The lake probe is a measurement device designed to determine the low pressure gradients associated with the typical flow processes at the bottom of lakes and rivers. For example it is possible to establish whether water flows off via the bottom of the lake or river, or whether the groundwater additionally feeds the lake or river. This information is important for hydrological, hydrogeological and geotechnical monitoring amongst other things.
The measurement principle is based on the selective determination of pressure gradients between the pore water in the lake sediment and the absolute pressure from the free water level in a closed, water-filled system. In addition to the composition of the upper sedimentary layer (grain size, capillarity) and the consequent penetration resistance of the probe, the measurement process is above all influenced by hydraulically dynamic interactions between the current near the bottom of the water and the pore area current. The measurement equipment can be used up to a water depth of 40 m and operates at a fixed data recording rate of 20 s. The pore water pressure is determined using a differential pressure sensor, while the current water depth is calculated at the same time using an absolute pressure sensor. The measurement position of the probe at the bottom of the water can be checked using the integrated incline sensor.
Values are recorded and administered in a micro logger in a handheld format. The UGT software tools supplied with the equipment facilitate simple subsequent visualisation and processing of the data on the PC.
- Determination of the currently effective gradients at the bottom of the water
|Pore water pressure:|
-700 … 700 mmWS
|Water level absolute pressure:|
0 … 6000 cmWS
|Angle of incline:|
0 … 89°
|Art.-Nr.: 199000||Lake probe PD1|