Bathymetry: essential for up-to-the-minute sediment management
Bathymetry is a technology that provides a precise record of the evolution of silting in reservoirs. Sediment management is gaining in efficiency.
After several decades of operation, the accumulation of sedimentary deposits in our alpine reservoirs can impact the functionality of the structures concerned. This calls for reviews, plus anticipated and predictive management of the alluviation of these basins to ensure their storage capacity as well as the proper functioning of their production facilities.
In this context, bathymetry – especially since the advent of multibeam technology – is proving to be the best non-invasive method of mapping reservoir bottoms, since it provides precise data on the state of silting in a body of water. While a one-off reading is no more than a snapshot of the current state of the alluvium, the real added value of these measurements lies in their repetition. The ability to analyse and compare successive states provides highly usable information in respect of sediment management.
This includes the volume of sediment deposited during the period between two surveys and the annual rate of alluviation. The distribution of these deposits in the reservoir is precisely determined, providing reliable indications of the sedimentary process.
Optimising reservoir maintenance
This data facilitates predictive management of reservoir sedimentation. Emptying and sediment extraction operations and deposit minimisation measures are thus optimised, since the volumes of sediment and rate of alluviation are precisely quantified. Moreover, the 3D model resulting from these bathymetric measurements is also key to the use of the automated extraction robots now appearing on the market.
To give one specific example, it has been possible to halve the frequency of emptying at one facility, thereby reducing, also by half, the costs and risks associated with operations of this nature. Similarly, at another strategically important facility, a major project to remove sand has been initiated on the basis of comparative analyses carried out using this technology.
Sediment management has become reliant on accurate, reliable and repeatable bathymetric data, which is now a sine qua non in this sector of activity.
Bathymetry uses this type of multibeam echosounder for underwater measurements
Bathymetry provides a terrain model like this
This model shows the distribution and quantity of sediment deposits in the structure. Red and green are deposits; blue represents erosion.
