Author(s): Ryan J. Winston; William F. Hunt
Linked Author(s):
Keywords: Level spreader; Vegetative filter strip; BMPs; Best management practices; Stormwater; Urban; LID; Low impact development; SUDS
Abstract: Traditional construction practices lead to degradation of watershed hydrology through increased flow in pipe networks, increased flow volumes, decreased groundwater recharge, and increased peak flow rates. Recent regulations in North Carolina have led to the use of level spreaders in combination with vegetative filter strips as an end-of-pipe method to reduce erosion and decrease stresses on riparian buffers. However, little research has been done to evaluate their effectiveness. A total of four level spreaders were studied at two sites, Apex and Louisburg, NC. At each site, stormwater from small, impervious watersheds (0.4 ha or less) was conveyed to two level spreaders. Flow was released along the length of the level spreaders and into two vegetative filter strips. This study evaluated the hydrologic and water quality benefits of level spreader–vegetative filter strip systems. Differing buffer widths and vegetation types were examined. Hydrologic results show that flow volumes were reduced by 50%or more, and peak flow rates were reduced by 70%or more. The systems reduced TSS and sediment bound nitrogen and phosphorus forms. Load reduction was observed for all pollutants studied. A level spreader–vegetative filter strip can function as an effective LID/SUDS practice.
Year: 2010