Greenfield Run-off

Greenfield run-off is the surface water drainage regime from a site prior to development, or the existing conditions for brownfield redevelopment sites. To maintain the natural equilibrium of a site, the surface water discharge from a devloped site should not exceed the natural greenfield run-off rate. The Environment Agency will often advise on allowable discharge rates to watercourses for sites that are to be developed. However, where possible it is avised that surface water is managed at source where possible.