The River Poddle Flood Alleviation Scheme is assessing the River Poddle catchment to mitigate against the flooding that results from overtopping of the watercourse and the local surface water network. The watercourse stretches from the Institute of Technology at Tallaght to the outfall at the River Liffey close to Wellington Quay. Within the floodplain, there are about 900 properties at risk of flooding. The project was part of the joint venture between Nicolas O’Dwyer and Binnies, both RSK group companies.
We undertook the modelling of the catchment to understand the existing flood risk and to develop potential options to mitigate against the flooding. Owing to the integrated nature of the catchment, the model included the open watercourse, the surface water network and an allowance for overland flows. The model was calibrated against observed data on the river plus historic events to ensure that the flooding mechanisms were fully understood. Once the existing flood risk was established, a series of mitigation options was tested through the model, and an economic assessment was carried out to determine the preferred option. Consultation was held with South Dublin County Council, Dublin City Council and the Office for Public Works to ensure that the preferred option satisfied all the outcomes required from the project.