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ECONOMIC DESIGN OF FLOOD‐ATTENUATION RESERVOIRS FOR URBAN AREAS EXPLOITING CATCHMENT HYDRODYNAMICS IN SOUTH‐WEST UK
Author(s) -
Faulkner B. L.
Publication year - 2003
Publication title -
water and environment journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 37
eISSN - 1747-6593
pISSN - 1747-6585
DOI - 10.1111/j.1747-6593.2003.tb00446.x
Subject(s) - tributary , surface runoff , flood myth , attenuation , environmental science , hydrology (agriculture) , channel (broadcasting) , drainage basin , hydraulic structure , urban area , flood mitigation , water resource management , civil engineering , geography , geology , geotechnical engineering , computer science , engineering , telecommunications , ecology , physics , cartography , archaeology , economy , optics , economics , biology
Runoff from new development in urban areas tends to increase the downstream flood peak which has to be attenuated or accommodated in the river channel to avoid increases in flood risk. The built environment close to the river often makes river‐improvement works difficult, if not impossible. This paper introduces the concept of rising‐limb attenuation, to mitigate downstream flood risk — especially in urban areas. Relying on the implicit difference in runoff times of concentration between rural and urban areas, it is possible to design efficient, self‐regulating storage structures, to counteract increases in peak flow in the main urban watercourse, by attenuating the later contribution from less urbanised or rural tributaries. Because rising‐limb attenuation is partial and temporary, volumes of storage are much less than for conventional attenuation reservoirs, with consequent savings in land take and costs. Because the controlled flow is also less, the associated structure is also generally smaller and simpler. Implementations of this type of structure have been carried out in two locations in the UK, and the outline design of these structures is described by reference to a case study.