Reservoir volumetric and sedimentation survey data: A necessary tool for evaluating historic sediment flux and appropriate mitigation response uri icon

abstract

  • AbstractMultifrequency reservoir survey techniques offer a technological means to verify historic sediment delivery estimates and to quantify the effectiveness of conservation implementation. A multiyear, multifrequency acoustic survey of Granger Lake, Texas, was undertaken to demonstrate the application of this technology and the value of its derivatives. Granger Lake is a drinking water resource for surrounding cities, perceived as being threatened by agriculturedriven sedimentation, and the focus of a watershed conservation implementation programme. Objectives of the present study were to (i) conduct subbottom profiling to verify the preimpoundment capacity of the reservoir; (ii) plot historic bathymetric datasets, including preimpoundment surface determined by lowfrequency acoustics, identifying any changes in annualized sediment delivery curve to date; and (iii) quantify changes in sediment delivery resulting from agricultural conservation practices implemented as part of the Granger Lake Watershed Assessment and Implementation Project. The sedimentprofiling results indicated that the preimpoundment design estimates were overstated, thereby skewing historic sediment delivery estimates. Adjusting the 1980 preimpoundment volume of Granger Lake indicated that the historic trend in Granger Lake sedimentation/water storage loss was markedly less acute. Although sedimentation did accelerate somewhat in the mid1990s, the intervals following the 19952002 survey period revealed a trend of decelerating sedimentation. Reduced sedimentation as a response to conservation implementation is not distinguishable beyond what is seen as a steady downward trend in sediment delivery. Insights from this study highlight the important role of multifrequency reservoir survey techniques for refining watershed conservation and/or reservoir sustaining strategies.

published proceedings

  • Lakes & Reservoirs Science Policy and Management for Sustainable Use

author list (cited authors)

  • McAlister, J. R., Fox, W. E., Wilcox, B., & Srinivasan, R.

complete list of authors

  • McAlister, Jason R||Fox, William E||Wilcox, Bradford||Srinivasan, Raghavan

publisher