RiskPlus in use at Stadtwerke Clausthal-Zellerfeld

The new Drinking Water Catchment Areas Ordinance (TrinkwEGV) and the amended Drinking Water Ordinance (TrinkwV) require water suppliers to implement systematic risk management - combined with high technical and organisational requirements. Stadtwerke Clausthal-Zellerfeld GmbH addressed the issue of implementation at an early stage and decided in favour of the RiskPlus software solution. In close cooperation with the TZW: DVGW Technology Centre for Water, they have already successfully implemented key steps.

Coordination with authorities and neighbouring suppliers

The municipal utility company's drinking water supply comes from surface waters and springs in the Harz Mountains - including historic reservoirs. Responsibilities and interfaces were already clarified in the first stage of the project. The neighbouring water supplier Harzwasserwerke maintains the drinking water ponds, while Clausthal-Zellerfeld municipal utilities are responsible for the areas of the designated water protection zones of Hirschler Teich and Kellerhalsteich. A special feature: separate protection zones have not been designated here, as the areas border on the catchment areas of the Sösetalsperre and Innerstetalsperre dams and are covered by their protection zones III.

Reaching the goal together: RiskPlus, TZW and local knowledge
The area descriptions were created, hazards analysed and risks assessed in four joint online workshops with TZW. The municipal utilities contributed their local knowledge, while TZW provided methodological, organisational and technical support.

RiskPlus played a central role in this: the software enabled structured processing - from land use analysis to risk prioritisation. The protective effect of the catchment area was automatically integrated into the risk assessment. The risks in the catchment area could all be analysed and evaluated. The results can be easily output in the required structure, as described in the „Minimum requirements for risk assessment“ guidelines issued by the German Working Group of the Federal States on Water Issues (LAWA). An additional plus: the analyses and maps can also be used in everyday operations.

In March 2025, Stadtwerke Clausthal-Zellerfeld was able to finalise the new requirements of the TrinkwEGV with the help of RiskPlus. The software also impressed with its intuitive user interface, GIS-supported processing and the large number of data bases already stored. The project shows: RiskPlus offers an effective solution for risk management in the public water supply sector, even for complex catchment areas. Stadtwerke Clausthal-Zellerfeld is relaxed about the deadline for submitting the digital documentation to the authorities in November 2025.

You can find out more details about the practical implementation in the Upper Harz catchment areas of Stadtwerke Clausthal-Zellerfeld here.