HomeMy WebLinkAboutEX_11_LUA21-000141_ExhibitsLocation Area (SF)Percent of
Total Site
Finished Product Storage 3,906 12.2%
Screening Area 3,025 9.4%
Curing Area 2,769 8.6%
Compost Bunker 2,202 6.9%
Biofilter 1,008 3.1%
Mixed Bunker 382 1.2%
Mixing Area 704 2.2%
Biosolids Bunker 1,020 3.2%
Bulk Material Bunker 2,087 6.5%
Pavement 11,223 34.9%
Other areas 3,801 11.8%
Total Site (WKL)32,127 100.0%
SITE AREA BY LOCATION
Figure 2. Paving and Site
Grading Plan
EXHIBIT 11
RECEIVED
Clark Close 04/19/2021
PLANNING DIVISION
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
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Project Location1200 Monster Rd SWRenton, WA 98057
Lake Washington
KentKent
RentonRenton
SeattleSeattle
SeaTacSeaTac
TukwilaTukwila
BurienBurien
BellevueBellevue
NewcastleNewcastle
DesDes
MoinesMoines
MercerMercer
IslandIsland
South Treatment Plant
Loop Compost Pilot ProjectFigure 1 - Vicinity/Location Map
The information included on this map has been compiled from a variety of sources and is
subject to change without notice. King County makes no representations or warranties,express or implied, as to accuracy, completeness, timeliness, or rights to the use of suchinformation. This document is not intended for use as a survey product. King Countyshall not be liable for any general, special, indirect, incidental, or consequential damages
including, but not limited to, lost revenues or lost profits resulting from the use or misue
of the information contained on this map. Any sale of this map or information on this mapis prohibited except by written permission of King County.
File Name: Q:\\WTD\Projects\Loop\Projects\STP_Biogas.mxd - Shari Cross
August 2019
200 0 200100
Feet
^_Loop Compost Pilot
South Treatment Plant
1 inch = 400 feet
See Figure 2 - Preliminary Site Plan for
the layout of the compost facilities.
EXHIBIT 3
RECEIVED
Clark Close 04/19/2021
PLANNING DIVISION
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
9,028 752
Loop Compost Pilot Project Neighborhood Detail Map
This map is a user generated static output from an Internet mapping site and
is for reference only. Data layers that appear on this map may or may not be
accurate, current, or otherwise reliable.
1/19/2021
Legend
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THIS MAP IS NOT TO BE USED FOR NAVIGATION
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WGS_1984_Web_Mercator_Auxiliary_Sphere
City and County Labels
City and County Boundary
Parcels
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RC-Resource Conservation
R1-Residential 1 du/ac
R4-Residential 4 du/ac
R6-Residential - 6 DU/AC
R8-Residential 8 du/ac
R10-Residential 10 du/ac
R14-Residential 14 du/ac
RMF-Residential Multi-Family
RMH-Residential Manufactured Homes
CN-Commercial Neighborhood
CV-Center Village
CA-Commercial Arterial
UC-Urban Center
CD-Center Downtown
COR-Commercial Office/Residential
CO-Commercial Office
IL-Industrial - Light
IM-Industrial - Medium
IH-Industrial - Heavy
Streets
Parks
Waterbodies
EXHIBIT 4
RECEIVED
Clark Close 04/19/2021
PLANNING DIVISION
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Department of Natural Resources and Parks ● Wastewater Treatment Division
Environmental Services ● 201 S Jackson Street, MS KSC-NR-5500
Seattle, WA 98104-3855
DETERMINATION OF NONSIGNIFICANCE
TITLE OF PROPOSAL: Loop® Compost Pilot Project at South Treatment Plant
DESCRIPTION OF PROPOSAL: The King County Wastewater Treatment Division proposes to construct a temporary pilot composting
system at King County’s South Treatment Plant (STP) which will further process Class B Loop® biosolids – a product of the wastewater
treatment process – into a Class A Loop compost. The regulatory designation of Class A biosolids allows for unrestricted use as a soil
amendment. The composting system will be built and operated within the boundaries of the County’s South Treatment Plant in Renton,
WA The project will operate for three to five years, after which it will be decommissioned.
LOCATION OF PROPOSAL, INCLUDING STREET ADDRESS, IF ANY:. The proposed project will be located in Renton WA, at
1200 Monster Road SW, within the existing STP site.
SEPA Responsible Official: Mark Isaacson
Position/Title: Director, King County Wastewater Treatment Division
Address: 201 S Jackson Street, MS KSC-NR-5500 Seattle, WA 98104-3855
Date: Signature:
Proponent and Lead Agency: King County Department of Natural Resources and Parks Wastewater Treatment Division
Contact Person: Jacob Sheppard, Environmental Planner
King County Wastewater Treatment Division 201 S Jackson Street, MS KSC-NR-5500 Seattle, WA 98104 phone: (206) 477-5395; e-mail: jacob.sheppard@kingcounty.gov
Issue Date: January 15, 2021 The State Environmental Policy Act (SEPA) lead agency for this proposal has determined that it does not have a probable significant adverse impact on the environment. An environmental impact statement is not required under RCW 43.21C.030(2)(c). This decision was made after review of a completed environmental checklist, the environmental reports listed in Section A.8 of the environmental checklist,
and other information on file with the lead agency. This information is available to the public on request.
This Determination of Nonsignificance (DNS) is issued under WAC 197-11-340 (2); the lead agency will not act on this proposal for 18 days from the issue date. Comments must be submitted by February 1, 2021. Submit comments to Katherine Fischer, Supervisor, Environmental Services, King County Wastewater Treatment Division, 201 S Jackson Street, MS KSC-NR-5500, Seattle, WA 98104-3855. Contact Jacob Sheppard, Environmental Planner, at (206) 477-5395 or jacob.sheppard@kingcounty.gov for questions or information
on how to submit comments electronically.
The King County Wastewater Treatment Division recently submitted a permit application for this project to the Puget Sound Clean Air Agency, which provides the opportunity for appeal. Therefore, there is no administrative appeal of this DNS pursuant to RCW 43.21C.075,
WAC 197-11-680, KCC 20.44.120, and King County Public Rule 7-4-1. The public rule may be viewed at
http://www.kingcounty.gov/about/policies/rules/utilities/put741pr.aspx or contact Jacob Sheppard, Environmental Planner, at (206) 477-
5395 or jacob.sheppard@kingcounty.gov to obtain a copy of the rule.
[Statutory authority: RCW 43.21C.110. 84-05-020 (Order DE 83-39), §197-11-970, filed 2/10/84, effective 4/4/84.]
aocupign Envelope fa: 4N92BB4P-0R0B-4ATR-BaB4-E0TENaSR9CAP
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EXHIBIT 5
RECEIVED
Clark Close 04/19/2021
PLANNING DIVISION
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Department of Natural Resources and Parks
Wastewater Treatment Division King Street Center, KSC-NR-0505 201 South Jackson Street Seattle, WA 98104
Environmental Checklist for Loop® Compost Pilot Project at South Treatment Plant
December 23, 2020
Prepared in compliance with the State Environmental Policy Act (SEPA) (RCW 43.21C), the SEPA Rules (WAC 197-11), and Chapter 20.44 King County Code, implementing SEPA in King County procedures.
This information is available in accessible formats upon request at
(206) 477-5371 (voice) or 711 (TTY).
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ENVIRONMENTAL CHECKLIST A. BACKGROUND 1. Name of proposed project, if applicable: Loop® Compost Pilot Project at South Treatment Plant 2. Name of applicant: King County Department of Natural Resources and Parks Wastewater Treatment Division 3. Address and phone number of applicant and contact person: King County Department of Natural Resources and Parks Wastewater Treatment Division Environmental Services Unit
KSC-NR-0505 201 S. Jackson Street Seattle, WA 98104 CONTACT: Jacob Sheppard, Environmental Planner
Phone: (206) 477-5395 Email: jacob.sheppard@kingcounty.gov 4. Date checklist prepared:
December 23, 2020 5. Agency requesting checklist:
King County Department of Natural Resources and Parks
Wastewater Treatment Division 6. Proposed timing or schedule (including phasing, if applicable):
Project construction is scheduled to occur in 2022. The proposed pilot-scale
composting facility is temporary, with an expected operation period of approximately five years, or according to the term of its temporary land use permit from the City of Renton.
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7. Do you have any plans for future additions, expansions, or further activity related to or connected with this proposal? If yes, explain.
Once operational, information from the project will be used to demonstrate proof of concept and develop a business case for composting, develop reliable sources of feedstocks and bulking agents, conduct product and process optimization, develop markets and distribution channels, build community support and collect data to inform the capital project process for a potential larger, permanent facility which would be
located off-site. Such a facility would be subject to a separate SEPA process in the future. 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal.
• Dispersion Modeling Protocol, King County South Treatment Plant Loop Compost Pilot Project. Prepared by Jacobs Engineering and HDR Engineering on behalf of King County Wastewater Treatment Division (2020). W3X90702
[Technical Memorandum]. 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain.
None known 10. List any government approvals or permits that will be needed for your proposal, if known.
City of Renton
• Temporary Use Permit
• Grading Permit
Puget Sound Clear Air Agency (PSCAA)
• Notice of Construction
Washington Department of Ecology (Ecology)
• Certificate of Compliance 11. Give brief, complete description of your proposal, including the proposed uses
and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. King County proposes to construct a temporary pilot composting system at King
County’s South Treatment Plant (STP) which will further process Class B Loop®
biosolids into a Class A Loop compost. The facility is designed to demonstrate the
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practicability of composting of Class B Loop biosolids mixed with bulking agents, such as wood chips and yard clippings, at various ratios to produce Class A biosolids. The proposed pilot project will enable the County to demonstrate the business case for
a full-scale Loop composting facility and evaluate various blends of feedstock to determine the optimal conditions for proceeding into a full-scale facility. This project is the first step to address a current lack of redundancy in the County’s biosolids program. The project will operate for three to five years, after which it will be decommissioned.
Approximately 0.91 acres will be used for the project. The project will have no permanent above ground structures. Biosolids are a soil amendment (a natural soil conditioner and fertilizer replacement)
that are made by cleaning the water that arrives at County wastewater treatment plants (WWTPs). The County’s biosolids, which are branded as “Loop,” are Class B, which have some detectable pathogens and therefore restrictions for use. At the WWTPs, the County’s anaerobic digester tanks use naturally occurring bacteria and other microorganisms to break down the waste and kill disease-causing pathogens. These
microorganisms transform the solids into a renewable, nutrient-rich, fully digested resource called biosolids. Most biosolids are used directly on farms and forests to improve crop yield and soil health. But Class B biosolids can also be mixed with bulking material such as yard clippings and wood chips and processed further into a compost. Biosolids compost has a Class A regulatory designation from the
Washington State Department of Ecology (Ecology), which allows for unrestricted use, just like any other retail garden product. Loop is used directly on farms and forests, with 25 percent applied to western
Washington forests and 75 percent transported and applied to eastern Washington
farms. However, transport of Loop can be suspended by road conditions on the Cascade mountain passes, which results in a rapid backlog of trucks filled with biosolids, especially in winter. The County has limited emergency storage options. The County is looking into composting as a local alternative for recycling Loop
because it would provide distribution options during inclement winter weather as well
as generate a useful local soil amendment with a low energy input requirement. The completed facility will employ a covered aerated static pile (CASP) technology using a bunker-style primary composting operation to fit within the limited available
area at STP. The proposed facility will be configured with a series of functional areas,
each equipped to perform the function of a full-scale compost facility. The functional areas include areas for receipt, mixing, composting, curing, and screening. Each functional area will be encircled with interlocking stacked concrete blocks that provide a confining barrier, or bunker, to the respective contents of each area. Some of the
bunkers may be covered by an open-sided fabric structure that is not fully enclosed but
is intended to protect the bunkers from rainfall. The active composting and curing areas are anticipated to have three blowers in nearly constant operation.
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The facility will function in a series of batches based on the amount of material received from the delivery of a single truckload of Loop from one of the County’s treatment plants. The facility will be equipped to receive up to one truck per week but
could receive material less frequently, if desired. Each Loop delivery will initiate a two-month-long process. Mixing of biosolids with bulking material will occur immediately upon receipt of a load of biosolids, directly followed by placement of the mixed material into an active composting bunker. This is intended to occur on the same day as receipt. Doing so will reduce the propensity of odorous emissions. The
mixer will be powered by electricity. Active composting will last 28 days per batch. Curing, which will occur after active composting, will last an additional 28 days. Once curing is complete, the compost will be screened using a trommel to remove large-diameter material from the finished product. The finished product area will be sized to accommodate approximately 400 cubic yards of material, or approximately four to
seven batches of processed material depending on the bulking ratio employed. During the active composting and curing processes, temperature will be managed by forced aeration. The aeration system will run according to a system of temperature sensors and programmable controls for optimal process conditions and odor control,
according to desired testing parameters, industry standards and best management practices. The aeration system is automatically reversing, drawing cool air into the compost piles either from the top or bottom. The negative aeration process will draw air from beneath the pile, into air ducts placed on-grade beneath the pile, and out to a manifold directing the collected air to an odor-scrubbing biofilter. The positive
aeration process will draw cool air into the fan and push it into the plenum on the floor and up through the pile, which is covered by a biolayer of finished compost or wood chips for odor and temperature control.
Material will be moved between functional areas using a front-end loader. 12. Location of the proposal. Give sufficient information for a person to understand the precise location of your proposed project, including a street address, if any, and section, township, and range, if known. If a proposal would occur over a
range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applications related to this checklist.
The proposed project is located in Renton WA, at 1200 Monster Road SW. The project will occupy King County Parcel Numbers 2423049097 and 2423049006, which are located in NE Quarter-Section, Section 24, Township 23 North, Range 9 East.
The project is located on the STP property. See Figure 1 below.
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Figure 1. Site and vicinity map
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B. ENVIRONMENTAL ELEMENTS 1. Earth a. General description of the site
(circle one): Flat, rolling, hilly, steep slopes, mountainous, other __________.
b. What is the steepest slope on the site? (approximate percent slope)? The steepest slopes on the site are approximately 25%.
c. What general types of soils are found on the site? (for example, clay, sand, gravel, peat, muck)? If you know the classification of agricultural soils, specify them and note any agricultural land of long-term commercial significance and whether the proposal results in removing any of these soils.
In general, the site overlies previous fill consisting of silty sand with gravel to a
depth of approximately 25 feet. The fill layer is underlain by native sand, silt, and gravel to a depth of approximately 80 feet. Neither the project site nor its surroundings contain agricultural land of long-
term commercial significance. d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe.
No.
e. Describe the purpose, type, total area, and approximate quantities and total affected area of any filling, excavation, and grading proposed. Indicate source of fill.
The project will occupy approximately 0.91 acre of the approximately 72-acre STP property. Minor grading will be required. Minor excavation will be required, including for shallow trenches that will be cut and filled in order to install utility lines on the site. Subsequent backfill will consist of native soil to
the greatest extent possible, supplemented by clean fill when required by permit
conditions or engineering specifications. f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe.
Some localized erosion could occur during clearing and construction. However, erosion control measures will be used to minimize the potential for this to occur. See Section B.1.h below for typical Best Management Practices (BMPs) and
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other measures that could be utilized to minimize the potential for erosion. Erosion is not expected to occur as a result of the completed facility. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? The project site is currently composed entirely of impervious surfaces, and will remain so after project construction.
h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: Temporary erosion and sedimentation control measures will be employed
throughout project construction, including prior to all clearing, excavation, filling, grading, and other soil-disturbing activities in the project area. These control measures will be identified in the project plans and construction specifications and will be implemented as required by the City of Renton, Ecology, and other permitting agencies.
Typical measures that may be used include installing filter fabric fences and other sediment barriers, placing silt traps in storm drain inlets, covering soil stockpiles and exposed soils, and using settling facilities to prevent sediment from leaving the site.
Additional best management practices (BMPs) and other measures could include the following:
• Designation of personnel to inspect and maintain temporary erosion and
sediment control measures
• Use of appropriate means such as stabilized entrances and wheel washes to minimize tracking of sediment onto roadways by construction vehicles
• Regular street cleaning for mud and dust control
• Disposing of excess excavated soil at an approved disposal site as soon as practical
• Restoration of disturbed areas by repaving or replanting as soon as
practical after construction is completed 2. Air a. What types of emissions to the air would result from the proposal during
construction, operation, and maintenance when the project is completed? If any, generally describe and give approximate quantities if known. Project construction will involve temporary, mobile source air emissions (NOx, VOC, CO, PM10, PM2.5), including diesel exhaust from construction
equipment and dust generated by earth-moving activities. The exhaust emissions
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will be intermittent and spread across the project area. They are not expected to affect attainment of air quality standards in the project area.
Potential emissions from the composting operations include odors, volatile organic compounds (VOCs), hazardous air pollutants (HAPs) and toxic air pollutants (TAPs), greenhouse gases (GHG), and fugitive dust which includes particulate matter with diameter <10 micrometers (PM10) and particulate matter with diameter <2.5 micrometers (PM2.5). There will be minor emissions of
nitrogen oxides (NOx), carbon monoxide (CO) and sulfur dioxide (SO2) from the combustion of diesel in a 38 kW (51 Hp) diesel engine used to power the trommel screen. The trommel screen is expected to operate for less than four hours each week. Front-end loader operations and material deliveries will also generate occasional minor diesel exhaust emissions.
The facility will go through new source review (NSR) with the local permitting authority, the Puget Sound Clean Air Agency (PSCAA). As part of NSR, the County will submit a Notice of Construction (NOC) application and receive an Order of Approval issued by PSCAA under PSCAA Regulation I, Article 6 prior
to commencement of construction. To minimize emissions and comply with all state and local emission standards, the process will use Best Available Control Technology (BACT) and BACT for TAPs (tBACT). Facilities submitting a NOC application are also required to complete a review
of the air quality impacts from TAPs to demonstrate that the proposed project does not have the potential to adversely affect the health of people in the surrounding community. Washington Administrative Code (WAC) 173-460-150 lists the regulated TAPs along with their respective averaging period, acceptable
source impact level (ASIL), small quantity emission rates (SQER), and de
minimis emission values. Potential emissions of VOC, PM10 and PM2.5 are estimated to be below NSR exemption levels (2.0 tons per year, 0.75 ton per year, and 0.5 ton per year
respectively) per WAC 173-400-110(5)(a)(i). Of the 33 TAPs identified as being
potential emissions from the facility, 11 exceeded their de minimis thresholds. The de minimis values are defined as the maximum level of emissions that do not pose a threat to human health or the environment. If emissions of a given TAP from a source do not exceed the associated de minimis emission values,
then that TAP is exempt from further NSR evaluation.
None of the TAPs exceeded their SQER, so dispersion modeling of TAP emissions is not required to demonstrate compliance with the ASIL. See Table 1 for a summary of emissions from facility operations, and Appendix A for King
County greenhouse gas emissions worksheets.
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Table 1. Emissions summary Pollutant Potential Emissions
Odors 52,808 OU/min
Volatile organic compounds (VOCs) 347 lb/year
Hazardous and toxic air pollutants (HAPs and TAPs) 1,421 lb/year
Particulate matter with a diameter <10 micrometers (PM10) 3.1 lb/year
Particulate matter with a diameter <2.5 micrometers (PM2.5) 0.5 lb/year
Nitrogen oxides (NOx) 78 lb/year
Carbon monoxide (CO) 87 lb/year
Sulfur dioxide (SO2) 0.02 lb/year
Greenhouse Gases (GHG) 2,820 lb/year CO2eq
Notes: OU/min = odor units per minute lb/year = pounds per year
b. Are there any off-site sources of emissions or odor that may affect your
proposal? If so, generally describe.
There are no known off-site sources of air emissions or odors that may affect the project.
c. Proposed measures to reduce or control emissions or other impacts to air, if any: During construction, BMPs will be implemented to control dust. Types of BMPs that will be used may include street sweeping, watering exposed soil surfaces,
and covering soil stockpiles to help minimize the amount of fugitive dust and
particulate pollution to the surrounding areas. Construction equipment-related emissions will be reduced by requiring proper maintenance of equipment, using electrically-powered equipment where practical, and avoiding prolonged idling of vehicles and equipment.
To minimize emissions during operation and comply with all state and local emission standards, the process will use BACT and tBACT. In addition, a biofilter will be operated and maintained according to recommendations provided by industry experts, in order to minimize odors. Odor management is
vital to the success of a compost facility. No compost facility is expected to be
odor free. However, WAC 173-350-040 requires the facility to not violate the regulating air authority’s emission standards or ambient air quality standards at the property boundary.
Composting is an aerobic process; when the process lacks sufficient oxygen it
can be classified as hypoxic or anoxic. In the hypoxic or anoxic states, odorous volatile compounds are produced including alcohols, acids, H2S, and NH3. Maintaining aerobic conditions requires management of oxygen content and temperature in the compost piles. Aeration to manage temperature – keeping
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piles uniform in temperature and cooler than 65 degrees Celsius – will also provide sufficient fresh air to stay well above the threshold of 2 parts per million of oxygen required to maintain aerobic conditions. The facility’s aeration
equipment will be designed and operated to provide a constant, uniform aeration capacity of 5 cubic feet per minute per cubic yard of material. Process air from the active composting and curing areas will be direct through a biofilter, which will scrub volatile organic compounds (VOCs) and odorous air
contaminants. The biofilter will be oversized compared to industry standards and will provide an empty-bed retention time (the average time process air will spend getting through the volume occupied by the biofilter material) of 75 seconds, whereas the industry standard is 60 seconds.
Air quality modeling indicates that additional detectable odors beyond the STP property line will be very infrequent, of short duration, and unlikely to be discernable from other odors in the area. 3. Water a. Surface Water: 1) Is there any surface water body on or in the immediate vicinity of the site (including year-round and seasonal streams, saltwater, lakes, ponds, or wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. Springbrook Creek, a Type S water (shoreline of the state), is located east
of STP. Waterworks Gardens, located north of the project site across an
access road, is a complex of connected wetponds and a Category II wetland that provides stormwater detention and treatment for much of the STP property, and outlets into Springbrook Creek.
2) Will the project require any work over, in, or adjacent to (within 200 feet) the described waters? If yes, please describe and attach available plans. The project will not require any work over, in, or within 200 feet of water
bodies.
3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material.
No fill or dredge material will be placed in or removed from surface waters or wetlands.
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4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities if known.
The project will not require surface water withdrawals or diversions. 5) Does the proposal lie within a 100-year floodplain? If so, note location on the site plan.
The project does not lie within a 100-year floodplain. 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. The project will not involve any discharges of waste materials to surface waters. b. Ground Water: 1) Will ground water be withdrawn, from a well for drinking water or other purposes? If so, give a general description of the well, proposed uses, and approximate quantities withdrawn from the well. Will water be discharged to ground water? Give general description, purpose, and approximate quantities if known. No groundwater will be withdrawn as part of the project, and no water will
be discharged to groundwater.
2) Describe waste material that will be discharged into the ground from septic tanks or other sources, if any (for example: Domestic sewage; industrial, containing the following chemicals...; agricultural; etc.).
Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve. No waste material related to the project will be discharged into the ground
from septic tanks or other sources.
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c. Water Runoff (including storm water): 1) Describe source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe. At present, the surface water in the project area flows into STP’s
stormwater conveyance and treatment system, which includes multiple biofiltration swales, catch basins, pipes, a large pump station, and a series of wetponds and wetlands in Waterworks Gardens. During construction, the primary source of water runoff onto and off of
work areas will be stormwater. Stormwater drainage patterns may be altered during construction due to surface alterations. Stormwater runoff during construction will be managed to prevent runoff from leaving the site using storm water BMPs such as those described below in Section B.3.d.
When the project is completed, stormwater from the project site will be collected and routed to the wastewater influent stream at STP. Stormwater flow in the vicinity will not be affected. 2) Could waste materials enter ground or surface waters? If so, generally describe. During construction, the County will implement BMPs to prevent
introduction of potential contaminants into ground and surface waters,
which could include:
• Storing fuels and other potential contaminants in secured containment areas
• Containing equipment, materials, and wash water associated with
construction
• Conducting regular inspections, maintenance, and repairs of fuel hoses, hydraulically operated equipment, lubrication equipment, and
chemical/petroleum storage containers
• Maintaining spill containment and clean up material at the construction site
• Establishing a communication protocol for handling spills
After the facility is completed, runoff will be contained on-site and prevented from entering local water bodies prior to treatment.
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3) Does the proposal alter or otherwise affect drainage patterns in the vicinity of the site? If so, describe.
The project will not alter drainage patterns in the vicinity of the site. d. Proposed measures to reduce or control surface, ground, and runoff water, and drainage pattern impacts, if any:
Stormwater management during and after construction will comply with all applicable permits and government approvals, including requirements and guidelines from the City of Renton, King County, and Ecology. In particular, King County will meet performance standards included within the 2017 City of Renton Surface Water Manual and City Amendments. Stormwater management
BMPs will be used during construction to control stormwater runoff. Examples of typical BMPs that could be used during construction are presented in Section B.1.h above. The completed facility will include stormwater containment measures to direct
runoff to the wastewater influent stream at STP. 4. Plants a. Check or circle types of vegetation found on the site:
deciduous tree: alder, maple, aspen, other: ash, sweet gum, crabapple, pear, cottonwood
evergreen tree: fir, cedar, pine, other: Norway spruce
shrubs: salal, Oregon grape
grass
pasture crop or grain orchards, vineyards, or other permanent crops wet soil plants: cattail, buttercup, bulrush, skunk cabbage, other
water plants: water lily, eelgrass, milfoil, other types of vegetation
b. What kind and amount of vegetation will be removed or altered? The project site currently contains landscaping that will need to be removed. Plants to be removed include 13 ornamental cedar trees.
c. List threatened or endangered species known to be on or near the site. There are no threatened or endangered plants known to be on or near the site.
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d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any:
No landscaping is currently proposed as part of the project. e. List all noxious weeds and invasive species known to be on or near the site. No noxious weeds are known to be located on the site. However, tansy ragwort
and spotted knapweed have been documented on neighboring parcels. Invasives on the project site are limited to sporadic, herbaceous species. 5. Animals a. List any birds and other animals which have been observed on or near the site or are known to be on or near the site. The project site does not include significant habitat for birds or mammals, although small mammals and some urban-adapted bird species are expected to
occur in the general area and at the site. Washington Department of Fish and Wildlife’s Priority Habitats and Species list does not list priority species on the site. However, the Black River Riparian Forest, just north of the treatment plant property, contains the largest document great blue heron rookery in the Puget Sound Region. The Black River wetlands and Springbrook Creek also provide
habitat numerous other waterfowl species, as well as a variety of fish species (Chinook, coho, resident coastal cutthroat, steelhead, and winter steelhead). b. List any threatened or endangered species known to be on or near the site.
Chinook and steelhead are federally-listed, threatened species that occur in the Springbrook Creek segment of the Black River, which is also federally-designated as critical habitat.
c. Is the site part of a migration route? If so, explain.
The project site is within the Pacific Flyway avian migration route. d. Proposed measures to preserve or enhance wildlife, if any:
Impacts to wildlife are not anticipated as a result of this proposal; therefore, no special measures to preserve wildlife are proposed. e. List any invasive animal species known to be on or near the site.
None known
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6. Energy and Natural Resources a. What kinds of energy (electric, natural gas, oil, woodstove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. The completed facility will use electricity to operate the mixer, and aeration system. The front-end loader and mobile trommel will be diesel-powered.
b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. The completed facility will not affect the potential use of solar energy by
adjacent properties. c. What kind of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any:
Blower fans will be equipped with variable speed motors to save energy when less aeration is needed. 7. Environmental Health a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe.
1) Describe any known or possible contamination at the site from present or past uses. The STP site was developed in 1965 as a wastewater treatment facility,
and prior, was undeveloped land. There are five leaking underground
storage tanks (LUSTs) located within the vicinity of the project site, but none are located in the project area and there is no confirmed groundwater contamination associated with the LUSTs.
2) Describe existing hazardous chemicals/conditions that might affect project development and design. This includes underground hazardous liquid and gas transmission pipelines located within the project area and in the vicinity.
There are no hazardous chemicals or conditions in the vicinity that might
affect project development or design.
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3) Describe any toxic or hazardous chemicals that might be stored, used, or produced during the project's development or construction, or at any time during the operating life of the project. Construction-related materials such as fuel and hydraulic fluid will be stored and used on site during construction. BMPs will be implemented during construction to minimize the potential for spills or mechanical failures to occur, and to minimize the potential for adverse effects from
hazardous chemicals to workers or nearby residents. The completed facility will process Class B biosolids, which may contain low levels of pathogens. These pathogens do not pose a risk to human health unless ingested. The composting process will reduce or eliminate
these pathogens from the finished product. 4) Describe special emergency services that might be required. None anticipated
5) Proposed measures to reduce or control environmental health hazards, if any: As described in items B.1.h and B.3.d. above, BMPs and other measures
will be used to avoid or contain and control any accidental spills or releases of hazardous materials during project construction. Project plans and construction specifications include measures to safely handle and dispose of contaminated materials. No sources of contaminated materials
are known to be on the project site. However, if unexpectedly encountered
during construction, contaminated materials will be removed from the work area and transported to a permitted disposal site. The contractor will prepare a health and safety plan as a deliverable for the proposed project prior to the start of construction. This plan will comply with all applicable
health regulations and will detail measures to control environmental health
hazards. The composting process generates enough heat that combustion is possible if temperature is not managed effectively. The facility will operate using
industry best practices to maintain an appropriate and safe temperature in
the compost piles. Facility staff will adhere to the same environmental safety requirements and guidelines, prescribed by King County, as the rest of the STP facility.
These requirements and guidelines include BMPs for the proper handling
of Class B biosolids, as well as BMPs for storage, handling, disposal, and clean-up of hazardous materials.
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b. Noise 1) What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? Noise in the project area will not affect the project. 2) What types and levels of noise would be created by or associated with the project on a short-term or a long-term basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come from the site. Construction noise may exceed existing background noise levels at times.
Noise levels will vary depending on the specific equipment used for particular activities. Based on previous construction projects, typical noise levels can be expected to range from about 70 to 90 dBA measured at a distance of 50 feet from the source. Throughout project construction, short-term, intermittent construction related noise may include engine and
mechanical equipment noises associated with the use of heavy equipment such as bulldozers, excavators, cranes, haul trucks, generators, chainsaws, and air compressors. Construction-related noises will be limited to construction hours allowable
by the City of Renton’s noise control code. If work outside of daytime working hours is required, an application for a variance will be submitted to the City of Renton.
In the completed facility, mechanical equipment will generate noise during
the day and night. None of the noises generated on the completed facility will exceed the City of Renton’s maximum permissible sound level for the site’s zoning or that of nearby receiving sites.
3) Proposed measures to reduce or control noise impacts, if any:
All construction and facility operation activities will be consistent with the City of Renton noise control code. All impacts from noise generated by construction will be short-term and temporary in nature. Construction
BMPs will be used to minimize construction noise and could include:
• Using effective vehicle mufflers, engine intake silencers, and engine enclosures, and shutting off equipment when not in use
• Using temporary noise barriers around stationary equipment
• Positioning noise-generating equipment in the project area so that it is as far away as possible from sensitive receptors
• Notifying residents and businesses near the project site of upcoming
noisy construction activities
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• 24-hour construction hotline to promptly respond to questions and complaints
Sound generated by facility operations will be attenuated and muffled by vegetation and the distance to receptors. Because the maximum predicted acoustical level of noise at the property line of adjacent properties is below code limits, no additional mitigation is proposed.
8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? Will the proposal affect current land uses on nearby or adjacent properties? If so, describe. The site is currently occupied by King County’s South Treatment Plant. Adjacent properties include commercial and industrial sites. The proposed project will not affect current land uses on adjacent or nearby properties.
b. Has the project site been used as working farmlands or working forest lands? If so, describe. How much agricultural or forest land of long-term commercial significance will be converted to other uses as a result of the proposal, if any? If resource lands have not been designated, how many acres in farmland or forest land tax status will be converted to nonfarm or nonforest use? Historic aerial photographs suggest the project area was part of a farm between the late 1930s and late 1950s. The site has not been used as agricultural land
since that time, and is not designated as agricultural land of long-term commercial significance. The project will not result in conversion of farm or forest land to a nonfarm or nonforest use. 1) Will the proposal affect or be affected by surrounding working farm or forest land normal business operations, such as oversize equipment access, the application of pesticides, tilling, and harvesting? If so, how: No.
c. Describe any structures on the site. The area of STP that contains the project site currently includes numerous industrial buildings associated with wastewater treatment, administrative
buildings, and access roads.
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d. Will any structures be demolished? If so, what? No.
e. What is the current zoning classification of the site? Industrial Heavy (IH) f. What is the current comprehensive plan designation of the site? The site is located within the designated Employment Area (EA). g. If applicable, what is the current shoreline master program designation of the site? The proposed project will occur outside of the shoreline zone. h. Has any part of the site been classified as a critical area by the city or county? If so, specify. The project site is within two City of Renton-designated geologic hazard areas: a moderate Coal Mine Hazard Area and a high Seismic Hazard Area. i. Approximately how many people would reside or work in the completed project? Approximately 140 people currently work at STP. The proposed facility will not
result in additional staff being employed.
j. Approximately how many people would the completed project displace? None
k. Proposed measures to avoid or reduce displacement impacts, if any: None
l. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: Construction of the project will not conflict with existing land use plans and policies; however, a number of permits or approvals will be required. The City
of Renton is being consulted to ensure that the project is compatible with
existing and projected land uses and plans.
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The City of Renton anticipates that the surrounding area will continue to be used for commercial and light industrial uses during the temporary duration of the project. Therefore, the completed facility is not expected to be incompatible
with existing or future land use plans for the area. m. Proposed measures to ensure the proposal is compatible with nearby agricultural and forest lands of long-term commercial significance, if any:
None 9. Housing a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low-income housing. None b. Approximately how many units, if any, would be eliminated? Indicate whether high, middle, or low-income housing. None c. Proposed measures to reduce or control housing impacts, if any:
None 10. Aesthetics
a. What is the tallest height of any proposed structure(s), not including antennae; what is the principal exterior building material(s) proposed? Temporary structures for the project will be no higher than approximately one
story. Exterior building materials will include asphalt, concrete blocks, and
fabric overhead coverings. b. What views in the immediate vicinity would be altered or obstructed?
Views of the site will remain generally the same. The size of the overall Plant
will not change and character of the site will continue to be that of an industrial operation, and the project site will not be visible from outside of the Plant property.
c. Proposed measures to reduce or control aesthetic impacts, if any:
There are no measures proposed to address aesthetic impacts of the project.
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11. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? Project construction will take place largely during daylight hours. Temporary site lighting may be used at the beginning and end of work days during construction when daylight hours are short.
The completed project will require sufficient light for safety and security, similar in nature to the existing STP site. Outside areas that are currently lit at night at STP include entry and exit driveways, truck staging and parking areas, and building entrances.
b. Could light and glare from the finished project be a safety hazard or interfere with views? No. The site is surrounded by buildings to the west, east, and south with similar
exterior lighting. c. What existing off-site sources of light or glare may affect your proposal? None
d. Proposed measures to reduce or control light and glare impacts, if any: All exterior lights will be focused or shielded as necessary to cast light only in
areas that require it and to minimize light spilling onto neighboring properties.
12. Recreation a. What designated and informal recreational opportunities are in the
immediate vicinity?
Waterworks Gardens is a King County-owned eight-acre park located north of the project area. The main feature of the gardens are wetlands established to provide storm water treatment for STP.
Other recreational opportunities in the general vicinity include Springbrook Trail, a 2.3-mile trail that parallels the eastern boundary of the 50-acre STP site until it crosses Oakesdale Ave SW and enters the Black River Riparian Forest and Wetland. The Black River Riparian Forest is a 93-acre refuge that is popular
for birdwatching.
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b. Would the proposed project displace any existing recreational uses? If so, describe.
No. c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any:
None 13. Historic and Cultural Preservation a. Are there any buildings, structures, or sites, located on or near the site that are over 45 years old listed in or eligible for listing in national, state, or local preservation registers located on or near the site? If so, specifically describe. No buildings, structures, or sites that are listed in or eligible for listing in
preservation registers have been identified on the project site, or within 0.5 miles of the project site. Two unevaluated historic properties are within or adjacent to the project site. The first is South Treatment Plant itself, described as “Renton Sewage
Treatment Plant” in the Washington Department of Archaeology and Historic Preservation (DAHP) database, which was constructed in 1965, and is therefore over 45 years old. South Treatment Plant was recorded on a DAHP Historic Property Inventory form in 2010, but no determination has been made regarding
eligibility for listing in the National Register of Historic Places (NRHP). An
update to this inventory form may be required by DAHP. The second unevaluated historic property is the Graphic Packaging International factory, located adjacent to STP at 601 Monster Road SW. The building, constructed in 1956, was recorded in the Historic Property Inventory as part of an import of
county assessor data, but no recommendation has been made regarding its
eligibility for listing in the NRHP. However, that building is outside of the view-shed of the project, and no impact is anticipated. b. Are there any landmarks, features, or other evidence of Indian or historic
use or occupation? This may include human burials or old cemeteries. Are there any material evidence, artifacts, or areas of cultural importance on or near the site? Please list any professional studies conducted at the site to identify such resources.
Numerous cultural resources investigations have been conducted in the recent
past associated with construction projects at STP. No landmarks, features, or other evidence of Indian or historic use have been identified on the project site during these investigations; however, there are several nearby sites, including
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precontact- and historic-era sites. Historic resources are railroad grades and historic debris scatters. Precontact resources are village sites, including sites where human burials have been identified. Three of the village sites have been
determined eligible for listing on the NRHP. Based on proximity of the project site to recorded archaeological sites, its location above the former Black River channel and near the confluence with the Green (White) River, and the presence of ethnographic sites within the vicinity, it is likely that people used the landforms contained within the project area during the precontact and
ethnographic periods. However, due to the previous development of STP, which involved large-scale earth work, the likelihood for intact archaeological sites is diminished. c. Describe the methods used to assess the potential impacts to cultural and historic resources on or near the project site. Examples include consultation with tribes and the department of archeology and historic preservation, archaeological surveys, historic maps, GIS data, etc. The project was screened by the King County Historic Preservation Program for
the presence of cultural and historic resources within the project area and the probability of an inadvertent discovery of cultural resources during project construction. This screening included a review of historic registers, databases including the DAHP records database (“WISAARD”), historic maps and reports, and predictive GIS modeling. Environmental Science Associates also
conducted an in-depth review of existing cultural resources reports and databases. d. Proposed measures to avoid, minimize, or compensate for loss, changes to,
and disturbance to resources. Please include plans for the above and any permits that may be required. King County will prepare an inadvertent discovery plan (IDP) for project construction. The IDP will provide guidance to contractors for identifying
potential cultural resources, and establish procedures to follow in the event of
the unanticipated discovery of potential cultural resources in order to protect the discovery until it can be assessed by a professional archaeologist. 14. Transportation
a. Identify public streets and highways serving the site or affected geographic area, and describe proposed access to the existing street system. Show on site plans, if any.
The site is bordered by SW Grady Way and I-405 to the south, Oakesdale
Avenue SW to the east and north, and Monster Road SW to the west. The primary access to the northern portion of STP, where the project will be
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developed, is via SW 7th Street. However, there are additional driveways located off of Monster Road SW, Longacres Drive SW, and SW Grady Way. b. Is the site or affected geographic area currently served by public transit? If so, generally describe. If not, what is the approximate distance to the nearest transit stop? The 50-acre STP site is served by public transit. King County Metro stops for
the 161 and 280 are located on SW Grady Way and the Tukwila Station for Amtrak and the Sounder Train are located a mile to the south of STP. c. How many additional parking spaces would the completed project or non-project proposal have? How many would the project or proposal eliminate?
The completed project will not include additional parking spaces, nor will it eliminate any existing parking spaces. d. Will the proposal require any new or improvements to existing roads, streets, pedestrian, bicycle, or state transportation facilities, not including driveways? If so, generally describe (indicate whether public or private). No such improvements are included as part of this proposal. e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. No.
f. How many vehicular trips per day would be generated by the completed project or proposal? If known, indicate when peak volumes would occur and what percentage of the volume would be trucks (such as commercial and nonpassenger vehicles). What data or transportation models were used
to make these estimates?
Project construction will require the delivery of equipment and materials by truck, generating approximately 275 truck trips. Once complete, small amounts of wood chips and yard waste will be regularly transported on-site and finished
compost product will regularly be transported off-site. Given the existing
vehicular activity on the STP property, including daily biosolids hauling, and the industrial nature of the project vicinity, there will be negligible changes in vehicular traffic as a result of the project.
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g. Will the proposal interfere with, affect or be affected by the movement of agricultural and forest products on roads or streets in the area? If so, generally describe.
No. h. Proposed measures to reduce or control transportation impacts, if any:
Long-term transportation impacts are not anticipated; therefore, mitigation measures have not been developed. 15. Public Services a. Would the project result in an increased need for public services (for example: fire protection, police protection, public transit, health care, schools, other)? If so, generally describe. No.
b. Proposed measures to reduce or control direct impacts on public services, if any: None 16. Utilities a. Circle utilities currently available at the site:
electricity, natural gas, water, refuse service, telephone, sanitary sewer, septic system, other________ b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the
immediate vicinity which might be needed.
The project will primarily involve short extensions of the existing utilities located on site. Electric and natural gas service on the site is provided by Puget Sound Energy, water and refuse service is provided by City of Renton, and
wastewater service is provided by King County.
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C. SIGNATURE The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision.
Signature:
Katherine Fischer, Environmental Programs Managing Supervisor King County WTD
12/23/20 Date Submitted:
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Appendix A. King County greenhouse gas emissions worksheets Table A.1. Net project impact (metric tons of CO2)
Project or Tool Input Output Additional Calculations Final Output NET Project Impact a Energy MTCO2e Project Life (years) MTCO2e
Construction phase ‐ ‐ MTCO2e
Operations phase 123 5 614.82 686.10
b Water MTCO2e Project Life (years) MTCO2e
Construction phase ‐ ‐
Operations phase ‐ 0 ‐
c Transportation (VMT) MTCO2e
KC Employee Commute Climate Pollution Map Av MTCO2e # employees
‐ 0 ‐
KC Residential Transportation Climate Pollution Map
Av MTCO2e # households MTCO2e
‐ 0 ‐
d Embodied Energy MTCO2e MTCO2e
71 71.28
1 Waste Reduction Model (WARM) MTCO2e MTCO2e
‐ ‐
2 URBEMIS lbsCO2/day # project days MTCO2e
‐ 0 ‐
3 Roadway Construction Emissions Model tonsCO2/project MTCO2e
‐ ‐
4 Build Carbon Neutral MTCO2 MTCO2e
‐ ‐
5 Tree Carbon Calculator kgCO2 # trees MTCO2e
‐ 0 ‐
6 Reforestation Calculator MTCO2e MTCO2e
‐ ‐
*Beneficial use of Loop compost sequesters, or removes, CO2 from the atmosphere. This project will sequester an estimated 514 metric tons of CO2 over its duration, offsetting much of the emissions shown in this worksheet.
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Table A.2. Energy use (metric tons of CO2) Project Input Data Input Input Unit Output Additional Calculations Energy Use Construction Operations MTCO2e Project Life (years) enter in the amount of electricity or fuel used by project phase
Electricity 77,743 kWh 0 49.6311312 5
Gasoline1 gallons 0 0 Diesel1 5,876 gallons 0 73.33248 Natural Gas therms 0 0 Heating Oil gallons 0 0 Jet Fuel gallons 0 0 Steam Mlb 0 0 Propane gallons 0 0
Energy Use‐‐Biofuels Project Life (years)
Green Electricity2 51,829 kWh 0 0 Biogenic Sources3
Biodiesel1 gallons 0 0 Landfill gas or Biogas2 MMBtu 0 0
Project Input Data Input Input Unit Output
Vehicle Miles Traveled (VMT) MTCO2e Project Life (years) enter the estimated annual VMT for the project ‐ miles 0 0 0
Project Input Data Input Input Unit Output
Water Use ('watergy') MTCO2e Project Life (years) enter the amount of water used by project phase ‐ gallons 0 0 0
1. Lifecycle GHG Emissions (includes both combustion and fuel production)
2. Green electricity and biogas are considered carbon‐neutral energy sources; CO2e output is zero
3. Please separately calculate and note any biogenice sources of greenhouse gas emissions
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Table A.3. Embodied energy (metric tons of CO2) Project Input Data Input Input Unit Output
Materials Use MTCO2e
enter tons (US tons, or short tons) of material used
Concrete
Cement
Asphalt
648
US tons
US tons
US tons
0
0
71
Dimensional lumber
Glass
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Department of Natural Resources and Parks
Wastewater Treatment Division
King Street Center, KSC-NR-5500
201 South Jackson Street Seattle, WA 98104-3855
February 19, 2021
[via e-mail: vdolbee@rentonwa.gov] City of Renton Department of Community & Economic Development – Planning Division
1055 S Grady Way
Renton, WA 98057 Dear Ms. Dolbee,
Thank you for your comments on King County’s proposed Loop® Compost Pilot Project at South Treatment Plant. See below for responses to each of your comments and questions.
Comment 1: We request the following mitigation measure be added to the project: King
County should establish a complaint hotline, where odor complaints can be directed. If
complaints are received King County should immediately address the odor causing concerns and deploy additional odor reduction measures to reduce these off-site impacts. King County should notify the City of any complaint received and how they are addressing the complaint.
King County response: The project is located within the property boundary of King County’s South Treatment Plant (STP). The plant has a 24-hour odor control hotline which is (206) 263-1760. Details of STP’s odor complaint process can be found here:
https://www.kingcounty.gov/depts/dnrp/wtd/response/odor-control.aspx. Before compost operations commence, the Department of Ecology must approve the compost project’s operations plan, according to state biosolids regulations under WAC 173-308. The approved operations plan will address in detail how odor is controlled to mitigate off-site impacts, especially in the event of a complaint where the compost facility is determined to be the source
of the odor.
The County requests that upon submittal, the City of Renton review the temporary use permit application for this facility and evaluate if further discussion of mitigation is warranted at that
time.
EXHIBIT 6
RECEIVED
Clark Close 04/19/2021
PLANNING DIVISION
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Comment 2: Please clarify where compost will be disposed while seeking Class A status.
King County response: Aerated static pile composting, the technology used in this pilot project,
is an approved Class A “process to further reduce pathogens” under WAC 173-308-170(3). The WAC includes requirements for minimum temperature of piles and the minimum duration the temperature must be maintained, as well as a maximum density of Salmonella sp. bacteria. Ecology must issue a Final Approval of the County’s operations plan, which would confirm the
County’s proposed Class A classification, before the facility begins operating. During operations, the County will monitor temperature and pathogen density on an ongoing basis. If Class A requirements are not met, the County would follow the product quality contingency plan outlined in the project’s approved operations plan. While exact details are still
in development, the contingency plan will include at least two options: 1) re-mix and re-compost the batch to meet process requirements, or 2) land-apply the compost as Class B biosolids, according to the County’s existing Ecology-approved Class B procedures. Similar to existing biosolids management practices, if a compost batch were to fail to meet Class B biosolids
requirements, it would be landfilled.
Comment 3: The SEPA Checklist indicates that each batch can produce 400 cubic yards or more of compost. Truck trips associated with removal of the compost should be
disclosed and mitigated.
King County response: The compost facility will produce approximately 2,500-3,500 cubic yards of compost per year. The additional truck trips for the compost facility represent substantially less than 1% of STP’s total annual truck traffic and will not be discernably different from the
existing industrial activities and existing truck trips in the area. Biosolids make up only a portion of the activities and truck trips associated with STP, but for comparison, approximately 10 trucks leave STP per day to deliver Class B Loop biosolids to King County’s customers, for a total of 3,650 annual truck trips from STP’s distribution of Loop.
The proposed project will result in a decrease of approximately 26 truck trips per year of Loop biosolids that would otherwise be transported off-site, and an increase of approximately 150 truck trips per year for delivery of compost bulking agents, for a net increase of approximately 124 trips per year. Bulking agents will be delivered on average once per week, and trips for removal of finished compost will occur on average twice per week.
Comment 4: Clarification is needed as to what the health impacts will be to the environment and surrounding area for the 11 toxic air pollutants (TAPs) that exceed the
de minimis thresholds and Renton’s air quality.
King County response: The Puget Sound Clean Air Agency (PSCAA) is currently reviewing the proposed facility’s Notice of Construction application under the New Source Review process. One element of this process is a review of the air quality impacts of Toxic Air pollutants (TAPs)
to demonstrate that the proposed project does not have the potential to adversely affect the health
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of people in the surrounding community. All of the 11 TAPs that exceed the de minimis thresholds had emission rates below their Small Quantity Emission Rates (SQERs). Therefore,
according to PSCAA Regulation III Section 2.07 (c) (1) (A), the facility has demonstrated
compliance with the Acceptable Source Impact Levels (ASILs) for the TAPs. Ambient impacts below ASILs do not have the potential to adversely affect the health of people in the surrounding community.
Under WAC 173-460 (as in PSCAA Regulation I, Section 6.01), facilities submitting a NOC application are required to complete a first-, second-, or third-tier review of the air quality impacts of TAPs to demonstrate that the proposed project does not have the potential to adversely affect the health of people in the surrounding community. TAPs include both carcinogens and non-carcinogens. WAC 173-460-150 lists the regulated TAPs along with their
respective averaging period, Acceptable Source Impact Levels, Small Quantity Emission Rates, and de minimis emission values. Demonstrating compliance with the relevant standards by comparing project emissions to the TAP values listed in WAC 173-460-150 is considered to be a first-tier review.
The de minimis values are defined as the maximum level of emissions that do not pose a threat to human health or the environment. If emissions of a given TAP from a source do not exceed the associated de minimis emission values, then that TAP is exempt from further New Source Review evaluation. However, if emissions of a given TAP do exceed the associated de minimis
emission values, then further NSR evaluation is required and Best Available Control Technology
for Toxics (tBACT) must be demonstrated. In addition to tBACT, each TAP must demonstrate compliance with its respective Acceptable Source Impact Levels by either having an emission rate below the Small Quantity Emission
Rates or conducting air dispersion modeling. The Small Quantity Emission Rate is defined as a level of emissions below which dispersion modeling is not required to demonstrate compliance with Acceptable Source Impact Levels values. The Small Quantity Emission Rates value for each TAP uses a very conservative, assumed dispersion rate to predict whether the emissions
will have an ambient impact below the Acceptable Source Impact Levels. Ambient impacts
below the Acceptable Source Impact Levels do not have the potential to adversely affect the health of people in the surrounding community. Of the 33 TAPs identified as having potential emissions from the Facility, 11 exceeded their de
minimis thresholds. These 11 TAPs, their estimated potential to emit, and their Small Quantity Emission Rates are listed in Table 1. None of the 11 TAPs exceed the Small Quantity Emission Rates; therefore, according to PSCAA Regulation III Section 2.07 (c) (1) (A), the Facility has demonstrated compliance with Acceptable Source Impact Levels for TAPs. The first-tier analysis may be considered complete without requiring dispersion modeling.
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Table 1. TAPs with emission rates exceeding de minimis levels, compared to SQER
TAP CAS Number Emission Rate (lb/averaging period)
Averaging Period SQER (lb/averaging period)
Exceeds SQER?
1,1,2-Trichloroethane 79-00-5 0.85 lb/year 10 No
Allyl chloride 107-05-1 2.1 lb/year 27 No Ammonia 7664-41-7 2.9 lb/24-hr 37 No Benzene 71-43-2 3.4 lb/year 21 No Carbon tetrachloride 56-23-5 9.2 lb/year 27 No
Chloroform 67-66-3 1.7 lb/year 7.1 No
Ethylbenzene 100-41-4 5.4 lb/year 65 No
Hydrogen sulfide 7783-06-4 0.10 lb/24-hr 0.15 No
Napthalene 91-20-3 1.4 lb/year 4.8 No
Triethylamine 121-44-8 0.78 lb/24-hr 15 No
Diesel PM — 0.51 lb/year 0.54 No
CAS = Chemical Abstracts System
Comment 5: Clarification is also needed as to whether the 11 TAPs that exceed de
minimis thresholds are not required to demonstrate compliance because they do not exceed their Small Quantity Emission Rate (SQER) – even though they exceed the de minimis threshold for health impacts.
King County response: Please see the response to Comment 4 above.
Comment 6: Table 1, Page 9 of the SEPA Checklist, identifies odor units per minute
(OU/min). Can King County please compare the OU/min expected to be produced from
this site to the Cedar Grove Composting site in King County? King County response: In 2019, Cedar Grove’s facility in Maple Valley processed 239,523 tons
of green waste and food waste. The County’s Loop compost pilot facility will process
approximately 2,000 tons of material (780 wet tons of biosolids and 600-1300 tons of bulking material/woody material). Therefore, the Loop compost pilot facility will process less than 1 percent of the material processed by the Cedar Grove’s Maple Valley facility. King County’s compost pilot facility will be more similar in size and technology to the Woodland Park Zoo’s
compost facility, which processes about 500 tons per year on 0.23 acres and produces the
popular ZooDoo compost product. The Woodland Park Zoo’s compost facility is located near publicly accessible areas of the zoo, yet receives no odor complaints due to its well-managed operations.
It is generally believed that the aerobic composting of biosolids produces less odor than aerobic
composting of green waste and food waste. However, odor emissions from the Cedar Grove Facility are not available for comparison. Common odorous compounds include VOCs, ammonia, and reduced sulfur compounds. Emissions of reduced sulfur compounds are typically low for properly managed composting processes and a minor contributor to odors. Composting
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using aeration like the County proposes for this facility has a control efficiency of 75 percent or greater.
Odor emissions are regulated through PSCAA Regulation I, Section 9.11, which states: “It shall be unlawful to cause or permit the emission of an air contaminant in sufficient quantities and of such characteristics and duration as is, or is likely to be, injurious to human health, plant or animal life, or property, or which unreasonably interferes with enjoyment of life and property.”
In the PSCAA NOC permit application, the County demonstrates that odor emissions from the facility are unlikely to contribute significantly to ambient odors or to cause a violation of PSCAA Regulation I, Section 9.11 through dispersion modeling of worst-case odor emissions.
Comment 7: Please confirm that you evaluated impacts on the great blue heron which are known to nest at the Black River Riparian Forest, just north of the project site.
King County response: The SEPA checklist identifies the presence of the great blue heron
rookery in the Black River Riparian Forest in Section B.5.a. Chronic human disturbances in the vicinity of a heron rookery can cause nesting failure. The proposed project is unlikely to generate noises or other disturbances that would be discernably different from the existing industrial activities in the area.
Comment 8: Please confirm that that proposed project is not exacerbating the five (5) existing leaking underground tanks (LUSTs) located within the vicinity of the project site, as identified in Section B-7, Environmental Health.
King County response: The project will not affect any known LUSTs. Of the five LUSTs cited in the SEPA checklist, only one was located on the STP campus, but not in the immediate vicinity of the proposed project site. This LUST was reported to Ecology in the 1990s and voluntarily
cleaned up.
Comment 9: In Background Section A-11, you’ve indicated that three (3) blowers would be in nearly constant operation to active composting and curing areas. Please clarify the
direction of the blowers and if these are the same system described in the aeration
process. King County response: The three blowers are the primary components of the forced aeration system described in Section A.11 of the SEPA checklist, the blowers provide reversing aeration
(positive and negative). The aeration system will run according to a system of temperature
sensors and programmable controls for optimal process conditions and odor control, according to desired testing parameters, industry standards and best management practices. The aeration system is automatically reversing, drawing cool air into the compost piles either from the top or bottom. The negative aeration process will draw air from beneath the pile, into air ducts placed
on-grade beneath the pile, and out to a manifold directing the collected air to an odor-scrubbing
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biofilter. The positive aeration process will draw cool air into the fan and push it into the plenum on the floor and up through the pile, which is covered by a biolayer of finished compost or wood
chips for odor and temperature control.
Thank you again for your comments. If you have additional questions or concerns, you may contact me at (206) 477-5395 or jacob.sheppard@kingcounty.gov.
Respectfully,
Jacob Sheppard, Environmental Planner King County Department of Natural Resources and Parks – Wastewater Treatment Division
cc (via email): Katherine Fischer, Environmental Programs Managing Supervisor Ashley Mihle, Project Manager Clark Close, Senior Planner, City of Renton
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Tree Report Page 1 of 6 King County South Treatment Plant
Tree Report
King County South Treatment Plant Biogas and Heat Systems Improvements
February 15, 2018
Prepared by: Mary Ellen Russell
Landscape Architect, Washington no. 1149, 2009
Tree Risk Assessment Qualification, International Society of Arboriculture, 2015
On November 15, 2017, I completed a level 1 (planning level) tree risk assessment for 180 existing trees
at the King County South Treatment Plant near impacts associated with proposed Biogas and Heat
System Improvements. This report details the results of those tree assessments. This report is written in
accordance with the requirements of Renton Municipal Code section 4‐4‐130, Tree Retention and Land
Clearing Regulations. Locations of assessed trees are shown on the Landscape and Tree Retention Plan.
A summary and details of the assessment are shown in the table below.
Of the 180 assessed trees, 42 trees with a Diameter at Breast Height (DBH) greater than 6” are proposed
for removal. 39 trees will be removed due to impacts of construction, 3 trees will be removed due to the
poor condition of the trees which makes their location near construction and proposed facilities high
risk.
All trees proposed to be retained will be protected with high visibility Tree Protection Fencing as shown
on the Landscape and Tree Retention Plans. Wherever possible, tree protection fencing shall be located
10’ from the base of the trunk or at the dripline, whichever is greater, to protect the critical root zone.
For trees to remain, no impacts shall be located closer than 5’ to be base of the trunk or in more than
25% of the critical root zone.
This project proposes to retain all trees for which the impacts of development will be minimal or none.
The tree retention priorities specified in RMC 4‐4‐130H.1.b have been considered as part of this report.
The assessed trees in this report do not include any Landmark (priority one) trees. The trees to be
retained consist of 138 priority two trees.
The existing assessed trees were planted as part of previous development projects with sufficient space
between them to allow development of even canopies. The proposed tree removals will likely not
impact the health or durability of existing trees to remain. The project proposes to retain 76% of the
existing significant trees on site. This is well above the minimum required threshold of 10% per RMC 4‐4‐
130H. No replacement trees are required.
7901 Woodlawn Ave NE, Ste 202
Seattle, WA 98115
206.898.6312
maryellen@russell‐lambert.com
FOR REFERENCE ONLY: While this report
was prepared for another project proposed
at the South Treatment Plant site, it was
used in completing the Tree Retention
Worksheet to show the context and
number of trees on the treatment plant
campus.
EXHIBIT 7
RECEIVED
Clark Close 04/19/2021
PLANNING DIVISION
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Tree Report Page 2 of 6 King County South Treatment Plant
Tree Assessment Summary Table
Tree No. Scientific Name Common Name Size Condition Condition Notes
Significant/ Landmark/
Dangerous
Remove/ Retain
Reason
for Removal:
145 Fraxinus sp. Ash 12" 1 S Retain
146 Fraxinus sp. Ash 6" 1 S Retain
147 Pyrus calleryana Callery Pear 8" 3 Dead branches, lean D* Retain
150 Pinus nigra Black Pine 8" 1 S Retain
152 Fraxinus sp. Ash 8" 2 Broken limb S Retain
153 Pyrus calleryana Callery Pear 13" 2 Stunted S Retain
154 Pyrus calleryana Callery Pear 8" 1 S Retain
156 Pyrus calleryana Callery Pear 10" 1 S Retain
157 Calocedrus decurrens Incense Cedar 12' 1 S Retain
158 Calocedrus decurrens Incense Cedar 12" 1 S Retain
159 Calocedrus decurrens Incense Cedar 12" 1 S Retain
160 Calocedrus decurrens Incense Cedar 14" 1 S Retain
163 Pinus nigra Black Pine 8" 1 S Retain
164 Pinus nigra Black Pine 8" 1 S Retain
167 Pinus nigra Black Pine 8" 1 S Retain
168 Pinus nigra Black Pine 10" 1 S Retain
171 Pinus nigra Black Pine 6" 1 S Retain
173 Pinus nigra Black Pine 9" 2 Lean, corrected S Retain
174 Pinus nigra Black Pine 9" 1 S Retain
177 Fraxinus sp. Ash 7" 1 S Retain
179 Pinus nigra Black Pine 8" 1 S Retain
180 Pinus nigra Black Pine 9" 2 Thin canopy S Retain
181 Pinus nigra Black Pine 8" 2 Thin canopy S Retain
182 Pinus nigra Black Pine 10" 2 Thin canopy S Retain
183 Pinus nigra Black Pine 13" 2 Thin canopy S Retain
184 Pinus nigra Black Pine 8" 2 Thin canopy S Retain
185 Pyrus calleryana Callery Pear 6" 1 S Retain
187 Pinus nigra Black Pine 8" 1 S Retain
188 Liquidambar styraciflua Sweet Gum 6" 2 Dead branches S Retain
189 Pinus nigra Black Pine 12" 1 S Retain
190 Liquidambar styraciflua Sweet Gum 6" 1 S Retain
192 Pinus nigra Black Pine 7" 1 S Retain
194 Pinus nigra Black Pine 10" 1 S Retain
195 Pinus nigra Black Pine 7" 1 S Retain
196 Fraxinus sp. Ash 6" 1 S Retain
346 Malus sp. Crabapple 7" 3 Lean, stunted growth D Retain
349 Malus sp. Crabapple 8" 3 Severely stunted D Remove Condition
366 Calocedrus decurrens Incense Cedar 13" 1 S Retain
393 Pinus nigra Black Pine 12" 1 S Retain
406 Malus sp. Crabapple 8" 2 Response growth S Retain
408 Malus sp. Crabapple 6" 2 Response growth S Retain
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Tree Report Page 3 of 6 King County South Treatment Plant
Tree
No. Scientific Name
Common
Name Size Condition Condition Notes
Significant/
Landmark/
Dangerous
Remove/
Retain
Reason
for
Removal:
412 Fraxinus sp. Ash 6" 1 S Retain
413 Fraxinus sp. Ash 6" 1 S Retain
415 Liquidambar styraciflua Sweet Gum 8" 1 S Remove Impacts
416 Fraxinus sp. Ash 13" 1 S Remove Impacts
419 Fraxinus sp. Ash 9" 1 S Retain
500 Populus nigra Cottonwood 10" 1 S Remove Impacts
501 Populus nigra Cottonwood 8" 1 S Remove Impacts
503 Pseudotsuga menziesii Douglas Fir 9" 1 S Remove Impacts
504 Fraxinus sp. Ash 7" 2 Broken branches S Retain
505 Pseudotsuga menziesii Douglas Fir 6" 1 S Retain
506 Pseudotsuga menziesii Douglas Fir 9" 1 S Retain
507 Pseudotsuga menziesii Douglas Fir 9" 1 S Retain
508 Pseudotsuga menziesii Douglas Fir 9" 1 S Remove Impacts
509 Pseudotsuga menziesii Douglas Fir 9" 1 S Remove Impacts
510 Pseudotsuga menziesii Douglas Fir 9" 1 S Remove Impacts
524 Pinus nigra Black Pine 8" 1 S Retain
525 Pinus nigra Black Pine 9" 2 Stunted S Retain
1405 Pseudotsuga menziesii Douglas Fir 7" 1 S Retain
1443 Picea abies Norway Spruce 16" 1 S Remove Impacts
1444 Picea abies Norway Spruce 11" 1 S Remove Impacts
1445 Picea abies Norway Spruce 16" 1 S Remove Impacts
1446 Picea abies Norway Spruce 14" 1 S Remove Impacts
1450 Picea abies Norway Spruce 10" 1 S Remove Impacts
1451 Picea abies Norway Spruce 8" 1 S Remove Impacts
1452 Picea abies Norway Spruce 17" 1 S Remove Impacts
1453 Pseudotsuga menziesii Douglas Fir 6" 1 S Remove Impacts
1455 Pseudotsuga menziesii Douglas Fir 7" 1 S Remove Impacts
1456 Picea abies Norway Spruce 8" 1 S Remove Impacts
1636 Malus sp. Crabapple 11" 2
Pruned limbs, response
growth S Remove Impacts
1637 Malus sp. Crabapple 10" 2
Pruned limbs, response
growth S Remove Impacts
1638 Malus sp. Crabapple 10" 2 Pruned limbs, response growth S Remove Impacts
1639 Malus sp. Crabapple 8" 2
Pruned limbs, response
growth S Remove Impacts
1640 Malus sp. Crabapple 7" 2
Pruned limbs, response
growth S Remove Impacts
1641 Malus sp. Crabapple 7" 2
Pruned limbs, response
growth S Remove Impacts
1830 Prunus laurocerasus Laurel 13" 2 Pruned to shrub form S Retain
1831 Pinus nigra Pinus nigra 12" 1 S Retain
1832 Pinus nigra Pinus nigra 13" 1 S Retain
1862 Prunus laurocerasus Laurel 13" 2 Pruned to shrub form S Remove Impacts
1863 Prunus laurocerasus Laurel 14" 2 Pruned to shrub form S Retain
2038 Pinus nigra Pinus nigra 14" 1 S Retain
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Tree Report Page 4 of 6 King County South Treatment Plant
Tree
No. Scientific Name
Common
Name Size Condition Condition Notes
Significant/
Landmark/
Dangerous
Remove/
Retain
Reason
for
Removal:
2039 Mystery Mystery 12" 1 S Retain
4230 Calocedrus decurrens Incense Cedar 7" 1 S Retain
4231 Fraxinus sp. Ash 6" 1 S Retain
4242 Fraxinus sp. Ash 7" 2 Response growth at base S Retain
4282 Fraxinus sp. Ash 7" 1 S Retain
4288 Pseudotsuga menziesii Douglas Fir 12" 1 S Retain
4295 Fraxinus sp. Ash 6" 1 S Retain
4296 Fraxinus sp. Ash 7" 1 S Retain
4297 Pseudotsuga menziesii Douglas Fir 12" 1 S Retain
4298 Pseudotsuga menziesii Douglas Fir 12" 1 S Remove
4388 Fraxinus sp. Ash 6" 1 S Retain
4389 Larix sp. Larch 6" 4 dead limbs, large cracks D Remove
4399 Larix sp. Larch 6" 4 dead limbs, large cracks D* Retain
4400 Pseudotsuga menziesii Douglas Fir 12" 1 S Remove
4401 Larix sp. Larch 6" 4 Mostly dead D* Retain
4409 Cretaegus x lavalleei Hawthorn 6" 2 Shrubby w/ root sprouts S Retain
4410 Cretaegus x lavalleei Hawthorn 6" 2 Shrubby w/ root sprouts S Retain
4411 Pseudotsuga menziesii Douglas Fir 11" 1 S Retain
4412 Pseudotsuga menziesii Douglas Fir 11" 1 S Retain
4413 Pseudotsuga menziesii Douglas Fir 12" 1 S Retain
4414 Pseudotsuga menziesii Douglas Fir 12" 1 S Retain
4415 Pseudotsuga menziesii Douglas Fir 12" 1 S Retain
4416 Pseudotsuga menziesii Douglas Fir 13" 1 S Retain
4417 Pseudotsuga menziesii Douglas Fir 13" 1 S Retain
4418 Pseudotsuga menziesii Douglas Fir 14" 1 S Retain
4419 Fraxinus sp. Ash 6" 2 Response growth at base S Retain
4420 Fraxinus sp. Ash 6" 1 S Retain
4632 Fraxinus sp. Ash 8" 1 S Retain
4633 Fraxinus sp. Ash 7" 1 S Retain
4635 Calocedrus decurrens Incense Cedar 8" 1 S Retain
4636 Calocedrus decurrens Incense Cedar 6" 1 S Retain
4637 Calocedrus decurrens Incense Cedar 10" 1 S Retain
4638 Fraxinus sp. Ash 11" 1 S Retain
4639 Pseudotsuga menziesii Douglas Fir 10" 1 S Retain
4857 Fraxinus sp. Ash 6" 2 Damage at base of trunk S Retain
4858 Fraxinus sp. Ash 7" 1 S Retain
4859 Fraxinus sp. Ash 6" 2 Damage at base of trunk S Retain
4860 Pseudotsuga menziesii Douglas Fir 7" 1 S Retain
4861 Pseudotsuga menziesii Douglas Fir 10" 1 S Retain
4862 Pseudotsuga menziesii Douglas Fir 10" 2 Missing leader S Remove
4863 Pseudotsuga menziesii Douglas Fir 11" 1 S Remove
4864 Pseudotsuga menziesii Douglas Fir 11" 1 S Remove
4893 Fraxinus sp. Ash 6" 1 S Retain
4894 Fraxinus sp. Ash 7" 1 S Remove
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Tree Report Page 5 of 6 King County South Treatment Plant
Tree
No. Scientific Name
Common
Name Size Condition Condition Notes
Significant/
Landmark/
Dangerous
Remove/
Retain
Reason
for
Removal:
4897 Pseudotsuga menziesii Douglas Fir 11" 1 S Remove
4899 Pseudotsuga menziesii Douglas Fir 10" 1 S Remove
4900 Pseudotsuga menziesii Douglas Fir 10" 1 S Remove
4901 Pseudotsuga menziesii Douglas Fir 8" 1 S Remove
4947 Pyrus calleryana Callery Pear 6" 1 S Retain
5010 Calocedrus decurrens Incense Cedar 9" 1 S Remove
5011 Calocedrus decurrens Incense Cedar 11" 1 S Remove Impacts
5015 Pseudotsuga menziesii Douglas Fir 11" 1 S Remove
5016 Pseudotsuga menziesii Douglas Fir 9" 2 Topped S Remove Impacts
5059 Pseudotsuga menziesii Douglas Fir 14" 1 S Retain
5066 Pseudotsuga menziesii Douglas Fir 11" 1 S Retain
5067 Pseudotsuga menziesii Douglas Fir 12" 1 S Retain
5138 Calocedrus decurrens Incense Cedar 7" 1 S Retain
5140 Populus nigra Black Poplar 8" 1 S Retain
5161 Pseudotsuga menziesii Douglas Fir 7" 3 Severely broken leader D* Retain
5173 Calocedrus decurrens Incense Cedar 6" 1 S Remove
5232 Calocedrus decurrens Incense Cedar 11" 1 S Retain
5233 Calocedrus decurrens Incense Cedar 12" 1 S Retain
5234 Calocedrus decurrens Incense Cedar 12" 1 S Retain
*This tree is in decline. However, its location makes it unlikely to impact any target in the event of failure.
Therefore, despite its poor health, this tree may be retained with low risk. Trees in decline provide beneficial
habitat. If this area is impacted or improved, this tree should be removed.
Condition Key:
1) Excellent condition and vigor, no defects noted
2) Good condition and vigor, minor defects or signs of decay, but no significant risk
3) Fair condition and vigor, defects or signs of decay are present but do not pose significant risk
4) Poor condition and vigor, significant defects, significantly declining, dying, or dead tree
Limit of Liability
The terms and evaluation forms used in this report are as laid out in the International Society of
Arboriculture Tree Risk Assessment Manual, 2013.
There are many conditions affecting a tree’s health and stability which may be present and cannot
be ascertained, such as root rot, previous or unexposed construction damage, internal cracks, stem
rot and more. Changes in circumstances and conditions can also cause a rapid deterioration of a
tree’s health and stability. Adverse weather conditions can dramatically affect the health and safety
of a tree in a very short amount of time. While I have used every reasonable means to examine
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Tree Report Page 6 of 6 King County South Treatment Plant
these trees, this evaluation represents my opinion of the tree health at the time of the evaluation
only. These findings do not guarantee future safety nor are they predictions of future events.
The tree evaluation is a Level 1 Assessment as defined by the International Society of Arboriculture.
It consists of a brief external visual inspection of an individual tree’s root flare, trunk, and canopy
from the ground only unless otherwise specified. As conditions change, it is the responsibility of the
property owners to schedule additional site visits by the necessary professionals to monitor the
long‐term health and risk of the tree.
This tree evaluation is to be used to inform and guide the property owner in the management of
their trees. This in no way implies that the evaluator is responsible for performing recommended
actions or using other methods or tools to further determine the extent of internal tree problems
without written authorization from the property owner. Furthermore, the evaluator in no way holds
that the recommendations are the only actions required to insure that the tree will not fail. Extreme
weather conditions can cause even low risk trees to fail.
A second opinion maybe sought if the client so desires. The client shall hold the evaluator harmless
for any and all injuries or damages incurred if the tree examined fails for any reason or if the
evaluator’s recommendations are not followed or for acts of nature beyond the evaluator’s
reasonable expectations, such as severe winds, excessive rains, heavy snow loads, etc.
If you have any further questions, please do not hesitate to call.
Sincerely,
Mary Ellen Russell, PLA
Principal, Russell + Lambert Landscape Architects
ISA Qualified Tree Risk Assessor
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
LIMIT OF DISTURBANCE, TYPICAL
EXISTING
MEADOW AREA
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PLANTING LEGEND
LIQUIDAMBAR STYRACIFLUA - SEE PLANT SCHEDULE
PSEUDOTSUGA MENZIESII - SEE PLANT SCHEDULE
MEADOW SEED MIX
TREE RETENTION LEGEND
TREE RETENTION NOTES:
1.WHEREVER FEASIBLE, TREE PROTECTION FENCING SHALL BE LOCATED A
MINIMUM OF 10' FROM THE TRUNK OR AT THE DRIP LINE, WHICHEVER IS
GREATER. WHERE SITE IMPACTS OCCUR LESS THAN 10' FROM THE TREE
TRUNK, TREE PROTECTION FENCING SHALL BE LOCATED A MINIMUM OF 5'
FROM THE TRUNK. TREES THAT WILL BE IMPACTED CLOSER THAN 5' FROM
THE TRUNK, OR TREES WHO WILL BE IMPACTED IN MORE THAN 25% OF THE
CRITICAL ROOT ZONE SHALL BE REMOVED.
EXISTING DECIDUOUS TREE TO REMAIN
EXISTING EVERGREEN TREE TO REMAIN
EXISTING DECIDUOUS TREE TO BE REMOVED
EXISTING EVERGREEN TREE TO BE REMOVED
EXISTING DECIDUOUS TREE LESS THAN 6" DBH TO REMAIN
EXISTING EVERGREEN TREE LESS THAN 6" DBH TO REMAIN
EXISTING DECIDUOUS TREE LESS THAN 6" DBH TO BE REMOVED
EXISTING EVERGREEN TREE LESS THAN 6" DBH TO BE REMOVED
TREE PROTECTION FENCING
AREA SHOWN ON THIS PLAN
WWTP KEY PLAN
NO SCALE
1
2
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DESIGNED/DRAWN:
PROJECT ENGINEER:
PROJECT ACCEPTANCE:
DESIGN APPROVAL:
CONTRACT NO:
DRAWING NO:
PROJECT FILE NO:SCALE:
FACILITY NUMBER:
DEPARTMENT OF NATURAL RESOURCES & PARKSWASTEWATER TREATMENT DIVISION
DATE:
SHT NO / TOTAL REVNO:
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SOUTH TREATMENT PLANT
BIOGAS AND HEAT SYSTEMS IMPROVEMENTS
FEB 2018
15-xxxxxxx
NO REVISION DESCRIPTION BY APVD DATE
EFGHBCDA
S. Hildreth
PRELIMINARY ISSUE DRAWING
90% REVIEW
FEBRUARY 2018
I. McKelvey
C01248C18
LANDSCAPE AND TREE RETENTION PLAN
AREA 21 L2240105
R. Lambert
R. Lambert 1" = 20'
0
R. Bard
MATCH LINE - SEE DWG L2240106
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STATE OFWASHINGTONREGISTEREDLANDSCAPE ARCHITECT
RYAN D. LAMBERT
CERTIFICATE NO. 1190
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EXHIBIT 8
RECEIVED
Clark Close 04/19/2021
PLANNING DIVISION
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
DEPARTMENT OF COMMUNITY
AND ECONOMIC DEVELOPMENT
TREE RETENTION WORKSHEET
Planning Division
1055 South Grady Way-Renton, WA 98057
Phone: 425-430-7200 | www.rentonwa.gov
1.Total number of trees over 6” diameter1, or alder or cottonwood
trees at least 8” in diameter on project site trees
2.Deductions: Certain trees are excluded from the retention calculation:
Trees that are dangerous2 trees
Trees in proposed public streets trees
Trees in proposed private access easements/tracts trees
Trees in critical areas3 and buffers trees
Total number of excluded trees: trees
3.Subtract line 2 from line 1:trees
4.Next, to determine the number of trees that must be retained4, multiply line 3 by:
0.3 in zones RC, R-1, R-4, R-6 or R-8
0.2 in all other residential zones
0.1 in all commercial and industrial zones trees
5.List the number of 6” in diameter, or alder or cottonwood trees
over 8” in diameter that you are proposing5 to retain4:trees
6.Subtract line 5 from line 4 for trees to be replaced:
(if line 6 is zero or less, stop here. No replacement trees are required) trees
7.Multiply line 6 by 12” for number of required replacement inches:inches
8.Proposed size of trees to meet additional planting requirement:
(Minimum 2” caliper trees required for replacement, otherwise enter 0)inches per tree
9.Divide line 7 by line 8 for number of replacement trees6: (If remainder is .5 or greater, round up to the next whole number) trees
1 Measured at 4.5’ above grade. 2 A tree certified, in a written report, as dead, terminally diseased, damaged, or otherwise dangerous to persons or property by a licensed
landscape architect, or certified arborist, and approved by the City. 3 Critical areas, such as wetlands, streams, floodplains and protected slopes, are defined in RMC 4-3-050. 4 Count only those trees to be retained outside of critical areas and buffers. 5 The City may require modification of the tree retention plan to ensure retention of the maximum number of trees per RMC 4-4-130H7a. 6 When the required number of protected trees cannot be retained, replacement trees, with at least a two-inch (2") caliper or an evergreen at least
six feet (6') tall, shall be planted. See RMC 4-4-130.H.1.e.(ii) for prohibited types of replacement trees.
1
H:\CED\Data\Forms-Templates\Self-Help Handouts\Planning\Tree Retention Worksheet.docx 08/2015
EXHIBIT 9
RECEIVED
Clark Close 04/19/2021
PLANNING DIVISION
180
3
0
0
0
3
177
18
164
(146)
(1,756)
0
0
Print Form Reset Form Save FormDocusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
1,128 94
Compost Pilot Project - Tree Removal
This map is a user generated static output from an Internet mapping site and
is for reference only. Data layers that appear on this map may or may not be
accurate, current, or otherwise reliable.
None
3/16/2021
Legend
640 32
THIS MAP IS NOT TO BE USED FOR NAVIGATION
Feet
Notes
64
WGS_1984_Web_Mercator_Auxiliary_Sphere
Information Technology - GIS
RentonMapSupport@Rentonwa.gov
City and County Labels
Addresses
Parcels
City and County Boundary
<all other values>
Renton
Streets
Points of Interest
Parks
Waterbodies
2019.sid
Red: Band_1
Green: Band_2
Blue: Band_3
RECEIVED
Clark Close 04/19/2021
PLANNING DIVISION
13 Cedar Trees
Proposed for Removal
Work Limits (approx)
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information
Report (TIR) – 60%
Design
King County South Wastewater Treatment Plant
Loop Pilot Compost Facility
DRAFT
Renton, Washington March 10, 2021
EXHIBIT 10
RECEIVED
Clark Close 04/19/2021
PLANNING DIVISION
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
This page is intentionally left blank.
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design
King County South Wastewater Treatment Plant Loop Pilot Compost Facility
March 10, 2021 | i
Contents
1 Project Overview ................................................................................................................................. 1
2 Conditions and Requirements Summary ............................................................................................ 9
2.1 Core Requirements ................................................................................................................... 9
2.1.1 Core Requirement #1: Discharge at the Natural Location ........................................... 9 2.1.2 Core Requirement #2: Offsite Analysis ...................................................................... 10 2.1.3 Core Requirement #3: Flow Control Facilities ........................................................... 10 2.1.4 Core Requirement #4: Conveyance Systems ............................................................ 10 2.1.5 Core Requirement #5: Construction Stormwater Pollution Prevention ...................... 11
2.1.6 Core Requirement #6: Maintenance and Operations ................................................ 11 2.1.7 Core Requirement #7: Financial Guarantees and Liabilities...................................... 11 2.1.8 Core Requirement # 8: Water Quality Facilities ......................................................... 11 2.1.9 Core Requirement #9: On-site BMPs ......................................................................... 11
2.2 Special Requirements ............................................................................................................. 11
2.2.1 Special Requirement #1: Other Adopted Area-Specific Requirements ..................... 11
2.2.2 Special Requirement #2: Flood Hazard Area Delineation ......................................... 11 2.2.3 Special Requirement #3: Flood Protection Facilities ................................................. 12 2.2.4 Special Requirement #4: Source Controls ................................................................. 12 2.2.5 Special Requirement #5: Oil Control .......................................................................... 12
3 Offsite Analysis .................................................................................................................................. 12
3.1 Task 1: Study Area Definition and Maps ................................................................................. 12
3.2 Task 2: Resource Review ....................................................................................................... 13
3.3 Task 3: Field Inspection .......................................................................................................... 14
3.4 Task 4: Drainage System Description and Problem Descriptions .......................................... 14
3.5 Task 5: Mitigation of Existing or Potential Problems ............................................................... 16
4 Flow Control, Low Impact Development (LID) and Water Quality Facility Analysis and Design ............................................................................................................................................... 16
4.1 Part A - Existing Site Hydrology .............................................................................................. 16
4.2 Part B - Developed Site Hydrology ......................................................................................... 18
4.3 Part C - Performance Standards ............................................................................................. 20
4.4 Part D - Flow Control System .................................................................................................. 20
4.5 Part E - Water Quality System ................................................................................................ 22
5 Conveyance System Analysis and Design ........................................................................................ 22
6 Special Reports and Studies ............................................................................................................. 23
7 Other Permits .................................................................................................................................... 23
8 CSWPP Analysis and Design............................................................................................................ 23
8.1 Part A – ESC Plan Analysis and Design ................................................................................. 23
8.2 Part B – SWPPS Plan Design ................................................................................................. 25
9 Bond Quantities, Facility Summaries, and Declaration of Covenant ................................................ 25
10 Operations and Maintenance Manual ............................................................................................... 27
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design King County South Wastewater Treatment Plant Loop Pilot Compost Facility
ii | March 10, 2021
Tables
Table 1. Offsite analysis drainage system table ......................................................................................... 16
Table 2. Existing land cover ........................................................................................................................ 17
Table 3. Proposed land cover ..................................................................................................................... 18
Table 4. Conveyance pipe maintenance ..................................................................................................... 27
Table 5. Grounds maintenance ................................................................................................................... 28
Table 6. Catch basin and manhole maintenance ....................................................................................... 29
Figures
Figure 1. TIR worksheet ................................................................................................................................ 2
Figure 2. Site location ................................................................................................................................... 7
Figure 3. Drainage basins, subbasins, and site characteristics .................................................................... 8
Figure 4. Soils ............................................................................................................................................... 9
Figure 5. Offsite study area ......................................................................................................................... 13
Figure 6. Sensitive areas ............................................................................................................................ 14
Figure 7. Downstream conveyance ............................................................................................................ 15
Figure 8. Existing hydrology ........................................................................................................................ 18
Figure 9. Proposed hydrology ..................................................................................................................... 20
Figure 10. WWHM peak flow rate results ................................................................................................... 21
Figure 11. WWHM LID duration results ...................................................................................................... 21
Figure 12. Conveyance calculations ........................................................................................................... 22
Appendices
Appendix A. Erosion Sediment Control Plan .............................................................................................A-1
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design
King County South Wastewater Treatment Plant Loop Pilot Compost Facility
March 10, 2021 | 1
1 Project Overview
An overview of project stormwater elements is given in the Technical Information Report
(TIR) worksheet (Figure 1). The project is located in Renton, Washington at the King
County South Wastewater Treatment Plant (South Plant) (Figure 2).
The purpose of the project is to construct a small-scale, temporary pilot demonstration
(not for a permanent facility) to pilot an alternative process at King County’s South Plant
which will further process Class B Loop® biosolids into a Class A Loop compost. Once
operational, information from the composting pilot will be used to demonstrate proof of
concept and develop a business case for composting, develop reliable sources of
feedstocks and bulking agents, conduct product and process optimization, develop
markets and distribution channels, build community support and collect data to inform the
capital project process for a larger, permanent facility (located off-site).
The site is divided into two basins which are within the same threshold discharge area
(TDA) with a total site area of 0.7376 acres. Both basins currently sheet flow to an
adjacent access road where runoff is collected at catch basins (Figure 3) and conveyed
in the wastewater treatment plant’s stormwater system to an outfall in the Black River. In
Drainage Basin 1, a Finished Product Storage area will be constructed, a non-pollution
generating impervious surface constructed from crushed gravel, and will continue to
sheet flow to the access road with runoff collected by the stormwater system. Drainage
Basin 2 will house the composting facility. As a composting facility, all stormwater that
contacts any active composting areas is considered leachate. Per source control best
management practice (BMP) A-24 from the King County Stormwater Pollution Prevention
Manual, all leachate from composting operations should drain to a sanitary sewer.
Therefore, all runoff from the impervious surfaces in Drainage Basin 2 will have all runoff
collected in new catch basins which will discharge into the sanitary sewer system. The
sanitary sewer system will convey collected runoff to South Plant.
Soils at the project site per the NRCS Websoil Survey consist of sandy loams (Figure 4).
The 2001 report by CivilTech states that existing documents indicate that the site was
covered with fill material as part of the Enlargement II project in the 1980’s. At that time
the elevation of the site was raised from 116 to 126 feet and was relatively flat. A 2019
survey reports a site elevation of 126 feet, so there has not been significant settling.
Previous geotechnical field explorations determined the subsurface condition at the site
by performing four Cone Penetration Tests (CPT). The CPT test results were correlated
with borings previously completed in the vicinity of the site by Shannon & Wilson, Inc.
and referenced in a 1992 report entitled Final Design Geotechnical Report, Metro Renton
Wastewater Treatment Plant Enlargement III, Renton, Washington and a 1993 report
entitled Geotechnical Report, Metro Renton Wastewater Treatment Plant Enlargement II,
Solid Stream Improvements (Contract III C). Based on these reports, the soils at the site
The capturing of Drainage Basin 2 by the sanitary sewer system provides all flow
control and water quality treatment necessary. Stormwater runoff from the project
site will decrease after the completion of the project and therefore meets the flow
control and low impact development standards. No other stormwater related
facilities are construct ed as part of this project.
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design King County South Wastewater Treatment Plant Loop Pilot Compost Facility
2 | March 10, 2021
consist of a layer of fill soils mantling native soils. The fill soils consist of soft to stiff,
sandy, clayey silt and extend to a depth of approximately 17 feet. The groundwater table
is expected to be on the order of 22 to 23 feet below the ground surface. The risk of
liquefaction is minimal.
Figure 1. TIR worksheet
King County (Ashley Mihle, PM)
1200 Monster Rd SW
Renton, WA
Jeff Hansen
HDR
360.570.4410
SWWTP Loop Pilot Compost Facility
1200 Monster Rd SW
Renton, WA
T23N
R04E
24
X
X
X
Jan 12, 2020
Feb 2020
206.477.2743
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design
King County South Wastewater Treatment Plant Loop Pilot Compost Facility
March 10, 2021 | 3
Duwamish – Green River: Black River
X
X
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design King County South Wastewater Treatment Plant Loop Pilot Compost Facility
4 | March 10, 2021
Sandy loam 1% to 9% Low
None known
None known
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design
King County South Wastewater Treatment Plant Loop Pilot Compost Facility
March 10, 2021 | 5
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design King County South Wastewater Treatment Plant Loop Pilot Compost Facility
6 | March 10, 2021
X
X
X
X
X
X
X
X
X
X
X
X Discharge to sanitary system leading to WWTP. Discharge to sanitary system leading to WWTP.
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design
King County South Wastewater Treatment Plant Loop Pilot Compost Facility
March 10, 2021 | 7
Figure 2. Site location
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design King County South Wastewater Treatment Plant Loop Pilot Compost Facility
8 | March 10, 2021
Figure 3. Drainage basins, subbasins, and site characteristics
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design
King County South Wastewater Treatment Plant Loop Pilot Compost Facility
March 10, 2021 | 9
Figure 4. Soils
2 Conditions and Requirements Summary
This section contains a summary of the applicability of the core and special requirements
as outlined in the City of Renton 2017 Surface Water Design Manual (SWDM).
2.1 Core Requirements
2.1.1 Core Requirement #1: Discharge at the Natural Location
Currently, runoff from the site sheet flows to an adjacent access road where runoff is
collected in catch basins and conveyed in the stormwater system through the treatment
plant site, where stormwater then is discharged to an outfall to the Black River (on the
east side of the South Plant site) which ultimately flows to the Puget Sound. After
construction, runoff from all areas of the site except for the Finished Product Storage
area will enter catch basins (that are separate from the stormwater system) and enter the
sanitary sewer system which is conveyed to the South Plant’s treatment system which
discharges to Puget Sound through a 12-mile long, 8-foot diameter transfer line. The
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design King County South Wastewater Treatment Plant Loop Pilot Compost Facility
10 | March 10, 2021
Finished Product Storage area will continue to sheet flow to the access road with runoff
collected by the existing stormwater catch basins.
As discussed in Section 3.2, there are steep slopes in the vicinity of the project site.
However, in all cases, stormwater will be collected into tightline systems at or
immediately adjacent to the project site and will not discharge to any steep slopes.
2.1.2 Core Requirement #2: Offsite Analysis
Per the SWDM all projects must submit an offsite analysis report that assesses potential
offsite drainage and water quality impacts associated with development of the project
site, and that proposes appropriate mitigation of those impacts. All runoff from the project
area, except for the Finished Product Storage area, will be collected via catch basins and
enter the sanitary sewer system for treatment at the wastewater treatment plant while the
Finished Product Storage area will continue to discharge to existing stormwater catch
basins. This causes a net decrease in the flows entering the stormwater system. A Level
1 Offsite Analysis was completed for the project and discussed in Section 3.
2.1.3 Core Requirement #3: Flow Control Facilities
Per the SWDM, all proposed projects, including redevelopment projects, must provide
onsite flow control facilities to mitigate the impacts of storm and surface water runoff
generated by new impervious surface, new pervious surface, and replaced impervious
surface targeted for flow mitigation.
Per the City’s flow control application map, the project site is within an area where a peak
rate flow control standard is used against existing site conditions.
With all runoff from the project area, except for the Finished Product Storage area, being
collected via catch basins and entering the sanitary sewer system for treatment at the
wastewater treatment plant while the Finished Product Storage area will continue to
discharge to existing stormwater catch basins, a net decrease in the flows entering the
stormwater system is seen without the use of flow control infrastructure. Therefore, the
project meets the peak flow rate control standard of having the proposed peak discharge
rates for the 2-, 10-, and 100-year return periods staying below the existing peak
discharge rates.
2.1.4 Core Requirement #4: Conveyance Systems
All pipe conveyance systems were designed to convey the 25-year peak flow rate per the
SWDM. Peak flow rates were calculated using the rational method per Section 3.2.1 of
the SWDM. Additional discussion of conveyance systems is provided in Section 5.
Modeling of the runoff from the site tributary to the existing conveyance system (Section
4.4) shows that peak runoff to the existing storm system will decrease because most of
the site will change to being conveyed into the sanitary sewer system. Because of this a
capacity analysis was not completed for the existing storm system. Capacity sizing was
completed for the new piping to connect to the sanitary sewer system and is discussed in
Section 5.
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design
King County South Wastewater Treatment Plant Loop Pilot Compost Facility
March 10, 2021 | 11
2.1.5 Core Requirement #5: Construction Stormwater Pollution Prevention
Construction stormwater pollution is being provided as part of the project which meets
the requirements of the SWDM. Further discussion is provided in Section 8.
2.1.6 Core Requirement #6: Maintenance and Operations
Ongoing maintenance and operation of the facilities after the completion of construction
will be completed by King County. Additional information on O&M is provided in Section
10.
2.1.7 Core Requirement #7: Financial Guarantees and Liabilities
Discussions regarding Core Requirement # 7, including information regarding the Site
Improvement Bond Quantities Worksheet and Flow Control and Water Quality Facility
Summary Sheet and Sketch are found in Section 9.
2.1.8 Core Requirement # 8: Water Quality Facilities
Water quality treatment will be provided for all pollution-generating impervious surfaces
which will drain to the sanitary sewer system and conveyed to South Plant for treatment.
2.1.9 Core Requirement #9: On-site BMPs
The project can be considered a commercial composting facility where any stormwater
contacting any active composting areas is considered leachate. Per BMP A-24
(commercial composting) of the King County Stormwater Pollution Prevention Manual, all
leachate should drain to the sanitary sewer. Because of this all runoff from the project
area, except for the Finished Product Storage area, is being collected via catch basins
and discharged to the sanitary sewer system for treatment at the wastewater treatment
plant while the Finished Product Storage area will continue to discharge to existing
stormwater catch basins. By having most of the area drain to the sanitary sewer, a net
decrease in the flows entering the stormwater system is seen without the use of flow
control infrastructure. The net decrease in discharge to the stormwater system surpasses
the low impact development (LID) performance standard.
2.2 Special Requirements
2.2.1 Special Requirement #1: Other Adopted Area-Specific
Requirements
As the project resides in the City of Renton, the project was designed to conform to the
requirements of the 2017 Renton Surface Water Design Manual.
2.2.2 Special Requirement #2: Flood Hazard Area Delineation
The City of Renton GIS maps show that the project site is outside of the 100-year flood
plain.
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design King County South Wastewater Treatment Plant Loop Pilot Compost Facility
12 | March 10, 2021
2.2.3 Special Requirement #3: Flood Protection Facilities
There are no flood protection facilities located on or directly adjacent to the site.
2.2.4 Special Requirement #4: Source Controls
A commercial building or commercial site development permit are not needed as part of
his project. Therefore this special requirement does not apply for this project.
2.2.5 Special Requirement #5: Oil Control
The project does not develop or redevelop or considered a high-use site based upon the
number of anticipated average daily trips (ADTs). Therefore this special requirement
does not apply for this project.
3 Offsite Analysis
This section summarizes the Level 1 offsite analysis completed for the project.
3.1 Task 1: Study Area Definition and Maps
The offsite study area is shown on Figure 5. The offsite drainage area tributary to the
project site is limited to the area between the site and the access road immediately to the
west of the Finished Product Storage area (approximately 60 feet away). Therefore,
offsite drainage tributary to the site is limited.
The project site currently drains to a stormwater conveyance system which drains to a
stormwater pump station approximately 1,100 feet downstream. The pump station then
pumps through approximately 2,000 feet of force main. After flowing approximately 1,700
feet through a series of wet ponds and wetlands, stormwater is discharged to the Black
River (Springbrook Creek) at an outfall approximately 4,800 feet downstream from the
site. From the outfall, runoff from the site flows approximately 4,100 feet down the Black
River until it reaches the Duwamish River—passing through the Black River Pump
Station in-between.
After the project is completed, the Finished Product Storage area will continue to follow
the above flow path shown on Figure 5; however, the rest of the site will discharge to the
sanitary sewer system and flow into the South Plant treatment system.
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design
King County South Wastewater Treatment Plant Loop Pilot Compost Facility
March 10, 2021 | 13
Figure 5. Offsite study area
3.2 Task 2: Resource Review
Figure 6 provides an overview of sensitive areas near the project site and offsite study
area. Slopes hazard and seismic hazards exist within the immediate project site while
wetlands and flood hazards exists in the offsite study area.
As part of the resource review, the City of Renton Basin Locations map was also
reviewed which shows that the site is within the Black River basin and the Duwamish
watershed.
A review of the Washington State Department of Ecology’s published Clean Water Act
Section 303d list of polluted waters shows that the Black River (which the stormwater
system discharges to) is a 303d listed water body for dissolved oxygen, bioassessment,
and bacteria.
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Technical Information Report (TIR) – 60% Design King County South Wastewater Treatment Plant Loop Pilot Compost Facility
14 | March 10, 2021
Figure 6. Sensitive areas
3.3 Task 3: Field Inspection
Due to the COVID, a field inspection was not completed. However, no drainage issues
were reported by South Plant staff.
3.4 Task 4: Drainage System Description and Problem
Descriptions
The downstream drainage path for stormwater collected by the stormwater conveyance
system within a quarter mile of the site is shown on Figure 7. From the project site,
stormwater is collected by several catch basins and conveyed south through a 12-inch
pipe (Item #1). This is then intercepted by a 30-inch pipe and conveyed to a stormwater
pump station (Item #2). The pump station then discharges to a 12-inch force main (Item
#3) and then discharges to a series of wet ponds and a wetland.
There are no known drain problems, inadequate capacity, or erosion problems within a
quarter mile downstream from the project site. Any unidentified issues will not be made
worse by the project due to the project reducing the stormwater runoff from the project
site.
A summary of the downstream conveyance features and distance from the site discharge
are given in Table 2.
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Figure 7. Downstream conveyance
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Table 1. Offsite analysis drainage system table
Symbol Drainage component
Drainage component description Slope %
Distance from site discharge Existing problems Potential problems Observations
Item #1 Existing 100 ft of 12-inch pipe
Collects runoff from access road CBs and conveys to 30-inch pipe.
Unknown 0 to 100 ft None None None
Item #2 Existing 1,000 ft of 30-inch pipe
Conveys stormwater to Pump Station
Unknown 100 to 1,100 ft None None None
Item #3 Pump station and existing 2,000 ft of 12-inch force main
Conveys stormwater to wet ponds
N/A 1,100 to 3,100 ft None None None
3.5 Task 5: Mitigation of Existing or Potential Problems
No existing problems are known within a quarter mile of the site discharge. Once the
project is completed, due to all areas of the site except for the Finished Product Storage
area draining to the sanitary sewer system, the runoff to the storm system will decrease
which will mitigate any additional runoff generated by the impervious surfaces added by
the project. Therefore, no potential problems are expected by the creation of this project.
4 Flow Control, Low Impact Development
(LID) and Water Quality Facility Analysis
and Design
4.1 Part A - Existing Site Hydrology
The site is divided into two basins which are within the same TDA with a total site area of
0.7376 acres. Both basins currently sheet flow to an adjacent access road where runoff
is collected at catch basins (Figure 3) and conveyed in the wastewater treatment plant’s
stormwater system to an outfall in the Black River (see Figure 5and Figure 7). The
existing hydrology and land cover are shown on Figure 8 with land cover areas
summarized in Table 2.
The soils at the site consist of a layer of fill soils mantling native soils. The fill soils
consist of soft to stiff, sandy, clayey silt and extend to a depth of approximately 17 feet.
Soils were assumed to have characteristics of till for modeling.
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Table 2. Existing land cover
Land cover Area (acres)
Drainage Basin 1
Impervious 0.0334
Pervious 0.0563
Total area 0.0897
Drainage Basin 2
Impervious 0.4727
Pervious 0.1752
Total area 0.6479
Total Project Site
Impervious 0.5061
Pervious 0.2315
Total area 0.7376
Offsite run-on to Drainage Basin 1
Impervious 0.0628
Pervious 0.0677
Total area 0.1305
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Figure 8. Existing hydrology
4.2 Part B - Developed Site Hydrology
In Drainage Basin 1, a Finished Product Storage area will be constructed, a non-pollution
generating impervious surface constructed from crushed gravel, and will continue to
sheet flow to the access road with runoff collected by the stormwater system. Drainage
Basin 2 will house the composting facility and will have all runoff collected in new catch
basins which will discharge into the sanitary sewer system. The sanitary sewer system
will convey collected runoff to South Plant. The capturing of Drainage Basin 2 by the
sanitary sewer system provides any flow control and water quality treatment necessary.
No other stormwater related facilities are constructed as part of this project.
The proposed hydrology and land cover are shown on Figure 8 with land cover areas
summarized in Table 3. No change is soils will occur as part of the project. Soils were
assumed to have characteristics of till for modeling.
Table 3. Proposed land cover
Land cover Area (acres)
Drainage Basin 1
Impervious 0.0897
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Table 3. Proposed land cover
Land cover Area (acres)
Pervious 0.0000
Total area 0.0897
Drainage Basin 2
Impervious 0.5492
Pervious 0..0987
Total area 0.6479
Total Project Site
Impervious 0.6389
Pervious 0.0987
Total area 0.7376
Offsite run-on to Drainage Basin 1
Impervious 0.0628
Pervious 0.0677
Total area 0.1305
The proposed site will create 5,731 square feet of new impervious surface while
converting 390 square feet of impervious surface to pervious surface for a net increase
of 5,341 square feet of impervious surface.
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Figure 9. Proposed hydrology
4.3 Part C - Performance Standards
Flow Control Standard
Per the City’s flow control application map, the project site is within an area where a peak
rate flow control standard is used against existing site conditions. Therefore, peak flow
rate from the proposed site for the 2-year, 10-year, and 100-year events must be at or
below the peak flow rate for those events for the existing site conditions. Given the
downstream conditions described in Section 3, no additional flow control or mitigation is
needed for this project.
LID Performance Standard
To meet Minimum Requirement #9, the project will meet the LID performance standard
which is defined as having stormwater discharges shall match developed discharge
durations to pre-developed durations for the range of pre-developed discharge rates from
8% of the 2-year peak flow to 50% of the 2-year peak flow—assuming historical
(forested) site conditions as the predeveloped condition.
4.4 Part D - Flow Control System
Per the City’s flow control application map, the project site is within an area where a peak
rate flow control standard is used against existing site conditions.
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A Western Washington Hydrology Model (WWHM) model was used to determine the
peak flow rates generated given the existing site and the proposed site. As only the
Finished Product Storage area will continue to drain to the stormwater system once the
project is completed, this is the only area included in the proposed condition in the
WWHM model and is all impervious area. In the existing model, the entire site is included
using the current land cover.
The peak flow rate results from the WWHM model are summarized in Figure 10 which
shows that the peak flow rate control standard is met by keeping the peak discharge
rates for the 2-, 10-, and 100-year return periods below the existing peak discharge
rates.
Figure 10. WWHM peak flow rate results
The WWHM model was used to determine of the LID duration standard was met to fulfill
Core Requirement #9. The LID duration results from the WWHM model are summarized
in Figure 11 which shows that the LID duration standard is met.
Figure 11. WWHM LID duration results
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4.5 Part E - Water Quality System
All pollution generation impervious surfaces will drain to catch basins that are connected
to the sanitary sewer system which conveys to South Plant for treatment.
5 Conveyance System Analysis and Design
Conveyance piping was sized to convey the 25-year, 24-hour design storm calculated
using the rational method as outlined in Section 3.2.1 of the SWDM. The manning’s
equation was used to verify that the capacity of a full flowing pipe exceeds the flow
generated by the 25-year, 24-hour design storm.
The calculations are shown in Figure 12. The rational method calculated a peak 25-year
flow rate of 1.41 cubic feet per second (cfs). A 12-inch pipe placed at a slope of 0.0056
feet per foot has a capacity of 2.48 cfs which exceeds the calculated 1.44 cfs peak flow
rate. 12-inch pipes will be used to connect the proposed catch basins to the sanitary
sewer system.
Figure 12. Conveyance calculations
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6 Special Reports and Studies
No additional special reports or studies were created as part of this project.
7 Other Permits
The following permits are being acquired for the completion of this project:
• City of Renton
o Type II Temporary Use Permit
o Civil Construction Permit / Grading Permit
o Critical Areas Permit
• Puget Sound Clean Air Agency
o Notice of Construction
• King County WTD
o SEPA Environmental Checking / Threshold Determination
8 CSWPP Analysis and Design
The project will follow construction stormwater pollution prevention (CSWPP) standards
as outlined in Appendix D of the SWDM.
A CSWPP Plan with its associated erosion sediment control (ESC) plan and stormwater
pollution prevention and spill control (SWPPS) plan are included in Appendix A.
8.1 Part A – ESC Plan Analysis and Design
Site specific details for temporary erosion and sediment control (ESC) that will be used
during construction are included in Appendix A. In addition to the site specific plans, the
following general Best Management Practices (BMPs) for ESC will be used in
accordance with Appendix D of the SWDM.
• Marking clearing limits - Prior to any site clearing or grading, areas to remain
undisturbed during project construction shall be delineated and physically marked on
the project site.
• Cover measures - Temporary and permanent cover measures shall be provided
when necessary to protect disturbed areas. The intent of these measures is to
prevent erosion by having as much area as possible covered during any period of
precipitation.
• Perimeter protection - Perimeter protection to filter sediment from sheet flow shall be
provided downstream of all disturbed areas prior to upslope grading.
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• Traffic area stabilization - Unsurfaced entrances, roads, and parking areas used by
construction traffic shall be stabilized to minimize erosion and tracking of sediment
offsite.
• Sediment retention - Surface water collected from all disturbed areas of the site shall
be routed through a sediment pond or trap prior to release from the site, except those
areas at the perimeter of the site small enough to be treated solely with perimeter
protection. Sediment retention facilities shall be installed prior to grading any
contributing area.
• Surface water collection - Surface water collection measures (e.g., ditches, berms,
etc.) shall be installed to intercept all surface water from disturbed areas, convey it to
a sediment pond or trap, and discharge it downstream of any disturbed areas. Areas
at the perimeter of the site, which are small enough to be treated solely with
perimeter protection, do not require surface water collection. Surface water collection
measures shall be installed concurrently with or immediately following rough grading
and shall be designed, constructed, and stabilized as needed to minimize erosion.
• Dewatering control – Interception of the water table is not expected to occur as part
of this project; therefore, dewatering activities are not planned to occur. However, if
dewatering were to take place, the water resulting from construction site de-watering
activities must be treated prior to discharge or disposed of as specified.
• Dust control - Preventative measures to minimize wind transport of soil shall be
implemented when a traffic hazard may be created or when sediment transported by
wind is likely to be deposited in water resources.
• Flow control - Surface water from disturbed areas must be routed through the
project's onsite flow control facility or other provisions must be made to prevent
increases in the existing site conditions 2-year and 10-year runoff peaks discharging
from the project site during construction.
• Control pollutants - Stormwater pollution prevention (SWPPS) measures are
required to prevent, reduce, or eliminate the discharge of pollutants to onsite or
adjacent stormwater systems or watercourses from construction-related activities
such as materials delivery and storage, onsite equipment fueling and maintenance,
demolition of existing buildings and disposition of demolition materials and other
waste, and concrete handling, washout and disposal.
• Protecting existing and proposed flow control BMPs - Sedimentation and soil
compaction reduce the infiltration capacity of native and engineered soils. Protection
measures shall be applied/installed and maintained so as to prevent adverse impacts
to existing flow control BMPs and areas of proposed flow control BMPs for the
project. Adverse impacts can prompt the requirement to restore or replace affected
BMPs.
• Maintain protective BMPs - Protection measures shall be maintained to assure
continued performance of their intended function, to prevent adverse impacts to
existing flow control BMPs and areas of proposed flow control BMPs, and protect
other disturbed areas of the project.
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• Manage the project - Coordination and timing of site development activities relative
to ESC concerns, and timely inspection, maintenance and update of protective
measures are necessary to effectively manage the project and assure the success of
protective ESC and SWPPS design and implementation.
8.2 Part B – SWPPS Plan Design
The general Best Management Practices (BMPs) outlined in the King County Stormwater
Pollution Prevention Manual for the following activities to prevent the contribution of
pollutants to surface and stormwater during construction will be followed.
• A-27: Clearing, Grading, and Preparation of Land for Small Construction Projects
• A-28: Demolition of Buildings
• A-29: Building Repair, Remodeling, and Construction
The general BMPs outlined in the King County Stormwater Pollution Prevention Manual
for the following activities to prevent the contribution of pollutants to surface and
stormwater after construction will be followed.
• A-1: Required Best Management Practices for all Properties with Commercial
Activities
• A-24: Commercial composting
Additionally, some of ESC BMPs described in Section 8.1 will also be utilized for
SWPPS.
9 Bond Quantities, Facility Summaries, and
Declaration of Covenant
A preliminary Site Improvement Bond Quantities Worksheet is included. While the project
resides on a parcel for a public entity (King County Department of Natural Resources &
Parks Wastewater Treatment Division), cost items associated with the project have been
entered into the Site Improvement Bond Quantities Worksheet as a “Private
Improvement” as these will be maintained by King County and not the City of Renton.
The site does not install a flow control or water quality treatment facility (and instead
discharges a portion of the site to the sanitary sewer). Therefore a Flow Control and
Water Quality Facility Summary Sheet and Sketch is not included.
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10 Operations and Maintenance Manual
Stormwater features of this project include catch basins and conveyance pipes. The
following tables outline operation and maintenance (O&M) requirements for the various
stormwater features that are a part of the project.
Table 4. Conveyance pipe maintenance
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Table 5. Grounds maintenance
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Table 6. Catch basin and manhole maintenance
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Appendix A. Erosion Sediment Control Plan
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WKL
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DESIGNED/DRAWN:
PROJECT ENGINEER:
PROJECT ACCEPTANCE:
DESIGN APPROVAL:
CONTRACT NO:
DRAWING NO:SCALE:
PROJECT FILE NO:
DEPARTMENT OF NATURAL RESOURCES & PARKSWASTEWATER TREATMENT DIVISION
DATE:
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KING COUNTY SOUTH WASTEWATER TREATMENT PLANT
LOOP PILOT COMPOST FACILITY
#C1136470
CALL 24 HOURS BEFORE YOU DIG: 811
INFORMATION ONLY
PRELIMINARY ISSUE DRAWING
EROSION CONTROL PLAN
AS NOTED
#0
CONSTRUCTION NOTES:
SILT CONTROL FENCE PER DETAIL C-40001-3.
TEMPORARY CONSTRUCTION ENTRANCE PER
DETAIL C-40001-1.
CATCH BASIN PROTECTION PER DETAIL C-40001-2.
LIMITS OF CONSTRUCTION
PROTECT EXISTING STAIRWELL.
2
3
NOTES:
1.THIS DRAWING WAS PREPARED TO OBTAIN PERMITS ANDREPRESENTS A TESC AND TEMPORARY DRAINAGE SYSTEM THATCOULD BE PROVIDED BY THE CONTRACTOR DURING THE INITIALPHASE OF WORK.
2.THE CONTRACTOR IS RESPONSIBLE FOR DEVELOPING ANDIMPLEMENTING A CONTRACTOR-PREPARED CONSTRUCTIONSTORMWATER POLLUTION PREVENTION PLAN (CSWPPP) WHICHINCLUDES AN EROSION AND SEDIMENT CONTROL PLAN (CESCP) INACCORDANCE WITH SPECIFICATION SECTION 31 25 00. THE PLAN ISTO BE COMPLETE AND IMPLEMENTED PRIOR TO ANY GROUND
DISTURBING ACTIVITY.
3.WHEN POSSIBLE, CONTRACTOR TO PROVIDE TEMPORARY SUMPSWITHIN THE WORK AREA FOR STORAGE OR FROM WHICH PUMPINGCAN OPTIMIZE CONTROL OF RUNOFF FROM SEDIMENT GENERATINGAREAS.
4.CONSTRUCTION RUNOFF SHALL BE CONTROLLED AND CONVEYEDAND NOT BE ALLOWED TO ENTER BEYOND THE CONSTRUCTIONLIMITS AT ANY TIME, UNLESS AUTHORIZED IN WRITING BY THEPROJECT REPRESENTATIVE.
5.CESCP SHALL PROVIDE FOR INSTALLATION AND MAINTENANCE OFCATCH BASIN INSERTS IN ALL EXISTING AND NEW CATCH BASINSAND MH THAT CAPTURE CONSTRUCTION RUNOFF.
6.SPOILS & STAGING AREA TO BE GRADED TO NATURAL GROUND ANDVEGETATION ESTABLISHED PRIOR TO ACCEPTANCE.
7.EXISTING CONTOUR INFORMATION SHOWN IS AT ONE (1) FOOTINTERVALS.
8.ON-SITE DUST CONTROL SHALL BE IN ACCORDANCE WITH SECTIOND.3.8 OF KING COUNTY'S SURFACE WATER DESIGN MANUAL.
9.CONTRACTOR WILL CLEAN-UP SPOILS THAT MIGRATE ONTO THEROADS A MINIMUM OF ONCE DAILY.
10.ANY DIRT, MUD, ROCK, DEBRIS, ETC. THAT IS SPILLED TRACKED, OROTHERWISE DEPOSITED ON ANY EXISTING PAVED STREETS SHALLBE CLEANED UP IMMEDIATELY.
5
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Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
EXISTIN
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AS PER KING COUNTY ROAD STANDARDS,DRIVEWAYS SHALL BE PAVED TO THEEDGE OF R-O-W PRIOR TO INSTALLATIONOF THE CONSTRUCTION ENTRANCE TOAVOID DAMAGING OF THE ROADWAY.
IT IS RECOMMENDED THAT THEENTRANCE BE CROWNED SO THATRUNOFF DRAINS OFF THE PAD.
PROVIDE FULL WIDTH OFINGRESS/EGRESS AREA.
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10'-25'
SPACING VARIES DEPENDINGON SOIL TYPE AND SLOPESTEEPNESS
MIN 4"x4" TRENCH
2"x2" WOOD POSTS, STEELFENCE POSTS, OR EQUIVALENT
COMPOST SOCKS
OVERFLOW (TO BYPASSPEAK STORM VOLUMES)
TO PREVENT SEDIMENT FROM ENTERING STORMDRAINAGE SYSTEMS PRIOR TO PERMANENTSTABILIZATION OF THE DISTURBED AREA.
REASON:
PRE-MANUFACTUREDCATCH BASIN ORINLET INSERT
INSERTS SHOULD BE INSPECTED DAILY AND AFTERSIGNIFICANT RAINFALL. CLEAN OR REPLACE INSERTSWHEN HALF OF THE TRAP IS FILLED WITH SEDIMENT.
NOTE: SEDIMENTATIONTRAPS SHALL BECLEANED AT REGULAR
INTERVALS AND SHALLREMAIN IN PLACE UNTILCONSTRUCTION ISCOMPLETE.
1
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DESIGNED/DRAWN:
PROJECT ENGINEER:
PROJECT ACCEPTANCE:
DESIGN APPROVAL:
CONTRACT NO:
DRAWING NO:SCALE:
PROJECT FILE NO:
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KING COUNTY SOUTH WASTEWATER TREATMENT PLANT
LOOP PILOT COMPOST FACILITY
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CALL 24 HOURS BEFORE YOU DIG: 811
INFORMATION ONLY
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60% DESIGN
EROSION SEDIMENT
CONTROL PLAN
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Tier 2 Temporary
Use Permit Review Figure 3. Site Piping Plan
EXHIBIT 11
RECEIVED
Clark Close 04/19/2021
PLANNING DIVISION
2021-03-12: Per Technical Information Report
(TIR) dated March 10, 2021, proposed SS
pipelines are 12" (not 6" as shown on this 60%
design drawing).
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Tier 2 Temporary
Use Permit Review Figure 3. Sanitary Sewer Plan
and Profile 1 of 2
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Tier 2 Temporary
Use Permit Review Figure 3. Sanitary Sewer Plan
and Profile 2 of 2
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
400 North 34th Street Suite 100 PO Box 300303 Seattle, Washington 98103-8636 206 632-8020 Fax 206 695-6777
www.shannonwilson.com
March 26, 2021
Mr. Jeff Hansen, PE
HDR Engineering, Inc.
905 Plum Street SE, Suite 200, Town Square 3
Olympia, WA 98501
RE: KING COUNTY COMPOST FACILITY GEOLOGIC HAZARD REVIEW,
RENTON, WASHINGTON
Dear Mr. Hansen:
HDR Engineering, Inc. requested Shannon & Wilson provide geotechnical
recommendations related to mapped steep slope and coal mine hazard at the proposed King
County Biosolids Compost Facility (Project) at the King County South Treatment Plant
located at 1200 Monster Road Southwest in Renton Washington. This letter, which includes
the requested geotechnical recommendations, was prepared for the exclusive use of HDR
and their representatives for the Project. Our assessment, interpretations, conclusions, and
recommendations are based on:
The limitations of our approved scope, schedule, and budget described in an email from
HDR dated March 2, 2021, and an existing King County Contract (No. E00548E18) for
the King County Wastewater Treatment Division Resource Recovery Work Order No. 5
dated March 24, 2021.
Our understanding of the Project and information provided by HDR on March 2, 2021.
Conditions we observed during our visit site on March 18, 2021, and our understanding
of information that you provided prior to and during that visit.
Our previous experience near the Project site from the King County South Treatment
Plan Biogas and Heat Systems Improvements Project in 2017.
Review of publicly available documents.
PROJECT UNDERSTANDING
Shannon & Wilson understands the Project will consist of constructing a pilot biosolid
compost facility within the approximate footprint of a former pilot biogas facility. Based on
our correspondence with HDR, the existing pilot biogas facility will be removed and the
replacement compost facility will generally consist of a paved surface with cells for the
EXHIBIT 12
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Mr. Jeff Hansen, PE HDR Engineering, Inc. March 26, 2021 Page 2 of 6
106905-001-L1/wp/lkn 106905-001
various stages of compost, contained by precast concrete blocks (e.g., ecology blocks),
stacked one to two blocks high.
SITE DESCRIPTION
The Project site is located adjacent to a steep slope as defined by the City of Renton Critical
Areas Regulation No. 4‐3‐050. Cells for the Screening Area, Curing Area, Compost Bunker,
and Biofilter will be located near the top of the north facing slope. As shown in Figure 1, the
slope is identified to be approximately 15% to more than 40%. Based on the Paving and Site
Grading Plan (HDR, 2021) and our site visit, the slope appears to be inclined at
approximately 40% and is up to approximately 12.5 feet tall. The steeper portion of the
mapped steep slope area is a contouring artifact associated of a concrete structure.
The Project site is also partially within a mapped moderate coal mine hazard. We
understand the site has this designation because of its proximity to the mapped historical
coal mine. The coal mine consists of a series of mine adits extending north from the former
mine entrance near the northeast corner of the Cogeneration Building, as shown in Figure 1.
SUBSURFACE CONDITIONS
Our experience with past projects and mapped geology at this location indicates that the
following geologic units (as encountered from lower to higher elevation) are present at the
Project site: Holocene Fill, Holocene Alluvium, layers of floodplain and organic deposits,
and bedrock consisting of the Renton Formation. Based on the previous explorations
completed by Shannon & Wilson and others nearby, the Project site has encountered loose
to medium dense, silty sand with gravel; soft to stiff silt; and medium stiff, organic silt. The
location of the borings in conjunction with the soil types generally indicate that the soils are
of alluvial or lacustrine origin overlain by recent fill materials in some areas.
FIELD RECONNAISSANCE
We visited the site on March 18, 2021, to review the existing topography and document
observed surficial conditions that could indicate either evidence of slope instability or an
active hazard associated with the former coal mine. The existing slope along the north side
of the site appears to be a constructed cut to provide vehicle access to the digesters located
to the east of the site. The mapped “protected” steep slope, identified in Figure 1, is a
vertical concrete wall. The remainder of the slope is approximately 40% or less and
landscaped. During our site visit, we did not observe any indications (e.g., tension cracks,
scarps, or pistol butted trees) of instability. Our observations of the slope indicate the
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Mr. Jeff Hansen, PE HDR Engineering, Inc. March 26, 2021 Page 3 of 6
106905-001-L1/wp/lkn 106905-001
surficial soils are predominantly silty sand with no visible seepage emitted from the slope
face. Our recent observations are generally consistent with the soils observed and
documented in the historic borings.
During our visit, we also visited the Project area where the mapped coal mine hazard is
located. We did not observe any evidence of subsidence that would suggest an immediate
hazard or that conditions at the site are different than previously identified.
GEOLOGIC HAZARD REVIEW
Coal Mine Hazard
According to the reference documents linked to Renton’s COR Map geographic information
system (GIS) mapping website (City of Renton, 2021a), there was previous coal mining
activity below the Project site. Based on the publicly available information, this mine
operation belonged to the Diamond Coal Company. No other information is available.
Based on the relatively specific mapped location of the adits associated with the Diamond
Coal Company mine, it is our opinion that the mine adits do not extend beneath the
footprint of the proposed pilot biosolid compost facility.
During our 2016 subsurface investigation program for the Biogas and Heat System
Improvements (Shannon & Wilson, 2017a and 2017b), we advanced two borings to depths of
about 91.5 to 121.5 feet below ground surface (bgs) at the location of the proposed Heat and
Energy Recovery building, north of the Project site, as shown in Figure 1 (Shannon &
Wilson, 2017a and 2017b). Subsurface information obtained from the explorations indicated
that the Project site is underlain by sandstone bedrock consisting of the Renton Formation at
depths ranging from approximately 80 to 111 feet bgs. This formation is known for
containing coal beds, some of which that were mined. The soils above the bedrock consist
of alluvial sediments that were not associated with coal mine operations.
Previous subsurface explorations, including borings and test pits by others, also did not
locate coal mining evidence at the facility (Shannon & Wilson, 2017a and 2017b). In our
opinion, there is no subsurface or surface evidence of past mining activity at the proposed
pilot biosolid compost facility and there is low probability that construction of the proposed
Project is at risk of coal mine hazards such as subsidence. Also, given our understanding
that the proposed Project will largely consist of paving and stacked ecology blocks, we do
not anticipate coal mine hazards to be a design issue that require mitigation.
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Mr. Jeff Hansen, PE HDR Engineering, Inc. March 26, 2021 Page 4 of 6
106905-001-L1/wp/lkn 106905-001
Steep Slope Hazards
The proposed footprint of the Project site is at the crest of a Regulated Slope as identified by
Renton’s COR Map GIS mapping website (City of Renton, 2021a). Based on the Paving and
Site Grading Plan (HDR, 2021), the slope is between the approximate elevations of 114 to
127 feet. In our opinion, the existing north‐facing slope should be classified as a sensitive
slope under the Renton Municipal Code 4‐3‐050G based on the inclination (City of Renton,
2021b). Also, consistent with the Renton Municipal Code 4‐3‐050G, it is our opinion that a
setback buffer is not required. We anticipate the setback distance from the top of the slope
based on the 60% Design Drawings is sufficient to avoid excessive surcharge on the slope.
RECOMMENDATIONS AND CONCLUSIONS
In our opinion, the development of the King County facility at this location, where the
roadway is below the above‐mentioned critical slope, is likely a cut‐slope created to provide
access to other parts of the facility. The proposed setback buffer and development of the
biosolids compost facility at the top of the slope, in our opinion, will not impact the cut
slope stability. We believe the mapped coal mine hazards do not present a design issue or
hazard that could impact the Project.
For purposes of our recommendations and conclusions, it was necessary for us to assume
that the results of the past explorations are representative of conditions throughout the
Project site. However, subsurface conditions should be expected to vary. We may need to
revise our recommendations during construction if different conditions are encountered.
Our recommendations and conclusions are based on limited past explorations and site visit
on March 18, 2021. Additional explorations may be required to develop final design
recommendations for this Project.
The subsurface conditions are interpreted from materials observed in historic explorations
completed for King County projects at the South Wastewater Treatment Plant. Variations
between the interpretation shown and actual conditions will exist.
We have prepared our recommendations for the construction of the pilot compost facility
and considering the Project configuration as described in Drawings SP220‐G‐00002, SP220‐
C‐00002, and SP220‐C‐10002 prepared by HDR. When the owner or designer develops
additional information about final ecology block wall configurations or other factors, the
recommendations presented herein may need to be revised. Shannon & Wilson should be
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Mr. Jeff Hansen, PE HDR Engineering, Inc. March 26, 2021 Page 5 of 6
106905-001-L1/wp/lkn 106905-001
made aware of the revised or additional information so that we can evaluate our
recommendations for applicability.
We recommend that during construction of the pilot biosolids compost facility a
representative from Shannon & Wilson complete a weekly site visit to observe the
conditions of the slope and Project site. This will allow Shannon & Wilson to compare the
conditions exposed during construction to our observations on March 18, 2021, and the
interpreted conditions from the past subsurface explorations completed within the King
County facility. These visits will ensure our conclusions are consistent with the conditions
encountered during construction.
LIMITATIONS
Our scope of services did not include:
Evaluating the presence or absence of wetlands, cultural resources, or hazardous
materials at or around the site.
Performing subsurface explorations at the site.
Performing geotechnical engineering analyses for slope stability.
Our recommendations and conclusions rely on part upon explorations performed by others.
We did not review samples and cannot confirm that the explorations performed by others
are representative of the site conditions. We also relied upon the City of Renton mapping
data in our evaluation of coal mine hazards. If conditions different from those described
herein are encountered during construction, we should review our description of the
subsurface conditions and reconsider our conclusions and recommendations.
This letter should not be used without our approval if any of the following occur:
Conditions change due to natural forces or human activity under, at, or adjacent to the
site.
Assumptions stated in this letter have changed.
Project details change or new information becomes available such that our assessment,
conclusions, and recommendations may be affected.
If the site ownership or land use has changed.
A substantial lapse of time has passed since the issuance of this letter.
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
106905-001-L1-Ref/wp/lkn 106905-001
REFERENCES
City of Renton, 2021a, City of Renton COR Maps, Interactive online GIS Mapping
Application, City of Renton, available:
https://maps.rentonwa.gov/Html5viewer/Index.html?viewer=cormaps
City of Renton, 2021b, Renton Municipal Code: A Codification of the General Ordinances of
the City of Renton, Washington, available:
https://www.codepublishing.com/WA/Renton/
HDR Engineering, Inc., 2021, King County South Wastewater Treatment Plant Loop Pilot
Compost Facility, Drawings SP220-G-00002, SP220-C-00002, SP220-C-10002.
Drawings prepared by HDR Engineering, Inc. for King County Department of
Natural Resources and Parks, Wastewater Treatment Division, King County,
Washington.
Shannon & Wilson, 2017a, Geotechnical Report Addendum, Biogas and Heat Systems
Improvement Projects, King County South Treatment Plant, Renton, Washington:
Report prepared by Shannon & Wilson, Inc. for Brown and Caldwell, Seattle,
Washington.
Shannon & Wilson, 2017b, Draft Geotechnical Report, King County South Treatment Plant,
Biogas and Heat Systems Improvements, Renton, Washington: Report prepared by
Shannon & Wilson, Inc. for Brown and Caldwell, Seattle, Washington.
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Page 1 of 2 1/2021
Attachment to and part of Report: 106905-001
Date: March 26, 2021
To: Mr. Jeff Hansen, PE
HDR Engineering, Inc.
Important Information About Your
Geotechnical/Environmental Report
CONSULTING SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES AND FOR SPECIFIC CLIENTS.
Consultants prepare reports to meet the specific needs of specific individuals. A report prepared for a civil
engineer may not be adequate for a construction contractor or even another civil engineer. Unless indicated
otherwise, your consultant prepared your report expressly for you and expressly for the purposes you indicated.
No one other than you should apply this report for its intended purpose without first conferring with the
consultant. No party should apply this report for any purpose other than that originally contemplated without
first conferring with the consultant.
THE CONSULTANT’S REPORT IS BASED ON PROJECT-SPECIFIC FACTORS.
A geotechnical/environmental report is based on a subsurface exploration plan designed to consider a unique set
of project-specific factors. Depending on the project, these may include the general nature of the structure and
property involved; its size and configuration; its historical use and practice; the location of the structure on the
site and its orientation; other improvements such as access roads, parking lots, and underground utilities; and the
additional risk created by scope-of-service limitations imposed by the client. To help avoid costly problems, ask
the consultant to evaluate how any factors that change subsequent to the date of the report may affect the
recommendations. Unless your consultant indicates otherwise, your report should not be used (1) when the
nature of the proposed project is changed (for example, if an office building will be erected instead of a parking
garage, or if a refrigerated warehouse will be built instead of an unrefrigerated one, or chemicals are discovered
on or near the site); (2) when the size, elevation, or configuration of the proposed project is altered; (3) when the
location or orientation of the proposed project is modified; (4) when there is a change of ownership; or (5) for
application to an adjacent site. Consultants cannot accept responsibility for problems that may occur if they are
not consulted after factors that were considered in the development of the report have changed.
SUBSURFACE CONDITIONS CAN CHANGE.
Subsurface conditions may be affected as a result of natural processes or human activity. Because a
geotechnical/environmental report is based on conditions that existed at the time of subsurface exploration,
construction decisions should not be based on a report whose adequacy may have been affected by time. Ask the
consultant to advise if additional tests are desirable before construction starts; for example, groundwater
conditions commonly vary seasonally.
Construction operations at or adjacent to the site and natural events such as floods, earthquakes, or groundwater
fluctuations may also affect subsurface conditions and, thus, the continuing adequacy of a
geotechnical/environmental report. The consultant should be kept apprised of any such events and should be
consulted to determine if additional tests are necessary.
MOST RECOMMENDATIONS ARE PROFESSIONAL JUDGMENTS.
Site exploration and testing identifies actual surface and subsurface conditions only at those points where
samples are taken. The data were extrapolated by your consultant, who then applied judgment to render an
opinion about overall subsurface conditions. The actual interface between materials may be far more gradual or
abrupt than your report indicates. Actual conditions in areas not sampled may differ from those predicted in
your report. While nothing can be done to prevent such situations, you and your consultant can work together to
help reduce their impacts. Retaining your consultant to observe subsurface construction operations can be
particularly beneficial in this respect.
RECEIVED
Clark Close 04/19/2021
PLANNING DIVISION
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
Page 2 of 2 1/2021
A REPORT’S CONCLUSIONS ARE PRELIMINARY.
The conclusions contained in your consultant’s report are preliminary, because they must be based on the
assumption that conditions revealed through selective exploratory sampling are indicative of actual conditions
throughout a site. Actual subsurface conditions can be discerned only during earthwork; therefore, you should
retain your consultant to observe actual conditions and to provide conclusions. Only the consultant who
prepared the report is fully familiar with the background information needed to determine whether or not the
report’s recommendations based on those conclusions are valid and whether or not the contractor is abiding by
applicable recommendations. The consultant who developed your report cannot assume responsibility or
liability for the adequacy of the report’s recommendations if another party is retained to observe construction.
THE CONSULTANT’S REPORT IS SUBJECT TO MISINTERPRETATION.
Costly problems can occur when other design professionals develop their plans based on misinterpretation of a
geotechnical/environmental report. To help avoid these problems, the consultant should be retained to work
with other project design professionals to explain relevant geotechnical, geological, hydrogeological, and
environmental findings, and to review the adequacy of their plans and specifications relative to these issues.
BORING LOGS AND/OR MONITORING WELL DATA SHOULD NOT BE SEPARATED FROM THE
REPORT.
Final boring logs developed by the consultant are based upon interpretation of field logs (assembled by site
personnel), field test results, and laboratory and/or office evaluation of field samples and data. Only final boring
logs and data are customarily included in geotechnical/environmental reports. These final logs should not, under
any circumstances, be redrawn for inclusion in architectural or other design drawings, because drafters may
commit errors or omissions in the transfer process.
To reduce the likelihood of boring log or monitoring well misinterpretation, contractors should be given ready
access to the complete geotechnical engineering/environmental report prepared or authorized for their use. If
access is provided only to the report prepared for you, you should advise contractors of the report’s limitations,
assuming that a contractor was not one of the specific persons for whom the report was prepared, and that
developing construction cost estimates was not one of the specific purposes for which it was prepared. While a
contractor may gain important knowledge from a report prepared for another party, the contractor should
discuss the report with your consultant and perform the additional or alternative work believed necessary to
obtain the data specifically appropriate for construction cost estimating purposes. Some clients hold the mistaken
impression that simply disclaiming responsibility for the accuracy of subsurface information always insulates
them from attendant liability. Providing the best available information to contractors helps prevent costly
construction problems and the adversarial attitudes that aggravate them to a disproportionate scale.
READ RESPONSIBILITY CLAUSES CLOSELY.
Because geotechnical/environmental engineering is based extensively on judgment and opinion, it is far less exact
than other design disciplines. This situation has resulted in wholly unwarranted claims being lodged against
consultants. To help prevent this problem, consultants have developed a number of clauses for use in their
contracts, reports, and other documents. These responsibility clauses are not exculpatory clauses designed to
transfer the consultant’s liabilities to other parties; rather, they are definitive clauses that identify where the
consultant’s responsibilities begin and end. Their use helps all parties involved recognize their individual
responsibilities and take appropriate action. Some of these definitive clauses are likely to appear in your report,
and you are encouraged to read them closely. Your consultant will be pleased to give full and frank answers to
your questions.
The preceding paragraphs are based on information provided by the ASFE/Association of Engineering Firms
Practicing in the Geosciences, Silver Spring, Maryland
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
King County WTD -1- Loop Compost Pilot Project
Loop Compost Pilot Project Request for City of Renton Temporary Use Permit Construction Mitigation Description
King County Wastewater Treatment Division (WTD) is submitting a request for a Temporary Use Permit (TUP) to construct and operate the Loop® Compost Pilot Project (project) at the King County South Treatment Plant in Renton.
Proposed Construction Dates (begin and end dates)
It is anticipated that construction of the project will begin in early spring of 2022, and be complete in early summer 2022, with operation commencing one to three months after final acceptance.
Hours and Days of Operations
Construction timing will be determined by the selected contractor. It is anticipated that construction will occur Monday through Friday, from 7 a.m. to 4 p.m.; no weekend or late-night work is anticipated.
Proposed Hauling/Transportation Routes
The hauling/transportation route to the site is anticipated to be from Interstate 405 to northbound Interurban Ave S (State Route 181), then east on SW Grady Way, then north on Monster Road SW, turning east into the main entrance to the South Treatment Plant. The haul route could change depending on the source of the materials needed for construction.
Measures to be Implemented to Minimize Dust, Traffic and Transportation Impacts
During construction, Best Management Practices (BMPs) will be implemented to control dust, erosion and noise. Types of BMPs that will be used may include street sweeping, watering exposed soil surfaces,
and covering soil stockpiles to help minimize the amount of fugitive dust and particulate pollution to the surrounding areas. Erosion control measures would also be implemented during construction and may include stabilization of construction entrances and wheel washes to minimize tracking of sediment onto
the roadway and restoration of disturbed areas by repaving or replanting following construction. Measures to reduce noise may include temporary noise barriers and effective equipment mufflers and shutting off engines when not in use. Construction equipment-related emissions will be reduced by requiring proper
maintenance of equipment, using electrically powered equipment where practical, and avoiding prolonged idling of vehicles and equipment. No impacts are anticipated to traffic on public rights-of-way during construction; therefore, a traffic control plan is not included as part of the project.
Project construction will require delivery of equipment and materials by truck, generating approximately 275 truck trips total during construction. Given the existing vehicular activity on the South Treatment Plant property, including daily biosolids hauling, and the industrial nature of the project vicinity, there will be negligible changes in vehicular traffic as a result of construction activities. Therefore, construction-related mitigation measures are not proposed.
EXHIBIT 13
RECEIVED
Clark Close 04/19/2021
PLANNING DIVISION
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
DEPARTMENT OF COMMUNITY
AND ECONOMIC DEVELOPMENT
17
H:\CED\Data\Forms-Templates\Self-Help Handouts\Planning\Temporary Use Tier 2.doc Rev: 09/2019
ABATEMENT AGREEMENT
TEMPORARY USE
Planning Division
1055 South Grady Way, Renton, WA 98057
Phone: 425-430-7294 | www.rentonwa.gov
I, being the Applicant for the Temporary Use Permit at the
Location of:
Hereby authorize the City of Renton to summarily eliminate the Temporary Use and all evidence of the use if it has
not been removed as required by the terms of the permit. I also agree to reimburse the City for any expense
incurred in abating this Temporary Use.
Signature:
Print Name:
Date:
STATE OF WASHINGTON )
) SS
COUNTY OF KING )
I certify that I know or have satisfactory evidence that signed this instrument
and acknowledged it to be his/her/their free and voluntary act for the uses and purposes mentioned in the
instrument.
Dated:
Notary Public in and for the State of Washington
Notary (Print):
My appointment expires:
Christopher Dew
1200 Monster Road SW, Renton, WA 98055
Christopher Dew
EXHIBIT 14
RECEIVED
Clark Close 04/19/2021
PLANNING DIVISION
4-23-2021
Trevor J. Carr
3-31-2021
Christopher Dew
March 31, 2021
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
DEPARTMENT OF COMMUNITY
AND ECONOMIC DEVELOPMENT
Page 1 of 2 LUA21-000141
ADVISORY NOTES TO APPLICANT
The following notes are supplemental information provided in conjunction with the administrative land use
action. Because these notes are provided as information only, they are not subject to the appeal process for
the land use action.
Planning:
(Contact: Clark Close, 425-430-7289, cclose@rentonwa.gov)
1. RMC section 4-4-030.C.2 limits haul hours between 8:30 am to 3:30 pm, Monday through Friday unless
otherwise approved by the Development Services Division.
2. Commercial, and other nonresidential construction activities shall be restricted to the hours between
seven o’clock (7:00) a.m. and eight o’clock (8:00) p.m., Monday through Friday. Work on Saturdays shall
be restricted to the hours between nine o’clock (9:00) a.m. and eight o’clock (8:00) p.m. No work shall
be permitted on Sundays.
3. Within thirty (30) days of completion of grading work, the applicant shall hydroseed or plant an
appropriate ground cover over any portion of the site that is graded or cleared of vegetation and where
no further construction work will occur within ninety (90) days. Alternative measures such as mulch,
sodding, or plastic covering as specified in the current King County Surface Water Management Design
Manual as adopted by the City of Renton may be proposed between the dates of November 1st and
March 31st of each year. The Development Services Division’s approval of this work is required prior to
final inspection and approval of the permit.
4. A National Permit Discharge Elimination System (NPDES) permit is required when more than one acre is
being cleared.
5. The applicant may not fill, excavate, stack or store any equipment, dispose of any materials, supplies or
fluids, operate any equipment, install impervious surfaces, or compact the earth in any way within the
area defined by the drip line of any tree to be retained.
6. The applicant shall erect and maintain six foot (6') high chain link temporary construction fencing around
the drip lines of all retained trees, or along the perimeter of a stand of retained trees. Placards shall be
placed on fencing every fifty feet (50') indicating the words, “NO TRESPASSING – Protected Trees” or on
each side of the fencing if less than fifty feet (50'). Site access to individually protected trees or groups
of trees shall be fenced and signed. Individual trees shall be fenced on four (4) sides. In addition, the
applicant shall provide supervision whenever equipment or trucks are moving near trees.
7. This permit is shall comply with the Bald and Golden Eagle Protection Act. The permitted is responsible
for adhering to the U.S. Fish and Wildlife Service National Bald Eagle Management Guidelines (2007) and
/or your U.S. Fish and Wildlife Service permit.
Development Engineering:
(Contact: Jonathan Chavez, 425-430-7288, jchavez@rentonwa.gov)
1. See Attached Development Engineering Memo dated May 12, 2021.
Fire Authority:
(Contact: Corey Thomas, 425-276-9582, cthomas@rentonrfa.org)
1. No comments at this time.
Technical Services:
(Contact: Amanda Askren, 425-430-7369, aaskren@rentonwa.gov)
EXHIBIT 15
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ADVISORY NOTES TO APPLICANT
Page 2 of 2 LUA21-000141
1. No comments at this time.
Community Services:
(Contact: Leslie Betlach, 425-430-6619, lbetlach@rentonwa.gov)
1. No comments at this time.
Police:
(Contact: Cyndie Morris, 425-430-7521, cmorris@rentonwa.gov)
1. No comments at this time.
Building:
(Contact: Rob Shuey, 425-430-7290, rshuey@rentonwa.gov)
1. Recommendations of the geotechnical report must be followed as a condition of building permits.
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DEPARTMENT OF COMMUNITY
AND ECONOMIC DEVELOPMENT
M E M O R A N D U M
DATE: May 12, 2021
TO: Clark Close, Planning
FROM: Jonathan Chavez, Development Engineering
SUBJECT: Loop Pilot Compost Facility
1200 Monster Road SW
LUA21-000141
NOTE: The applicant is cautioned that information contained in this summary is preliminary and non-
binding and may be subject to modification and/or concurrence by official City decision-makers. Review
comments may also need to be revised based on site planning and other design changes required by
City staff or made by the applicant.
I have completed a preliminary review for the above-referenced proposal located at parcel(s)
2423049006. The following comments are based on the Land Use Application submittal made to the City
of Renton by the applicant:
WATER
1. Domestic water service to the King County Renton Wastewater Treatment Plant Facility is being
provided by the City of Renton through an 8-inch water meter located along the northwesterly
side of the property. There is an approved air-gap for backflow prevention measure between the
supply piping from the City’s water system to the on-site private water storage tank. Domestic
water service to all of the buildings within the treatment plant are served by a privately-owned
interior 4-inch water supply line referred to as “C1” water line.
2. Fire protection service to the plant is being provided by privately-owned interior 12-inch water
mains referred to as “Fire Line” and fire hydrants. The 12-inch water mains are connected to the
City’s water system at 2 locations, the first connection is at the west end of the SW 7th Street
Bridge and the second connection is near the access road along Monster Rd SW. There is an
approved backflow prevention assembly (RPBA) at each of the 2 connections to the City’s water
system.
3. Submit a Notice of Intent (NOI) to the Department of Ecology for the decommissioning of the
groundwater monitoring well and provide documentation of the Well Decommissioning Report
to the City. The monitoring well shall be decommissioned in accordance with WAC 173-160-381.
a. Provide proof of compliance at the Building Permit application stage of the project.
4. The applicant will not need to pay additional SDC Fees as long as their connection point is on their
private system.
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Loop Pilot Compost Facility – LUA21-000141
May 12, 2021
Page 2 of 3
5. Plans for the Building permit will need to clearly show the connections to the private lines for
domestic water as well as the sprinkler system (if required). These plans will also need to indicate
the locations of the City of Renton 12” water meter.
SEWER
1. Sewer service is provided by City of Renton.
2. There is an existing 12-inch wastewater main located in Oakesdale Ave SW (see City plan no. S-
199807).
3. Project submittal shall address odor control.
a. This must be addressed at the Building Permit application stage of the project.
4. Since the sewer line will be connected to the system within the treatment plant there will be no
SDC fees for sewer are required to be paid.
SURFACE WATER
1. A drainage review is required for projects that include
a. 2,000 square feet or more of new and/or replaced impervious surface, or
b. 7,000 square feet or more of land disturbing activity, or
c. proposes to construct or modify a drainage pipe or ditch that is 12 inches or more in
size/depth, or
d. is located in or adjacent to a flood hazard area, erosion hazard area, steep slope hazard
area, or landslide hazard area, landslide hazard drainage area, or
e. the redevelopment project proposes $100,000 or more of improvements to an existing
high-use site.
If any of the above mention criteria are met, then a drainage review meeting the current
City of Renton’s Surface Water Design Manual (RSWDM) will be required. City of Renton
standards include frontage improvements and the on-site work as one single project.
2. Based on the City’s flow control map, the site falls within the Peak Rate Flow Control Standard
area matching Existing Site Conditions and is within the Black River Drainage Basin. Refer to Figure
1.1.2.A – Flow chart to determine the type of drainage review required in the 2017 Renton Surface
Water Design Manual (RSWDM).
a. A drainage report dated March 10, 2021, was drafted by HDR and submitted with the
Land Use Application.
3. There is an existing storm water system within the property.
4. Erosion control measures to meet the City requirements shall be provided.
5. The 2021 Surface water system development fee is $0.80 per square foot of new impervious
surface, but no less than $2,000.00. Fees that are current will be charged at the time of permit
issuance. There is no storm water impact fee for replaced impervious surface area.
TRANSPORTATION
1. If proposed new construction on the site has a valuation of less than $150,000, street frontage
improvements and right of way dedication are not required. If proposed new construction on the
site has a valuation of $150,000 or more, then the installation of street frontage improvements
and right of way dedication found in comment #2 may be required to conform to the City’s
complete street standards found in RMC 4-6-060.
2. The proposed development fronts Monster Road SW along the west property line(s). Monster
Road SW is classified as a 3-lane Collector Arterial. Existing right-of-way (ROW) width is
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Page 3 of 3
approximately 60 feet. To meet the City’s complete street standards for 3-lane Error! Reference
source not found. streets, the minimum ROW is 94 feet. Per City code 4-6-060, half street
improvements shall include a pavement width of 57 feet (28.5 feet from centerline), a 0.5-foot
curb, an 8-foot planting strip, an 8-foot sidewalk, 2-foot clear space back of walk, street trees and
storm drainage improvements. The Applicant may submit a request for a street modification to
leave existing Right of Way improvements as is. Request must provide justification to why the City
should accept the modification per RMC 4-9-250.
3. Sites that generate 20 or more net new peak hour trips (either in the AM peak or PM peak) are
required to do a traffic impact analysis. The trips should be calculated based on the guidelines of
the current ITE Trip Generation Manual. Refer to the attached policy guidelines for traffic impact
analysis for guidelines. If the site generates 20 or more new peak hour trips in either AM peak or
PM peak, then applicant should contact the City to get information of the locations where traffic
analysis is required. Provide a memo that includes the trip generation number and the trip
assignment and distribution at the site accesses. Staff will review the memo and will inform the
applicant if additional study is required.
4. If it is determined that the traffic is impacted from the proposed addition, a traffic impact fee will
be assessed at the time of building permit.
GENERAL COMMENTS
1. All existing and proposed utility lines (i.e. electrical, phone, and cable services, etc.) along property
frontage or within the site must be underground. The construction of these franchise utilities must
be inspected and approved by a City of Renton inspector.
2. Adequate separation between utilities as well as other features shall be provided in accordance
with code requirements:
a. 7-ft minimum horizontal and 1-ft vertical separation between storm and other utilities is
required with the exception of water lines which require 10-ft horizontal and 1.5-ft
vertical.
b. The stormwater line should be minimum 5 feet away from any other structure or wall or
building.
c. Trench of any utility should not be in the zone of influence of the retaining wall or of the
building.
3. All civil construction permits for utility and street improvements will require separate plan
submittals. All utility plans shall confirm to the Renton Drafting Standards. A licensed Civil
Engineer shall prepare the civil plans. Please visit the Development Engineering Forms page for
the most up-to-date plan submittal requirements:
http://rentonwa.gov/business/default.aspx?id=42473
4. A landscaping plan and tree retention shall be included with the civil plan submittal. Each plan
shall be on separate sheets.
5. Additional Building Permit Applications will be required for the following:
a. Any retaining walls that exceed 4 feet in height, as defined by RMC 4-4-040.
b. Detention vaults for storm water flow control.
c. Demo of any existing structures on the project site(s).
6. Fees quoted in this document reflect the fees applicable in the year 2021 only and will be assessed
based on the fee that is current at the time of the permit application or issuance, as applicable to
the permit type. Please visit www.rentonwa.gov for the current development fee schedule.
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