TESTING THE EFFECTIVENESS OF EMERGING TECHNOLOGIES FOR DEVELOPING A SEDIMENTATION MODEL AT CLAYTOR LAKE, DUBLIN, VIRGINIA - A PROGRESS REPORT

Unmanned aerial vehicles (UAVs), side-scan sonar (SS), and submersible remotely operated vehicles (ROVs), are being tested for their effectiveness in characterizing the nature and rates of adverse siltation in the upper reaches of Claytor Lake, near Radford, Virginia.

Claytor Lake covers 4,500 acres and formed as a result of construction for a hydroelectric dam on the New River in the 1930’s. Pulaski County relies on water drawn from the lake to supply communities near Dublin, Virginia. In recent years, the upper reaches of the lake have been experiencing detrimental sedimentation, especially on the insides of partially submerged meander bends. In addition to other impacts, siltation has negatively affected water intake structures, requiring periodic dredging to keep them operational.

UAVs from Radford University's Geohazards Research Center have been flown, over selected areas, to map changing shorelines, as well as both erosional and depositional features, using sensors that incorporate a range of visible and near infrared spectra. Areas sensitive to sedimentation include docks, navigable channels, recreation sites, and water supply intake pipes. Experimental aerial assessments of silt turbidity and water visibility are being compared to data collected by more traditional methods, such as using Secchi disks. Correlations between the different methods have been made.

Side-scan sonar has been utilized to generate bathymetric maps and digital 3D models of the lakebed in these areas of the lake. Those maps and models provide a baseline for later comparisons to assist in evaluations of rates and volumes of sedimentation. Finally, after suitable targets have been identified using UAVs and sonar, the Radford University ROV submersible was deployed to provide video imagery of features of interest at those targets. This study is being done with the goal of creating sedimentation models for key places in the lake; and, to evaluate the use of near infrared imagery for sedimentation mapping.