The design of site control measures is covered in 'The SUDS Manual', CIRIA C753, 2015. See also
for further details of SUDS measures.
Some site control techniques are examined in more detail below.
The outflow from a detention basin is via a control such as an orifice which is designed to limit the peak flow passed downstream. Flow in excess of
the limiting discharge is stored within the detention basin until such time as the storm has abated and will then be gradually allowed to drain away through
the basin's outlet. The design of the outlet control needs to take into account the possibility of blockage due to rubbish or dead vegetation, etc clogging
the orifice. Consideration also needs to be given to the operation of the basin during a severe storm which exceeds the basin's design criteria.
An option for sites with restricted space is an underground tank which fulfils the same function as a detention basin but which can be positioned under a
road or car park.
Constructed wetlands are in many ways similar to detention basins except that the floor of the basin provides a site for a shallow pond with
appropriate vegetation to improve pollution removal and to provide a wildlife habitat.
Again infiltration basins are similar to detention basins but the outflow from the basin is via infiltration into the underlying soil.