Difference between revisions of "Category:Level 3 - Best management practices/Structural practices/Step pool"

Category:Level 3 - Best management practices/Structural practices/Step pool

[[File:Step pool.jpg|300px|thumb|alt=image of step pool|<font size=3>Stormwater step pool. Courtesy of Limnotech.</font size>]]

[[File:Step pool.jpg|300px|thumb|alt=image of step pool|<font size=3>Stormwater step pool. Courtesy of Limnotech.</font size>]]

Stormwater step pools are defined by design features that address higher energy flows due to more dramatic slopes than <span title="Dry swales, sometimes called grass swales, are similar to bioretention cells but are configured as shallow, linear channels. They typically have vegetative cover such as turf or native perennial grasses. Dry swales may be constructed as filtration or infiltration practices, depending on soils."> [https://stormwater.pca.state.mn.us/index.php?title=Dry_swale_(Grass_swale) '''dry swales''']</span> or <span title="Wet swales occur when the water table is located very close to the surface or water does not readily drain out of the swale. A wet swale acts as a very long and linear shallow biofiltration or linear wetland treatment system."> [https://stormwater.pca.state.mn.us/index.php?title=Wet_swale_(wetland_channel) '''wet swales''']</span>. Using a series of pools, riffle grade control, <span title="A species that has been observed in the form of a naturally occurring and self-sustaining population in historical times. Non-natives do not meet this definition."> '''native species'''</span> vegetation and a sand seepage filter bed, flow velocities are reduced, treated, and, where applicable, infiltrated. The physical characteristics of the stormwater step pools are similar to [https://cfpub.epa.gov/watertrain/moduleFrame.cfm?parent_object_id=1199 Rosgen A or B stream classification types], where “bedform occurs as a step/pool, cascading channel which often stores large amounts of sediment in the pools associated with debris dams” ([https://stormwater.pca.state.mn.us/index.php?title=References_for_high-gradient_stormwater_step-pool_swale Rosgen, 1996]). These structures feature surface/subsurface runoff storage seams and an energy dissipation design that is aimed at attenuating the flow to a desired level through energy and hydraulic power equivalency principles ([https://stormwater.pca.state.mn.us/index.php?title=References_for_high-gradient_stormwater_step-pool_swale Anne Arundel County, 2009]). Stormwater step pools are designed with a wide variety of [https://stormwater.pca.state.mn.us/index.php?title=Plants_for_swales native plant species] depending on the hydraulic conditions and expected post-flow soil moisture at any given point within the stormwater step pool.

Stormwater step pools are defined by design features that address higher energy flows due to more dramatic slopes than <span title="Dry swales, sometimes called grass swales, are similar to bioretention cells but are configured as shallow, linear channels. They typically have vegetative cover such as turf or native perennial grasses. Dry swales may be constructed as filtration or infiltration practices, depending on soils."> [https://stormwater.pca.state.mn.us/index.php?title=Dry_swale_(Grass_swale) '''dry swales''']</span> or <span title="Wet swales occur when the water table is located very close to the surface or water does not readily drain out of the swale. A wet swale acts as a very long and linear shallow biofiltration or linear wetland treatment system."> [https://stormwater.pca.state.mn.us/index.php?title=Wet_swale_(wetland_channel) '''wet swales''']</span>. Using a series of pools, riffle grade control, <span title="A species that has been observed in the form of a naturally occurring and self-sustaining population in historical times. Non-natives do not meet this definition."> '''native species'''</span> vegetation and a sand seepage filter bed, flow velocities are reduced, treated, and, where applicable, infiltrated. The physical characteristics of the stormwater step pools are similar to [https://cfpub.epa.gov/watertrain/moduleFrame.cfm?parent_object_id=1199 Rosgen A or B stream classification types], where “bedform occurs as a step/pool, cascading channel which often stores large amounts of sediment in the pools associated with debris dams” ([https://stormwater.pca.state.mn.us/index.php?title=References_for_high-gradient_stormwater_step-pool_swale Rosgen, 1996]). These structures feature surface/subsurface runoff storage seams and an energy dissipation design that is aimed at attenuating the flow to a desired level through energy and hydraulic power equivalency principles ([https://stormwater.pca.state.mn.us/index.php?title=References_for_high-gradient_stormwater_step-pool_swale Anne Arundel County, 2009]). Stormwater step pools are designed with a wide variety of [https://stormwater.pca.state.mn.us/index.php?title=Plants_for_swales native plant species] depending on the hydraulic conditions and expected post-flow soil moisture at any given point within the stormwater step pool.