What is the main purpose of a stormwater detention system?

The primary purpose of a stormwater detention system is to manage stormwater runoff by delaying its progress into natural waterways or drainage systems. This controlled release of stormwater helps to mitigate peak flow rates during heavy rainfall events, reducing the risk of flooding downstream and allowing for a gradual infiltration of water into the ground.

While absolute flood prevention is not achievable—since extreme weather events can exceed the capacity of any system—delay in runoff helps manage the impacts and timing of water entering streams and rivers, thus playing a crucial role in flood risk reduction and water quality improvement.

Managing runoff also indirectly supports the environment by reducing erosion and allowing natural filtration processes to occur, contributing to healthier ecosystems. However, the primary function remains the temporal management of stormwater, which is critical in urban planning and infrastructure design to protect communities and natural resources.