Reservoir Safe Yield Analysis

Pedlar Reservoir Investigation

Lynchburg, VA

Owner: The City of Lynchburg, VA

Safe yield is defined as the amount of water that a drainage basin/reservoir can provide during both wet and dry periods. Estimating both existing and future safe yield is a major concern with all State and/or municipal authorities charged with managing water supply systems. Two measurable and predictable variables affecting a system's safe yield are population growth and loss of reservoir capacity due to siltation.

To support a reservoir siltation analysis of the Pedlar Reservoir, Ocean Surveys performed a detailed hydrographic survey and calculated the existing capacity. Following completion of the survey, a Digital Terrain Model (DTM) of the reservoir bottom surface was created and used to compute storage volumes at one-foot drawdown intervals. The elevation data were also used to determine the volume of siltation accumulated since the previous survey.

Figure 1: The Pedlar Reservoir Dam.

Figure 2: Presentation of Pedlar Reservoir hydrography defined by a 5-foot contour interval.