Bathymetric survey is the process of depth data acquisition (bathymetry) in the survey coverage area.
For this purpose, special equipment is used, though it can be performed manually in specific situations.
Depth soundings can be classified according to the measurement techniques as follows:
- depth echo sounding;
- depth sounding by pole or a hand-lead sounding;
- mechanical sounding (using a hydrometric sinker on a winch with a counter).
In our case, sounding operations are performed by an echo sounder with depths digital recording on an electronic data storage device and by a self-recorder that continuously records the bathygram along the tack in Real Time Kinematic (RTK) with reference to a GPS Base Station.
Figure 1 – Sounding operations
Processed results of the bathymetric survey represent a georeferenced dataset containing information on the spatial distribution of depths in the survey coverage area. Depending on the preferred coordinate system, each depth is represented as a combination of 3 values: BLZ (Geographic latitude; geographic longitude; depth), or XYZ (Rectangular latitude and longitude depending on the projection preferred; depth). Bathymetric data (bathymetry) with time can be used for general analysis of the bottom topography and mapping or addressing the applied problems (sediment accumulation analysis, dredging monitoring, etc.).
Figure 2 – Bathymetric data
The lake bottom topography provides additional insights into sediment and nutrient loading, and water resources management. This information is used not only in numerical simulation of water circulation and hydrodynamics, but also has an impact on the chemical composition of water and the distribution of aquatic animals and plants populations. The lake bottom topography has been widely used over recent years to study changes in the flooding and lakes levels and to monitor natural disasters caused by floods. The bottom topography of a lake or river can be significantly changed by various natural and anthropogenic processes.
Figure 3 – Bathymetric map
A set of topographic, geodetic and aerial surveys provide reports and reported data, which are used later to assess the hydrographic characteristics of water bodies.
Orthophotomaps and bathymeriс measurements are used to create three-dimensional models of water bodies that allow accurate calculations to determine the water-surface area and the water volume.
Figure 4 – Three-dimensional model of lake