definition

A flood control dam is a dam built to catch surface runoff and stream water flow in order to regulate the water flow in areas below the dam. Flood control dams are commonly used to reduce the damage caused by flooding or to manage the flow rate through a channel.
(Wikipedia, Detention dam, accessed on Sept. 2016)
In general, dams are multipurpose, therefore even when their main purpose of construction is different e.g. irrigation, water supply, hydro power etc., they always assist in flood protection due to the temporal regulation of flow they provide. (ICOLD, Role of Dams, accessed on Sept. 2016)

Co-benefits and impacts

Flood control dams can also assist in replenishing groundwater and trapping sediment. Co-benefits might also be hydro power generation, irrigation, human consumption, industrial use, aquaculture and navigability.
(Wikipedia, Detention dam, accessed on Sept. 2016)

conditions

Dams and reservoirs can be effectively used to regulate river levels and flooding downstream of the dam by temporarily storing the flood volume and releasing it later. The most effective method of flood control is accomplished by an integrated water management plan for regulating the storage and discharges of each of the main dams located in a river basin. Each dam is operated by a specific water control plan for routing floods through the basin without damage. This means lowering of the reservoir level to create more storage before the rainy season. This strategy eliminates flooding. The number of dams and their water control management plans are established by comprehensive planning for economic development and with public involvement. Flood control is a significant purpose for many of the existing dams and continues as a main purpose for some of the major dams of the world currently under construction.
(ICOLD, Role of Dams, accessed on Sept. 2016)

Related Links

---

Last modified: Sept. 19, 2016, 10:02 a.m.