![[Translate to English:] The figure shows a map to select a polygon, for example a drinking water protection area. A bar chart illustrates what can be compared in the demonstrator tool. The quantities shown are merely examples. The chart shows similar amounts of direct and indirect groundwater recharge. In the stress year, both values are notably lower, particularly direct groundwater recharge. Water demand for agriculture and drinking water is similar in each case. It is lower than groundwater recharge but exceeds the sustainability threshold of 30% of groundwater recharge.](https://innovationsatlas-wasser.de/fileadmin/_processed_/a/3/csm_2026-08-06T07_17_59_00_00-Titelbild_5d9c014b8c.jpg "[Translate to English:] Map search of the WaStRes application and graphical example: Comparison of direct and indirect groundwater recharge based on long-term averages and in a selected stress year (e.g., a known dry year) with the potential water demand for agriculture and drinking water. @WWL Umwelttechnik und Uni Freiburg")
The Web GIS demonstrator allows users to interactively compare direct and indirect groundwater recharge with water demand, such as for drinking water or agriculture. Combined with an assessment of water quality, this provides a framework for evaluating resilience as the basis for the sustainable management of groundwater resources.
The central element of the demonstrator is the comparison of groundwater recharge rates (water availability) with known or estimated withdrawals for drinking water supply, as well as with the potential maximum irrigation demand in agriculture (water demand). Both direct and indirect groundwater recharge were quantified using a model-based approach in the StressRes project. Agricultural irrigation needs based on typical crop rotations were also modelled. Drinking water demand can be estimated using per capita consumption. For dry years, specific assumptions regarding increased demand are applied. A comparison of these water volumes highlights how dry periods, rising water demands, or competing uses can affect the long-term availability of water resources.
In addition, aspects of water quality are incorporated into the assessment. Nitrate and trifluoroacetic acid (TFA) concentrations are simulated for the period 2000–2024 to evaluate potential groundwater contamination and associated risks, for example to drinking water supply.
The innovative character of the demonstrator lies in the integrated consideration of water quantity and water quality within a unified assessment model. By linking direct and indirect groundwater recharge, water demand, and water quality, key stressors can be identified, their impacts assessed, and potential conflicts between water availability and water use revealed. The demonstrator therefore provides a transferable approach for assessing local drinking water resources under future climatic and societal changes.
