ABSTRACT
Pumping facilities have to be provided for water supply if economical gravity systems cannot be constructed. Most large pumping stations abstract water from surface sources such as rivers, canals, lakes, etc., whereas groundwater abstraction is usually provided by smaller (usually submerged) pumping units. Sometimes pumping installations may have to be provided to pump surface water (low-lift drainage installations) behind a dyke (e.g. cofferdam enclosure) or from a shallow sump. High-lift drainage pumps may sometimes be arranged in a grid pattern covering a large area which needs to be drained (e.g. lowering a water table). Pumping installations may be needed to pump sewage or storm sewer flows from low-level networks to high-level screening–treatment plants. Booster pumps may be needed in water supply networks to boost pressure heads. Reversible pump–turbine units are utilized in pumped storage hydroelectric schemes. In all of these cases, different types of pumps with appropriate sump and intake arrangements at the abstraction point are used to transfer the liquid from low to high levels.
