Reservoir Flooding in Northern Ireland (NI)

Flooding from impounded water bodies such as reservoirs and dams can arise as a result of overtopping or failure of the impounding structure which in turn may result in a sudden uncontrolled release of flood water into downstream areas.

Flooding has the potential to cause fatalities and injury, displacement of people and damage to buildings. PPS 15 adopts a precautionary approach to development in areas susceptible to reservoir flooding and Policy FLD 5 states that new development will only be permitted within the potential flood inundation area of a controlled reservoir if the applicant can firstly demonstrate that the condition, management and maintenance regime of the reservoir is appropriate to provide sufficient assurance regarding reservoir safety and secondly that the application is accompanied by a Flood Risk Assessment which demonstrates an assessment of the downstream flood risk in the event of both a controlled and uncontrolled release of water from the reservoir.

We will visit both the site and the reservoir, approach the reservoir owners to ascertain if the reservoir is appropriately managed and maintained and undertake a Flood Risk Assessment to assess the risk of both controlled and uncontrolled flooding to the proposed development.

Our Flood Risk Assessment will also provide for a site specific emergency evacuation plan that can demonstrate the safe access and egress for emergency services and people during times of flooding. We are one of only a few consultancies that have the appropriate software to undertake this study in a manner deemed acceptable to Rivers Agency. In addition, we have a close working relationship with Rivers Agency and have the required experience to achieve a successful outcome.

It is our understanding that at present we are the only consultancy in Northern Ireland that can produce hydraulic modelling of a reservoir failure in order to determine depth and velocity of flooding at a particular site and then offer appropriate mitigation measures.