Retention of stormwater runoff is mainly provided through underground tank systems or retention ponds. Detention helps with attenuation of rainwater during peak flow and can also help with filtering and sedimentation, contributing to water quality improvement. Factors, such as space availability, durability, whole life cost, maintenance costs and prospects for adoption by water authorities, are usually used to determine what attenuation and retention option to go for. There is information about the benefits of precast attenuation tanks here (>Link to “Why Precast” page).
