Water Resources Research Act Program

Details for Project ID 2013NJ341B

Assessing the role of wetland flora as a sink for nutrients in subsurface gravel wetlands in New Jersey

Institute: New Jersey
Year Established: 2013 Start Date: 2013-03-01 End Date: 2014-02-28
Total Federal Funds: $5,000 Total Non-Federal Funds: $10,000

Principal Investigators: Kyle Seiverd, Louise Wootton

Abstract: Nutrient pollution from stormwater flows is a serious problem for many aquatic ecosystems, including Barnegat Bay. The University of New Hampshire’s Stormwater Center (UNHSC) developed a subsurface gravel wetland (SSGW) designed to remove nutrients from runoff, and several modifications of this design have subsequently been proposed. To test their relative effectiveness in nutrient removal, four gravel wetlands are being constructed at Georgian Court University: a standard “UNHSC SSGW”, two modified UNHSC SSGWs, one using simplified plumbing and the other using a deeper gravel layer to increase water storage capacity and fourth an Advanced Bioretention System (ABS) which delivers runoff vertically and uses different substrate. Nitrogen removal in these wetlands happens via two pathways: microbial denitrification and sequestration into plant biomass, while phosphorus removal is largely a result of physical retention on particles as well as sequestration into plant biomass. So far, studies assessing nutrient removal have focused on the microbial and physical removal processes. Little is known about the role of the vegetation in nutrient reduction within these systems. The goal of this study, then, is to compare the amounts of nutrients sequestered by the dominant plant species within these wetlands and to determine the optimal harvest period of plant biomass to maximize nutrient removal. Quadrat counts and clip plots will be used to monitor biomass and plant tissue analysis will be used to assess nutrient sequestration. The resulting data will be used to develop best management practices for stormwater basin plantings and vegetation management.