| Overall Rating | Gold |
|---|---|
| Overall Score | 65.76 |
| Liaison | Shahrzad Tehrani |
| Submission Date | Jan. 14, 2022 |
University of Washington, Bothell
IN-36: Stormwater Modeling
| Status | Score | Responsible Party |
|---|---|---|
|
0.50 / 0.50 |
"---"
indicates that no data was submitted for this field
A brief description of the methodology/tool used to calculate the percentile local or regional rainfall events for which the institution manages runoff on-site using LID practices and green infrastructure:
Historically, there have been several different Manuals/Guidelines that have been used to establish the design criteria for UWB/CC campus development. The current projects meet the 2021 City of Bothell Surface Water Design Manual, which utilizes the Western Washington Hydrologic Model (WWHM2012) to determine the sizing of LID and green infrastructure treatment of runoff. The 2021 City of Bothell Surface Water Design Manual also utilizes the 2016 King County Surface Water Design Manual. The older water quality facilities were designed to treat the mean annual runoff volumes generated by the Santa Barbara Urban Hydrograph (SBUH), using the guidance of the City of Bothell Surface Water Design Manual (which referenced the 1995 King County Surface Water Design Manual).
Based on current requirements, flow control facilities are required for mitigation of stormwater runoff from development and redevelopment projects to the Conservation Flow Control Standard (Level 2). The Level 2 standard requires post-development flows to match the historic discharge durations for 50% of the 2-year peak flow through the 50-year peak flow and to match historic 2-year and 10-year peaks assuming a forested site as the predevelopment condition.
Water quality treatment requirements are determined both by geography and by the land uses of proposed improvements. Geographically, the campus is located in a Basic Water Quality Treatment Area. All Campus District land uses are defined as Academic (BMC, 12.64.108 and 12.64.201(F)). Enhanced Basic Treatment is required if 50% or more of the runoff that drains to a water quality facility is from one or more of the following land uses: commercial, industrial, multi-family, or a road with 2,000 or greater average daily traffic (ADT).
Campus modeling was completed using WWHM-SWMM, which combines a continuous simulation hydrology model with a hydraulic model. Continuous simulation is the state-of-the art method for modeling a hydrologic cycle. It uses a long record of precipitation and an algorithm that is able to simulate the system impacts of back-to-back rainstorms and to simulate the duration, as well as volume, of flows and discharges. SWMM simulates hydraulic conditions in the conveyance system using flow rates and timing generated by WWHM.
Based on current requirements, flow control facilities are required for mitigation of stormwater runoff from development and redevelopment projects to the Conservation Flow Control Standard (Level 2). The Level 2 standard requires post-development flows to match the historic discharge durations for 50% of the 2-year peak flow through the 50-year peak flow and to match historic 2-year and 10-year peaks assuming a forested site as the predevelopment condition.
Water quality treatment requirements are determined both by geography and by the land uses of proposed improvements. Geographically, the campus is located in a Basic Water Quality Treatment Area. All Campus District land uses are defined as Academic (BMC, 12.64.108 and 12.64.201(F)). Enhanced Basic Treatment is required if 50% or more of the runoff that drains to a water quality facility is from one or more of the following land uses: commercial, industrial, multi-family, or a road with 2,000 or greater average daily traffic (ADT).
Campus modeling was completed using WWHM-SWMM, which combines a continuous simulation hydrology model with a hydraulic model. Continuous simulation is the state-of-the art method for modeling a hydrologic cycle. It uses a long record of precipitation and an algorithm that is able to simulate the system impacts of back-to-back rainstorms and to simulate the duration, as well as volume, of flows and discharges. SWMM simulates hydraulic conditions in the conveyance system using flow rates and timing generated by WWHM.
Percentile of local or regional rainfall events for which the institution manages runoff on-site using LID practices and green infrastructure:
95th
Optional Fields
Additional documentation to support the submission:
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Data source(s) and notes about the submission:
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