Hydrological triangle
The hydrological triangle is a method for creating a groundwater level plan . This method can also be used to quickly determine the direction of groundwater flow.
requirements
To use this method, a key date measurement of the height of the groundwater surface above sea level must be carried out at at least three observation gauges or wells . In addition, the location of all measuring points must be known. It must be ensured that all gauges are sunk into the same aquifer in order to avoid misinterpretations of the measured values. Furthermore, the aquifer should be largely homogeneous in its permeability and largely the same in its thickness in the measurement area . There should also be a low hydraulic gradient of <1% and thus an almost horizontal flow.
Procedure implementation
In order to create the groundwater level plans, three of the measuring points are connected to form a triangle. Then the height differences of the measured groundwater level are distributed linearly over the distances of two gauges and interpolated on the respective side of the triangle. So at a distance of z. B. 100 m and a height difference of the groundwater level of 1 m, every 10 m distance 0.1 m can be added to the level of the level with the lower groundwater level. After creating the triangle with the points of the same height, the points of the same height are connected. The resulting parallel straight lines represent groundwater level. The groundwater flow direction runs perpendicular to this groundwater level from the highest to the lowest groundwater level.
Several measuring points are necessary to develop a typical groundwater level plan with curved groundwater levels. It is possible to interpolate curves over the constructed points at the same height and thus develop a groundwater level plan.
literature
- Georg Matthess, Károly Ubell: Textbook of Hydrology Volume 1 General Hydrology - Groundwater Balance . 2nd Edition. Borntraeger brothers. Berlin, Stuttgart 2003, ISBN 3-443-01049-0 .
- Ekkehard Heinemann, Rainer Feldhaus: Hydraulics for civil engineers . 2nd Edition. BG Teubner Verlag / GWV Fachverlage GmbH. Wiesbaden 2003, ISBN 3-519-15082-4 .