At a Glance
A regenerative stormwater conveyance approach improves stormwater treatment, while rehydrating riparian wetlands, re-establishing ecological processes, and improving stream aesthetics and natural resource function.
Project Description
Biohabitats, Inc., has designed an innovative regenerative stormwater conveyance (RSC) system on approximately 1,000 linear feet of an actively degrading tributary to the Chesapeake Bay located in the coastal plains of Anne Arundel County. The stream was intermittent and downcut approximately 12 feet deep, originating at a roadway culvert.
Using RSC, the incised channel was filled with porous, granular material held in place with grade control weirs and cobble riffles. An energy dissipation pool at the upstream end of the project provides some energy reduction and infiltration of the stormwater before it flows into the channel. As the flow ramps up and fills the initial pool, seepage through the granular channel fill begins its sub-surface movement down the channel bed. With increasing flow, each pool fills with water before flowing over the cobble riffle/boulder grade control downstream to the next pool. Each pool also loses water through its bottom into the granular channel fill, which reduces in-channel flow and recharges the local shallow ground water table. Once the channel storage volume is saturated, water flows through the channel downstream with much less velocity, volume, and erosion potential. At higher discharges, the weirs force a broad, shallow, non-erosive flow that reduces sediment load and incision while transitioning the intermittent nature of the channel back towards its perennial origin.