The addition of impermeable surfaces will lead to an increase in the quantity of surface water run-off, which can overload the drainage system/ downstream watercourse and lead to potential flooding .

One particular solution to manage and control surface water runoff would be to temporarily store excess water in an underground Stormbloc or Stormcell attenuation facility. The forward flow off-site can be accurately controlled with the use of a Hydro-Brake Flow Control to match the pre-developed hydrology of the site.