Circulation and Physical Processes within the San Gabriel River Estuary During Summer 2005

摘要

The San Gabriel River (SGR) is one of many rivers in the coastal lowlands of southern California that has been extensively modified in an effort to control flooding during the winter season. The river flows from the San Bernardino Mountains, north of Los Angeles, southward toward San Pedro Bay, and empties into the bay just east of the Ports of Los Angeles/Long Beach. Most of the river in the lowlands is lined with concrete, up to within 6.5 km from the coast. At this point the concrete river bed ends, and the tidally dominated river estuary begins. The river banks have been reinforced with rock rip-rap, and the river bed is mostly sandy bottom. This 6.5-km stretch of the river leading to the ocean is commonly referred to as the SGR estuary. There are two natural-gas power-generating stations (PGS), one on either side of the river, with several units each. The plants require cooling water, for which the plant on the west side draws seawater from nearby Alamitos Bay, while the plant on the east draws from a channel leading to the ocean. This cooling water is subsequently discharged into the SGR at several points along the estuary at a slightly warmer temperature. There has been concern in the local community about water quality within the estuary, which has initiated studies on the causes of potentially degraded water quality.