Determination of the spatiotemporal potential for developing an ecological groundwater withdrawal management plan

摘要

To protect groundwater-dependent ecosystems against degradation, an ecologically sustainable management plan for groundwater resources is required by law. In the current licensing practice, groundwater withdrawals are assessed separately with regard to their environmental impacts, even if the operating modes of many different waterworks of large water suppliers have a hydraulic effect on each other. To develop a concept for developing an ecological withdrawal management plan for the waterworks of the city of Karlsruhe, several steps were carried out: (1) Development of a transient numerical finite element groundwater model, which includes all waterworks with their hydraulically connected catchment areas, (2) Identification of minimum water withdrawal rates, which are acceptable legally, technically and with respect to water quality, and which can be realized in practice, and (3) Determination of the spatiotemporal operating potential by means of simulation studies. This operating potential has been described for each waterworks in scale and range, so that the effective area of an ecological withdrawal management plan can be identified. As the water deficit resulting from withdrawal reductions in a waterworks needs to be distributed to other waterworks, environmental improvements in one location may be accompanied by environmental degradation elsewhere.