Multi-benefit Modeling for Basin Planning


Projects > Stormwater Management > Implementation Planning

Watershed-scale Optimization to Improve Hydrology and Achieve Goals Related to Aquatic Health and Water Quality

End Client:  Snohomish County (in partnership with Northwest Hydraulic Consultants)

Paradigm, as part of the Northwest Hydraulic Consultants team, supported Snohomish County, WA in developing a comprehensive basin plan for stormwater management in the Little Bear Creek watershed. The plan identified feasible management strategies for addressing multiple benefits, including hydrograph restoration for benthic health (peak, volume, duration control), sediment, bacteria, metals, and temperature. Utilizing a “Future Development” scenario modeled using Hydrological Simulation Program--Fortran (HSPF), Paradigm led the development of a multi-tiered watershed-scale optimization modeling approach using the System for Urban Stormwater Treatment and Analysis IntegratioN (SUSTAIN).

The optimized results from the coupled SUSTAIN-HSPF continuous-simulation models were protective of hydrology and water quality over a 60-year range of meteorological conditions. Paradigm also developed an interactive web-based viewer for presenting SUSTAIN optimization results to a diverse group of stakeholders. The viewer uses the latest HTML5 standards for cross-platform compatibility on desktop and mobile devices. OpenLayers was used for mapping and D3.js for web-based charting. The information in the Viewer highlights the basin plan solutions and BMP capacities along with a summary table of BMP capacity, performance, and associated lifecycle costs.