2012 Annual Report
1a.Objectives (from AD-416):
Develop and validate methods to identify critical source areas of soil and nutrient loss in agricultural catchments of the Chesapeake Bay drainage basin using remote sensing techniques, particularly LiDAR-developed topographic maps.
A. Develop technology for detection of runoff and erosion prone critical source areas in steeply sloped landscapes of the Chesapeake Bay drainage area.
B. Develop technology for detection of runoff and nutrient loss critical source areas in nearly-level landscapes of the Chesapeake Bay drainage area.
1b.Approach (from AD-416):
This collaborative research will involve USDA-ARS and Canaan Valley Institute (CVI) scientists, in the context of ongoing research initiatives, particularly the Conservation Effects Assessment Project. Research will be conducted at sties representative of landscapes and agricultural practices within the Chesapeake Bay drainage basin, including the Mid-Atlantic Highlands of Appalachia, Allegheny Plateau, Valley and Ridge, and Atlantic Coastal Plain. Research in steeply sloping landscapes will center on identification of areas of high frequency runoff generation and erosion and on improving site assessment index application using high resolution elevation models. Research in nearly level landscapes will focus on characterization of overland flow and subsurface recharge areas, drainage ditch networks and critical control points favorable to different management practices. Testing of remote sensing applications will take advantage of ongoing USDA-ARS watershed studies (Choptank, Manokin, Mahantango, Town Brook) to assess the potential to remotely identify critical source areas of nutrient loss. Research in the Choptank watershed will involve direct collaboration with scientists at the Hydrology and Remote Sensing Laboratory in Beltsville, MD. Existing soil and water quality monitoring data from these established experimental watersheds, as well as direct sampling and new experimentation, will be used to support testing. CVI scientist will acquire and process remotely sensed data (e.g., LiDAR and hyperspectral). With these data, USDA-ARS and CVI will collaboratively develop of novel inference techniques to identify areas of flow favorable to nutrient transport. Critical flow areas will be used to target areas where investment in additional conservation practices can be expected to achieve maximum water quality benefit and to evaluate the effectiveness of existing conservation practices. USDA-ARS and CVI will evaluate the potential for widespread application of newly identified inference techniques and participate in the development of strategies for their use in watershed management.
This project (Agreement #59-1930-6-649) expired on August 31, 2011. It was replaced by a new follow-on agreement (Agreement #59-1930-1-171), which began on September 1, 2011. This is the final report to document research conducted under an Assistance Type Cooperative Agreement between Canaan Valley Institute (CVI) and ARS.
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.