Groundwater level plan
A groundwater level plan shows the flow conditions of the groundwater for a limited section of the near-surface subsurface , usually on a certain reference date . It is based on the groundwater levels that were measured in the corresponding area in a certain aquifer at certain points on the reference date. The lines of the same groundwater level in the aquifer resulting from the interpolation of the punctual measurement data are referred to as groundwater levels . The presentation, like a card customary two-dimensionally in supervision , by projecting the groundwater contours in the map layer. Groundwater level plans are drawn up individually for each aquifer.
For the construction of a groundwater level plan, at least three groundwater measuring points are required, each of which must be at least 20 meters apart and the upper edge of which has been measured for a uniform reference height (e.g. the height above sea level ). The distance to the groundwater ( tapping , relative value ) determined in such a measuring point on the reference date by means of a light plumb line is converted into the absolute value by subtracting the height of the upper level .
Between the different groundwater measuring points, based on the absolute values, the groundwater equivalents e.g. B. be interpolated with the help of hydrological triangles . The groundwater flow direction can be determined from the course of the groundwater levels: It always runs across the groundwater levels from high to low absolute values.
literature
- Maria-Theresia Schafmeister: Geostatistics for hydrogeological practice . Springer Science + Business Media , 1999, ISBN 978-3-642-58567-8 ( Google Books ).