W

Wallingford procedure
A design and analysis procedure for urban drainage networks (HR Wallingfor and Institute of Hydrology, 1981a).

washoff (of pollutants)
The transport of pollutant mass from the catchment surface during a rainfall event.

wastewater
Water used and discharged to drain.

water quality
The chemical, physical and biological characteristics of water with respect to its suitability for a particular purpose.

water quality standards
Standards set by the national legislation or European Community directives and enforced by regulatory authorities in member states.

water-table
The surface within soil or rock strata at which groundwater saturation occurs.

Water UK
The organisation representing all water supply companies in the UK.

watercourse
A natural or artificial channel for passage of water.

weir
An overflow structure across a channel that may be used for controlling upstream surface level, or for measuring discharge, or for both; usually horizontal and constructed as either broad- or sharp-crested.

wet well
The entry chamber in a pumping station from which water is pumped to a higher level.