Start Date: Sep 01, 2011
End Date: Sep 30, 2012
This collaborative project will involve scientists from USDA-ARS, Canaan Valley Institute, Virginia Tech, and West Virginia University. Research will be conducted at two watershed locations that represent the Appalachian Valley and Ridge region of the Chesapeake Bay basin. The first phase of research will involve the development of a reach-scale method for labeling stream bank sediments with rare earth elements and tracking their fate during successive storm events. This work will be carried out at Stroubles Creek, a 25 km2 mixed land-use watershed in Blacksburg, Virginia. Initial laboratory experiments will be conducted to understand rare earth element sorption to stream bank sediments and to determine the most appropriate method for labeling stream bank sediments with rare earth elements. A field study will then be conducted where stream bank sediments labeled with five different rare earth elements are artificially introduced into an experimental stream reach during selected storms. This study will enable mapping and characterization of stream bank sediment fate and transport in response to storm flows as well as test the ability of rare earth element tracers to quantify stream bank sediment contributions to suspended sediment loads in streams. The second phase of research will focus on evaluating sources of suspended sediment before and after stream restoration using the reach-scale sediment tracking methods developed and validated at Virginia Tech, as well as using established sediment fingerprinting techniques. This research will be conducted at select watershed locations in the Cacapon River watershed in West Virginia, where the combination of steep topography and anthropogenic disturbances, particularly those resulting from intensive agricultural and forest management activities, have led to problems with stream bank erosion and increased sediment yields. Three tributaries to the Cacapon River have been selected for study, each with steep, forested headwaters and mixtures of cropland and pasture land in the valley. Two of the tributaries will receive a battery of stream restoration practices to correct failing stream banks, whereas a third stream will not be restored and will serve as the control. Watershed-scale sediment fingerprinting techniques [inorganic elements, radionuclides, stable carbon (C) and nitrogen (N) isotopes, etc.] will be used to identify principal sources of suspended sediment before and after stream restoration on the treated watersheds as well as on the control. In addition, reach-scale studies using rare earth elements will be conducted on stream banks pre- and post restoration to evaluate the effectiveness of different practices. The project will yield a new methodology for tracking sources of sediment and will demonstrate a new application of sediment tracking technology for evaluating the effectiveness of stream restoration in mixed land-use watersheds of the Appalachian Highlands region of the Chesapeake Bay basin. In addition, results will help target stream restoration to maximize sediment reductions and improve water quality.