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Home My WebLink AboutAppendix Z - Wetland DR I-405, Renton Nickel Improvement Project, I-5 to SR 169 WETLANDS DISCIPLINE REPORT October 2005 %&e( !"b$ AÉ !"`$ !"`$ Aæ %&e( Bothell Kirkland Bellevue Renton AÊ AÐ Aí Aô AÌ Aí Aç AÅ Lake Washington Arterial Road Freeway Municipality Lake Park M0 2 Miles I-405 Project Area Renton Nickel Improvement Project WETLAND DISCIPLINE REPORT I-405, Renton Nickel Improvement Project Prepared for Washington State Department of Transportation Urban Corridors Office And Federal Highway Administration Prepared by Ilon Logan, Adolfson Associates, Inc. October 17, 2005 Title VI WSDOT ensures full compliance with Title VI of the Civil Rights Act of 1964 by prohibiting discrimination against any person on the basis of race, color, national origin or sex in the provision of benefits and services resulting from its federally assisted programs and activities. For questions regarding WSDOT's Title VI Program, you may contact the Department's Title VI Coordinator at 360. 705.7098. Americans with Disabilities Act (ADA) Information If you would like copies of this document in an alternate format—large print, Braille, cassette tape, or on computer disk, please call 360.705.7097. Persons who are deaf or hard of hearing, please call the Washington State Telecommunications Relay Service, or Tele-Braille at 7-1-1, Voice 1.800.833.6384, and ask to be connected to 360.705.7097. Renton Nickel Improvement Project Wetland Discipline Report i T ABLE OF C ONTENTS Glossary...............................................................................................................................................................................iii Acronyms and Abbreviations Used in this Report................................................................................................................v Introduction..........................................................................................................................................................................1 What is the Renton Nickel Improvement Project? ...........................................................................................................1 What is the No Build Alternative?................................................................................................................................2 What is the Build Alternative?.....................................................................................................................................2 How will stormwater from the project be managed? .................................................................................................12 What environmental and utilities issues influenced the project design and what was done to avoid and minimize project effects?....................................................................................................................................13 What is planned for wetland and stream mitigation?.....................................................................................................16 What benefits will the project provide?......................................................................................................................17 How will the project incorporate community design preferences?.............................................................................17 How will the project be constructed?.........................................................................................................................18 Why do we consider wetlands as we plan this project?.................................................................................................19 What are the key points of this report?..........................................................................................................................20 Existing Conditions ............................................................................................................................................................22 What is the study area for wetlands and how did we define it?.....................................................................................22 What regulations govern project activities in wetlands? ................................................................................................22 What existing information is there for wetlands in the study area?................................................................................23 How did we identify wetland boundaries in the field? ....................................................................................................25 What qualifies an area as a “wetland” under the delineation manuals?.........................................................................26 How did we characterize wetlands in the study area?...................................................................................................28 Where are the wetlands in the study area and what are their characteristics?..............................................................29 Green River Basin.....................................................................................................................................................38 Springbrook Creek Basin..........................................................................................................................................40 How did we evaluate wetlands and what rating systems did we use?...........................................................................42 How are the wetlands in the study area ranked?...........................................................................................................43 How did we assess the wetland functions and values?.................................................................................................45 What functions do study area wetlands provide? ..........................................................................................................46 Potential Effects.................................................................................................................................................................49 How did we calculate wetland areas and effects?.........................................................................................................49 Will project construction affect wetlands?......................................................................................................................49 Permanent effects.....................................................................................................................................................49 Temporary effects.....................................................................................................................................................52 Will project operation affect wetlands?..........................................................................................................................52 Would the No Build Alternative affect wetlands?...........................................................................................................53 Will this project result in any indirect effects?................................................................................................................53 Measures to Avoid or Minimize Project Effects..................................................................................................................55 What has been done to avoid or minimize negative effects on wetlands?.....................................................................55 Will the project compensate for unavoidable negative effects on wetlands?.................................................................55 References.........................................................................................................................................................................57 TABLE OF CONTENTS Renton Nickel Improvement Project ii Wetland Discipline Report Appendix A - Wetland Delineation Data Sheets Wetland Rating Forms Wetland Functional Assessment Forms E XHIBITS Exhibit 1. Project Vicinity Map............................................................................................................................................. 1 Exhibit 2. Project Overview Section 1................................................................................................................................. 3 Exhibit 3. Project Overview Section 2................................................................................................................................. 4 Exhibit 4. Project Overview Section 3................................................................................................................................. 5 Exhibit 5. Project Overview Section 4................................................................................................................................. 6 Exhibit 6. Project Overview Section 5................................................................................................................................. 7 Exhibit 7. Project Overview Section 6................................................................................................................................. 8 Exhibit 8. Project Overview Section 7................................................................................................................................. 9 Exhibit 9. Project Overview Section 8............................................................................................................................... 10 Exhibit 10. Presence of Water Relative to the Root Zone in Wetland and Upland Areas................................................. 27 Exhibit 11. Types of Wetlands and Their Typical Positions in the Landscape.................................................................. 28 Exhibit 12-A. Renton Nickel Improvement Project Wetlands............................................................................................ 30 Exhibit 12-B. Renton Nickel Improvement Project Wetlands............................................................................................ 31 Exhibit 12-C. Renton Nickel Improvement Project Wetlands............................................................................................ 32 Exhibit 12-D. Renton Nickel Improvement Project Wetlands............................................................................................ 33 Exhibit 12-E. Renton Nickel Improvement Project Wetlands............................................................................................ 34 Exhibit 12-F. Renton Nickel Improvement Project Wetlands............................................................................................ 35 Exhibit 12-G. Renton Nickel Improvement Project Wetlands............................................................................................ 36 Exhibit 12-H. Renton Nickel Improvement Project Wetlands............................................................................................ 37 Exhibit 13. Summary of Wetlands Located within the Green River Basin......................................................................... 39 Exhibit 14. Summary of Wetlands Located within the Springbrook Creek Basin.............................................................. 41 Exhibit 15. Point Totals for Higher and Lower Value Wetlands Based on Ecology Rating System .................................. 42 Exhibit 16. Wetland Ratings in Study Area....................................................................................................................... 44 Exhibit 17. Wetland Functions and Values in the Study Area........................................................................................... 47 Exhibit 18. Filled or Disturbed Wetlands in the Study Area............................................................................................... 50 Exhibit 18. Filled or Disturbed Wetlands in the Study Area (continued)............................................................................ 51 Renton Nickel Improvement Project Wetland Discipline Report iii GLOSSARY best management practices (BMPs) Physical, structural, and/or managerial practices that, when used singly or in combination, prevent or reduce pollutant discharges (e.g., installing sedimentation fencing and straw bales during clearing and grading activities). buffer A designated area along and adjacent to a stream or wetland that may be regulated to control the negative effects of adjacent development on the aquatic resource. construction footprint The physical area impacted by project construction activities. emergent A plant that grows rooted in shallow water or saturated soil, where most of the plant emerges from the water or above the ground surface and stands vertically. fill material Any material placed in an area to increase surface elevation. forbs Broad-leaved flowering plants. GMA The 1990 Growth Management Act (GMA) created, for the first time, a detailed growth management scheme for the state of Washington. It requires most counties and cities to produce a comprehensive plan. Each plan must address land use, transportation, public facilities, utilities, housing, and other issues. hydric soil Soils that develop anaerobic (absence of oxygen) conditions under persistently wet conditions. hydrology The science dealing with the properties, distribution, and circulation of water. hydrologically connected Linked to or associated with the water source of another system either through surface water, a stream, groundwater etc. hydrophytic vegetation Vegetation that is able to grow and thrive under wet soil conditions. mitigation Defined in the Washington Administrative Code (WAC) 197-11-766 as: (1) avoiding the impact altogether by not taking a certain action or parts of an action; (2) minimizing impacts by limiting the degree or magnitude of the action and its implementation, by using appropriate technology, or by taking affirmative steps to avoid or reduce impacts; (3) rectifying the impact by repairing, rehabilitating, or restoring the affected environment; (4) reducing or eliminating the impact over time by preservation and maintenance operations during the life of the action; (5) compensating for the impact by replacing, enhancing or providing substitute resources or environments; and/or (6) monitoring the impact and taking appropriate corrective measures. palustrine In the USFWS classification system, freshwater areas (having less than 0.5 parts per thousand ocean-derived salts) dominated by trees, shrubs, persistent emergents, mosses, or lichens. These areas can be tidal (waters which alternate by rising and falling) or non-tidal. Palustrine also includes wetlands lacking this vegetation but having the following characteristics: (1) area less than 20 acres; (2) no active wave-formed or bedrock shoreline; (3) deepest water depth is less than 6.6 feet at low water. palustrine aquatic bed (PAB) In the USFWS classification system, aquatic beds are dominated by plants that grow and form a continuous cover principally on or at the surface of the water, including algal mats, detached floating mats, and rooted vascular plant assemblages. Total vegetation cover is greater than 80 percent. palustrine emergent (PEM) In the USFWS classification system, a wetland characterized by erect, rooted, non-woody plants such as cattails, rushes, and sedges. palustrine forested (PFO) In the USFWS classification system, a wetland characterized by woody vegetation that is 20 feet tall or taller. GLOSSARY Renton Nickel Improvement Project iv Wetland Discipline Report palustrine scrub-shrub (PSS) In the USFWS classification system, areas dominated by woody vegetation less than 20 feet tall, such as trees, shrubs or young trees that are stunted due to environmental conditions. riparian corridor The land and the vegetation community directly adjacent to (or surrounding) a natural or artificial waterway including streams, rivers, wetlands and lakes. SMA The Shoreline Management Act (SMA) of 1971 is a state law that requires local jurisdictions to create a Shoreline Master Program (SMP). The purpose of the SMP is to regulate development within sensitive shoreline areas. Shorelines, according to the SMA, include all areas typically within 200 feet inland from principal bodies of water (rivers, streams, lakes, tidal areas) and associated wetlands. The local SMP, or Master Program, must provide at least minimal standards of protection for shoreline areas. The final program is subject to approval by the state. study area The area specifically evaluated for the presence of wetlands. This area is similar to the project limits but it includes areas within the I-405 right-of-way and areas that would be affected by other necessary project elements such as stormwater treatment facilities, noise walls, and surface street improvements. wetland Wetlands are formally defined by the U.S. Army Corps of Engineers , the U.S. Environmental Protection Agency , the Washington Shoreline Management Act of 1971 (SMA) , and the Growth Management Act (GMA) as: “… those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.” The SMA and the GMA definitions add: “Wetlands do not include those artificial wetlands intentionally created from non-wetland sites, including, but not limited to, irrigation and drainage ditches, grass-lined swales, canals, detention facilities, wastewater treatment facilities, farm ponds, and landscape amenities, or those wetlands created after July 1, 1990 that were unintentionally created as a result of the construction of a road, street, or highway. Wetlands may include those artificially-created wetlands intentionally created from non-wetland areas to mitigate the conversion of wetlands.” wetland boundary The point on the ground at which a shift from wetlands to nonwetlands or aquatic habitat occurs. These boundaries usually follow topographic contours. wetland hydrology The presence of water during a portion (between 5 and 12.5 percent) of the annual growing season. Renton Nickel Improvement Project Wetland Discipline Report v ACRONYMS AND ABBREVIATIONS USED IN THIS REPORT BNSF Burlington Northern Santa Fe BMPs best management practices CAD computer-aided drafting Corps U.S. Army Corps of Engineers CSS Context Sensitive Solutions CWA Clean Water Act Ecology Washington State Department of Ecology FHWA Federal Highway Administration GIS Geographic information system GMA Growth Management Act HOV High-occupancy vehicle NRCS Natural Resources Conservation Service NWI National Wetlands Inventory PAB palustrine aquatic bed PEM palustrine emergent PFO palustrine forested PSS palustrine scrub-shrub SMA Shoreline Management Act USFWS United States Fish and Wildlife Service WSDOT Washington State Department of Transportation Renton Nickel Improvement Project vi Wetland Discipline Report This page intentionally blank. Renton Nickel Improvement Project Wetland Discipline Report 1 INTRODUCTION What is the Renton Nickel Improvement Project? The Renton Nickel Improvement Project is a highway expansion project that will improve mobility and safety through Tukwila and Renton. On I-405, this project begins just east of the I-5/I-405 interchange in Tukwila and extends north past the Cedar River to the SR 169 (Maple Valley Highway) interchange. The project will build an additional lane both northbound and southbound between I-5 and SR 169. On SR 167, the project will extend the southbound high-occupancy vehicle (HOV) lane north to I-405 and add a southbound auxiliary lane from I-405 to the SW 41st Street off-ramp. These limits comprise the study area for the project. Prior to planning this specific project, WSDOT created the I-405 Corridor Program. This program provides a comprehensive strategy to reduce congestion and improve mobility throughout the I-405 corridor. The corridor begins at the I-5 interchange in the city of Tukwila and extends northward 30 miles to the I-5 interchange in the city of Lynnwood. The program’s purpose is to provide an efficient, integrated, and multimodal system of transportation solutions. Using the I-405 Corridor Program’s Selected Alternative as the Master Plan to improve I-405, WSDOT developed relatively low cost, congestion relief roadway improvements as an interim step in achieving the Master Plan. As part of this effort, WSDOT began to define the Renton Nickel Improvement Project. The Renton Nickel Improvement Project was developed as part of a first step in providing a focused strategy to improve I-405 between I-5 in Tukwila and SR 169 in Renton and SR 167 southbound from I-405 to SW 41st Street, see Exhibit 1. This discipline report analyzes two project alternatives: the No Build Alternative and the Build Alternative. Exhibit 1. Project Vicinity Map G r e en R i v e r C e d ar Riv er Interurban TrailCedar River Interpretive Trail Panther Creek Wetlands Green River TrailBlack River Riparian Forest Fort Dent Park Cedar River Park Liberty Park SW 41st St S W 3 4 t h S t S W 2 7 t h S t SW 16th St Southcenter ParkwayW Valley HwyI n t e r u r ban Ave SMa ple V alley H w yRainier Ave SS W Sun s e t B lvdS W 7 t h S t S W G r a d y W a y Lind Ave SWTUKWILA RENTON S pri n g br ook CreekBenson Rd SSW 23rd St Talbot Rd SBenson Dr SI-405 Northern Project Limit at SR 169 I-405 Southern Project Limit at I-5 !"`$ %&e( Aæ Aç Aí SR 167 Southern Project Limit at SW 41st St 0 0.25 0.5 Miles M AÅ Arterial Road Freeway Trail Stream Lake Park Municipality INTRODUCTION Renton Nickel Improvement Project 2 Wetland Discipline Report What is the No Build Alternative? The No Build Alternative assumes that only routine activities such as road maintenance, repair, and safety improvements would take place over the next 20 years. This alternative does not include improvements to increase roadway capacity or reduce congestion. For these reasons, it does not satisfy the project’s purpose—improve I-405 between I-5 in Tukwila and SR 169 in Renton and SR 167 southbound from I-405 to SW 41st Street. The No Build Alternative has been evaluated in this discipline report to establish a baseline for comparing the effects associated with the Build Alternative. What is the Build Alternative? The new lanes that will be built under this project are: An I-405 northbound general-purpose (GP) lane from I-5 to the SR 167 off-ramp. An I-405 northbound auxiliary lane from the SR 167 to I-405 on-ramp to the SR 169 off-ramp. An I-405 southbound auxiliary lane from the SR 169 to I-405 on-ramp to the SR 167 off-ramp. An I-405 southbound GP lane from the SR 167 to I-405 on-ramp to the I-5 off-ramp. A SR 167 southbound auxiliary lane from I-405 to the SW 41st Street off-ramp. Also, the existing inside HOV lane will be extended north to I-405 from its present starting point in the vicinity of SW 21st Street. See Exhibits 2 through 9 show the project features. In addition to adding lanes to I-405 and SR 167, this project will provide the following improvements. Improve Interchanges Minor modifications will be made to the ramps at the SR 167 interchange: The one-lane ramp from northbound I-405 to SR 167 will be widened to a 2-lane off connection, which provides a dedicated lane to southbound SR 167 and a dedicated lane to northbound Rainer Avenue. See Exhibit 5. Traffic from two consecutive single-lane on- ramps from southbound I-405 to SR 167 will be separated by a concrete barrier. This will provide a smoother transition to the mainline and reduce congestion on the on-ramps. What is an auxiliary lane? An auxiliary lane is a lane added between interchanges—from one on-ramp to the next off-ramp. It is dedicated to traffic entering and leaving the freeway and provides motorists with more time and extra room to accelerate or decelerate and merge when getting on and off the freeway. 89:P 89:T Existing On-ramp On-ramp with proposed auxiliary lane INTRODUCTION Renton Nickel Improvement Project Wetland Discipline Report 3 T u k w i l a P a r k w a y I-405 Southern Project Limit at I-5 Gilliam Creek Cottage Creek Westfield Shoppingtown MallSouthcenter ParkwaySouthcenter Blvd 65th Ave STUKWILA RENTON!"`$ %&e( Sec. 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí I-405 Northboundbound Improvements: A general-purpose lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. I-405 Southbound Improvements: A general-purpose lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. M0250500 Feet I-405 NORTHBOUND Existing Proposed I-405 SOUTHBOUND Existing Proposed Renton Renton Piped River/Creek Channel Open River/Creek Channel Ecology EmbankmentÃÃÃÃÃÃÃÃÃÃÃÃ Retaining Wall Stormwater Flow Control Facility New Pavement Easement Acquisition Parcel Acquisition Existing ROW Areas of Construction New ROW Exhibit 2. Project Overview Section 1 INTRODUCTION Renton Nickel Improvement Project 4 Wetland Discipline Report ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃInterurban TrailFort Dent Park W Valley HwyInterurban Ave S RENT ONT UKWI L AG r e en RiverSouthcenter B lv d65th Ave SAí %&e( %&e(UP RRBNSF RRBridge Restripe Only Bridge Rail Replacement Bridge Rail Replacement M o n s t e r R d S WTUKWILA RENTON!"`$ %&e( Sec. 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí I-405 Northbound Improvements: A general-purpose lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. I-405 Southbound Improvements: A general-purpose lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. M0250500 Feet I-405 SOUTHBOUND Existing Proposed Renton Renton I-405 NORTHBOUND Existing Proposed %&e( Retaining Wall Piped River/Creek Channel Open River/Creek Channel ÃÃÃÃÃÃÃÃÃÃÃÃ Ecology Embankment Stormwater Flow Control Facility New Pavement Areas of Construction Easement Acquisition Parcel Acquisition Existing ROW New ROW Exhibit 3. Project Overview Section 2 INTRODUCTION Renton Nickel Improvement Project Wetland Discipline Report 5 ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃ SW 16th St S W G r a d y W a y SW G ra d y W a y Oakesdale Ave SWSW 16th St %&e( Potential Staging Area Bridge Replacement S prin g br o o k Cr eekBridge Replacement TUKWILA RENTON!"`$ %&e( Sec. 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí I-405 Northbound Improvements: A general-purpose lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. The existing Springbrook Creek and Oakesdale Avenue bridges will be replaced and the existing culvert will be removed. I-405 Southbound Improvements: A general-purpose lane will be added by restriping the existing pavement and adding pavement up to 70 feet to the outside at some locations. The existing Springbrook Creek and Oakesdale Avenue bridges will be replaced and the existing culvert will be removed.M0250500 Feet I-405 SOUTHBOUND Existing Proposed Renton Renton I-405 NORTHBOUND Existing Proposed Piped River/Creek Channel Open River/Creek Channel ÃÃÃÃÃÃÃÃÃÃÃÃ Ecology Embankment Retaining Wall Stormwater Flow Control Facility New Pavement Areas of Construction Easement Acquisition Parcel Acquisition Existing ROW New ROW Exhibit 4. Project Overview Section 3 INTRODUCTION Renton Nickel Improvement Project 6 Wetland Discipline Report ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃ SW 19th StLind Ave SWS G r a d y W a y Aæ %&e( Potential Staging Area Noise Wall Renton CinemaRolling Hills Creek Panther Creek Wetlands SW 16th St Lake AveSouthRainier Ave STUKWILA RENTON!"`$ %&e( Sec. 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí I-405 Northbound Improvements: A general-purpose lane will be added up to the SR 167 interchange and an auxiliary lane will be added from the SR 167 to I-405 on-ramp north. These lanes will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. I-405 Southbound Improvements: An auxiliary lane will be added up to the I-405 to SR 167 on-ramp and a general-purpose lane will be added south of the interchange. These lanes will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. SR 167 Southbound Improvements: An auxiliary lane will be added by restriping existing pavement and adding up to 19 feet of pavement at the outside at some locations. The existing HOV lane will be extended north from SW 21st Street to the interchange with I-405.M0250500 Feet I-405 SOUTHBOUND Existing Proposed Renton Renton I-405 NORTHBOUND Existing Proposed SR 167 SOUTHBOUND Existing Proposed Renton ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃ ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃ Piped River/Creek Channel Open River/Creek Channel Proposed Noise Wall ÃÃÃÃÃÃÃÃÃÃÃÃ Ecology Embankment Retaining Wall Stormwater Flow Control Facility New Pavement Areas of Construction Easement Acquisition Parcel Acquisition Existing ROW New ROW Exhibit 5. Project Overview Section 4 INTRODUCTION Renton Nickel Improvement Project Wetland Discipline Report 7 ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃPanther Creek Wetlands S W 2 7 t h S t Talbot Rd SEast Valley RdTalbot Rd SPotential Staging Area SW 23rd St TUKWILA RENTON!"`$ %&e( Sec. 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí SR 167 Improvements: In addition to extending the HOV lane north from SW 21st Street, an auxiliary lane will be added by restriping the existing pavement and adding pavement up to 19 feet to the outside at some locations. M0250500 Feet SR 167 SOUTHBOUND Existing Proposed Renton RentonÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃ Piped River/Creek Channel Open River/Creek Channel ÃÃÃÃÃÃÃÃÃÃÃÃ Ecology Embankment Retaining Wall Stormwater Flow Control Facility New Pavement Areas of Construction Easement Acquisition Parcel Acquisition Existing ROW New ROW Exhibit 6. Project Overview Section 5 INTRODUCTION Renton Nickel Improvement Project 8 Wetland Discipline Report ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃSW 41st St S W 3 3 r d S t Panther CreekEast Valley RdTalbot Rd SLind Ave SWAæ SR 167 Southern Project Limit at SW 41st St TUKWILA RENTON!"`$ %&e( Sec. 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí SR 167 Improvements: An auxiliary lane will be added by restriping the existing pavement and adding pavement up to 19 feet to the outside at some locations. The new lane will tie into the existing ramp connection to SW 41st Street. M0250500 Feet SR 167 SOUTHBOUND Existing Proposed Renton Renton Piped River/Creek Channel Open River/Creek Channel ÃÃÃÃÃÃÃÃÃÃÃÃ Ecology Embankment Retaining Wall Stormwater Flow Control Facility New Pavement Areas of Construction Easement Acquisition Parcel Acquisition Existing ROW New ROW Exhibit 7. Project Overview Section 6 INTRODUCTION Renton Nickel Improvement Project Wetland Discipline Report 9 ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃS G rady W ayB e a c o n S 7 t h S tWilliams %&e( Potential Staging Area Replace Bridge Bridge Widening Existing Bridge to be Demolished Thunder Hills Creek Rolling Hills Creek Noise Wall Benson Rd STalbot Rd STUKWILA RENTON!"`$ %&e( Sec, 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí I-405 Northbound Improvements: An auxiliary lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. I-405 Southbound Improvements: An auxiliary lane will be added by restriping the existing pavement and adding pavement up to 24 feet to the outside at some locations. Benson Rd S Improvements: The Benson Rd S overpass will be replaced and realigned to the west of its current location. The new overpass will have 2 lanes with 5-foot bike lanes on both sides and a 6-foot sidewalk on the west side.M0250500 Feet I-405 NORTHBOUND Existing Proposed I-405 SOUTHBOUND Existing Proposed Renton Renton Parcel Acquisition New ROW Existing ROW Easement Acquisition Areas of Construction New Pavement Stormwater Flow Control Facility Retaining Wall ÃÃÃÃÃÃÃÃÃÃÃÃ Ecology Embankment Proposed Noise Wall Piped River/Creek Channel Open River/Creek Channel Exhibit 8. Project Overview Section 7 INTRODUCTION Renton Nickel Improvement Project 10 Wetland Discipline Report C edar River Cedar River Interpretive Trail Cedar River Park Liberty Park Ma p l e V a ll e y H w y H o u s e r W a y S N 3 r d S t Bronson Wa y N%&e( I-405 Northern Project Limit at SR 169 Aç Restripe Only Main AvenueCedar Ave SRenton Ave STUKWILA RENTON!"`$ %&e( Sec. 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí I-405 Northbound Improvements: An auxiliary lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. I-405 Southbound Improvements: An auxiliary lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. M0250500 Feet I-405 NORTHBOUND Existing Proposed I-405 SOUTHBOUND Existing Proposed Renton Renton Piped River/Creek Channel Open River/Creek Channel ÃÃÃÃÃÃÃÃÃÃÃÃ Ecology Embankment Retaining Wall Stormwater Flow Control Facility New Pavement Areas of Construction Easement Acquisition Parcel Acquisition Existing ROW New ROW Exhibit 9. Project Overview Section 8 INTRODUCTION Renton Nickel Improvement Project Wetland Discipline Report 11 Improve Benson Road The Benson Road overpass will be replaced and realigned to accommodate the southbound auxiliary lane on I-405 as well as future improvements to I-405 as shown on Exhibit 8. Improvements on Benson Road include a 6-foot sidewalk on the west side and 5-foot bike lanes on both sides. Widen and replace bridges Several bridges within the study area will be widened or replaced based on present location, cost, and existing soil conditions. To construct the new lanes, the project will: Widen Talbot Road Bridge on both the northbound and the southbound sides. See Exhibit 8. Replace Springbrook Creek Side Channel Bridge and Oakesdale Avenue Bridge with new southbound and northbound structures and remove the Springbrook Creek box culvert. See Exhibit 4. Replace the rail on the I-405 bridges over SR 181 and the Union Pacific and Burlington Northern Santa Fe railroads. The project will not affect the I-405 bridges over the Green River, Lind Avenue, or the Cedar River. The project will also not affect the Cedar Avenue or Renton Avenue overpasses. The roadway will be restriped in these areas to accommodate the new lanes. Use retaining walls Widening I-405 and SR 167 will require retaining walls to minimize the construction footprint and right-of-way acquisition. Retaining walls will also help avoid and minimize effects to wetlands and other sensitive areas. Improve culverts WSDOT anticipates that construction will affect some existing stormwater cross culverts and one stream culvert. Associated culvert improvements include extending the existing structures due to widening the roadway and stabilizing culvert ends with rock or retaining walls. The I-405 Team will conduct a hydraulic analysis of the culverts to ensure that the modifications will have no effect on the base flood elevations. See the Fisheries and Aquatic Resources Discipline Report for detailed discussion on fish passage. Why rebuild Benson Road on a new alignment over I-405? By building the new overpass to the west on a new alignment, the new structure can be constructed while the existing structure remains open to traffic. Traffic can then be shifted onto the new structure, while the old overpass is demolished. What does a “rail” replacement involve? Typically, a bridge rail replacement project consists of making minor adjustments to the width of the bridge deck and replacing the guard rail or barrier. This type of project does not include adding new bridge columns or footings. INTRODUCTION Renton Nickel Improvement Project 12 Wetland Discipline Report Build a noise wall One noise wall will be built on the northbound side of the freeway as shown on Exhibits 5 and 8. The wall will begin at the intersection of South 14th Street and South 15th Street and follow South 14th Street east to Talbot Road. This wall will be approximately 2,150 feet long and 18 feet tall. How will stormwater from the project be managed? Stormwater from the project will be managed for both quality and peak flows using currently accepted best management practices (BMPs). The I-405 Team has designed the stormwater management facilities to comply with the following guidelines and procedures: WSDOT Highway Runoff Manual M 31-16 WSDOT Hydraulics Manual M 23-03 Stormwater treatment facilities The project will add new impervious surface within the study area, most of which will be within the Springbrook Creek basin. This project will treat runoff for an area equal to 100 percent of these new surfaces. The project will use BMPs that the HRM lists as enhanced treatment facilities. The I-405 Team has proposed that stormwater be treated using a combination of these facilities. In most of the study area, ecology embankments will be used to capture runoff from the edge of the pavement and provide water quality treatment. Ecology embankments also serve to convey treated runoff to receiving waters or to flow control facilities as required. The project also includes a combined stormwater quality wetland and detention facility that addresses water quality and flow control in one facility. Exhibits 2 through 9 show the location of stormwater facilities that will be built for this project. Ecology Embankment Cross-Section What are the guidelines for stormwater management facilities? Water quality treatment will be provided for an area equal to the new impervious surfaces created on the project. Impervious surfaces, such as pavement, are those that do not allow water to penetrate into the ground. Stormwater from new impervious surfaces or an equal area will be controlled in detention facilities. This process allows water to be held (detained) and thus released at rates that are equal to existing conditions. INTRODUCTION Renton Nickel Improvement Project Wetland Discipline Report 13 Drainage Collection and Conveyance Some changes to existing drainage will be necessary to provide flow control and water quality treatment to address the new impervious area added by the project. However, existing storm drainage systems will be kept to the greatest extent possible and existing flow patterns will be maintained. Where roadway widening affects drainage ditches that convey water from adjacent private properties, the project design will assure that existing conveyance capacities are maintained. What environmental and utilities issues influenced the project design and what was done to avoid and minimize project effects? Throughout the development of the Renton Nickel Improvement Project design, environmental elements were reviewed and design features were modified to avoid or minimize negative effects to the environment. Influence on the project design came from: Soil Conditions: the soils in the project area are highly prone to accentuate earthquake shaking, which influences how bridges can be widened or replaced. Noise: highway noise in the project area already exceeds acceptable levels, which means that including noise walls as part of the project had to be considered. Wetland Locations: many wetlands are located along the edges of the highway, which influence whether the widened sections will use retaining walls or fill slopes. Historical Sites: some historic sites exist within the study area, so the project design was coordinated to avoid these properties. Because the I-405 Team planned for these environmental considerations, several design features have the benefit of avoiding or minimizing potential effects due to the project. These design features are described from south to north below. I-405, I-5 to SR 167 WSDOT will construct a retaining wall from west of the 68th Avenue structure over I-405 at Tukwila Parkway What are detention facilities? These facilities control stormwater runoff so that it can be released at a controlled rate. Two types are commonly used: Ponds. Vaults. Similar to a pond, but with a hard-sided construction. These concrete structures function like a pond but also provide detention storage. INTRODUCTION Renton Nickel Improvement Project 14 Wetland Discipline Report The proposed design modifications allow the additional lanes to be added over the Green River by restriping instead of bridge widening. This avoids effects on the river, stream habitat, floodplain, and Interurban Trail. to the Green River. This wall avoids the need to construct a fill slope that would extend into Gilliam Creek. See Exhibit 2. WSDOT will provide a narrower outside shoulder on northbound I-405 at the Green River Bridge. The shoulder will vary from 10 to just over 3 feet at the west abutment of the existing bridge. Narrowing the shoulder avoids modifications to the existing bridge. As a result, the design also avoids effects to the river, the 100-year floodplain, the ordinary high water level, and adjacent riparian zones. At the SR 181 interchange, the bridge and ramp will be restriped to provide the new general-purpose lane and ramp improvements. This approach minimizes the need to widen the existing SR 181 Bridge, reconstruct the SR 181 interchange, or modify the Southcenter Boulevard crossing of the Green River. This in turn avoids relocating or diverting the Interurban Trail, which goes under the bridge. See Exhibit 3. Near the Westfield Shoppingtown Mall, a large Seattle Public Utilities water transmission line parallels I-405. WSDOT will line this pipe so that is can support the loads from the new roadway embankment. This approach allows the line to stay in its present location. WSDOT will remove the existing I-405 bridges over the Springbrook Creek side channel and Oakesdale Avenue and replace them with a single northbound and a single southbound bridge. This approach will allow for the removal of the Springbrook Creek box culvert. Construction of the new bridges will be phased with the southbound bridge built slightly to the north of the existing roadway. This phasing minimizes the need to construct temporary roadway to maintain traffic operations. WSDOT also evaluated the location of the new bridge piers and selected locations that will minimize the effect on the existing stream, stream buffer, and trail that crosses under the bridge. WSDOT will construct a narrower exit gore from I-405 to the northbound ramp at the SR 167 interchange as shown in Exhibit 5. By building a narrower exit gore, the project can be constructed within the existing right- of-way. This has the benefit of avoiding right-of-way acquisition, avoiding effects to the wetland outside the right-of-way, and avoiding effects to the existing Lind Avenue Bridge. What is an exit gore? An exit gore is a roadway feature that separates an exiting lane from the main lanes. An exit gore can be defined either by paint stripes, raised buttons, physical barriers, or a combination of these. INTRODUCTION Renton Nickel Improvement Project Wetland Discipline Report 15 Retaining walls will help to avoid and minimize effects on the Panther Creek wetlands along SR 167 SR 167, southbound from I-405 to SW 41st Street WSDOT will build a retaining wall along a large portion of the west edge of SR 167 southbound instead of an earth fill slope. See Exhibits 6 and 7. The retaining wall minimizes effects on three wetlands. The retaining wall has the added benefit of minimizing right-of-way needs and reduces the effect on existing utility crossings, in particular, the City of Seattle’s 60- inch water line and Olympic Petroleum’s two high pressure pipelines, which all cross under SR 167. I-405, SR 167 to SR 169 WSDOT will add a lane by restriping I-405 northbound next to the Talbot Hill retaining wall immediately east of the SR 167 interchange. Restriping instead of widening avoids the need to reconstruct the existing Talbot Hill retaining wall and avoids effects on properties south of I-405 in this area. Between Talbot Road and the “S-Curves”, northbound I-405 will be widened to achieve standard lane and shoulder widths. Most of this length will be supported by retaining walls to minimize effects to Thunder Hills Creek, adjacent properties, and the existing cut slope south of I-405. To support the fill required to widen the roadway on the north side of I-405 next to the outfall for the original Rolling Hills Creek culvert, the design uses a retaining wall. By using the retaining wall, the project improvements at this location can be constructed without affecting the existing culvert. WSDOT will use a non-standard design for the I-405 to SR 167 exit ramp. The changes from the design standards include not providing a recovery lane, narrowing the distance between the through lane and ramp, and providing narrower shoulders. While these changes deviate from WSDOT design standards they are an improvement over existing conditions. These features will avoid effects to the existing Rolling Hills Creek/Thunder Hills Creek channel located between I-405 and the Renton Cinema complex as shown in Exhibit 5. Using retaining walls along the west side of Benson Road avoids effects to Rolling Hills Creek and the wetlands east of Talbot Road. WSDOT will use retaining walls to support widening southbound I-405 south of the Cedar Avenue overpass. Using retaining walls versus a fill slope, avoids encroaching on Cedar Avenue and Main Avenue in Renton. What is a recovery lane? A recovery lane is a paved area adjacent to an off-ramp. This area gives drivers, who find themselves exiting the freeway unintentionally, room to maneuver back onto the freeway. INTRODUCTION Renton Nickel Improvement Project 16 Wetland Discipline Report WSDOT also plans to replace the existing Benson Road overpass on a new alignment. The new bridge will be located slightly to the west of the existing bridge. This will allow traffic to continue to use the existing overpass until the new one is completed. This will minimize disruption for local traffic and to emergency response vehicles. Where northbound and southbound I-405 passes under the Renton Avenue and Cedar Avenue overpasses, WSDOT will add lanes by restriping. This design avoids replacing the two overpasses; however, the available area does not allow the standard shoulder and lane widths. WSDOT shifted a proposed stormwater facility to avoid effects to the existing Renton Coal Mine Hoist Foundation site south of Benson Road. This site is on the Washington Historic Register. What is planned for wetland and stream mitigation? WSDOT will compensate for unavoidable effects to wetlands with credits from the Springbrook Creek Wetland and Habitat Mitigation Bank. Mitigation is needed for 1.66 acres of wetlands. The Springbrook Creek Wetland and Habitat Mitigation Bank is being developed as a joint effort between WSDOT and the City of Renton. This ‘bank’ will construct a new high quality wetland complex that will serve to replace other wetlands that are filled in by projects such as the Renton Nickel Improvement Project. The location of the bank is shown to the left. In addition to wetland mitigation, the site will also provide flood storage mitigation. The Springbrook Creek Wetland and Habitat Mitigation Bank will be one of the first urban mitigation banks to be certified in Washington. To mitigate project effects on streams, WSDOT will remove the existing Springbrook Creek box culvert. With the new I-405 southbound and northbound bridges that will span both Springbrook Creek and Oakesdale Avenue, the box culvert is no longer needed. After the new bridges are in place, the box culvert will be removed and the streambed in that area will be restored. This will improve fish habitat within Springbrook Creek. Any additional stream mitigation required to offset project effects will be accommodated within the project vicinity. Renton Coal Mine Hoist Foundation site looking west r Interurban TrailPanther Creek Wetlands Green River TrailFort Dent Park SW 41st St S W 3 4 t h S t S W 2 7 t h S t SW 16th St W Valley HwyS W 7 t h S t S W G r a d y W a y Lind Ave SWS pri n g br ook CreekSW 23rd St Aæ Aí M 0 0.25 0.5 Miles 100 Year Floodplain 500 Year Floodplain Park Renton Tukwila Springbrook Creek Wetland & Habitat Mitigation Bank Wetlands Local Road Legend Trail Arterial Road Freeway River/Creek Channel Study Area Limits Springbrook Creek Wetland and Habitat Mitigation Bank INTRODUCTION Renton Nickel Improvement Project Wetland Discipline Report 17 What benefits will the project provide? The Build Alternative will benefit the area by reducing congestion at chokepoints, reducing the duration of congestion during peak commuter travel hours, and improving freight movement. This section of I-405, from the I-5 interchange to SR 169, is congested due to large traffic volumes and merging and diverging traffic. The new lanes will help relieve congestion by adding roadway capacity. This in turn will improve safety by providing drivers with more time and extra room to accelerate or decelerate and move into and out of the stream of traffic when getting on and off the freeway. This provides a smoother transition for motorists as they get on and off I-405 in Tukwila and Renton and helps decrease rear- end and sideswipe collisions. The project reduces congestion approaching the SR 167 interchange, and it complements the completed southbound I-405 to southbound SR 167 flyover ramp. This project will construct one noise wall along northbound I-405 from the intersection of South 14th Street and South 15th Street east to Talbot Road. This wall will benefit residents in that area by lowering the overall noise levels. Another benefit of this project is that it continues the application of the Context Sensitive Solutions (CSS) design choices made by the communities within the I-405 corridor. The Benson Road realignment will reflect the most comprehensive application of these design choices as explained further in the next section. How will the project incorporate community design preferences? The Renton Nickel Improvement Project is being planned, developed, and designed according to CSS guidelines. These guidelines establish the community design preferences used to design the project features. Working within the framework for the overall I-405 corridor, the Urban Design Guidelines will be adapted to incorporate the communities’ design preferences. These preferences will be included in the contract documents prepared for the Renton Nickel Improvement Project. The selected I-405 theme of “Culture, Nature, and Progress,” with nature This rendering shows the new Benson Road overpass with the CSS Guidelines applied INTRODUCTION Renton Nickel Improvement Project 18 Wetland Discipline Report being the dominant theme, will be carried into corridor- wide and local I-405 designs. The new Benson Road overpass is the main project feature that will receive CSS treatment. The new southbound and northbound bridges over Springbrook Creek and Oakesdale Avenue will also receive CSS treatments. The rest of the project elements will be designed to match in color and vegetation type only, as many of these elements will be affected by construction of future Master Plan projects. During future Master Plan phases for the overall I-405 corridor, the approved CSS guidelines will be applied throughout. How will the project be constructed? Construction of the entire Renton Nickel Improvement Project is expected to take two years, beginning in early 2008 and being completed in late 2010. However, construction activity will not be constant for the entire study area throughout this time, and in some locations, the work will take substantially less time than two years. Construction will pose some minor inconveniences because of localized travel delays due to temporary lane closures and narrowed lanes and shoulders. At-grade construction At-grade construction, which occurs on the same elevation as the existing lanes, will be staged to minimize traffic delays and detours. Typically, lanes are shifted toward the median. WSDOT then places a concrete barrier to close off the shoulder. Staging allows construction to occur safely without closing lanes for the duration of construction. Access to construction areas will occur from the roadway side to minimize property effects. Bridge construction Construction of the I-405 bridges will occur in multiple stages to minimize traffic delays and detours. The following describes typical staging for bridge construction. As the first stage, traffic is shifted toward the I-405 median and the existing lanes and shoulders are narrowed slightly to allow widening of the existing structure or construction of the new bridge depending on the design. In the next stage, traffic is shifted onto the new bridge area. If the bridge is being replaced rather than simply widened, the old structure is demolished after traffic is shifted to the new bridge. At-grade construction for this project will likely be staged similar what is shown above. Here, the southbound lanes of I-5 were shifted toward the median and a concrete barrier closed off the shoulder to provide crews a safe work area. INTRODUCTION Renton Nickel Improvement Project Wetland Discipline Report 19 The new Benson Road overpass will also be staged. The new structure will be built to the west, while the existing overpass remains in service. After traffic has been shifted onto the new overpass, the existing structure will be demolished. Staging areas Construction staging areas along I-405 and SR 167 will be within the WSDOT right-of-way. Potential staging areas have been identified as shown on Exhibits 2 through 9. Traffic control Detour agreements with the local agencies will be obtained after WSDOT awards the contract. A traffic control plan will be approved by WSDOT prior to starting construction. The plan’s primary objectives will be to provide a safe facility, to streamline the construction schedule, and to minimize reductions to existing traffic capacity. To lessen effects on traffic, the duration of activities will be minimized and reductions in capacity will be limited and will be targeted to a period when they will have the least effect. Why do we consider wetlands as we plan this project? Wetlands are a valuable resource to our environment. They can help to moderate stormwater flows by slowing down and retaining floodwater during periods of rain. They can help to minimize flooding downstream and to clean the water of material such as dirt and oil. Wetlands can also provide vital habitat for many plants and animals. Because of this, Federal Executive Order 11990 of 1978 requires that all federal agencies, as they carry out specific agency responsibilities, consider wetland protection as an important part of their policies. This includes minimizing the destruction, loss, or degradation of wetlands, and preserving and enhancing the natural beneficial values of wetlands. The US Department of Transportation (USDOT) seeks to assure the protection, preservation, and enhancement of the nation’s wetlands to the fullest extent practicable during the planning, construction, and operation of transportation facilities and projects (DOT Order 5660.1A). WSDOT projects with federal INTRODUCTION Renton Nickel Improvement Project 20 Wetland Discipline Report funding are subject to this order, including the Renton Nickel Improvement Project. What are the key points of this report? This report presents the following key points: The methods used for this project are consistent with federal, state, and local regulations pertaining to wetlands. Wetlands do occur within the study area and generally have been disturbed to some extent by development, including the construction of I-405, SR 167, and commercial and residential development in the surrounding area. There are 19.40 acres of wetlands in the Renton Nickel Improvement Project study area. The majority of the wetlands are dominated by emergent or scrub-shrub vegetation, and they are considered low value, providing relatively little function other than the ability to moderate floodwaters and remove sediment. We have designed the project to avoid and minimize negative effects on wetlands as well as implemented measures to create and enhance vital wetland resources in the study area. The design team worked with the I-405 Team to make design changes to avoid or minimize effects to wetlands and their buffers. These avoidance and minimization measures included using retaining walls and locating stormwater facilities to minimize encroachment into wetlands. Not all effects could be avoided, because some of the wetlands are located immediately adjacent to the existing roadway in areas where the roadway needs to be widened. The project will result in unavoidable negative effects to 1.66 acres of wetland. The project will fill or temporarily disturb an estimated total 2.30 acres of wetland. This represents 12 percent of the wetlands identified within the study area. Of this total, 0.64 acre will be temporarily disturbed during construction. Overall, the majority of wetlands are lower value wetlands because of their proximity to, and association with, I-405 and SR 167. The wetlands within the study area have been INTRODUCTION Renton Nickel Improvement Project Wetland Discipline Report 21 disturbed to some extent by development including the construction of I-405, SR 167, and the surrounding area. Consequently, the wetlands’ ability to provide beneficial functions has been compromised. Some of the larger wetlands that will be affected have forested areas or are associated with a stream, which will result in a loss of general wildlife habitat and fish habitat within the study area. Because of its size and topographic location, the wetland adjacent to SR 167 (Wetland 25.0L) is the highest value wetland that will be affected. Unavoidable negative effects will be mitigated per federal, state, and local regulations. This project is participating in the development and design of the Springbrook Creek Habitat and Wetland Mitigation Bank. Renton Nickel Improvement Project 22 Wetland Discipline Report EXISTING CONDITIONS What is the study area for wetlands and how did we define it? We identified the study area based on the anticipated construction footprint of the Renton Nickel Improvement Project. The construction footprint is defined as areas affected by proposed improvements to I-405 and SR 167 in addition to those areas affected by other necessary project elements, such as stormwater treatment facilities, noise walls, and surface street improvements. We surveyed for wetlands within a study area that includes existing Washington State Department of Transportation (WSDOT) right-of-way between I-5 and SR 169 and along SR 167 between I-405 and South 180th Street. The study area also includes parcels beyond the right- of-way between SR 167 and East Valley Road and in the vicinity of Talbot and Benson Roads where other improvements will occur. What regulations govern project activities in wetlands? Numerous federal, state, and local regulations govern development and other activities in or near wetlands. Four agencies have primary jurisdiction over wetlands in the Renton Nickel Improvement Project study area: Federal: U.S. Army Corps of Engineers (Corps) State: Washington State Department of Ecology (Ecology) Local: City of Tukwila and City of Renton The federal Clean Water Act (CWA) is the principal piece of legislation that regulates activities that may affect wetlands. The CWA grants both the Corps and a designated state agency (Ecology in Washington) the authority to regulate certain activities in wetlands and other types of water bodies. At the local (city) level, Washington State’s Growth Management Act (GMA) requires that wetlands be protected under the local zoning code and/or other regulations that have been developed specific to the management of wetlands and other environmentally critical areas. EXISTING CONDITIONS Renton Nickel Improvement Project Wetland Discipline Report 23 In addition to oversight by these agencies, WSDOT and/or the Federal Highway Administration (FHWA) are obligated to consider wetland protection and to minimize the destruction, loss, or degradation of wetlands as a result of several other orders, rules, and agreements including: Federal Executive Order 11990 of 1978, Department Of Transportation Order 5660.1A (FHWA) State of Washington Executive Order 89-10, Protection of Wetlands (WSDOT) Memorandum of Agreement between WSDOT and Ecology (1993) (WSDOT) Coordination with resource, regulatory, or jurisdictional agencies does not commonly occur at this stage of the environmental review process. The Corps will verify the delineated wetland boundaries during the permitting stage of the Renton Nickel Improvement Project. What existing information is there for wetlands in the study area? Both the Ecology and Corps delineation manuals require the I-405 Team to conduct a review of existing information before proceeding with the necessary fieldwork. Most data were produced by a Geographic Information System (GIS) developed by WSDOT for the Renton Nickel Improvement Project. There are also a variety of resources available for review in the public domain that can help identify if wetlands have a high potential to occur in a particular geographic area. For the Renton Nickel Improvement Project study area, we reviewed several sources of wetland information including recent aerial photographs of the study area, the National Wetland Inventory (NWI),1 King County Sensitive Areas Map Folio,2 Draft City of Tukwila Wetland/Watercourse 1 USFWS, 1987 and 1988. 2 King County, 1990. EXISTING CONDITIONS Renton Nickel Improvement Project 24 Wetland Discipline Report Buffer Map,3 Renton’s Critical Areas Inventory,4 and WDFW Priority Habitats and Species database. We obtained additional information about the location of known hydric soils by using maps published by the U.S. Soil Conservation Service, now known as the Natural Resources Conservation Service (NRCS).5 These resources indicated a high likelihood that wetlands occur in the study area. We identified the following wetland areas during the review of available existing information. Two unnamed wetlands associated with Gilliam Creek, located south of the I-5 northbound to I-405 northbound ramp and west of 61st Avenue South, were identified by the City of Tukwila draft wetland inventory. A system of several wetlands associated with Springbrook Creek, located south of I-405, between West Valley Highway and SR 167. These wetlands comprise 26.6 acres. The City of Renton wetland inventory describes them as “Longacres”. A 3-acre wetland located between I-405 and SE 16th Street, and east of Springbrook Creek. The City of Renton wetland inventory identifies the wetland as “16th Street”. A 1-acre wetland located between Talbot Road and Benson Road, south of the Sam’s Club warehouse store. The City of Renton wetland inventory identifies the wetland as “Puget Wetland”. A 65-acre wetland located east of SR 167, between I-405 and South 43rd Street. The City of Renton wetland inventory identifies the wetland as “Panther Creek.” The wetland inventory describes the Panther Creek wetland as the third highest rated wetland in the City of Renton. Two wetlands located between SW 19th Street and SW 23rd Street to the north and south, 3 City of Tukwila, 2004. 4 City of Renton, 1992. 5 Soil Survey of King County Area, Washington, Snyder et al., 1973. EXISTING CONDITIONS Renton Nickel Improvement Project Wetland Discipline Report 25 and between Lind Avenue SW and East Valley Road to the west and east, respectively. The wetlands are comprised of 24 acres. The City of Renton wetland inventory identifies them as “East Valley B”. A series of eight wetlands located south of SW 23rd Street, between Lind Avenue SE and East Valley Road. The wetlands are a total of 11.74 acres. The City of Renton wetland inventory identifies them as “East Valley C”. Most of the mapped wetlands do not occur within the study area, but three groups of wetlands, the two Gilliam Creek wetlands, “Panther Creek” wetland, and the “Puget Western” wetland occur within the study area and these wetlands were subject to further investigation. In addition to known mapped wetlands, the NRCS has identified one soil unit (Seattle muck) in the study area that is classified as a hydric soil. The other soil units mapped in the study area by the NRCS (Alderwood gravelly sandy loam, Everett gravelly sandy loam, Kitsap silt loam, Ragnar fine sandy loam, and urban land) are not categorized as hydric soils, but the NRCS has identified that these soil types can contain small areas of hydric soils within the larger soil unit. As a result, specific areas were not excluded from the field investigation based solely on soil conditions. How did we identify wetland boundaries in the field? After completing a review of the background information, field studies were conducted for areas that were identified as having a high likelihood of containing wetlands. The field studies involved the I-405 Team walking the areas within the project footprint and marking wetland boundaries with colored flagging. After each wetland was delineated, professional surveyors located the wetland boundaries, and the survey information was entered into WSDOT’s GIS database. After completion of the surveying and mapping, the same team members who conducted the field study reviewed the maps for accuracy. The I-405 Team conducted the wetland field study for the Renton Nickel Improvement Project between late December 2004 and early March 2005. In Washington State, federal, state, and local regulations require that biologists conduct wetland studies using a single, What makes a soil hydric? Soil formed under saturation, flooding, or ponding long enough during the growing season to develop anaerobic (oxygen- deprived) conditions in the upper layer of the soil. What do we mean by wetland delineation? The identification and flagging of wetland boundaries is commonly referred to as “delineating wetlands” in scientific writing and regulatory documents. EXISTING CONDITIONS Renton Nickel Improvement Project 26 Wetland Discipline Report common study methodology developed by the Corps. The Corps of Engineers Wetlands Delineation Manual6 describes this methodology and it must be followed for all wetland studies conducted where the Corps issues the wetland permits. In 1997, Ecology published the Washington State Wetlands Identification and Delineation Manual.7 State and local agencies use this manual in conjunction with the implementation of state Shoreline Management Act (SMA) and GMA- related regulations. The procedures for wetland studies described in Ecology’s 1997 manual are consistent with the 1987 Corps method. What qualifies an area as a “wetland” under the delineation manuals? The Corps and Ecology delineation manuals require the presence of three fundamental characteristics for an area to be delineated as wetland as illustrated in the circle graphic to the left: (1) wetland hydrology (the presence of water during a portion of the annual growing season), (2) hydric soils (soils that develop anaerobic conditions under persistently wet conditions), and (3) hydrophytic vegetation (vegetation that is able to grow and thrive under wet soil conditions). Field indicators of these three characteristics must be present to make a positive wetland determination. Water is an essential element of wetland areas. The wetland delineation manuals require that water be present on a persistent basis in order for wetlands to exist; however, the area does not have to be flooded and water does not have to be present throughout the entire year, as illustrated in Exhibit 10. Under certain conditions, areas where groundwater occurs within the root zone for only about two consecutive weeks each year can meet the requirements for wetland hydrology. 6 Environmental Laboratory, 1987 7 Ecology, 1997 EXISTING CONDITIONS Renton Nickel Improvement Project Wetland Discipline Report 27 Exhibit 10. Presence of Water Relative to the Root Zone in Wetland and Upland Areas To be considered a wetland, an area must have hydric soils. Wetland soils exhibit certain characteristics that biologists can observe in the field. Hydric soils are often dark in color. The dark color is often a result of persistent saturation by water, or flooding for long periods of time. The wetland delineation manuals require that water- tolerant (hydrophytic) plants must be prevalent to meet the jurisdictional definition of “wetland”. Most plants require air around their roots to grow properly. Under typical conditions, the air that normally occurs in spaces between soil particles is sufficient to promote healthy and vigorous growth. In wetlands, however, the space between soil particles are, at some point, saturated with water and air, limiting or excluding air. Hydrophytic plants are generally defined as plants that have specific adaptations that allow them to grow under persistently wet conditions, where saturation limits air in the root zones for all or some of the annual growing season. The USFWS has published the National List of Vascular Plant Species that Occur in Wetlands,8 which is a list of what plant species are known or likely to be present in wetlands. The I-405 Team identified hydrophytic plants based on this list. 8 U.S. Department of the Interior, 1997 EXISTING CONDITIONS Renton Nickel Improvement Project 28 Wetland Discipline Report How did we characterize wetlands in the study area? Wetlands were classified in the study area according to the Cowardin classification system.9 This system, published in 1979 by a team of USFWS scientists led by L.M. Cowardin, bases the classification of wetlands on their physical characteristics, such as the general type of vegetation in the wetland (trees, shrubs, grass or forbs, etc.) and how much, and where, water is present in the wetland. The Cowardin classification system classifies every known wetland type that occurs throughout the United States. Relatively few types of wetlands are present in the Renton Nickel Improvement Project study area. Specifically, the I-405 Team assigned each wetland to one of the following Cowardin classes: palustrine emergent (PEM), palustrine scrub-shrub (PSS), palustrine forested (PFO), and palustrine aquatic bed (PAB). These terms are defined in the Glossary. Exhibit 11 illustrates the various wetland types and where they may typically occur in the landscape. Exhibit 11. Types of Wetlands and Their Typical Positions in the Landscape 9 Cowardin et al., 1979. EXISTING CONDITIONS Renton Nickel Improvement Project Wetland Discipline Report 29 Where are the wetlands in the study area and what are their characteristics? After the review of existing information was completed, the I-405 Team field surveyed the study area to determine if any other wetlands were present. During the site-specific field investigation, the I-405 Team delineated four previously mapped wetlands. The I-405 Team also identified and delineated 25 smaller wetlands that had not been previously mapped as shown in Exhibits 12-A through 12-H. Twenty-nine (29) wetlands totaling 19.40 acres within the study area were delineated for the Renton Nickel Improvement Project. Finding a high number of small, unmapped wetlands is not uncommon in this geographic region (referred to as the Puget Sound trough). High densities of small wetlands are particularly common throughout lower elevation-areas of the Lake Washington watershed. Wetlands identified in the study area are typically associated with streams, hillside seeps, or drainage ditches. Drainage ditches that receive road runoff and convey stormwater are considered to be wetlands if they: meet the three wetland criteria, have a downstream connection seep or stream-associated wetland, or appear to have been constructed in an historical wetland. Wetlands are described in location sequence from south to north. Each wetland identified in the field was assigned a number based on its milepost (MP) location within the study area, starting with MP 0.0 at the southern end of the study area at the intersection with I-5 and extending east to MP 4.0. Wetlands adjacent to SR 167 are between MP 24.6 and MP 26.3. The wetland number also includes “L” if the wetland is located on the left (north) side of I-405 or the left (west) side of SR 167. The wetland number includes “R” if it is located on the right (south) side of I-405 or the right (east) side of SR 167. For example, a wetland found at the midpoint between MP 2 and MP 3 on the left side of I-405 would be Wetland 2.5L. Emergent wetland near Talbot Road Aquatic bed wetland near Green River EXISTING CONDITIONS Renton Nickel Improvement Project 30 Wetland Discipline Report Exhibit 12-A. Renton Nickel Improvement Project Wetlands EXISTING CONDITIONS Renton Nickel Improvement Project Wetland Discipline Report 31 Exhibit 12-B. Renton Nickel Improvement Project Wetlands EXISTING CONDITIONS Renton Nickel Improvement Project 32 Wetland Discipline Report Exhibit 12-C. Renton Nickel Improvement Project Wetlands EXISTING CONDITIONS Renton Nickel Improvement Project Wetland Discipline Report 33 Exhibit 12-D. Renton Nickel Improvement Project Wetlands EXISTING CONDITIONS Renton Nickel Improvement Project 34 Wetland Discipline Report Exhibit 12-E. Renton Nickel Improvement Project Wetlands EXISTING CONDITIONS Renton Nickel Improvement Project Wetland Discipline Report 35 Exhibit 12-F. Renton Nickel Improvement Project Wetlands EXISTING CONDITIONS Renton Nickel Improvement Project 36 Wetland Discipline Report Exhibit 12-G. Renton Nickel Improvement Project Wetlands EXISTING CONDITIONS Renton Nickel Improvement Project Wetland Discipline Report 37 Exhibit 12-H. Renton Nickel Improvement Project Wetlands EXISTING CONDITIONS Renton Nickel Improvement Project 38 Wetland Discipline Report Because I-405 intersects several waterbodies, the study area also crosses the Green River, Gilliam Creek, Cottage Creek, Springbrook Creek, Panther Creek, Rolling Hills Creek, Thunder Hills Creek, the Cedar River, and several unnamed tributaries. The study area also spans three different drainage basins: Green River, Springbrook Creek, and Cedar River. The Green River basin contains 14 wetlands covering 4.01 acres. The Springbrook Creek basin contains the highest number of wetlands and the largest area of wetlands with 15 wetlands covering 15.39 acres. No wetlands occur in the Cedar River basin that lies within the study area. Green River basin Wetlands in the study area within the Green River basin receive water from Gilliam Creek, surface water drainage, and groundwater. The majority of wetlands are roadside ditches dominated by bentgrass, common cattail, and soft rush. These wetlands receive road runoff and typically discharge to a catchbasin or culvert. Exhibit 13 summarizes the wetlands in the Green River basin. The wetland areas shown represent the total area of wetland delineated, not just those areas that will be affected by the roadway improvements. Two of the 14 wetlands in the basin wetlands 0.15R and 0.3R are associated with Gilliam Creek. Wetland 0.3R is 1.29 acres and contains a large forested topographic depression that is ponded year-round. It is dominated by black cottonwood and willow. Wetland 0.6L is a 0.17-acre scrub-shrub wetland that receives water from Cottage Creek, a tributary of Gilliam Creek. This wetland is dominated by willow and black cottonwood and also contains common cattail and reed canarygrass. Water from this wetland flows into a pipe that runs beneath I-405 and connects with Gilliam Creek, which flows into the Green River. Scrub-shrub wetland associated with Thunder Hills Creek Forested wetland along I-405 EXISTING CONDITIONS Renton Nickel Improvement Project Wetland Discipline Report 39 Exhibit 13. Summary of Wetlands Located within the Green River Basin Wetland Name Size (acres) Cowardin Classification1 Wetland Characteristics 0.15R 0.52 Emergent Depression associated with Gilliam Creek that is dominated by reed canarygrass; located south of I-5 northbound to I-405 northbound ramp. 0.1L 0.11 Emergent Narrow swale dominated by reed canarygrass and soft rush; located east of I-405 to I-5 northbound ramp. 0.1R 0.05 Emergent Isolated depression dominated by reed canarygrass, soft rush, bentgrass; located in the southeast portion of the I-405/I-5 interchange. 0.25M 0.07 Emergent Maintained swale dominated by reed canarygrass; located between I-405 northbound lanes and the HOV on-ramp to I-5 north. 0.3R 1.29 Forested Ponded depression associated with Gilliam Creek dominated by willow and red cedar; located south of I-5 north to I-405 north ramp and west of 61st Avenue S. 0.4L 0.11 Emergent Ditch-associated wetland dominated by reed canarygrass, common cattail, and bentgrass. 0.5L 0.05 Emergent Ditch-associated wetland dominated by reed canarygrass and soft rush. 0.6L 0.17 Scrub-shrub Narrow depressional wetland that receives flow from Cottage Creek culverts south of Southcenter Blvd; dominated by reed canarygrass, black cottonwood, willow, and soft rush. 0.7R 0.03 Forested Narrow depression at base of slope; dominated by soft rush, black cottonwood, and Himalayan blackberry; located adjacent to Gilliam Creek and west of Christensen Road. 0.88R 0.02 Emergent Depression dominated by reed canarygrass and soft rush; located west of the southbound SR 181 to northbound I-405 interchange. 0.92R 0.09 Emergent Ditch-associated wetland dominated by reed canarygrass, soft rush, and red fescue; located within the southbound SR 181 to northbound I-405 interchange. 0.94L 0.48 Scrub-shrub Depression dominated by red-osier dogwood, red alder, and bluegrass, discharges to Green River; located north of Southcenter Blvd, west of Interurban Ave. 0.99L 0.01 Emergent Depression dominated by reed canarygrass, common cattail, and Himalayan blackberry; located southeast of SR 181/SW Grady Way intersection. 0.9R 1.01 Aquatic bed Depression with scrub-shrub wetland along perimeter dominated by willow, located near the I-405 and SR 181 southbound interchange and east of the Green River. TOTAL 4.01 EXISTING CONDITIONS Renton Nickel Improvement Project 40 Wetland Discipline Report Springbrook Creek basin The Springbrook Creek basin covers approximately two-thirds of the study area and contains 15 wetlands with a combined area of 15.39 acres. These wetlands receive water from the creek and its tributaries, surface water, and a high groundwater table. Exhibit 14 summarizes the wetlands in the Springbrook Creek basin. The wetland areas shown represent the total area of wetland delineated, not just those areas that will be affected by the roadway improvements. Five of the wetlands are located in the cloverleaf interchange of I-405 and SR 167 and convey stormwater runoff. These are PEM wetlands dominated by reed canarygrass, soft rush, and bentgrass. Two wetlands (Wetland 1.57L and 1.6R) are scrub-shrub wetlands associated directly with Springbrook Creek as it flows northward under I-405 near Oakesdale Avenue SW. These disturbed wetlands are dominated by willow and have a concrete wall as their eastern boundary. At the eastern end of the study area, two tributaries to Springbrook Creek, Thunder Hills Creek, and Rolling Hills Creek, enter the study area and bring flow to several roadside ditches and topographical depressions. Wetland 2.9L is a 1.06-acre scrub-shrub wetland that is dominated by common cattail, reed canarygrass, and willow and receives water from Thunder Hills Creek. The majority of the SR 167 portion in the study area contains wetlands on both sides that are associated with Panther Creek, another tributary to Springbrook Creek. Wetland 24.7R is part of the Panther Creek wetlands located east of SR 167. This complex covers approximately 65 acres and is dominated by black cottonwood, red osier dogwood, Douglas spirea, willow, reed canarygrass, and common cattail. The I-405 Team delineated the portion (6.98 acres) of the Panther Creek wetlands within the study area. Wetland 25.0L (5.88 acres) extends along the west side of SR 167 and is a long, narrow forested wetland. It receives flow from the Panther Creek wetland complex through multiple culverts under SR 167. Some of the culverts may be blocked, but flow patterns in this area are currently undetermined. EXISTING CONDITIONS Renton Nickel Improvement Project Wetland Discipline Report 41 Exhibit 14. Summary of Wetlands Located within the Springbrook Creek Basin Wetland Name Size (acres) Cowardin Classification1 Wetland Characteristics 1.57L 0.13 Scrub-shrub Riparian wetland associated with Springbrook Creek and dominated by willow and Himalayan blackberry; located north of I-405 southbound lanes and west of Oakesdale Ave. SW. 1.6R 0.16 Scrub-shrub Riparian wetland associated with Springbrook Creek and dominated by willow and Himalayan blackberry; located south of I-405 northbound lanes, and west of Oakesdale Ave. SW. 1.7R 0.46 Scrub-shrub Long ditch-associated wetland dominated by reed canarygrass and willow. 2.23L 0.04 Emergent Depression dominated by bentgrass and reed canarygrass; located in I-405/SR 167 cloverleaf interchange. 2.25R 0.05 Emergent Ditch-associated wetland dominated by bentgrass and velvetgrass; located in I-405/SR 167 cloverleaf interchange. 2.2R 0.10 Scrub-shrub Ditch-associated wetland dominated by reed canarygrass and Himalayan blackberry; located south of northbound I-405 to southbound SR 167 ramp. 2.31R 0.01 Emergent Depression dominated by reed canarygrass; located in I-405/SR 167 cloverleaf interchange. 2.6L 0.02 Emergent Ditch-associated wetland dominated by bentgrass and reed canarygrass; located at I-405/SR 167 cloverleaf interchange. 2.7L 0.07 Emergent Depression dominated by soft rush and bentgrass; located west of Talbot Road and south of One Renton Place. 2.81L 0.03 Emergent Isolated depression dominated by reed canarygrass and Himalayan blackberry; located east of Benson Road. 2.9L 1.07 Scrub-shrub Depression and seep wetland dominated by reed canarygrass, common cattail, willow, and Himalayan blackberry; located between Talbot and Benson Roads. Thunder Hills Creek flows south through and adjacent to the wetland. 24.7R 6.98 Forested Large complex associated with Panther Creek dominated by black cottonwood, willow, common cattail, and reed canarygrass; located east of SR 167 and south of I-405. 25.0L 5.88 Scrub-shrub Narrow depression dominated by willow, Himalayan blackberry, and reed canarygrass; located between SR 167 and East Valley Rd 25.7L 0.30 Scrub-shrub Ditch-associated wetland dominated by reed canarygrass; located between SR 167 and East Valley Rd. 25.9L 0.09 Forested Long, narrow depression dominated by black cottonwood, willow, Himalayan blackberry, and reed canarygrass. Receives westerly flow from Panther Creek complex through the culvert at 34th Street under SR 167. TOTAL 15.39 EXISTING CONDITIONS Renton Nickel Improvement Project 42 Wetland Discipline Report How did we evaluate wetlands and what rating systems did we use? Both state and local resource agencies rate or categorize wetlands according to their relative rarity or importance. The agencies use these ratings to determine buffer requirements and appropriate replacement ratios for mitigation purposes. Wetland buffers are areas that surround a wetland and reduce adverse effects to the resource from adjacent development. At the state level, wetlands are categorized by applying a rating system developed by Ecology.10 Ecology developed this system to differentiate wetlands based on their sensitivity to disturbance, their significance in the watershed, their rarity, the ability to replace them, and the beneficial functions they provide to society. Wetlands are categorized according to these criteria: Category I wetlands represent a unique or rare wetland type; or are more sensitive to disturbance; or are relatively undisturbed and contain ecological attributes that are impossible to replace within a human lifetime. Category II wetlands are difficult, though not impossible, to replace, and provide high levels of some functions. Category III wetlands have a moderate level of function. They have been disturbed in some ways, and are often less diverse or more isolated from other natural resources in the landscape than Category II wetlands. Category IV wetlands have the lowest levels of functions and are often heavily disturbed. The Ecology rating system was used to rank wetlands in the Renton Nickel Improvement Project study area. The Ecology rating system requires the user to collect specific information about the wetland in a step-by- step process. The process analyzes and rates three major functions: flood and erosion control, water quality improvement, and wildlife habitat. Ratings are based on a point system where points are given if a 10 Washington State Wetland Rating System for Western Washington – Revised. Hruby, 2004. Exhibit 15. Point Totals for Higher and Lower Value Wetlands Based on Ecology Rating System EXISTING CONDITIONS Renton Nickel Improvement Project Wetland Discipline Report 43 wetland meets specific criteria related to the wetland’s potential and opportunity to provide certain benefits. Exhibit 15 illustrates a comparison of the point totals between an example high-value wetland and a typical lower value wetland found in the Renton Nickel Improvement Project study area. Local governments have also created systems for rating wetlands that allow them to prioritize wetland protection. The local rating system is typically based on the state rating system, but the local system also considers some criteria specific to that jurisdiction, such as rarity within the local area. The Cities of Tukwila and Renton have their own sensitive areas ordinances that include wetland classification systems. The study area wetlands were also evaluated under each city’s respective municipal code. How are the wetlands in the study area ranked? We rated wetlands under two rating systems: 1) the state system developed by Ecology, and 2) the city rating system in which the wetland occurs (i.e., the City of Tukwila or the City of Renton). The rating systems are based on different factors and characteristics of the wetland. Thus, some wetlands may be more valuable and have a higher rating under the city rating system as compared to the state system. For example, Wetland 24.7R is associated with Panther Creek and is considered a Category II wetland under the state rating system and a Category I under the City of Renton rating system. This is because the City of Renton has identified this wetland complex as having local significance and/or regional value. All wetlands with this status are considered Category I under the Renton City rating system. Using Ecology’s rating system, the I-405 Team categorized 15 of the 29 total wetlands (52 percent) that occur in the study area as Category IV wetlands, the lowest-value class of wetlands described using the Ecology rating system.11 We ranked 13 as Category III wetlands and classified one as a Category II wetland. No Category I wetlands occur within the study area. 11 Hruby, 2004. EXISTING CONDITIONS Renton Nickel Improvement Project 44 Wetland Discipline Report Exhibit 16 summarizes the state and local ratings of wetlands in the study area. Exhibit 16. Wetland Ratings in Study Area Wetland Name Area (acres) Cowardin Classification State Rating (Ecology) Local Rating1 0.15R 0.52 Emergent III Tukwila - 2 0.1L 0.11 Emergent IV Tukwila - 3 0.1R 0.05 Emergent IV Tukwila - 3 0.25M 0.07 Emergent IV Tukwila - 3 0.3R 1.29 Forested III Tukwila - 2 0.4L 0.11 Emergent IV Tukwila - 3 0.5L 0.05 Emergent IV Tukwila - 3 0.6L 0.17 Scrub-shrub IV Tukwila - 3 0.7R 0.03 Forested IV Tukwila - NR 0.88R 0.02 Emergent IV Tukwila - NR 0.92R 0.09 Emergent IV Tukwila - 3 0.94L 0.48 Scrub-shrub III Tukwila - 2 0.99L 0.01 Emergent IV Tukwila - NR 0.9R 1.01 Aquatic bed III Tukwila - 2 1.57L 0.13 Scrub-shrub III Renton - 3 1.6R 0.16 Scrub-shrub III Renton - 3 1.7R 0.46 Scrub-shrub III Renton - 3 2.23L 0.04 Emergent IV Renton - NR 2.25R 0.05 Emergent IV Renton - 3 2.2R 0.10 Scrub-shrub III Renton - 3 2.31R 0.01 Emergent IV Renton - NR 2.6L 0.02 Emergent IV Renton - NR 2.7L 0.07 Emergent IV Renton - 3 2.81L 0.03 Emergent III Renton - NR 2.9L 1.07 Scrub-shrub III Renton - 3 24.7R 6.98 Forested II Renton - 1 25.0L 5.88 Scrub-shrub III Renton - 3 25.7L 0.30 Scrub-shrub III Renton - 3 25.9L 0.09 Forested III Renton - 3 TOTAL 19.40 1. City of Renton - Category 3 wetlands less than 2,200 square feet (0.05 acre) are exempt from regulation under Renton Municipal Code Critical Areas Regulations (RMC 4-3-50 B(7)). These wetlands are specified as “NR” in the above exhibit. City of Tukwila - Wetlands 1,000 square feet (0.02 acre) and less that do not meet any wetland rating criteria are exempt from requirements of the Tukwila Municipal Code Chapter 18.45 (TMC 18.45.180A). These wetlands are specified as “NR” in the above exhibit. EXISTING CONDITIONS Renton Nickel Improvement Project Wetland Discipline Report 45 According to the Tukwila Environmentally Sensitive Areas code, half of the wetlands (7 of 14) occurring in the portion of the study area within Tukwila are Type 3 wetlands. Wetlands 0.15R, 0.3R, 0.9R, and 0.94L are Type 2 wetlands because they are connected to a watercourse that contains salmonids, or are larger than one acre. There are no Type 1 wetlands in the study area within Tukwila. The City of Tukwila considers the remaining three wetlands exempt from regulations because they are 1,000 square feet or less. Of the 15 wetlands in the portion of the study area occurring in the City of Renton, 10 are considered Category 3 wetlands according to the Renton Environmental Regulations. These wetlands have undergone human-related hydrologic alterations such as ditching or channelization, thus qualifying them as Category 3. One wetland (Wetland 24.7R associated with Panther Creek) is considered a Category 1 because it is over 10 acres of wetland. The City of Renton considers the remaining three wetlands exempt from regulations because they are Category 3 wetlands less than 2,200 square feet. How did we assess the wetland functions and values? WSDOT has developed a qualitative method of assessing the functions, or benefits, provided by wetlands along linear corridors. The method is called the Wetland Functions Characterization Tool for Linear Projects12 and it provides a rapid and consistent qualitative assessment of wetland functions using best professional judgment. The WSDOT method assesses the following functions: Flood flow alteration Sediment removal Nutrient and toxicant removal Erosion control and shoreline stabilization Organic matter production and its export General habitat suitability Aquatic invertebrate habitat 12 Null et al., 2000. EXISTING CONDITIONS Renton Nickel Improvement Project 46 Wetland Discipline Report Amphibian habitat Wetland-associated mammal habitat Wetland-associated bird habitat General fish habitat Native plant richness Educational or scientific value Uniqueness and heritage Conditions of the study area wetlands were documented during the field investigations on data forms in Appendix A. Positive answers to several questions on the data forms generally indicate the presence of factors that are important in order for the wetland to provide a particular function or value. Best professional judgment was then used to determine if that particular function is likely or not likely to be performed by each wetland. What functions do study area wetlands provide? Functions and values of wetlands in the study area are summarized in Exhibit 17. Twenty (20) of the 29 wetlands (69 percent) within the study area are relatively small (less than one-third acre). The two largest wetlands are located in the Springbrook Creek basin and are Wetland 24.7R and Wetland 25.0L, 6.97 acres and 5.87 acres, respectively. Of the nine wetlands one-third acre or larger, four are located within the Green River basin and the other five are located in the Springbrook Creek basin. However, the Springbrook basin contains the majority of wetland area in the study area, 15.39 acres compared to 4.01 acres in the Green River basin. Twenty-five (25) of the 29 wetlands (86 percent) are dominated by emergent and/or scrub-shrub vegetation. Since forested wetlands are generally larger and located beyond the maintained road right- of-way, there are only four wetlands within the study area (10 percent)classified as forested per the Cowardin system. EXISTING CONDITIONS Renton Nickel Improvement Project Wetland Discipline Report 47 Exhibit 17. Wetland Functions and Values in the Study Area Wetland Identifier Area (acres) Cowardin Classification Flood Flow Alteration Sediment Removal Nutrient & Toxicant Removal Erosion Control & Shoreline Stabilization Production of Organic Matter and its Export General Habitat Suitability Habitat for Aquatic Invertebrates Habitat for Amphibians Habitat for Wetland-Associated Mammals Habitat for Wetland-Associated Birds General Fish Habitat Native Plant Richness Educational or Scientific Value Uniqueness and Heritage 0.15R 0.52 Emergent 9 9 9 9 9 9 9 9 0.1L 0.11 Emergent 9 9 9 9 0.1R 0.05 Emergent 9 9 9 0.25M 0.07 Emergent 9 9 9 0.3R 1.29 Forested 9 9 9 9 9 9 9 9 9 0.4L 0.11 Emergent 9 9 9 0.5L 0.05 Emergent 9 9 9 9 9 0.6L 0.17 Scrub-shrub 9 9 9 9 9 9 0.7R 0.03 Forested 9 9 9 9 0.88R 0.02 Emergent 9 9 9 9 9 0.92R 0.09 Emergent 9 9 9 9 0.94L 0.48 Scrub-shrub 9 9 9 9 9 9 0.99L 0.01 Emergent 9 9 0.9R 1.01 Aquatic bed 9 9 9 9 9 9 9 9 1.57L 0.13 Scrub-shrub 9 9 9 9 9 9 1.6R 0.16 Scrub-shrub 9 9 9 9 9 9 9 1.7R 0.46 Scrub-shrub 9 9 9 9 9 2.23L 0.04 Emergent 9 9 2.25R 0.05 Emergent 9 9 9 2.2R 0.10 Scrub-shrub 9 9 9 9 2.31R 0.01 Emergent 9 9 2.6L 0.02 Emergent 9 9 2.7L 0.07 Emergent 9 9 2.81L 0.03 Emergent 9 9 9 2.9L 1.07 Scrub-shrub 9 9 9 9 9 9 9 24.7R 6.98 Forested 9 9 9 9 9 9 9 9 9 9 9 9 25.0L 5.88 Scrub-shrub 9 9 9 9 9 9 9 9 9 25.7L 0.30 Scrub-shrub 9 9 9 9 9 25.9L 0.09 Forested 9 9 9 9 9 9 9 9 9 9 9 = function likely provided by this wetland EXISTING CONDITIONS Renton Nickel Improvement Project 48 Wetland Discipline Report Large wetlands in the study area are typically located in low-lying areas and associated with streams. Small wetlands tend to be located in small closed topographic depressions, or are hydrologically connected (linked to or associated with a water source) to hillside seeps, or roadside drainage ditches. Because large wetlands have more capacity for capturing stormwater flows, improving water quality, and providing a variety of habitats for wildlife, they are more likely to provide a higher number and higher value of beneficial functions than smaller wetlands. The urban growth area encompasses the study area, and existing road rights-of-way comprise most of the study area. Within it, the wetlands have been disturbed to some extent by development, including the construction of I-405, SR 167, and commercial or residential development in the surrounding area. Consequently, the wetlands are compromised in their ability to provide functions and values. More than one-half of the wetlands were found to have the potential to provide valuable stormwater management functions including: flood flow alteration, sediment removal, nutrient and toxicant removal, and erosion control. Some of these areas have constricted outlets and dense woody vegetation, slowing floodwaters during storm events. Most wetlands have dense herbaceous vegetation that can remove sediment and toxicants present in road runoff. Approximately one-third of the total number of wetlands are likely to provide functions related to general habitat, habitat for amphibians, wetland- associated mammals and/or wetland-associated birds, or native plant richness. These wetlands may have multiple vegetation classes, seasonal or permanent open water, or have evidence of wildlife use such as dens, tracks, scat, or gnawed stumps. Six of the wetlands likely provide general value as fish habitat (Wetlands 0.15R, 0.3R, 1.57L. 1.6R. 25.0L, and Wetland 24.7R (Panther Creek)). Wetland 24.7R likely provides uniqueness and heritage value and wetland 0.94L likely provides native plant richness. The majority of wetlands in the study area are either not publicly owned or occur in WSDOT right-of-way, which limits their educational and recreational uses. Renton Nickel Improvement Project Wetland Discipline Report 49 POTENTIAL EFFECTS How did we calculate wetland areas and effects? The wetland areas were surveyed and mapped based on the boundaries identified by the I-405 Team in the field. Engineers reviewed the wetland mapping and compared it to the project study area footprint. Wetland loss was calculated using computer-aided design (CAD) software. In addition to calculating direct wetland loss as a result of the project, the areas of temporary wetland loss that might occur during construction were also calculated. Effects to wetland buffers were calculated based on the appropriate local jurisdiction. Will project construction affect wetlands? Permanent effects To build the additional roadway and stormwater facilities, construction will occur in and adjacent to wetlands and their buffers. The project will remove trees and shrubs and convert unpaved areas to paved roadway. This conversion will permanently affect 11 of the 29 identified wetlands totaling 1.66 acres as shown in Exhibit 18. Depending on the wetland location, size, and shape, some wetlands will be completely filled and others will only have a portion filled. Where feasible, modifications to the footprint were made. For example, multiple design changes were made to reduce effects to Wetland 25.0L. When a wetland appeared to be located within the project footprint, engineers changed the footprint to avoid the wetland or, if the wetland could not be avoided, we determined how much wetland area would be lost due to project construction. Filling a portion of a wetland or altering its vegetation can reduce the wetland’s capacity to store stormwater, filter pollutants, protect stream banks from erosion, and provide wildlife habitat. Of the 11 affected wetlands, the project will fill two wetlands completely and ten wetlands partially. The largest wetland in the study area, Wetland 25.0L along SR 167, accounts for 60 percent of the total wetland fill. Wetland 1.7R is a narrow ditch-associated wetland, which accounts for 28 percent of the total affected area. This wetland will be completely filled to allow for the additional northbound lane along I-405. POTENTIAL EFFECTS Renton Nickel Improvement Project 50 Wetland Discipline Report Exhibit 18. Filled or Disturbed Wetlands in the Study Area Filled or Otherwise Disturbed Area Rating Wetland Identifier Area (acres) Temporarily (acres) Permanently (acres) State (Ecology) Local Jurisdiction1 Avoidance and Minimization 0.15R 0.52 - - III Tukwila - 2 Avoided 0.1L 0.11 - - IV Tukwila - 3 Avoided 0.1R 0.05 - - IV Tukwila - 3 Avoided 0.25M 0.07 - - IV Tukwila - 3 Avoided 0.3R 1.29 - - III Tukwila - 2 Avoided 0.4L 0.11 0.01 0.08 IV Tukwila - 3 Unavoidable due to roadway design standards. Retaining wall not viable due to safety concerns. 0.5L 0.05 <0.01 0.05 IV Tukwila - 3 Unavoidable due to roadway design standards. Retaining wall not viable due to safety concerns. 0.6L 0.17 0.01 0.01 IV Tukwila - 3 Unavoidable due to roadway design standards. 0.7R 0.03 - - IV Tukwila - NR Avoided 0.88R 0.02 <0.01 <0.01 IV Tukwila - NR Stormwater intake designed to minimize impacts to wetland. Complete avoidance not feasible. 0.92R 0.09 - - IV Tukwila - 3 Avoided 0.94L 0.48 - - III Tukwila - 2 Avoided 0.99L 0.01 - - IV Tukwila - NR Avoided 0.9R 1.01 0.01 0.01 III Tukwila - 2 Stormwater outfall designed to minimize impacts to wetland. 1.57L 0.13 - <0.01 III Renton - 3 Unavoidable impacts minimized by bridge design. 1.6R 0.16 <0.01 <0.01 III Renton - 3 Unavoidable impacts minimized by bridge design. 1.7R 0.46 - 0.46 III Renton - 3 Unavoidable due to roadway design standards and to avoid impacts to local business. 2.23L 0.04 - - IV Renton - NR Avoided 1. City of Renton - Category 3 wetlands less than 2,200 square feet are exempt from regulation under Renton Municipal Code Critical Areas Regulations (RMC 4-3-50 B(7)). These wetlands are specified as “NR” in the above exhibit. City of Tukwila - Wetlands 1,000 square feet and less that do not meet any wetland rating criteria are exempt from requirements of the Tukwila Municipal Code Chapter 18.45 (TMC 18.45.180A). These wetlands are specified as “NR” in the above exhibit. POTENTIAL EFFECTS Renton Nickel Improvement Project Wetland Discipline Report 51 Exhibit 18. Filled or Disturbed Wetlands in the Study Area (continued) Filled or Otherwise Disturbed Area Rating Wetland Identifier Area (acres) Temporarily (acres) Permanently (acres) State (Ecology) Local Jurisdiction1 Avoidance and Minimization 2.25R 0.05 - - IV Renton - 3 Avoided 2.2R 0.10 - - III Renton - 3 Avoided 2.31R 0.01 - - IV Renton - NR Avoided 2.6L 0.02 - 0.02 IV Renton - NR Unavoidable due to roadway design standards. 2.7L 0.07 0.01 0.01 IV Renton - 3 Direct impacts minimized by retaining wall, but construction requirements require safety considerations for WSDOT It is not possible to alter the impact line to completely avoid impacts to this wetland. 2.81L 0.03 - - III Renton - NR Avoided 2.9L 1.07 - - III Renton - 3 Avoided 24.7R 6.98 - - II Renton - 1 Avoided 25.0L 5.88 0.56 0.99 III Renton - 3 A retaining wall will be constructed along the entirety of this wetland to avoid and minimize impacts. A new ecology embankment will need to be constructed that will “bump out” the wall an additional ten feet to the west. This additional ten feet is required to meet the flow (head) requirements to allow the ecology embankment to function properly. 25.7L 0.30 - - III Renton - 3 Avoided. 25.9L 0.09 0.01 - III Renton - 3 Unavoidable due to roadway design standards. Retaining wall added to minimize impacts. Totals 19.40 0.64 1.66 1. City of Renton - Category 3 wetlands less than 2,200 square feet are exempt from regulation under Renton Municipal Code Critical Areas Regulations (RMC 4-3-50 B(7)). These wetlands are specified as “NR” in the above exhibit. City of Tukwila - Wetlands 1,000 square feet and less that do not meet any wetland rating criteria are exempt from requirements of the Tukwila Municipal Code Chapter 18.45 (TMC 18.45.180A). These wetlands are specified as “NR” in the above exhibit. POTENTIAL EFFECTS Renton Nickel Improvement Project 52 Wetland Discipline Report Temporary effects To build the additional roadway and stormwater facilities, some construction will take place outside of the permanent infrastructure footprint. Construction equipment may be required to temporarily clear wetland and upland vegetation in the Renton Nickel Improvement Project study area. WSDOT may need to place temporary fill in wetlands and buffers to allow enough space for construction. It is anticipated that 0.64-acre of wetland will be temporarily disturbed during construction activities, including vegetation clearing and the placement of fill material. After the project is complete, these areas will be restored and replanted with appropriate vegetation. WSDOT will develop a project-specific plan before construction to identify how restoration will occur. Construction disturbance will result in a short-term loss of wetland functions. Habitat functions will be temporarily reduced as the planted trees, shrubs, and emergent plants become established. Wetlands where the vegetation is cleared or trimmed will still retain some water quality and quantity function, although at a diminished level until completely reestablished. Erosion and sedimentation caused by project activities will increase the amount of sediment settling within a wetland and reduce the quality of habitat available for invertebrate life and habitat for plants. Additionally, loose sediment will reduce the potential water quality and quantity benefits provided by those wetlands. However, best management practices (BMPs) will be implemented as required in the WSDOT Highway Runoff Manual13 to minimize erosion and sedimentation during construction. Will project operation affect wetlands? No additional effects on wetlands are expected during operation of the Renton Nickel Improvement Project. Some wetlands that occur within the right-of-way are currently affected by the lack of forested upland buffer and the lack of modern stormwater control and management facilities. Wetland areas that occur 13 WSDOT, 2004. POTENTIAL EFFECTS Renton Nickel Improvement Project Wetland Discipline Report 53 within right-of-way that must be kept clear of forested vegetation to meet safety requirements and those wetlands that receive untreated or undertreated stormwater runoff will likely continue to be affected by these conditions. Would the No Build Alternative affect wetlands? The No Build Alternative would have no permanent, temporary, or indirect effects on wetlands in the Renton Nickel Improvement Project study area. No wetland or wetland buffer would be filled or cleared under this alternative, and there would no change to current moderation of stormwater flows or existing wildlife habitat functions. Some wetlands that occur within the right-of-way are currently affected by that lack of forested upland buffer and the lack of modern stormwater control and management facilities. Wetland areas that occur within the areas of the right-of-way that must be kept clear of forested vegetation as a result of safety requirements and those wetlands that receive untreated or under treated stormwater runoff would likely continue to be affected by these conditions. Minor roadway safety improvements would continue to take place. In addition, wetlands in the study area currently receive untreated runoff from stormwater facilities that are not at current treatment levels. Water quality in these wetlands would continue to be affected by sediment transport and erosion. Will this project result in any indirect effects? For wetlands, we consider indirect effects as they relate to the loss of specific wetland functions. There are two primary pathways of indirect effects that would occur as a result of impacts to wetlands for this project. The first type of indirect effect will not occur as a result of the direct impact of an individual wetland, but the effect would occur at a later time than the direct impact. For example, the loss of wetland area will have the direct effect of reducing the habitat area available for wetland-dependent wildlife. The associated indirect effect could be increased competition in the remaining wetlands because of the potential influx of displaced wildlife from the affected wetland. POTENTIAL EFFECTS Renton Nickel Improvement Project 54 Wetland Discipline Report The second type of indirect effect would result from other, wider-ranging alterations from the project. An example of this type of indirect impact is the new impervious surface due to widening the roadways. Even though the new impervious surface may not have direct impacts to wetlands, the new impervious surface could change existing drainage (e.g., by increasing the amount of runoff, decreasing potential infiltration of rainwater, or changing the period that runoff occurs). These changes could subsequently affect hydrology of downgradient wetlands, even wetlands that occur beyond the actual project limits. The likelihood that an indirect effect could occur as a result of the project and the severity of that effect is related to two primary factors: (1) the level of function provided by the affected wetland and (2) the ability of WSDOT to mitigate for the potential impact. The likelihood and severity of indirect effects caused by increased competition among wetland-dependent wildlife would be highest for wetlands with the highest potential wildlife habitat. Similarly, there would be a low likelihood and severity of indirect effects to wetland-dependent wildlife if the wetland had low wildlife habitat function before an action occurred. If there is a relatively high likelihood that an indirect effect would occur, then the severity of the impact should be considered relative to WSDOT’s ability to provide adequate mitigation to offset that impact. To avoid the potential for indirect effects to rise to the level of significance, WSDOT will need to provide project elements that compensate for this loss. If the project resulted in the loss of wetland that provided a high level of function as wetland-dependent wildlife habitat, WSDOT will need to mitigate for these potential effects. Possible mitigation could include the creation of new wetlands or the rehabilitation or enhancement of degraded or existing wetlands. Such mitigation provides new habitat opportunities for wildlife to replace those lost as a result of the indirect effect. What are indirect effects? Indirect effects are defined in the WSDOT Environmental Procedures Manual as the “effect caused by the proposed action that is later in time or farther removed in distance, but still reasonably foreseeable. Indirect effects may include growth-inducing effects and other effects related to induced changes in the pattern of land use, population density or growth rate, and related effects on air and water and other natural systems, including ecosystems.” Were cumulative effects looked at for this discipline? Cumulative effects for this discipline are evaluated in a separate Cumulative Effects Analysis Discipline Report. That report discusses cumulative effects for this project in the areas of Air Quality, Surface Water and Water Quality, Fisheries and Aquatic Habitat, and Wetlands. Cumulative effects for other disciplines were determined to be unnecessary for this project. Renton Nickel Improvement Project Wetland Discipline Report 55 MEASURES TO AVOID OR MINIMIZE PROJECT EFFECTS What has been done to avoid or minimize negative effects on wetlands? The wetland investigations were conducted before a specific design was completed. The I-405 Team reviewed the wetland mapping and compared it to their current footprint of the road improvements. When a wetland appeared to be located within the project study area footprint, engineers changed the footprint to avoid the wetland or, if the wetland could not be avoided, it was determined how much wetland area will be lost due to the project. Then specific design changes were made to avoid or minimize effects to wetlands, as identified in Exhibit 18. In most cases, permanent effects to wetlands were avoided by adjusting the footprint. In some cases, effects were avoided by adjusting the roadway design or were limited by adding a retaining wall versus using a slope which would need more space. Will the project compensate for unavoidable negative effects on wetlands? WSDOT, in partnership with the City of Renton, is developing a mitigation bank called the Springbrook Creek Wetland and Habitat Mitigation Bank. Mitigation banking is one early-action approach identified in the I-405 Corridor Program NEPA/SEPA [Final/Draft] Environmental Impact Statement and the project is part of WSDOT’s watershed approach to wetland mitigation. By consolidating the mitigation at one large site, the opportunity exists to work with a panel of resource agency representatives to create mitigation that specifically contributes aquatic ecosystem functions that are lacking in the local watershed while providing safe, high-quality wildlife habitat away from the dangers of a roadside location. This approach will be used as the wetland mitigation for unavoidable effects to wetlands within the Bank service area. Therefore, the 1.66 acres of permanent effects to wetlands for the Renton Nickel Improvement What is a mitigation bank? A mitigation bank site is a property purchased and developed by a public agency or utility to earn credits to compensate for adverse effects to wetlands due to development activities of other agencies, utilities, or in specific instances, private sector developers. Credits are generated through the restoration, creation, and/or enhancement of wetlands. MEASURES TO AVOID OR MINIMIZE EFFECTS Renton Nickel Improvement Project 56 Wetland Discipline Report Project will be compensated with credits from the Bank. Washington State Executive Order 90-04 mandates that the actions and activities of state agencies achieve a goal of “no net loss” of wetland acreage and function. In recognition of the “Wetlands Executive Order,” WSDOT has adopted the “no-net-loss” goal as agency policy and will meet this requirement for the Renton Nickel Improvement Project at both the project-wide and intra-jurisdictional level. To ensure no-net-loss to wetlands, WSDOT entered into an agreement with Ecology titled the Implementing Agreement between the Washington State Department of Transportation and the Washington State Department of Ecology Concerning Wetlands Protection & Management dated July 1, 1993.14 Wetland mitigation by WSDOT for their projects is currently subject to the 1993 Implementing Agreement. The mitigation ratios that will be used to compensate for effects to wetlands at the Springbrook Creek Wetland and Habitat Mitigation Bank have been designed to meet the “no net loss” guidance mandated under federal and state executive orders and to meet the mitigation, compensation requirements stipulated in the 1993 Implementing Agreement. 14 WSDOT, 1993. Renton Nickel Improvement Project Wetland Discipline Report 57 REFERENCES Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979 Classification of Wetlands and Deepwater Habitats of the United States. Publ. # FWS/OBS-79/31. U.S. Fish and Wildlife Service. Ecology (Washington Department of Ecology) 1997 Washington State Wetlands Identification and Delineation Manual. Publication No. 96-94. Olympia, WA. Washington State Department of Ecology. 1992 The Growth Management Act and the State Environmental Policy Act: A Guide to Interrelationships. Pub No. 92-07. Olympia, Washington. 1991 Shoreline Management Handbook. First Edition. Pub No. 90-45. Olympia, Washington. Environmental Laboratory 1987 Corps of Engineers Wetlands Delineation Manual. Technical Report Y- 87-1. Vicksburg, MS. U.S. Army Engineer Waterways Experiment Station. Federal Register 1994 Changes in Hydric Soils of the United States. Washington, DC. U.S. Government Printing Office. July 13, 1994. 1988 40 CFR Part 230. Guidelines for Specification of Disposal Sites for Dredged or Fill Material. Vol. 45. No. 249, pp. 85336-85357. U.S. Government Printing Office, Washington, D.C. 1986 33 CFR Parts 320 through 33. Regulatory Programs of the Corps of Engineers; Final Rule. Vol. 51. No. 219. pp. 41206-41260. Washington, DC: U.S. Government Printing Office. 1982 Title 33. Navigation and Navigable Waters. Chapter II, Regulatory Programs of the Corps of Engineers. Vol 47, No. 138, pp. 31810. Washington, DC. U.S. Government Printing Office. Hruby, T. 2004 Washington State Wetland Rating System for Western Washington - Revised. Washington State Department of Ecology Publication No. 04- 06-025. Olympia, WA. King County 1990 King County Sensitive Areas Map Folio. Null, W.S., G. Skinner, and W. Leonard 2000 Wetland Functions Characterization Tool for Linear Projects. Olympia, WA: Washington State Department of Transportation Environmental Affairs Office. www.wsdot.wa.gov/environment/biology/docs/bpjtool.pdf. Renton, City of 1992 Renton’s Critical Areas Inventory. Prepared by Jones and Stokes. REFERENCES Renton Nickel Improvement Project 58 Wetland Discipline Report Snyder, D.E., P.S. Gale, and R.F. Pringle 1973 Soil Survey of King County Area, Washington. Washington, DC. U.S. Soil Conservation Service. Tukwila, City of 2004 Draft City of Tukwila Wetland/Watercourse Buffer Map. Dated July 15, 2004. United States Department of Interior, U.S. Fish and Wildlife Service (USFWS) 1997 National List of Vascular Plant Species that Occur in Wetlands. 1996 National Summary. A Draft Revision of Reed, P.B., Jr. 1988. National List of Plant Species That Occur in Wetlands. Northwest (Region 9). Biol. Rpt. 88(26.9). Washington, DC. 1988 National Wetland Inventory, Renton Quadrangle and Mercer Island Quadrangle. 1987 National Wetland Inventory, Des Moines. Washington State Department of Transportation (WSDOT) 2004 Highway Runoff Manual M31-16. Olympia, WA. WSDOT Engineering and Regional Operations Division, Environmental and Engineering Programs, Headquarters Environmental Affairs and Hydraulics. 1993 Implementing Agreement between the Washington State Department of Transportation and the Washington State Department of Ecology Concerning Wetlands Protection & Management dated July 1, 1993. APPENDIX A Wetland Delineation Data Sheets Wetland Rating Forms Wetland Functional Assessment Forms