| Targeting Riparian Management to Enhance In-Stream Nitrogen Removal | 0208534 | Gold, A. J. | 10/01/2006 | 09/30/2009 | COMPLETE | KINGSTON | nitrogen, nitrate, streams, riparian zones, denitrification, woody debris | Watershed processes can reduce the export of nitrogen to surface waters. Because streams vary markedly in their capacity for nitrate removal, in-stream nitrate processing is an emerging research area with extensive unanswered questions. The purpose of this study is to improve our capacity to target site-specific nitrate control strategies to locales with high potential for export to coastal waters. | The goal of our research is to characterize the extent of in-stream nitrate removal in low gradient streams and identify stream attributes that relate to elevated nitrate removal rates. As we gain more insight into in-stream nitrate removal, we will be able to contribute to the scientific dialog that seeks to target site-specific nitrate control strategies to locales with high potential for export to coastal waters. Forested riparian zones are a source of woody debris and leaf litter that can promote the growth of biofilms and anaerobic microsites where in-stream denitrification can occur. Outputs, Outcomes and Impacts: We expect that the long term outcome of this work will be improvements in the water quality and fisheries of estuarine systems resulting from decreased watershed N loading. At the intermediate time scale, outcomes from our work will contribute to efficient watershed management, by fostering improvements in the selection of locales for individual and
public investment of pollution control and restoration, a key goal of the Clean Water Act Total Maximum Daily Loads (TMDLs) program and the recent Conservation Effects Assessment Program (CEAP) of USDA. In addition, our work will help guide stream/riparian restoration and management practices via Federal and state programs (e.g., NRCS EQIP; RI DEM, Narragansett Bay Restoration efforts). Our work will contribute directly to stream restoration research and Extension efforts promoted by New England Land Grant Universities through the CSREES New England Regional Water Quality Program (A. Gold, PI) and the CSREES National Integrated Water Quality Program. Objectives and Hypotheses: We hypothesize that substantial in-stream denitrification will be observed in low gradient streams bordered by forested riparian zones. In this project we will begin to test our hypothesis by exploring relationships between hydrologic residence time, woody debris, and in-stream denitrification. With this study
we will advance our ability to identify ecosystem factors that control the N sink function of streams in coastal watersheds. Objectives: 1. What are the characteristic reach properties of 4-5 streams that encompass a range of forested riparian cover? What are the morphometric channel properties, seasonal discharge and hydrologic parameters, sediment characteristics, evidence of disturbance, woody debris volume, and stream chemistry of these streams? 2. What is the extent of in-stream denitrification [determined via in-stream, reach-scale tracer denitrification studies] in the characterized low gradient streams? What is the relationship between in-stream denitrification and hydrologic residence time and woody debris volume? |