Friant Dam - Environmental Impacts

Environmental Impacts

By diverting most of the San Joaquin River for irrigation, the Friant Dam has caused about 60 miles (97 km) of the river to run dry except in high water years when floodwaters are spilled from the dam. The desiccation of the river has caused the degradation of large stretches of riverside habitat and marshes, and has nearly eliminated the historic chinook salmon run that once reached about 15,000 fish each year. Reduction in flows has also increased the concentration of pesticide and fertilizer runoff in the river contributing to pollution that has further impacted aquatic species.

On September 13, 2006, after eighteen years of litigation, environmental groups, fisherman and the USBR reached an agreement on releasing part of the water currently diverted into the irrigation canals into the San Joaquin River in order to help restore the river and its native fish and wildlife. The first water was released on October 2, 2009 at a rate of 185 cubic feet per second (5.2 m3/s). By 2014, these "restoration flows" will be increased to 302,000 acre feet (373,000 dam³) per year, or 417 cubic feet per second (11.8 m3/s), on top of the 117,000 acre feet (144,000 dam³) that is currently released for agricultural purposes. However, the river restoration project will cause a 12–20% reduction in irrigation water delivered from Friant Dam.