The Sweetwater Dam is a dam across the Sweetwater River in San Diego County, California. It is located approximately 12mi east of San Diego, 9mi and borders Bonita to the southwest and La Presa to the northeast. The 108ft-high masonry arch dam impounds 960acre Sweetwater Reservoir.The dam was first constructed in 1888 as part of a system of reservoirs on San Diego County rivers designed to provide water to irrigate crops along the coast and to supply the city of San Diego and its outlying towns. Over the next few decades the dam was raised and retrofitted several times from its original height of 60ft. In 1916, a heavy flood caused both abutments of the dam to fail. Fortunately, the rest of the dam did not sustain heavy damage and it remains in use today serving flood control, water storage and recreation.DesignSweetwater Dam is a concrete thick gravity-arch type, straddling the Sweetwater River to form a reservoir capable of holding 28079acre.ft of water. It is 108ft high and 700ft long, with a thickness of 46ft at the base. It is equipped with an intake tower on the upstream end connected to a high-pressure conduit that cuts through the base of the dam designed to release water from different depths of the reservoir; if water is released from a lower elevation the outflow will be greater. However, due to the low flow of the river, there is typically only a trickle of water below the dam as it impounds all the inflow from upstream. Occasional large floods do hit the area, so the dam is designed to survive overtoppings and also has a pair of seven-gated spillways capable of handling more than 45000cuft/s.
