Why do we need to manage stormwater and polluted runoff?

Managing our stormwater aims to improve the quality and reduce the volume of stormwater. Unlike sanitary sewer water, stormwater does not receive any treatment before it enters our waterways, thus delivering pollutants with it that it picks up along the way. This adversely affects wildlife, human health and safety. In addition, water that falls on hard surfaces and doesn't infiltrate into the ground runs off to lower areas, with excess runoff potentially causing local flooding and stream bank erosion.