Tuesday, November 6, 2007
204-17

Nutrient Transport through Vegetated Filter Strips in the Mid-Atlantic Coastal Plain Region.

Jennifer Gilbert, University of Delaware, Department of Plant and Soil Sciences, 152 Townsend hall, Newark, DE 19716-2170 and James Thomas Sims, 531 S. College Avenue, University of Delaware, University of Delaware, Department of Plant & Soil Sciences, Newark, DE 19717-1303.

Eutrophication of surface waters due to nitrogen (N) and phosphorus (P) pollution is a key concern in the state of Delaware.  To limit the transport of nutrients and prevent further nutrient enrichment of water resources, vegetated filter strips (VFS) have been suggested as one best management practice (BMP) option.  The use of VFS as a BMP has been shown to decrease nutrient transport to surface waters mainly through sedimentation and infiltration of storm water runoff.  The majority of the state of Delaware falls within the Coastal Plain physiographic region.  Here, soils are sandy with low phosphorus sorption capacity and the water table is seasonably at or near the soil surface.  It is in this landscape that a field study was conducted to determine how N and P are transported from agricultural fields, through VFS to adjacent water bodies, in this case a tax ditch.  Due to results from previous research highlighting the importance of stormwater infiltration as a mechanism for decreasing nutrient transport, particular focus was placed on subsurface transport in shallow groundwater.  Water samples were collected from September 2006 – 2007.  Stormwater runoff was collected within 24 hours of a storm event.  Groundwater and tax ditch (when flowing) water samples were collected weekly as well as within 24 hours of a storm event.  All water collected was analyzed for total and dissolved phosphorus, nitrate and ammonia.  Runoff samples were also analyzed for total suspended solids.  Results will be presented to show how VFS function in the Coastal Plain landscape, and specifically to determine if nutrients in infiltrated stormwater runoff can be considered attenuated by the VFS.