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.