2012 Annual Report
A new follow-on agreement (Agreement #59-1930-1-171) was established in July 2011. This new agreement will replace the current agreement (Agreement #59-1930-6-649) when it expires on August 31, 2011. The new agreement runs from September 1, 2011 through September 30, 2012. The funds will be used to develop novel sediment source tracking methods and to test their ability to quantify sediment source reductions following stream restoration. In July 2010, a reach-scale sediment source tracking study was initiated at Stroubles Creek in Blacksburg, VA. The overall goal of the study is to determine whether stream bank sediments labeled with rare earth elements can be effectively tracked in stream water during storm events. This study serves as the thesis project for a Master’s student at Virginia Tech. The principal investigators on the project met with the Master’s student on August 19-20, 2011 to lay out specific study objectives and outline experimental procedures. Regular conference calls have been held since then to discuss results and to evaluate progress. In September and October 2010, a set of 25 soil samples was collected from sites in Stroubles Creek and three small tributaries to the Cacapon River. All soils were analyzed for a suite of 21 potential sediment tracers including inorganic metals, two rare earth elements, and Cs-137. The goal of this initial sampling was to establish background concentrations of potential sediment tracers in soil, and to determine whether Cs-137 could be used to distinguish upland soils from stream bank sediments. Preliminary results suggest that Cs-137 could be a useful tracer in Stroubles Creek and in one of the tributaries to the Cacapon River. A more thorough soil sampling program will be conducted in Stroubles Creek and select sites in the Cacapon River during the fall of 2011.
A suspended sediment monitoring program was begun on Stroubles Creek during the fall of 2010. A similar program will be initiated on the Cacapon River sampling sites this fall. Simple passive samplers are being used to collect suspended sediment during storm events, which will then be analyzed for sediment tracers. The results of this effort will be combined with data from the soil characterization work described above to ascertain the relative importance of upland versus stream bank sediment sources at each watershed monitoring location.