Herrera has extensive expertise in surface water hydrology and engineering to support a wide range of water resource projects including river reach analyses, regional watershed master planning, design of stormwater flow control and treatment facilities, stormwater planning and design for low impact development projects, wetland studies, flood frequency analyses, and flood risk assessments.
We use continuous simulation hydrologic modeling techniques for small- and large-scale catchments including HSPF, XP-SWMM, Infoworks CS, MGS Flood, WWHM3, KCRTS, and HEC-HMS. We also use single-event modeling techniques as applicable, depending on local regulatory requirements. Single event models regularly used include StormShed, SBUH, and XP-SWMM (event mode).
Key Projects
- Cispus River Reach Analysis – Lewis County Department of Public Works
- Bogachiel River Reach Analysis – Washington State Department of Transportation Environmental Affairs Office
- Manitou Beach Salt Marsh Restoration Feasibility Analysis – City of Bainbridge Island
- SR 518 Widening – Washington State Department of Transportation
- Southeast Issaquah Bypass Environmental Impact Statement – City of Issaquah Public Works Department
- Low Impact Development Technical Guidance Manual by Puget Sound Action Team, WA – Contributing author
- Lakewood RainCatchers – Pilot project to test cost-effectiveness of rain gardens, vegetated swales, and drainage cisterns; Seattle Public Utilities Engineering
- High Point Revitalization – Low impact development design support and modeling for urban subdivision/mixed use development; City of Seattle, Seattle Public Utilities
- Rainwise Stormwater Incentives Package to encourage onsite low impact development features – Seattle Public Utilities