ABSTRACT
This chapter deals with the design of pumping systems to lower the water table on construction sites so that civil engineering foundations in excavations below the water table may be emplaced in the dry. The methods of dewatering discussed include sump-and-pump setups, deep wells, well-point systems, and cofferdam-supported procedures for construction in rivers or open water. A lift pump is used to dewater an excavation for the construction of a reinforced concrete foundation footing. Large dewatering systems are most often designed on the basis of team input by hydrogeologists and civil engineers. Permanent dewatering systems are sometimes installed as a design "fix" to protect foundations, prevent the flooding of basements and so on. Mining dewatering systems, although in a strict sense temporary, must be designed for fairly long-term use. Where high inflows are predicted to foundation excavations and/or where these excavations require temporary support, cutoffs are often used in conjunction with dewatering systems.
