On Wednesday, federal fisheries regulators approved a controversial plan to allow for increased pumping from the Sacramento-San Joaquin Delta this fall. Facing opposition from environmental groups, the U.S. Fish and Wildlife Service (USFWS) signed off on the proposal that was championed by the U.S. Bureau of Reclamation and Southern California water interests. With those seeking more water for drought-parched farms and cities, the proposal allows for an additional 400,000 acre-feet (or around 130 billion gallons) to be pumped and shipped through the Delta to farms and cities in the Silicon Valley, Southern California and the San Joaquin Valley. If not for this pumping, the water would flow on a natural course to the Pacific Ocean.

With one of the wettest winters on record for Northern California, most of the state’s reservoirs have been filled and the Delta water pumps have been at full tilt for the first half of the year. However, even with this abundance of water, the dispute has continued between farms and cities wanting to receive more water and environmental groups fighting for the delta smelt, a small, finger-length fish that lives only in the San Francisco Bay and the Sacramento-San Joaquin Delta. Doug Obegi, a senior attorney for the Natural Resources Defense Council in San Francisco, argues that this plan will critically endanger the delta smelt at unnecessary risk when an abnormally wet year would otherwise give the fish a break. In the 1970s, these fish numbered in the millions but in recent years, biologists have only been finding handfuls of the fish during Delta trawling surveys. On the other hand, contractors argue there is enough water this year to allow for more pumping and that pumping reductions haven’t been proven to help the smelt.

The regional director of USFWS, Paul Souza, stated that the agency believes this plan strikes a balance between this year’s water needs for wildlife, agriculture, and municipalities. However, environmental groups continue to argue it does not provide enough water as required under federal regulations to feed habitat for critically endangered delta smelt. The Natural Resources Defense Council has noted that it and other environmental groups are considering whether to challenge the action in court.