Groundwater Levels and Catchment Areas for Waterworks 1990
Catchment Areas for Waterworks: Methodology
The groundwater catchment area for Berlin waterworks are given directly by groundwater contours; the borders of the groundwater catchment areas run perpendicular to the watertable isohypse lines.
The previously described deficiencies in the groundwater contour maps used are reflected in some areas in the Map of Catchment Areas too. These deficiencies were somewhat balanced out by including original values; taking the waterworks in Brandenburg into consideration; and by the approximate calculation of the areal extent of individual groundwater catchment areas required for those amounts of groundwater withdrawals. The estimated groundwater recharge amounts of the catchment areas (method after Schlinker, KdT 1980) were compared with the groundwater improvement programs of waterworks, taking into consideration the proportions of bank-filtered water and groundwater recharge. The Gatow/Tiefwerder area was also supplemented by the contents of a hydrogeological expert analysis of the Berlin Public Water Companies (Leibenath 1990).
A main problem in the delineation of catchment areas was the uncertain connection of surface water to groundwater; it may be mostly sealed off by sewer systems and thick waste sludge layers. It must also be considered that the map only portrays conditions in the first groundwater level. Well galleries which withdraw from other levels have different, sometimes much larger catchment areas whose borders are not yet known.