City appeals for careful use of water

The prolonged drought last summer led to a particularly significant drop in groundwater levels. For the groundwater level to recover, the rainwater that falls from November to the end of April is crucial. During this time, plant growth is dormant and evaporation is lower than in the summer months due to the lower temperatures. This allows most of the rainwater to seep away. If sufficient precipitation falls, groundwater recharge begins and groundwater levels rise. This recovery phase comes to an end at the end of April. Due to the higher temperatures, the rain then evaporates directly or is consumed by plants. In addition, household water consumption increases in the summer months. As a result, groundwater levels normally fall in the summer months from May onwards, even with average rainfall.

In Offenbach, the past winter half-year from November to April saw fairly mixed rain or snowfall: While February saw the least rain and snow since 2005, the month of March this year saw the most precipitation since 2005. Rainfall in the other winter months was in the average range. Overall, the winter precipitation was not enough to make up for the missing amounts from the previous hot summer. Although it rained more in March than it has for a long time, this does not mean that groundwater levels will recover quickly. A report from the Hessian State Agency for Nature Conservation, Environment and Geology (HLNUG) states that although the levels are currently rising again, it is unlikely that sustainable regeneration will be possible before the summer. In order to compensate for the deficit in groundwater from the previous dry years, abundant rainfall over a much longer period of time and the saving of drinking water are necessary. The Lower Water Authority at the City of Offenbach's Office for the Environment, Energy and Climate Protection is therefore already appealing to people to use drinking water sparingly and carefully so that there are no restrictions for the population in summer.

With the Climate Concept 2035, the city is focusing on medium and long-term measures to prevent the groundwater level from sinking further in the future. For example, the unsealing guideline and the sponge city approach are intended to allow more water to seep into the ground again instead of being drained away via the sewer. This is important for groundwater recharge. The city of Offenbach is also working together with the Zweckverband Wasserversorgung Stadt und Kreis Offenbach (ZWO) to develop a new municipal water concept. The aim is to adapt the use of water to climate change. "Measures are being developed here to save water and increase the use of service water. In this way, the use of valuable groundwater can be reduced," explains Mayor and Head of Environmental Affairs Sabine Groß.

The city of Offenbach has also drawn up a hazard prevention ordinance. It contains requirements for saving drinking water in dry periods and the possibility of, for example, prohibiting the watering of lawns with drinking water or washing vehicles with such water and filling private swimming pools with drinking water. Another measure is the City of Offenbach's stormwater regulations, which have been in force since July 2022. It regulates the handling of rainwater that accumulates on roof surfaces and green underground garages. According to these regulations, owners must ensure that any precipitation can seep away or evaporate. Discharge into surface water is also possible. This measure promotes groundwater recharge.

Sabine Groß concludes: "There are already many ideas, including technical ones, that will have to be implemented in the future in view of the climate crisis. However, we can all help to prevent this from happening in the first place: If we start saving water today, we will help to maintain a stable supply in conjunction with other conservation concepts."

In order to inform citizens in the supply area of the city of Offenbach about the availability of groundwater in the ZWO's extraction areas at an early stage and in a transparent manner, the ZWO is introducing a water traffic light. The water traffic light is intended to sensitize citizens to the careful use of the precious resource of drinking water. The water traffic light is set up at www.zwo-wasser.de.

Everyday tips for saving energy and water can be found on the city's extensive information pages: