The purpose of flow control in an attenuation tank is to store water and prevent overwhelming storm sewers and drains. It slows down the flow of water exiting the tank, ensuring it is slower than the incoming flow. This gives the tank time to drain gradually and prevents flooding or backup issues downstream.
Flow control devices come in different types. For smaller tanks, a simple orifice plate with a smaller hole than the incoming pipe can be used. Larger tanks may utilise bespoke vortex flow controls designed to match the tank’s dimensions and flow rates. These devices create a swirling motion to slow down the water, and their size is determined to match the capacity of the downstream system.
Overall, flow controls are crucial in regulating the water flow and ensuring it doesn’t exceed the capacity of the drainage system.
