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Reservoir Bathymetric Surveys
Capacity, Contour & Siltation Assessments


Reservoir Bathymetric Surveys have traditionally been considered difficult, time consuming and expensive. Because of this, most large reservoirs overseas and in the UK have not been surveyed or checked since their construction.

Consequently, the capacity of these reservoirs (and the associated active supply) is

often based on "as designed" drawings and may be well out of date and inaccurate due to silt, vegetation and debris accumulation, or even errors in the original survey.

Based on extensive practical experience in remote locations overseas, where transport and data collection are frequently difficult, we have developed portable, reliable and accurate methods for rapid and cost-effective determination of reservoir capacity, contouring and siltation checks.

Survey Techniques

We use highly accurate NMEA digital output acoustic based sonar, giving a proven resolution of ± 0.1m to 100m depth, coupled to a GPS receiver to give the positional location,

which will typically be ± 3m accuracy. This is more than sufficient to accurately determine eventual reservoir capacity. Use of software packages such as GISmo™; allows us to preload geo-referenced aerial photography or other maps onto GPS linked PDA devices for on-site checks and "instant mapping"

Provided the survey is carried out at Full Supply Level or greater, the water surface provides easy access to any point of the reservoir, so the survey is usually more detailed and extensive than the earlier ground survey.

The sonar is towed by a lightweight boat, but can even be tied to a canoe where access is difficult. Numerous point depths are surveyed (typically at least one per 50 m²), more in complex areas such as inlets. These survey points are transferred to a 3D terrain model within a Geographic Information System for processing.

The Outputs

The primary outputs are bathymetric contour

and 3D contour plots at any desired interval, typically 1m, presented as a hard copy or digital overlay onto .dxf drawings or aerial imagery background.

The contours are used to determine an accurate "level area volume" relationship for the reservoir which is essential for reliable yield calculations, release scheduling or evaporation estimates.

The Benefits

  • Fast
  • Accurate
  • Reliable
  • Cost-effective
  • Informative

The reservoir is mapped in ultra high resolution, all processed information made available in a range of digital formats.

Reservoir volume is checked and updated, silt deposition patterns can be mapped and contours and cross-sections determined, useful for targeted water quality sampling.

For further information or a quotation, please email or phone +44 (0) 1392 666 953

Specialist cost-effective reservoir and estuary surveys Depth and bathymetry surveys
Contour plotting & 3D modelling
Siltation checks
Reliable yield assessment