. Thw ld,nt lllaA .Adl tlen/1 (near.+[Lon. dwt -, .n.lY-•- or A/atu--lnn Mmtld h. lntlud,d in the final EtS. Cate.." ] - lnwA •qua to -FA M+- —1 halls, that Ina draft wim A4.T,,tely + ••A pnt•nt1.ItY algnlflcent •ntr.n.. ,I I wparc• of the .mien, o the EPA revl+.ar he. Id•ntifldi n n.biy . 11eb1& .lt-rn+tly+A that + amtt-IAe of th ,pace tu. of +l to rn.t lv-• analyzed in the draft 114. leh ,heuId be eha lYr ad In •char Corr Mue, th• pnt.nt l,llY al gn/[leant •nv7rnm„nt .1 I.peet.. SPA b+flue. that the IA•ntitled -ddltional Inraf.+clan. ly-ae, r dlAeue,len ar e! ,unh , wngnituda that th.y -hnuld h.r, full Plbl�< caul.+ at • Areft .tnOa.• RPA M•e net hwltavw rhac+tM dr+/[ Sfl la eA+qu+e- far rh- Ptrpn. •a nL tha N.tlnn.l Rnvl ron.ont+l Inll.y Act and or ,actin. loq _1.., +M rha, ,hnulA he fnt.aily r•.I,N .nA .ad, ..+11+h1w fer P,hllc e In . .urrl•.•nt+l n w i..A Ar aft Ef q. On tM b+Al• of rho "I ... l+1 •Ignlrl... t Iwp+cc• Invlv,A, thl- ,nt p rnpn,al cnulA M , .♦ndld,t, lnr r,f nrrel tp !AA CEO. • rro, /rA ILntIltlliSD Pollr .nd�Dswdu[nilnt..thf�AtYlar of r.dw[ALAWOM—LmAcilnuhw3nylcenmwnt Ioh n�A ry, I//l. A-37 United States Department of the Interior 8 OFFICF OF THESECRETARY (Mn nl Fn.v --1 NJ— rid c—plunrr NF. hl d--h 4w, Suur rM �qCN) `°,� I•vdand. fl,exnn �:`IrIO V: May 9, 1997 ER 97/0194 Colonel Donald T. Wynn District Engineer Seattle District, Corps of Engineers P.O. Box C-3755 Seattle. Washington 98124 Dear Colonel Wynn The Department of the Interior (Department) has reviewed Draft Environmental Impact Statement (DEIS) for the Cedar River Section 205 Flood Damage Reduction Study, King County, Washington The following comments are provided for your information and use when preparing the Final Environmental Impact Statement (FEIS). GENERAL COMMENTS The Fish and Wildlife Service (FWS), the local Tribes, and other resource agencies have worked closely with the Corps of Engineers (COE) during the feasibility phase of this project. We are pleased to see many of the suggestions developed by these resource agencies have been incorpnrated into the preferred alternative. Several studies completed by the COE or their consultants have helped to clarify project impacts. The Department supports the preferred alternative as described in the DEIS as long as the proposed mitigation is fully implemented. Any changes from the preferred alternative or the proposed mitigation should be discussed with the FWS, and other resource agencies. The preferred alternative, the Minimum Dredging Combined with Levees and Modifications to the South Boeing Bridge alternative, includes dredging the Cedar River to a depth of 4 feet from the mouth to Logan Avenue. From Logan Avenue upstream another 800 feet, the dredging depth would gradually slope up to the present streambed elevation. Levees or berms would be constructed from Williams Avenue downstream to contain flood waters. The South Boeing Bridge would be fitted with hydraulic jacks to allow the bridge to be lifted during high Bow periods to prevent debris jams. The Department prefers this alternative because it would provide a good combination of flood control measures and fish and wildlife resource protection. The Existing Channel Depth with Levees and Modifications to Snnth Boeing Bridge alternative called for only dredging to maintain the existing channel depth and levee construction. Even though it may have slightly less impact on the aquatic resources, the constant disturbance to the stream by A-38 _3E _ - _ Nc-_-. 78. Editorial changes made as appropriate. 79. Concur. See additional detail in section 4.3. 80. The WDFW sockeye fry trap is recalibrated every year currently due to a highly variable sediment input/scour in the lower river. The Corps is planning to move the fry trap to a location selected by WDFW during construction, however recalibration does not need to occur 2.3 years in advance of construction. 81. Tall native tree species will be incorporated as feasible. There are safety concerns within the park regarding the use of cottonwoods and some other large trees. 78 Colonel Donald T. Wynn, District Engineer dredging every three years would mask any significant difference in impacts. However, the disturbance to the riparian zone seems to be greater in this alternative, thus, this alternative would have a greater impact on terrestrial animals. SPECIFIC COMMENTS CDycr bge - The cover pages of both the DEIS and the technical appendices should be dated March 1997 instead of March 1996. Eage_18—Eituce6..SeWoml-2 - Addition of grid lines for each elevation would clarify Figure 6. tages� 6Z...Secliott4.i - This section provides a discussion of the direct effects of the project on 79 specific fish species. This discussion should include the interaction between the species due to changes in populations. For example, some concern about the interaction exists between long -finned smelt and sockeye fry since both of these species feed on lake plankton. This impact and other inter - specific impacts should be fully discussed in the impacts section. Eat es_$L-_12—Sectlon-5 - The mitigation plan adequately compensates the project impacts. However, the Washington Department of Fish A Wildlife (WDFW) fish trap may he jeopardized by 80 this project, and we suggest relocating it to a site mutually agreed upon by the COE and the WDFW. This should be done two to three years in advance of actual construction to allow collection of baseline data and development of a comparative curve. CageB3.Seelitm5.5 atagtaphl - The tree species used to revegetate the disturbed riparian areas 81 should include several tall native species, such as conifers and big leaf maple to increase the spatial heterogeneity within the limited riparian zone. Page63—SeClion-5 6 - The Monitoring Plan section should be numbered 5.6 instead of 5.5. Fage63. Sesdon M - The monitoring plan is the key to the success of the project. The monitoring section of the mitigation plan seems adequate for the project. Any changes to the monitoring plans or its safeguards to insure revegetatinn and any monitoring results should be provided to the FWS in a timely manner. The FWS would remain involved with this project through its construction and monitoring phases. Page43—Refere=cSeetion - Several references in the DEIS were not cited in the References Section. Their citations should be included in the FEIS. We thank you for this opportunity to comment on this project. Sincerely, \ -:Q J 's, Preston Sleeger Acting Regional Environmental Officer A-39 &v US Dpcartment of Tronsocy farm federal Avrotlon Adminislrallon May 30, 1997 Merri Martz Environmental Resnorces Section U.S. Army Corps of Engineers P.O. Box 3755 Seattle, Washington 9RI24-2255 Dear Ms. Martz: s..w. Al,Cmr. 01.10s1 amc. 1601 L-nd Av w nn.. S W nwn,On, WA GROSS .OSA We have reviewed the Draft Environmental Impact Statement for the Cedar River Section 205 Flood Damage Reduction Study as well as the letter from Mr. Michael A. Linnell of USDA Animal Damage see Control. While we are supportive of du effort to address the flooding problems adjacent to the Renton 77 Municipal Airport, we do concur with Mr. Linnell's comments regarding the potential for bird strikes As noted in his letter, we do look to USDA Animal Damage Connol for technical and operational assistance to reduce wildlife hazards to aviation. In an effort to ensure the safety of aircraft operations at the Renton Airpnrt, we support the recommendation to analyze the bird hazard issue as a part of the EIS and provide mitigation measures in the event that a potential hazard is created by the project. Attached please find not recently finalized Advisory Circular on this issue. If you wish to discust this further, please do not hesitate to contact me at (425) 227.2653. Sincerely, 4 C RI ernT4Airt nvironmentai Specialist cc: Michael A. Linnell, USDA - Animal Damage Control. WA, AK Gail Reed, Renton Municipal Airport A-40 RFWor.___;: 82. During Plans and Specifications, the Corps will evaluate the feasibility of dredging within the work window. If it is possible to reduce dredging time, it will be accomplished. �t Stale of Washington DEPARTMENT OF FISH AND WILDLIFE Marling Adrlmss: 500 Capild Way N • Olympia, WA 98501.1091 • (.WiO) 902.2200, TDD (3F;n) 902.7207 Main OORe Lncalion. Natuml nesources Roldinq • 1111 Washmglon Street SE • Olympia. WA May 5, 1997 Merri Martz Environmental Resources Section ATTN: Cedar River EIS U.S. Army Corps of Engineers Post Office Box 3755 Seattle, Washington 98124-2255 SUBJECT: DRAFT ENVIRONMENTAL IMPACT STATEMENT, CEDAR RIVER SECTION 205 FLOOD DAMAGE REDUCTION STUDY, Cedar River, Tributary to Lake Washington, King County, WRIA 08.0299 Dear Ms. Martz: The Washington Department of Fish and Wildlife (WDFW) has reviewed the above -referenced document and submits the following comments. WDFW appreciates the opportunity to review and comment on the document and the significant and thorough effort the Corps has made to produce it. The Corps appears to have done a very fine Job of addressing the issues, which promotes the confidence of WDFW that the project can be conducted In a manner to sufflcently protect fish and wlldllfe resources. WDFW concurs with the Corps' selection of the minimal dredge alternative as the preferred alternative. This alternative appears to make the most sense, when combined with improvement of the levees within the project reach, to avoid and minimize Impacts while achieving the project objectives. The projected rates of resedimentatlon seem to indicate that dredging more than minimally would not result in significantly greater flood hazard reduction, though Impacts to fish resources would increase substantially. The minimal dredge alternative appears likely to produce lesser Impacts to water quality than the moderate dredge alternative, due to greater ability to successfully implement water quality BMP's during minimal dredging. I recommend a preferred work window for the Cedar River of July 1 through August 31, due to use of the habitat by steelhead, lake 82 run, and resident trout prior to July 1 and by adult salmon after August 31. A-41 see 35 A-42 USACE-Martz Page 2 May 5, 1997 WDFW concurs that a groundwater fed spawning channel would be an appropriate means of mitigating project Impacts on sockeye salmon spawning, though it I don't know whether there would be adequate room at the Elliot Levee site to construct another groundwater fed channel. WDFW suggests using the Timber, Fisher, and Wildlife protocol (which, I believe, is lit or 12%) for acceptable threshold levels of fine sediments in spawning substrates. Monitoring and maintenance of the channel should occur for as long as maintenance dredging occurs in the lower river. The channel needs to be effective to mitigate ongoing Impacts of maintenance dredging. If there are any questions regarding this letter, I can be contacted at (425) 392-9159. WDFW appreciates your cooperation In our efforts to protect, perpetuate, and manage the fish and wildlife resources of the state of Washington. SIInnce�r�ely,� Larry Fisher Area Habitat Biologist Habitat Management Program if CC! WDFW, Muller WDFW, Banyard MIT Fisheries, Malcom USFWS, Stagner KCWLRD, Lucchetti APPENDIX B U.S. FISH & WILDLIFE SERVICE FISH AND WILDLIFE COORDINATION ACT REPORT WITH RESPONSES BY THE CORPS TO RECOMMENDATIONS IN THE REPORT CEDAR RIVER SECTION 205 FLOOD DAMAGE REDUCTION STUDY Fish and Wildlife Coordination Act Report U. S. Fish and Wildlife Service North Pacific Coast Ecoregion Western Washington Office Olympia, Washington February 1997 Fish and Wildlife Coordination Act Report CEDAR RIVER SECTION 205 FLOOD DAMAGE REDUCTION STUDY Prepared for U.S. Army Corps Of Engineers Seattle District Prepared by Gene Stagner, Biologist U.S. Fish and Wildlife Service North Pacific Coast Ecoregion Western Washington Office Olympia, Washington February, 1997 TABLE OF CONTENTS INTRODUCTION..........................................................I AUTHORITY AND DOCUMENTATION ....................................... 1 PROJECT LOCATION AND DESCRIPTION ..................................... 2 Location............................................................2 Project Alternatives Descriptions .......................................... 5 FISH AND WILDLIFE RESOURCES ........................................... 6 Wildlife Resources..................................................... 6 Fish Resources........................................................9 THREATENED AND ENDANGERED SPECIES ................................. 17 STUDY RESULTS.........................................................18 WildlifeStudy.......................................................18 Predator Study.......................................................19 Longfin Smelt Study..................................................20 Habitat Study/Survey.................................................. 21 Sockeye Salmon Spawning Survey ........................................ 22 Fish Utilization Studies ................................................ 22 Aquatic Invertebrate Study .............................................. 22 FUTURE WITHOUT THE PROJECT .......................................... 23 POTENTIAL PROJECT IMPACTS TO FISH AND WILDLIFE RESOURCES ........... 24 Impacts to Wildlife...................................................24 Impacts to Aquatic Resources ........................................... 25 NoAction....................................................25 Alternative...................................................25 Alternative 2...................................................26 Alternative ...................................................27 Alternative4...................................................27 RECOMMENDATIONS..................................................... 28 Mitigation for Wildlife Impacts ........................................... 29 Proposed Mitigation for Aquatic Resource Impacts ........................... 30 LITERATURE CITED ...................................................... 33 LIST OF TABLES Table...................................................................7 Birds observed in the vicinity of the lower Cedar River Table..................................................................10 Resident and anadromous fish species utilizing the Cedar River Table ............. 11 ..................................................... Sockeye Salmon redds observed in the lower Cedar River, 1994 and 1995 Table4..................................................................16 Smelt egg distribution in Lake Washington tributaries LIST OF FIGURES Figure...................................................................3 Lower Cedar River Section 205 Project Vicinity Map, City of Renton, King County, Washington Figure...................................................................4 Lower Cedar River Section 205 Project Location Figure..................................................................11 Cedar River Salmon and Steelhead Periodicity Chart Figure..................................................................13 Cedar River Sockeye Escapement Figure..................................................................15 Anadromous Fish Returns to the Lake Washington Basin and Cedar River INTRODUCTION This is the final Fish and Wildlife Coordination Act Report (FWCAR) for the Lower Cedar River Section 205 project. It fulfills the Scope of Work (SOW) for the U. S. Fish and Wildlife Service's (Service) feasibility -level activities as described in the Army Corps of Engineers (Corps) Military Interdepartmental Purchase Agreement (MIPR) # E-86- 97-3035. It has been prepared pursuant to Section 2(b) of the Fish and Wildlife Coordination Act (48 Stat. 401, as amended; 16. U.S.C. 661 et seq.) and supersedes our draft FWCAR of October, 1996. After reviewing all of the pertinent information, we support the shallow dredge alternative (discussed in a later section as alternative 2). The impacts to fish and wildlife resource seem to be minimized with this alternative. The flood control objective of the project should also be accomplished with this alternative. This report is being sent to the Corps, several state and local entities, and the Muckleshoot Indian Tribe. The Service plans on being involved through the implementation of this project. We will be available to support the Corps during the development of the mitigation and monitoring plans. AUTHORITY AND DOCUMENTATION Section 205 of the 1948 Flood Control Act as amended allows the Corps to construct small flood control projects not specifically authorized by Congress. Each project is limited to a Federal cost of not more than $5 million including studies, design, plans, specifications, and construction costs. The costs for both the preliminary evaluation and the feasibility stage are cost shared with a local sponsor. The City of Renton (the local sponsor) will bear the maintenance costs for the project. This report is based on project plans and information provided by the Corps through January 29, 1996. It uses results from studies conducted by the Corps, private contractors, the Service, the Washington Department of Fish and Wildlife (WDFW) and Muckleshoot Tribal biologists. The Project Impact and Mitigation portions of this report are based on consultation with the above entities as well as comments from agency and public meetings. As a result of the initial appraisal, the Corps has determined that there is a federal interest in participating in flood damage reduction measures along the lower Cedar River in the urban/industrial area in the City of Renton, King County, Washington. Average annual flood damages for the lower one mile of the Cedar River have been estimated at $670,000. In November 1990, flooding in this area reached the highest level recorded at Renton since 1945 and caused an estimated $8 million in damages to the Renton airport and Boeing manufacturing plant. The 1995/1996 floods also caused significant damage to City and private property. The Corps has indicated that flood reduction benefits exceed costs for a structural solution and has initiated feasibility level study. Historically, the lower Cedar River was dredged periodically to a depth of >10 feet. This was expensive and created a need to dredge the delta area. The delta created the control level for water flow into the lake and therefore limited flow if it was not dredged to an equal depth as the channel. Due to the recent flooding along the lower Cedar and the significant damage incurred, alternative methods for flood control are being investigated by the City of Renton and the Corps of Engineers. An interagency scoping meeting was conducted on June 12, 1996, to discuss the latest flood control alternatives and solicit agency issues. These issues should be addressed in the Environmental Impact Statement (EIS) and in the design report. The discussions focused on fish and wildlife resource studies, and impacts of the projects on these resources. Sediment traps and transport were discussed and five (5) alternatives were presented. The no action alternative will be evaluated in context during the EIS. Consequent phone discussions with the Corps indicated that the sediment traps would not significantly delay the frequency of lower channel dredging so that alternative will likely be dropped from future consideration. The remaining alternatives with various permutations are discussed below. PROJECT LOCATION AND DESCRIPTION LOCATION This proposed project involves the Cedar River from the mouth at Lake Washington upstream approximately one mile. It is entirely within the city limits of Renton. The Cedar River watershed is located about 16 miles southeast of Seattle entirely within King County (See Figure 1). The headwaters begin within the boundaries of the Mt. Baker - Snoqualmie National Forest. The drainage basin is about 50 miles long and encompasses an area of approximately 186 square miles. The Cedar River cuts a canyon through steep mountain terrain from its source to Chester Morse Lake at about rivermile (RM) 37.2. This relatively small reservoir angles west about 1.5 miles to Masonry Dam (RM 35.9). From Masonry Dam, flow is diverted through penstocks to Seattle's Cedar Falls Power Plant located about 3.5 miles west. At this point, the entire flow returns to the main Cedar River channel. Downstream to Landsburg, the river channel initially occupies a steep, well-defined channel that gradually widens and moderates in steepness. At Landsburg, water is diverted into a pipeline which transports it to Lake Young Reservoir southeast of Renton. The diversion dam at Landsburg (RM 21.8) blocks anadromous fish runs from using the upper basin. A Habitat Conservation Plan (HCP) is currently being negotiated for lands owned by the City of Seattle in the upper Cedar River. If this plan is implemented, Seattle has agreed to fund fish passage around the Landsburg dam for chinook salmon, coho salmon, and steelhead trout. Sockeye salmon will not be allowed passage above the dam due to a concern for water quality given the larger number of adult fish. Steelhead trout were hauled around the dam historically but this has not happened in the last few years. F1 The Cedar River from Landsburg to Maple Valley (RM 14.7) flows through a relatively shallow, narrow valley with moderately steep hillsides. Stream gradient in the upper 2 miles of this section is moderately steep with fast rifles and large rock and boulders. Downstream, the gradient decreases and is moderate for the remainder of this section. Several steep gravel banks border the stream throughout the upper 5 miles. Erosion from these contributes fine sediment as well as vital spawning material to the river below. N g Coal Cr. 0 u May Creek Ced / ar Project Area Lake Youngs Seattle Water Diversion Pipeline J Creek Evans Creek Lake Sammamish P C Landsburg Dam Lower Cedar River Section 205 Project Vicinity Map From Maple Valley, downstream to Renton, the Cedar River winds through a broad, flat valley with increasing rural and commercial development. The river maintains a moderate to gentle gradient in 3 this section with a few channel splits and bends with sand and gravel bars. Rural areas exist on both sides of the river valley floor with higher urban densities nearer the population center of Renton. In this section, river banks have received extensive bank protection work, primarily riprapping. The lower 3 miles of the river flow through a heavily industrialized area of Renton. The last 1.25 miles of the river flow through a channelized segment before emptying into Lake Washington (See Figure 2). The effects of development in the lower Cedar River are most apparent from the increased rates and volume of storm water discharge caused by the extensive impervious surface areas of buildings, highways, and parking lots. This has resulted in substantial bank erosion, increased siltation, and frequent floods in the vicinity of Renton. Water quality and fish habitat have deteriorated as a result. Figure 2 Lower Cedar River Section 205 Project Location (Not to Scale) 1.2 Oceanic storms, usually lasting from 1-3 days, cause major floods on the Cedar River. Warming temperatures from these storms are sufficient to melt a significant amount of the snowpack. Successive storms can cause a series of floods which most commonly occur from October through June during those periods of intense rainfall or rapid snowmelt. The Cedar River supplies 54 percent of Lake Washington's water supply, which is important to the operation of the Hiram Chittenden Locks for commerce, for ship passage, and control of salt water intrusion. Lake levels of Lake Washington are maintained at +20 foot M.S.L. during winter and increased to 22 feet for summer operation of the locks and fish ladder when precipitation and other Lake Washington inflows are low. PROJECT ALTERNATIVES DESCRIPTIONS The Corps has considered several preliminary alternatives to control flood damage in the lower one mile of the Cedar River. During feasibility stage planning, four action alternatives are being evaluated by the Corps to establish which is the most cost effective and most environmentally acceptable. All of the following alternatives include the addition of a hydraulic jack to the south Boeing bridge. The latest action alternatives include: Constructing levees along the right bank from Logan Avenue to the mouth and on the left bank from Logan Avenue to a point 2,000 feet above the mouth. There would be maintenance dredging every three years to maintain the existing channel bottom. 2. Dredging the lower mile of river a moderate amount (4 feet) to the Logan Avenue bridge. From the Logan Avenue bridge the dredging would slope upstream for 400 yards to meet the present gradient. This alternative will include constructing a levee/floodwall along the bank. The height would range from .58 - 6.92 feet, depending on the existing bank height. Maintenance dredging of 171,000 yds3 would be required every three years. 3. Dredging the lower mile of river a deeper amount (6 feet) to the Logan Avenue bridge. From the Logan Avenue bridge the dredging would slope upstream for 700 yards to meet the present gradient. This alternative will include constructing a levee/floodwall along the bank. The height would range from 1.36 - 5.83 feet, depending on the existing bank height. Maintenance dredging of 176,000 yds3 would be required every three years. 4. Dredging the lower mile of river up to 10 feet deep to the Logan Avenue bridge. From the Logan Avenue bridge the dredging would slope upstream for 700 yards to meet the present gradient. This alternative will include constructing a levee/floodwall along the bank. The height would range from .63 - 5.43 feet, depending on the existing bank height. Maintenance dredging of 185,000 y& would be required every three years. 5 The proposed levees would consist of filling in between the existing mounds on the right bank. The levees would not encroach on the river and would be set back from the river's edge to allow for riparian zone planting. On the left bank (the airport side), sheet piling combined with raising the roadway to form a berm would be used to protect the airport. The south Boeing bridge creates a debris trap during floods and would require higher levees upstream of the bridge to accommodate the backwater effect caused by debris blockage. The proposed solution to this is to construct hydraulic jacks under the bridge and jack the bridge up during flood events to reduce the potential for debris blockages. This feature is included with each alternative. Two dredging methods have been proposed for this project. A barge mounted clamshell dredge could be used since the water depth is adequate to float the barge. In conjunction with the clamshell a barge mounted dragline could be used in the lower portion of the project area. The other method considered is to divert the water by coffer dams and remove the gravel from the contained area by excavator. FISH AND WILDLIFE RESOURCES WILDLIFE RESOURCES Terrestrial wildlife species and wildlife habitat in the study area are limited due to the amount of industrial and commercial development. However, many different wildlife species can adapt to these environments. In fact, the diversity of bird species in the project area is significant. A narrow band of riparian vegetation occurs discontinuously at the waters edge. Bird species are the most prevalent wildlife using these areas. The lower Cedar River is used by several groups of bird species such as songbirds, waterfowl, shorebirds, wading birds, gulls, hawks, and eagles. Gulls are probably the most abundant group of birds in the area. One of the reasons for dredging the Cedar River delta in 1994 was to reduce the risk of aircraft and bird collisions at the Renton airport. The shallow gravel bar areas attract many birds, primarily gulls. These birds were presumed to increase the risk of collision with aircraft landing or taking off at the airport (COE 1993). Sixty-four different bird species were recorded during surveys completed by Service, Corps and Harza Northwest biologists (Table 1). These surveys were completed between March, 1992 and September, 1995. Many of these birds were using the project area for breeding and rearing. Smaller birds breeding in the area included bushtits, swallows, red -winged blackbirds and hairy woodpeckers. A male woodpecker, accompanied by a female, was observed excavating a hole in one of the few alder snags in the area. The number of broods and young of the year observed indicated that this area is getting substantial use for nesting and/or rearing. Juvenile gulls, mallards, common mergansers, and Canada geese were observed in the project during most of the spring and summer. Bushtits, hairy woodpeckers, barn and rough -winged swallows, house sparrows, and red -winged blackbirds were observed either nesting or with young of the year. Riparian zone areas are extremely valuable to wildlife. Their value is due to their shape and proximity to water. They provide large edge -to -area ratios from their linear nature and varying soil moisture that support a greater diversity of plant species. Of the 480 species of wildlife in Washington, 291 are found in wooded riparian habitats. Of these, 68 species of mammals, birds, amphibians, and reptiles require riparian areas to satisfy vital life requirements for all or part of the year. Table 1. Birds observed in the vicinity of the lower Cedar River. (Brunner 1995) (USFWS 1995) 1993 Species Scientific Name 11 Species Scientific Name Horned grebe Western grebe Double -crested cormorant Great blue heron Green heron Canada goose Green -winged teal Mallard Northern Shoveler Gadwall Canvasback Redhead Lesser Scaup Common goldeneye Barrow's goldeneye Bufllehead Hooded merganser Common merganser Domestic ducks Bald eagle Cooper's hawk American coot Killdeer Western sandpiper Mew gull Ring -billed gull California gull Herring gull Thayer's gull Glaucous -winged gull Rock dove Vaux's swift Podiceps auritus Aechmophorus Phalacrocorax auritus Ardea herodias Butorides virescens Branta canadensis Anas crecca Anas platyrhynchos Anas clypeata Anas strepera Aythya valisineria Aythya americana Aythya aff Snis Bucephala clangula Bucephala islandica Bucephala albeola Lophodytes cucullatus Mergus merganser Spp, ? Haliaeetus leucocephalus Accipiter cooperii Fulica americana Charadrius vociferus Calidris mauri Larus canus Larus delawarensis Larus californicus Larus argentatus Larus thayeri Larus glaucescens Columba livia Downy woodpecker Hairy woodpecker Northern Flicker Tree swallow Violet -green swallow N. Rough -winged swallow Cliff swallow Barn swallow American crow Northwest crow Black -capped chickadee Chestnut -backed chickadee Bushtit Bewick's wren Winter wren Ruby -crowned kinglet American robin European starling Yellow warbler Yellow -romped warbler Common yellow throat Wilson's warbler Spotted towhee Song sparrow Golden -crowned sparrow White -crowned sparrow Red -winged blackbird Brewer's blackbird House finch House sparrow c_,eryie aicyon Picoides pubescens Picoides villosus Colaptes auratus Tachycineta bicolor Tachycineta thalassina Stelgidopteryx ruficollis Hirundo pyrrhonota Hirundo rustica Corvus brachyrhynchos Corvus caurinus Parus atricapillus Parus rufescens Psaltriparus minimus Thryomanes bewickii Troglodytes troglodytes Regulus calendula Turdus migratorius Sturnus vulgaris Dendroica petechia Dendroica coronata Geothlypis trichas Wilsonia pusilla Pipilo maculatus Melospiza melodia Zonotrichia atricapilla Zonotrichia leucophrys Agelaius phoeniceus Euphagus cyanocephalus Carpodacus mexicanus Passer domesticus Riparian areas also maintain the health of the stream by providing large woody debris to the stream, creating storage for overbank flood flows, trapping sediments and pollutants, moderating temperature extremes, and providing organic material. Even small areas of riparian zone habitat are important to a stream's health. This important habitat has been greatly reduced on many of the Lake Washington basin rivers as the area becomes more urban. Pressure will continue to be exerted on riparian zone habitat as the Cedar River basin is developed. Since the riparian zone in the project area is greatly reduced from its historical extent, the remaining riparian zone is even more valuable. Riparian vegetation in the project area is very limited on the west or left bank, especially adjacent to the airport. Willows, a few short alders, and a mix of non-native weedy species, mainly blackberry, account for most of the vegetation. The east or right bank is more diverse with scattered overstory tree species such as alder, willow, and cottonwood. Cultivated trees such as oaks, maples, and conifers have been planted along the trail system. These trees provide perching, nesting and foraging habitat for birds. Many bird species were observed foraging in the trees and shrubs near the river. A few areas contained a mix of trees, shrubs and herbaceous vegetation. These areas provide the greatest wildlife habitat value in the area. Overhanging vegetation is limited, but furnishes a small amount of cover for duck broods and aquatic furbearers. Grazing habitat is provided to ducks and geese in the form of cultivated and mowed grass associated with the trail/park system. Neotropical migrants are land birds that breed in Washington yet migrate to the neotropics, like Mexico and Greater Antilles, during the winter. Over one half of our breeding birds are neotropical migrants (Morton and Greenberg 1989). Passerines (perching or songbirds) make up the largest group of these birds and include birds like flycatchers, thrushes, sparrows, waxwings, and warblers. Many of these birds rely on the riparian areas by the river for breeding. Fifty-three percent of all neotropical migrants are associated with these riparian areas and 67 percent of the species with known declines use these habitats. A recent review of Washington's neotropical migrants by Andelman and Stock (1993), supports the need to concentrate our efforts on preserving or restoring habitats for these birds. Riparian habitats were identified as a priority habitat for species with known population declines. Sixty-eight of the 120 bird species breeding in Washington use riparian areas. Thirty-one percent of these species are habitat specialists and depend on only one or two habitats for breeding. Andelman and Stock (1993) found severe long-term population declines in several of these riparian species that include the gray catbird; the Wilson's, yellow, and orange -crowned warblers; eastern kingbird; solitary vireo; rufous hummingbird; barn swallow; and song sparrow. They also identified several species that are habitat specialists (i.e., use two or fewer habitats) and have localized breeding populations. The species that use the riparian zone heavily include Vaux's swift and MacGillivray's warbler. Andelman and Stock (1993) identified riparian zone habitat as one of the highest priority habitats to protect. Many of the plant species present are on the State noxious weed list or are extremely invasive. These include Japanese knotweed, Himalayan blackberry, Scotch broom, reed canary grass, and morning glory. This vegetation provides brushy areas that are the preferred habitat for some species. However, the nature of these species dictates that aggressive control is needed to avoid displacement of native species that are more valuable to wildlife. Snag habitat is almost non existent which severely limits primary excavators (woodpeckers) and the dependent cavity nesters. The downy woodpecker and hairy woodpeckers seen during the survey were utilizing one alder snag located in the park. During the spring of 1995, nesting bird boxes were installed on posts along the riparian zone by the local Audubon Society. These will help provide cavity nesting habitat but are a poor substitute for actual snags. Mammal species were not as prevalent nor as obvious. This type of habitat in other areas has supported mammals such as raccoons, skunks, opossum, mice, rats, eastern gray squirrels, and river otter. FISH RESOURCES At least 20 species of resident and anadromous fish species utilize the Cedar River including chinook, coho, and sockeye salmon and steelhead trout. The Cedar River contributes an estimated 40 percent of the wild fall chinook salmon to the Lake Washington Basin, 12 to 25 percent of the wild coho, and 25 percent of the wild winter -run steelhead trout. The largest sockeye salmon run in the lower 48 states spawns in the Cedar River, including the majority (80 - 90 percent) of Lake Washington sockeye. One of only two landlocked longfin smelt populations in North America utilizes Lake Washington and the Cedar River (Hart 1973). Sculpins, mountain whitefish, western brook lamprey, speckled dace, and three -spine stickleback are also found (Wydoski and Whitney 1979). Recent studies by the Service and Corps biologists have identified 30 species of fish using the south end of Lake Washington, the delta or project area of the Cedar River. Fish species observed during the studies associated with the Cedar River 205 project are shown on Table 2. These fish may be residents in the Cedar River or may reside in Lake Washington and periodically use the project reach. Sockeye salmon are the most valuable commercial species in the Cedar. Coho and chinook salmon have become less predominant commercial species in the Cedar due to their limited numbers in comparison to the size of the sockeye run. Steelhead trout is a highly valued game fish in the system. Currently, the fisheries of the Cedar River basin are managed for natural production of salmonids. 64 Table 2. Resident and anadromous fish species utilizing the Cedar River or south end of Lake Washington as observed by Service and Corp biologist in 1994 and 1995 studies Mountain whitefish' Yellow perch ' Bull trout Longfin smelt ' Dolly Varden Lar escale sucker ' Sockeye salmon Northern s uawfish Kokanee Lon nose dace ' Coastal Cutthroat trout ' Torrent scul in ' Steelhead trout ' Coast range scul in ' Rainbow trout ' Reticulated scut in ' Coho salmon' Prickly scul in ' Chinook salmon' Blue ill Peamouth chub Brown bullhead ' Smallmouth bass ' Brook lamprey' Largemouth bass ' Atlantic salmon ' Pumpkinseed ' Tench Three-s ined stickleback' Warmouth ' These species were actually found in the Cedar River during studies for this Sec. 205 project. Sockeye salmon spend one year in Lake Washington as pre-smolts before migrating through the Ballard Locks to the ocean. They spend two years in the ocean and then return as adults to spawn. The adults enter Lake Washington as early as July and may begin spawning as early as August. Most spawners, however, enter the Cedar beginning in early September and continue through mid - December with peak spawning occurring in mid -October. A few fish may be found spawning as late as February (See Figure 3). Escapement levels to the Cedar River have ranged from 107,000 to 383,000 adults, with an average of 226,827 between 1964 and 1989. Stober and Graybill (1974) showed that the heaviest spawning activity on the river occurs in the higher quality habitat of the upper and middle river reaches above RM 5.3. The largest concentrations of spawners were consistently observed above RM 11.5. The lower reach below RM 5.3 was the least utilized section of the river. Stober (1975) found no spawners below RM 5.3 during spawner counts of the same study area. Stober and Graybill (1974) also discovered that the early spawners used the upper accessible reaches of the Cedar while the later spawners used the middle and then the lower reach toward the end of the spawning period. This trend seems to be apparent during the December 1994 spawning survey in which twenty-eight (28) redds were located below the south Boeing bridge (See Table 3). 10 Sockeye Spawning Incubation Emergence Fall Chinook Spawning Spring Chinook Holding Spawning Coho Spawning Winter Steelhead Spawning Holding Summer Steelhead Holding Spawning OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP Shoulder 0 PeakLLi Figure 3 Cedar River Salmon and Steelhead Periodicity Chart (from Cedar River IFIM, Seattle Water Department October 1991) Table 3. Sockeye salmon redds observed in the lower Cedar River, 1994 and 1995 Segment Nov. 1 1994 Nov. 16 1994 Dec. 12 1994 Nov. 3 1995 Wells Avenue bridge to William Avenue bridge (RP 18) 53 100 NS* 53 William Avenue bridge to RP 16 (just below Logan Avenue bridge) 99 285 61 133 RP 16 to RP 14 3 52 22 47 Reference marker 14 to S. Boeing bridge 3 24 40 33 S. Boeing bridge to the mouth of Cedar River 0 NS* 28 1 Total redds for surveys area 158 461 151 267 Total redds within project impact zone 6 76 90 81 * Not Surveyed Sockeye spawning surveys were completed by the Corps biologists in 1994 and 1995 from the mouth of the Cedar River up to Wells Avenue. The highest single survey count for 1994 was the four 11 hundred thirty-two (432) redds located on November 16, 1994. Most of these redds were located between the Wells Avenue bridge and just below the Logan Avenue bridge. Seventy six (76) of these redds were located in the proposed project section below reference point (RP) 16 near the Logan Avenue Bridge. Redds observed downstream of the Logan Avenue bridge were confined to the rifle -like areas along the left bank. Only one survey was completed in 1995 (November 3), due to high water and poor observation conditions. In the 1995 survey, eighty-one (81) redds were within the proposed dredging area located downstream of RP 16. The results of these two years indicate a significant usage of the lower Cedar by sockeye salmon. A more extensive discussion of the spawning surveys can be found under the Habitat Survey/Studies section. The lower section, from RP 14 to the mouth, is characterized by deeper water and slower velocities. This type of habitat was not being used by sockeye salmon for spawning. Upstream in the area where spawning was concentrated, the water is faster and more shallow. Observations during the spawning survey indicated that redds were being constructed in less than 2 feet of water with obvious velocity. This corresponds to documented preferred spawning habitat for sockeye in streams. Reiser and Bjornn, (1979) report sockeye salmon preferences for spawning velocities of 4 - 21 feet per second (fps) and depths of ;_>6 inches. Velocities and depths in this range were measured over redds by Chambers et al. (1955. cited in Reiser and Bjornn 1979). These measurements indicated a velocity of 11 fps over each redd with depths from 12 - 18 inches. These values fall within the depth and velocity preference curves developed by the Cedar River Committee Curve Report (Seattle Water Department 1991). In recent years there has been a significant downward trend of the sockeye salmon population. In 1988, the total run size to the Lake Washington/Cedar River basin was the largest on record with an estimated 640,000 adult fish. About 376,000 adults escaped to spawn in the Cedar River that year. Since 1988, escapement to the Cedar has declined dramatically with escapement estimates in the range of 38 percent to 44 percent of the pre-1989 26-year historic average, and with no indications that this trend will change. The 1992 Washington State salmon and steelhead stock inventory (WDFW 1992) listed this population as "depressed". The escapement for 1996 was an exception to this downward trend and was large enough to support a Lake Washington fishing season for sockeye (See Figure 4). Approximately 500,000 adult sockeye returned to the Lake Washington basin during the summer of 1996. A combination of a high fry count entering the lake and excellent ocean feeding conditions is credited with this record run. Over 28 million fry entered the lake from this year class. Whether this is an upward trend is very much open for conjecture. With the exception of this year class, the overall trend is still downward. The 26,000 sockeye escapement in 1995 was the lowest since at least 1970. It is most likely that the 1996 escapement is an aberration common to anadromous fish populations. The escapement goal for the Cedar River is 350,000 adult spawners. 12 Cedar River Sockeye Escapments 500000 400000 r Y iL300000 .. 0 E200000 0 z 100000 1890 1991 1992 1993 1894 1995 1996 Year Figure 4 For the last several years, there have been emergency efforts to ensure that the sockeye salmon run of the Cedar will not drop to critical levels. The emergency measures involve collecting sockeye salmon eggs from captured brood stock in the fall, incubating the eggs to the emergent fry stage, and releasing the newly emerged fry back to the Cedar River in the spring during the normal out- mip ation period. Research to identify the cause of the sockeye decline has recently begun. In 1994, the rrst of several multi -year studies of Lake Washington was initiated to test various hypotheses for the decline. These studies are focused on Lake Washington because the smolt population that rears in the lake has experienced dramatic declines. The Lake Washington basin study program involves financial and/or other resource commitments from many entities such as state and federal agencies, local and county governments, Lake Washington municipalities, tribes, industry, and the University of Washington. Approximately $1.6 million will be spent to support this effort. There are resident cutthroat trout populations in many of the tributaries of the Cedar as well as an adfluvial (migratory lake population) spawning run. Although little is known about anadromous cutthroat trout and Dolly Varden, these species probably use the project area for transportation to higher quality spawning habitat upstream. Juvenile rearing may occur in the project reach, but is very limited. Pfeifer(1993) indicated that there has been a marked increase in spawning cutthroat in Cedar River tributaries in the past few years. With the exception of wild cutthroat trout however, all species of wild anadromous salmonids returning to the entire Lake Washington basin have experienced record low escapement levels since 1989 (Figure 5). Adult chinook enter Lake Washington in June and continue entering through October (See Figure 3). Spawning in the Cedar River occurs from mid -September through mid -December. Intragravel development extends into early March. Chinook rear in the Cedar until fingerling size and out migrate from May through July. No known chinook spawning occurs in or near the project area. 13 Utilization of the project area is primarily for transportation with some possible, although limited, rearing for juveniles. Coho spawning occurs predominantly in the small tributaries of the Cedar River, although some probably occurs in the mainstem, from mid -October through February. Coho rear in the Cedar River one year before migrating out from March through June. Similar to chinook, use of the project area is largely for transportation and limited rearing. The wild winter run of adult steelhead enters Lake Washington between mid -December and mid -May with a peak during late January through early February. Peak spawning in the river can vary from year to year, but generally begins in mid -March and continues into mid -June with a peak during mid - April to mid -May. Spawning of most wild steelhead in the Cedar occurs from RM 1.6 to 21.8 with spawning densities being relatively uniform from RM 5.2 to 21.8. The project area is used by steelhead primarily for transportation, although some limited rearing may occur. A stream -side steelhead culture program using captured wild brood stock provides 40,000 to 80,000 fry that are planted in the Cedar annually. Predation by California sea lions has caused an estimated 50 percent mortality on the returning winter run of Lake Washington bound wild steelhead. Healthy populations of bull trout, a federally listed candidate species, are known to occur in the upper Cedar River watershed above Masonry Dam (RM 35.9). It is unknown whether bull trout reside in the reach between Landsburg Dam (RM 21.8) and Masonry Dam (RM 35.9). A char was recently caught off of the mouth of the Cedar in Lake Washington. This may have been a Dolly Varden or a bull trout. Fluvial populations of bull trout are not uncommon in adjacent drainages. It is possible that bull trout could use the project reach during their spawning migration. However, poor water quality and habitat conditions in the lower river make it unlikely that the project reach is used extensively by bull trout. Longfin smelt are a key species in the Lake Washington fish community and the species which is likely to be affected to the greatest extent by the proposed project. They may compete with juvenile sockeye for the same food resources in the lake (Chigbu and Sibley 1992). This may have contributed to the decline of the sockeye population. Other information shows a concurrent population expansion of longfin smelt and sockeye during the mid 1960s (Edmondson and Abella 1988). This would indicate that at most, the competition causes an indirect effect on population. However, longfin smelt may also serve to buffer predator effects on juvenile sockeye. Longfin smelt have played an important role in the increase in water clarity in the lake (Edmondson and Abella 1988). Daphnia, a small crustacean, eat small particles that make the water cloudy. The major predator on Daphnia was another small crustacean, Neomysis. Neomysis is a major prey species for longfin smelt. When smelt started to increase in abundance, the Daphnia population increased. This caused a corresponding decrease in the particles that caused turbidity in the lake. 14 0 m N r Oh Of r O m m a m r K m 2 ° m Q r A rn } N C 4 m� y O r O m LL � r j n rn m N r D1 r o r m O O O O O O O O O O O O O O O O O O O O O O O O O m Q N O m m Q N 4sld to iogwnN 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O IA O In O � O IA Q fh C'1 N N r r 4sid So iogwnN A O O O N m m r O A C m c O � m m � E CO a O L A U Q r A a o U u W m 0 } N C cc O 7 r a O m o m rn � r m Q m N r n m r O r I I Q) O O O O O O O r O O O O O O O O O O O O O V) O n O [J Cl) N N r r 4sld So jegwnN 0 0 0 0 0 0 0 0 o O o 0 0 0 0 Q r O m m Q N r 4sld Jo isquinN Figure 5. Anadromous Fish Returns to the Lake Washington Basin and Cedar River (adapted from Current and Future Report, Cedar River, King County Surface Water Management, April 1993 and WDFW data, Kurt Fresh 1996) 15 Approximately 98 percent (Sibley and Brocksmith 1996a) of Cedar River longfin smelt spawn within 0.6 kilometers (km) of the mouth of the Cedar River. This is completely within the proposed project reach. The Sibley study found smelt beginning to spawn as early as January 13 in 1993 and as late as May 18 in 1994. Distribution of smelt in the entire Lake Washington basin indicates that the Cedar River is used as the main spawning area. Surveys for smelt in other Lake Washington tributaries were completed in 1970 (Moulton 1970), 1995 (Sibley and Brocksmith 1996a), and 1996 (Martz et al 1996). Results are shown in Table 4. Table 4. Smelt egg distribution in Lake Washington tributaries. Year of Survey May Creek Coal Creek Juanita Creek Denny Creek Swamp Creek Lyon Creek McAleer Creek Thornton Creek 1970 + + + 1995 + + 1996 + + + _ _ _ + _ + indicates presence of eggs, - indicates absence Moulton (1974) observed that these fish exhibited a 2-year life cycle with even -numbered year classes being more abundant and showing a lower growth rate than the odd. He also reported that the Cedar River was the major spawning area and that the larger adults of the odd year -class spawn earlier in the year than the smaller adults of the even year -class. Spawning by longfin smelt takes place in freshwater over sandy -gravel substrates, rocks, and aquatic plants. Most longfin smelt die after spawning but a few live to spawn a second year (McGinnis 1984). The accumulated substrate materials of sand and gravel and relatively wide, weedy, shallow areas of the dredged channel in the lower 1.6 miles of the Cedar River have created good spawning habitat for smelt. Nishimoto (1973) reported that small numbers of peamouth chub spawn in Lake Washington tributaries, although he found no direct evidence of peamouth spawning in the lower Cedar River. Spawning likely occurs from late March through June when mature fish begin to migrate inshore during spring. Spawning peamouth show greater preference for sandy or gravelly substrates. This substrate constitutes most of the bottom materials in the project area. In June and July, Tabor (1996 personal communication) caught numerous peamouth in the lower river during studies in 1995. Presumably these fish were spawning at that time. Largescale suckers also feed or spawn within or near the project reach. They have been observed congregating and spawning upstream of the Logan Avenue bridge. These fish usually move upstream from lakes or impoundments into streams where they seek out gravel riffles with a strong current. Sucker fry and fingerlings serve as important forage for many game fishes. On the other hand, the dense populations of suckers characteristic of many impoundments can be detrimental to the production of some salmonids. Largescale suckers have been observed in the project reach by Service and Corps biologists. 16 Tabor (1996 personal communication) also observed several brook lamprey in the lower Cedar on May 18, 1995. Two pair of these lampreys appeared to be actively spawning. THREATENED AND ENDANGERED SPECIES Bald eagles are known to occur in the vicinity of the project area. Prior to the 1994 dredging, they used the Cedar River delta for foraging (primarily on waterfowl and possibly salmon carcasses). The WDFW reported the occurrence of three adult and two juvenile bald eagles during mid -winter surveys of the Cedar River in 1989. A bald eagle was observed in the Gene Coulan Park area in the southeastern corner of Lake Washington in March of 1992. During October and November in 1991 and 1992, Service biologists observed an occasional bald eagle along the Cedar. In addition, over several weeks of brood stock collection of adult sockeye during October and November in 1991 and 1992, Service biologists observed an occasional bald eagle along the Cedar. An adult bald eagle was observed on September 19, 1995 flying upstream from the mouth of the Cedar River. The nearest known nesting pair of bald eagles occurs about 3 miles from the project at Seward Park on the west shoreline of Lake Washington. The latest species list (USFWS 1996) obtained from the Service for this project was in August 1996. As of that date no listed or proposed species occurred within the project area on a permanent basis. Candidate species that may occur within the project area include the bull trout and the spotted frog. Species of concern include three bat species (long-eared, long-legged, and Pacific western big -eared), Northwestern pond turtles, olive -sided flycatchers and river lamprey. Section 7(a)(2) of the Endangered Species Act of 1973, as amended, requires federal agencies to consult with the Service when a federal action may affect a listed endangered or threatened species. This is to ensure that any action authorized, funded, or carried out by the federal agency is not likely to jeopardize the continued existence of listed species or result in the destruction or adverse modification of critical habitat. A biological assessment was written by the Corps on November 13, 1996. The determination was that this project as proposed is "not likely to adversely affect" any fisted species. The Service wrote a letter of concurrence with that determination on December 11, 1996 through the informal consultation process. If the project or conditions at the site change significantly, the Corps should re -initiate Section 7 consultation through this office. The northwestern pond turtle, Clemmys marmorata marmorata, is a federal species of concern and has been found in Lake Washington historically. It is also listed as endangered by the State of Washington. The WDFW has contracted with a private consultant to survey Lake Washington for northwestern pond turtles (Slavin 1996). To date no northwestern pond turtles have been located. However, only one small area of Lake Washington has been surveyed. The surveyed area is at the Lakewood Marina and is several miles from the Cedar River. The turtles that have been found have been exotics, probably dumped into the lake by pet owners. Surveys during future years may be 17 focused on the Cedar River and south Lake Washington. This will provide additional information about the turtle population of the lake. Service biologists, working on the predator study, observed turtles on several occasions in the project reach of the river. They captured and photographed one of these turtles and tentatively identified it as a red -eared slider, a non-native species that was probably a discarded pet. However, all of the observed turtles were not identified to species. It is possible that there may have been northwestern pond turtles in the project area. STUDY RESULTS Due to the significant fish and wildlife resources at risk, and the gaps in the information on how these resources utilize the project reach, the Service recommended several studies to determine baseline conditions of fish and wildlife resources, evaluate potential impacts, and identify potential mitigation opportunities. In the following section, we will summarize the results of each study. The concerns that were identified during the early scoping for this project primarily focused on the potential impacts on the fishery resources of the Cedar River. The main concern was the potential impacts of the project on spawning habitat and distribution of both sockeye and longfin smelt. Other concerns included predation on sockeye salmon fry, migration delay due to slower water velocity, and effects on macro invertebrates within the project reach. The results in each of these studies are based on very limited data. The Service believes the studies were not extended over a sufficient time span to yield definitive results. At most, three years of data is available and in most cases only two years of data is available. Because of poor weather conditions, problems with equipment, and problems with methods several of the important studies were not completed as designed. The results and conclusions should therefore be used with caution. WILDLIFE STUDY The effect of the project on bird species was the main focus for wildlife studies. Bird surveys were discussed above in the general section on Fish and Wildlife Resources. On February 1, 1996, Corps biologists (Brunner 1996) completed a night avian predator study from the fry trap on the lower Cedar River down to mouth and out into the lake just past the delta. The objective was to provide some quantitative estimate of piscivorous birds that may be drawn to the area due to the emigration of sockeye fry. This date was chosen to coincide with an earlier release of hatchery sockeye fry which should have been reaching the delta at about the same time period as the surveys. Mallards, coots, and gulls were roosting on the logs at the delta and grebes were widely scattered around the lake when the survey began at 1915 hours. Grebes abruptly flew to the mouth just after 2000 hours and were all actively feeding by 2005 hours. This was about 1 hour after the peak fry migration past the fry trap which is about '/g mile upstream from the mouth. By about 2030 the grebes began m dispersing to other parts of the lake. It would be hard not to make some type of connection between the out migrating sockeye fry and the abrupt feeding behavior of the western grebes. Although predation on sockeye smelt is a normal part of the grebes feeding pattern, the migration to the mouth during the out -planting of sockeye fry may have a significant impact on sockeye populations. Additional surveys of this type, coincident with fry releases, should be considered to determine what effects if any western grebes may have on sockeye releases. Other bird species that were feeding in the area, including great blue heron and mergansers, did not alter behavior in any noticeable way during this same time period. Herons were feeding on the delta through this entire time period and were assumed to be feeding on longfin smelt. Mergansers were in the area and were observed actively feeding during this period. Artificial light had been previously assumed to be much greater than normal due to the Boeing plant and the Renton airport, thus providing predators better light conditions for hunting. Although there did seem to be brighter conditions than normal along the river, the light dimmed beyond approximately 100 feet from shore in the lake. This additional light did not seem to be influencing where the birds were feeding. Western grebes have been observed feeding in situations with less light than in the project area. PREDATOR STUDY Potential impacts to sockeye salmon that were identified were mostly focused on increased predation on sockeye fry during their downstream migration and a loss of spawning habitat within the project reach. The first year of predator studies was completed by Service biologists and published in May 1996. The last year of this study was published in November 1996. The 1995 data indicated that the highest density of piscivorous fish and the highest predation rates occur in the lower 600 meters of the Cedar River (Tabor and Chan 1996a). Additional data from 1996 indicated that the vast majority of predation was occurring in the lower 440 meters (Tabor and Chan 1996b). This section is generally backwater from Lake Washington. The only other location where predation of fry was detected was in a backwater eddy near the south Boeing bridge. Prickly sculpin appeared to be the most important predator of sockeye salmon fry because of their abundance, their high consumption rate of fry, and their larger size. Torrent sculpin also had relatively high consumption rates of fry but were less abundant than prickly sculpin. Prickly sculpin have a strong preference for the areas of least velocity and greatest average depth. Several studies (Tabor and Chan 1996b) confirm this preference for lower velocity and deeper water. This type of habitat corresponds significantly with the post project habitat conditions anticipated by the dredging alternatives. In 1995, cutthroat trout seemed to be significant predators as indicated by the highest number of salmonid fry recovered from stomach samples (Tabor and Chan 1996a). Rainbow trout, steelhead smolts, coho salmon, and prickly sculpin also appear to be major predators of salmonid fry in the 19 lower Cedar River. The abundance of predators was relatively small until after the peak fry emigration period. Predation in the littoral zone of southern Lake Washington was low. Cutthroat once again exhibited the highest predation rate. In addition to the predators in the river, smallmouth bass showed up as predators in the lake. In 1996, the salmonid populations in the lower river were significantly lower than the previous year (Tabor and Chan 1996b). This was thought to be due to the flooding earlier in the year. Lonzarich and Quinn (1995, cited in Tabor and Chan 1996a) found that water depth seemed to be more important than structure in determining the distribution of large age 1+ cutthroat and steelhead trout while structure and depth were important for coho salmon smolt distribution. Since cutthroat trout are the main predators in the river, the increase in depth by dredging would seem to favor an increase in cutthroat. Obviously, other factors besides depth enter into the potential for predation. Channel configuration, for example, might increase or decrease predator populations. Information is not available to make this determination. Predation rates appeared to be related to discharge levels. Low predation rates were observed at > 17m3s. Seiler and Kishimoto (1996, cited in Tabor and Chan 1996b) found that survival rates of hatchery sockeye salmon fry were positively correlated with discharge. Survival rates for a discharge of IOm3s would be predicted at around 23 percent, whereas a 17m3s discharge would show a survival rate of around 44 percent. This correlation may be tied to the increased turbidity found during higher discharges. Difficulty with weather, equipment availability and performance limited the population estimates somewhat. However, based on the 1995 data, there did not seem to be obvious movement by predators to the mouth of the Cedar River during the sockeye fry emigration. The number of piscivorous fish did seem to increase after the peak emigration season (May - June). This trend was also seen in the data collected in 1996 (Tabor and Chan 1996b). Therefore any impacts would be concentrated on the late -emerging part of the sockeye population. LONGFTN SMELT STUDY Smelt seem to occupy a "keystone" position in Lake Washington. The population size of the longfin smelt and their interaction with other river and lake species seems to be implicated in water clarity, zooplankton species diversity, competition with sockeye salmon for food resources, and as a prey base for fish predators. Several investigators have looked at the feeding habits and interactions of longfin smelt and sockeye salmon in Lake Washington (Chigbu and Sibley 1992) (Dryfoos 1965) (Edmondson and Abella 1988) (Moulton 1970) (Moulton 1974). Concerns about possible effects to smelt populations include changes in spawning substrate, changes to food sources, and increases or decreases in actual populations. The smelt food base is also a concern as it is related to possible competition with sockeye salmon. An abbreviated study was conducted on Lake Washington for two years that included one high population year and one low population year. Year one of a two year study was completed by Sibley 20 and Brocksmith in April of 1996. The first year study seemed to verify previous reports that indicate that the even year classes are an order of magnitude larger than the odd year classes. Preferred substrate experiments were conducted in artificial streams at the Fisheries Research Institute and Seward Park hatchery. There seemed to be a slight correlation with sand sized particles but the results in this test may have been biased due to the experimental design. Results from field testing showed no apparent correlation with substrate size, water depth or water velocity. Harza (1994) also showed no correlation between particle size, water depth or water velocity. These results are not supported by other studies involving baitfish and substrate preference. Other smelt species have a definite preference for a sand/gravel substrate (Fresh 1996). Longfin smelt in California use a sand/gravel substrate in weedy areas for spawning. Longfin smelt are poor swimmers and seem to avoid high velocities. This may be one of the reasons smelt are found in diminishing numbers above the south Boeing bridge. There also seems to be an inverse correlation to spawning smelt and distance from the mouth of the river. This could be explained by one of several avoidance mechanisms. Larger substrate size, shallower water and higher velocities are found in the reach above Logan Avenue. Smelt may be avoiding any one of or a combination of these habitat components. Another explanation for the decrease in upstream numbers could simply be distance from the lake. Harza (1994) implied this relationship in their report to the Corps. The second year of the two year study was completed by Corps personnel (Martz et al 1996). This study showed a significant negative correlation between egg abundance and substrate size. It also confirmed the negative correlations between egg abundance and velocity and distance upstream found in previous studies. Earlier reports indicated that the "majority" of smelt spawned in the lower Cedar River. Sibley and Brocksmith (1996a) sampled 9 other tributaries in addition to the Cedar River to determine if smelt eggs were present. Eggs were found in May Creek and Coal Creek in very small numbers (See Table 4). The Corps (raw data 1996) found eggs in these two tributaries and additionally in Juanita and McAleer Creeks. Overall 98 percent of the eggs found in the Cedar were in the lower 600 meters (Sibley and Brocksmith 1996a). HABITAT STUDY/SURVEY The second year of a habitat inventory to determine the quantity and quality of salmonid habitat within the project reach has been completed using the State's Timber, Fish and Wildlife methodology (Martz 1996). The percentage of riffle habitat in the lower one mile of Cedar River is quite high, as expected. Around 77 percent is riffle, 2 percent is pool habitat and 20 percent is lake backwater. Pools are largely bank scour pools along the banks near Logan Avenue and the south Boeing bridge. Fine sediment is dominant along the bank areas. Gravel and cobble comprise most of the main channel. This grades into small gravels towards the mouth with deposition of sand and silt during low flow. Armoring occurs during the spring and summer, making many sections of the main channel 21 too hard for sockeye spawning. Overhanging vegetation is found on only 25 percent of the banks, with several 15-20 year old cottonwoods and alders on each side above the south Boeing bridge. Low flow water depth is shallow (<6 inches) in much of the reach between Logan Avenue and the south Boeing bridge. -This often causes the water to heat up significantly with estimates of water temperature > 21 ° C. Warmer water and shallow depths may delay the upstream migration of sockeye adults until the release of flows from the dam in early September. SOCKEYE SALMON SPAWNING SURVEY Two years of spawning surveys have been completed by Corps biologists. Service personnel assisted in two of the surveys during the 1994 and 1995 spawning seasons. Results are summarized in Table 3 for 1994 and 1995. The high water and associated turbidity prevented complete surveys on several days of both seasons but the remaining surveys were completed from the just above the Wells Avenue bridge to the mouth. Combinations of visual wading surveys and snorkel surveys were used to gather data over this entire reach. The majority of the redds were above reference point 15 (1,500 meters) and concentrated along the bank edges. With exception of the December 12, 1995 survey, there were never more than 4 redds downstream of the south Boeing bridge during any survey. Assuming that all redds observed were distinct (with no double -counting between surveys) and had been spawned in, a maximum of 1 percent of the overall sockeye run spawns in the project reach. FISH UTILIZATION STUDIES Daytime and night time snorkeling surveys were conducted to assess fish use of the project reach and related side channels. Corps biologists completed several snorkel surveys from July to September 1995. In the lower mile of the river the only fish observed were rainbow and cutthroat trout, large- scale suckers, mountain whitefish, sculpins, and yellow perch. By the last survey in September, adult sockeye and chinook salmon were appearing in the river. Sculpin and mountain whitefish were the most common. Yellow perch were only observed in the lake backwater and only in small numbers (<10). Crayfish were also observed during the snorkle surveys. An assessment of the impacts of the proposed project on downstream juvenile migration was recommended by the Service. This assessment has not been initiated due to difficulty correlating flows from upstream dams with the City of Seattle. This type of information is still needed to compare the pre- and post -project migration rate for sockeye salmon. Impacts due to increased migration times can not adequately be assessed without this type of information. This should be considered in the mitigation planning for this project. AQUATIC INVERTEBRATE STUDY This study (Sibley and Brocksmith 1996b) was completed in 1996 from field work done in 1995. For the most part, the aquatic invertebrate populations were found in the expected velocity and substrate 22 type. There were some exceptions but these could be explained by sampling size, sampling design, or seasonal variation. Chironomids where the most abundant taxa at all sites during all seasons. They did seem to show less abundance at the lower sites but were still more abundant than other taxa. Ephemeroptera, Plecoptera, and Tricoptera overall were more abundant in the upper reaches in higher velocity water as would be expected. Ohgochaetes were more common in the lower reaches in lower velocity water. There did seem to be a positive correlation between water velocity and both taxa richness and taxa diversity although this correlation was not consistent. This is generally the situation found in other studies. The discussion of effects on the aquatic invertebrates concluded that dredging of the project area would have an extensive effect. A similar project but with a shallower dredge showed that up to 92 percent of the bottom organisms were removed in the dredged area (Rees 1959 cited in Sibley and Brocksmith 1996b). Recovery of all types of insects originally present occurred within 10 months. Macro invertebrate population size may take much longer to rebound. In the Cedar River, the effect due to a deeper proposed dredging will be greater but recolonization should still be fairly rapid. The total impact to the food web in the Cedar River should be minimal due to the 14 miles of assessable anadromous fish habitat above the project area. FUTURE WITHOUT THE PROJECT Based on sediment transport modeling completed by the Corps, the lower Cedar River is aggrading at about 0.2 feet per year measured at the south Boeing bridge. This rate of deposition will fill the channel within 20 years to such an extent that most winter flows will flood the Renton airport and other low lying areas. This deposition of sediment will create a wide very shallow stream with minimal habitat value for fish. Longfin smelt spawning habitat will most likely be severely reduced compared to current conditions. Sockeye spawning habitat may increase in the short term as the higher velocity shallow habitat moves downstream. The quality of this habitat and its length of availability depends on the resultant depth of water and the velocity over the gravel. Armoring of the substrate is likely to occur which would cause any potential spawning gravels to be cemented and too compacted to be usable. Due to the heavy urbanization and industrial base along the project reach, flooding on a yearly basis would cause significant economic hardship. If the Corps would decide not to pursue this project it is likely that other concerned entities would look into alternative solutions to the flooding problem. As the local sponsor for this proposed project, the city of Renton would most likely be involved in other alternatives. 23 POTENTIAL PROJECT IMPACTS TO FISH AND WILDLIFE RESOURCES Under the proposed alternatives, direct project effects on fish and wildlife species and their habitats may be both short-term and long-term. Short term impacts may be on the order of one or two seasons and primarily the result of construction activities. An increase in turbidity and sediment will occur during the actual dredging work. The actual dredging will be limited to between June 15 and August 15. This will minimize the impact on sockeye salmon and other anadromous fish. Depending on the severity of the sediment increase, fish and other aquatic dependent species could be displaced from the project area. Disturbances to the spawning gravels above Logan Avenue could cause scouring of redds during the first winter storms. - It could also cause deposition of sediment on top of these redds. Any impacts on the fish populations in the project reach could cause a ripple effect within the food chain by decreasing the food source or by increased predation on other species within the basin. The sloping of the gradient above Logan Avenue should minimize this effect. But, there may be a significant adjustment of the stream channel during the first winter high flows. These changes may also cause impacts over an extended period. Effects to fish and wildlife resources would vary in magnitude, primarily according to the sensitivity of the species impacted and how important a role it serves in the function of the lake and lower river ecology. Shifts in species distribution and use patterns may be expected from direct habitat modifications, which could cause immediate or long-term ecological changes in the lower river. Long term impacts may result due to permanent habitat losses or degradation. Depending on which alternative is chosen these effects will vary in significance. Each of the "dredge" alternatives and the "no -dredge" alternative have levees associated with them. Short term impacts will be related to sediment from surface erosion on the newly constructed levees and berms. Intensive revegetation should restrict this impact to one season. Long-term aquatic effects from the levees should be minimal as long as best management practices are followed to prevent sedimentation and other disturbances of the stream course. IMPACTS TO WILDLIFE Direct impacts to terrestrial wildlife species and habitats will be largely related to the loss of riparian zone habitat and associated shallow water habitats along both shorelines. Loss of shallow water habitats would directly affect foraging for wading birds such as great blue herons, and feeding dabbling ducks such as mallards. Various gulls may also be displaced as well as fish -eating birds like belted kingfishers, which generally forage in water that is less than 24 inches deep. The loss of existing vegetation could also preclude duck nesting and rearing of duck broods, particularly for mallards and common mergansers, which currently utilize herbaceous and overhanging vegetation for nesting and cover, respectively. The current alternatives minimize streambank disturbance. Plant materials will be salvaged from the left bank and reused as much as possible. This will reduce the impact to the shrub layer but it will still take several years for a dense herbaceous layer to develop. River otter and raccoons are species that often forage among the stream side vegetation or along the irregular and diverse shorelines of streams and creeks. These species could be displaced permanently if riparian vegetation is eliminated or if the project results in decreased diversity in shoreline configuration or a decrease in total edge habitat. With a change to a predominantly silt bottom in the project reach, there will be fewer niches for prey species such as invertebrates and small fish. A change in the prey base may indirectly affect small mammals. The impacts to many of the neotropical bird species may be significant in all of the alternatives due to the construction of levees on the river banks. These levees may eliminate much of the overstory and shrub habitat currently being used for nesting and foraging by birds in the area. This riparian zone habitat can be partially restored over time, but even with immediate revegetation, it will be several decades before the overstory canopy is reestablished. Replanting by using a diverse mix of native species should increase the habitat diversity of the area. A long-term benefit to terrestrial wildlife should be realized due to the increased width of native vegetation along the stream. Removal and control of the non-native invasive plant species adjacent to the river course should enhance this benefit to native wildlife species. IMPACTS TO AQUATIC RESOURCES No Action There is no dredging in this alternative and it should not change sockeye or longfin smelt spawning habitat in the near term. However, with the continual deposition of sediment in this reach, spawning may be precluded due to a lack of suitable habitat in the future. Sediment modeling done by the Corps indicates that within 20 years, the lower reach will be so aggraded that most winter flows will flood adjacent low-lying land. Within the Cedar River channel this may create more spawning habitat for sockeye salmon if depths and velocities are within the preferred parameters. Longfin smelt habitat may be reduced if preferred habitat parameters are lost. Alternative 1 - Levee construction and maintenance dredging only. There is minimal dredging with this alternative. Dredging will be only to create a uniform channel to the depth of the present thalweg. Sockeye or longfin smelt spawning habitat should not be significantly changed except for some minor channel adjustment which could degrade habitat somewhat. Predation on sockeye fry should not increase significantly with this alternative. Also the impacts on aquatic invertebrates should be minor. 25 Alternative 2 - Shallow Dredging (_< 4) The Service's preferred alternative. We believe that this alternative best protects fish and wildlife resources while still providing flood protection for the lower Cedar River corridor. The known impacts have been avoided or mitigated as much as possible. Detailed mitigation plans have yet to be finalized but the Corps seems willing to work cooperatively with the resource agencies to reach final resolution. The dredging will slope the bottom gradient to meet the present gradient about 400 yards above Logan Avenue. In this alternative, the potential spawning area for at least 90 pairs of sockeye salmon will be disturbed (see Table 3). Most of this spawning habitat should be available after the dredging but may be affected due to the adjustment of the stream channel during the first winter high flows. With less depth to the dredging the gravel deposition in the lower reach should begin providing some minimal sockeye spawning after the first major winter storm. Other concerns within the dredged area include the potential for increased predation on sockeye fry as they migrate downstream to the lake. The slower velocities resulting from this shallow dredging will increase the time needed for the fry to move through the project area and will make them more vulnerable to predation. Tabor and Chan (1996) documented several fish species that preyed on sockeye fry during the outmigration period. Assuming that longfin smelt actually have a preference for lower velocity as implied in the smelt studies, then this alternative should increase available smelt spawning habitat. The first year after dredging the habitat may have reduced value for smelt spawning due to channel readjustment. The actual impact of this is unknown. Also it is expected that finer sediment may settle out below Logan Avenue and create a sand and mud substrate. Winter flows should flush this finer material out but with the increased depth of the channel, velocity will be slower. This may prevent this flushing action and reduce the success of smelt spawning. Aquatic invertebrates make up one of the major food sources for fish within the project reach. This shallow dredge option will change the velocity and substrate that largely determine the invertebrate populations. The dredging process will displace or kill most of the resident invertebrates and will cause a zone depauperate of aquatic invertebrates for several weeks to months depending on the species and the specific rate of recolonization. Species which prefer faster, more turbulent water such as mayflies, stoneflies and caddisflies will be eliminated or greatly reduced. Recolonization by these species may be delayed until velocity and substrate within the project reach return to pre -disturbance level. In order to maintain flood control under this alternative, dredging will be more frequent and it is unlikely that habitat for these macro invertebrates will be replaced to the same extent as present. On the other hand, species that prefer slow velocity and fine substrate material, such as oligochaets and most chironomids, should increase due to the increase in available habitat. Initially this group of invertebrates will also be eliminated or reduced because of the dredging operation. Recolonization should occur, assuming that these species exist upstream of the project area. FM Alternative 3 - Moderate Dredging (6). The moderate dredging depths proposed in alternative 3 may significantly change habitat values. The impacts will be similar to those in alternative 2 but will vary in severity depending on the species group under discussion. The moderate dredging up to the south Boeing bridge will create the potential for greater movement of the channel after the first major winter storm events. This may reduce habitat values for sockeye in the project reach. Deeper water will reduce velocities and subsequently the substrate size. This will reduce the suitability of the habitat for sockeye spawning. The effect on sockeye spawning will be greater and will last longer. Gravel movement into the area will be gradual (depending on yearly high flows) and will take several years to approach pre -project levels. The even slower velocities expected with this alternative will increase the time the sockeye fry are exposed to predation in the lower river and may decrease the number entering the lake compared to pre -project levels. This alternative may create habitat more suitable for longfin smelt. The backwater, low velocity areas preferred by the smelt for spawning should increase under this alternative. Effects to aquatic invertebrates will be much like those in alternative 2. The recolonization of the area by mayflies, stoneflies and caddisflies will take longer. Oligochaets and most chironomids should increase due to the increase in available habitat. Alternative 4 The deep dredging with this alternative has the potential for significant impacts to all species and could affect habitat values even outside the immediate project area. The Corps' assessment of this alternative indicates that the deep dredging would increase the rate of deposition and could cause dredging to be necessary even more frequently than in alternatives 2 and 3. Edmondson and Abella (1988) suggested that the increase in the longfin smelt population might have been related to the cessation of dredging in the Cedar River. This was based on historic deep dredging that exceeded 10 feet in depth, in contrast to alternatives 2 and 3, which would dredge to a more moderate depth. Since the majority of the Lake Washington longfin smelt population spawn within the project reach, the change in spawning habitat conditions caused by dredging may be so profound that it could eliminate longfin smelt from any further spawning within the reach. Spawning and egg incubation habitat could degrade significantly because the reach would change from a relatively shallow bed profile to a lake backwater. Substrate material would change from predominantly gravels and cobbles to primarily silts. Channel configuration and surface area would become more uniform. Water temperatures and dissolved oxygen levels would decrease and flows within the reach would decrease in mean velocities. How longfin smelt would respond to these changes is unknown. They may compensate by moving further upstream in the Cedar into better spawning habitat, if available, or expand to other Lake 27 Washington tributaries. It is also possible that smelt may increase beach spawning to a greater degree than now exists. Nevertheless, the smelt population is considered a key, and perhaps the most important, fish species in the Lake Washington ecosystem. Should this population decline or expand dramatically, the cascading effects on the dynamics of the Lake Washington fish community and lake ecology could be highly disruptive. RECOMMENDATIONS During coordination with other resource agencies, there have been concerns raised about constructing this project at this time, given the current sensitivity of the Lake Washington/Cedar River system. Significant efforts are underway to understand why the changes in the ecosystem are occurring. Serious declines in sockeye salmon and steelhead are being observed in the Lake Washington ecosystem. This project, which may have significant effects on the fish community, could be untimely and damaging. The newest alternatives being considered have much less impact on fish and wildlife resources than the historic deep dredging projects. In discussions with the Corps, we have been encouraged by their willingness to protect and mitigate for potential fishery habitat loss with this project. We welcome the opportunity to work with the Corps and the local sponsor to plan the mitigation and any enhancement projects connected with the lower Cedar River flood control project. The mitigation measures recommended by the Service for wildlife have been accepted and incorporated into the latest alternatives. Mitigation will be required for natural resource losses resulting from project implementation. Opportunities to enhance the values of the existing habitat beyond those that currently exist should also be identified pursuant to the Fish and Wildlife Coordination Act. Mitigation involves a series of actions (National Environmental Policy Act, as amended, 42 U.S.C., 4321 et. seq.). These include the following: Avoiding the effect all together; 2. Minimizing the effect; 3. Rectifying the effect; 4. Reducing or eliminating the effect over time; and, 5. Compensating for the effect. The availability, extent, location, and uniqueness of a habitat dictates its value to its constituent fish and wildlife populations. The goal of mitigation ranges from no loss of in -kind habitat values to minimal loss of habitat value. : Habitat for terrestrial species has been severely reduced due to the heavy industrialization of the area, parking lots, and manicured parks. Some species, however, can maintain populations in these conditions. There are currently many bird species using the area for breeding and rearing young. The aquatic habitat has also been significantly altered by human activity. The existing habitat within the project reach provides spawning for a significant number of sockeye salmon and a substantial portion of the longfin smelt population of Lake Washington. The Service has determined that the project could result in adverse effects on existing habitat values. The degree of impact would depend on the alternative that is selected. The Service offers the following recommendations to help the Corps in project planning and to protect, mitigate, and enhance fish and wildlife resources in the project vicinity. These recommendations are based on current project alternatives as furnished by the Corps. The Corps should develop a comprehensive mitigation plan in conjunction with State and Federal agencies and the Tribes. This plan should include actions that avoid or minimize potential impacts to fish and wildlife resources. It should include elements to address longfin smelt, sockeye salmon, and wildlife species. Short-term and long-term monitoring of these resource should also be included. A contingency plan should be developed and implemented if the results of the monitoring show unacceptable impacts. The Corps could provide appropriate funding and participate in the on -going Lake Washington basin studies that deal with sockeye and longfin smelt. MITIGATION FOR WILDLIFE IMPACTS 1. Due to the high value of the riparian zone we recommend that this type of habitat be replaced. Most bird species were observed using the narrow strip of shrub and tree vegetation on the right bank. Tree and shrub planting for overstory cover should be pursued. Plant large sized trees and shrubs to reduce recovery time. Retain all native tree species along the bank where possible and only remove non-native invasive shrub vegetation. Fast growing trees such as native black cottonwood and alders are recommended for the bulk of the plantings. Native conifers such as Douglas fir, western red cedar and hemlock should also be planted to help block light from Boeing at night and to provide a long term vertical habitat component for bird species. 2. The levees, as proposed, will incorporate existing "islands" of higher elevation ground and tie into these areas to create a continuous levee. Using these high points in the park as part of the levee designs may increase the riparian zone diversity and width along the lower river. We highly endorse this concept as well as leaving all trees along the banks and only removing non-native shrubs. 3. Revegetation of disturbed areas should be completed immediately after construction. A plan should be developed to monitor the success of these efforts. Creation of a terrace or shelf associated with the new shoreline to provide shallow water habitat for fish and wildlife -should be investigated. Planting of native emergent submergent marsh plants in the newly created shallow water habitat should be explored. Care should be taken to avoid the invasion of Eurasian watermilfoil, particularly during construction. It is vital to identify new colonies early in order to eradicate it. We recommend an extended monitoring program in the area following construction to ensure watermilfoil is controlled. 4. Due to the sighting of turtles in the project reach, we recommend that turtle surveys be conducted to determine species. Species identification is important because one of the two native turtle species that may occur in this location, the northwestern pond turtle, is a species of concern to the Service. PROPOSED MITIGATION FOR AQUATIC RESOURCE IMPACTS 1. If a dredging alternative is chosen, a monitoring program should be developed to test the assumptions concerning habitat. Smelt could be monitored by looking at the resulting substrate composition during the spawning run, looking at actual use in the dredged area for spawning and by checking egg viability. Sockeye could be monitored by marking a representative number of redds above the test site and looking at depositional rates, or scour depth at each redd site. Potential head -cutting and channel configuration changes should also be monitored after several significant storm events. 2. If this monitoring produces unacceptable results, we recommend that the Corps reconsider the proposed three year dredging cycle. The Service believes that the precarious situation of salmon and steelhead resources in the Lake Washington/Cedar River basin and the potential of the proposed project to adversely affect these resources warrants a cautious approach. Close monitoring as described above could provide early detection of potential fish resource problems and possibly avoid catastrophic results to the fish community in this system. 3. Before dredging, sediments should be tested for contaminants and a determination of whether disturbance of any contaminants found could be toxic to fish and wildlife resources. We are concerned about the possible presence of contaminants due -to the close proximity of two major industrial sites, and the heavy use of fuel, oil, solvents, and other chemicals. Contaminated sediments should be isolated and. stored away from water, particularly rivers, creeks, and lakes. All new concrete structures should be sealed during construction to contain runoff from the construction site until the concrete is fully cured. Runoff should be collected and pumped to a settling basin or other treatment area to remove contaminants before discharge into the Cedar River or other surface water course. Fuels, oils, solvents, and other potentially toxic chemicals should be properly stored and protected from accidental release into the river or lake. 4. Construction activities should take place between mid -June and mid -August. This timing is necessary to miss most of the major fish migrations and minimize project impacts on this part of the life cycle. 5. We recommend that gravel removal be accomplished by dewatering the stream as much as possible and constructing coffer dams to exclude water flow. The actual removal can then be completed in an area isolated from flowing water and should reduce the entry of fine sediment and additional turbidity into Cedar River and downstream into Lake Washington. The actual method could be dragline or front end loader. We recommend using the method that creates the least disturbance to the terrestrial habitat while still protecting the stream. 6. A detailed sediment and erosion control plan should be developed to protect water quality in the project area during and following construction. All steps should be taken to minimize turbidity and fine sediments from entering the river and lake. Sediment retention structures, settling ponds, silt fences, or other measures to protect water quality should be employed as needed during construction. 7. At the spoil disposal site, we recommend that a catch basin be constructed to contain all runoff and prevent sediment from moving downslope into nearby rivers, or other water bodies. The spoils should be covered during the rainy season to reduce erosion and additional downstream sedimentation. Revegetation should be started as soon as practical to provide long term erosion and sediment control. 8. Gravel and cobble removed from the lower river could be cleaned and stored for future fish enhancement projects. These substrate materials may be appropriate in some cases for restoration of fish habitat in upstream areas. This possibility should be investigated. 9. We recommend the Corps investigate onsite mitigation measures for fish impacts. Development of off -channel or side -channel habitat for longfin smelt spawning or salmonid spawning and rearing habitat within the project reach may be possible. Because the existing channel is narrowly confined by development, the opportunities to widen the channel or add additional fish habitat features appear to be limited mostly to the lower river. Any fish habitat features developed for mitigation should be monitored to determine their effectiveness. 10. We recommend the Corps explore the potential for off -site fish mitigation measures similar to an investigation of on -site mitigation opportunities. There may be potential fish mitigation/enhancement projects upstream of the project that are feasible to pursue. We recommend that the Corps coordinate with King County Surface Water Management Division who may have identified potential fish habitat restoration projects in the lower Cedar River basin. A combination of on -site and off -site mitigation projects may adequately serve to offset fish habitat losses. 11. The WDFW presently operates a fry trap near the mouth of the Cedar River. This project as proposed would make this trap unusable and would jeopardize several years of data in a long term study involving the Cedar River. For this reason we recommend 31 that a new location for a fry trap be found in cooperation with WDFW. This trap will need to be installed at least two years in advance of the implementation of this project. This will allow both traps to be fished for two years and a calibration curve to be established. The Service will remain involved in this project and will be available for advice and support as needed. We intend to assist the Corps in the development of the mitigation and monitoring plans for this project and expect that other appropriate resource agencies and the Muckleshoot Tribe will also be involved. 32 LITERATURE CITED Andelman S. and A. Stock. 1993. Management, Research and Monitoring Priorities for the Conservation of Neotropical Migratory Birds that Breed in Washington. Preliminary Assessment and Working Document. Washington Natural Heritage Program. Washington Department of Natural Resources. Olympia, WA. 25 pp. Brunner, K. 1995. Memorandum for the Record. Corps of Engineers. Seattle District Seattle Washington. 3 pp. Brunner, K. 1996. Memorandum for the Record. Corps of Engineers. Seattle District Seattle Washington. 5 pp. Chambers, J.S. G.H. Allen, and R.T. Pressey. Grounds in Natural Areas. Unpublished report WA 1955. Research Relating to Study of Spawning Washington Department of Fisheries. Olympia, Chigbu, P. and T. H. Sibley. 1992. Diet of Juvenile Sockeye Salmon (Oncorhynchus nerka) following changes in the zooplankton composition in Lake Washington. University of Washington. Seattle. (WH-10). unpublished Dryfoos, R.L. 1965. The Life History and Ecology of the Longfin Smelt in Lake Washington. Ph.D. Dissertation. University of Washington. 229 pp. Edmondson, W.T. and S.B. Abella. 1988. Unplanned Biomanipulation in Lake Washington. Limologica 19(1) 73-79. Fresh, K. 1996. Personal Communication. Washington Department of Fish and Wildlife. Olympia WA Hart, J.L. 1973. Pacific Fishes of Canada. Fisheries Research Board of Canada, Bulletin 180, Ottawa. 740 pp. Harza Northwest Inc. 1993. Cedar River Delta Bird Surveys. Report to City of Renton. 23 pp. Harza Northwest Inc. 1994. Distribution of Longfin Smelt (Spirinchus thaleichthys) Eggs in the Cedar River, Washington. Report to City of Renton. 11 pp. Harza Northwest Inc. 1996. Cedar River Delta Project, Final Bird Survey Report. Report to City of Renton. 16 pp. King County. 1993. Cedar River Current and Future Conditions Report. King County Department of Public Works and Cedar River Watershed Management Committee. Seattle, WA. April. 33 Lonzarich, D.G. and T.P. Quinn. 1995. Experimental Evidence for the Effect of Depth andStructure on the Distribution, Growth, and Survival of Stream Fishes. Canadian Journal of Zoology 73 : 2223 -223 0. Martz, M. Jeff Dillon. and Paulinus Chigbu. 1996. 1996 Longfin smelt (Spirinchus thaleichthys) Spawning Survey in the Cedar River and Four Lake Washington Tributaries. U.S. Corps of Engineers, Seattle District. Department of the Army. October, 1996. 21 pp. Martz, M. 1996. Memorandum For the Record. Seattle District Corps of Engineer. Department of the Army. July 15, 1996. 11 pp. McGinnis, S. 1984. Freshwater Fishes of California. Univ. California Press, Berkeley, California. 316pp. Morton, E.S. and R. Greenberg. 1989. The Outlook for Migratory Songbirds: "Future Shock" for Birders. American Birds. Spring. Moulton, L.L 1970. The Longfin Smelt Spawning Run in Lake Washington with Notes on Egg Development and Changes in the Population since 1964. M. S. Thesis, University of Washington. 84 pp. Moulton, L. 1974. Abundance, Growth, and Spawning of the Longfin Smelt in Lake Washington. Trans. Amer. Fish. S oc. 103 (1) 46-52. Nishimoto, M.L. 1973. Life history of the peamouth (Mylocheilus caurinus) in Lake Washington. M.S. Thesis. University of Washington. Seattle, Washington. Pfeifer, B. 1993. Comment Letter on Draft Outline for Lake Washington Basin Salmonid Restoration Plan. State of Washington. Department of Wildlife. Mill Creek. 4pp. Rees, W.H. 1959. Effects of Stream Dredging on Young Silver Salmon and Bottom Fauna. Washington Department of Fisheries. Annual Report. 2:52-65. Reiser, D.W., and T.C. Bjornn. 1979. Habitat Requirements of Anadromous Salmonids. in: Meehan, W.R., ed. Influences of Forest and Rangeland Management on Salmonid Fishes and Their Habitats. General Technical Report PNW-96. U.S.D.A. Forest Service. 54 pp. Seattle Water Department. 1991. Final Report, Cedar River instream flow and salmonid habitat utilization study. Prepared by Cascades Environmental Services, Inc. Seiler, D. and L.E. Kishimoto. 1996. 1995 Cedar River sockeye salmon fry production program. Annual Report, Washington Department of Fish and Wildlife, Olympia 34 Sibley, T.H. and R Brocksmith. 1996a. Lower Cedar River Section 205 Study Longfin Smelt Study Final Report - Contract DACW67-95-M0412. Fisheries Research Institute. University of Washington. Seattle, WA. April, 1996. 50 pp. Sibley, T.H. and R. Brocksmith. 1996b. Lower Cedar River Section 205 Study Aquatic Invertebrate Study Final Report. Fisheries Research Institute. University of Washington. Seattle, WA. May, 1996. 25 pp. Slavin, K. 1996. Letter to U.S. Fish and Wildlife Service. Seattle, WA. September 23. 1996. 1 pp. Stober, O.J. 1975. Cedar River Sockeye Spawning Study. An unpublished report prepared for the Seattle Water Department, Seattle, Washington. Stober O.J. and J.P. Greybill. 1974. Effects of Discharge in the Cedar River on Sockeye Salmon Spawning Area. Univ. of Washington Fisheries Res. Inst., Seattle, Washington. Tabor, R. and J. Chan. 1996a. Predation on Sockeye Salmon Fry by Piscivorous Fishes in the Lower Cedar River and Southern Lake Washington. U.S. Fish and Wildlife Service, Western Washington Office, Olympia, WA. 58 pp. Tabor, R. and J. Chan. 1996b. Predation on Sockeye Salmon Fry by Cottids and other Predatory Fishes in the Lower Cedar River, 1996. U.S. Fish and Wildlife Service, Western Washington Office, Olympia, WA. 48 pp. U. S. Corps of Engineer. 1993. Public Notice of Application for Permit. Permit 4 93-2-00375. City of Renton, Applicant. Seattle, WA. May, 11, 1993. 3 pp. U. S. Fish and Wildlife Service. 1995. Planning Aid Letter to Corps of Engineers. U.S. Department of the Interior. Fish and Wildlife Service. Western Washington Office. Olympia, WA. October 1995. 32 pp. U. S. Fish and Wildlife Service. 1996. Letter to Corps of Engineers. Species list for Federally listed Threatened, Endangered, and Candidate species and species of concern. U. S. Department of the Interior. Fish and Wildlife Service. Western Washington Office. Olympia, WA. August 1996. 2 pp. Washington Department of Fisheries and Wildlife and Western Washington Treaty Indian Tribes. 1992. 1992 Washington state salmon and steelhead stock inventory. 212 pp. Wydoski, R S. and R.R. Whitney. 1979. Inland Fishes of Washington. University Washington Press, Seattle and London. 220 pp. 35 CEDAR RIVER SECTION 205 FLOOD DAMAGE REDUCTION STUDY Detailed Project Report/Final Environmental Impact Statement USFWS Fish and Wildlife Coordination Act Report (February 1997) Recommendation Disposition. 1. Due to the high value of the riparian zone we recommend that this type of habitat be replaced. Most bird species were observed using the narrow strip of shrub and tree vegetation on the right bank [upstream of the south Boeing bridge]. Tree and shrub planting for overstory cover should be pursued. Plant large sized trees and shrubs to reduce recovery time. Retain all native tree species along the bank where possible and only remove non-native invasive shrub vegetation. Fast growing trees such as native black cottonwood and alders are recommended for the bulk of the plantings. Native conifers such as Douglas fir, western red cedar and hemlock should also be planted to help block light from Boeing at night and to provide a long term vertical habitat component :.for bird.species......................................................... ........ ........................ i 2. The levees, as proposed, will incorporate existing "islands" of higher elevation ground and tie into these areas to create a continuous levee. Using these high points in the park as part of the levee designs may increase the riparian zone diversity and width along the lower river. We highly endorse this concept as well as leaving all trees along the banks and only removing non .native shrubs. ................ 3. Revegetation of disturbed areas should be completed immediately after construction. A plan should be developed to monitor the success of these efforts. Creation of a terrace or shelf associated with the new shoreline to provide shallow water habitat for fish and wildlife should be investigated. Planting of native emergent submergent marsh plants in the newly created shallow water habitat should be explored. Care should be taken to avoid the invasion of Eurasian watermilfoil, particularly during construction. It is vital to identify new colonies early in order to eradicate them. We recommend an extended Corps, ResRonses: ...................................................: Partially concur. The riparian zone will not be disturbed except as absolutely necessary for '•. construction of floodwalls on the left bank. This vegetation will be salvaged, as feasible, and replanted on the right bank. The mitigation section describes how the lower portion of the right bank will be vegetated with native plants, including several tree species. The local sponsor has concerns about the safety of using cottonwood trees in the park, so it is likely Oregon ash and alders will be used instead. Conifers will be used. Concur. This recommendation will be followed to the maximum extent feasible. Partially concur. Disturbed areas will be revegetated in the fall season immediately after all construction is complete. The creation of a shallow water terrace will not be possible without placing significant quantities of riprap in the channel to maintain the terrace. Sediment is eroded or deposited from the project reach in such large quantities that a terrace would be extremely difficult to maintain. Monitoring will be conducted to assess terrestrial and aquatic vegetation, particularly Eurasian watermilfoil. monitoring program in the area following construction to ensure watermilfoil is controlled. ...................................................................................................................................... . 4. Due to the sighting of turtles in the project Concur. A turtle survey is currently being reach, we recommend that turtle surveys be conducted. To date, no northwestern pond conducted to determine species. Species turtles have been observed. The final EIS identification is important because one of the :addresses pond turtles and the Corps has two native turtle species that may occur in this determined that the proposed project will not location, the northwestern pond turtle, is a affect pond turtles, even if they do occur in the species of concern to the Service. project area. - ---------------------------------------------------------- 5. If a dredging alternative is chosen, a monitoring program should be developed to test the assumptions concerning habitat. Smelt could be monitored by looking at the resulting substrate composition during the spawning run, looking at actual use in the dredged area for spawning and by checking egg viability. Sockeye could be monitored by marking a representative number of redds above the test site and looking at depositional rates, or scour depth at each redd site. Potential head -cutting and channel configuration changes should also be monitored after several significant storm events. 6. If this monitoring produces unacceptable results, we recommend that the Corps reconsider the proposed three year dredging cycle. The Service believes that the ':. precarious situation of salmon and steelhead resources in the Lake Washington/Cedar River basin and the potential of the proposed project to adversely affect these resources warrants a cautious approach. Close monitoring as described above could provide early detection of potential fish resource problems and possibly avoid catastrophic results to the fish community in this system: ............................................................................................ 7. Before dredging, sediments should be tested for contaminants and a determination of whether disturbance of any contaminants found could be toxic to fish and wildlife resources. We are concerned about the possible presence of contaminants due to the close proximity of two major industrial sites, and the heavy use of fuel, oil, solvents, and other chemicals. Contaminated sediments s should be isolated -and stored away from water, particularly rivers, creeks, and lakes. _.__------------------ Partially concur. Monitoring for the preferred alternative is described in the final EIS. Smelt spawning habitat will be monitored, as will sockeye spawning in the project area and mitigation site to ensure that all assumptions made prior to construction are indeed valid. Surveys will be conducted each year, which will show if head -cutting is occurring. Future maintenance dredging will be designed to avoid head -cutting based on survey results. Partially concur. The Corps will monitor the project to ensure that all anticipated impacts are adequately mitigated for, as well as to ensure that no unforeseen impacts are occurring. If monitoring shows unacceptable results, the Corps will engage in contingency actions which may involve new mitigation or a reduced frequency of dredging. However, the purpose of the project is to provide 100 year flood protection in Renton. Any reduced frequency of dredging must ensure that Renton is fully protected from flooding. Concur. The sediments will be tested before construction to ensure they are clean and fit € for upland or in -water disposal. Based on past testing (and the significant presence of sand and gravels), there is no reason to believe the sediment is contaminated. During construction, the new concrete pier structures for the south Boeing bridge will be isolated from the river with coffer dams and any water that percolates inside the coffers dams will be pumped to a holding area. All new concrete structures should be sealed during construction to contain runoff from the construction site until the concrete is fully cured. Runoff should be collected and pumped to a settling basin or other treatment area to remove contaminants before discharge into the Cedar River or other surface water course. Fuels, oils, solvents, and other potentially toxic chemicals should € be properly stored and protected from accidental release into the river or lake. ...........................................................................................................................:.......................................................................................................................... 8. Construction activities should take place Concur. The in -water construction window will between mid -June and mid -August. This be June 15-August 31. timing is necessary to miss most of the major fish migrations and minimize project impacts on this part of the life cycle: _............... ....... 9. We recommend that gravel removal be Partially concur. In areas upstream of the accomplished by dewatering the stream as € south Boeing bridge, cofferdams will be used much as possible and constructing coffer € to divert the river away from the dredging site dams to exclude water flow. The actual to prevent turbidity increases in the river and removal can then be completed in an area lake. Below the south Boeing bridge this will isolated from flowing water and should reduce not be possible due to the lake backwater that the entry of fine sediment and additional '•, backs up water up to 8 feet deep across the turbidity into the Cedar River and downstream entire channel. In this area, a clamshell, into Lake Washington. The actual method dragline or hydraulic suction dredge may be could be dragline or front end loader. We used. recommend using the method that creates the least disturbance to the terrestrial habitat while still protecting the stream. ......... ....................................................:................................................................................. 10. A detailed sediment and erosion control plan should be developed to protect water quality in the project area during and following construction. All steps should be taken to minimize turbidity and fine sediments from entering the river and lake. Sediment retention structures, settling ponds, silt fences, or other measure to protect water s quality should be employed as needed during construction. _........................................................................................................................ 11. At the spoil disposal site, we recommend that a catch basin be constructed to contain all runoff and prevent sediment from moving downslope into nearby rivers, or other water bodies. The spoils should be covered during the rainy season to reduce erosion and additional downstream sedimentation. Revegetation should be started as soon as s practical to provide long term erosion and sediment control :......................................................................................................................... Concur. The Corps and the City of Renton will develop an erosion control plan during plans and specifications, and during coordination with the Department of Ecology for the Water Quality Certification. Concur. During plans and specifications, the dredged material disposal plans will contain these and other best management practices to avoid returning turbid (or otherwise contaminated water) to the river and lake. .......................................................................................................................................................................................................................................................: 12. Gravel and cobble removed from the Partially concur. The local sponsor will be lower river could be cleaned and stored for responsible for disposal and storage of the future fish enhancement projects. These ` dredged material. The Corps has substrate materials may be appropriate in recommended that interested agencies and some cases for restoration of fish habitat in tribes request the use of some of the material upstream areas. This possibility should be for fish enhancement projects upstream. investigated: ........................................................................:........................................................................................................................... 13. We recommend the Corps investigate Do not concur. The Corps investigated the onsite mitigation measures for fish impacts. ' potential for on -site mitigation for this Development of off -channel or side -channel proposed project. The high sedimentation habitat for longfin smelt spawning or salmonid rate and limited space appear to make an on - spawning and rearing habitat within the site channel or side -channel ineffective. The project reach may be possible. Because the Corps has proposed an off -site mitigation site I existing channel is narrowly confined by € for spawning and rearing habitat. On -site, development, the opportunities to widen the riparian plantings will be provided for channel or add additional fish habitat features compensation for impacts to aquatic appear to be limited mostly to the lower river. ' invertebrates and salmon holding and rearing. Any fish habitat features developed for mitigation should be monitored to determine their effectiveness. ...........................................................................................................................:........................................................._.................................................................: 14. We recommend the Corps explore the Concur. See response above to potential for off -site fish mitigation measures recommendation #13. similar to an investigation of on -site mitigation opportunities. There may be potential fish mitigation/enhancement projects upstream to the project that are feasible to pursue. We recommend that the Corps coordinate with King County Surface Water Management Division who may have identified potential fish habitat restoration projects in the lower Cedar River basin. A combination of on -site and off- € site mitigation projects may adequately serve to offset fish habitat losses. .. ................ ............................. .. ...........:.. ... .................._. .. ......... ............. ... ............ 15. The WDFW presently operates a fry trap Partially concur. The Corps is coordinating near the mouth of the Cedar River. This with WDFW to determine a new location for project as proposed would make this trap the fry trap, as well as to determine when unusable and would jeopardize several years WDFW would like the trap moved. To date, of data in a long term study involving the the WDFW has requested that the fry trap be Cedar River. For this reason we recommend moved just prior to construction to a location that a new location for a fry trap be found in upstream of 1-405 (site not yet determined). cooperation with WDFW. This trap will need ' Because the sediment load is so significant in to be installed at least two years in advance of the lower river each year, WDFW recalibrates the implementation of this project. This will ' their trap every year. Therefore, it is not allow both traps to be fished for two years and necessary to provide a new trap two years a calibration curve to be established. .......................................................................................................................... prior to construction. ....................................................................................................................... APPENDIX C: DISTRIBUTION FOR DRAFT EIS AND PUBLIC WORKSHOP ATTENDANCE LIST Adam Smith U.S. House of Representatives 3600 Port of Tacoma Road, E., Suite 308 Tacoma, WA 98424 Allan Newbill Town of Hunt's Point 3000 Hunts Point Road Hunts Point, WA 98004 Anmarco 9125 10th Avenue, S. Seattle, WA 98108 August Tonell 20916 Military Road, S. Seattle, WA 98188 Advisory Council on Historic Preservation Office of Program Review & Education -- -1-100 Pennsylvania_ Ave., NW, #803 Washington, DC 20004 American Legion #19 1308 Beacon Way, S. Renton, WA 98055 Ann Grinolds 324 Cedar Avenue, S. Renton, WA 98057 Baldwin & Dana Vischer 260 Ridge Drive Port Townsend, WA 98368 Belmondo Family Limited Partnership Ben Meyer 5415 Pleasure Point Lane National Marine Fisheries Service Bellevue, WA 98006 525 NE Oregon Street, Suite 500 Portland, OR 97232-2737 Bertha Miller Bill Sikonia 1307 N 32nd USGS Water Resources Division Renton, WA 98056 1201 Pacific Avenue, Suite 600 Tacoma, WA 98402 Bill Wiggins USGS Water Resources Division 1201 Pacific Avenue, Suite 600 Tacoma, WA 98402 Bob Winter WA Dept of Transportation P.O. Box 330310 Seattle, WA 98133-9710 Bradley & Renita Gullstrand 51 Logan Avenue, S. Renton, WA 98055 Caesar Tasca 221 N Williams Street Renton, WA 98055 Cherry Knight -Larson 6827 34th Avenue, NW Seattle, WA 98117 Bob Frietag Federal Emergency Mgmt Agency -140 228th SW Bothell, WA 98021-9796 Bonnie Shorin WA Dept of Ecology P.O. Box 47600 Olympia, WA 98504-7600 Burlington Northern RR Honeywell Center, Suite 290 373 Inverness Drive, S Englewood, CO 80112-5831 Carol Dobson P.o. Box 59 Renton, WA 98057 Chief, Environmental Evaluation Branch US Environmental Protection Agency 1200 6th Avenue Seattle, WA 98101-1931 Chuck Phillips City of Tukwila WDF&W, Interim Regional Director ATTN: Mayor 16018 Mill Creek Blvd. 6200 Southcenter Blvd. Mill Creek, WA 98012 Seattle, WA 98188 Craig & Margaret Simpson Crescent Family Partnership 111 Wells Avenue, N. 7510 Eastside Drive, NE Renton, WA 98055 -Tacoma, WA 98422 - Curt Beardslee Dale Mesecher Washington Trout 913 N 2nd Street P.O. Box 402 Renton, WA 98055 Duvall, WA 98019-0402 Danilo & Gloria Delmundo David Mason 16546 SE 19th St 231 Williams Avenue, N. Bellevue, WA 98008 Renton, WA 98055 David Swanson Dean Bitney 4616 S 124th 2727 Mt. View Avenue, N. Seattle, WA 98178 Renton, WA 98056 Dennis Ossenkop Dino Patas FAA, Airport Division 1815 Rolling Hills Avenue, SE 1601 Lind Avenue, SW Renton, WA 98055 Renton, WA 98055-4056 Director Director US Fish & Wildlife Service, Endangered Species National Marine Fisheries Service 3704 Griffin Lane, SE, Suite 102 7600 Sand Point Way, NE Olympia, WA 98501-2192 Seattle, WA 98115 Director Director, Environmental Review Section Audubon Society WA Dept of Ecology Western Regional Office -P.O. Box 47703 Olympia, WA 98507-0462 Olympia, WA 98504-7703 Don Morrison Donald & Margaret Schumsky 14601 SE 173rd 2019 Jones Avenue, NE Renton, WA 98055 Renton, WA 98055 Douglas & Claudia Buck Edward Gonzalez 904 N Riverside Drive 11015 142nd Avenue, SE Renton, WA 98055 Renton, WA 98056 Edward S. Syrjala Eric Warner P.O. Box 149 Muckleshoot Fisheries Dept. Centerville, MA 02632 40405 Auburn -Enumclaw Road Auburn, WA 98002 Erik Hansen Esell Corporation WA Dept of Transportation 126 Wells Avenue, S. P.O. Box 330310 Renton, WA 98055 Seattle, WA 98133-9710 Eugene A & Christine Frasier Executive Director 778 Ashley Court NW Indian Fisheries Commission Buckley, WA 98321 6730 Martin Way Olympia, WA 98506-5540 Finn Hansen First Federal Savings & Loan 835 North 1st Street P.O. Box 358 Renton, WA 98055 Renton, WA -98055 - Frank Urabeck Gary & Pamela Dime 2409 SW 317th Street 2425 127th Avenue, NE Federal Way, WA 98023 Bellevue, WA 98005 Gary Engman Gary Sund WA Dept of Fish & Wildlife City of Kirkland 16018 Mill Creek Blvd. 123 5th Avenue Mill Creek, WA 98012 Kirkland, WA 98033-6189 Gene Stagner George Schneider US Fish & Wildlife Service Seattle Water Dept, Dexter Horton Bldg. 3704 Griffin Lane, SE 710 Second Avenue, MS 15101 Olympia, WA 98501-2192 Seattle, WA 98104 Gino Lucchetti Glenn Boettcher King County Surface Water Mgmt City of Mercer Island 700 5th Avenue, Suite 2200 9611 SE 36th Street Seattle, WA 98104 Mercer Island, WA 98040 Glenn Boettcher Glenn Reynolds City of Mercer Island 55 Logan Avenue 9611 SE 36th Street Renton, WA 98055 Mercer Island, WA 98040 Grace Storwick & John Giuliani Greg & Deborah Devereaux P.O. Box 78327 909 North 1 st Street Seattle, WA 98178 - Renton, WA 98055 H. Paul Friesema Hadi Fakharzadeh Northwestern Univ., Center for Urban Affairs 11226 Auburn Avenue, S. 2040 Sheridan Road Seattle, WA 98178 Evanston, IL 60208-4100 Highline Times Holly Coccolli ATTN: News Editor Muckleshoot Fisheries Dept. P.O. Box 518 39015 SE 172nd Avenue Burien, WA 98166 Auburn, WA 98002 Honorable Gary Locke Housing Authority Office of the Governor City of Renton Legislative Building, AS-13 200 Mill Avenue, S., City Hall Olympia, WA 98504 Renton, WA 98055 Jaek Davis James & Theresa Zimmerman King County Conservation District 813 North 1st Street 935 Powell Avenue, SW Renton, WA 98055 Renton, WA 98055 James Kirkman Jean Shabro 1002 North 35th c/o Nancy Oertel Renton, WA 98055 1418 El Nido Way Sacramento, CA 95864 Jean White King County Land & Water Mgmt. 700 5th Avenue, Suite 2200 Seattle, WA 98104 John Burkhalter 803 North 1st Street Renton, WA 98055 John Hargrove 105 Wells Avenue, N. Renton, WA 98055 John Malek US Environmental Protection Agency 1200 6th Avenue, WD-128 Seattle, WA 98101-3188 Jonathan Frodge King County METRO 821 2nd Avenue, MS-81 Seattle, WA 98104 Josephine Morrison 112 Wells Avenue, N. Renton, WA 98055 John A. & Carol M. Veness 36 Logan Avenue, S. _Renton, WA 98055 John Gould 806 N 2nd Street Renton, WA 98055 John Lombard King County Surface Water Mgmt. 700 5th Avenue, Suite 2200 Seattle, WA 98104 John Sparrow 908 N Riverside Drive Renton, WA 98055 Joseph Marchetti 801 North 2nd Street Renton, WA 98055 Journal -American ATTN: News Editor P.O. Box 90130 Bellevue, WA 98009 June Dolen 814 N. 2nd #C Renton, WA 98055 Kathy Minsch Puget Sound Water Quality Authority P.O. Box 40900, MS PV-15 Olympia, WA 98504-0900 Kenneth Shellan 591 N Patencio Road Palm Springs, CA 92262 Kevin & Kathy Bruce 921 North 1st Street Renton, WA 98055 Kurt Fresh WA Dept of Fish & Wildlife P.O. Box 43149 Olympia, WA 98504 Lavina Kessler 310 Pelly Avenue, N. Renton, WA 98055 June Evans 817 North 1st Street Renton, WA -98055 Kenneth King 350 Sunset Blvd., N Renton, WA 98055 Kevin & Eugenia Beckstrom 206 Wells Avenue, N. Renton, WA 98055 Kit Paulsen Bellevue Utilities Department P.O. Box 90012 Bellevue, WA 98009-9012 Larry Fisher WA Dept of Fish & Wildlife 22516 SE 64th Place, Bldg. E, Suite 240 Issaquah, WA 98027 Lee York 2200 Aberdeen Avenue, NE Renton, WA 98055 Leonard Leathley, Jr. Louis Peretti 809 N 2nd Street 1102 Bronson Way Renton, WA 98055 Renton, WA 98055 Lynn Childers Marion Lauck US Fish & Wildlife Service 904 North 1st Street 3704 Griffin Lane, SE Renton, WA 98055 Olympia, WA 98501-2192 Marjorie Bellando Mary Ann Leggitt P.O. Box 70217 375 Union Avenue, SE, #115 Bellevue, WA 98007 Renton, WA 98059 Mary Barrett Mary Moroni WA Dept of Natural Resources 202 Burnett Avenue, N. P.O. Box 47027 Renton, WA 98055 Olympia, WA 98504-7027 Mary Patricia Ryan McLendon Hardware, Inc. P.O. Box 336 710 2nd Avenue Renton, WA 98057 Renton, WA 98055 Mehdi Nakhjiri Mike Linnel Boeing Commercial Airplane Group U.S. Department of Agriculture P.O. Box 3707, MS 63-01 720 O'Leary Street, NW Seattle, WA 98124-2207 Olympia, WA 98502 Muckleshoot Indian Tribe Nancy Davidson Tribal Council Seattle Water Department 39015 172nd Avenue, SE __710 Second Ave., MS 15101 Auburn, WA 98002 Seattle, WA 98104 Neal Jensen Norman & Marian Schultz P.O. Box 353 7634 Sunnycrest Road Renton, WA 98057 Seattle, WA 98178 North American Refractories Paul Szewczykowski 500 Halle Building 26226 187th Place, SE 1228 Euclid Avenue Kent, WA 98042 Cleveland, OH 44115 Pete Soverel Peter & Nancy Forras Federation of Fly Fishermen 2030 Rolling Hills Avenue, SE 16430 72nd Avenue, W. Renton, WA 98055 Edmonds, WA 98026-4908 Proteam Marketing Puget Sound Power & Light Co. 514 Auburn Way, N. Property Tax Dept. Auburn, WA 98002 P.O. Box 90868 Bellevue, WA 98009 Ralph Storey Rand Little 1012 N Riverside Drive Seattle Water Department Renton, WA 98055 710 Second Avenue Seattle, WA 98104 Randall Reeves 7050 150th Avenue, NE Redmond, WA 98052 Raymond Barry 1625 Jones Drive, SE Renton, WA 98055 Ren Four, Inc. P.O. Box 59 Renton, WA 98055 Renato & Paz Santos 1815 Lake Youngs Way, SE Renton, WA 98058 Renton School District 403 435 Main Avenue, S. Renton, WA 98055 Representative Eileen Cody 304 John L. O'Brien Office Bldg. Olympia, WA 98504-0600 Randy Aliment 310 Renton Avenue, S -Renton, WA 98055 Regional Director N OAA 7600 Sand Point Way, NE Seattle, WA 98115 Rena McMillan 121 Wells Avenue, N. Renton, WA 98055 Renton Local 1797 Brotherhood Carpenters & Joiners 231 Burnett N. Renton, WA 98055 Representative Dawn Mason 324 John L. O'Brien Office Bldg. Olympia, WA 98504-0600 Representative Ida Ballasiates 431 John L. O'Brien Office Bldg. Olympia, WA 98504-0600 Representative Jack Cairnes 430 John L. O'Brien Office Bldg. Olympia, WA 98504-0600 Representative Kip Tokuda 323 John L. O'Brien Office Bldg. Olympia, WA 98504-0600 Representative Velma Veloria 303 John L. O'Brien Office Bldg. Olympia, WA 98504-0600 Robert & Geraldine Hyler 127 Pelly Avenue, N. Renton, WA 98055 Roger Tabor US Fish & Wildlife Service, 2625 Parkmont Lane, SW, Olympia, WA 98502 Ronald & Jacqueline Forte P.O. Box 816 Renton, WA 98057 Representative Jennifer Dunn 50 116th Avenue SE -.Bellevue, WA 98004 Representative Suzette Cooke 429 John L. O'Brien Office Bldg. Olympia, WA 98504-0600 Richard & Daphne Storwick P.O. Box 78327 Seattle, WA 98178 Roger Davis P.O. Box 452 Renton, WA 98055 Ronald & Colleen Nelson FRO 17221 163rd Place, SE Bldg B Renton, WA 98058 Ruby Heitman 50 Logan Avenue, S. Renton, WA 98055 Rudolph & Beverly Starkovich Russell E. Storwick 810 N Riverside Drive P.O. Box 1083 Renton, WA 98055 Renton, WA 98057 S.L. Routley Sally Abella 918 Riverside Drive University of Washington Renton, WA 98055 Dept of Zoology, NJ-15 Seattle, WA 98195 Sally Fisher Sarah Humphries 854 Redmond Avenue, NE Northwest Rivers Council Renton, WA 98056 1731 Westlake Avenue, N, Suite 202 Seattle, WA 98109-3043 Seattle Shorelines Coalition Seattle Times ATTN: Chairperson ATTN: News Editor 4207 Bagley Avenue, N. P.O. Box 70 Seattle, WA 98103 Seattle, WA 98111 Senator Patty Murray Simon & Hanna Young Jackson Federal Office Bldg 6531 83rd Place, SE 915 2nd Avenue Mercer Island, WA 98040 Seattle, WA 98174 Slade Gorton Slapshot, Inc. United States Senator 999 Third Avenue, Suite 3600 10900 NE 4th Street, Suite 2110 Seattle, WA 98104 Bellevue, WA 98004-5841 Soren & Karen Sorenson 706 North 1st Street Renton, WA 98055 State Senator Margarita Prentice 419 John Cherberg Office Bldg. Olympia, WA 98504-0482 Tennessee Group 710 S. Second Street Renton, WA 98055 Terrence Callahan 210 Burnett Avenue, Renton, WA 98055 State Senator Jim Horn 407 Legislative Office Bldg. Olympia; WA 98504-0460 State Senator Stephen Johnson 401 C Legislative Office Bldg. Olympia, WA 98504-0460 Tennessee Group 11316 85th Avenue, S. Seattle, WA 98178 The Boeing Company N. P.O Box 3707, MS LF-09 Seattle, WA 98124 Thomas Barr & Sophie McHardie 802 High Avenue, S. Renton, WA 98055 Tom Luster WA Dept of Ecology P.O. Box 47703 Olympia, WA 98504-7703 Tim Goon King County METRO 821 Second Avenue, MS-120 Seattle, WA 98104 Tom Sibley University of Washington School of Fisheries, WH-10 Seattle, WA 98195 U.S. Dept of Agriculture Natural Resources Conservation Service 6128 Capitol Blvd., S. Olympia, WA 98501-5271 U.S. Dept of Commerce/NOAA Regional Director 7600 Sand Point Way, NE Seattle, WA 98115 U.S. Dept of the Interior, ATTN: Fish Officer 3006 Colby Avenue Everett, WA 98201 W.E. Bennett C, of Renton 200 Mill Avenue, S. Renton, WA 98055 WA Dept of Ecology Sediment Management P.O. Box 47703 Lacey, WA 98503 Warin Gross 829 North 1st Street Renton, WA 98055 Bureau of Indian Affairs U.S. Dept of Commerce NMFS, Environmental Technical Services --525 NE Oregon, Suite 500 Portland, OR 97232 U.S. Dept of Housing & Urban Development Community Development & Planning 909 1 st Ave, Suite 200, MS 10C Seattle, WA 98104 US Dept of the Interior Bureau of Land Mgmt., State Director P.O. Box 2965 Portland, OR 97208 WA Dept of Commercial Development Office of Archaeology & Historic Preservation P.O. Box 48343 Olympia, WA 98504-8343 Walter Austin & R. McCrimmon 2588 Pacific Hwy, E. Tacoma, WA 98424 Wesley & Lori Holman 129 Wells Avenue, N. Renton, WA 98055 Wilbur Repp 10936 SE 235th Place Kent, WA 98031 William D. Allingham P.O. Box 48117 Seattle, WA 98148 William & Diana Kodad 19212 SE May Valley Road .__Issaquah, WA 98027 Wyman Dobson 821 North 1st Street Renton, WA 98055 CEDAR RIVER SECTION 205 FLOOD DAMAGE REDUCTION STUDY PUBLIC MEETING APRIL 29, 1997 SIGN -IN SHEET ;AAM ADDRESS 0 � /4v t/ G G 3 CS8 �6 \ " 1 0 L,° c1 rf 0 0; E 5 7-- O P ca t5 �o 9 i 7 5 (3 � s 5 A7rc c- wi4 ' •.1CN�i-JL--"S � �I Sv��✓ Sr��G� A-v� S 4 I Z� ylu`( 99I7 B CEDAR RIVER SECTION 205 FLOOD DAMAGE REDUCTION STUDY PUBLIC MEETING APRIL 29, 1997 SIGN -IN SHEET NAME ADDRESS ✓ Lr� Lac i�cr�u�c'7r��f� �� zi2 o 9,y tv� UL 13. C ,v& L A 0 3oX 2 5 -� - Y� 1 �2 �7 AGENDA PUBLIC WORKSiHOP CEDAR RIVER SECTION 205 FLOOD DAMAGE REDUCTION STUDY DRAFT ENVIRONMENTAL IMPACT STATEMENT 6:30 PM Sion -In 6:45 PM Introduction, Purpose of Workshop 6:55 PM City of Renton Intro, Need -for Study 7:00 PM Review of Draft EIS Format Alternatives Evaluated Impacts Identified Mitigation Proposed 7:45 - 8:30 PM Question and Answers, Comment Period 4/30/97 MFR: Cedar River Section 205 Study, Public Meeting on Draft Environmental Impact Statement (DEIS), 4/29/97 A public meeting was held as part of the EIS process the evening of 29 April 1997 at the Renton Community Center, Renton, WA. Merri Martz, ERS, presided over the meeting. Also attending were Linda Smith, CP and Ron Straka and Ross Hathaway from the City of Renton. An agenda, sign in list, and copies of overheads are enclosed (enclosures). The 45 day public comment period for the DEIS ends 9 May 1997. 2. Following a presentation by Merri of the alternatives evaluated for the project, the environmental impacts and proposed mitigation, the meeting was opened for public comment and questions. The comments are summarized as follows: a) Delta. There were a number of questions concerning whether the delta on the Cedar affected flooding, and whether it should be dredged to reduce the number of birds in the area, a potential flight hazard for the Renton airport. We explained that our hydraulic analysis indicates for the preferred alternative, minimal dredging (4'), the delta does not impact flooding, and delta dredging cannot be justified with our flood control study. Under Section 205 authority we cannot dredge for aviation related purposes. Renton dredged the delta in 1993. The delta refilled within one-two years. Immediately after dredging, a bird study commissioned by Renton indicated that the birds merely moved to the river, park and airport tarmac. We did discuss plantings for mitigation along the right bank of the channel, and how we are designing these to discourage the presence of geese and gulls, two species of concern for bird strikes. We will coordinate further with the Department of Agriculture on this issue (they have bird hazard experts). b) Dred- i . Several citizens testified to the rapid fill rate in the channel area, based on their observations of the refill rate when Renton previously dredged to 8-10 feet in the study area (occurred until 1980's). There was some concern whether our project could handle the rapid sedimentation in the area. We responded that our sedimentation studies show that if the channel is regularly maintained every 3-10 years (based on observed refill rates and actual hydraulic/hydrologic conditions) the project will provide at least 100 year flood protection in the project area; in combination with our proposed levee system and modifications to the south Boeing bridge. c) Erosion. Questions were raised whether the current erosion/deposition rate in the basin is worse than it was prior to the 1980s. The historical data for sedimentation in the Cedar is anecdotal and there are no records of what quantities of material was removed from the channel and delta. Early development and logging likely caused erosion, but at the same time the Cedar was being mined (by Stoneway) for gravel near the project area. The Cedar Basin Plan is attempting to limit increased erosion from development in the future, but it is anticipated that erosion will continue to be a problem. The Cedar is in a narrow, steep valley, and does not have the ability to drop much of its bedload until it reaches the artificial channel in the study area. Overall, parts of the upper Cedar may actually be gravel starved. d) Disposal of Dredged Materials. Several citizens wondered if the dredged gravels can be sold. We responded that Renton has a storage site available near the project (Narco site) where gravels can be stockpiled temporarily. Renton noted they plan to either sell the material and/or use it for public projects (i.e. park development). e) Chester Morse Dam. Seattle was complemented by attendees for its ability to reduce flooding impacts since 1990 with their operation of Chester Morse Dam. John Lombard, King County, noted that the County, Renton, and Seattle have jointly sponsored a study to evaluate modifications in the operation of the dam to improve flood control in the future. 3. Additional copies of the DEIS and Draft Detailed Project Report were provided to interested attendees. Comments from the meeting will be addressed in the FEIS. Linda Smith Encls (as) cc w/encls. Smith CP Martz ERS ED-PL File T