by Dave Stalling and Kelly Catlett
As directed by the 2007 state legislature, the California Central Valley Flood Protection Board has recently adopted an ambitious, comprehensive Central Valley Flood Protection Plan to promote integrated flood management. Working closely with California Trout and other partners, Trout Unlimited California (TUCA) and Defenders of Wildlife urged the Flood Board to adopt a plan that protects lives and property, conserves farmlands, and improves fish and wildlife habitat that will benefit anglers, hunters and others.
TUCA and Defenders feel it is critically important that the plan incorporate floodplains, flood bypasses and levee setbacks to give rivers room to expand during high waters. This will not only reduce the risk of catastrophic floods and protect people, but will also increase reliability and quality of water supply by protecting the Delta and recharging groundwater, ensure the certainty of local government decisions regarding matters such as where people can and cannot build, and protect and enhance fish and wildlife habitat and related fishing, hunting and other recreational activities.
With an extensive system of levees and dams, the Central Valley’s two major rivers – the Sacramento and San Joaquin – have long been disconnected from their traditional floodplains. Since these river management systems were first designed more than 100 years ago, research has shown that disconnecting rivers from floodplains increases risks to public safety and causes significant environmental damage, including damage to native fish, wildlife, and plant populations.
California has some of the most highly managed watersheds in the world. The network of levees and dams that regulates floods, generates hydropower, and provides water for urban and agricultural users has essentially disconnected this area from the rivers that run through it. As a result, the Sacramento River Basin is second only to New Orleans in its risk of a catastrophic flood – threatening lives, property, farms, water supplies and native fisheries. Giving rivers access to their natural floodplains and allowing for flood bypasses and levee setbacks will relieve pressure during high water flows and lower the chances of massive property destruction and injury to people. If done right, it also replenishes nutrients in agricultural soils while providing ideal rearing conditions for salmon and habitat for migratory birds and other riparian species.
Research out of the UC Davis Center for Watershed Sciences indicates that when juvenile salmon are given access to floodplains they grow significantly larger, increasing their chances of survival. Rivers that have access to floodplains also help restore native plants, which in turn support native wildlife of all types and benefit native species in the fight against invasive species.
Some of the biggest benefits from reconnecting rivers with floodplains accrue to migratory birds. Birds use floodplains for breeding, nesting, and rearing young. Floodplains provide a source of drinking water and habitat for feeding, resting, shelter, and social interactions. Flooded areas are also an important barrier to land-based predators and reduce the risk of predation to nesting or young birds. Additionally, floodplains provide corridors that allow wildlife to move from one habitat to another, especially in urban areas where development has fragmented alternative travel routes for wildlife.
The Sacramento River at one time expanded to as wide as five miles before dams and levees hemmed it in. Its floodplains sheltered young salmon from the quick river flows and attracted ideal food to help young fish grow quickly. Juvenile salmon that spend time on the floodplain grow faster than those that use only the river channel during their migration to the ocean, according to Carson Jeffres, fish ecologist for the Center for Watershed Sciences. This increase in productivity on the floodplain is because the water is warmer and food is more abundant. Because of the increased growth, the juvenile salmon are larger when they head out to sea and can survive better by swimming faster and avoiding predators. The same warmer water that benefits salmon is also a boon to wildlife. Warm water helps insects and invertebrates grow faster and these are an important food source for waterfowl, as well.
And what’s good for fish and wildlife is good for people. Strong fish and wildlife populations are a harbinger of a healthy ecosystem – a healthy ecosystem that will protect lives, protect farms, protect fish and wildlife and benefit those of us who love to fish, hunt and otherwise enjoy healthy rivers and healthy habitat.
For more information about the flood plan and flood protection board, check out the following site: http://www.cvfpb.ca.gov/CVFPP/