Water is essential for all life, but as human populations have grown, water has been harnessed to support people and not nature. As a result, freshwater species have declined at twice the rate of land or ocean species globally. Add climate change to this equation, and you have a massive global water challenge.
California is a microcosm of water issues around the globe. Like California’s economy, much of our state’s remarkable biodiversity depends on one of the most highly altered hydrological systems on earth. Engineered over the past 150 years to meet the needs of people, the water system today is now struggling to do even that. It is one of the most oversubscribed water systems in the world. And climate change is making matters even worse, as, every few years, we swing between drought and deluge—making water availability very unpredictable.
Nature has fared even worse: In our children’s lifetimes, more than half of California’s native freshwater plants and animals, and most of the wildlife species that are only found in California, could disappear forever.
Our team is working to change this trajectory.
The Nature Conservancy is using innovative tools, including science, technology, policy, market-based solutions, and on-the-ground projects, to ensure water is managed more sustainably. To do this, we’re working with farmers and ranchers, universities, technology companies, public agencies, and drinking water advocates to test and implement new solutions that can meet the water needs of nature and improve water supply reliability for people, stretching and sharing every drop. We are demonstrating what innovative and sustainable water management looks like—not only for California, but for the world.
In California and around the world, rivers are the lifelines of our natural and human communities. Flowing throughout our state’s deserts, redwood forests, Sierra mountains, and great Central Valley, California’s rivers provide a home for thousands of freshwater species, supply drinking water to more than 30 million Californians, and are a significant water source for our $40 billion agricultural economy. They were also once home to many of the largest salmon migrations on the Pacific Coast—with seasonal runs in coastal rivers and the Central Valley numbering in the hundreds of thousands—a natural phenomenon that has dwindled to a trickle.
People are using too much water, especially when water is the most scarce during the summer. By taking huge volumes of water directly from our rivers and by storing large amounts behind dams, we’ve severely altered how much water is flowing in our rivers and when. The amount of water in our rivers naturally varies from season to season throughout the year—and species like salmon and steelhead have evolved according to this fluctuation. But human alteration has left few resources for even the best drought-adapted species. At its worst, overuse and inefficient management are drying up some rivers during the summer, leaving nowhere for river-dwelling species to go.
The good news is that in many cases, by being more efficient with our water use and dynamically managing when we take water from rivers, we can meet the needs of both people and river ecosystems. To overcome the challenges our rivers face, we are:
Using our science and working with partners to, for the first time in California history, determine how much water is needed in our rivers to support wildlife, for all rivers in the state and for all months in the year. And we are using these thresholds to influence policy.
Supporting on-the-ground river flow projects, such as community-level collaboration among water users, using techniques like water storage and changing the timing of diversions. We then proliferate these techniques statewide using a network approach.
Buying our own water that we can choose to leave in the river for fish, or transfer to farms and wildlife refuges to create habitat for birds.
Through these approaches, we are helping bring water security to people and ensuring enough water is left in rivers at the right times so salmon, steelhead, and other river species can thrive. Since 2009, we have worked with partners to restore seasonal flow patterns to four rivers that are critically important to salmon and have purchased or facilitated over 26,000 acre-feet (over 8.5 billion gallons) of water to be left in rivers to support wildlife. This work complements TNC’s legacy of river habitat conservation for salmon and steelhead on over 5,000 river miles statewide.
Thriving Birds and Wetlands
California’s Central Valley used to be a 10 million-acre wilderness, dotted with over 4 million acres of lush wetlands. These wetlands made it prime habitat for tens of millions of birds on their yearly migration along the Pacific Flyway, from the taiga of the Arctic to the coastlines and forests of South America.
Today, more than 95% of those wetlands have disappeared, lost to farmland, urban sprawl, and an overburdened water system. Only about 200,000 acres of seasonal wetland remain, contained within a relatively small but critical number of public and private refuges. Unfortunately this habitat is not enough to support the millions of migratory birds that fly through looking for a place to land.
Many species that once depended on these vast wetlands at key times of year, are now in deep trouble. Shorebirds, of which there are over 25 species that migrate through California, are particularly imperiled. California is considered to be one of the top 20 most threatened bird habitats in the country, and shorebird populations have declined by almost 40% in just the last 50 years. Their remaining habitat is at risk with predicted increases in the frequency and severity of drought. Even in very wet years, suitable habitat is not always available when birds need it.
Fortunately, we’ve been hard at work piloting and implementing approaches to support the wetland habitat we have left and creatively use farmland to fill the habitat gap. To create enough habitat for migrating shorebirds, we are:
Purchasing and delivering water to farmland and existing public wetlands.
Creating “pop-up” wetlands for birds on farmland—essentially, Airbnb for birds—using big data and a reverse auction market to select the highest value habitat, and proliferating this technique using a network approach.
Building on this “pop-up” model to replenish underground aquifers, leading to benefits to birds, as well as farmers and people who rely on groundwater.
Since 2014, we have partnered with farmers to create over 60,000 acres of high-quality, seasonal habitat, used by over 1 million migratory birds. Through the scaling of these approaches, we will seek to create 350,000 new acres of habitat annually by 2050 so that California’s shorebird populations, and the Pacific Flyway at large, can grow and thrive.
Sustainable Water Supplies
Aquifers underground formed over millions of years. They are now one of the primary freshwater sources in California. About 85% of Californians depend on this underground water (known as groundwater) for some portion of their water supply. In a wet year in California, aquifers provide 40% of the water people use—in dry years, that number jumps to 60%. These percentages are even higher in the agricultural Central Valley and Central Coast. People pump this water out of the ground for drinking and irrigation, and native plants stretch their roots down deep to reach the water, creating wildlife habitat.
Unfortunately, in many places, people are pumping this groundwater faster than rain can replenish it. Along with droughts, the unsustainable pumping of groundwater is leading to drinking water shortages and declining water quality for disadvantaged communities. Dying crops, habitat loss, and species extinctions are also unfortunate side effects. In some areas, land has even sunk by up to 30 feet.
Fortunately, with the support of TNC, California passed the Sustainable Groundwater Management Act, which, for the first time, limits the amount of groundwater that can be pumped, in the most affected parts of the state. The Act requires that local water agencies devise plans to stabilize their groundwater pumping, and thanks to TNC’s influence, it is one of only four pieces of legislation in the world that require nature’s groundwater needs to be considered alongside people’s.
TNC is working to ensure that plans go beyond lip service and achieve actual sustainability. To do this, we’re providing feedback to the State on how well the submitted plans address the water needs of nature and the drinking water needs of disadvantaged communities. We’re also piloting solutions that simultaneously benefit wildlife, farmers, and disadvantaged communities, and making these solutions available to local water agencies that need to deliver on their sustainability plans. These solutions include:
Decreasing groundwater demand by creating markets to trade groundwater and strategies for restoring parcels of farmland to habitat where it most benefits wildlife.
Increasing groundwater supply through groundwater replenishment.
Finally, given that groundwater is a primary water source in locations outside the Central Valley as well, TNC is working to expand sustainable groundwater management policies to cover the entire state.
Our goal is to sustain 3.6 million acres of groundwater-dependent ecosystems by 2050, providing habitat for more than 1,500 species of plants and animals. Through all this work, we will enable sustainable groundwater-use that gives people a reliable and resilient water supply, while also allowing groundwater-dependent wildlife to flourish.