Floodplain Restoration

A Multi-Benefit Strategy for a Warming Climate

The dramatic failure of the spillway at Oroville Dam and the evacuation of 188,000 downstream residents highlight the importance of effective flood management in California.  After years of drought, Californians are suffering from water whiplash, with the current swing from drought to flood conditions.

If you think something strange is happening here, you’re right.  The last seven years have included a wet 2011, five years of drought (2012-2016) – four of which were the driest four-year period in state history – and now an extraordinarily wet 2017.

This fluctuation from wet to dry – without anything approaching average conditions – is consistent with the projections of climate scientists.  In 2011, the State of California warned “(a)s the climate warms, extreme events are expected to become more frequent, including wildfires, floods, droughts, and heat waves.”

You don’t need to make a trek to the arctic to see on-the-ground impacts of climate change. Californians can simply look to their local rivers or the Sierra Nevada.  The Sierra snowpack is now the largest in two decades – 177 percent of average.  This comes just two years after a record low snowpack that was only 6 percent of average.  Californians are already seeing more extreme weather events.

The last five years taught Californians that we need to make conservation a way of life and that we must invest in tools like water recycling that are drought resilient.  This year – and the weather patterns of the past seven years – teach us that California must prepare for floods as well.

How can we best do that?

One of the best ways is to restore portions of our historic floodplains to increase the ability of our rivers to handle high flows.  We’ve seen the flood-protection benefits of floodplains this year.  By opening gates to the Yolo Bypass floodplain, flood managers have lowered the risk to the cities of Sacramento and West Sacramento, and avoided potentially catastrophic flooding.

In addition to protecting residents from flooding, floodplain restoration projects provide a surprisingly long list of other benefits.  For example, when water is allowed to inundate floodplains, juvenile salmon thrive – growing far fatter and healthier than in nearby rivers.  Floodplain restoration also benefits songbirds, shorebirds, waterfowl and many endangered species.

In fact, researchers at UC Davis have shown how improved management of the Yolo Bypass can improve flood protection while benefitting salmon, migratory water birds, and maintaining agricultural production.

There are many other places in California’s Central Valley where floodplain restoration offers similar promise, such as Paradise Cut on the lower San Joaquin River.

To call floodplain restoration a “win-win” approach falls about a half dozen “win’s” short of a fair description of the ways in which it can benefit California and its wildlife.   The Oroville Dam crisis and the floods of 2017 provide a “teachable moment” and an opportunity to invest in floodplain restoration projects that protect our cities from flooding – and along the way restore wildlife, endangered species, salmon runs and more.

Defenders is working hard to invest in this type of smart, wildlife-friendly infrastructure in California. Whether it’s promoting projects to reconnect our rivers and streams to their natural floodplains, or advocating water-storage solutions to replenish underground aquifers, Defenders is committed to advancing the most scientifically sound, wildlife-friendly solutions to the water challenges facing California now and into the future.

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