HomeMy WebLinkAboutQT TIRSection 1: Project Overview
Project Location
The Quendall Terminals project is located at approximately 4350 Lake Washington Boulevard N within the City of Renton (COR) in King County, Washington. The project is located west of
Ripley Lane N and northwest of the intersection of Lake Washington Boulevard N and Ripley Lane N. The project is located in a portion of Section 29, Township 24 N, Range 5 E, W.M.
See Figure 1 in Appendix A for project location.
Proposal
The Quendall Terminals project includes construction of four mixed-use buildings with residential, office, retail, and restaurant uses.
Predeveloped Site Conditions
The existing site is vacant and is the former location of a log sorting and storage yard. The site is partially vegetated with areas of grass, shrubs, brush, and trees where the site
has been vacant for an extended amount of time. Other areas used more recently contain bare soil and debris from log yard operations. Debris piles from log yard operations are located
on the site. The site is contaminated with hazardous substances as a result of past industrial uses, including a creosote processing facility.
The site is approximately 20.3 acres in size with approximately 1,583 feet of shoreline along Lake Washington. Site slopes are generally 0-5% with localized slopes up to 2H:1V at debris
piles and up to 1H:1V at the bank of the lake. The site generally slopes gradually from east to west. Wetlands are located along and near the lakeshore on the west side of the site.
There are approximately 34,959 square feet of existing wetlands on the site.
There are no manmade stormwater conveyance, water quality, or detention facilities on the site with the exception of one small sediment pond (approximately 1,722 square feet including
rock check dams). Surface runoff currently infiltrates or surface flows west to the lake. There are no creeks or streams located on the site. See Figure 2 in Appendix A.
The Natural Resources Conservation Service (NRCS) Soils Map indicates that the site is underlain with Norma sandy loam and Bellingham silty loam. See Figure 4 in Appendix A. The site
does not lie within a 100-year floodplain per FEMA Flood Insurance Rate Map. See Figure 5 in Appendix A.
Developed Site Conditions
The proposed site improvements include a mixed-use development consisting of residential, office, retail, restaurant, and parking spaces. Proposed site slopes are not
anticipated to be steep. Piped storm drainage systems will collect and convey surface runoff from pollution-generating surfaces to water quality treatment facilities then to outfalls
at Lake Washington. Treated stormwater will discharge to wetlands adjacent to the lake during normal flows. During high flows, stormwater will bypass the water quality facilities
and wetlands, discharging directly to the lake. Where possible, surface runoff from non-pollution-generating surfaces will bypass water quality treatment facilities and will discharge
directly to the lake.
As part of this development, a site remediation/mitigation plan will be executed to prevent the exposure and spread of hazardous substances to humans and the surrounding environment.
Proposed measures to prevent environmental health hazards include minimal disturbance to contaminated soils capping of the site.
Section 2: Conditions and Requirements Summary
This report has been prepared as part of a master site plan approval process.
Conditions and Requirements Summary
See Section
Core Requirement #1
Discharge at the Natural Location
Required
2
Core Requirement #2
Offsite Analysis
Required
3
Core Requirement #3
Flow Control
Exempt
4
Core Requirement #4
Conveyance System
Required
5
Core Requirement #5
Erosion and Sediment Control
Required
8
Core Requirement #6
Maintenance and Operations
N/A
10
Core Requirement #7
Financial Guarantees and Liability
N/A
9
Core Requirement #8
Water Quality
Required
4
Special Requirement #1
Other Adopted Area-Specific Requirements
N/A
2
Special Requirement #2
Flood Hazard Area Delineation
N/A
2
Special Requirement #3
Flood Protection Facilities
N/A
2
Special Requirement #4
Source Control
Required
2
Special Requirement #5
Oil Control
N/A
2
Core Requirement #1: Discharge at the Natural Location
Stormwater runoff from the existing site either infiltrates or surface flows to Lake Washington. Stormwater runoff from the proposed improvements will be collected and conveyed by a
piped stormwater system to new outfalls at Lake Washington. Runoff from pollution-generating surfaces will be treated prior to discharge at a wetland adjacent to the lake. During
high flows, runoff from pollution-generating surfaces will bypass water quality treatment and the wetland to discharge directly to the lake. Runoff from non-pollution-generating surfaces
will bypass water quality treatment where practical. See the attached “Existing Conditions” and “Proposed Conditions” exhibits.
Special Requirement #1: Other Adopted Area-Specific Requirements
Does not apply.
Special Requirement #2: Flood Hazard Area Delineation
Does not apply.
Special Requirement #3: Flood Protection Facilities
Does not apply.
Special Requirement #4: Source Control
The proposed project will require a commercial building and commercial site development permit; therefore water quality source controls will be implemented in accordance with the King
County Stormwater Pollution Prevention Manual.
Special Requirement #5: Oil Control
The project is not anticipated to develop a high-use site; therefore oil controls are not anticipated to be required.
Section 3: Offsite Analysis
A Level 1 qualitative offsite analysis is required for this project.
Upstream Analysis
There is no upstream tributary area contributing to site stormwater runoff.
Downstream Analysis
The site location is described in the “Existing Conditions” section of this report. Runoff from the existing site surface flows to Lake Washington with no known flooding problems.
The water level in Lake Washington is maintained at the Hiram M. Chittenden Locks. Runoff from the proposed site will be collected and conveyed by a piped storm drainage system and
discharge at Lake Washington.
Section 4: Flow Control and Water Quality Facility Analysis and Design
The project is exempt from flow control requirements by the “direct discharge exemption” as defined in the 2009 KCSWDM. The project will feature a piped conveyance system of adequate
capacity that discharges directly to Lake Washington.
Runoff from pollution-generating surfaces will be collected and conveyed to water quality treatment facilities for treatment prior to discharge to Lake Washington. A water
quality design flow of 60% of the developed 2-year peak flow rate will be used in accordance with the 2009 KCSWDM. The water quality treatment facilities will discharge to wetlands
that are adjacent to the lake. Flows greater than the water quality design flow rate will bypass the water quality facilities and discharge directly to Lake Washington without entering
the wetlands.
Section 5: Conveyance System Analysis and Design
The proposed piped conveyance system will be designed to convey and contain (at minimum) the 25-year peak flow, assuming developed conditions for onsite tributary areas and existing
conditions. Potential overflow from a 100-year runoff event is not anticipated to create or aggravate a severe flooding problem or severe erosion problem. There is no upstream tributary
area draining to the site or the proposed storm drainage system. Outfalls at the discharge points of the stormwater systems shall be designed to prevent erosion at the bank of the
lake.
Section 6: Special Reports and Studies
Does not apply.
Section7: Other Permits
Does not apply.
Section 8: ESC Analysis and Design
A temporary sediment and erosion control plan designed by a professional civil engineer will be included with the project’s construction documents (to be produced in the future) conforming
to the requirements of the 2009 KCSWDM.
Section 9: Bond Quantities, Facility Summaries, and Declaration of Covenant
Not required for master site plan.
Section 10: Operations and Maintenance Manual
Not required for master site plan.