Following on from planning level reporting resulting in the conditioning of various surface water management requirements. Southwest Environmental are finalising design of surface water management system for a site in Surrey.

Design of attenuation tank in line with SUDs manual – Outflow requirements are negotiated with local sewer provider Thames Water, and tank capacity is adjusted to minimise capital outlay for developer.

Application is made to Thames Water for Sewer Connection. 

Note: The size of a surface water attenuation tank is based on the peak inflow rates from the site  (the run-off coefficient is taken it to account when calculating this), and the maximum outflow rate. For example a 5 litre per second outflow rate would require an attenuation tank size of 20 cubic meters, whilst a 10 litre per second out flow would require an 8 cubic meter attenuation tank.

As well as the attenuation tank design, a maintenance plan was submitted for it continued upkeep.