Stormwater requirements stack up quickly: water quality treatment, flow control, detention volume, and the analysis that proves all of it to a reviewer. We can design the full system, but on every project we look for the simplest, least costly layout that still satisfies the jurisdiction. We work with agencies across Oregon and Washington and design to DEQ, Ecology, and local stormwater management requirements.
What We Deliver
- Hydrologic and hydraulic modeling. Continuous simulation in WWHM, backed by spreadsheet calculations for sizing, so every facility dimension traces back to documented inputs.
- Water quality treatment. Selection and layout of treatment options such as biofiltration units (Filterra, for example), modular wetland systems, and filter cartridge units.
- Detention. Storage in vaults, ponds, oversized pipe, or arched pipe, chosen to fit the site and the budget.
- Flow control structures. Orifice and weir control structures, sized by iterating the model until release rates pass.
- Flow duration analysis. Showing that the developed site meets duration-based storm standards where the jurisdiction requires them.
- Erosion and sediment control plans and stormwater reports to accompany permit and land use submittals.
Typical Projects
- Plans and stormwater reports supporting a boundary line adjustment and development review application for a multifamily development in Tacoma, Washington.
- An office addition in Washington County, Oregon, with new parking, water quality treatment, and flow control, including service provider letters from Clean Water Services and the local water district.
- Paving and erosion control plans for a low impact design road project submitted to the City of Portland.
Standards We Work To
Oregon DEQ and Washington Department of Ecology requirements, together with the local stormwater manual that governs the site, such as Clean Water Services standards in Washington County.