HomeMy WebLinkAboutBLACK RIVER BASIN WATER QUALITY MANAGEMENT PLAN, Volume 1 BUCK RIVER BASI
WATER QUALITY MANAGEMENT PLAN
... ................. ...
VOLUME 1
CITY OF RENTON
May 1993
Prepared by
R.W. Beck and Associates
and
Herrera Environmental Consultants
in association with
Jones &Stokes Associates
Funded in part by Washington Department of Ecology Centennial Clean Water Fund
Black River Basin Water Quality Management Plan
Volume 1
Prepared for
City of Renton
Department of Public Works
200 Mill Avenue South
Renton, Washington 98055
Washington Department of Ecology
Prepared by
R.W. Beck and Associates
Herrera Environmental Consultants, Inc.
Jones & Stokes Associates
May 1993
CONTENTS
VOLUME 1
Executive Summary...............................................................................ix
1. Black River Basin History ...................................................................1
2. Goals and Objectives of the Plan ...........................................................5
3. Related Planning Efforts .....................................................................9
Kent and Tukwila Planning Efforts.......................................................9
East Side Green River Watershed Plan ..................................................9
History of the Plan................................................................. 10
Preliminary Alternatives .......................................................... 13
Alternative 1 - No Action.................................................. 13
Alternative 2 - Localized Improvements to Springbrook Creek...... 13
Alternative 3 - Flood Flow Diversion Channel/
Springbrook Creek Fisheries Flow Channel .............. 15
Alternative 4 - Pumping of Stormwater from Kent Lagoons
into Green River .............................................. 17
Additional Alternatives to Be Considered ...................................... 19
Alternative 3b................................................................ 19
Alternative 3c................................................................ 19
Preliminary Evaluation of Alternatives ......................................... 19
Recommendations.................................................................. 20
4. Black River Basin Technical Advisory Committee..................................... 21
5. Public Involvement and Education ....................................................... 23
Program Components..................................................................... 23
FactSheet ..............:............................................................ 23
Questionnaire ....................................................................... 23
Citizen Task Force................................................................. 24
PublicMeetings .................................................................... 24
Ongoing Public Involvement and Education Programs .............................. 24
Process for Developing Recommendations..................................... 25
Recommended Program........................................................... 26
FactSheet .................................................................... 26
Resource Signing and Interpretive Trail ................................. 26
Change and Recycle (CAR) Oil Committee............................. 27
Newspaper Articles ......................................................... 28
Stream Team Cleanup ...................................................... 28
Renton River Days Booth.................................................. 28
Lawn Chemical Use ........................................................ 28
6. Historical Data............................................................................... 29
Historical Water Quality Data........................................................... 29
Historical Sediment Quality Data....................................................... 31
Historical Benthic Invertebrate Data.................................................... 32
Summary of Existing Data............................................................... 32
7. Existing Water and Sediment Quality..................................................... 39
iii
Water Quality Monitoring Results ...................................................... 41
Temperature......................................................................... 41
pH .................................................................................... 45
Dissolved Oxygen.................................................................. 45
Turbidity............................................................................. 45
Conductivity ........................................................................ 46
Total Suspended Solids............................................................ 46
Total Phosphorus................................................................... 47
Soluble Reactive Phosphorus ..................................................... 47
OrganicNitrogen................................................................... 48
Ammonia Nitrogen................................................................. 48
Nitrate+Nitrite Nitrogen.......................................................... 48
Copper............................................................................... 49
Lead.................................................................................. 49
Zinc .................................................................................. 49
Cadmium ............................................................................ 49
Hardness............................................................................. 50
Fecal Coliform Bacteria........................................................... 50
Hydraulic and Pollutant Loadings ............................................... 50
Sediment Quality Monitoring Results .................................................. 51
GrainSize ........................................................................... 57
Conventional Parameters.......................................................... 57
Metals................................................................................ 58
Semivolatile Organic Compounds ............................................... 59
Polycyclic Aromatic Hydrocarbons.............................................. 59
Organochlorine Pesticides......................................................... 59
Polychlorinated Biphenyls ........................................................ 60
Herbicides.......:................................................................... 60
Volatile Organic Compounds..................................................... 60
Sediment Disposal Options ....................................................... 60
8. Sources of Basin Problems................................................................. 63
LandUse ................................................................................... 63
Industrial and Commercial Discharge.................................................. 63
Licensed Businesses................................................................ 64
NPDES-Permitted Facilities...................................................... 65
Contaminated Sites................................................................. 66
BPOil Company ............................................................ 66
Renton Junction Landfill ................................................... 67
SterncoSite .................................................................. 67
Hazardous Waste Generators ..................................................... 67
Potential Hazards and Spill Containment .............................................. 67
IndustrialSpills..................................................................... 68
Transportation-Related Spills..................................................... 69
SedimentLoading ......................................................................... 69
Existing Conditions ................................................................ 69
Panther Creek................................................................ 70
Springbrook Springs Tributary............................................ 70
Sediment Loading Estimates............................................... 70
iv
Construction ................................................................. 71
Future Conditions .................................................................. 71
9. Aquatic Resources of Springbrook and Panther Creeks ............................... 73
SpringbrookCreek........................................................................ 73
PantherCreek.............................................................................. 73
Evaluation of Aquatic Resources........................................................ 74
10. Water Quality Summary .................................................................. 75
Springbrook Springs Subbasin........................................................... 75
Panther Creek Subbasin ....................................... . ........................ 76
Rolling Hills Subbasin.................................................................... 77
ValleySubbasin ........................................................................... 77
South Renton Subbasin................................................................... 79
11. Wetlands Assessment...................................................................... 81
Beneficial Impacts on Water Quality and Quantity................................... 81
Mitigation and Enhancement Strategies................................................ 81
12. Fisheries Assessment...................................................................... 85
13. Applicable Regulations and Basin Management....................................... 87
Surface Water Management ............................................................. 87
FloodControl.............................................................................. 88
Ground water Protection and Management............................................ 89
Solid Waste Disposal ..................................................................... 90
Emergency Spill Response............................................................... 91
Onsite Wastewater Disposal ............................................................. 92
Drinking Water Management............................................................ 92
Fisheries and Wildlife Protection ....................................................... 93
AirQuality ................................................................................. 94
14. Capital Improvement Projects ........................................................... 95
15. Problem Definition........................................................................ 97
16. Source Control Alternatives Strategy ..................................................101
Control Alternatives .....................................................................101
Control of Runoff Pollutants from Commercial and Industrial Areas .....101
Control of Runoff Pollutants from Residential Areas........................102
Control of Construction Activities and Resulting Runoff ...................102
Water Quality Monitoring Program ............................................102
Runoff/Water Quality Public Education Program............................103
Drainage Facility Operation and Maintenance Program.....................103
Protection and Acquisition of Wetlands........................................103
Stream and Stream Bank Protection and Rehabilitation .....................103
Emergency Spill Response, Containment, and Cleanup.....................104
Household Hazardous Waste Collection Program............................104
Flood Control and Other Capital Improvement Programs ..................104
City Integrated Pest Management Plan.........................................104
Regulatory Controls...............................................................105
Recommended Implementation strategy ..............................................105
Approach ...........................................................................105
Specific Actions ...................................................................106
17. References .................................................................................117
18. Glossary of Terms ........................................................................121
v
19. Comments on Draft Water Quality Management Plan
and Responses to Comments.....................................................127
FIGURES
1 Black River basin study area .......................................................3
2 Subbasin boundaries .................................................................6
3 Integrated planning approach..................................................... 12
4 ESGRW Plan Alternative 2....................................................... 14
5 ESGRW Plan Alternative 3....................................................... 16
6 Monitoring station locations ...................................................... 40
7 Wetlands............................................................................. 82
8 Implementation strategy..........................................................107
9 Implementation actions...........................................................108
TABLES
1 Washington water quality criteria and water quality statistics for
streams in the Seattle metropolitan area during base flow and
storm flow conditions .......................................................... 30
2 Historical water quality data summary for the Black River basin........... 33
3 Historical sediment quality data summary for the Black River basin....... 35
4 Historical benthic invertebrate data summary for the
Black River basin............................................................... 36
5 Mean water quality results for receiving waters in the
BlackRiver basin............................................................... 42
6 Mean water quality results for storm drains and tributaries in the
southern portion of the Black River basin................................... 43
7 Mean water quality results for storm drains and tributaries in the
northern portion of the Black River basin................................... 44
8 Sediment quality results based on dry weight for Black River basin,
September1991 ................................................................. 52
9 Identified problems in Black River basin study area .......................... 98
vi
APPENDICES
VOLUME 2
Appendix A Water Quality Assessment
VOLUME 3
Appendix B Sediment Loading Estimates
Appendix C East Side Green River Watershed Plan Issues and Criteria
Appendix D Public Involvement and Education
Appendix E Technical Advisory Committee
Appendix F Wetland Inventory
Appendix G Wetland Mitigation Strategies
Appendix H Habitat Inventory
Appendix I Preliminary Water Quality Problem Definition
Appendix J Water Quality Alternatives Analysis
Appendix K Alternative Analysis for East Side Green River Watershed Plan and
Black River Basin Water Quality Management Plan
Appendix L Evaluation of Management Practices
vii
EXECUTIVE SUMMARY
This plan, the Black River Basin Water Quality Management Plan, has been prepared to
identify existing and future water quality problems and to propose a program to address these
identified problems. The study area for the plan covers approximately 5,800 acres and
includes the Rolling Hills, Panther Creek, Springbrook Springs, valley, and south Renton
subbasins.
A parallel and related process, also being prepared under the direction of the city of Renton, is
the development of the East Side Green River Watershed Plan, which is focused on flood
control. Information and recommendations developed in the Black River basin plan will
provide useful input to the East Side Green River Watershed Plan. Another related water
quality planning effort is occurring in the city of Kent, which has recently prepared its five-
year water quality program for the years 1992-1996.
The Black River has undergone major changes over the past century. Significant drainage
modifications have substantially reduced the size of the Black River basin and confined the
basin to a 24-square-mile area on the east side of the Green River south of Renton. The
principal stream within the Black River basin is Springbrook Creek, which arises south of the
project study area and receives flow from streams descending off the plateau east of the Green
River valley. Rapid urbanization of the Renton-Kent area has resulted in problems that are
typical of urban areas in the Puget Sound region.
Water and sediment quality data collected during this study, as well as historical water and
sediment quality data, show that streams in the study area have poor water quality. These
data, together with field observations made during this study, have enabled the identification of
specific problems and probable sources of these problems in the study area.
Significant problems in the study area include the following:
■ High levels of metals, fecal coliform bacteria, nutrients, and turbidity in
storm flows in most streams
■ High levels of fecal coliform bacteria, elevated temperatures, and low
levels of dissolved oxygen in base flows in most streams
■ Stream bank erosion and barriers to fish passage in tributaries to
Springbrook Creek.
Other specific problems have been identified. The problems listed here are typical of urban
streams systems. However, comparison of data obtained during this study with data from
other areas of Puget Sound shows that Springbrook Creek has poorer water quality than most
Puget Sound streams, indicating an urgent need to address water quality problems within the
study area.
ix
To improve water quality in the Black River basin, this plan recommends that the city
implement a strategy consisting of a set of specific actions. These actions include the
following:
■ Public involvement and education
■ Increased coordination within the city and between the city and other
jurisdictions
■ Efforts to pinpoint sources of problems
■ Improvements in city inspection, enforcement, and maintenance of storm
drainage systems and related facilities
■ Specific capital improvement projects to correct known problems
■ Ongoing monitoring of water and sediment quality
■ Periodic assessment of program progress.
Many of the recommendations of this plan will be incorporated into the Renton comprehensive
storm and surface water management plan, which is currently being developed.
This document is published in three volumes. The body of the Black River Basin Water
Quality Management Plan is contained in Volume 1. The complete water quality assessment is
provided in Volume 2, and other supporting data and project records are collected in
Volume 3.
x
1. BLACK RIVER BASIN HISTORY
In the mid-nineteenth century, when eastern settlers first arrived in the Renton vicinity, the
rivers and streams of the Lake Washington-Elliott Bay drainage created a network dramatically
different from today's pattern. In the 1800s, the Black River drained Lake Washington
through an outlet located where the Renton Airport sits today. The Cedar River joined the
Black River a short distance south of the lake. Also in the nineteenth century, the White
River, draining the north side of Mount Rainier, flowed past Enumclaw, turned north just
south of the present location of Auburn, and, after receiving the waters of the Green River,
continued north to join the combined Black and Cedar rivers and flow into Elliott Bay as the
Duwamish River. At the turn of the century, then, all four rivers, the White, Green, Black,
and Cedar, contributed to the Duwamish River.
In 1906, a particularly large flood diverted the White River into the Stuck/Puyallup drainage.
The U.S. Army Corps of Engineers shortly thereafter made the drainage change permanent by
constructing a diversion dam and enlarging the Stuck and Puyallup river channels, and today
the White River flows via the Puyallup River into Tacoma's Commencement Bay. After this
drainage change, the Green River contributed most of the flow, and later its name, to the river
segment that runs along the west side of Auburn and Kent.
In 1916, the Lake Washington ship canal was completed, and operations at the new canal
lowered the lake by about 9 feet. This change brought the lake surface below the level of the
outlet at Renton, and lake water ceased to flow into the Black River. Since that time the lake
has discharged west through the ship canal and locks. Sometime in the late 1920s or early
1930s, the flow in the Black River was reduced further when the lower Cedar River was
channelized through Renton and diverted into Lake Washington.
At the turn of the twentieth century, two county drainage districts were organized: King
County Drainage District No. 1, located between Kent and the Black River, and Drainage
District No. 2, located northwest of Kent. Together with the U.S. Soil Conservation Service
and local jurisdictions, the two districts have modified drainage in the Green River valley in an
attempt to provide flood and drainage control. Streams flowing off the west side of the Soos
Creek plateau have been channelized and directed northward on the valley floor. Construction
of flood control dikes along the east side of the Green River has effectively isolated surface
water flow in the east side of the valley from the river.
In 1966, the East Side Green River Watershed project was conceived. Sponsored by local
jurisdictions in the area, this ongoing project is intended to further control flooding in the
Green River valley east of the river and north of Auburn. Completed components of the
project include the Black River pump station and forebay (a storage pond) and the P-1 channel.
The P-1 channel is the channelized lower portion of Springbrook Creek, a major drainage
channel on the valley floor east of the Green River.
As a result of all of the drainage changes that have occurred in this century, surface waters
within the entire east side of the Green River valley north of Auburn now flow to the Black
River pump station where they are pumped into the Black River channel.
1
The transformation of the Black River basin is now virtually complete. The Black River basin,
which at one time included areas as geographically separate as southwest Everett, Issaquah,
and the Cascade crest south of Snoqualmie Pass, today is confined to a rapidly developing 24-
square mile area south of downtown Renton (Figure 1). The urbanizing character of the basin
carries with it particular problems and opportunities that are the subject of this plan.
2
N
oy
5
°� Lake
Washington
Cedar River
TUKWILA
STUDY
AREA
SEA-TAC XXXX
a
c
DES
MOINES
167 KENT
Puget 18
5ounii
5
AUBURN
FEDERAL WAY 18
Otte
0 1 2 3
SCALE IN MILES
Black River Basin Water Quality Management Plan
Figure 1. Black River basin study area
3
2. GOALS AND OBJECTIVES OF THE PLAN
In 1987 the Puget Sound Water Quality Management Plan directed the 12 counties bordering
Puget Sound to develop and carry out action plans to control nonpoint source pollution within
individual watersheds. In response to this direction, the Green-Duwamish Watershed
Management Committee was formed in 1988 to develop a comprehensive nonpoint water
quality action plan for the Green-Duwamish watershed. The completed action plan
recommended development of the present document, the Black River Basin Water Quality
Management Plan.
The intent of the Black River plan is to identify existing and future surface water quality
problems in the Black River basin and develop solutions to these problems. The study area for
the plan covers approximately 5,800 acres and includes the Rolling Hills, Panther Creek,
Springbrook Springs, valley, and south Renton subbasins (Figure 2).
The goals and objectives of the Black River Basin Water Quality Management Plan, as defined
by the citizen task force, are listed below, ranked by the task force in order of importance:
1. Control and improve surface water quality within the Black River basin
2. Characterize and identify measures to maintain and enhance existing and
constructed wetlands for improved surface water quality, wildlife
habitat, and flood control
3. Conduct an appropriate public involvement and education program
4. Identify mechanisms to reduce contamination and deposition of stream
sediments
5. Characterize and identify measures to improve surface water quality
impacts on fish access and habitat
6. Develop a plan that recognizes the need for proper disposal of household
hazardous wastes
7. Identify appropriate point and nonpoint source control strategies and
regulatory options for surface water management within the Black River
basin
8. Assure coordination of this plan with the programs of the other
jurisdictions within the Black River basin
9. Implement a long-term monitoring program
10. Recognize upstream water quality influences on the Black River basin
(i.e., Kent)
5
N
� RE TON
Uru�`Pads
PP
South Renton Subbasin 1—
Pumping
Station '�° f-
t Basin/Study Area
�,� ,r•• e Boundary
Rolling \
sw 16th St. Hills
Drain
. Rolling Hills
................. \I
Subbasin
CAannel
�`00o I8
i
181 a Panther
I Creek
Wetland
Valley Subbasin
sw 3an st.
Sw 43rd St.
Panther Creek Subbasin
I /, 167 8 'a
e e
S.792nd St. i
e \.
e ` `
LEGEND
------ Stream/Drainage Channel Springbrook
Springs
1
............•• Storm Drain Pipe ¢ Subbasin
Subbasin Boundary 1 /
0 1000 2000 3000 ,
\ ` 1
SCALE IN FEET
Black River Basin Water Quality Management Plan
Figure 2. Subbasin boundaries 6
11. Develop incentive programs
12. Develop a plan that recognizes the need for enforcement of water quality
violations.
A parallel and related process is the development of the East Side Green River Watershed
(ESGRW) Plan, also being prepared under the direction of the city of Renton. The ESGRW
Plan focuses on flood control. Information and recommendations developed in the Black River
basin plan will provide useful input to the ESGRW Plan. Section 3 of this document addresses
this linkage.
Lastly, recommendations developed here will be incorporated into the comprehensive storm
and surface water management plan now being formulated by the city of Renton. The timing
of implementation of the capital improvement projects recommended here will depend on
funding and the priority of individual projects.
7
3. RELATED PLANNING EFFORTS
KENT AND TUKWILA PLANNING EFFORTS
The city of Kent recently completed its five-year (1992-1996) water quality program. In
preparing this program, the city investigated current water quality in its streams and other
water bodies. The planning effort defined objectives for the 5-year period and proposed the
following eight program elements:
■ Monitoring
■ Code enforcement
■ Reduction in pollution from public facilities
■ Community information and involvement
■ Mill Creek improvement plan
■ Regional stormwater treatment projects
■ Natural resource protection
■ Program administration.
Kent's efforts to improve water quality within its boundaries will affect water quality in the
portion of the Black River basin within Renton because most of Kent's surface waters flow
into Springbrook Creek. Close coordination between Kent and Renton will be crucial to
providing focused and cost-effective actions to improve water quality within the two
jurisdictions.
In December 1992 the city of Tukwila completed its Southeast Central Business District
Drainage Study, covering the area bounded on the west by the Green River, on the east by the
Burlington Northern Railroad tracks, on the north by Strander Boulevard, and on the south by
South 180th Street. Approximately 109 acres of the 147.2-acre study area drains into
Springbrook Creek. The study contains recommendations for improvements to drainage
facilities in the study area and for drainage facilities to be required in new developments. The
city of Tukwila also completed the Nelson Place/Longacres Way Drainage Report discussing
recommendations for drainage improvements in that vicinity.
EAST SIDE GREEN RIVER WATERSHED PLAN
The East Side Green River Watershed (ESGRW) Plan is a concurrent planning effort being
conducted by the city of Renton with the primary goal of developing a comprehensive storm
and surface water management plan that minimizes impacts to environmental resources and, if
possible, enhances these resources while providing flood protection in the Renton valley. The
Renton valley is subject to severe recurrent flooding. A comprehensive examination of this
problem is essential because of the sensitive nature of the area's environmental resources.
9
History of the Plan
A detailed discussion of the project history may be found in the ESGRW Plan Project
Summary Document (R. W. Beck and Associates 1991). The current ESGRW planning effort
reflects a reexamination of past ESGRW studies primarily developed by the Soil Conservation
Service. These original studies began in the 1960s when the cities of Auburn, Kent, Renton,
and Tukwila, along with King County, the Green River Flood Control Zone District, the King
Conservation District, and the King County Drainage District, passed a resolution requesting
flood protection from the federal government under the Watershed Protection and Flood
Prevention Act (Public Law 566). This program is administered by the Soil Conservation
Service.
The Soil Conservation Service developed a detailed work plan for the watershed, entitled the
ESGRW Plan, which was approved and funded by Congress. This work plan led to the
construction of the Black River pump station, the first component of the recommended flood
control system. In 1972, the National Environmental Policy Act (NEPA) was enacted, and an
environmental impact statement was prepared for the ESGRW Plan.
The project was temporarily put on hold in 1982 when local sponsors withdrew from the plan
because of the high cost of the project and diminishing local support. In 1983 however, the
city of Renton assumed lead agency status from King County to reactivate the project. The
city, with assistance from the Soil Conservation Service, coordinated the construction of the
Black River pump station forebay, the P-1 channel from the pump station to SW Grady Way,
the Grady Way box culvert, the Interstate-405 (I-405) box culvert, the Oakesdale Avenue SW
retaining walls, and the SW 16th Street bridge.
In 1988, the city conducted a process to formally adopt the Soil Conservation Service NEPA
environmental impact statement to extend construction of the P-1 channel to SW 43d Street
and the P-9 channel/Panther Creek wetland project. The adoption process generated concerns
and comments from various regulatory agencies, environmental groups, and citizens who
questioned the completeness and adequacy of the original Soil Conservation Service NEPA
environmental impact statement in addressing project-specific environmental impacts and
mitigation measures. The city then suspended the adoption process and conducted an adequacy
determination study of the Soil Conservation Service final environmental impact statement for
the ESGRW Plan. This study identified the specific deficiencies in the original Soil
Conservation Service NEPA environmental impact statement with respect to wetland impacts
(in accordance with current wetland regulations) and impacts on streams, wildlife habitat,
fisheries resources, and water quality. In addition, the Soil Conservation Service hydrologic
and hydraulic watershed models were considered out of date due to changes in the drainage
system, changes in the philosophy of stormwater control (including increased importance of
environmental issues), and advances in hydraulic and hydrologic modeling techniques and
computer capabilities.
The determination that the original NEPA environmental impact statement was inadequate led
to the current ESGRW planning effort, which includes several elements to provide a
comprehensive examination of the watershed:
10
■ Development of new hydrologic and hydraulic models for the watershed
that consider the changed conditions in the watershed and new modeling
technology
■ Aquatic resources evaluation
■ Water quality evaluation and assessment
■ Wetland inventory and assessment
■ Flood control alternatives analysis
■ Financial and policy analysis
■ Agency coordination
■ Public meetings.
As previously noted, many of the environmental elements of the ESGRW Plan are being
conducted under the Black River basin plan. Figure 3 illustrates the relation between the
ESGRW Plan and the Black River basin plan.
Many elements of the current ESGRW Plan have been completed. The following reports have
been prepared as a part of the plan.
■ ESGRW Plan Current Condition Document (R.W. Beck and Associates
1991), which describes the current flooding and environmental resource
problems in the Renton valley
■ ESGRW Plan Project Summary Document (R.W. Beck and Associates
1991), which describes the ESGRW planning project, its history, and the
preliminary flood control solutions under consideration by the city
■ ESGRW Hydrologic Analysis (Northwest Hydraulic Consultants 1991),
which describes the hydrologic modeling of the ESGRW using the
Hydrologic Simulation Program - Fortran (HSPF)
■ ESGRW Plan Hydraulic Analysis Report - Existing Drainage System
(R.W. Beck and Associates 1992), which describes the hydraulic
modeling of Springbrook Creek using the FEQ (full equations) computer
model to determine the floodplain elevations of the existing drainage
system under current and future land use conditions.
With these studies completed, and considering the environmental information gathered as a
part of the Black River basin plan, the city conducted a preliminary screening of alternative
flood control solutions (see Volume 3, Appendices C and K). Thirteen flood control solutions
were identified, and the group was narrowed to four alternative flood control solutions,
described in the following section.
11
Black River Basin Water
Quality Management Plan
Recommended
Water Quality Assessment ANALYSIS -- o Solutions to Improve
Wetlands Inventory Water Quality in Basin
Source Control
Environmental Considerations
for Flood Control
Public Involvement
Water Quality / Wetlands /
N Aquatic Resource Information
East Side Green River
Watershed Plan
Recommended Flood
Control Solution
Hydrology Sensitive to
Hydraulics ANALYSIS Environmental
Fisheries Considerations
Policies / Financial
Figure 3. Integrated planning approach Black River Basin Water Quality Management Plan
Preliminary Alternatives
The ESGRW Plan alternative flood control solutions under consideration by the city of Renton
are described below. These alternatives are preliminary and may be refined to include
additional flood control solutions for specific problems. Appendix K (Volume 3) describes the
evaluation process used to select these preliminary alternatives. Detailed elements within each
alternative could change based upon recent evidence that the hydrologic modeling results
developed in the ESGRW hydrologic analysis (Northwest Hydraulic Consultants 1991) may
have underestimated actual flood flows in Springbrook Creek. Hydrologic modeling that
includes precipitation data from 1990 and 1991 is expected to indicate higher flows. A
discussion of the potential impacts on water quality of the four preliminary flood control
alternatives is included in Volume 3, Appendix J. Concerns regarding fisheries and other
habitat issues will be addressed in the final ESGRW Plan.
Alternative I - No Action
The no-action alternative will address what happens to the existing drainage system if
development in the watershed continues and no flood control solutions are implemented.
Alternative 2 - Localized Improvements to Springbrook Creek
This alternative includes localized improvements to Springbrook Creek combined with other
drainage improvements to eliminate existing flooding problems in the valley area. These
improvements are the following (Figure 4):
1. Improve the capacity of existing Springbrook Creek culvert crossings at
SW 27th Street, SW 34th Street, and Oakesdale Avenue by installing
additional culverts alongside the existing culverts or by replacing the
culverts with bridges.
2. Improve the capacity of the existing storm drainage system along SW
43d Street between Lind Avenue and the intersection of SW 41st Street
with Oakesdale Avenue. Alternatives include pipe replacement or
construction of a new storm drain system. The new system could be
aligned parallel to the existing pipe or along Lind Avenue and SW 41st
Street.
3. Improve the capacity of Springbrook Creek by widening approximately
300 feet of Springbrook Creek between the existing railroad tracks and
SW 41st Street.
4. Include measures to improve valley area wetlands. This may be
accomplished by modifying the existing hydraulic connections to selected
valley area wetlands and/or construction of a fish passage control gate on
Springbrook Creek north of SW 23d Street in order to improve wetland
hydration during the dry summer months.
13
N
RENTON
PP
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—Rolling
_ SWtuhSt. Hills
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ym g
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Divert Panther Creek
%• into Wetland
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Improvement (/
• SW 41 ct St `
SW 43rd St.
o 181 \ '
r �
LEGEND S.192nd St.
------ Stream/Drainage Channel
I.•-----•-•-•-•• Storm Drain Pipe
o Culvert Replacement/
Improvement
o Plug Existing Culvert l
E•••••••• Channel Improvement �k
1
New Storm Drain � 1
0 1000 2000 3000
SCALE IN FEET ` 1
Black River Basin Water Quality Management Plan
Figure 4. ESGRW Plan Alternative 2
14
5. Make improvements to the Panther Creek wetland and reestablish
Panther Creek the (P-9 channel), in order to reestablish a natural stream
channel between Springbrook Creek and Panther Creek, with a portion
of this channel designed for salmon spawning habitat. This would also
help to eliminate flooding problems along East Valley Highway where
dispersed Panther Creek flows enter the existing undersized drainage
system. The Panther Creek wetland and creek improvements include the
following:
a. Install a new culvert crossing under state route (SR)-167 for the
reestablished Panther Creek, to carry outflows from the Panther
Creek wetland to the restored stream channel, which would
convey flow west and discharge into Springbrook Creek.
b. Reduce the number of outlets from the Panther Creek wetland to
two by plugging all other SR-167 culvert crossings. The two
remaining crossings include the new crossing discussed under
item 5a above, and the existing 3x4-foot box culvert that carries
runoff underneath SR-167 from the Rolling Hills drain. In
addition, install a control structure on this box culvert to divert
low flows to the new culvert crossing and the reestablished
Panther Creek channel, in order to maintain adequate base flows
in the channel during the spawning season.
C. Deepen and widen the existing ditch along the P-9 channel
alignment to allow construction of the reestablished Panther
Creek between the proposed new Panther Creek wetland outlet
and Springbrook Creek.
d. Design a section of the reestablished Panther Creek between Lind
Avenue and East Valley Highway for salmon spawning.
6. To improve water quality, include features such as increased planting of
trees along the stream channel.
Alternative 3 - Flood Flow Diversion Channel/Springbrook Creek Fisheries Flow Channel
This alternative reflects the original Soil Conservation Service P-1 channel and Panther Creek
wetland/P-9 channel project, with some modifications. The modifications are based on the
preliminary results of the hydrologic/hydraulic modeling and are designed to be compatible
with present city drainage planning. For example, the city plans to maintain the existing
Springbrook Creek as a fisheries flow channel (up to 2-year frequency flow). Maintaining
Springbrook Creek as a fisheries flow channel would also be necessary to assure adequate
hydration of wetlands and to minimize impacts on fisheries, water quality, and wildlife. The
improvements are the following (Figure 5):
15
N
RENTON
/ PP
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Pumping
Station ,\�.= r• ' Basin/Study Area
\�� sW GrodY WaY •�,..1 ; Boundary
•
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II � II g
� P-9Channel New Control
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P 00000 .
a
sw 271 New Dike St. ^✓
d�� 0 New Open Water/
C =o� Marsh Habitat
�jc00 """"' Panther
Creek
181 Wetland
� N W
W 1
• a I SW 301 St. `
J Divert Panther Creek
• . into Wetland
•
•
i
• SW 41 at St
•
• SW 43rU111-St. \\
\
Diversion
Structure
U i / 167 \� '
LEGEND s.lezna s,.
------ Stream/Drainage Channel
.............•• Storm Drain Pipe j ` ��•.�.
o Culvert Replacement/ \\�
Improvement
o Plug Existing Culvert
q I�•••••••• Channel Improvement
New Storm Drain
0 1000 2000 3000 `
\ 1
SCALE IN FEET
Black River Basin Water Quality Management Plan
Figure 5. ESGRW Plan Alternative 3
16
I
1. Divert high flows from Springbrook Creek immediately upstream of the
SW 43d Street culvert crossing into a new P-1 flood flow diversion
channel. The P-1 flood flow diversion channel would then reconnect to
Springbrook Creek at the confluence of Springbrook Creek and the
proposed reestablished Panther Creek (P-9 channel) alignment. The P-1
flood flow diversion channel bottom width would be approximately 70
feet, with 3-to-1 side slopes. A diversion structure to divert high flows
into the P-1 channel would consist of a long weir designed to maintain a
fisheries flow in Springbrook Creek of not less than approximately the 2-
year frequency flow. The channel would be deep and the channel
bottom may provide habitat for aquatic plants and animals (i.e., it may
become a created wetland). Because of the depth of the channel, the
project may require provisions to prevent dewatering of adjacent
wetlands.
2. Make enhancements to the Panther Creek wetland and reestablish
Panther Creek (the P-9 channel) as discussed under Alternative 2.
3. Improve the capacity of the existing storm drainage system along SW
43d Street between Lind Avenue and the intersection of SW 41st Street
with Oakesdale Avenue as discussed under Alternative 2.
4. Make channel improvements between SW 16th Street and SW Grady
Way, to include a flood flow diversion from Springbrook Creek through
the existing I-405 box culvert. High Springbrook Creek flows would be
diverted to a new channel section immediately downstream of SW 16th
Street. The diversion would then pass through the existing I-405 box
culvert and reconnect to Springbrook Creek upstream of SW Grady
Way. This would maintain fisheries flows through the existing
Springbrook Creek riparian corridor under I-405 and would maintain
maximum biofiltration and habitat values. The diversion of flood flows
through the I-405 box culvert would alleviate a current erosion problem.
5. To improve water quality, include features such as increased planting of
trees along the stream channel.
Alternative 4- Pumping of Stormwater from Kent Lagoons into Green River
This alternative includes a pump diversion from the old Kent sewage lagoons site to the Green
River. The city of Kent is planning to use the old lagoon site as a large regional detention
pond and wetland/habitat enhancement project (Kent 1991). One of the primary goals of this
project is to reduce peak flow rates in the lower reaches of Mill Creek. This alternative would
reduce downstream flows not only in Kent but also in the city of Renton.
The Kent lagoons project would divert high Mill Creek flows to the lagoon site, which has
storage capacity of approximately 330 acre-feet. The proposed Kent lagoons project currently
consists of a 4-foot-diameter gravity outfall (gravity drainage) to the Green River with a flap
17
gate. Discharges from the gravity outfall would be limited in accordance with requirements of
the Green River Management Agreement and the Green River Pump Operations and
Procedures Plan, which require that new Green River gravity or pump outfalls stop
discharging when flow in the Green River reaches 9,000 cubic feet per second (cfs) at the
Auburn gauge.
When the Green River flows reach 9,000 cfs, the proposed Kent lagoons would provide 25-
year flood storage capacity. Once the storage capacity of the lagoons is reached, an overflow
channel would return flows to Mill Creek and on into Springbrook Creek through Renton to
the Black River pump station, where flows would then be pumped into the Green River, as
allowed by the Green River Management Agreement. The Green River Management
Agreement, which was entered into by King County and the cities of Auburn, Kent, Renton,
and Tukwila in 1985, sets forth pumping limitations for all existing and future pump stations
discharging to the Green River.
Preliminary investigations performed as a part of the ESGRW Plan indicate that the
performance of the Kent lagoons project in reducing Mill Creek flows could be substantially
improved if pumping from the lagoons is allowed up to Green River flows of 12,000 cfs as
measured at the Auburn gauge. The primary difference between Alternative 4 and the currently
planned Kent lagoons project is that the former would allow pumping from the Kent lagoons
site to the Green River during high Green River flows of 12,000 cfs rather than 9,000 cfs.
Allowing pumped discharges from the lagoons to the Green River during Green River flows of
12,000 cfs would require a modification to the Pump Operations and Procedures Plan and the
Green River Management Agreement, as well as approval by the Green River basin technical
advisory committee. The Pump Operations and Procedures Plan is scheduled to be updated in
early 1993 as part of the Green River Basin Program. The Green River Basin Program, which
was initiated by King County and the valley cities in 1978, addresses surface water resource
problems and manages major flood control projects in the basin.
To prevent an increase in the cumulative pumped flows into the Green River, a modification of
the Green River Management Agreement would likely consist of shifting an allotment of the
allowable pump discharge from the Black River pump station to the Kent lagoons or using
excess capacity in the Green River, if excess capacity is available.
Again, preliminary estimates show that this alternative could be extremely effective in
reducing downstream flow rates in both the lower sections of Mill Creek in Kent and
Springbrook Creek in Renton. In addition, the reduced flows in Springbrook Creek would
eliminate the need for major channel or conveyance system construction and eliminate
associated impacts to wetlands and the creek. The improvements are the following:
1. Make enhancements to the Panther Creek wetland and reestablish
Panther Creek (the P-9 channel), as discussed under Alternative 2.
2. Improve the capacity of the existing storm drainage system along SW
43d Street between Lind Avenue and the intersection of SW 41 st Street
with Oakesdale Avenue, as discussed under Alternative 2.
18
3. To improve water quality, include features such as increased planting of
trees along the stream channel.
Additional Alternatives to Be Considered
The city is presently considering two additional flood control alternatives that may be included
in subsequent evaluations. Both alternatives are variations to Alternative 3, discussed above,
and are referred to as Alternatives 3b and 3c. A brief description of these alternatives is
provided below.
Alternative 3b
This alternative is similar to Alternative 3, except that the flood flow channel would be
constructed at a higher elevation to prevent dewatering of adjacent wetlands. The ground
surface elevations of most of the large remaining wetlands in the valley are at the original
valley floor elevation of 10 to 11 feet, surrounded by fill areas at elevations of 16 to 20 feet.
The bottom elevation of the flood flow channel would be at or above the original ground
elevation of the valley floor (i.e., equal to or above ±11 feet elevation) to preclude the
possibility of dewatering wetlands. All other aspects of Alternative 3 would be as described
earlier.
o Alternative 3c
This alternative is similar to Alternative 3, except that the flood flow channel would be
designed to convey both the low flow and flood flow of Springbrook Creek upstream of SW
43d Street, rather than just flood flows. In order to accomplish these objectives, this
alternative would require the realignment of Springbrook Creek from SW 43d Street to the
confluence of Springbrook Creek and the reestablished Panther Creek. The existing
Springbrook Creek channel between SW 43d Street and the reestablished Panther Creek would
serve only to convey local flows from the contributing valley area. This section of the existing
Springbrook Creek could then be modified to act as a water quality feature, improving the
quality of runoff from the valley area.
Preliminary Evaluation of Alternatives
The city and consulting team conducted a preliminary evaluation of the ESGRW Plan flood
control Alternatives 1 through 4 (excluding 3b and 3c) using the following evaluation criteria:
■ Effectiveness in solving flooding
■ Wetland considerations
■ Water quality considerations
■ Fisheries considerations
■ Cost/benefit
■ Aesthetics/human environment
19
i
■ Operations and maintenance
■ Financing
■ Feasibility of implementation
■ Interjurisdictional requirements
■ Transportation considerations.
The detailed evaluation of flood control alternatives (which may involve criteria such as
wildlife considerations) and selection of the preferred alternative will be presented in the
ESGRW Plan, which is scheduled for completion in mid-1993.
Recommendations
As previously discussed, the preliminary ESGRW alternative flood control solutions were
developed and evaluated based upon hydrologic information that may underestimate actual
Springbrook Creek flow rates. The original HSPF hydrologic analysis did not include the
recent severe flood events of 1990 and 1991 (the January 1991 event was the largest flood in
the 30-year record of precipitation). As a result, the preliminary flood control solutions
developed to date may be inadequate to solve valley flooding problems. It is recommended
that the city update the hydrologic model, taking into consideration these recent floods, and
reconsider the adequacy of the flood control alternatives. The detailed evaluation of
alternatives could then be conducted and a preferred alternative could be selected.
It is also recommended that the cities of Renton and Kent continue discussions regarding
implementation of the Kent lagoons project (Alternative 4) and other regional flood control and
water quality facilities.
20
4. BLACK RIVER BASIN TECIINICAL ADVISORY COMMITTEE
A technical advisory committee was formed by the city of Renton to assist in development of
the Black River basin plan. The following agencies, environmental groups, and municipalities
were invited to attend each of the committee meetings:
■ Washington Department of Ecology
■ Washington Department of Fisheries
■ Washington Department of Wildlife
■ Washington Department of Transportation
■ U.S. Environmental Protection Agency
■ U.S. Soil Conservation Service
■ U.S. Army Corps of Engineers (Wetlands Regulatory Group)
■ Municipality of Metropolitan Seattle (Water Quality Planning)
■ Muckleshoot Tribe
■ Seattle Audubon Society
■ Soos Creek Water and Sewer District
■ City of Kent
■ City of Tukwila
■ King County Surface Water Management Division
■ King County Drainage District No. 1.
Two meetings were held, in late 1991 and early 1992, and a third meeting was held in late
1992 to present the draft report and receive comments. Not all of the groups listed above have
been able to attend the meetings. Technical advisory committee meeting records are provided
in Volume 3, Appendix E.
The first meeting included an introduction to the Black River basin planning process. Methods
of conducting the Black River basin plan and ESGRW Plan study tasks were presented. The
ESGRW Plan, a concurrent flood control planning effort by the city of Renton, is discussed in
greater detail in Chapter 3 of this report.
The second meeting included a discussion of the study tasks that had been completed for both
planning projects. Results were presented on the Black River basin wetlands and aquatic
resource inventories, industrial discharges in the basin, sediment sampling findings, and a
public questionnaire mailer. Work products for the ESGRW Plan were also presented,
including studies on basin hydrology and hydraulics, as well as preliminary flood control
alternatives.
21
5. PUBLIC INVOLVEMENT AND EDUCATION
At the outset of this project, all participants recognized the importance of an active public
involvement and education program. A public involvement program has been an important
component of efforts elsewhere in the Puget Sound region to control nonpoint sources of
pollution. The Black River basin program was developed in conjunction with the citizen task
force and the technical advisory committee. Details of the public involvement and education
program are provided in Volume 3, Appendix D. The program is intended to achieve the
following:
■ Increase public awareness of the water resources present in the basin
■ Inform and educate the public and local businesses regarding activities
that can lead to water quality degradation
■ Reduce the introduction of pollutants into the drainage system through
voluntary action of the public and businesses
■ Evaluate and recommend ongoing public involvement and education
programs that the city could implement following completion of the
Black River Basin Water Quality Management Plan.
PROGRAM COMPONENTS
The program included mailing of a fact sheet (flyer) and a questionnaire, formation of a citizen
task force, and public meetings. These program components are discussed in the following
paragraphs.
Fact Sheet
A flyer providing information about water quality and control of pollutant sources was mailed
to approximately 1,500 residents and businesses in the Renton portion of the Black River
basin. The flyer also informed the public about the basin plan and encouraged residents to
attend a public meeting about the project.
Questionnaire
A questionnaire was mailed to approximately 1,500 residents and businesses in the basin,
requesting information on interests or concerns relating to the Black River basin. In addition,
the questionnaire invited individuals to join the citizen task force. Over 100 responses to the
questionnaire were received, with 35 people showing interest in joining the task force. The
primary issues of concern, as rated by respondents to the questionnaire, are listed here in order
of priority:
23
■ Preservation of water quality
■ Prevention of toxic and hazardous waste spills from industrial sites and
traffic accidents
■ Impacts of new development on water quality
■ Public education about how individual actions affect water quality
■ Protection and preservation of wetlands
■ Control of household hazardous waste.
Citizen Task Force
The citizen task force was formed to participate in the planning effort. The primary emphases
of the task force are to identify, evaluate, and select public involvement and education
programs that the city, interested citizens, and businesses could implement following
completion of the Black River basin plan. Five meetings have been held, in late 1991 and
throughout 1992. The first meeting included an introduction to the project. At the second and
third meetings, results of the study findings were presented, and public involvement and
education programs were identified and evaluated. The fourth meeting was held to present the
draft plan, with the study findings, and receive comment. The fifth meeting, in late 1992,
focused on recommended source control alternatives and recommended public involvement
programs. Citizen task force meeting records are included in Volume 3, Appendix D. The
citizen task force's involvement in developing the preferred public involvement and education
program is discussed in the following section.
Public Meetings
A public meeting was conducted on November 19, 1991 to present and explain the project.
Only one citizen attended the meeting. A second meeting will be conducted following public
circulation of the draft plan, to present the study findings and receive public comment.
ONGOING PUBLIC INVOLVEMENT AND EDUCATION PROGRAMS
As discussed above, one of the purposes of the initial public involvement and education
program is to recommend a series of ongoing programs to be implemented after completion of
this study. To ensure local support, the citizen task force was used to select the most suitable
programs within the basin. Although the emphasis of this study is the Black River basin, both
city staff and the citizen task force support the extension of these programs on a citywide
basis.
24
Process for Developing Recommendations
Of the five citizen task force meetings, two specific meetings were set aside to discuss ongoing
public involvement and education programs. During the first meeting, there was a general
discussion about public involvement and education programs. To increase awareness of the
variety of programs available, a summary of 28 sample public education programs taken from
the 47 Success Stories from Puget Sound (prepared by the Washington Department of Ecology
in 1991) was provided to each task force member. In addition, select programs from the
Puget Sound Book on Maintaining the Health of the Puget Sound Region (prepared by the
Municipality of Metropolitan Seattle in 1991) were provided to all members. The task force
reviewed relevant examples of programs that might be effective in the Black River basin.
Following this general discussion, the committee was divided into two smaller groups for
further discussion about programs specific to the Black River basin. Out of the small
discussion groups, eight additional public education and involvement programs were identified.
Each member of the task force voted for three preferred programs, and the group of 36
possible programs was narrowed to the following 13 programs:
■ Interpretive trail - 8 votes
■ Lawn chemical use (alternatives) - 6 votes
■ Salmon Days - 5 votes
■ Renton River Days - 5 votes
■ Fact sheet - 3 votes
■ Hazard-free community - 2 votes
■ CAR (change and recycle) oil committee - 2 votes
■ Public information television channel - 2 votes
■ Rainy Days festival - 1 vote
■ Water resources poster - 1 vote
■ Waste management for auto shops - 1 vote
■ Stream team program - 1 vote
■ Calendar of events - 1 vote.
The objective of the second meeting was to review and elaborate on the 13 public education
programs identified during the first meeting, and then to vote a second time to select the most
effective programs for reducing water quality degradation in the basin.
As a result of discussions during the second meeting, the task force identified several new
programs and revised the emphasis given to some of the previous 13 programs, including the
following:
■ Use of resource identification signs (such as "Entering the Black River
Basin," "Springbrook Creek," "Panther Creek," and "Panther Creek
Wetland") as a part of the interpretive trail to increase public awareness
of important environmental resources
■ Use of a stream team program in which local volunteers would organize
litter collection
25
■ A speaker bureau of volunteers available to speak to interested groups
(such as churches and citizen groups) about water quality.
Following these discussions, the task force members voted for the programs that they felt
would be most effective in eliminating water quality problems, with the following results:
■ Resource signing and interpretive trail - 7 votes
■ Fact sheet with various focuses - 5 votes
■ CAR (change and recycle) oil committee - 4 votes
■ Renton River Days booth - 3 votes
■ Stream team cleanup - 3 votes
■ Newspaper article - 3 votes
■ Hazard-free community - 2 votes
■ Alternatives to lawn chemical use - 2 votes.
Recommended Program
The recommended ongoing public involvement and education program consists of both
informational and action elements. These elements are described below.
Fact Sheet
Fact sheets could be sent out quarterly or twice a year, with each mailing directed to a
different audience or a different focus. For example, a specific message could be sent to the
top 50 priority industries on ways to safeguard against accidental spills of pollutants. Another
example would be a fact sheet sent to residents on proper lawn care and the use of chemicals.
Still another fact sheet could be dedicated to onsite erosion control measures. A telephone
number could be included on the appropriate fact sheets, encouraging people to report
observations of water quality violations. The city could provide copying and mailing services.
A citizen group working with the city could be responsible for composing the fact sheets. The
fact sheets could be distributed with city utility bills.
Because a fact sheet can be directed to specific audiences with a specific message, it could also
be used as the primary vehicle for the hazard-free community program. A fact sheet could be
sent to residences and businesses in the basin with the objective of decreasing individual
dependence on hazardous materials and increasing knowledge of alternatives to hazardous
materials.
Resource Signing and Interpretive Trail
This program includes placing signs at strategic locations to identify valuable environmental
resources. The signs would be produced and installed by the city. The design of the signs
could be developed by interested citizens, through a student contest or-a citizen group, with
final approval by the city. Signing should be integrated with the currently proposed trail plans
26
by the city parks department. A small number of suggested signs and locations are listed
below; however, the citizen group taking interest in this program should develop this program.
Signage Possible Locations
Entering Black River Basin I-405, SR-167, SW 43d Street, Empire Way S,
Puget Drive, 180th Avenue SE
Springbrook Creek Grady Way, SW 43d Street
(For the above two signs, the city should work cooperatively with King County and the
city of Kent to install signs in their jurisdictions. Interpretive signs could also be used to
emphasize the heron rookery located at the Black River pump station forebay.)
Panther Creek Wetland SR-167
Panther Creek Talbot Road
(An interpretive sign could be used at the proposed site of the ESGRW Plan spawning
channel to describe the project and the measures taken to reestablish salmon spawning.)
Black River SW 7th Street
(An interpretive sign could be used to describe the history of the Black River.)
These signs could also include wording such as This wetland is in your care or This is a
salmon stream.
Change and Recycle (CAR) Oil Committee
This program consists of organizing a committee to implement an education program for the
do-it-yourself oil changer. The committee would primarily consist of representatives from
automotive supply stores and related businesses; however, interested citizens could also be
involved. This program is planned for implementation by Communications Northwest in
Seattle under a possible public involvement and education grant from Ecology. (Puget Sound
Water Quality Authority 1991).
Possible methods for implementing the program include developing a brochure to be given to
consumers purchasing oil and other products from automotive supply stores. The brochure
would explain the consequences of improper disposal and direct the consumer to locations for
recycling. The city would finance the printing of the brochures, and the committee would be
responsible for authorship. Another method would be to develop a video to train automotive
supply store sales personnel in methods of encouraging oil recycling when consumers purchase
motor oil.
27
Newspaper Articles
Newspaper articles would be prepared on different aspects of the Black River basin plan to
help educate and inform residents about water quality issues in the basin and how their
voluntary actions can protect and improve water quality. A citizen group working with
support from the city could write the articles.
Stream Team Cleanup
This program is similar to the program developed by the city of Bellevue, with emphasis on
litter control in riparian corridors along streams. Teams would be formed for targeted streams
or sections of streams. The city would provide assistance during the initial organization of
teams, and the teams themselves would organize periodic cleanup dates and perform the
cleanup. The city would also provide assistance to obtain property access approvals.
Renton River Days Booth
The Renton River Days booth would provide information to the public on surface water
management in the city and the Black River basin. In addition, the booth would provide an
opportunity for Renton employees and interested citizens to participate by answering questions
regarding water quality, environmental resources, flooding problems, and how citizens can
help make things better.
Lawn Chemical Use
This program has the purpose of educating homeowners, gardeners, and small farmers about
the effects of their activities on water quality and promoting good gardening practices and the
proper use of chemicals. Informational materials have already been developed for the King
County area under a public education program called SOUND Gardening, SOUND Farming,
sponsored by Washington State University and King County Cooperative Extension (Puget
Sound Water Quality Authority 1991). These materials include 10 information sheets on
various aspects of gardening with consideration of water quality, a color poster on sound
gardening practices, a brochure, a slide-illustrated lecture, and buttons proclaiming "Good
gardening is SOUND gardening."
The city of Renton working with a citizens group would coordinate with Washington State
University and King County Cooperative Extension to obtain these materials and distribute
them or to make them available for citizens in the Black River basin.
The Renton Aquifer Protection Ordinance contains policies intended to mitigate adverse effects
of the use of chemicals by industry and small-scale agriculture. Although the ordinance was
adopted to provide protection for the Cedar River aquifer, which is outside the Black River
basin study area, certain provisions of the ordinance could be applied to control adverse effects
of chemical use within the Black River basin.
28
6. HISTORICAL DATA
To begin examining current water and sediment quality conditions in the Black River basin,
historical data collected in several previous studies were reviewed. Water and sediment quality
data typically consist of measurements of certain characteristics of the water and the sediment,
characteristics that are reliable indicators of the relative levels of contamination compared to
natural conditions. The quantifiable characteristics (or parameters) used to assess water quality
typically include stream flow (measured in cubic feet per second); water temperature; acidity
or basicity (pH); turbidity; conductivity; and concentrations of dissolved oxygen, suspended
solids, toxic metals, fecal coliform bacteria, and specific nutrients. The technical terms used
here in describing water and sediment chemistry are briefly explained in the glossary provided
at the end of this report.
Sediment quality parameters include grain size, toxic metals, organic carbon, petroleum
hydrocarbons, pesticides, herbicides, and numerous volatile and semivolatile organic
compounds. These terms are included in the glossary, and the typical sources and
environmental effects of each class of chemicals are discussed briefly in Chapter 7. Additional
information on the health of streams and water bodies is gained by measuring the abundance
and species diversity of certain bottom-dwelling aquatic insects and worms (or benthic
invertebrates).
Historical and recent measurements of all of these parameters in the waters and sediments of
the Black River basin are summarized in the data tables included in this document. For
comparison, water quality data from streams sampled in the Seattle metropolitan area, along
with state water quality criteria, are presented in Table 1. The complete water quality
assessment is provided in Volume 2, Appendix A.
HISTORICAL WATER QUALITY DATA
The following sources of water quality data were reviewed:
■ Municipality of Metropolitan Seattle - Metro routinely monitors water
quality on a monthly basis at station 0317, Metro's only routine
monitoring station in the Black River basin. It is located near the mouth
of Springbrook Creek adjacent to Longacres.
Water quality and flow data have been collected at station 0317 since
1977. In addition to routine monitoring, storm samples have been
collected at station 0317 on a few occasions each year since 1987.
Between 1977 and 1981, water quality and flow data were also collected
at two other stations on Springbrook Creek (F317 and H317) and at one
station on Mill Creek (E317).
■ Green River Community College - College students routinely monitor
water quality on a monthly basis at 11 stations in the Kent area. Water
quality data have been collected since January 1986 (GRCC 1992). Six
29
Table 1. Washington water quality criteria and water quality statistics for streams in the Seattle metropolitan area during
base flow and storm flow conditions
State Criteria(a) Base Flow(b) Storm Flow(b)
Class A Class AA Median Minimum Maximum Median Minimum Maximum
Temperature(degrees C) < 18.0 < 16.0 8.9 0.0 24.1 -- -- --
Dissolved oxygen(mg/L) > 8.0 > 9.5 10.9 3.0 13.8 -- -- --
pH 6.5-8.5 6.5-8.5 7.5 6.1 8.9 -- -- --
Conductivity(umhos/cm) -- -- 145 41 3,300 -- -- --
Turbidity(NTU) increase < 5 increase < 5 2.1 0.3 43 15.5 0.6 1,023
Total suspended solids(mg/L) -- -- 5.1 0.2 103 30.1 3.3 2,487
Ammonia nitrogen(ug/L) 5,590/764 5,590/764 17 < 10 2,400 34 1 251
Nitrate + nitrite nitrogen(ug/L) -- -- 700 13 5,590 680 168 2,356
Total phosphorus(ug/L) -- -- 22 < 8 640 125 9 1,558
Hardness(mg/L as CaCO3) -- -- -- -- -- 46 22.1 102.8
Copper(ug/L) 17.7/11.8 17.7/11.8 -- -- -- < 7.2 < 3.4 31
wo Lead(ug/L) 81.6/3.2 81.6/3.2 -- -- -- < 30 < 20 < 34
Zinc(ug/L) 117/106 117/106 -- -- -- 28 < 9 80
Fecal coliform bacteria(#/100 m 100 50 146 9 4,021 484 5 13,100
(a) Source:WAC-173-201A(11/25/92). Acute/chronic criteria for ammonia assume worst-case conditions of pH(8.0)and temperature(20 degrees C).
Acute/chronic criteria for metals assume a hardness of 100 mg/L as CaCO3.
(b) Source:Metro 1991. Base flow statistics are based on eleven samples collected monthly at 47 stream/river stations.Storm flow statistics are based on
five samples at 10 stream stations.
WQCRIT92.wg1
stations have been located in the Black River basin: two on Springbrook
Creek, two on Garrison Creek, and two on Mill Creek.
■ Washington Department of Ecology - Ecology (1992a) conducted
monthly water quality monitoring near the mouth of Mill Creek (station
09E070) from April 1984 to June 1990. Mill Creek water quality was
further investigated in the area near the Western Processing Superfund
site in 1984 (Yake 1985).
■ Western Processing - In conjunction with remedial activities at the
Western Processing Superfund site in Kent, water samples have been
collected monthly at station C3 since 1986.
■ Longacres - Water quality was monitored at Longacres for the Boeing
Company for one year beginning in June 1991. During that period,
water quality was monitored weekly in Springbrook Creek at SW 16th
Street (Metro station 0317) and at station 3 (the Longacres practice track
outfall to Springbrook Creek). Water quality samples were collected
less frequently during the same period at three other locations on the
Longacres site.
■ Sternco - In conjunction with the remedial investigation of the Sternco
site in Renton, water quality was monitored on one occasion in
Springbrook Creek below Mill Creek and in a wetland adjacent to the
property.
■ Blackriver Corporate Park - Water quality was monitored in the Black
River for the Blackriver Corporate Park draft environmental impact
statement (Renton 1990). In the summer of 1989, water samples were
collected on two occasions from the pump station forebay (P-1 pond)
and upstream of the forebay at Naches Avenue SW.
■ Earlington Park - Prior to the enlargement of the pump station forebay,
water quality was monitored in the Black River and Springbrook Creek
for the Earlington Park final environmental impact statement (Renton
1981). In October 1980, water samples were collected on three
occasions from four locations.
HISTORICAL SEDIMENT QUALITY DATA
The following sources of sediment quality data were reviewed:
■ Municipality of Metropolitan Seattle - Metro has monitored sediment
quality in Springbrook Creek at station 0317 each year since 1987.
Sediment samples are analyzed for metals and total solids.
31
■ Western Processing - In conjunction with remedial activities at the
Western Processing Superfund site in Kent, sediment quality data have
been collected from Mill Creek since 1986. Sediment samples have
been collected twice per year at stations C3 and C4.
An environmental assessment of Mill Creek in the vicinity of the
Western Processing facility was conducted in 1988/1989 for the city of
Kent (Converse 1989). Sediment and stream bank samples were
collected on one occasion for the analysis of heavy metals at several
locations along Mill Creek.
■ Sternco - In conjunction with the remedial investigation of the Sternco
site in Renton, sediment quality was monitored on one occasion in
Springbrook Creek below Mill Creek and in a wetland adjacent to the
property.
■ Blackriver Corporate Park - Dredge spoils from the 1984 enlargement of
the pump station forebay were sampled for the Blackriver Corporate
Park final environmental impact statement (Renton 1991). In July 1990,
soil samples were collected from six locations where dredge spoils were
deposited.
Heavy metals concentrations are presented for sediments from Springbrook Creek and Mill
Creek, for dredge spoils from the pump station forebay, and for soil from a wetland adjacent
to the Sternco site in Renton.
HISTORICAL BENTHIC INVERTEBRATE DATA
Metro sampled benthic invertebrates in Springbrook Creek at station 0317 each year from 1979
to 1989. During this period, samples were occasionally collected at other locations in
Springbrook Creek, Mill Creek, and the Green River.
SUMMARY OF EXISTING DATA
Existing data are summarized in Tables 2, 3, and 4.
Springbrook Creek and its tributaries are the primary sources of flow to the Black River,
comprising over 95 percent of the watershed. Springbrook Creek has poor water quality,
heavy metals contamination in sediments, and impoverished benthic invertebrate and fish
populations.
Chronic water quality problems include exceptionally low concentrations of dissolved oxygen;
high turbidity, and high levels of fecal coliform bacteria, suspended solids, total phosphorus,
and ammonia. Upstream sources appear to have significant impacts on Springbrook Creek
with respect to temperature, dissolved oxygen, ammonia, total phosphorus, and zinc. Sources
within the project area appear to be contributing to chronic problems with fecal coliform
32
Table 2. Historical water quality data summary for the Black River basin
Location Springbrook Springbrook Springbrook Mill Creek Mill Creek
near mouth below Mill Springs at mouth near mouth
Source Metro 1992 GRCC 1992 GRCC 1992 Ecology 1992 Landau 1991b
Station 0317 1 2 O9E070 C3
Begin Date 1/16/86 1/27/86 1/27/86 7/23/86 8/7/87
End Date 11/18/91 10/27/91 12/14/91 6/20/90 12/17/90
No.of Samples 87 58 72 48 39
Flow(cfs)
Mean 20.88 NA NA 14.7 7
Standard Deviation 14.75 NA NA 21.6 6
Minimum 1.96 NA NA 0.1 0
Maximum 82.60 NA NA 100.0 23
Temperature (degrees C)
Mean 11.0 12.0 10.6 12.4 13.7
Standard Deviation 4.0 4.0 3.1 7.3 4.8
Minimum 3.2 5.1 3.0 4.9 3.8
Maximum 19.0 21.7 18.2 19.0 22.4
%> 18.0* 7 11 1 15 15
Dissolved Oxygen (mg/L)
Mean 6.4 7.2 11.0 6.0 5.7
Standard Deviation 2.0 1.8 1.2 6.3 2.7
Minimum 2.1 4.4 7.9 1.6 2.0
Maximum 11.7 13.3 14.0 9.4 15.1
%< 8.0* 84 74 1 89 70
Turbitity(NTU)
Mean 26 42 16 22 31
Standard Deviation 21 34 30 11 18
Minimum 2.2 2.0 0.4 2.0 10
Maximum 170 126 197 43 104
%> 20 60 58 20 54 76
Suspended Solids (mg/L)
Mean 61 30 22 17 19
Standard Deviation 257 36 32.5 14 8
Minimum 5.1 3 <1 3 8
Maximum 2,384 172 190 62 38
Conductivity(umhos/cm)
Mean 246 259 218 303 379
Standard Deviation 109 80 26 152 404
Minimum 40 77 125 82 126
Maximum 530 408 333 595 2,390
Ammonia(mg/L as N)
Mean 0.34 0.49 0.09 0.81 1.05
Standard Deviation 0.24 0.31 0.10 0.39 0.33
Minimum 0.024 0.04 <0.02 0.04 0.64
Maximum 1.24 1.31 0.57 1.60 2
(Continued)
33
Table 2. Historical water quality data summary for the Black River basin (continued)
Location Springbrook Springbrook Springbrook Mill Creek Mill Creek
near mouth below Mill Springs at mouth near mouth
Source Metro 1992 GRCC 1992 GRCC 1992 Ecology 1992 Landau 1991b
Station 0317 1 2 09E070 C3
Begin Date 1/16/86 1/27/86 1/27/86 7/23/86 8/7/87
End Date 11/18/91 10/27/91 12/14/91 6/20/90 12/17/90
No.of Samples 87 58 72 48 39
Total Phosphorus (mg/L)
Mean 0.22 0.23 0.10 0.21 0.56
Standard Deviation 0.09 0.12 0.07 0.14 0.90
Minimum 0.089 0.07 0.04 0.02 0.05
Maximum 0.755 0.69 0.49 0.65 4.3
Fecal Coliform(#/100mL)
Mean (geometric) 534 264 178 228 NA
Minimum 13 37 30 14 NA
Maximum 6,500 1,200 4,300 13,000 NA
%> 100* 89 84 23 68 NA
Copper(ug/L)
Mean 9.8 12 10 10 59
Standard Deviation 5.9 5 2 11 72
Minimum <2 <10 <10 <1 <10
Maximum 29 30 20 47 253
Chronic Criterion* 7 7 7 12 12
% > Criteria* 45 NC NC 19 28
Lead (ug/L)
Mean 20 65 58 7 7
Standard Deviation 13 42 21 12 3
Minimum <1 <50 <50 <1 <3
Maximum 40 250 150 57 10
Chronic Criterion* 1.3 1.3 1.3 3.2 3.2
% > Criteria' NC NC NC 51 33
Zinc(ug/L)
Mean 101 140 20 279 328
Standard Deviation 57 120 40 231 277
Minimum <30 <10 <10 40 <20
Maximum 220 490 320 660 1,200
Chronic Criterion* 59 59 59 106 106
%> Criteria* 61 77 6 67 45
* Washington state water quality standards for Class A waters(WAC 173-201). Freshwater chronic
criteria for metals assume a mean hardness of 50 mg/L for Springbrook Creek and 100 mg/L
for Mill Creek. Undetected values are assumed to meet criteria. Percent exceeding criteria for Landau
(1991b)are based on data from 1/89 to 6/91.
NA = not available
NC = not calculable due to detection limit above criteria
NTU = nephelometric turbidity units
178II \histwat
34
Table 3. Historical sediment quality data summary for the Black River basin
Location Springbrook Springbrook Mill Creek Pump station Sternco
near mouth below Mill near mouth forebay wetland
Source Metro 1992 Seacor 1991 Landau 1991 Renton 1991 Seacor 1991
Stations 0317 SC-1,SC-2 C4 13101-13105 WL-1,-2,-3
Begin Date 9/29/87 10/1/90 8/7/87 07/19/90 10/1/90
End Date 9/3/91 10/1/90 9/17/90 7/19/90 10/1/90
No.of Samples 5 2 6 6 3
Cadmium(mg/kg dry wt.)
Mean 0.71 2.09 16.1 7.3 2.32
Standard Deviation 0.79 2.69 16.6 10.6 2.20
Minimum 0.30 <0.19 4.1 <1 1.00
Maximum 2.10 3.99 49 28 4.86
Chromium (mg/kg dry wt.)
Mean 15.9 29.0 39 32 30.5
Standard Deviation 5.4 18.9 18 45 1.7
Minimum 10.0 15.7 21 5 29.0
Maximum 22.9 42.4 64 120 32.4
Copper(mg/kg dry wt.)
Mean 13.0 15.4 57 32 50.7
Standard Deviation 5.5 3.7 28 36 33.6
Minimum 7.3 12.8 19 8 26.7
Maximum 20.8 18.0 96 97 89.1
Lead (mg/kg dry wt.)
Mean 8.0 4.12 13.6 26.3 76.7
Standard Deviation 4.8 0.28 6.5 42.6 104.4
Minimum 3.0 3.92 5.8 <10 10.7
Maximum 15.0 4.31 21.6 110 197
Mercury(mg/kg dry wt.)
Mean <0.02 <0.1 0.05 <0.15 0.17
Standard Deviation 0 0 0.03 0 0.02
Minimum <0.02 <0.1 0.01 <0.15 0.16
Maximum <0.02 <0.1 0.09 <0.15 0.19
Nickel(mg/kg dry wt.)
Mean 13.0 10.14 62 18 19.5
Standard Deviation 5.2 6.31 54 21 4.2
Minimum 7.0 5.68 23 <3 16.8
Maximum 19.0 14.6 180 57 24.4
Zinc(mg/kg dry wt.)
Mean 67.2 57.6 707 244 144
Standard Deviation 21.6 42.4 820 399 150
Minimum 37.0 27.6 55 20 53.7
Maximum 98.0 87.6 2500 1000 317
1781H\histsed
35
Table 4. Historical benthic invertebrate data summary for the Black River basin
Springbrook Creek near the mouth, Springbrook Creek below Mill Creek,
station 0317 Metro 1992 station G317 Metro 1992
Number of Number of Margalef Number of Number of Margalef
Date Organisms Groups Diversity Or anisms Groups Diversity
9/3/82 152 7 1.19 73 2 0.23
9/8/83 448 5 0.66 642 4 0.46
8/30/84 1,390 7 0.83 129 4 1.55
9/3/85 424 8 1.16 856 7 0.89
9/3/86 38 6 1.37 505 5 0.64
9/1/87 199 6 0.94 165 14 2.54
8/23/88 432 12 1.81 560 10 1.42
8/9/89 720 5 0.61 1,060 10 1.29
Mean 475 7 1.07 499 8 1.13
Margalef diversity index(Margalef 1968) _ (number of groups- 1)/ln(number of organisms)
178II \histben
36
bacteria and suspended solids. However, existing data are insufficient to allow for
identification of sources that are contributing to water quality problems in lower Springbrook
Creek.
Concentrations of cadmium, chromium, copper, nickel, and zinc in Mill Creek sediments
exceed North American criteria for freshwater sediments (Ecology 1991). Heavy metals
concentrations are significantly lower in sediments from Springbrook Creek than from Mill
Creek. Additionally, the forebay dredge spoils and wetland soils have generally higher heavy
metals concentrations than sediment near the mouth of Springbrook Creek. Although particle
size information is not available, a lower proportion of fine-grained sediments in Springbrook
Creek could account for lower concentrations of heavy metals.
The low diversity indices (i.e., nearly always less than 2) for benthic invertebrates measured at
both locations on Springbrook Creek indicate poor water and sediment quality. Furthermore,
more than 90 percent of the organisms were midges (Chironomidae) or earthworms
(Oligochaeta), known for their tolerance of low dissolved oxygen levels and fine sediment.
37
7. EXISTING WATER AND SEDIMENT QUALITY
Monitoring was undertaken for this study using a consistent set of parameters to provide a
picture of current water quality throughout the study area. Water and sediment samples were
collected at 14 stations (Figure 6). Station locations were chosen to characterize water and
sediment quality in Springbrook Creek, the Black River, and some of their major tributaries
and sources of drainage.
Water quality was monitored at 10 stations on six occasions from September 1991 through
April 1992. Two stations were located in Springbrook Creek (stations 3 and 7), and one was
located in the Black River (station 13). Other stations were used to identify pollutant sources
and loadings from the south Renton subbasin (station 8), the Rolling Hills subbasin (station 1),
the Panther Creek subbasin (station 2), and the valley subbasin (stations 4, 5, 9, and 10).
Water quality was monitored twice during base flow conditions and four times during storm
flow conditions. Base flow was sampled once in the dry season (base 1; September 26, 1991)
and once in the wet season (base 2; February 28, 1992). Storm flow was sampled four times
during the wet season (storm 1 through storm 4; November 19, 1991 through April 16, 1992).
Sediment quality was monitored once, during a base flow period in the dry season. Eight
stations were sampled in all, five of them located in Springbrook Creek (stations 3, 4, 6, 7,
and 12), one in the Black River (station 13), and two in major tributaries (stations 1 and 8).
Water samples were analyzed for the following chemical constituents and physical properties:
■ Temperature
■ pH
■ Dissolved oxygen
■ Turbidity
■ Conductivity
■ Total suspended solids
■ Total phosphorus
■ Soluble reactive phosphorus
■ Total persulfate nitrogen
■ Ammonia nitrogen
■ Nitrate+nitrite nitrogen
■ Copper
■ Lead
■ Zinc
■ Cadmium
■ Hardness
■ Fecal coliform bacteria.
Sediment samples were analyzed for the following classes of parameters:
■ Grain size
■ Conventional parameters
■ Metals
39
N
RENTON
13 U�q�Paa PH
Pumping
Station ''� t-
% Basin/Study Area
'•l �,r•• Boundary
Rolling
g SWietnSt. Hills
Drain
5 `
II ;, II
i 12 J
0t, P-9 Channel
r
,U - 1
I Panther
Creek
�`e0o i 8 Wetland
181
SW 341h St. '
9 .............
2
-�4
1
• SW 43rd St.
T4
Q � 1
' 167
IS.192nd S1.
LEGEND
------ Stream/Drainage Channel ', �springbrovk
Springs
.------------- Storm Drain Pipe
� Water Quality Monitoring �1
0 1 Station
t
Sediment Quality
0 Monitoring Station
0 1000 2000 3000
SCALE IN FEET
1
Black River Basin Water Quality Management Plan
Figure 6. Monitoring station locations
40
■ Semivolatile organic compounds
■ Low molecular weight polycyclic aromatic hydrocarbons (LPAH)
■ High molecular weight polycyclic aromatic hydrocarbons (HPAH)
■ Pesticides
■ Polychlorinated biphenyls (PCBs)
■ Herbicides
■ Volatile organic compounds.
WATER QUALITY MONITORING RESULTS
Water quality monitoring results are summarized in Tables 5, 6, and 7.
In the discussion of water quality results for each analyte, differences between monitoring
stations are identified for receiving waters, tributaries, and storm drains during base and storm
flow conditions. Receiving waters include upper Springbrook Creek (station 3), lower
Springbrook Creek (station 7), and the Black River (station 13). Monitored storm drains that
discharge to these receiving waters include the Kent drain (station 4), the 34th Street drain
(station 9), the P-9 channel (station 10), the 19th Street drain (station 5), and the Naches
Avenue drain (station 8). Monitored stations located upgradient of these storm drains include
the Rolling Hills drain (station 1), which is upstream of station 5, and Panther Creek (station
2), which is upstream of station 9.
In the sections below, results are compared with historical data for receiving waters and with
Washington state water quality criteria for Class A freshwaters (WAC 173-201). Ammonia
and metals results are compared to chronic criteria (4-day average) for base flow conditions
and to acute criteria (1-hour average) for storm flow conditions.
Temperature
High water temperatures can adversely affect cold water fish (i.e., salmon and trout). To
protect these resources, state water quality standards for Class A freshwaters require that
temperature increases resulting from nonpoint source activities shall not exceed 2.8°C, and the
maximum water temperature shall not exceed 18.3°C. These criteria were not exceeded at any
of the monitoring stations.
The maximum recorded temperature for all receiving water stations during this study was
15.1°C at station 3 on September 26, 1991 (base flow event 1). This temperature is nearly
70C cooler than the historical maximum of 21.7°C observed at this location. Historically,
temperatures in Springbrook Creek have typically exceeded 18°C in July and August. The
maximum recorded temperature at the other monitoring stations in this study was 15.7°C in
Panther Creek (station 2) during September. This result suggests that, similar to Springbrook
Creek, aquatic resources in Panther Creek may also experience high temperatures in July and
August.
41
Table 5. Mean water quality results for receiving waters in the Black River basin
Upper Springbrook Creek Lower Springbrook Creek Black River Pump Station
Station 3 Station 7 Station 13
Base Storm Base Storm Base Storm
Sample Data
Flow(cfs) -- -- 20 155 -- --
Analytes
Temperature(degrees C) 12.2 9.5 12.6 9.2 12.6 9.4
pH 7.24 6.94 7.06 6.92 6.99 6.94
Dissolved oxygen(mg/L) 6.8 8.0 6.0 7.9 7.0 8.6
Turbidity(NTU) 15 31 16 66 17 49
Conductivity(umhos) 241 101 305 100 314 110
Total suspended solids (mg/L) 5.0 42 5.6 70 6.6 27
Total phosphorus(mg/L) 0.137 0.214 0.162 0.258 0.211 0.155
Soluble reactive phosphorus(mg/L) 0.063 0.030 0.056 0.035 0.051 0.034
Total persulfate nitrogen(mg/L) 0.900 1.07 0.864 1.09 1.00 0.952
N Ammonia nitrogen(mg/L) 0.296 0.118 0.208 0.135 0.184 0.115
Nitrite + nitrate nitrogen(mg/L) 0.638 0.596 0.533 0.515 0.493 0.518
Copper,total(ug/L) 3.9 11.3 2.7 10.8 31.8 7.1
Lead,total(ug/L) 0.7 8.1 0.5 11.7 2.7 5.7
Zinc,total(ug/L) 117 58 20 67 100 35
Cadmium,total(ug/L) 0.2 0.5 0.2 0.7 0.3 0.2
Hardness(mg/L as CaCO3) 66.8 44.3 76.8 45.3 75.6 49.1
Fecal coliform bacteria(no./100 mL) 675 1113 607 962 205 958
NTU = nephelometric turbidity units
Black River(BRVRRCV.wgl)
Table 6. Mean water quality results for storm drains and tributaries in the southern portion of the Black River basin
Kent drain Panther Creek 34th Street drain
Station 4 Station 2 Station 9
Base Storm Base Storm Base Storm
Sample Data
Flow(cfs) 0.002 1.1 1.0 10 1.2 8.9
Analytes
Temperature(degrees C) 10.7 9.0 12.1 8.5 11.8 9.2
pH 7.49 6.78 7.96 7.23 6.84 7.20
Dissolved oxygen(mg/L) 6.6 7.7 10.1 11.0 8.2 10.0
Turbidity(NTU) 7.6 86 3.3 81 34 119
Conductivity(umhos) 448 56 225 78 326 96
Total suspended solids(mg/L) 2.2 73 2.7 73 12 100
Total phosphorus(mg/L) 0.101 0.350 0.043 0.609 0.134 0.125
Soluble reactive phosphorus(mg/L) 0.045 0.122 0.031 0.042 0.046 0.023
Total persulfate nitrogen(mg/L) 1.41 0.863 0.690 1.12 1.20 0.734
w Ammonia nitrogen(mg/L) 0.085 0.143 0.017 0.039 0.577 0.115
Nitrite + nitrate nitrogen(mg/L) 0.609 0.202 0.495 0.595 0.297 0.260
Copper,total(ug/L) 11.5 19.5 6.8 8.0 2.1 11.4
Lead,total(ug/L) 2.0 10.8 1.8 10.2 0.5 10.9
Zinc,total(ug/L) 66 154 43 41 9 48
Cadmium,total(ug/L) 0.4 1.9 0.1 0.1 0.1 0.1
Hardness (mg/L as CaCO3) 102.5 20.1 98.7 37.4 73.5 46.3
Fecal coliform bacteria(no./100 mL) 243 195 200 3020 3146 770
NTU = nephelometric turbidity units
Black River(BRVRBSNS.wgl)
Table 7. Mean water quality results for storm drains and tributaries in the northern portion of the Black River basin
P-9 channel Rolling Hills drain 19th Street drain Naches Avenue drain
Station 10 Station 1 Station 5 Station 8
Base Storm Base Storm Base Storm Base Storm
Sample Data
Flow(cfs) 1.7 7.5 -- -- 1.4 16 1.3 17
Analytes
Temperature(degrees C) 11.0 9.0 12.2 9.0 12.2 9.7 14.0 10.4
pH 6.92 6.85 7.42 6.86 7.16 7.14 6.85 6.99
Dissolved oxygen(mg/L) 1.7 5.2 9.9 10.8 8.9 10.1 5.6 8.2
Turbidity(NTU) 22 33 5.2 43 23 26 8.8 40
Conductivity(umhos) 357 130 355 93 212 121 211 92
Total suspended solids(mg/L) 7.2 15 2.65 49 4.8 29 2.6 44
Total phosphorus(mg/L) 0.095 0.112 0.029 0.117 0.070 0.082 0.135 0.147
Soluble reactive phosphorus(mg/L) 0.025 0.048 0.009 0.025 0.007 0.021 0.048 0.061
Total persulfate nitrogen(mg/L) 1.58 0.832 0.705 0.911 0.860 0.968 0.569 0.859
Ammonia nitrogen(mg/L) 1.13 0.140 0.093 0.072 0.194 0.103 0.185 0.070
Nitrite + nitrate nitrogen(mg/L) 0.107 0.226 0.707 0.473 0.603 0.531 0.315 0.494
Copper,total(ug/L) 5.1 5.8 5.7 15.8 8.0 8.7 4.1 7.7
Lead,total(ug/L) 0.5 5.5 1.4 39.5 1.6 11.5 1.0 16.1
Zinc,total(ug/L) 13 28 23 111 32 60 27 63
Cadmium,total(ug/L) 0.1 0.2 0.1 0.5 0.1 0.2 0.1 0.3
Hardness(mg/L as CaCO3) 68.2 62.9 176.1 44.0 125.6 45.3 89.5 47.0
Fecal coliform bacteria(no./100 mL) 464 98 373 2418 222 1381 780 974
NTU = nephelometric turbidity units
Black River(BRVRBSNN.wgl)
pH
Water quality standards for Class A freshwaters state that pH shall be within the range of 6.5
to 8.5, with human-caused variation limited to a range of less than 0.5 units. These criteria
were met at all receiving water stations, where pH ranged from 6.56 to 7.36. This observed
range is also similar to the historical range. At the other stations, the minimum pH criterion
was not met on only one occasion (i.e., pH of 5.93 at station 1 for storm event 1). Thus, pH
does not appear to be a problem in the Black River basin.
Dissolved Oxygen
Water quality standards for Class A freshwaters state that dissolved oxygen shall exceed 8.0
milligrams per liter (mg/L). At receiving water stations, dissolved oxygen concentrations
were typically below the criterion during base flow (5.6 to 8.1 mg/L) and near the criterion
during storm flow (7.1 to 9.6 mg/L). Historically, dissolved oxygen concentrations less than
5.0 mg/L have been observed in upper and lower Springbrook Creek. Thus, low dissolved
oxygen concentrations in Springbrook Creek and the Black River represent a water quality
problem that significantly impairs aquatic resources.
Low dissolved oxygen concentrations were measured during base flow conditions at the Kent
drain (6.6 mg/L at station 4), the P-9 channel (1.7 mg/L at station 10), and the Naches
Avenue drain (5.6 mg/L at station 8). Dissolved oxygen concentrations increased during
storm flow at these locations but often remained below the 8.0 mg/L criterion.
While low dissolved oxygen levels in storm drainage waters may exacerbate low dissolved
oxygen conditions in Springbrook Creek and Black River, the primary origin of low dissolved
oxygen concentrations in receiving waters of the basin is most likely organic solids that are
discharged from drains during storm flow, settle in the receiving waters, and then biologically
degrade and deplete oxygen during base flow conditions.
Turbidity
Water quality standards for Class A freshwaters state that turbidity shall not exceed 5
nephelometric turbidity units (NTU) over the background level when the background turbidity
is 50 NTU or less, and that turbidity increases shall not exceed 10 percent when background
turbidity is more than 50 NTU. These criteria were applied to receiving water stations by
comparing increases in turbidity downstream, progressing from station 3 to station 7 to station
13. Criteria were not exceeded at these stations during base flow conditions, when turbidity
levels ranged from 9 NTU in September to 22 NTU in February.
Turbidity criteria were exceeded during storm flow conditions, when turbidity levels increased
from upper to lower Springbrook Creek in November (16 to 46 NTU) and April (60 to 170
NTU). In addition, turbidity levels increased from 25 NTU in lower Springbrook Creek to 32
NTU in the Black River during the second storm event in January. The turbidity test results
observed in this study are similar to historical data.
45
Comparisons of mean turbidity values during storm flow conditions indicate that the following
drains and tributaries are primary sources of turbidity problems in receiving waters: Kent
drain (86 NTU at station 4), Panther Creek (81 NTU at station 2), 34th Street drain (119 NTU
at station 9), and 19th Street drain (121 NTU at station 5).
Conductivity
Water quality standards do not include conductivity criteria. Conductivity is proportional to
the concentration of dissolved solids and is useful for identifying potential sources of dissolved
pollutants. Conductivity can also be used for identifying areas of ground water discharge
during base flow conditions, because ground waters typically exhibit higher conductivity than
surface waters.
During summer base flow conditions, conductivity increased downstream in Springbrook
Creek from station 3 (258 µmhos per centimeter [cm]) to station 7 (341 µmhos/cm). Because
the discharge from storm drains was very low, ground water discharge to Springbrook Creek
was likely responsible for the increase in conductivity. Evidence for this conclusion is
provided by recent measurements of conductivity in ground water samples from shallow wells
(10 to 20 feet) at Longacres, which ranged from 373 to 857 µmhos/cm (Linders 1992 personal
communication; Totchko 1992 personal communication). Conductivity was typically lower at
all stations during storm flow events as a result of runoff having low dissolved solids content.
Total Suspended Solids
Water quality standards do not include suspended solids criteria. High concentrations of
suspended solids affect feeding activities of aquatic insects. Suspended solids also adversely
affect aquatic resources by settling, smothering benthic organisms, and consuming oxygen as
organic solids degrade. Furthermore, suspended solids adsorb pollutants such as heavy metals
and hydrocarbons.
Concentrations of suspended solids in receiving waters were low compared to historical data.
Mean concentrations were much lower during base flow (5-7 mg/L) than during storm flow
(27-70 mg/L). Mean concentrations during storm flow increased from 42 mg/L at upper
Springbrook Creek (station 3) to 70 mg/L at lower Springbrook Creek (station 7), but then
decreased to 27 mg/L at the Black River pump station (station 13). The decrease in suspended
solids concentrations from station 7 to station 13 indicates that the Black River pump station
forebay is acting as a sediment retention facility.
The increase in suspended solids concentrations downstream in Springbrook Creek is likely
due to both storm drain inflows and sediment entrainment from increased water current. Only
two storm drains had high mean suspended solids concentrations (i.e., 73 mg/L at station 4
and 100 mg/L at station 9). In addition, three storm flow water samples recently collected
from the north creek draining the Longacres site had a high mean total suspended solids
concentration (190 mg/L) (Sverdrup 1992). Since flow from these sources is estimated at less
than 10 percent of the flow in Springbrook Creek, sediment entrainment.also appears to be a
source of suspended solids in Springbrook Creek during storm flow.
46
Total Phosphorus
Phosphorus is typically the controlling nutrient for algal growth in freshwater. Nutrient
enrichment promotes excessive production of blue-green algae and bacteria, which results in
depressed oxygen levels from decomposition and respiration processes. With the exception of
toxicity criteria for ammonia, water quality standards do not include criteria for nutrients.
Total phosphorus concentrations in those receiving waters studied are high compared to other
streams in the metropolitan Seattle area (see Table 1). However, total phosphorus
concentrations have decreased significantly in Springbrook Creek and other streams in the
basin since 1979.
Mean total phosphorus concentrations increased from upper to lower Springbrook Creek
during base and storm flow conditions. Phosphorus concentrations were reduced in the Black
River pump station forebay during storm flow, but not during base flow. Thus, the forebay
removed suspended solids and total phosphorus during storm flow.
With two exceptions, mean total phosphorus concentrations were lower in the drains and
tributaries than in receiving waters. High total phosphorus concentrations were measured
during storm flow in the Kent drain (0.350 mg/L at station 4) and in Panther Creek (0.609
mg/L at station 2). The low mean phosphorus concentration at the 34th Street drain indicates
that phosphorus in Panther Creek is being removed in the Panther Creek wetland, at least
during storm flow conditions.
Phosphorus sources other than the Kent drain appear to be contributing to the increased total
phosphorus concentrations in Springbrook Creek. Likely sources include two creeks draining
from Longacres. The total phosphorus concentration observed in a water sample from the
south creek at Longacres was 1.8 mg/L, and the mean total phosphorus concentration observed
in three storm flow water samples from the north creek was 0.5 mg/L (Sverdrup 1992).
Soluble Reactive Phosphorus
Soluble reactive phosphorus is the available form of phosphorus for the growth of algae and
plants in streams. The presence of soluble reactive phosphorus in Springbrook Creek at
concentrations in excess of 0.05 mg/L indicates a highly enriched condition in which nutrients
are not limiting primary productivity.
In receiving waters, concentrations of soluble reactive phosphorus were lower during storm
flow than during base flow conditions. (Soluble reactive phosphorus concentrations are high
in base flow because ground water, which is the primary source of base flow, is typically high
in soluble reactive phosphorus in the region.) During base flow, the concentrations of soluble
reactive phosphorus were lower in drains and tributaries to Springbrook Creek than in the
receiving waters. During storm events this trend was reversed. These observations are
consistent with the complex processes of absorption, biological uptake, and release of
phosphorus that occurs in natural systems. The highest mean soluble phosphorus concentration
47
measured was at the Kent storm drain (0.122 mg/L at station 4), demonstrating the influence
of upstream discharges on Springbrook Creek.
Organic Nitrogen
Organic nitrogen concentrations are useful for evaluating the relative amount of organic
material in surface waters. Mean organic nitrogen concentrations were low in Springbrook
Creek during base flow (less than 0.2 mg/L) and during storm flow conditions (0.4 mg/L).
Seven routine water samples collected by Metro from Springbrook Creek in 1982 had a mean
organic nitrogen concentration of 0.6 mg/L (Metro 1992). Organic nitrogen concentrations in
receiving waters followed a pattern similar to that of total phosphorus concentrations. Mean
organic nitrogen concentrations increased from upper to lower Springbrook Creek during base
and storm flow conditions. Organic nitrogen concentrations were reduced as water passed
through the Black River pump station forebay during storm flows but not during base flows.
Thus, the forebay removed organic nitrogen as well as total phosphorus and suspended solids
during storm flows.
During base flow conditions, the Kent drain (station 4) exhibited the highest mean organic
nitrogen concentration (0.7 mg/L). The remaining drains and tributaries exhibited mean
organic nitrogen concentrations similar to levels observed in receiving waters.
Ammonia Nitrogen
Ammonia is the reduced, dissolved form of nitrogen that is directly taken up by plants and
microorganisms. Ammonia usually exists in an ionized state, but under conditions of high
temperature and pH, the proportion of un-ionized ammonia increases and can become toxic to
aquatic organisms. Water quality standards include ammonia criteria that are dependent on
temperature and pH. These criteria were not exceeded at any of the monitoring stations.
Ammonia concentrations were high in Springbrook Creek compared to other streams in the
metropolitan Seattle area (Metro 1990). With two exceptions, mean ammonia concentrations
in drains and tributaries did not substantially exceed ammonia levels in receiving waters.
Elevated ammonia concentrations were observed during base flow conditions at the 34th Street
drain (0.58 mg/L at station 9) and at the P-9 channel (1.13 mg/L at station 10).
Nitrate+Nitrite Nitrogen
Nitrate and nitrite are the oxidized, dissolved forms of nitrogen that also act as a nutrient and
energy source for plants and microorganisms. Nitrate+nitrite concentrations at all monitoring
stations were similar to those found in other streams in the metropolitan Seattle area (Metro
1990). Like ammonia, mean nitrate+nitrite concentrations during base flow conditions
decreased downstream as these nutrients were consumed by microorganisms. Nitrate+nitrite
concentrations were typically lower in drains and tributaries than in receiving waters. This
result is likely related to relatively large inputs of nitrate+nitrite .into receiving waters
upstream of the study area.
48
Copper
Because copper exerts varied toxic effects on aquatic organisms, water quality standards
include chronic and acute criteria for copper that depend on water hardness. Total copper
concentrations rarely exceeded chronic criteria at any station during base flow conditions.
During storm flows, copper concentrations typically exceeded acute criteria. Mean copper
concentrations were similar at upper and lower Springbrook Creek during base flow conditions
(3.9 and 2.7 micrograms per liter [µg/Q) and during storm flow events (11.3 and 10.8 µg/L).
Copper concentrations during storm flows were similar to historical mean concentrations in
Springbrook Creek. Drains and tributaries having higher mean copper concentrations than
Springbrook Creek during storm flows include the Kent drain (19.5 µg/L at station 4), the
Rolling Hills drain (15.8 µg/L at station 1), and the 34th Street drain (11.4 µg/L at station 9).
Lead
Water quality standards include chronic and acute criteria for lead that depend on water
hardness. Total lead concentrations rarely exceeded chronic criteria at any station during base
flow conditions. Lead concentrations increased substantially during storm flows, occasionally
exceeding acute criteria in receiving waters, drains, and tributaries. Mean lead concentrations
were similar at upper and lower Springbrook Creek during base flows (0.7 and 0.5 µg/L,
respectively) and during storm flows (8.1 and 11.7 µg/L, respectively). These levels are much
lower than historical levels, due in part to the more sensitive analytical procedures currently
available. Mean lead concentrations during storm flows were higher in all drains and
tributaries (except the P-9 channel) than in upper Springbrook Creek.
Zinc
Water quality standards also include chronic and acute criteria for zinc that depend on water
hardness. Total zinc concentrations rarely exceeded chronic criteria during base flows but
typically exceeded acute criteria during storm flows. The highest mean zinc concentration
during base flow was at upper Springbrook Creek (117 mg/L at station 3). This high level,
which is similar to historical levels, results from high zinc concentrations in Mill Creek.
Locations where mean zinc concentrations were substantially higher than those in upper
Springbrook Creek during storm flows include the Kent drain (154 µg/L at station 4) and the
Rolling Hills drain (111 µg/L at station 1).
Cadmium
Water quality standards also include chronic and acute criteria for cadmium that depend on
water hardness. During base flow conditions, cadmium concentrations were near the detection
limit and below chronic criteria. Acute criteria were exceeded in Springbrook Creek during
49
one storm event. The Kent drain (station 4) was the only location to exhibit mean cadmium
concentrations that exceeded those in Springbrook Creek.
Hardness
Water hardness is the sum of calcium and magnesium concentrations. Hardness is used in
determining toxicity of most heavy metals (toxicity is inversely proportional to hardness).
During base flow conditions, hardness increased downstream in Springbrook Creek from
drains that typically had harder water. Water hardness was lower at all stations during storm
flows than during base flows. (Hardness is high in base flow because ground water, which is
the primary source of base flow, is typically high in hardness in the region.)
Fecal Coliform Bacteria
High fecal coliform bacteria levels affect human health and recreational use of surface waters.
Accordingly, Washington water quality standards for Class A freshwaters state that fecal
coliform organisms shall not exceed a geometric mean value of 100 organisms per 100
milliliters (mL), with not more than 10 percent of samples exceeding 200 organisms per 100
mL. These criteria were exceeded at all monitoring stations.
Fecal coliform bacteria levels were higher in Springbrook Creek than levels observed
historically. Geometric mean values exceeded 600 organisms per 100 mL at all receiving
water stations except in the Black River during base flow. Mean values were similar in upper
and lower Springbrook Creek but were higher during storm flow than during base flow. Mean
values from receiving waters during base flow were exceeded in the 34th Street drain (3,146
organisms per 100 mL) and in the Naches Avenue drain (780 organisms per 100 mQ. Mean
values for receiving waters during storm flow were exceeded in Panther Creek (3,020
organisms per 100 mL), the Rolling Hills drain (2,418 organisms per 100 mQ, and the
Naches Avenue drain (974 organisms per 100 mL). Potential sources of fecal coliform
bacteria include animal feces (i.e., from pets and wildlife), septic systems in the Rolling Hills
and Panther Creek subbasins, and damaged sanitary sewer lines in the south Renton and valley
subbasins.
Hydraulic and Pollutant Loadings
Hydraulic and pollutant loading estimates were calculated for monitored drains and tributaries
to provide a comparison of the relative contributions of these sources to receiving waters in the
Black River basin (see Volume 2, Appendix A). For each event, pollutant loadings were
calculated for total suspended solids, total phosphorus, copper, lead, zinc, and fecal coliform
bacteria.
Hydraulic and pollutant loadings are based on a 24-hour event duration. The loadings are
calculated in this manner to provide estimates of the average daily water volume and pollutant
masses that are discharged from each hcation during base and storm_flow conditions. Given
the small number of samples collected, these loadings should be considered only as estimates.
50
However, the loading estimates provide a reasonable basis for evaluating relative differences
between subbasins. Despite the small number of samples, rainfall and flow conditions were
fairly representative of the observed annual variation.
Hydraulic loading estimates demonstrate the relatively small contribution of flow in the 34th
Street drain (station 9). This drain is located downstream of Panther Creek, which exhibited
hydraulic loading three times higher than loading in the 34th Street drain. This difference
indicates that much of the storm flow is bypassing the 34th Street drain via the Panther Creek
wetland. In addition, similar hydraulic loadings for the Rolling Hills drain (station 1) and 19th
Street drain (station 5) further indicate that a substantial amount of runoff from the east plateau
area is being diverted into the Panther Creek wetland and is not discharged directly into
Springbrook Creek.
These pollutant loading estimates demonstrate the following:
■ The negligible contribution of base flows to the overall mass of
pollutants discharged to Springbrook Creek
■ The minor contribution of the P-9 channel (station 10) relative to other
sources
■ The high suspended solids loadings at all stations except the Kent drain
(station 4) and the P-9 channel (station 10)
■ The high phosphorus loading in Panther Creek (station 2), with much of
the phosphorus arising from the Panther Creek subbasin apparently
removed as these waters pass through the Panther Creek wetland
■ The high copper, lead, and zinc loadings in the Rolling Hills drain
(station 1) and 19th Street drains (stations 1 and 5)
■ The high fecal coliform bacteria loadings in runoff from the east plateau
(i.e., in Panther Creek, station 2; and Rolling Hills drain, station 1).
SEDIMENT QUALITY MONITORING RESULTS
Sediment quality monitoring results are summarized in Table 8. The results are discussed
separately below for each group of analytes. This discussion includes comparisons between
monitoring stations using existing information and sediment quality criteria established for
protecting aquatic resources. For each group of analytes the results are discussed with respect
to differences among monitoring stations, existing information, and sediment criteria.
As part of an effort to develop standards for contaminated freshwater sediments, Ecology
(1991) has summarized sediment criteria from various North American sources. Sediment
quality monitoring results are compared to the following three sources:
51
Table 8. Sediment quality results based on dry weight for Black River basin,September 1991
Station
1 3 4 6 7 8 12 13
Grain Size(percent)
Pebble(>4750 u) 3 0 M 3 35 0 7 2 0
Granule(4750-2000 u) 9 1 M 4 22 0 11 1 0
Very coarse sand(2000-850 u) 21 3 M 5 13 3 18 2 1
Coarse sand(850-425 u) 41 11 M 21 17 7 28 3 0
Medium sand(425-250 u) 20 17 M 41 10 10 16 3 1
Fine sand(250-106 u) 2 23 M 13 2 25 10 7 36
Very fine sand(106-75 u) 0 8 M 2 0 4 1 4 25
Very fine sand(75-62.5 u) 0 4 M 1 0 3 1 3 12
Coarse silt(62.5-31.2 u) 1 12 M 2 1 28 3 28 14
Medium silt(31.2-15.6 u) 1 8 M 4 0 5 2 11 3
Fine silt(15.6-7.8 u) 1 6 M 2 0 4 2 12 1
Very fine silt(7.8-3.9 u) 1 3 M 2 0 4 1 9 2
Clay(3.9-1.9 u) 0 2 M 0 0 3 0 6 1
Clay(1.9-0.9 u) 0 1 M 0 0 2 0 3 1
Clay(<0.9 u) 0 2 M 0 0 2 0 4 0
Silt and clay(<62.5 u) 4 34 M 10 1 48 8 73 22
Conventional Parameters
Solids(percent) 76.15 45.62 M 45.32 82.56 20.2 58.21 16.09 54.39
Volatile solids(percent) 1.28 5.04 M 3.66 0.83 8.93 4.99 15.84 3.68
Total organic carbon(percent) 0.62 1.40 M 1.49 0.33 16.85 4.86 4.61 1.94
Total petroleum
hydrocarbons(mg/kg) 85 600 280 22 630 2700 820 330
Metals(mg/kg)
Arsenic 4.6 J 11.25 JM 12.4 J 3.70 J 30.20 J 10.9 J 30.7 J 6.83 J
Cadmium 0.3 31.3 M 2.8 0.2 4.2 1.3 9.1 1.5
Copper 15.5 55.9 M 32.8 12.3 61.1 61.0 81.6 23.2
Lead 12.5 J 43.2 JM 26.7 J 4.2 J 45.9 J 246 J 76.7 J 16.3 J
Mercury 0.1 J 0.14 JM 0.10 J 0.04 J 0.23 J 0.13 J 0.30 J 0.07 J
Zinc 79 513 M 250 50.7 429 295 610 152
Semivolatile Organics(ug/kg)
Phenol 140 U 200 U 150 U 130 U 410 U 730 U 410 U 190 U
bis(2-Chloroethyl)ether 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
2-Chlorophenol 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
1,3-Dichlorobenzene 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
1,4-Dichlorobenzene 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
Benzyl alcohol 350 U 500 U 380 U 330 U 1000 U 1800 U 1000 U 460 U
(continued)
52
Table 8. Sediment quality results based on dry weight for Black River basin,September 1991(page 2 of 5)
Station
1 3 4 6 7 8 12 13
Semivolatile Organics(ug/kg)
1,2-Dichlorobenzene 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
2-Methylphenol 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
bis(2-Chloroisopropyl)ether 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
4-Methylphenol 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
n-Nitroso-di-n-propylamine 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
Hexachloroethane 140 U 200 U 150 U 130 U 410 U 730 U 410 U 190 U
Nitrobenzene 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
Isophorone 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
2-Nitrophenol 350 U 500 U 380 U 330 U 1000 U 1800 U 1010 U 460 U
2,4-Dimethylphenol 140 U 200 U 150 U 130 U 410 U 730 U 410 U 190 U
Benzoic acid 700 U 1000 U 7.50 U 660 U 2100 U 3600 U 2000 U 930 U
bis(2-Chloroethoxy)methane 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
2,4-Dichlorophenol 210 U 299 U 225 U 200 U 620 U 1100 U 200 U 280 U
1,2,4-Trichlorobenzene 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
4-Chloroaniline 210 U 299 U 225 U 200 U 620 U 1100 U 200 U 280 U
Hexachlorobutadiene 140 U 200 U 150 U 130 U 410 U 730 U 410 U 190 U
4-Chloro-3-methylphenol 140 U 200 U 150 U 130 U 410 U 730 U 410 U 190 U
2-Methylnaphthalene 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
Hexachlorocyclopentadiene 350 U 500 U 380 U 330 U 1000 U 1800 U 1000 U 460 U
2,4,6-Trichlorophenol 350 U 500 U 380 U 330 U 1000 U 1800 U 1000 U 460 U
2,4,5-Trichlorophenol 350 U 500 U 380 U 330 U 1000 U 1800 U 1000 U 460 U
2-Chloronaphthalene 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
2-Nitroaniline 350 U 500 U 380 U 330 U 1000 U 1800 U 1000 U 460 U
Dimethyl phthalate 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
3-Nitroaniline 350 U 500 U 380 U 330 U 1000 U 1800 U 1000 U 460 U
2,4-Dinitrophenol 700 U 1000 U 750 U 660 U 2100 U 3600 U 1000 U 930 U
4-Nitrophenol 350 U 500 U 380 U 330 U 1000 U 1800 U 1000 U 460 U
Dibenzofuran 70 U 100 U 75 U 66 U 210 U 300 J 200 U 93 U
2,4-Dinitrotoluene 350 U 500 U 380 U 330 U 1000 U 1800 U 1000 U 460 U
2,6-Dinitrotoluene 350 U 500 U 380 U 330 U 1000 U 1800 U 1000 U 460 U
Diethylphthalate 63 J 100 U 75 U 66 U 210 U 360 U 200 U 93 U
4-Chlorophenyl-phenylether 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
4-Nitroaniline 350 U 500 U 380 U 330 U 1000 U 1800 U 1000 U 460 U
4,6-Dinitro-2-methylphenol 700 U 1000 U 750 U 660 U 2100 U 3600 U 1000 U 930 U
n-Nitrosodiphenylamine(1) 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
4-Bromophenyl-phenylether 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
Hexachlorobenzene 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
Pentachlorophenol 350 U 500 U 380 U 330 U 1000 U 1800 U 1000 U 460 U
Carbazole 70 U -- -- 66 U 210 U 1400 -- 93 U
(continued)
53
Table 8. Sediment quality results based on dry weight for Black River basin,September 1991(page 3 of 5)
Station
1 3 4 6 7 8 12 13
i
Semivolatile Organics(ug/kg)
Di-n-butylphthalate 70 U 120 JM 120 J 66 U 210 U 360 U 280 J 93 U
Butylbenzylphthalate 70 U 105 JM 75 J 66 U 210 U 360 U 270 93 U
3,3'-Dichlorobenzidine 350 U 500 U 380 U 330 U 1000 U 1800 U 1000 U 460 U
bis(2-Ethylhexyl)phthalate 78 2250 JM 1300 J 66 U 3100 4100 6000 J 1200 U
Di-n-octyl phthalate 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
LPAH(ug/kg)
Naphthalene 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
Acenaphthylene 70 U 100 U 75 U 66 U 210 U 360 U 200 U 93 U
Acenaphthene 70 U 100 U 75 U 66 U 210 U 410 200 U 93 U
Fluorene 70 U 100 U 75 U 66 U 210 560 200 U 93 U
Phenanthrene 160 235 M 120 66 U 230 U 8100 6.50 160
Anthracene 70 U 100 U 75 U 66 U 210 U 1400 200 U 93 U
Total LPAH 160 235 120 66 U 210 10470 650 160
HPAH(ug/kg)
F7uoranthene 240 615 M 320 66 U 600 15000 1600 370
Pyrene 170 525 M 260 66 U 500 9300 1400 290
Benzo(a)anthracene 81 185 M 99 66 U 160 J 4800 420 170
Chrysene 95 385 M 180 66 U 350 5900 960 340
Benzo(b+k)fluoranthene 130 580 M 280 66 U 560 3800 1300 180
Benzo(a)pyrene 72 240 M 120 66 U 210 U 4800 620 150
Dibenzo(a,h)anthracene 70 U 100 U 75 U 66 U 210 U 690 200 U 93 U
Benzo(g,h,i)perylene 70 U 155 M 75 U 66 U 210 U 2200 630 93 U
Indeno(1,2,3-c,d)pyrene 70 U 19.5 M 110 66 U 210 U 3000 700 93 U
Total HPAH 788 2880 1369 66 2010 49490 7630 1500
Pesticides(u")
Alpha-BHC 4.0 U 5.0 U 5.0 U 5.0 U 10 U 5.0 U 11 U 5.0 U
Beta-BHC 4.0 U 5.0 U 5.0 U 5.0 U 10 U 5.0 U 11 U 5.0 U
Delta-BHC 4.0 U 5.0 U 5.0 U 5.0 U 55 U 6.5 11 U 5.0 U
Gamma-BHC(Lindane) 4.0 U 5.0 U 5.0 U 5.0 U 10 U 5.0 U 11 U 5.0 U
Heptachlor 4.0 U 5.0 U 5.0 U 5.0 U 10 U 5.0 U 11 U 5.0 U
Aldrin 4.0 U 12 U 5.0 U 5.0 U 15 U 5.0 U 18 U 5.0 U
Heptachlor epoxide 4.0 U 5.0 U 5.0 U 5.0 U 10 U 5.0 U 11 U 5.0 U
Endosulfan I 4.0 U 5.0 U 5.0 U 5.0 U 10 U 5.0 U 11 U 5.0 U
Dieldrin 8.0 10 U 10 U 10 U 20 U 10 U 22 U 10 U
4,4'-DDE 8.0 10 U 10 U 10 U 20 U 10 U 22 U 10 U
Endrin 8.0 10 U 10 U 10 U 20 U 18 22 U 10 U
Endosulfan II 8.0 10 U 10 U 10 U 20 U 10 U 22 U 10 U
(continued)
54
Table 8. Sediment quality results based on dry weight for Black River basin,September 1991 (page 4 of 5)
Station
1 3 4 6 7 8 12 13
Pesticides(ug/kg)
4,4'-DDD 8.0 10 U 10 U 10 U 170 6.1 J 22 U 5.5 J
Endosulfan sulfate 8.0 10 U 10 U 10 U 20 U 10 U 22 U 10 U
4,4'-DDT 8.0 10 U 10 U 10 U 12 J 10 U 22 U 10 U
Methoxychlor 40 U 50 U 50 U 50 U 100 U 50 U 110 U 50 U
Endrin ketone 8.0 10 U 10 U 10 U 20 U 33 22 U 10 U
Endrin aldehyde 8.0 10 U 10 U 10 U 20 U 10 U 22 U 10 U
Gamma-chlordane 4.0 U 5.0 U 5.0 U 5.0 U 190 5.0' U 11 U 6.1
Alpha-chlordane 4.0 U 5.0 U 5.0 U 5.0 U 170 17 11 U 3.3 J
Toxaphene 400 U 500 U 500 U 500 U 1000 U 500 U 1100 U 500 U
PCBs(ug/kg)
Aroclor-1242/1016 80 U 100 U 100 U 100 U 200 U 100 U 220 U 100 U
Aroclor-1248 80 U 100 U 100 U 100 U 200 U 100 U 220 U 100 U
Aroclor-1254 80 U 100 U 100 U 100 U 220 100 U 220 U 100 U
Aroclor-1221 160 U 200 U 200 U 200 U 400 U 200 U 440 U 200 U
Aroclor-1232 80 U 100 U 100 U 100 U 200 U 100 U 220 U 100 U
Aroclor-1260 80 U 100 U 100 U 100 U 200 U 100 U 220 U 100 U
Herbicides(ug/kg)
Silvex 2.5 U 3.0 U 3.0 U 2.5 U 10 U 30 U 3.0 U 6.0 U
2,4,5-T 2.5 U 3.0 U 3.0 U 2.5 U 5.0 U 6.0 U 3.0 U 4.0 U
Dinoseb 2.5 U 4.0 U 4.0 U 2.5 U 5.3 U 4.0 U 4.0 U 8.1 U
Dicamba 2.5 U 3.0 U 3.0 U 2.5 U 5.0 U 2.5 U 3.0 U 2.5 U
2,4-D 40 U 13 U 13 U 40 U 170 U 380 U 13 U 38
2,4-DB 45 U 50 U 50 U 45 U 210 U 260 U 50 U 190 U
Dalapon 700 U 340 U 340 U 700 U 970 U 200 U 340 U 680 U
Volatile Organics(ug/kg)
Chloromethane 6.1 U 3.6 U 2.8 U 5.9 U 34 U 6.8 U 12 24 U
Bromomethane 3.7 U 3.6 U 2.8 U 3.5 U 20 U 4.1 U 9.8 U 14 U
Vinyl chloride 3.7 U 5.4 U 4.1 U 3.5 U 20 U 4.1 U 15 U 14 U
Chloroethane 3.7 U 5.4 U 4.1 U 3.5 U 20 U 4.1 U 15 U 14 U
Methylene chloride 2.4 U 1.3 JM 1.3 J 2.3 U 11 J 1.5 J 4.1 J 6.1 J
Acetone 6.1 U 16.5 M 15 4.3 J 58 J 6.8 J 95 53 J
Carbon disulfide 2.4 U 3.6 U 2.8 U 2.3 U 14 U 2.7 U 9.8 U 9.5 U
1,1-Dichloroethene 2.4 U 1.8 U 1.4 U 2.3 U 14 U 2.7 U 4.9 U 9.5 U
1,1-Dichloroethane 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
trans-1,2-Dichloroethene 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
cis-1,2-Dichloroethene 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
Chloroform 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
1,2-Dichloroethane 1.2 U 3.6 U 2.8 U 1.2 U 6.8 U 1.4 U 9.8 U 4.7 U
(continued)
55
Table 8. Sediment quality results based on dry weight for Black River basin,September 1991(page 5 of 5)
Station
1 3 4 6 7 8 12 13
Volatile Organics(ug/kg)
2-Butanone 9.2 U 14 U 10 U 8.8 U 51 U 10 U 37 U 36 U
1,1,1-Trichloroethane 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
Carbon tetrachloride 1.2 U 3.6 U 2.8 U 1.2 U 6.8 U 1.4 U 9.8 U 4.7 U
Vinyl acetate 1.2 U 3.6 U 2.8 U 1.2 U 6.8 U 1.4 U 9.8 U 4.7 U
Bromodichloromethane 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
Trichlorofluoromethane 1.2 U 3.6 U 2.8 U 1.2 U 6.8 U 1.4 U 9.8 U 4.7 U
1,2-Dichloropropane 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
trans-1,3-Dichloropropene 1.2 U 3.6 U 2.8 U 1.2 U 6.8 U 1.4 U 9.8 U 4.7 U
Trichloroethene 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
Dibromochloromethane 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
1,1,2-Trichloroethane 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
Benzene 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
cis-1,3-Dichloropropene 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
2-Chlororethylvinylether 1.2 U 3.6 U 2.8 U 1.2 U 6.8 U 1.4 U 9.8 U 4.7 U
Bromoform 1.2 U 5.4 U 4.1 U 1.2 U 6.8 U 1.4 U 15 U 4.7 U
4-Methyl-2-pentanone 2.4 U 3.6 U 2.8 U 2.3 U 14 U 2.7 U 9.8 U 9.5 U
2-Hexanone 4.9 U 3.6 U 2.8 U 4.7 U 27 U 5.5 U 9.8 U 19 U
Tetrachloroethene 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
1,1,2,2-Tetrachloroethane 1.2 U 3.6 U 2.8 U 1.2 U 6.8 U 1.4 U 9.8 U 4.7 U
Toluene 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 2.3 67 4.7 U
Chlorobenzene 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
Ethylbenzene 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 2.2 J 4.9 U 4.7 U
Styrene 1.2 U 1.8 U 1.4 U 1.2 U 6.8 U 1.4 U 4.9 U 4.7 U
Total xylenes 2.4 U 3.6 U 2.8 U 2.3 U 14 U 25 9.8 U 9.5 U
1,1,2-Trichloro-1,2,2-
trifluoroethane 6.1 U 3.6 U 2.8 U 5.9 U 34 U 6.8 U 9.8 U 24 U
U =compound was analyzed for but not detected at the given detection limit.
J =estimated value when result is less than specified detection limit,or spectral match is low,or blank is
contaminated,or quality control objectives were not met.
M =value of analyte is a mean of field duplicates.
LPAH=low molecular weight polycyclic aromatic hydrocarbons
HPAH= high molecular weight polycyclic aromatic hydrocarbons
PCB =polychlorinated biphenyl
Black River(SEDS91.wgl)
56
■ Ontario provincial sediment quality guidelines for metals and organic
compounds having low to severe effects on benthic organisms (Persaud
et al. 1992)
■ U.S. Environmental Protection Agency (U.S. EPA) interim sediment
criteria for nonpolar organic compounds having chronic effects on
benthic organisms (U.S. EPA 1988b)
■ U.S. EPA Region 5 guidelines for pollutional classification of freshwater
harbor sediments (U.S. EPA 1977).
In some cases, when freshwater sediment criteria are lacking, results are compared to
Washington state marine sediment criteria (WAC 173-204). Marine sediment criteria for other
analytes are higher than the low and chronic effect criteria for freshwater sediments, which
suggests that exceedance of criteria established for marine sediment would adversely affect
aquatic resources in freshwaters.
Grain Size
Large grain size sediments (i.e., granules and pebbles greater than 2 millimeters [mm]) are
preferred habitat for aquatic insects and fish. The only sediment sample having a
predominance of large grain sizes (57 percent) was from station 6, Springbrook Creek at SW
16th Street. In contrast, nearby station 12 had the highest percentage of fine-grained sediment
(73 percent silt and clay). Other stations on Springbrook Creek had silty-sand sediments
where the fines content ranged from 10 to 48 percent. Coarse sand was the predominant grain
size in the Rolling Hills and Naches Avenue storm drains (stations 1 and 8, respectively).
Conventional Parameters
High levels of total volatile solids and total organic carbon are indicative of pollution and are
detrimental to aquatic organisms, because the decomposition of these constituents results in
depressed oxygen levels in the sediment and water. Unpolluted sediments have total volatile
solids levels less than 5 percent, and heavily polluted sediments have total volatile solids levels
greater than 8 percent (U.S. EPA 1977). Applying these criteria, sediments in Springbrook
Creek at the mouth (station 7) and below the P-9 channel (station 12) are heavily polluted.
Total organic carbon levels in excess of 10 percent have a severe effect on aquatic organisms
(Persaud et al. 1992). This total organic carbon criterion was exceeded only at the mouth of
Springbrook Creek (17 percent at station 7). Total organic carbon levels at the Rolling Hills
drain (station 1) and in Springbrook Creek at SW 16th Street (station 6) exceeded the lowest
effect criterion of 1 percent (Persaud et al. 1992).
Total petroleum hydrocarbons (TPH) provide a gross measure of hydrocarbon contamination,
which is typically used in determining options for disposing of excavated soils and sediment on
land. TPH concentrations were highest in the Naches Avenue storm drain (2,700 milligrams
per kilogram [mg/kg] at station 8). TPH concentrations exceeded 200 mg/kg at all stations
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except stations 1 and 6. Further discussion of TPH results is provided in the sediment disposal
options section.
Metals
Heavy metals exert varied toxic effects on aquatic organisms. High levels of all metals
analyzed except mercury were observed in sediment samples from Springbrook Creek. Metal
concentrations were generally higher in those samples having a high percentage of fines. High
levels of metals were also observed in sediment from the Naches Avenue storm drain, but not
in sediment from the Rolling Hills drain or the Black River.
Arsenic concentrations were highest in silty sediments from Springbrook Creek at stations 7
and 12 (30 mg/kg). Springbrook Creek above SW 43d Street (station 3) and below SW 41st
Street (station 4) as well as the Naches Avenue drain (station 8) also had arsenic concentrations
that exceeded the criterion for heavily polluted sediments (8 mg/kg) and the lowest effect
criterion (6 mg/kg).
The sediment concentration of cadmium was very high at station 3 in upper Springbrook Creek
(31 mg/kg), exceeding the severe effect criterion of 10 mg/kg (Persaud et al. 1992). This
level also exceeded the mean concentration in Mill Creek (16 mg/kg), which is contaminated
with cadmium from the Western Processing Superfund site. Other sediment samples exhibited
moderate levels of cadmium that were generally higher in silty sediments and were similar to
historical data.
Sediments were heavily contaminated with copper (greater than 50 mg/kg) at three of six
stations in Springbrook Creek (stations 3, 7, and 12) and in the Naches Avenue storm drain
(station 8). Copper concentrations at these locations were similar to those in Mill Creek,
which is also heavily contaminated. Copper concentrations did not exceed the severe effect
criterion (110 mg/kg) but typically exceeded the lowest effect criterion (16 mg/kg) (Persaud et
al. 1992).
In Springbrook Creek, sediments were moderately contaminated with lead (between 40 and 60
mg/kg) at stations 3 and 7 but exhibited heavy contamination (greater than 60 mg/kg) at station
12. Lead concentrations appear to be associated with the high fines content at these locations.
The lead content of sediment from upper Springbrook Creek (station 3) was higher than the
maximum lead concentration reported for sediment in Mill Creek, suggesting that sources in
Kent are contributing sediment to Springbrook Creek that is more contaminated with lead than
sediment in Mill Creek. The highest lead concentration was observed in sediment from the
Naches Avenue storm drain (246 mg/kg at station 8), and is likely related to the high
petroleum levels observed at this station (see section on conventional parameters above). Lead
concentrations did not exceed the severe effect criterion (250 mg/kg) but exceeded the lowest
effect criterion (31 mg/kg) (Persaud et al. 1992) at stations 3, 7, 8, and 12.
Mercury concentrations were low in all sediment samples but were slightly above the lowest
effect criterion (0.2 mg/kg) at stations 7 and 12 in Springbrook Creek. Mercury
concentrations tended to increase with ,percent fines and were elevated above historical levels.
58
Sediments were heavily contaminated with zinc (greater than 200 mg/kg) and exceeded the
lowest effect criterion (120 mg/kg) at all Springbrook Creek locations except station 6 and in
the Naches Avenue drain (station 8). Zinc concentrations did not exceed the severe effect
criterion of 820 mg/kg (Persaud et al. 1992). Zinc sediment concentrations tended to increase
with percent fines and were comparable to historical levels.
Semivolatile Organic Compounds
Semivolatile organic compounds are a group of organic chemicals that includes phenols,
nonvolatile chlorinated hydrocarbons, halogenated ethers, phthalates (plasticizers), and
polycyclic aromatic hydrocarbons (PAHs). Only phthalates and PAHs were detected in the
sediment samples. (PAH results are discussed in the following section.) There are no
published criteria for phthalates in freshwater sediments. However, criteria have been
established by Ecology for phthalates in marine sediments (WAC 173-204). The criterion for
bis(2-ethylhexyl)phthalate was exceeded at stations 3, 4, 8, and 12. The criterion for
butylbenzylphthalate was exceeded at stations 4 and 12.
Polycyclic Aromatic Hydrocarbons
PAHs are nonpolar, semivolatile organic compounds whose toxicity to aquatic organisms
depends on the organic carbon content of the sediment. PAHs were detected in all sediments
except the coarse-grained sediment from station 6. PAH concentrations were much higher at
the Naches Avenue drain (station 8) than at the other monitoring stations. PAH concentrations
in Springbrook Creek were highest below the P-9 channel (station 12).
PAH results were converted to units of mg/kg organic carbon and compared to available
interim freshwater sediment criteria reported by U.S. EPA (1988b). The criterion for
phenanthrene was exceeded at the Naches Avenue drain (station 8). In addition,
concentrations of fluoranthene and chrysene at station 8 exceeded marine sediment criteria
(WAC 173-204).
Organochlorine Pesticides
Organochlorine pesticides are resistant to environmental degradation and are commonly found
in sediments many years after their use has ceased. Some of these pesticides were detected at
the mouth of Springbrook Creek (station 7), below the Black River pump station (station 13),
and in the Naches Avenue drain (station 8).
Detectable concentrations of pesticides that exceeded the lowest effect criterion (Persaud et al.
1992) include endrin at station 8, DDT and its derivative DDD at station 7, and chlordane at
stations 7 and 8. Organochlorine pesticide concentrations did not exceed severe effect criteria.
59
Polychlorinated Biphenyls
PCBs, which include several Aroclor formulations, are resistant to environmental degradation.
Historically their use has been widespread. One formulation (Aroclor 1254) was detected at
the mouth of Springbrook Creek (220 jig/kg at station 7) at a level just above the detection
limit. PCB detection limits exceeded the lowest effect criterion (5-60 jig/kg) but not the
severe effect criterion (24-150 mg/kg organic carbon) identified by Persaud et al. (1992).
Herbicides
The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) was detected at low levels in sediments
below the Black River pump station (38 µg/kg at station 13). There are no sediment quality
criteria established for 2,4-D.
Volatile Organic Compounds
Several volatile organic compounds that are typically used in solvents were detected in the
sediment samples. Methylene chloride and acetone concentrations were highest at stations 7
and 12 in Springbrook Creek and at station 13 below the Black River pump station.
Chloromethane and toluene were also detected at station 12. Toluene, ethylbenzene, and
xylene were detected in sediment from the Naches Avenue storm drain (station 8). The
concentrations detected are listed in Table 8. Ecology (1991) presents sediment quality criteria
for only three of the volatile organic compounds detected in the sediment samples: methylene
chloride (1,260 mg/kg carbon), toluene (5,250 mg/kg carbon), and ethylbenzene (11,000
mg/kg carbon). Applying the appropriate unit conversion, the highest concentration of a
volatile organic compound detected in the sediment samples was 2 mg/kg carbon.
Sediment Disposal Options
Action 6, defined in Chapter 16 of this plan, recommends that the city expand its existing
program to improve the functioning of existing stormwater systems. Such a program would
include routine removal of sediment from storm drains and transport of these materials to
approved disposal sites.
Sediment quality results are compared to existing state regulations in determining where
dredged sediments may be disposed of on land. Regulations considered in this comparison
include the Model Toxics Control Act (WAC 173-340) and the dangerous waste regulations
(WAC 173-303).
The Model Toxics Control Act has established surface water and ground water cleanup levels
for hazardous waste sites. Surface water cleanup levels are effectively the same as water
quality standards (WAC 173-201). Freshwater sediment cleanup levels have not yet been
established pending development of freshwater sediment quality standards. Future sediment
cleanup levels will likely be similar to sediment quality criteria reviewed by Ecology (1991)
and discussed in previous sections of this chapter. Thus, adoption of freshwater sediment
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cleanup levels may trigger cleanup actions in the Black River basin, because sediment
monitoring results indicate pollutant levels that exceed sediment quality criteria.
The Model Toxics Control Act has also established soil cleanup levels for hazardous waste
sites. These levels apply to sediments disposed of on land other than a permitted landfill (e.g.,
vacant city property). Soil cleanup levels for residential and commercial sites were exceeded
at several monitoring stations. The Naches drain (station 8) had very high TPH and PAH
concentrations that exceeded cleanup levels by more than a factor of 10. The Naches drain
also had the highest lead concentration (246 mg/kg), which approached the soil cleanup level
of 250 mg/kg.
Dangerous waste regulations consist of criteria for designating wastes that must be disposed of
at licensed hazardous waste disposal facilities (e.g., the facility located at Arlington, Oregon).
Although testing procedures specified in the dangerous waste regulations were not carried out
on sediments in this study, toxicity characteristics have been estimated from the available data.
None of the sediments sampled appear to exceed the maximum contaminant level criteria and
therefore probably would not require disposal at a licensed hazardous waste disposal facility.
Criteria are also provided in WAC 173-303 for persistent dangerous wastes that contain
halogenated hydrocarbons or PAHs. The maximum concentration of either group of
contaminants is 0.01 percent (100 mg/kg), which was not exceeded in any sediment sample.
King County issues permits for disposing of contaminated sediments at the Cedar Hills
regional landfill. A permit is issued if the sediment does not exceed dangerous waste criteria
and has a TPH concentration less than 30,000 mg/kg dry weight (Burke 1992 personal
communication). In the absence of toxicity characteristic leaching procedure (TCLP) results,
King County uses sediment quality results in determining acceptability of sediments for landfill
disposal. In making that determination, the county also considers solubility of contaminants.
Because Black River basin sediments have probably been exposed to flowing water conditions
for an extended period, the contaminants in those sediments would probably be considered
insoluble and thus more acceptable (than soluble contaminants) for landfill disposal.
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8. SOURCES OF BASIN PROBLEMS
The types and levels of pollutants in stormwater runoff vary depending on the nature of the
land uses generating the runoff. Construction activity can result in soil erosion and
downstream sedimentation. The character of post-construction runoff from developed sites
depends on a variety of factors such as the amount of paved area onsite that is subject to
vehicular use, the types of chemicals and other materials used onsite, and the methods used to
handle chemicals and other materials. For these reasons, anticipation of future stormwater
quality issues and potential problems requires an understanding of future land use patterns.
LAND USE
Land use conditions in the Black River basin are described by Northwest Hydraulic
Consultants (1991). Present and future land use in the Panther Creek and Springbrook Creek
basins is described in Volume 3, Appendix B, Table 2. Current land use conditions were
defined using aerial photographs of the area from 1988 and 1989. Future land use
representing full development conditions was estimated from area comprehensive plans and
local zoning maps.
Commercial development predominates in the lowland areas in the western portion of the study
area (i.e., Springbrook Creek basin), along the SR-405 and SR-167 corridors, and in the
Renton commercial district (Appendix B, Table 2). Although a large portion of the
Springbrook Creek basin is currently undeveloped (approximately 1,510 acres), most of this
area (approximately 870 acres) is expected to be converted to commercial and high density
residential use under full development conditions. As shown in Appendix B, Figure 3, future
development in the Springbrook Creek basin will convert the existing undeveloped forested
and low density residential areas in the basin to predominantly commercial and high density
residential use.
Most residential development has occurred and will continue to occur in the eastern part of the
study area in the Panther Creek basin. The two primary categories of residential use that
currently exist in the upland areas are high density (710 acres) and low density (391 acres)
development (see Appendix B, Table 1). Under full development, most of the existing low
density residential and remaining undeveloped forested lands will be converted to high density
and multifamily development (see Appendix B, Figure 4).
INDUSTRIAL AND COMMERCIAL DISCHARGE
Industrial and commercial facilities that operate in the Black River study area are potential
sources of pollutants to surface water and ground water in the basin. The primary transport
pathways for the pollutants are stormwater runoff, accidental spills, leaks from equipment and
chemical storage facilities, and direct discharges from permitted facilities (i.e, National
Pollutant Discharge Elimination System [NPDES] or state wastewater discharge permits).
Pollutants that may be associated with industrial activities include oil and petroleum
63
hydrocarbons, total suspended solids, metals, conventional pollutants (e.g., total phosphorus;
biochemical oxygen demand), and solvents and other organic contaminants.
A survey of businesses operating in the basin was conducted to identify potential industrial and
commercial pollutant sources. The following agency files and databases were surveyed to
identify potential sources:
■ City of Renton business license records
■ Field survey of basin
■ Ecology records of NPDES and state wastewater discharge permits
■ Ecology toxic cleanup program site list
■ U.S. EPA Facility Index System (FINDS)
■ U.S. EPA Comprehensive Environmental Response, Compensation, and
Liability Information System (CERCLIS).
This study does not include consideration of future development of industrial and commercial
facilities that would be potential sources of pollutants because of the uncertainties of future
development of specific types of business operations in specific locations within the study area.
Licensed Businesses
In all, there are more than 1,050 licensed businesses within the study area. However, fewer
than 200 of these businesses are considered potential sources because of the nature of their
operations (e.g., manufacturers, vehicle maintenance and repair shops, photographic and
photocopy services, metal finishers and fabricators, laundries, fuel and service stations). Most
industrial and commercial facilities are located within the Renton central business district, in
the valley west of SR-167, or along the I-405 and SR-167 corridors.
Potential industrial and commercial sources were identified based on their standard industrial
classification (SIC) designation. Priority rankings (1 to 3) have been assigned to each facility
based on its potential to discharge pollutants, as summarized below:
High Priority (1)
Manufacturers (e.g., steel, chemicals)
Metal finishers and fabricators
Auto repair shops and junkyards
Medium Priority (2)
General and special trade contractors
Paint retailers
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Warehouse and freight operations
Printers, graphics shops, film developers
Dry cleaners
Low Priority (3)
Retailers and wholesalers
Office and commercial
There are 83 high-priority businesses in the basin, 58 of which are automotive repair or service
stations. Pollutants typically associated with these facilities include petroleum hydrocarbons,
solvents (cleaning and degreasing agents), and metals. The remaining high-priority facilities in
the basin encompass a variety of industrial categories, such as metals fabricators, electronic
equipment manufacturers, chemical manufacturers, and petroleum storage and pipeline
facilities.
Medium-priority businesses number about 92 in the Black River basin, 50 of which are
building and special trade contractors. The 875 remaining businesses are considered to have a
low potential to contaminate streams in the basin. Low-priority businesses consist primarily of
office, retail, and wholesale facilities.
Windshield surveys (i.e., informal observations collected while in a vehicle) of businesses in
the basin were conducted on December 19, 1991 and January 15, 1992 to document existing
industrial practices and to identify specific problems in the basin. The results of the surveys
indicate that poor housekeeping practices, such as improper storage and disposal of waste
materials, constitute a continuing problem that could contaminate soil, surface water, and
ground water in the Black River basin.
City of Renton staff report that washoff of oil and grease from automobile service stations and
dealerships is another common problem. In most cases, implementation of best management
practices (BMPs) would be effective in controlling these pollutant sources. Examples of
appropriate BMPs include restricting use of automotive fluids to paved areas indoors or under
cover, using drip pans or tarps when changing engine fluids, sweeping vehicle repair areas
rather than hosing them down, and training employees in good housekeeping practices and
emergency spill cleanup procedures. Technical assistance is needed, either through trade
organizations (e.g., Association of General Contractors) or state and local agencies, to
familiarize local business operators with accepted management practices. The city could
consider developing an inspection and enforcement program to ensure that BMPs are
implemented.
NPDES-Permitted Facilities
BP Oil Company is the only NPDES-permitted facility in the Black River basin. Under its
permit, this bulk petroleum storage facility is allowed to discharge stormwater runoff from the
loading rack area, drainage from the diked storage areas, and tank-bottom water, to
Springbrook Creek. All discharges from the site pass through an oil/water separator before
release to the creek.
65
Under new NPDES regulations, stormwater runoff from certain industrial facilities and
construction sites larger than 5 acres will also be subject to NPDES permit requirements.
Industrial facilities in the Black River basin that will require NPDES permits for stormwater
discharges include the following:
■ Aim Aviation
■ Commercial Carriers
■ Consolidated Freightways
■ Leaseway Transportation Corporation
■ Manufacturer's Mineral Company
■ Motorways Ltd.
■ Renton Issaquah Auto Freight
■ Renton Sand and Gravel
■ Superior Fast Freight
■ Waste Management of North America.
These facilities were required to file a notice of intent with Ecology for coverage under a
baseline general permit by October 1, 1992. In addition, each facility must develop a
stormwater pollution prevention plan by October 1, 1993 and implement the plan by October
1, 1994.
Contaminated Sites
The following three sites in the basin are included on the Ecology model toxics cleanup
program list of contaminated sites in Washington:
■ BP Oil Company bulk petroleum facility
■ Renton Junction landfill
■ Sternco site.
A brief description of each site is provided in the following sections. No federal Superfund
sites are located in the basin.
BP Oil Company
Soil and ground water beneath the site are contaminated with petroleum products as a result of
a leak in the spill containment system for the loading rack area. The source of the leak was
identified and repaired in 1988. However, ground water remediation operations continue at
the site to recover spilled product. As of May 1992, approximately 50,000 gallons of product
have been recovered (Hart Crowser 1992).
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Renton Junction Landfill
King County operated the Renton Junction landfill, located directly west of the Metro Renton
wastewater treatment plant, from 1946 to 1958. The landfill reportedly received only
municipal refuse. The site is currently rated C2 (potential hazardous substance site) by
Ecology because of potential ground water, surface water, and soil contamination.
Sternco Site
The Sternco site, located at SW 43d Street and Oakesdale Avenue SW, was operated as a scrap
metal salvage and recycling facility from 1967 to 1985 by the Sternoff Metals Corporation.
Transformers were accepted until 1977.
Springbrook Creek flows through the Sternco site. No contamination was found in either
water or sediment samples collected during a recent remedial investigation at locations where
the creek enters and exits the site (Seacor 1991). However, the concentrations of antimony,
arsenic, cadmium, and lead in sediment collected from two drainage ditches that discharge to
Springbrook Creek exceeded soil cleanup levels established by the Model Toxics Control Act.
In addition, arsenic, cadmium, mercury, and TPH in onsite soil exceeded the cleanup levels
(Seacor 1991).
Hazardous Waste Generators
There are 24 large-quantity generators and three licensed transporters of hazardous waste
within the study area. Large-quantity generators are those that accumulate more than 2,200
pounds per month (or per batch) of dangerous wastes or more than 2.2 pounds per month (or
per batch) of extremely hazardous waste. Registration as a generator does not necessarily
indicate that a facility is an active pollutant source. However, handling of large quantities of
hazardous wastes increases the potential for release of these materials in spills or accidents.
Under dangerous waste regulations (WAC 173-303), each large-quantity generator is required
to prepare and implement a contingency plan for responding to emergencies involving
hazardous waste. These plans generally describe procedures for containing the spilled material
to prevent contamination of surface water and ground water supplies.
POTENTIAL HAZARDS AND SPILL CONTAINMENT
Accidental spills from industrial facilities and transportation-related sources represent a
potential threat to surface water and ground water in the Black River basin. Uncontrolled
releases resulting from spills or leaks are often difficult to track because they are not always
reported. Consequently, these releases may not be adequately cleaned up, allowing
contaminant residues remaining in soil or ground water to act as long-term pollutant sources.
The general public often contributes to the problem by improperly disposing of household
wastes. For example, used crankcase oil is often discharged into.,storm sewers, which
eventually discharge to local streams. Although individually these discharges may seem
67
unimportant, the cumulative effect from many individual discharges can significantly degrade
water quality.
Industrial and transportation spills that have been reported in the basin are described in the
following sections.
Industrial Spills
Most spills are reported to Ecology's regional spill response units. Since 1990, spill reports
received by the northwest regional office, which covers the Black River basin, have been
entered on a computer database. (Records of spills for the entire region prior to 1990 are
stored in chronological order in a paper file. Information for many of the earlier spills is
incomplete.) Consequently, this review focuses on the most recent spills for which
information is readily available through the Ecology database.
Seventeen spills occurred in the Black River basin in 1990 and 1991. Eleven of the spills
involved oil and petroleum products. Although quantity information is incomplete, most spills
appear to involve less than 100 gallons of material, with discharges primarily to soil and
roadways. The largest spill (550 gallons of petroleum products) occurred at Olympic Pipeline
Company. Only one of the reported spills directly affected ground water, and three affected
surface water. In addition, three spills involving hazardous materials and two involving
unknown chemicals occurred during the 2-year period.
Metro also receives and investigates water quality complaints. Since 1986, Metro has received
three complaints affecting Springbrook Creek, two of which occurred in 1986. The first
report was of a visible oily sheen on Springbrook Creek between SW Grady Way and
Longacres. No estimates of the quantity or chemical composition of material spilled were
available, and the geographic source was not identified. The second complaint involved
discharge of animal waste to the creek at Lind Avenue SW and SW 27th Street near the
Longacres facility. Finally, in 1989, diesel fuel and paint were observed in a ditch draining to
Springbrook Creek from the Longacres practice track. The source of the diesel fuel was not
identified; however, the paint apparently came from the stables at Longacres, which were
being reroofed. No cleanup was conducted.
New and existing large-quantity generators of hazardous waste are required to prepare and
implement contingency plans for handling spills and accidents involving hazardous waste.
These plans, if properly designed and implemented, should be effective in reducing the
potential for contamination of surface water and ground water.
Smaller industrial and commercial facilities are generally not prepared or equipped to handle
spills and accidents. Although these facilities typically use smaller quantities of chemicals in
their operations, the spill records (Table 12 of Volume 2, Appendix A) indicate that smaller
facilities are responsible for most of the 17 spills reported in the basin between 1990 and 1991.
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Transportation-Related Spills
Five state highways (SR-401, SR-515, SR-167, SR-900, and SR-181) pass through the Black
River basin study area. These highways carry a large volume of truck and automobile traffic.
Storm drains that serve SR-181 discharge to the Green River, and storm drains that serve the
remaining four roadways eventually discharge to either Springbrook Creek or Panther Creek.
Consequently, materials released during an accident (e.g., crankcase oil, transmission fluid, or
chemicals being transported) could contaminate these streams. In particular, SR-167 is located
adjacent to the Panther Creek wetland. This proximity increases the potential for spills from
accidents that may occur along this section of highway to enter the wetland before emergency
response crews can contain the spill.
A total of 7,425 accidents were reported on state highways in the Black River basin study area
during the 7-year period from 1985 to 1991. The majority of the accidents (4,051) occurred
on SR-167. Of the total, 463 accidents involved trucks over 10,000 pounds, and three
accidents involved trucks carrying hazardous materials.
Local fire districts are usually the first to respond to emergency spills. Most fire districts,
including the city fire department, have one hazardous materials team to handle emergency
response. These teams generally assess the spill and are responsible for containing or
stabilizing the material. Local fire departments may request assistance from Ecology in
responding to large spills.
SEDIMENT LOADING
Existing Conditions
The Black River basin is characterized by two distinct physiographic regions. An upland
plateau extends along the eastern portion of the basin and includes the Springbrook Springs,
Panther Creek, and Rolling Hills subbasins. Soils on the plateau consist primarily of
Alderwood gravelly, sandy loams. Much of the upland area is located in the Panther Creek
subbasin. From the western edge of the plateau, the hillside drops fairly steeply to the valley
floor. Soils in the lowland region of the Green River valley floodplain, which includes the
valley and south Renton subbasins, consist primarily of Woodinville and Snohomish series silt
loams.
Soil and stream channel erosion have had a detrimental effect on fish habitat and channel
conveyance capacity in streams throughout the Black River basin. Native soil and topographic
conditions create erosive conditions on the steep slopes along the upland plateau in the eastern
portion of the basin. This naturally occurring erosion has been accelerated by increased
development, particularly in the upper reaches of Springbrook Creek and Panther Creek where
runoff from residential development is discharged to the steep ravines leading from the
plateau. Sediments eroded from the upper basin are then deposited within the stream channels
as these streams reach quiescent conditions in the valley floor, resulting in the choking of fish
spawning gravels and blocking of fish passage. As a result,:many of the streams in the basin
are devoid of fish, and migratory salmonid numbers in the Black River are severely depressed
69
(King County 1987). In addition, sediment deposits have reduced the channel conveyance
capacity and clogged conveyance structures, creating severe flooding hazards in the lower
basin. A brief description of existing problems in Panther Creek and the Springbrook Springs
tributary is provided below.
Panther Creek
Erosion and channel downcutting is evident in the upper 1 to 1.5 miles of Panther Creek,
where the stream gradient is as high as 15 percent. Sediments derived from the upper basin
are depositing in the lower-energy areas, resulting in the formation of a large alluvial fan at the
base of the plateau. Sediments are also filling the Panther Creek wetland and have blocked
fish passage in the lower section of the stream (King County 1987).
Springbrook Springs Tributary
The Springbrook Springs tributary has experienced problems similar to those in Panther Creek.
The upper 0.6 miles of the stream passes through a steep ravine, where the channel gradient
exceeds 15 percent. Runoff from residential development has accelerated natural erosion
processes, causing stream bank erosion and landslide activity. Localized erosion problems
have also occurred at some storm drain outfalls. Sediment deposits in the lower section of the
stream have reached depths of approximately 5 feet (King County 1987). The excessive
sedimentation has resulted in downstream property damage.
Sediment Loading Estimates
Two primary sources contribute to stream sediment loading: soil erosion and stream channel
erosion. Soil erosion is caused in large part by land clearing activities associated with
construction and development. In addition, the accumulation and subsequent washoff of street
dust and litter from impervious surfaces during storm events contributes to the suspended
solids loading in urban streams. Stream channel and gully erosion result from the erosive
action of concentrated runoff. Gullying occurs on open hillsides as previously unconcentrated
sheet runoff becomes concentrated in rills and gullies, forming drainage channels where none
previously existed.
Erosion and sediment transport in stream channels are natural processes that occur as the
stream channel responds to changes in hydrologic and sediment loading conditions. Channel
geometry and bed load transport are usually determined by larger runoff events. Increases in
the peak flow rate and duration caused by urban development can significantly affect channel
stability and increase the amount of sediment transported by the stream. Experience has
shown that landslides and stream bank degradation caused by uncontrolled urban development
can generate a large amount of sediment.
A detailed analysis of sediment loading in the study area is presented in Appendix B of
Volume 3.
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Construction
Soil erosion losses during construction can be controlled to a large extent by natural soil
characteristics and topography and by management practices implemented to stabilize disturbed
soil during construction. Upland soils in the Panther Creek and Rolling Hills subbasins are
highly susceptible to erosion when disturbed. However, with proper erosion control methods,
the effects from construction can be greatly reduced. Erosion losses from exposed, bare soil
range from approximately 0.3 tons per acre to 2.3 tons per acre, depending on site topography
(i.e., 5 to 20 percent slope). If disturbed soils are rapidly restabilized with sod, erosion losses
can be reduced to approximately 0.02 tons per acre. Other management practices such as
reseeding, mulching, and restricting construction to dry weather periods are also effective in
reducing soil erosion.
Approximately 800 acres of undeveloped land remain in the Panther Creek and Rolling Hills
subbasins. With existing water supply and transportation corridor constraints, full
development in this basin may occur within the next 15 to 20 years. Assuming that
development occurs uniformly during this period, annual erosion losses resulting from
construction in the basin are estimated at 100 tons per year without implementation of erosion
control measures, and 1 ton per year with controls (i.e., immediate sodding).
Lowland soils in the Black River basin are generally less susceptible to erosion than are upland
soils in the basin because of the generally level terrain (0.5 to 1 percent slopes) along the
valley floor. Soil erosion losses during construction in the Springbrook Springs, valley, and
south Renton subbasins are estimated at 0.1 to 0.2 tons per acre without site controls and less
than 0.01 tons per acre with immediate resodding.
The remaining 1,575 acres of undeveloped land in the Springbrook Springs, valley, and south
Renton subbasins is expected to be converted to commercial use within the next 5 to 7 years
(Meyer 1992 personal communication). If development occurs at a fairly constant rate, annual
soil erosion losses are estimated at 42 tons per year without erosion control measures and about
0.3 tons per year with controls.
Future Conditions
With future development in the Black River basin, most of the remaining undeveloped land
will be converted to residential, commercial, or industrial use. Total sediment loading is
predicted to decline from the present level of 750 tons per year to about 510 tons per year after
development is complete. This reduction in sediment loading will result primarily from the
reduction in the amount of undeveloped, cleared land (from 458 acres to 152 acres) that
remains after full development. Undeveloped, cleared land is highly susceptible to erosion,
particularly in the Panther Creek subbasin where soils and steep slopes are conducive to
erosion, unless corrective mitigation measures are employed. Once developed, a large portion
of this land will be covered with impervious surfaces and will no longer be susceptible to
erosion.
Washoff of sediments that accumulate on impervious surfaces in the developing basin will also
contribute to sediment loading in the streams in the Black River basin study area. Sources of
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accumulated sediment include tire wear on street surfaces (tire fragments and asphalt), vehicle
undercarriage washoff, abrasion of street surfaces, animal waste, and other organic debris.
Although these sources of sediment loading are predicted to increase from about 320 tons per
year to 400 tons per year as a result of development, the decrease in sediment loading that will
result from reduction in soil erosion in the basin far outweighs the increase from impervious
surface washoff.
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9. AQUATIC RESOURCES OF SPRINGBROOK AND
PANTHER CREEKS
An inventory of potential impacts on aquatic resources was developed for Springbrook Creek
and Panther Creek through field observations. Results of the water quality and sediment
sampling also have been used to identify activities that may affect aquatic resources. Habitat
inventories of Springbrook and Panther creeks are contained in Volume 3, Appendix H.
SPRINGBROOK CREEK
From the Black River pump station upstream to SW 43d Street, Springbrook Creek flows
through the valley bottom at a gradient of less than 1 percent. The combination of low
gradient, channelization, and heavy sediment loading has resulted in a substrate composed
primarily of dark grey, fine, silty sand and black, fine to medium sand. In some reaches,
small pebbles are mixed with grey, medium to coarse sand. Nearer the upstream limit of the
study area in the vicinity of SW 41st Street and Oakesdale Avenue SW, the stream bottom is
underlain with grey clay beneath a covering of black, silty sand.
The streamside corridor primarily supports a mixture of shrubs and grasses, although along
certain segments, landowners have landscaped their property adjacent to the stream banks.
The canopy is restricted in practically all instances, leaving the stream surface open to solar
heating. Areas adjacent to the channel along the lower reach of the creek immediately
upstream of the Black River pump station have been planted recently with trees and shrubs
that, when mature, will provide some shade. However, the plantings are so widely scattered
and the reach itself is so wide and shallow (approximately 20 to 200 feet wide and 2 to 10 feet
deep) that, at base flow, little improvement in water quality can be expected.
PANTHER CREEK
Under existing conditions, the lower segment of Panther Creek leaves the Panther Creek
wetland at its southern end and crosses under SR-167 by way of several culverts. From the
west side of SR-167 to the intersection of East Valley Road and SW 34th Street, Panther Creek
flows through a short open drainage ditch. At SW 34th Street, the creek enters a series of
underground storm drains, where it is carried a distance of about 2,300 feet to daylight at its
confluence with Springbrook Creek. The substrate in the short open portion of the stream
between the wetland and SW 34th Street is composed primarily of silty sand.
Within the Panther Creek wetland, the substrate consists primarily of decomposing organic
material. From the upstream end of the wetland to Talbot Road South, the bottom is
composed principally of sand, small gravel, and some small cobbles, and the channel is
braided as a result of past high-water events. Much of the base flow in this reach appears to
percolate through the loose gravel substrate. The stream channel is not well defined through
this reach at base flows and appears subject to shifting in response to high storm flows. In
addition, a culvert at Talbot Road South completely blocks potential fish passage upstream.
73
Banks along the existing short reach of open channel between the Panther Creek wetland and
SW 34th Street are covered with low shrubs and grasses dominated by the exotic and invasive
Scotchbroom (Leucoptera spartioliella) and reed canary grass (Phalaris arundinacea).
Within the wetland, an understory of reeds, sedges, and rushes is topped by stands of willow
and a broken overstory canopy of cottonwood and big leaf maple. During summer months
some shade is provided by riparian vegetation. The section from the upper end of the wetland
upstream to Talbot Road South supports a fairly dense understory of blackberry (Rubrus spp.)
bushes and other shrubs and an almost complete canopy of deciduous trees.
EVALUATION OF AQUATIC RESOURCES
The suitability of Springbrook Creek as a source of spawning and rearing habitat for
anadromous and resident salmonids has been rated poor based on several important
characteristics (Metro 1990). The present aquatic resource analysis confirms this evaluation.
Substrate composition is not suitable for spawning throughout the study reach. Significant
improvements in riparian vegetation management would be necessary before cover
requirements advantageous to aquatic life forms could be met. Open streams such as
Springbrook Creek provide prime foraging sites for large piscivorous (fish-eating) birds such
as great blue herons. With little available cover, rearing salmonids become susceptible to
heavy losses from predation by herons and other similar predators.
The presence of heavy metals represents a potentially adverse factor for the aquatic resources
of the Black River basin. Any action taken to reduce the presence of these substances in the
aquatic environment will benefit all organisms inhabiting Springbrook Creek.
Under present conditions, the lack of suitable spawning habitat and questionable rearing
capacity due to degraded water quality, especially during warm summer months, result in both
Springbrook Creek and Panther Creek offering little in the way of fish habitat within the study
area. Upstream of Renton, however, Springbrook Creek and its tributaries, Mill Creek and
Garrison Creek, may contain habitat conditions suitable for salmonid spawning and rearing.
In that respect, lower Springbrook Creek serves as an essential link between the Green River
and headwater spawning grounds. This stream should be managed so that it continues to serve
in that vital capacity.
The proposed reestablishment of lower Panther Creek between Springbrook Creek and the
Panther Creek wetland could, if implemented, result in improved conditions for spawning and
rearing salmon. However, this portion of Panther Creek will suffer from conditions similar to
those found in Springbrook Creek, unless a higher channel gradient, good substrate
composition, and improved cover can be integrated into the project. The restoration of this
portion of Panther Creek would involve establishing a higher channel gradient that could result
in cleaner, more suitably sized substrate and improved water quality through better aeration.
The addition of riparian vegetation along this reach would help to reduce solar heating, thereby
lowering water temperatures as well as affording protection from predators. Upstream of the
wetland, summer low flows and the presence of a complete block to upstream movement at
-Talbot Road severely reduce the value of upper. Panther Creek to salmon. However, upper
Panther Creek does provide habitat for resident trout.
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10. WATER QUALITY SUMMARY
Water quality problems identified in the preceding chapters are summarized below for the
following subbasins in the Black River study area: Springbrook Springs, Panther Creek,
Rolling Hills, valley, and south Renton. The following existing and potential problems are
summarized for each subbasin:
■ Base flow water quality
■ Storm flow water quality and pollutant loading
■ Sediment quality
■ Aquatic resources including fisheries
■ Sediment loading
■ Pollutant discharges and spills.
SPRINGBROOK SPRINGS SUBBASIN
Water quality was not monitored in the small Springbrook Springs subbasin. Historical water
quality data indicate that the Springbrook Springs tributary and Panther Creek have similar
water quality. Therefore, water quality problems identified for the Panther Creek subbasin in
the following section are assumed to be similar to those in the Springbrook Springs subbasin.
Sediment quality has not been monitored in the Springbrook Springs or Panther Creek
subbasins. However, field observations have identified a predominance of sand and gravel in
Springbrook Springs tributary and Panther Creek. Based on the findings of low concentrations
of contaminants in sandy sediment from the Rolling Hills drain (which collects runoff from the
most developed subbasin in the eastern plateau), sediment contamination in Springbrook
Springs tributary or Panther Creek is not likely a problem.
Aquatic resources in the Springbrook Springs subbasin have not been surveyed. However, fish
habitat problems associated with the water quality, sedimentation, and culvert crossings
identified for Panther Creek also apply to Springbrook Springs tributary. During a field
review conducted by the Washington Department of Wildlife in late 1992, four salmon redds
(spawning beds) were observed in Springbrook Springs Creek in the reach between SR-167
and the crossing at S. 192d Street west of Talbot Road South. Cutthroat trout are also likely
to use this stream (Schneider 1992 personal communication).
Many of the problems in the Springbrook Springs subbasin are caused by erosion that occurs
along the steep ravine. Although part of the subbasin lies within the Renton public water
supply watershed, stormwater runoff from adjacent development has accelerated naturally
occurring erosion problems in the channel. Medium- and high-density residential use accounts
for most of the development occurring in the subbasin. This trend is expected to continue as
the subbasin reaches fully developed conditions. Implementation of the Renton stormwater
ordinance should help to reduce impacts from future development. However, additional work
may be required to correct problems caused by existing development, to reduce sediment
loading and alleviate associated water quality problems (i.e., elevated turbidity, total
75
suspended solids, and nutrient concentrations). Examples of potential improvements include
retrofitting existing storm drainage systems and repairing unstable stream banks.
PANTHER CREEK SUBBASIN
Base flow water quality problems in Panther Creek include exceedance of criteria for
temperature and fecal coliform bacteria. Storm flow water quality problems include
exceedance of criteria for copper, lead, zinc, and fecal coliform bacteria. Additional storm
flow water quality problems in Panther Creek include high levels of turbidity, suspended
solids, and phosphorus. Storm flow pollutant loadings were high in Panther Creek for
suspended solids, phosphorus, and fecal coliform bacteria. A substantial proportion of the
phosphorus and fecal coliform bacteria were deposited in the Panther Creek wetland, as
evidenced by the loadings that were approximately three times higher in Panther Creek than in
the 34th Street drain.
As noted for the Springbrook Springs tributary, sediment grain size and land use in this
subbasin are not likely to result in sediments that are heavily contaminated in Panther Creek.
The aquatic resources in Panther Creek are impaired by the water quality problems described
above. Low flow in the summer and large deposits of sediment present problems for fish
rearing in Panther Creek. Fish migration is prevented between Springbrook Creek and
Panther Creek because there is no open-water connection. In addition, fish migration is
prevented in Panther Creek at Talbot Road South and possibly at other culvert crossings.
Upper Panther Creek provides habitat for resident trout.
The Panther Creek subbasin exhibits many of the same problems as those found in the
Springbrook Springs subbasin. Stream bank and soil erosion in the upper 1 to 1.5 miles of
Panther Creek account for many of the water quality problems in Panther Creek. Naturally
occurring erosion in the steeply sloped ravine has been accelerated by ongoing development.
High sediment loading contributes to the elevated turbidity and the suspended solids and
nutrient concentrations found in the stream. While erosion is a major problem in the upper
portion of the subbasin (i.e., above Talbot Road South), sediment deposition and associated
problems with stream habitat degradation and reductions in channel conveyance capacity are
the major concerns in the lower portion of the subbasin (i.e., below Talbot Road South). In
addition, there is a greater proportion of commercial development in the lower portion of the
subbasin, which increases the potential for contamination in runoff from these areas.
However, none of the businesses operating in the lower portion of the subbasin (which consist
primarily of general building and trade contractors) are considered a high priority (i.e., a
generator of significant pollutants).
Although there is more commercial development in the Panther Creek subbasin than in the
Springbrook Springs subbasin, future development in the Panther Creek subbasin is expected
to be predominantly residential. Consequently, these two subbasin will likely continue to
experience similar water quality problems associated with increased runoff and associated
sediment loading.
76
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Finally, SR-167 also passes through the lower portion of the subbasin. This highway carries a
large volume of traffic. Numerous accidents have been reported along this route in the last 6
years. Spills of petroleum products and other chemicals that may be transported along this
highway could enter Panther Creek and the adjacent wetland.
ROLLING HILLS SUBBASIN
Base flow water quality problems in the Rolling Hills drain include exceedances of criteria for
temperature and fecal coliform bacteria. Storm flow water quality problems include
exceedances of the criteria for copper, lead, zinc, cadmium, and fecal coliform bacteria.
Storm flow pollutant loadings were very high in the Rolling Hills drain for these contaminants
and suspended solids. The data suggest that only a small proportion of the Rolling Hills
tributary pollutant loadings were deposited in the Panther Creek wetland. The sandy sediment
in the Rolling Hills drain was of acceptable quality.
Aquatic resources in the Rolling Hills subbasin have not been surveyed. Local residents have
reported that there are cutthroat trout in the upper part of the Rolling Hills stream system.
Drainage corridors consist of pipes and ditches that do not provide fish habitat.
A significant portion of the Rolling Hills subbasin is steeply sloping. The greater landslide
and erosion hazards associated with these steep slopes contribute to the high sediment loading
in the drain. The subbasin is also more highly developed than either the Panther Creek or
Springbrook Creek subbasins and is already approaching fully developed conditions.
Commercial and high density residential development comprise approximately 55 percent of
the subbasin. Land use is not expected to change significantly with future development. The
primary change expected is an approximate 25 percent increase (from 106 acres to 133 acres)
in multifamily development (Northwest Hydraulic Consultants 1991).
Higher metals concentrations are often present in stormwater runoff from commercial and
high-density urban development, as well as highway runoff. Runoff from I-405, the Renton
Center, and portions of the Renton commercial district likely contribute to the metals loading
in this drain. In the last 2 years, one spill involving 50 to 100 gallons of petroleum product
was reported in the ditch at the intersection of I-405 and SR-167. In addition, several high-
priority businesses (i.e., auto repair facilities) are located in the subbasin. Depending on the
housekeeping practices implemented, these facilities can often be sources of metals and
petroleum hydrocarbons. Other, lower-priority businesses located in the subbasin that are also
considered potential sources of contamination include dry cleaning establishments and motor
freight warehouses.
VALLEY SUBBASIN
Base flow water quality problems in Springbrook Creek include exceedance of criteria for
temperature, dissolved oxygen, zinc, and fecal coliform bacteria. Primary sources of the base
flow water quality problems in Springbrook Creek originate upstream of the study area.
However, decomposition of organic matter in the valley-subbasin likely exacerbates the
dissolved oxygen problem. Although water quality criteria were frequently exceeded in drains
77
that discharge to Springbrook Creek, these sources contribute relatively low hydraulic and
pollutant loadings during base flow conditions.
Storm flow water quality problems in Springbrook Creek include exceedance of criteria for
turbidity, copper, lead, zinc, cadmium, and fecal coliform bacteria. Additional storm flow
water quality problems include high suspended solids and total phosphorus concentrations.
Similar water quality problems were observed in the 34th and 19th street drains. Water
quality criteria were exceeded most often in the Kent drain but were rarely exceeded in the P-9
channel. Loadings of suspended solids, copper, and zinc were highest in the Kent drain. The
34th Street drain and P-9 channel had relatively low pollutant loadings. Other possible sources
of water quality problems include two streams draining Longacres.
Sediment quality problems in Springbrook Creek include exceedance of lowest effects criteria
for total organic carbon and all metals tested. These problems were observed at the four
locations exhibiting fine-grained sediment but not at the single location (SW 16th Street j
bridge) where coarse-grained sediment was present. Severe effects criteria were exceeded for
cadmium upstream of SW 43d Street and for total organic carbon downstream of the P-9
channel. Low effects criteria were also exceeded for pesticides and PCBs at the mouth of
Springbrook Creek. In addition, TPH concentrations at all locations in Springbrook Creek
except at SW 16th Street exceeded soil cleanup levels, thus restricting disposal of these
sediments, if dredged, to an approved landfill.
The water and sediment quality problems described above result in poor habitat for the aquatic
resources of Springbrook Creek. A lack of riparian cover contributes to the temperature
problem and makes fish susceptible to predation by great blue herons and other predators.
Lower Springbrook Creek serves as an essential link to Garrison Creek for a small population
of returning salmon (approximately 100 per year).
The valley subbasin consists almost exclusively of commercial and light industrial land use.
With future development, the remaining vacant land in the subbasin is expected to be
converted to commercial and industrial use. Runoff from these areas and from SR-167, which
passes through the valley subbasin, can contribute high metals loading to Springbrook Creek.
In addition, numerous existing businesses, which due to the nature of their operations are
considered potential contaminant sources (e.g., auto repair facilities, auto wrecking yards, a
bulk petroleum storage plant, and avionics facilities), have been identified in the subbasin.
A number of large-quantity generators of hazardous waste operate in the valley subbasin.
Designation as a generator does not necessarily indicate that these facilities are contaminant
sources. However, because their operations involve handling large quantities of hazardous
materials, these facilities are considered potential contaminant sources and have been given a a
high-priority ranking.
Several problems associated with improper storage and disposal of waste materials were
identified at businesses located in the valley subbasin during a recent windshield survey of the
area. In addition, several spills have been reported in this subbasin. Most spills have involved
small quantities (less than 100 gallons) of primarily petroleum products. However, several
small spills of unknown chemicals or hazardous materials have been reported in the valley
78
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subbasin. These and other unreported incidents represent a continuing threat to water quality in
Springbrook Creek.
Two contaminated sites have also been identified in the valley subbasin: the Sternco site and
the BP Oil Company facility. The Sternco site may be a source of metals to Springbrook
Creek. Elevated concentrations of cadmium, chromium, copper, lead, nickel, and zinc have
been observed in onsite soil, drainage ditches, and adjacent wetlands. The BP Oil Company
facility is currently undergoing ground water remediation to recover oil that leaked from an
underground sump. This site is also located adjacent to Springbrook Creek. Consequently,
oil-contaminated ground water may affect water quality in the creek.
One of the largest known sources of contamination to the valley section of Springbrook Creek,
the Western Processing Superfund site, is located outside the study area. This site is currently
undergoing cleanup. Contaminants associated with the Western Processing facility include
cadmium, copper, nickel, zinc, and chlorinated volatile organic compounds such as
trichloroethylene.
In addition, although erosion potential in the valley subbasin is relatively low due to the level
terrain, this section of Springbrook Creek experiences erosion-related problems caused by
upstream sources. Much of the material eroded in the Springbrook Springs and Panther Creek
subbasins is deposited along the stream channel in the flat valley floor. These sediment
deposits have reduced the conveyance capacity of the channel, damaged fish habitat, and
clogged conveyance structures, increasing flood hazards in this portion of the study area.
SOUTH RENTON SUBBASIN
Base flow water quality problems in the Black River include exceedance of criteria for
temperature, dissolved oxygen, copper, lead, zinc, and fecal coliform bacteria. Metal
concentrations were observed to increase and fecal coliform bacteria levels were observed to
decrease in waters passing through the Black River pump station forebay. The Naches Avenue
drain did not affect base flow water quality in the Black River.
Storm flow water quality problems in the Black River include exceedance of criteria for
turbidity, copper, zinc, and fecal coliform bacteria. Suspended solids and total phosphorus
concentrations were observed to decrease in waters passing through the forebay. Similar storm
flow water quality problems were observed in the Naches Avenue drain. Pollutant loadings in
the Naches Avenue drain were average compared to other drains in the study area.
Sediment quality problems in the Black River and the Naches Avenue drain include exceedance
of lowest effects criteria for total organic carbon and all tested metals except mercury. In
addition, criteria for some PAHs and pesticides were exceeded in the Naches Avenue drain.
Concentrations of TPH and lead were much higher in sediment from the Naches Avenue drain
than in any other sediment sample. Disposal of dredged sediment from the Black River and
the Naches Avenue drain would be restricted to an approved landfill.
As identified for Springbrook Creek, the water and sediment quality problems identified in the
Black River result in poor habitat for aquatic plants and animals.
79
The south Renton subbasin lies almost entirely in the Renton commercial district. Because of
the commercial and industrial development in this subbasin, a variety of potential sources
could contribute to the contaminant levels found in the Black River. Although few
documented contaminant sources have been identified, a large number of potential sources are
located in the subbasin, including auto repair operations, metal fabricators, dry cleaning
establishments, and chemical distributors.
Many of the large-quantity generators of hazardous waste that operate in the Black River basin
are also located in the south Renton subbasin. Designation as a generator does not necessarily
indicate that these facilities are contaminant sources. However, because their operations
involve handling large quantities of hazardous materials, these facilities are considered
potential sources and have been given a high-priority ranking.
80
11. WETLANDS ASSESSMENT
Thirty-eight wetlands located within the study area are shown in Figure 7 and described in
Volume 3, Appendix F. Because the wetland numbering system used in the figure is based on
a larger inventory, the numbers are not consecutive.
BENEFICIAL IMPACTS ON WATER QUALITY AND QUANTITY
Wetlands may benefit water quality in several ways. Wetlands may store and slowly release
stormwater, thereby attenuating storm runoff peaks. Wetlands may be hydrologically
connected to ground water and streams and may contribute water to streams during dry
weather months. Overall, the effect of wetlands on surface water quantity is typically to
reduce the seasonal variations in flow. Many of the wetlands along Springbrook Creek act as
sites of both recharge and discharge. During periods of high water flow, the wetlands store
overbank flows and recharge local ground water. During periods of low flow, the wetlands
discharge to Springbrook and Panther creeks, helping to maintain their flows.
Wetlands may purify water by allowing sediments and their adsorbed pollutants to settle out of
the water column. Chemical and biological processes can also remove pollutants from the
water column. Wetlands with denser vegetation and longer residence times for water generally
are more efficient removers of pollutants. Lower phosphorus levels found downstream of the
Panther Creek wetland, compared to levels measured upstream of the wetland, indicate that
this wetland removes nutrients from incoming streams.
MITIGATION AND ENHANCEMENT STRATEGIES
The city of Renton has established goals for wetland preservation through passage of Wetland
Management Ordinance 4346. This ordinance calls for no net loss of wetlands or wetland
functions and values. Additional goals established by the Development Planning Division
include improving stormwater control, flood storage, and water quality; creating wildlife
corridors; increasing aquifer recharge; and consolidating wetland mitigation within the Green
River valley to enhance wildlife habitat and hydrologic value.
Federal regulations .and policies have defined avoidance of impacts as preferred over
compensatory mitigation of adverse impacts on wetlands. If wetland impacts are unavoidable,
compensatory mitigation is typically required. A 1990 memorandum of agreement between
the U.S. Army Corps of Engineers and the U.S. EPA set forth onsite mitigation as the
compensatory mitigation. Other types of mitigation addressed in the agreement include offsite
mitigation within the same watershed and mitigation banking. Two other approaches to
mitigation are fee-in-lieu programs and special-areas management plans. The various
approaches to wetland mitigation are summarized below and described in greater detail in
Volume 3, Appendix G.
Onsite mitigation is accomplished through creation or restoration of wetlands on or adjacent to
a project site. Onsite mitigation has the advantage of replacing wetland functions and values in
81
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Black River Basin Water Quality Management Plan
Figure 7. Wetlands
82
the area where they are lost. However, this method may result in scattered wetland projects
with questionable wetland functions and values. Nonetheless, onsite mitigation will continue
to play an important role in achieving the city's goal of no-net-loss of wetlands.
Offsite mitigation is typically provided on a site apart from the project site but within the same
watershed. This mitigation method offers options and flexibility in meeting some of the city's
wetland goals. Offsite mitigation can be used to restore lost or degraded wetlands of historic
importance, and mitigation requirements from several projects can be pooled to increase
regional wetland areas. Disadvantages of offsite mitigation include the loss of wetland acreage
at the project site, resulting in a localized net loss of wetland function. Species with restricted
ranges may be unable to migrate to newly created or restored wetlands, resulting in an overall
decrease in species diversity.
Mitigation banking involves creating or restoring wetlands in advance of the need for
mitigation. The completed wetland project is then evaluated as a credit against future wetland
losses. Mitigation banking can consolidate mitigation for several small, scattered losses and
thereby provide a larger, more valuable and successful wetland. On the other hand, designing
appropriate functions and values to mitigate unknown future impacts is difficult, and the cost
and time in administration may be prohibitive.
A fee-in-lieu program, in which the developer pays a fee in place of providing wetland
mitigation, has the advantages of simplicity and the possibility of consolidating mitigation
requirements from several projects into larger mitigation programs. The primary disadvantage
of a fee-in-lieu program is that mitigation is not provided concurrently with the impacts. A
fee-in-lieu program is dependent on development to produce the funds for compensation
projects. For this reason, Ecology does not accept fee-in-lieu programs as appropriate
compensatory mitigation.
A special-areas management plan is developed through a federally sponsored interjurisdictional
program for advance planning to protect aquatic resources and wetlands. The plan identifies
potential areas for development and outlines predetermined mitigation for wetland losses. A
regional permit to fill designated wetlands may be issued by the U.S. Army Corps of
Engineers as part of the process. The program is effective in establishing regional strategies
for managing aquatic resources and in fostering advance comprehensive planning of wetland
resources. On a project-specific basis, however, the comprehensive planning approach may
lack sufficient specificity to be very useful. In addition, reaching agreement among all the
parties involved may be difficult. Moreover, the range of federal, state, and city policies and
regulations affecting wetlands, coupled with existing basin planning efforts such as the
ESGRW Plan, may rule out the special-areas management plan as a feasible, cost-effective
mechanism for protection of wetlands in the Black River basin.
Where wetland impacts are unavoidable, onsite and offsite mitigation along with mitigation
banking appear to be suitable alternatives for achieving the goal of no-net-loss of wetland
acreage, values, and functions. Mitigation banking has the potential to meet the city's goals of
consolidating wetlands within the Green River valley for wildlife and hydrologic support,
increasing stormwater control and flood storage, and enhancing water quality.
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The city has initiated a wetland mitigation bank capital improvement project in the Green
River valley on two city-owned properties totaling 45 acres. Approximately 19 acres of
upland areas on these properties have the potential to be excavated and planted to create new
wetlands. These wetlands would be used as a bank to allow other lower-value wetlands, which
have established themselves on top of glacier till fill within the last 15 years, to be filled, up to
a total of 0.99 acres per property. The wetlands that might be filled are analogous to Class IV
wetlands on the Ecology classification table and have limited habitat value. The mitigation
bank sites have existing high quality wetlands with high quality habitat.
The upland areas on the bank sites are adjacent to these high quality wetlands, and wetland
scientists believe that new wetlands could be established that would augment the existing
habitat and wetland areas. In addition, this wetland bank project would add habitat areas
adjacent to nearby wetlands already owned by the city, thus creating a large block of
contiguous habitat, in replacement for scattered, low quality habitat areas.
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12. FISHERIES ASSESSMENT
Metro (1990) reports that the suitability of Springbrook Creek for salmonids is poor. While
coho salmon are known to return to the system, Garrison Creek may provide spawning and
rearing areas, since the conditions in Springbrook and Mill creeks are unsuitable. The
Washington Department of Wildlife, which is responsible for steelhead and cutthroat trout,
was unable to provide any data on fish use in Springbrook Creek (Cropp 1992 personal
communication). Ecolcgy was also contacted but had no information (Penhale 1992 personal
communication). However, steelhead and cutthroat trout have been reported to use this system
(Krom 1990 personal communication).
During the past 7 years, a fish counting device at the Black River pump station has recorded
the following numbers of fish (e.g., salmonids) moving upstream from September through
January (Allmendinger 1990, 1992 personal communications):
1983-1984: 155 1986-1987: 82 1989-1990: 77
1984-1985: 119 1987-1988: 166 1990-1991: 69
1985-1986: 47 1988-1989: 95 1991-1992: 107
While salmonid returns do not appear to be declining, the numbers are extremely low for a
basin the size of the Black River.
85
13. APPLICABLE REGULATIONS AND BASIN MANAGEMENT
Successful reduction of nonpoint pollution depends upon the effective implementation of
management practices by public agencies. Applicable regulations and management practices
are presented in detail in Volume 3, Appendix L, and summarized below.
SURFACE WATER MANAGEMENT
The following federal and state regulatory programs affect surface water management:
■ The National Pollutant Discharge Elimination System (NPDES) requires
several categories of stormwater dischargers to reduce the impacts
associated with their discharges. The requirements apply to industrial
discharges and cities over 100,000 in population. The program in
Washington is administered by Ecology. Ecology recently issued a
baseline general permit that applies to stormwater discharges from
industries and construction sites. This general permit requires
dischargers to prepare individual pollution control plans that incorporate
best management practices (BMPs).
■ The Water Pollution Control Act (RCW 90.48) governs discharges into
surface waters through issuance of a waste disposal permit. All solid
and liquid industrial and commercial waste is regulated. Under RCW
90.48, the state has adopted water quality standards for surface waters
(WAC 173-201).
■ Ecology's Stormwater Management Manual for the Puget Sound Basin
(the technical manual), released in August 1992, establishes guidelines
for stormwater management that local jurisdictions must meet. In many
respects, the guidelines are similar or identical to King County
standards. However, some standards are more stringent (e.g., the water
quality design storm), whereas others are less stringent (e.g., flexibility
allowed in the design of treatment facilities).
■ The U.S. Soil Conservation Service works with farmers to develop
procedures and practices enabling them to meet state water quality
standards. Ecology enforces these plans.
Local jurisdictions require new developments to include effective stormwater detention and
treatment systems both during and after construction. Renton and Tukwila standards for these
systems are similar to those of King County. Kent currently follows the pre-1990 King
County design manual. With Ecology's new technical manual in effect, standards of all four
local jurisdictions will probably converge and be quite similar in the near future. As research
on the effectiveness of stormwater facilities continues, standards are likely to be amended in
the future. Two issues relating to the effectiveness of current management practices are of
immediate concern:
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1. Detention facilities designed for the 24-hour duration storm, based on
present methods of calculating predevelopment release rates, are
consistently undersized. Research conducted by King County suggests
that a 7-day duration design storm and reduced predevelopment release
rates are more appropriate bases for the design of detention facilities
(Ecology 1992b).
2. Improved inspection and maintenance of stormwater management
facilities is needed. Inadequate funding and lack of clear responsibility
for the maintenance of private facilities are frequently cited problems.
Overall, despite the need for improved design standards, management of the design and
installation of stormwater facilities is more effective than post-installation management. Each
jurisdiction could undertake to identify developed areas lacking adequate storm drainage
control and develop a program for correcting identified deficiencies.
FLOOD CONTROL
The National Flood Insurance Act of 1968 and the Flood Disaster Protection Act of 1973
provide the statutory authority for the National Flood Insurance program administered by the
Federal Emergency Management Agency (FEMA). Washington state, under RCW 86.16,
requires local jurisdictions to adopt floodplain regulations that meet or exceed federal
requirements, to be eligible for insurance coverage under FEMA. Ecology reviews and
approves local regulations. The state Shoreline Management Act requires that local
jurisdictions prepare shoreline programs to regulate development along designated shorelines.
Areas subject to flooding along major drainageways may fall under the jurisdiction of the local
shoreline program. The state Growth Management Act requires that each local jurisdiction
designate "frequently flooded areas" as critical areas subject to development controls.
The King County Sensitive Areas Ordinance requires that new structures be floodproofed and
that new development not reduce the base flood storage volume of the floodplain. Kent,
Renton, and Tukwila each have floodplain regulations requiring new structures to be
floodproofed and controlling reductions in flood storage capacity. Kent prohibits new
development in designated floodways but allows some reduction in flood storage capacity,
requiring new developments in the flood fringe to mitigate 50 percent of any loss in flood
storage.
FEMA has prepared flood insurance rate maps for King County that delineate 100'year
floodplain boundaries in the Black River basin. These maps are used by local jurisdictions to
determine whether a proposed development is subject to floodplain regulations. Floodplain
regulations are applied at the building permit or site plan review stage of development
proposals. The regulations are sufficiently defined and unambiguous, so that management of
development in floodplains within the Black River basin is generally effective.
The most recent FEMA study of the Black River basin was.completed:in 1989. This study
includes the development of floodplain maps and base floodwater surface elevations for
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Springbrook Creek and Rolling Hills Creek. More recently, a preliminary hydrologic and
hydraulic analysis, conducted as a part of the ESGRW Plan, indicates that the base flood
elevations of Springbrook Creek may be lower than those determined by FEMA.
The preliminary ESGRW Plan analysis includes a more sophisticated approach to hydrologic
and hydraulic analysis than the method used in the FEMA work. The ESGRW Plan analysis
uses two computer programs, the U.S. EPA Hydrologic Simulation Program—Fortran (HSPF)
(U.S. EPA 1988a) for examining hydrology, and the FEQ (full equations) (Franz 1991) non-
steady state hydraulic computer model for examining hydraulics.
The preliminary ESGRW Plan analysis predicts base flood elevations lower than FEMA for
several reasons, which are described in detail in the Boeing CSTC Facility Floodplain Analysis
Review (R.W. Beck and Associates 1992). Briefly, these reasons include:
■ Improvements made to the Springbrook Creek conveyance capacity,
including increased pumping capacity at the Black River pump station
and improvements to the Grady Way culvert crossing
■ More sophisticated methodology, which for example more directly
accounts for large volumes of flood storage in the valley wetlands and
resulting flood flow attenuation
■ Apparent errors in the topographic information used by FEMA for
determining the bottom profile of Springbrook Creek.
The ESGRW Plan hydrologic and hydraulic analysis is referred to as preliminary because the
analysis needs to be updated to include the recent major floods of 1989 through 1991. Major
floods (including the January 9, 1990 flood, which was the largest flood in the 30 years of
historical record) will affect the determination of the base (100-year) flood elevations. The
base flood elevations are anticipated to increase when these major floods are considered. If,
after considering the recent major floods, the ESGRW Plan predicts Springbrook Creek base
flood elevations to be significantly lower than those of FEMA, the city may wish to consider
amending the regulated FEMA elevation by conducting a formal floodplain revision request.
If the FEMA elevations are amended, it will be important to consider future development in
the basin. Hydrology for determining FEMA floodplains is usually based upon the land use
conditions at the time of a FEMA study. However, for Springbrook Creek, the preliminary
ESGRW Plan analysis shows that there will be a significant increase in flood flows and
corresponding water surface elevations under full development conditions. Therefore, it is
recommended that future hydrologic conditions be used in amending the FEMA base flood
elevations.
GROUND WATER PROTECTION AND MANAGEMENT
The Water Pollution Control Act (RCW 90.48),. regulates the disposal of industrial and
commercial liquid and solid waste into ground water. All such dischargers are required to
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obtain a waste disposal permit. The statute also provides the authority for local health
departments or the state to require disposal permits .for onsite septic systems. Under the
authority of RCW 90.48, the state has adopted water quality standards for ground water.
A wide variety of other federal and state regulations, through their control of specific uses or
activities, also protect ground water. The various federal and state hazardous waste
regulations, for example, contribute to ground water management. The Washington Pesticide
Control Act regulates pesticide application and disposal, and the state minimum functional
standards for solid waste handling include design standards for landfills to protect ground
water.
The Seattle/King County Health Department regulates onsite sewage disposal systems, thereby
contributing to management of ground water quality. Renton has established a protection area
for the Cedar River aquifer, but this area lies outside the Black River basin. Local land use
policies and regulations, which determine the location and extent of impervious surfaces and
therefore influence local ground water recharge, have a significant effect on ground water.
Apart from onsite sewage disposal, which is regulated by King County, local jurisdictions have
not significantly managed ground water within the Black River basin. The Seattle/King
County Health Department is currently engaged in a ground water management program,
which will provide data on ground water quality in King County. Preparation of a plan is
underway to protect ground water in an area that includes the city of Kent as well as areas to
the west, east, and south.
The effects that various widespread activities have on ground water quality are largely
unknown. Many activities are likely to affect ground water and should be studied. For
example, the U.S. Soil Conservation Service and the Seattle/King County Health Department
have developed a joint issue paper (Fitch and Rolla 1991), discussing the effects of pesticides
and fertilizers on ground water quality. Their preliminary conclusion indicates that ground
water quality in King County has not been sufficiently examined to determine if there has been
an effect from the widespread application of pesticides and fertilizers in commercial and
household agriculture and in roadway maintenance.
An ongoing, broad-based ground water monitoring plan could be implemented to identify
whether degradation of ground water quality is occurring. Monitoring results together with
identification of recharge areas would allow identification of possible sources of contaminants.
Education and, if necessary, regulatory programs could then target those potential sources of
contamination.
SOLID WASTE DISPOSAL
The primary source of federal regulation of solid waste is the Resource Conservation and
Recovery Act. This legislation and its implementing guidelines require states to adopt
comprehensive solid waste management programs that meet certain broad criteria.
The state regulates the disposal of solid waste, including dangerous waste, through the Solid
Waste Management Act and the Hazardous Waste Management Act and their implementing
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regulations, the minimum functional standards and the dangerous waste regulations. These
regulations, administered by Ecology, control the disposal of solid waste, including the design
of some solid waste facilities. The minimum functional standards are being expanded to cover
a wider range of solid waste facilities.
King County is responsible for the disposal of solid waste in the Black River basin, except for
the disposal of some hazardous wastes, which may be handled completely by private entities.
The county has adopted a comprehensive solid waste management plan to meet the
requirements of state and federal regulations.
Ecology administers the regulation of dangerous wastes, and the effectiveness of its regulation
largely depends upon accurate reporting and appropriate handling by the large number of
generators. Generators are responsible for meeting Ecology reporting requirements and for
determining if the waste they generate is regulated hazardous waste. Facilities that treat, store,
and dispose of hazardous waste must receive a dangerous waste permit from Ecology.
Municipal solid waste is collected by private haulers and delivered to county transfer stations
for disposal by the county at the Cedar Hills landfill. The county is currently making
arrangements with two private vendors, Rabanco and Waste Management of North America,
for disposal of demolition waste. Both vendors will dispose of these wastes outside the
county. The county is also engaged in a program to provide disposal services to businesses
and households for small-quantity hazardous wastes. Facilities for handling these moderate
risk wastes are being developed at various county transfer stations. These steps should
facilitate the disposal of moderate-risk waste, particularly waste that is handled outside homes
and businesses (such as used automotive oil).
EMERGENCY SPILL RESPONSE
State legislation to prevent or clean up spills of oil and hazardous substances includes the
Hazardous Waste Management Act (RCW 70.105), the Oil Spill Prevention Act, and Oil and
Hazardous Substance Spill Prevention and Response (RCW 90.56). Regulations adopted to
implement this legislation include the dangerous waste regulations (WAC 173-303), the Model
Toxics Control Act cleanup regulation (WAC 173-340), and facility contingency plan and
response contractor standards (WAC 173-181).
Local jurisdictions have adopted the Uniform Fire Code, which contains standards relating to
the storage and handling of flammable substances.
Most fire districts, including the city's, have a hazardous materials van and team, typically one
team per district. Districts lacking hazardous materials capabilities (e.g., King County Fire
District 20) call upon the nearest fire district having the necessary capability. Fire districts
inspect businesses once every year or two for compliance with the Uniform Fire Code.
Generally, emergency spill response is initially handled by the local fire district. Fire
personnel assess the spill and attempt to contain or stabilize it. In addition to reporting spills
to Ecology, fire districts may call Ecology personnel to aid in responding to large spills.
Remediation is carried out by non-agency personnel.
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ONSITE WASTEWATER DISPOSAL
The Water Pollution Control Act (RCW 90.48) governs the disposal of industrial and
commercial liquid and solid waste into ground water. All such dischargers are required to
obtain a waste disposal permit. Under the authority of RCW 90.48, the state has adopted
water quality standards for ground water (WAC 173-200) and has adopted onsite disposal
system regulations (WAC 246-272). The state is responsible for issuing permits for onsite
systems receiving 3,500 or more gallons per day. Local health departments issue permits for
smaller onsite systems. RCW 90.48 provides the authority for local health departments or the
state to require disposal permits for onsite septic systems.
Control of individual onsite disposal systems receiving less than 3,500 gallons per day rests
with the Seattle/King County Health Department. The health department operates under King
County Board of Health Title 13. New residential or nonresidential development projects in
the county may use onsite disposal systems if no sewer hookup is available within a specified
distance and required soil and density criteria are met.
Existing design criteria for septic systems, which reflect recent gains in understanding of long-
term septic system performance, appear to be adequate to protect ground water. The county
reviews designs for new systems and inspects each completed system.
Many older septic systems were constructed under design criteria less stringent than those
existing today. Particularly where older systems were constructed in coarse-grained soils,
treatment efficiency may be low and the associated risk of ground water contamination may be
high. At present, the health department has no regular program of monitoring existing septic
systems.
The county health department could determine whether any of the relatively small areas of
excessively drained soils in the Black River basin contain significant numbers of older septic
systems. If such areas with older septic systems are found, the health department could
monitor ground water quality in those areas for contaminants of concern including nitrate,
fecal coliform bacteria, and volatile organic compounds.
DRINKING WATER MANAGEMENT
Laws and regulations affecting ground water, described above in the section on ground water,
also affect domestic ground water supplies.
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A water right permit is required from Ecology before more than 5,000 gallons per day is
withdrawn from surface waters or ground waters. Aside from exceptional cases, development
of wells for single-family residences does not require a water right permit. The state also
regulates the development of dams, reservoirs, and other public water supply facilities.
Ecology grants approval authority for public water supply facilities to some local health
departments.
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Regulation of drinking water rests largely with the Seattle/King County Health Department.
Drinking water regulations are contained in King County Board of Health Title 12. Renton
has adopted an aquifer protection ordinance, but its area of coverage does not extend to the
Black River basin.
Management of the resources (surface waters and ground waters) used for drinking water are
discussed in other sections.
FISHERIES AND WILDLIFE PROTECTION
Discharge of dredged and fill material into waters of the United States (including rivers,
streams, and wetlands) requires a Clean Water Act section 404 permit from the U.S. Army
Corps of Engineers. A Rivers and Harbors Appropriations Act section 10 permit, also from
the Corps, is required for work in navigable waters.
Any work that changes the flow or occurs in the bed of any freshwater body in the state
(including rivers, streams, and some wetlands) requires a hydraulic project approval from the
state Department of Fisheries. Other state regulations, such as those affecting water quality,
also affect fisheries and wildlife habitat.
King County, Kent, Renton, and Tukwila each either has adopted or shortly will adopt
ordinances governing critical areas and sensitive areas to meet the requirements of the state
Growth Management Act. These ordinances regulate development in geologic hazard areas,
floodplains, wetlands, and streams and rivers. Regulation focuses on preservation of these
areas, to provide protection for fisheries and wildlife. Various zoning regulations that require
landscaping, tree retention, or maintenance of buffer zones in developments also are beneficial
for wildlife habitat. Local regulations are implemented either during environmental and/or
land use permit application review, or during building or grading permit review.
Federal and state regulations and management programs are generally effective in preventing
major losses of fisheries and wildlife habitat designated as critical. Regulations at the county
and city levels are in the process of revision for consistency with the state Growth
Management Act, and it is too early to assess the effectiveness of these changes. Local
regulations are anticipated to be effective in preventing major losses to fisheries and wildlife
habitat designated as critical or sensitive. Regulations at all levels generally do not provide a
significant level of protection for wildlife habitat not designated as critical. In addition,
activities occurring outside designated critical areas can result in degradation of fisheries and
wildlife habitat within the critical areas.
Development proposals in sensitive areas typically require approval from several agencies.
Increased communication among permitting agencies would provide better consistency of
review for these permits. In addition, better enforcement would help to prevent accidental,
incidental, or illicit losses of habitat outside of the permit process.
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AIR QUALITY
Local jurisdictions do not directly regulate regional air quality. However, local environmental
and land use regulations influence the type, location, and nature of new development and
establish project-related mitigation measures, and so have a major indirect effect on air quality
preservation.
The federal Clean Air Act is the primary federal authority governing air quality. Under that
authority, the U.S. EPA has established national ambient air quality standards. States are
required to implement the federal standards. RCW 43.21A and 70.94 provide statutory
authority within Washington for the regulation of air quality. Ecology has established state
ambient air quality standards that are similar to the national standards. The Puget Sound Air
Pollution Control Agency (PSAPCA) was established to implement national and state air
quality standards within King, Kitsap, Pierce, and Snohomish counties. PSAPCA has also
established ambient air quality standards that apply within its jurisdiction. These standards are
similar to the state and federal standards. PSAPCA and Ecology monitor ambient air
conditions at 35 locations within PSAPCA's geographical area of jurisdiction.
Ecology and PSAPCA issue permits for all new major air contaminant sources through new
source construction approvals and prevention of significant deterioration (PSD) permits. In
addition, Ecology regulates individual vehicle emissions in metropolitan areas. During periods
of poor ambient air quality, PSAPCA may apply additional regulatory measures, such as bans
on open burning. Air emissions generally have limited impacts on water quality.
Management of air emissions within existing guidelines appears to be generally effective.
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14. CAPITAL IMPROVEMENT PROJECTS
Recently completed projects include the I-405/P-1 channel box culvert and the I-405/Renton
Village 132-inch culvert just east of the I-405/SR 167 interchange. Both of these projects are
intended to reduce flooding by improving flow capacity at the two locations.
Existing programs and projects include the following:
■ Mosquito abatement in the Panther Creek wetland
■ Improvements to the P-9 channel
■ Planting along the P-1 channel to improve wildlife habitat
■ Tightlining of flows along the Springbrook Springs tributary to reduce
erosion in the tributary channel
■ Wetland mitigation bank in the Green River valley.
Future programmed but unfunded projects include the following:
■ Removal of the sediment deposits from the P-1 forebay to maintain the
storage capacity of the P-1 pond
■ Upgrading of the storm system along SW 7th Street
■ Development of the P-1 channel between SW Grady Way and SW 16th
Street
■ Acquisition of several wetlands associated with Springbrook Creek and
the P-9 channel
■ ESGRW Plan regional flood control alternative(s).
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15. PROBLEM DEFINITION
Table 9 lists known and suspected problems related to water quality within the study area. The
definition of problems began with a preliminary assessment of problems in the basin, presented
in Volume 3, Appendix I. Listed problems were confirmed and defined more specifically
through water and sediment sampling completed during this study as well as during previous
studies. In addition, problems were defined from field observations within the study area and
from conversations with city personnel.
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Table 9. Identified problems in Black River basin study area
HABITAT AND
PROBLEM SEDIMENT WATER QUALITY - WATER QUALITY - WATER QUALITY - WATER QUALITY - OTHER PHYSICAL
DEFINITION QUALITY METALS FECALS NUTRIENTS OTHER PROBLEMS
SPRINGBROOK Unknown Unknown,probably high Unknown,probably high Unknown,probably Unknown,probably high Stream bank erosion in
SPRINGS (not in storm flow in base and storm flow elevated levels turbidity and suspended upper 0.6 mile where
sampled in this study) sediments in storm flows channel gradient is steep
results in sedimentation
in valley floor;Sediment
damage to trout farm
reported during storm
events;Culverts create
barrier to fish at Talbot
Road.and perhaps at
Hwy 167
PANTHER CREEK No problems observed High in storm flow; High in base and storm High total phosphorus in High temperature in base Streambank erosion
Major source is runoff flow;High base flow storm flow likely caused flow caused by lack of problems reported in
from paved surfaces levels possibly due to in part by heavy sediment vegetative cover,High upper 1.4 to 2.6 miles;
malfunctioning onsite load(from construction turbidity and suspended Sediment deposition in
wastewater systems, sites),residential fertilizer solids in storm flows valley floor is damaging
illicit connections and/or use,animal waste,and likely caused by instream Panther Creek wetland;
leaking sewer lines; onsite wastewater erosion between RM 1.4 Culverts create barriers to
00 Higher storm flow levels disposal and 2.6 and erosion from fish at RM 1.95 and
also may be influenced land clearing activities Talbot Road;Large
by other human activities organic debris dams create
such as agriculture and barriers to fish at RM 1.8
hobby farming to 2.55; Erosion has
eliminated most pools
and benthic organisms at
RM1.8to2.55
ROLLING HILLS No problems observed High in storm flow; High in base and storm None observed High turbidity and Sedimentation at S 22nd
Major source is runoff flow;High base flow suspended solids in storm Court caused by upstream
from paved surfaces levels possibly due to flow probably caused by erosion due to drainage
leaking sewer lines, instream erosion and from Fred Nelson JHS
Higher storm flow levels erosion at construction has damaged fish habitat
also may be influenced sites;Oil sheen in area;Outfall at Benson
by other human activities frequently observed in Road eroding stream bank
such as agriculture and upper section of creek
hobby farming caused by unknown
source(s)
Table 9. Identified problems in Black River basin study area (continued)
HABITAT AND
PROBLEM SEDIMENT WATER QUALITY - WATER QUALITY - WATER QUALITY - WATER QUALITY - OTHER PHYSICAL
DEFINITION QUALITY METALS FECALS NUTRIENTS OTHER PROBLEMS
VALLEY High total organic High zinc in base flow High in base flow; High High total phosphorus in Elevated temperature and Little vegetative cover,
carbon,metals,and total caused by unknown base flow levels probably base and storm flows; low dissolved oxygen Deposition of sediments
petroleum hydrocarbons; source(s)upstream of due to malfunctioning Source of elevated during base flows transported from streams
Numerous study area;All metals onsite wastewater concentrations in base worsened by lack of draining the plateau has
industrial/commercial elevated in storm flow; systems upstream of flows may be both vegetative cover;Low damaged fish habitat and
facilities,two known Source includes runoff subbasin,or leaking natural and result of flows result from long- benthic organisms
contaminated sites, and from paved surfaces with sewer lines or illicit malfunctioning onsite term increase of
11 spills involving significant loading from connections; Higher wastewater systems impervious surface
oil/petroleum and upstream of study area storm flow levels may be upstream of subbasin or coverage and loss of
hazardous materials influenced by other leaking sewer lines; wetlands in basin, High
reported in 1990-91 in human activities such as Source of high levels in turbidity and suspended
basin could contribute to agriculture and hobby storm flows probably solids in storm flow
sediment contamination farming also includes fertilizer probably caused by
application and erosion upstream instream bank
from land clearing erosion and erosion from
activities construction sites
SOUTH RENTON High total organic High in base and storm High in base and storm High total phosphorus in Elevated temperature and Sediment deposits in
carbon,metals,and total flow;Source of elevated flow;High base flow base and storm flows; low dissolved oxygen pumping station forebay
petroleum hydrocarbons; levels in base flows is levels probably due to Source of high levels in during base flows reduce flood storage and
high pesticides and PCB's unknown;Source of high malfunctioning onsite base flows may be both worsened by lack of water treatment
at mouth of Springbrook levels in storm flows wastewater systems natural and result of vegetative cover;Low capabilities
Creek;Sediments includes runoff from upstream of subbasin, malfunctioning onsite flows result from long-
removed from forebay paved surfaces; leaking sewer lines,or wastewater systems term increase of
may require special Significant loading from illicit connections; upstream of subbasin or impervious surface
attention for disposal upstream of study area Higher storm flow levels leaking sewer lines; coverage and loss of
(i.e.upstream of valley also may be influenced Source of high levels in wetlands in basin;High
subbasin) by other human activities storm flows probably turbidity and suspended
such as agriculture and also includes fertilizer solids in storm flow
hobby farming application and erosion probably caused by
from land clearing upstream instream bank
activities erosion and erosion from
construction sites
16. SOURCE CONTROL ALTERNATIVES STRATEGY
CONTROL ALTERNATIVES
The following alternatives focus primarily on the control of urban runoff pollutant sources
rather than treatment. The control of pollutant sources is preferred over treatment options
because source control automatically reduces the amount of pollutants released to the
environment and because source control is less costly than treatment.
Control of Runoff Pollutants from Commercial and Industrial Areas
Commercial and industrial areas within the Black River basin have a potentially significant
influence on the quality of stormwater runoff and downstream receiving waters. Therefore,
control of these sources either through retrofitting of existing facilities or operational controls
for new facilities are proposed. Depending upon the type of facilities, various best
management practices (BMPs) or combinations of BMPs may be appropriate. Specific
controls that could be implemented to reduce stormwater pollutants in commercial and
industrial areas include the following:
■ Enclosure or covering of outside activities
■ Waste segregation
■ Storage containment
■ Spill response plan
■ Elevation out of the floodplain (for storage).
Under the new National Pollutant Discharge Elimination System (NPDES) regulations,
stormwater runoff from certain industrial facilities and construction sites larger than 5 acres
will be required to obtain an NPDES permit. Industries for which NPDES stormwater permits
are required are identified based on their standard industrial classification (SIC) designation.
The SIC codes pertaining to the facilities operating in the Black River basin include the
following:
26 Paper and allied products
28 Chemical and allied products
29 Petroleum refining and related industries
32 Stone, clay, glass, and concrete products
34 Fabricated metal products
42 Motor freight and warehousing
5015 Wholesale trade: used motor vehicle parts
5093 Wholesale trade: scrap and waste materials.
Fewer than 20 of the existing industrial facilities in the Black River basin are required to
obtain NPDES permits. These facilities are required to file a notice of intent with Ecology for
coverage under Ecology's baseline general permit by October 1, 1992. In addition, each of
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these facilities is required to prepare a stormwater pollution prevention plan by October 1,
1993 and to implement the plan by October 1, 1994.
The two most common industrial categories operating in the basin (which include about 59
businesses) are automotive repair and service stations. However, at this time, neither of these
industrial categories is required to obtain an NPDES permit.
Control of Runoff Pollutants from Residential Areas
Water quality may be adversely affected by runoff from existing residential areas within the
basin. Residential activities, such as improper disposal of household hazardous wastes, may
be controlled through various means. Various techniques for control are identified and
addressed more specifically elsewhere as separate source control alternatives. Additionally,
residential pollutant runoff control generally includes, as a key component, the dissemination
of information and education regarding the following:
■ Environmentally friendly consumer products
■ Availability of toxic household product disposal
■ Locations of used oil recycling centers
■ Signage programs for streams and storm drains
■ Local school education programs
■ Stream enhancement projects.
Control of Construction Activities and Resulting Runoff
Construction activities can cause high sediment and phosphorus loading in receiving waters as
a result of the exposure and disturbance of soils. This problem is particularly acute in rapidly
developing urban areas and may be a significant contributor to poor water quality in the Black
River basin. This suggests that increased efforts at controlling runoff from construction sites
are warranted. Control of runoff from construction activities includes the following:
■ Limiting the area disturbed
■ Limiting contact of water with disturbed areas
■ Treating water that comes into contact with disturbed areas.
Successful implementation of these controls requires not only good design but also regular
inspection and maintenance of facilities. Adequate review and inspection implies increased
fiscal and staffing burdens for the city.
Water Quality Monitoring Program
To verify the effectiveness of controls implemented as part of any of these alternatives, an
ongoing water quality monitoring program is needed. This program would focus on the water
quality parameters of concern for various streams and wetlands -within the basin. The data
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collected would be used to modify or adapt, as necessary, the various alternative controls
implemented.
Runoff/Water Quality Public Education Program
The behavior of individuals and organizations has significant effects on nonpoint source
pollution. The most effective tool is a combination of regulation and education. Education is
a necessary complement to regulation, because prevention is the most effective deterrent.
Education can be a key influence resulting in awareness of the impacts of runoff and
implementation of BMPs. Information on proper storage and disposal of waste as well as
stenciling and signage programs have been effective educational tools in other jurisdictions.
Drainage Facility Operation and Maintenance Program
Without adequate maintenance, even properly designed stormwater systems rapidly lose their
effectiveness in detaining and treating stormwater. More frequent inspection and maintenance
of stormwater systems would likely result in improved water quality in the Black River basin.
Renton does not have a regular inspection program for private stormwater facilities. The
experience of other jurisdictions that have regular programs of inspection suggests that the
private facilities in Renton are probably poorly maintained. Renton currently cleans its catch
basins and storm drain piping on a 5-year cycle. The experience in other jurisdictions suggests
that once per year should be the target cleaning frequency.
Protection and Acquisition of Wetlands
Aside from their value as wildlife habitat, wetlands can remove pollutants from runoff and
provide water storage capacity, reducing the adverse effects of downstream flooding. Water
quality data indicate, for example, that the Panther Creek wetland acts to reduce phosphorus
loadings downstream of the wetland. Existing regulations at the federal, state, and local levels
protect wetlands from the direct impacts of filling and other disturbance. A fuller measure of
protection is provided by public acquisition of wetlands. Public ownership would reduce the
potential for inadvertent or illicit disturbance of wetlands.
Stream and Stream Bank Protection and Rehabilitation
Stream channel and stream bank degradation has occurred at various places within the basin as
a result of excessive flows and inadequate historical stream management practices. A program
to rehabilitate existing stream banks and channels in the lower basin should focus on arboreal
plantings that would also provide shade and habitat improvement for fish. In steep-sloped
areas of the upper basin, structural controls may be necessary to reduce erosion and stream
bank cutting that threatens downstream wetlands and aquatic habitat. Appropriate structural
controls could include the following:
■ Gabions (wire cages filled with stones)
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■ Riprap (a loose assemblage of broken stones)
■ Tightlining (piping) of surface drainage.
Emergency Spill Response, Containment, and Cleanup
Local fire districts, including the city fire department, currently handle emergency spill
response and inspect businesses under the Uniform Fire Code to review the handling and
storage of flammable materials. While present procedures are generally effective in
responding at the point of spillage, a more broadly based program that includes regular
monitoring at high risk and downstream locations as well as a comprehensive information
network would reduce the risk from spills.
Household Hazardous Waste Collection Program
It is proposed that the city, in conjunction with King County, continue to actively promote and
sponsor a household hazardous waste collection program. The city currently is a participant in
the Local Hazardous Waste Management Program, an interagency program established for the
management of hazardous wastes in the King County region. This program, developed and
implemented by Seattle-King County Department of Public Health, Seattle Solid Waste Utility,
King County Solid Waste Division, Metro, and suburban cities, currently provides collection
and disposal services for household hazardous wastes. In addition, a variety of education
programs are administered to re-educate the public about proper use, storage, and handling of
household hazardous wastes. Businesses defined by the state of Washington as small-quantity
generators are also addressed under this program. The city actively participates in the
management of the program and sponsors two targeted waste collection events each year in
addition to assisting in the promotion of the education and collection activities implemented by
the other participating members.
Flood Control and Other Capital Improvement Programs
Existing or planned capital improvement projects within the study area are described in
Chapter 14. The city is currently addressing flooding issues within the basin as part of the
ESGRW Plan. This program is incorporating water quality and habitat findings of the Black
River Basin Water Quality Management Plan into flood control alternatives for the basin. The
flood control program should continue to coordinate with those control alternatives identified
as part of the Black River plan, and where possible, to incorporate flood control techniques
protective of water quality within the basin.
City Integrated Pest Management Plan
Development and use of an integrated pest management (IPM) plan by the city will ensure that
ongoing and future use of pesticides, herbicides, and other toxic chemicals by city personnel is
protective of water quality within the basin. Such a plan will document the types of chemicals
to be used (particularly near streams), application rates, and spill response measures to be
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followed. This plan will serve to limit the use of chemicals to those that are least toxic and
absolutely necessary for proper management of city properties.
Regulatory Controls
Regulatory controls allow local jurisdictions to enforce compliance with water quality policies
and standards. Adequate enforcement is necessary if regulatory controls are to be effective.
For example, design of new stormwater systems reflects the current state of engineering
knowledge, but the systems are in some cases ineffective because post-construction inspection
and maintenance are inadequate. In addition, advances in understanding of water quality
issues periodically create the need to update particular regulations. Various regulatory controls
that could be implemented by the city to protect water quality are identified in the following
section.
RECOMMENDED IMPLEMENTATION STRATEGY
Approach
Water quality sampling, field observations, and discussions with city and other agency
personnel have revealed the existence of various water quality problems in the Black River
basin. For many of these problems, the sources are known or limited to a small number of
possibilities. In some cases, this study has located specific causes of water quality problems.
More typically, however, sources have been only generally identified and associated with a
general type of land use or human activity.
For example, high fecal coliform bacteria levels observed in base flows of Springbrook Creek
and other water bodies in the study area almost certainly result from contaminants entering
these streams via the ground water, since ground water provides the sole source of base flows.
The most likely causes of high levels of fecal coliform bacteria in ground water are
inadequately functioning onsite wastewater systems, leaking sewer lines, illicit sewer
connections, and nonhuman animal waste. While this study has identified this problem and its
probable causes, the scope of the study does not allow identification of specific sources (for
example, specific onsite wastewater systems, individual sewers that are malfunctioning, or
specific illicit connections).
Based on these considerations, a two-tiered implementation strategy for source control is
proposed, involving 1) actions to further define the extent of water quality problems and
pinpoint their sources, to provide an adequate focus for 2) actions to resolve existing problems
and improve water quality, as well as to prevent future problems. These recommendations
focus first on identifying and controlling sources of pollutants. To the extent that source
control may not be feasible, downstream capital improvement projects should then be
considered.
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Specific Actions
The relationships among specific actions are shown in Figures 8 and 9. The specific actions,
listed and explained below, are identified by number but have not been ranked.
Action 1: Develop and implement plan for ongoing monitoring of water and sediment
quality and physical characteristics of streams
The sampling that was conducted for the Black River plan should be continued and modified as
necessary to provide data that will measure the success of this program and to provide
information useful in other actions. The monitoring plan that is developed should include
water and sediment quality sampling as well as periodic inspections of streams in the study
area. Water and sediment quality monitoring should include stations in the Springbrook
Springs subbasin, which was not monitored during this study. Inspections of streams should
focus on signs of excessive erosion, flow blockages, and other physical indications of water
quality problems.
As a beginning step in a stream inspection program, the city should inventory basin stream
channels to identify areas that are subject to erosion. Stream bank stabilization may be an
appropriate measure along some stream segments to reduce erosion and resultant downstream
sedimentation. Stream bank stabilization projects identified as a result of this action would be
implemented through Action 14E.
Action 2: Initiate ongoing public involvement and education program as developed by
citizen task force
The citizen task force developed a recommended public involvement and education program
that includes the following elements:
■ Placing signs to identify valuable environmental resources and
integrating signage with city trail plans
■ Quarterly or half-yearly mailings of fact sheets, with each mailing
directed to a different audience or different focus
■ A committee of representatives from automobile supply stores and
related businesses and interested citizens that would implement an
education program for the do-it-yourself oil changer
■ Newspaper articles on different aspects of Black River basin planning
■ Stream cleanup with an emphasis on litter control
■ A Renton River Days booth to provide information to the public on
surface water management in Renton
■ A program to decrease individual dependence on hazardous materials
and increase knowledge of alternatives to hazardous materials
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I
Actions 1-17
City of Renton
Actions
Modify
Improved Water Quality
Water Quality Program
0
Action 18
Year End
Assessment
Figure 8. Implementation Strategy Black River Basin Water Quality Management Plan
Action Action 1 Action 4 Action 5 Action 3 Action 6 Action I
Inventory Inventory Improve
Monitoring Non-Sewered Hobby I & I Functioning nctioning of Monitoring
Plan Areas Farms Sewer Study Existing Stormwater Plan
Systems
. .................... ........... .. .........- ...
............. ...................... ......... .......... ....................
............................... .. .............. .......... ............. ....................... .............I�....
........................ ................... ..............................................
Action 16
Review Existing
Revenue Sources
...........-........................................ ............ .....
..........
Actions 8 & 17 Action 2 Action 14
Action 15
Increase
Public Capital
Coordination Investigate
with Other Improvement
Education and End-of-Pipe
Programs
Treatment
Jurisdictions Involvement
..............................
..........
Action 18 Action 18
Action 7 Year End Assessment Year End Assessment
Action 9
Increase
Establish
Coordination
Procedures for
Between City
Water Quality
Utilities
Violations
.... .................. ........ . .....
Improved
Action 12 Water Quality
Action 10
Improve Treatment Establish Improved
of Runoff from Control for
Existing Public
Runoff from
Facilities > construction Sites
Action 13 Action 11
Consider
Prepare IPM
Alt. Mosquito
Plan Control
A
......................... .....-.................
Figure 9. Implementation Actions Black River Basin Water Quality Management Plan
108
■ Educating gardeners and small farmers about the effects of chemical use
on water quality and promoting proper use of chemicals.
An additional element should be development of a local public school program on water
quality. The Washington State Office of Environmental Education has prepared a curriculum
entitled Clean Water, Streams and Fish, A Holistic View of Watersheds, designed for
elementary instruction. To the extent possible, the city should promote inclusion of this or
similar general materials into local school curricula and should provide information specific to
the city's efforts in the Black River basin and other basins within its jurisdiction.
As the overall water quality management program proceeds, a need may arise for focusing
particular elements of the education program. For example, the results of Action 5 may
indicate the need for a focused education effort in conjunction with the Soil Conservation
Service targeting owners of hobby farms.
Action 3: Coordinate with Metro and Soos Creek Water and Sewer District to develop
and implement inflow and infiltration (I&I) study and locate illicit sewer connections
High fecal coliform levels in base flows in Springbrook Creek and other water bodies in the
study area may be caused in part by leaking sewer lines or illicit sewer connections.
Surcharging of sanitary sewer lines may contribute to elevated bacteria levels observed during
storm events. The proposed ongoing monitoring program (Action 1) can provide data enabling
the sources of elevated bacteria concentrations to be traced to specific drainage inputs.
Pinpointing specific sources, however, can be costly and time-consuming. For sewer leaks, a
first step could be to embark on a video inspection program of the older, major distribution
and trunk lines in the study area. This relatively cost-effective procedure could detect major
leaks. Detecting smaller, more widely dispersed leaks or pinpointing illicit sewer connection
would require dye/mass balance or chemical detection studies that may be more costly.
Action 4: Coordinate with Seattle/King County Health Department to inventory
unsewered areas
High fecal coliform levels in base flows in Springbrook Creek and other water bodies in the
study area may be caused in part by malfunctioning onsite wastewater disposal systems. The
entire study area is included within either the city sewer service area or the Soos Creek Water
and Sewer District sewer service area. However, some older developments within both
service areas remain unsewered. Some onsite wastewater systems within these unsewered
older developments may have failed or may not otherwise be providing adequate treatment of
effluent.
Action 5: Inventory hobby farms
The city, in coordination with the Soil Conservation Service, should inventory hobby farms
within the study area to assess whether current practices on these farms may be contributing
significant amounts of nutrients and fecal coliform bacteria to receiving waters. These
contaminants have been found at elevated levels in storm flows in streams throughout the study
area. The Soil Conservation Service operates a program o provide the agricultural community
with information on management practices that preserve water quality. If the inventory
109
recommended here reveals potential pollutant sources, the Soil Conservation Service could
focus an education program in those problem areas.
Action 6: Improve the functioning of existing stormwater drainage systems through a
program of inventory, inspection, and maintenance
Urban runoff from residential, industrial, and commercial developments can contribute
significant amounts of metals and other hydrocarbons to surface waters during storm events.
In addition, the characteristics of urban development can cause higher temperatures and lower
dissolved oxygen in receiving streams.
Action 6A: Inventory existing stormwater drainage systems
At the present time, the city does not regularly inspect private stormwater facilities and takes a
reactive approach to maintenance problems. The city needs a comprehensive understanding of
how well existing stormwater facilities are functioning.
The first step in implementing this action would be for the city to review its documents for
existing developments, including as-built drawings associated with final plats and multifamily
and nonresidential building permits. Document review should be followed by field inspection
of all known stormwater facilities. Field inspection should focus on whether the inlets and
outlets to storage facilities are clear and whether the facilities otherwise appear to function as
designed. In addition, the existence or absence of treatment facilities (e.g., swales, dead
storage) should be assessed. Finally, the existence of specific problems should be
documented. As an example, many stormwater systems adjacent to Panther Creek and the
Springbrook Springs tributary have their outlets positioned so that the discharge cascades onto
the stream bank, causing erosion and resulting in elevated turbidity levels in receiving waters
during storm events. The city should compile the data gathered into a readily accessible
ongoing database.
Action 6B: Implement a regular program of inspection and maintenance of all
stormwater facilities
This plan proposes that the city establish a goal of inspection and maintenance of all
stormwater facilities on a 1- to 2-year rotation. For public facilities, the city should increase
its present frequency of cleaning from once every 5 years to the target frequency. Reaching
the target frequency for inspection and maintenance on private facilities will require a more
involved process. The city must assess its existing policies and requirements as well as the
conditions applicable to older private stormwater facilities. This would allow an assessment of
any revisions to ordinances and existing contractual relationships that may be necessary in
order for the city to implement a program covering private facilities. The city could either use
its staff to inspect and maintain private facilities or contract with a private vendor for this
purpose.
110
Action 7: Increase coordination among city utilities and within the Public Works
Department
Actions taken by various city utilities can affect water quality. At the same time, the quality
of surface waters and ground waters can affect services provided by city utilities. To provide
a forum for periodic discussion among city utilities on the subject of water quality, this plan
proposes initiation of a water quality committee internal to the Public Works Department for
the purpose of exchanging information relevant to city programs on water quality. This
committee would include representatives of the drainage, water, sewer, and solid waste
utilities and the transportation division. The water quality committee could also include a
planning department representative to provide input on land use planning concerns and
proposed development.
Action 8: Increase coordination with Kent
Water quality sampling conducted for this study demonstrates that significant loadings of
pollutants in the Springbrook Creek system originate upstream of Renton's jurisdiction. Many
of the sources of these elevated pollutant levels are located in Kent. Kent has been conducting
water quality studies and has prepared a five-year water quality plan intended to improve water
quality within its jurisdiction. This plan recommends that Renton and Kent establish a joint
Black River basin working group to coordinate efforts on water quality and other appropriate
public works by the two cities.
Action 9: Establish procedures for responding to water quality violations
Renton currently has a code enforcement officer who operates under the city code section on
civil violations. A clear procedure should be established whereby the water utility identifies
apparent code violations and then refers the matter to the code enforcement officer for
enforcement. Violations of city code that affect water quality include illegal dumping of toxic
materials in water or on land and illicit clearing and grading activities that can result in
increased erosion and sedimentation.
Action 10: Establish improved controls on the quality of runoff from construction sites
Erosion from construction activities can contribute significant amounts of sediment to receiving
waters. Experience in other jurisdictions indicates that inspection and enforcement of required
erosion and sedimentation control devices, structures, and actions at construction sites does not
occur on a sufficiently frequent basis. Temporary erosion control facilities are often
inadequately maintained by construction contractors. The city should review its existing
inspection and enforcement program to determine necessary procedural changes and staffing
levels required to achieve adequate control at construction sites.
Action 11: Consider alternative methods of mosquito control in the Panther Creek
wetland
The city has applied a biological chemical (methoprene) in the Panther Creek wetland in recent
years in an attempt to control mosquito populations in the area. The. treatment has been
performed and monitored by a licensed professional entomologist in accordance with the
ill
chemical label, Ecology permit, and other governmental requirements. The city has also
conducted an annual wildlife census each year since 1989 prior to treatment to determine the
impact, if any, of the treatment on the existing fauna. According to a comparison of annual
wildlife census reports for 1990 through 1992, no impacts attributable to treatment of the
wetland could be identified. However, the city has considered and should continue to consider
alternatives to the biological chemical currently applied.
Action 12: Seize opportunities to improve treatment of runoff from existing public
developments
When Renton expands or modifies portions of its existing infrastructure, the city should
consider improving stormwater detention and treatment. For example, when widening its
roadways, the city could be required to provide stormwater detention and treatment for runoff
from the new pavement that meets contemporary standards. Where the city faces such
improvement projects, it should, if feasible, construct facilities sufficient to handle runoff from
the previously existing impervious areas as well as the new pavement.
Action 13: Prepare an integrated pest management plan for city use of pesticides,
herbicides, and other chemicals
The city maintains a large acreage of park space, roadsides, and other open space using
mechanical and chemical methods. At the present time, the city has no integrated
methodology for the use of chemicals. Development of an integrated pest management (IPM)
plan would ensure that ongoing and future chemical use by city personnel is protective of
water quality within the basin and elsewhere in the city. An IPM plan would specify types of
chemicals to be used, application rates, storage and handling procedures, and spill response
measures.
Action 14: Capital improvement projects
Action 14A: Remove sediments from the forebay
Sedimentation in the Black River pump station forebay has degraded wildlife habitat and
reduced the water and sediment storage capacity of the P-1 pond, thereby diminishing the
pond's flood storage capacity and its water treatment efficiency. The city of Renton, King
County, and the Soil Conservation Service should work together to dredge and'dispose of
accumulated sediments and to develop thresholds and procedures for future routine
maintenance. Sediments dredged from the forebay may be eligible for disposal at the King
County Cedar Hills landfill.
Action 14B: Stream cleanup (also part of Action 2)
Casual inspection of segments of Panther Creek and the Springbrook Springs tributary reveals
a wide variety of discarded material, ranging from old automobiles to construction debris,
located in or adjacent to the streambed. The presence of chemical containers (e.g., empty
bleach containers) suggests that illegal dumping, in addition to potentially obstructed flow,
may contribute to degraded water quality in the drainages..originating:on the plateau. This
problem can be addressed in a two-pronged approach: 1) public education (Action 2), and 2)
112
improved enforcement of illegal dumping regulations (discussed for water quality violations
under Action 9). The stream cleanup program could be modeled on similar programs in other
jurisdictions. Stream cleanup is included here as a capital improvement project, because
removing larger debris (e.g., abandoned cars) may require specific project funding from the
city. Cleanup efforts should be repeated as necessary.
Action 14C: Implement recommendations of the East Side Green River Watershed Plan
Implementation of some of the recommendations of the ESGRW Plan would positively affect
water quality in the study area. These recommendations include:
■ Reestablishing Panther Creek
■ Channel improvements between Grady Way and SW 16th Street
■ Reestablishing vegetation along stream corridors
■ Construction of P-9 spawning channel.
Action 14D: Construct capital improvements to correct specific problems in subbasins
tributary to Springbrook Creek
Reconnaissance observations during monitoring for this study revealed several specific
problems on drainages tributary to Springbrook Creek that will require capital improvement
projects to correct. The projects listed below are in addition to those described elsewhere in
other actions.
■ Culvert replacement at Talbot Road to improve fish passage
(Springbrook Springs tributary)
■ Culvert replacement at SR-167 to improve fish passage (Springbrook
Springs tributary)
■ Culvert replacement at river mile 1.95 to improve fish passage (Panther
Creek)
■ Culvert replacement at Talbot Road to improve fish passage (Panther
Creek)
■ In coordination with the local school district, retrofit of Fred Nelson
Junior High School with appropriate stormwater facilities to reduce
downstream erosion (Rolling Hills)
■ Modification of the outfall at Benson Road to reduce stream bank
erosion (Rolling Hills).
Results from other actions described here will likely reveal additional specific problems
requiring correction through capital improvement projects. For example, the stream inspection
program described in Action 1 may reveal outfalls that result in stream bank erosion, like the
one at Benson Road.
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Action 14E (future optional): Future capital improvements
Other actions in this program may reveal the need for additional capital improvement projects.
For example, if, after implementation of Action 613, information from Action 1 continues to
reveal excessive storm flows or water quality problems during storm events in particular
receiving waters, the city should assess whether these problems are caused by inadequate
existing stormwater systems. If problems are caused by malfunctioning existing systems, the
city should embark on a program of retrofitting older developments. This would involve
completing a detailed inventory of existing systems that may contribute to the problem area
and targeting those systems most in need of replacement or upgrading. In addition,
implementation of the city's wetland mitigation bank project could provide additional water
quality and habitat enhancement.
As another example, most of the original riparian habitat along Springbrook Creek has been
lost through human activities. Riparian habitat is valuable in itself and is critical in
maintaining the value of adjacent instream habitat. The city should inventory riparian habitat
and existing land use and ownership along Springbrook Creek. Based on this inventory, the
city should develop a capital improvement plan to add vegetation along the creek to provide a
more natural setting and improve riparian habitat.
Action 15: Investigate end-of-pipe treatment for drains contributing significant pollutant
loadings to Springbrook Creek
Although controlling water pollution at the source is preferable to controls downstream from
the source, identifying sources of nonpoint pollution can be difficult, particularly in urban
areas that have many potential individual sources. End-of-pipe treatment may then be an
appropriate additional control to assure adequate water quality in receiving waters. End-of-
pipe treatment can also moderate the downstream effects of pollutant spikes resulting from
spills or other uncommon events. Monitoring during this study has identified large pollutant
loadings entering Springbrook Creek from the Kent drain, the Rolling Hills drain, and other
enclosed sources. The city should investigate the feasibility of constructing wetlands, wet
ponds, or bioswales to provide treatment of these piped discharges prior to their entry into
Springbrook Creek.
Action 16: Review existing revenue sources and seek adequate funding from the Renton
City Council
The actions described here will require additional revenue for the implementation of new
programs or the expansion of old programs. In some cases additional revenue could be
generated by increases in existing permit fees. For example, the results of Action 10 may
reveal a need for additional staff for inspection and enforcement at construction sites. If such
a need exists, the city could consider increasing certain land development permit fees to at
least partially provide the additional revenue required.
Action 17: Establish a protocol for determining proper future actions
Several facilities within the Black River basin, such as the P-9 channel, are within the
jurisdiction or within the scope of interest of multiple agencies. Implementation of actions
114
affecting these facilities will require consensus among several agencies. The city, for internal
projects as well as regional water quality projects, should initiate development of a protocol
for selecting and implementing future actions. This protocol should assure that the necessary
individuals and agencies are involved in decision-making and that decision-making will
proceed in a manner consistent with the water quality goals of the city.
Action 18: Assess effectiveness of the program at the end of each water year
The city should periodically assess the effectiveness of its efforts and modify the Black River
basin program as necessary. Assessments would logically occur at the end of each water year
(October through September), although funding cycles may dictate different timing. The
yearly assessment and any resulting recommendations should be presented to the Renton City
Council and, if necessary, other agencies and jurisdictions.
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17. REFERENCES
Allmendinger, H. 1990. Personal communication of February 14, 1990. King County Black
River pump station, Renton, WA.
Alhmendinger, H. 1992. Personal communication of February 11, 1992. King County Black
River Pump Station, Renton, WA.
Burke, S. 1992. Personal communication of July 27, 1992. King County Solid Waste
Division, Seattle, WA.
Converse. 1989. Mill Creek environmental assessment, Kent, Washington. Prepared for
R.W. Beck and Associates, Seattle, WA. Converse Geoenvironmental Services, Seattle, WA.
Cropp, T. 1992. Personal communication of February 10, 1992. Washington Department of
Wildlife.
Ecology. 1991. Summary of criteria and guidelines for contaminated freshwater sediments.
Compiled by J. Bennett and J. Cubbage, Environmental Investigations and Laboratory
Services, Washington Department of Ecology, Olympia, WA.
Ecology. 1992a. Unpublished PC STORET data provided by B. Hopkins, Washington
Department of Ecology, Olympia, WA.
Ecology. 1992b. Stormwater management manual for the Puget Sound basin.
Fitch, L. and T.C. Rolla. 1991. Ground water quality issues related to the use of pesticides
and fertilizers. Draft issue paper. USDA Soil Conservation Service and Seattle-King County
Department of Public Health.
Franz, D.D. 1991. Unsteady flow solutions: Notes for short course on FEQ and unsteady
flow.
GRCC. 1992. Unpublished data provided by John E. Fohn, Green River Community
College, Kent, WA.
Hart Crowser. 1992. Free phase product recovery system--Renton, Washington bulk terminal
facility. Quarterly Progress Report: May 1992. Prepared for Mobil Oil Company by Hart
Crowser, Inc., Seattle, WA.
Kent, City of. 1991. Water quality program, 1992-1996. Prepared for Kent Public Works
Department by Resource Planning Associates.
King County. 1987. Basin reconnaissance report No. 14: Black River basin. Natural
Resources and Parks Division and Surface Water Management Division, Seattle, WA.
117
Krom, S. 1990. Personal communication of February 14, 1990. Citizens for Renton
Wildlands Preservation.
Landau. 1991b. Quarterly interpretive report, 3d quarter 1990, Western Processing Phase II.
Prepared for Western Processing Corporate Trustee by Landau Associates, Edmonds, WA.
Linders, C. 1992. Personal communication of July 23, 1992. PEI/Barrett Consulting Group,
Bellevue, WA.
Margalef. 1968. Perspectives in ecological theory. University of Chicago Press, Urbana, IL.
Marine Science Society. 1991. Puget Soundbook. Puget Sound Water Quality Authority and
Municipality of Metropolitan Seattle.
Metro. 1990. Quality of local lakes and streams: 1988-1989 status report. Prepared by
Water Resources Section, Municipality of Metropolitan Seattle.
Metro. 1991. Quality of local lakes and streams: 1989-1990 update: Prepared by Water
Resources Section, Municipality of Metropolitan Seattle.
Metro. 1992. Unpublished data provided by R. Brenner, Water Resources Section,
Municipality of Metropolitan Seattle.
Meyer, M. 1992. Personal communication of February 1992. Planning Department, City of
Renton, WA.
Northwest Hydraulic Consultants. 1991. East side Green River watershed hydrologic
analysis. Prepared for R.W. Beck and Associates and City of Renton, Department of Public
Works, by Northwest Hydraulic Consultants, Inc., Kent, WA.
Penhale, B. 1992. Personal communication of February 13, 1992. Washington Department
of Ecology, Bellevue.
Persaud, D., R. Jaagumagi, and A. Hayton. 1992. Guidelines for the protection and
management of aquatic sediment quality in Ontario. ISBN 0-7729-9248-7. Water Resources
Branch, Ontario Ministry of the Environment, Toronto, Canada.
Puget Sound Water Quality Authority. 1991. Public involvement and education model
projects fund: 47 success stories from Puget Sound.
Renton. 1981. Earlington Park final environmental impact statement. City of Renton, WA.
Renton. 1990. Black River Corporate Park Tracts A and B office buildings, draft
environmental impact statement. Prepared for the City of Renton by Jones & Stokes
Associates, Inc., Bellevue, WA.
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Renton. 1991. Black River Corporate Park Tracts A and B office buildings, final
environmental impact statement. Prepared for the City of Renton by Jones & Stokes
Associates, Inc., Bellevue, WA.
R.W. Beck and Associates. 1992. Boeing CSTC facility floodplain analysis review.
Prepared for City of Renton, Washington.
Schneider, Philip. December 14, 1992. Personal communication (letter to Renton
Department of Public Works). Washington Department of Wildlife, Mill Creek, WA.
Seacor. 1991. Remedial investigation report, Sternco Renton and Sternco Industrial Renton
sites, SW 43rd Street and Oakesdale Avenue SW, Renton, Washington. Volume I of IV.
Prepared for Robert Goodstein, Woodley and Associates, Kirkland, WA by Seacor
Environmental Engineering, Bellevue, WA.
Sverdrup. 1992. Unpublished data provided by J. Schutt, Sverdrup Corporation, Kirkland,
WA.
Totchko, N. 1992. Personal communication of July 23, 1992. GeoEngineers, Inc., Seattle,
WA.
Tukwila, City of. 1992. Southeast central business district drainage study. Prepared by
Gardner Consultants, Inc., Seattle, WA.
U.S. EPA. 1977. Guidelines for the pollutional classification of Great Lakes harbor
sediments. U.S. Environmental Protection Agency, Region 5 (cited by Ecology 1991).
U.S. EPA. 1988a. Hydrologic Simulation Program, FORTRAN. U.S. Environmental
Protection Agency Environmental Research Laboratory, Athens, GA.
U.S. EPA. 1988b. Interim sediment criteria values for nonpolar hydrophobic organic
contaminants. SCD 17. U.S. Environmental Protection Agency, Washington, D.C.
U.S. EPA. 1992. Unpublished data provided by P. Millam, Superfund Branch, U.S.
Environmental Protection Agency, Region 10, Seattle, WA.
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Olympia, WA.
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18. GLOSSARY OF TERMS
Acre-foot — The volume of water, 43,560 cubic feet, that will cover an area of one acre to a
depth of one foot
Acute criteria — Contaminant concentrations that result in adverse human health or ecological
effects after a single, short-term exposure (e.g., 96 hours)
Adsorption — The process of pollutants adhering to the surfaces of solid materials
Alkalinity — A measure primarily of the carbonate or carbon dioxide-related compounds in
water; the lower the alkalinity, the less capacity the water has to absorb acids without
becoming more acidic
Ammonia (NH3) — A nitrogen-containing substance whose presence may indicate recently
decomposed plant or animal material
Base flood — The 100-year flood, or that flood having a one percent chance of being equaled
or exceeded in any given year
Base flow — The water that flows in a stream in the absence of rainfall-supplied runoff water
(the source of base flow may be lakes, snowmelt, or discharge of ground water into the
stream)
Bed load — The sediment in a stream channel that mainly moves by jumping, sliding, or
rolling on or very near the bottom
Benthic organisms — The organisms living in or on the bottom sediments of a water body
Best management practices (BMPs) — Structural or nonstructural controls used to treat
urban stormwater runoff
Biochemical oxygen demand (BOD) — A measure of the quantity of oxygen consumed
during the biochemical oxidation of matter over a specified period of time (materials such as
food waste and dead plant or animal tissue use up dissolved oxygen in the water when they are
degraded through chemical or biological processes)
Chronic criteria — Contaminant concentrations that result in adverse human health or
ecological effects after continual, long-term exposure
Conductivity — A measure of the capacity of water to convey an electric current; because
conductivity is related to the total amount of dissolved charged substances in the water, it can
be used as a general indicator of water quality and can also suggest the presence of
unidentified material in the water (conductivity is often used as a surrogate for salinity
measurements)
121
Contaminant — Any hazardous substance that does not occur naturally or is found at
concentrations greater than natural background levels
I
Conventional parameters — Water or sediment properties that are routinely measured and
analyzed in assessing water or sediment quality, such as temperature, conductivity, turbidity,
pH, dissolved oxygen content, and grain size
Criteria — Numerical values for characteristics and constituents of water that are considered
appropriate for aquatic life or human use of the water
Design storm — A rainfall event of specified size and frequency (for example, a storm that
occurs only once every 10 years) that is used to calculate runoff volume and peak discharge
rate
Detection limit — The smallest concentration or amount of a constituent that can be measured
by a single measurement with a stated level of confidence (in practice, detection limits can be
determined by different methods in different laboratories and are not always assigned a
statistical level of confidence)
Dissolved oxygen — Oxygen that is dissolved in water (certain amounts are necessary for life
processes of aquatic animals; oxygen is consumed by animals, plants at night, and bacterial
decomposition of dead organic matter)
Fecal coliform bacteria — Minute organisms associated with human or animal feces that are
measured or counted as an indirect indicator of the possible presence of harmful bacteria
Flood, base — The 100-year flood, or that flood having a one percent chance of being
equaled or exceeded in any given year
Flood fringe — That portion of the floodplain not including the floodway that is generally
associated with slow-moving or standing water
Floodplain — The total area of the floodway plus the flood fringe subject to inundation by the
base flood
Floodway — The channel of a stream and any adjacent floodplain areas that, according to the
applicable flood hazard regulation, are reasonably required to convey the base flood flow and
must be kept free of encroachment so that the base flood can be carried without substantial
increase in flood height
Forebay — An extra storage area provided near an inlet to trap incoming sediments
Grain size — Average size of mineral particles composing a sediment
Ground water — Water stored beneath the surface of the earth, filling pores in soil, sand, or
gravel; ground water is supplied by the seepage of rainwater, snowmelt, and other surface
water into the soil (ground water discharges into lowland streams to maintain their base flow)
122
Habitat — The physical and chemical environment that provides all of the basic requirements
for life and enables an organism to successfully complete its life cycle (the habitat includes
food, shelter, and other elements such as oxygen and temperature)
Hardness — A measure of the concentration of dissolved calcium carbonate in water (hard
water has high concentrations and causes scaling in pipes, which increases frictional resistance
to flow)
Headwater stream — A stream forming the source of another larger stream
Heavy metals — Metals are naturally occurring elements; certain metals, such as mercury,
lead, nickel, zinc, and cadmium, can be of environmental concern when they are released to
the environment in unnatural amounts by human activities
Herbicide — A chemical pesticide designed to control or destroy plants, weeds, or grasses
Hydraulic loading — Volume of flow per unit of time
Hydrocarbon — An organic compound composed of carbon and hydrogen (petroleum and its
derived compounds are primarily hydrocarbons)
Hydrology — The science dealing with the properties, movement, and effects of water on the
earth's surface, in the soil and rocks below, and in the atmosphere
Impervious area — Impermeable surfaces, such as pavement or rooftops, that prevent the
infiltration of water into the soil
Invertebrates — Animals without internal skeletons, ranging in size from microscopic
creatures to insects, worms, and crayfish (in general, more varied invertebrate communities
living in streambed sediments indicate healthier streams)
Loading rate — The rate at which a substance is added to a water body (for example, streams
load nutrients to lakes at various rates, as in 500 kilograms per year[500 kg/yr])
Lowest effect criterion — A level of sediment contamination that can be tolerated by most
benthic organisms
Micrograms per liter (µg/L) — A measure of the concentration of a substance in a given
volume of water; equivalent to parts per billion
Micromho (µmho) — The unit of measurement for conductivity
Milligrams per liter (mg/L) — A measure of the amount or concentration of a substance in a
given volume of water; equivalent to parts per million
Nephelometric turbidity unit (NTU) — A unit of measure for turbidity
Nitrate+nitrite (NO3+NO2) — Forms of nitrogen that algae may use for growth
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Nitrogen — An element that is essential as a nutrient for growth of organisms
Nutrient — An element or compound that is essential for the growth of organisms (excessive
amounts of nutrients can lead to accelerated growth of algae and subsequent degradation of
water quality due to oxygen depletion; some nutrients can be toxic at high concentrations)
Organism — Any living thing; in fecal coliform counts, it refers to the number of bacteria per
unit of water (for example, 50 organisms per 100 mL)
Parameter — A quantifiable or measurable characteristic (water quality parameters include
temperature, pH, conductivity, dissolved oxygen concentration, and many others)
Pesticide — A general term describing any substance, usually chemical, used to destroy or
control undesirable organisms (pests); pesticides include herbicides, insecticides, algicides, and
fungicides
pH — A measure of the acidity of a solution on a scale of 0 to 14, with 7 representing a
neutral solution; a pH value less than 7 is acidic, and a value above 7 is basic (the pH of water
influences many of the types of chemical reactions that occur in it)
Phosphorus — An element that is essential as a nutrient for the growth of organisms. (In
western Washington lakes, phosphorus is usually the nutrient in shortest supply; therefore,
adding more phosphorus causes more algae to grow. Various measurements of phosphorus in
water samples are made, including total phosphorus and the dissolved portion of the
phosphorus [orthophosphorus].)
Pollutant loading — Pollutant mass per unit of time, calculated as pollutant concentration
times flow rate for a given time period
Polychlorinated biphenyls (PCBs) — A group of manmade organic chemicals, comprising
209 different but closely related compounds (congeners) made up of carbon, hydrogen, and
chlorine (if released to the environment, PCBs persist for long periods of time and can
concentrate in food chains)
Polycyclic aromatic hydrocarbons (PAHs) — A class of organic compounds, some of which
are persistent and cancer-causing, that are formed from the combustion of organic material and
are ubiquitous in the environment (PAHs are commonly formed by forest fires and by the
combustion of fossil fuels, and they often reach the environment through atmospheric fallout,
highway runoff, and oil discharge)
Riparian zone — A relatively narrow strip of land that borders a stream or river
Salmonids — Salmon and trout species of fish
Sediment — Minerals and organic material suspended in or settling to the bottom of surface
water bodies (certain contaminants tend to collect on and adhere to sediment particles)
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Semivolatile organic compounds — Organic (carbon-containing) compounds with moderate
vapor pressures that can be extracted from environmental samples using organic solvents (for
example, pesticides, PCBs, and many others)
Severe effect criterion — A level of sediment contamination that is detrimental to the
majority of benthic species; results in pronounced disturbance of sediment-dwelling organisms
Sheet flow — Runoff that flows over the ground surface as a thin, even layer, not
concentrated in a channel
Storm flow — The portion of flow that reaches the stream shortly after a storm event
Surface water — Lakes, rivers, ponds, streams, inland waters, saltwaters, and all other
watercourses
Suspended solids — Particles, both mineral (clay and sand) and organic (algae and small
pieces of decomposed plant and animal matter) that are suspended in water and transported in
stream flow
Tightlining — The piping of urban runoff to protect easily eroded stream channels from the
effects of high flow peaks
Turbidity — A measure of water clarity based on cloudiness caused by the suspension of
minute particles, usually algae, silt, or clay
Volatile organic compounds — Organic (carbon-containing) compounds with high vapor
pressures that evaporate readily
Volatile solids — The material in a sediment sample that evaporates at a given high pressure
Water quality criteria — Specific levels of water quality that are expected to render a body
of water suitable for its designated use; the criteria are based on specific pollutant properties
and levels that would make the water harmful if used for drinking, swimming, farming, fish
production, or industrial processes
Watershed — The land area, defined by topographic divides, that drains into a stream
Wetland — A habitat where the influence of surface water or ground water has resulted in
development of plant or animal communities adapted to aquatic or intermittently wet
conditions; wetlands include tidal flats, shallow subtidal areas, swamps, marshes, wet
meadows, bogs, and similar areas
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19. COMMENTS ON DRAFT WATER QUALITY MANAGEMENT PLAN
AND RESPONSES TO COMMENTS
Copies of comment letters on the draft Black River Basin Water Quality Management Plan,
which was circulated for review during March 1993, are included in this section. Responses
are provided following the comment letters.
Several comments that were provided to the Renton Surface Water Utility suggested revisions
to ESGRW Plan alternatives and evaluation criteria. The ESGRW Plan is a concurrent
planning effort undertaken by the city of Renton, and any modifications to the ESGRW Plan
alternatives must be considered within the context of that planning effort. For this reason, the
suggested modifications have not been incorporated here but will be considered in the ESGRW
Plan process.
127
CURT SMITCH s
Director 3tii ,Aay °' MAR 16 1993
STATE OF WASHINGTON C'Ty OF RENTON
DEPARTMENT OF WILDLIFE gineering Dept.
16018 Mill Creek Blvd. , Mill Creek, WA 98012-1296 Tel . (206) 775-1311
March 12, 1993
City of Renton
Department of Public Works
200 Mill Avenue South
Renton, Washington 98055
RE: BLACK RIVER DRAFT WATER QUALITY MANAGEMENT PLAN, PRELIMINARY
DRAFT
Thank you for incorporating some of my comments on the preliminary
draft of this water quality plan. The comments below are basically
for the localized improvements to Springbrook Creek and are the same
comments I made on the preliminary draft.
The following are my comments and concerns regarding this document:
Page 11, Alternative 2 - Localized improvements to Springbrook Creek
Paragraph 1 - WDW encourages the use of bridges and bottomless
culverts for crossing structures in fish bearing streams.
Paragraph 2 - Any storm drainage improvement should include biofilter
swales prior to discharge into Springbrook Creek.
Paragraph 4 - Changing water regime to have increased levels of water
during the summer may not be beneficial to the existing wetland plants
where hydration is proposed.
Paragraph 5 - WDW would support the improvements to reestablish a
stream channel between Springbrook and Panther Creek. The new channel
should be planned to minimize impacts to adjacent wetlands.
Paragraph 5b - The Rolling Hills stream originates in the vicinity of
South 22nd Court between Benson Road and SR 516. I have not surveyed
this stream for fish, but I have been told by local residents that
there are cutthroat trout in this stream. The headwaters of "Rolling
Hills Creek" should be shown on maps that are included in this
document. I do plan to survey this stream soon.
Diverting low flows which occur in the summer months will not aid
spawning fish. Both salmon and trout spawn when flows are high during
the fall and early spring. The diversion of low flow will benefit
rearing habitat in the new channel.
City of Renton
March 12, 1993
Page 2
Page 16, Alternative 3 - Flood Flow Diversion Channel/Springbrook
Creek Fisheries Flow Channel
Paragraph 1 - Another option could be to use the present Springbrook
channel as a stormwater bypass and construct a new meandered channel
sized for the 2-year frequency flow. The new channel would have the
appropriate buffers with planted native trees and shrubs and fish
habitat structures in the new channel. Wetland impacts would have to
be considered on all bypass proposals as stated in this plan.
Paragraph 4 - Could a combination of riprap and bioengineering correct
the erosion problem instead of a diversion.
Page 17, Preliminary Evaluation Alternatives - Wildlife should also be
included in the evaluation process. The various alternatives can
impact wildlife in both positive and negative ways; i.e. , wetland
manipulation and channel relocations.
Page 70, Water Quality Summary - Springbrook Springs Subbasin
Rolling Hills Subbasin - See previous comment (paragraph 8) .
Page 85, Existing Conditions: Wetlands Assessment
Mitigation and Enhancement Strategies
The Department of Wildlife recognizes the planning and effort that has
gone into the development of this plan. We will be looking forward to
working with the city in providing input into the various projects as
more details become available. The protection of water quality will
directly benefit our state's fish and wildlife resources.
If you have any questions, please call me at (206) 775-1311, extension
107.
Sincerely,
Philip Schneider
Habitat Biologist
PS:ks
cc: Joe Robel, WDF
Connie Iten, Olympia
935 Powell Ave SW
United States Soil Renton, WA 98055
Department of Conservation
Agriculture Service
April 2, 1993
Mr. Ron Straka O
Storm Water Utility
City of Renton
200 Mill Avenue South APR 5 1993
Renton , Washington 98055
Dear Ron : CITY OF RENTON
Engineering Dept.
Re: City of Renton
Black River Basin
DRAFT Water Quality Management Plan
Thank you for the opportunity to review the subject DRAFT Water
Quality Management Plan. SCS strongly supports water quality and is
willing to include applicable elements of the plan where possible in
the remaining segments of the East Side Green River (ESGR) Project .
The following are our comments on the DRAFT document :
Pages ix and x are the same as vi and vii .
Page 1 , last para: Wording gives impression that ESGR project
responsible for all drainage changes . Separate out last
sentence.
Page 7 , last para. : Change to read King County Conservation
District , instead of King County Conservation Service.
Page 8, para 2 : Add the Oakesdale Ave retaining walls and SW
16th Street bridge to the list of completed portions of the
ESGRP.
Page 15 , para 1 : Revise to say " . . . the channel bottom may become
a created wetland. " Change the wording of the last sentence to
say that " . . . the project may require provisions to prevent
dewatering of adjacent wetlands . " We have not seen any soil
mechanics or geologic data that shows that a deep excavated
channel in this location will definitely drain wetlands in the
area. This will have to be evaluated during the design process.
o
The Soil Conservation Service
Vis an agency of the
Department of Agriculture
Page 2
Page 15 , para 4: This section needs to be rewritten because the
proposed low flow channel through the I-405 box culvert is lower
than the existing bottom of Springbrook as it goes under I-405 ,
therefore most or all base flow would probably go through the
box. Without extensive excavation in the existing channel under
I-405, which WSDOT will not allow due to safety concerns , this
area would only be inundated during times of higher flows and
from backwater from the pump station . In addition there is
minimal riparian habitat under the I-405 bridge or immediately
downstream due to erosion and previous riprapping by WSDOT.
Page 87, statement 1 under future programmed projects : Change
Enlargement to Removal of the sediment deposits of the P-1
forebay. . .
There may be funding and other assistance available for the education
and information portions of this plan from the King Conservation
District if their assessment passes .
If you have any questions feel free to call me at 764-3325 .
Sincerely,
Roderick L. Den-Herder, P. E .
Project Manager
cc: Julian Meuer, SCS, Spokane WA
Ron Shavlik, SCS , Olympia WA
Joe Henry, SCS , Renton WA
210-1
March 23 , 1993 MAR 2,41993
CITY OF RENTON
Engineering Dept.
SUBJECT: BLACK RIVER WATER QUALITY MANAGEMENT PLAN
FUNDED IN PART BY WASHINGTON DEPARTMENT OF ECOLOGY
CENTENNIAL CLEAN WATER FUND GRANT NO G9200030
Dear Mr. Straka:
As a member of the' Citizen Task Force who has attended every review meeting
except the last one, I want to submit my suggestions in writing related to
making the water quality better in the Black River Water Basin.
My suggestions are as follows:
1. Create a clean water plan and follow through with action.
2 . Install blue and white fish signs with logo, "THIS STREAM IS IN YOUR
CARE" where streams cross under roadways. Likewise, install wetlands
signs with similar logo.
3 . Work with the State of Washington Department of Ecology and
Fisheries, City of Kent, and King County in bringing back clean water
to the Black River Basin.
4 . Locate upstream polluting sources that are contaminating the
Black River Basin streams.
5. Control and stop upstream polluting via education and working small
clean water projects into Public Works and private property projects.
6. Plan/build a trail system that follows/parallels the Black River
streams, and plan/build a wetlands interpretive/walkway system for
viewing wildlife.
I want to thank you, R.W. Beck, and others for the expert presentations and
work involved in preparing for the public meetings. Everyone did an excellent
job.
We have a very special water system• within the Black River Basin. Let's save
and improve on our ecology treasure for future generations.
Sincerely,
Art Madsen
2607 Morris Ave. S.
Renton, WA 98055
RESPONSES TO COMMENTS FROM OUTSIDE AGENCIES AND
CITIZENS
Philip Schnieder, Washington Department of Wildlife
Thank you for your comments regarding the flood control alternatives under consideration for
the East Side Green River Watershed (ESGRW) Plan. The city of Renton is developing the
ESGRW Plan concurrently with the Black River basin management plan and expects to
complete the ESGRW Plan by early 1994. The city will consider your comments as it refines
the flood control alternatives under consideration.
A reference to your recommendation regarding the inclusion of wildlife in evaluation criteria
for the ESGRW Plan has been included in the Preliminary Evaluation of Alternatives
discussion in the ESGRW Plan section of Chapter 3, Related Planning Efforts (page 20).
A reference to reports of cutthroat trout use of the upper Rolling Hills stream system has been
included in the Rolling Hills Subbasin section of Chapter 10, Water Quality Summary (page
77).
Thank you for your comments regarding development of this plan. The city of Renton looks
forward to working with the Washington Department of Wildlife and other state agencies as
the plan recommendations are implemented.
Roderick L. Den-Herder, U.S. Soil Conservation Service
The page duplication in the Executive Summary has been remedied.
The discussion in Chapter 1, Black River Basin History (page 1) has been revised to more
clearly indicate that drainage changes have occurred throughout the twentieth century and not
solely since 1966.
The specific changes you suggest within the ESGRW Plan section of Chapter 3, Related
Planning Efforts, have been incorporated into the text. Your specific concerns relating to the
flood diversion through the I-405 box culvert in alternative 3 will be considered when the city
refines the flood control alternatives.
The specific change you suggest in Chapter 14, Capital Improvement Projects (page 95)
regarding the P-1 forebay has been incorporated into the text.
Art Madsen, Citizen Task Force
Thank you for your comments and support. The city of Renton looks forward to continuing to
work closely with you and other interested citizens as the recommendations of this plan are
implemented.
133
The recommended actions described in the Recommended Implementation Strategy section of
P gY
Chapter 16, Source Control Alternatives Strategy are consistent with several of your
suggestions. Action 8 would increase coordination with other jurisdictions; Actions 1, 3, 4, 5,
and 6 would locate upstream polluting sources in the basin; Action 2 would implement public
education and involvement; and Action 14 proposes various capital improvement programs.
Your suggestion regarding signage has been incorporated into the Recommended Program
discussion of the Ongoing Public Involvement and Education Programs section in Chapter 5,
Public Involvement and Education (page 27).
The Renton Parks Department included streamside trails in some locations in its city-wide trail
planning. The city will need to balance considerations of potential impact to wildlife and
potential educational benefits when determining whether a particular trail should be located
along a stream or wetland edge.
134