ERNie

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Investigation of the use of rain barrels for rainwater retention in a residential area to relieve the sewer during heavy rainfall

Background

In recent years, climate change-related heavy rainfall events and flooding have continued to increase. Particularly in urban areas with a high level of surface sealing, the sewerage system can quickly become overloaded, as large amounts of rainwater run off and flow into the sewerage system. Further settlement in existing structures also makes it difficult to adequately dimension the sewerage system and is often associated with very high costs, as the existing wastewater system has to be adapted and renewed to meet demand. Against this background, there is a massive need for action in dealing with concentrated water masses in order to avoid or minimise their sometimes devastating effects and damage as far as possible. The municipality of Gebsattel is facing precisely this problem due to an old and too small sewer in conjunction with its location in a depression, as the municipality cannot bear the high financial burden of a sewer extension.

Objective

The aim of the ERNie project is therefore to implement an innovative and more cost-effective alternative for relieving the sewer by decentralised storage of precipitation in rain barrels. In consultation with affected residents, cisterns are to be placed on properties that are networked with each other and can be controlled remotely. Filling the cisterns during heavy rainfall should relieve the sewer and reduce the risk of flooding. Firstly, the water flow in the municipality is simulated using a terrain model. This simulation will then be used to calculate the optimum location and volume of the rain barrels. An elaborate communication concept integrates the wishes and needs of local residents.

The "Water infrastructure and digitalisation" research group will initially be responsible for developing the communication concept, which will use questionnaires and interviews to shed light on the willingness of residents to accept the technology. Software for sewer network calculation with integrated rainwater barrels is adapted to the municipality of Gebsattel and model calculations are carried out. Based on these simulations, the municipality receives an elaborated concept for the dimensioning of the cisterns and recommendations for communication with the residents.

How to counter heavy rainfall: Looking for alternatives to channel expansion

Heavy rainfall events and flooding have been on the rise in recent years. Against this backdrop, there is a massive need for action in dealing with concentrated water masses in order to avoid or minimise their sometimes devastating effects and damage as far as possible.