Reservoir Surveys

Navajo Canyon TIN generated from multibeam data.

The Sedimentation Group has monitored reservoir sediment since the closure of the first Reclamation dam structures in the early 1900’s. Reservoir surveys are conducted for the purpose of updating the area-capacity relationship and computing annual sediment inflow to project useful operation of existing facilities. Reclamation has over 400 storage facilities, but only around thirty percent have had resurveys conducted since initial filling. Of those resurveys, about thirty percent have had multiple surveys since they are located in high sediment inflow zones. The majority of the high sediment inflow sites are located in the southwestern United States and include Theodore Roosevelt Reservoir in Arizona with eight resurveys, Elephant Butte Reservoir in New Mexico with twelve resurveys, and Lake Mead in Arizona with three resurveys. There are also reservoirs in the state of Wyoming with high sediment yields that have had several surveys, such as Yellowtail Reservoir with two resurveys, Buffalo Bill Reservoir with three resurveys, and Guernsey Reservoir with eleven resurveys.

Monitoring methods have varied over the years and range between reconnaissance level and detailed field collection and analysis. Survey equipment has transformed dramatically throughout Reclamation’s history with the greatest changes occurring over the last decade. The latest major change in horizontal positioning is the use of global positioning systems (GPS) that is more accurate and less costly to operate than past survey methods. No former positioning system has been so rapidly adapted for hydrographic data collection. The most recent significant development in depth sounding is the multibeam system which makes the efficient collection of massive amounts of topographical data possible. The multibeam system provides the option of complete coverage of the underwater areas, thus removing the unknowns of previously unmapped underwater areas. The Sedimentation Group adopts available survey collection and analysis techniques only if they help streamline the collection and analysis process while providing additional information for Reclamation studies.

Multibeam Generated Image of Hoover Dam and Intake Towers

The following images were created from processed multibeam data collected during the Sedimentation Group’s 2001 survey of Lake Mead. The first image was generated from multibeam data of Hoover Dam and intake towers. The second image shows multibeam data from a single pass over a B29 that crashed in the reservoir nearly 60 years ago.

Report Downloads

Reconnaissance Technique for Reservoir Surveys (2006), pdf 4.7MB

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Computing Degradation and Local Scour: Technical Guidelines for Bureau of Reclamation (1984), pdf 8.0MB

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Reservoir Sedimentation: Technical Guidelines for Bureau of Reclamation (1982), pdf 5.9MB

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Following are reservoir survey reports that have been completed over the years by the Sedimentation Group. The reports contain the results and methodology used to measure the reservoir topography and sediment deposition.