01/11/2023

City equips itself against heavy rain and flash floods with sensors in the sewer system

The technical solution should help the municipality to act more proactively.

Streets that become raging torrents during heavy rainfall because the sewage system cannot absorb the amount of water: Images like these are closely linked to the devastating storm in the summer of 2021, which devastated parts of NRW and claimed several lives. Since this experience at the latest, municipalities everywhere have been preparing themselves to better cope with such extreme weather situations. "We can't influence the weather, but we can create a kind of advance warning system with technical solutions so that we can act with more foresight," explains Thomas Wedowski, operations manager at Technische Betriebe Dormagen (TBD).

The technical solution consists of sensors. Currently, the first of a total of 30 sensors are being installed in street inlets - so-called sinks - throughout the city. In a pilot operation, the TBD will then test several application scenarios together with the Stadtmarketing- und Wirtschaftsförderungsgesellschaft Dormagen (SWD) in the context of the Smart Industrial City, which will help to improve processes and make savings.

"Routinely, the cleaning of the approximately 9,200 sinks in the urban area takes place several times a year, especially at the end of the year when the leaves fall from the trees. Over the study period of more than a year, we expect to gain insights into whether the current cleaning intervals can be optimised," explains Moritz Rechenberger, Head of Urban Drainage at TBD. Another effect is that overflow events during rainfall can be read from the measurement data. From this, in turn, measures can be derived in the best case that could increase the resilience of the infrastructure during heavy rainfall.

The sensors record the level of the sinks at defined intervals. The data is transmitted via LoRaWAN gateways - radio networks - to the TBD's sewer information system and, in the further course, also to the Urban Data Platform (UDP), which is currently being prepared for this purpose. The aim is to identify correlations between environmental characteristics and filling velocities of the sinks.

"Within the UDP, we then want to bring the measurement data together with other data sets. These include weather data or Rhine level gauges, for example. The combination of all data should help us to better manage heavy rainfall events locally. From the totality of data from sensors, weather data and heavy rain hazard maps, areas at risk of flooding can be better defined in the future. As a result, early sensitisation of the population and emergency services is possible," says André Heryschek, Head of Structural Change and Smart City at SWD, giving an insight into the practical benefits of the data model.

Kanal-Netz GmbH from Meerbusch is accompanying the pilot project. Managing Director Elisabeth Schloten is looking forward to being able to use the data for possible AI models. The project is supported by CHEMPARK operator CURRENTA, which will also be contributing its own data from groundwater and Rhine level measuring stations as the project progresses. "We are sharing data with each other and, of course, also the insights gained from the pilot project, so that all sides will benefit," emphasises SWD Smart City Manager Christoph Reitenberger.