Wetlands in the Central Valley of California are the backbone of the Pacific Flyway. These wetlands, along with flooded agricultural fields, support 60 percent of California's migratory birds as they journey to wintering and breeding grounds.
The Central Valley used to be a vast mosaic of seasonal wetlands, permanent wetlands, upland, and riverside forests that supported a diversity of wildlife.
But today, the situation is dire. Over 90 percent of wetlands in the Central Valley have been destroyed. The number of birds in North America have dropped by one-third over the past fifty years, likely due in large part to loss of suitable habitat.
This makes the remaining wetlands in the Central Valley even more important because of what has already been lost in bird populations, ecosystem function, and recreational opportunities. Waterfowl and shorebirds migrating through the Central Valley today are surviving off of isolated, postage stamps of wetlands across a landscape of agriculture and urban development.
As California addresses its decades-long pattern of groundwater overuse, special protections are needed for wetlands that depend on groundwater. Because of the damming of California’s rivers for development, agriculture, and flood control; wetlands in the Central Valley are disconnected from natural water sources and maintained through applied water. Surface water delivered through a series of aqueducts and canals or groundwater pumped from local wells is applied to shallow ponds to create flooded wetland habitat.
Central Valley wetlands are managed wetlands and are, therefore, tied in closely with state and local water management systems and management decisions. We must ensure that they have the water they need to create this habitat.
Groundwater pumping has been almost entirely unregulated throughout California’s history, leading to a race to the bottom that pitted neighbor against neighbor to dig the deepest well and pump the most water for short-term gain.
In 2014, in the midst of a historic drought, the California Legislature passed the Sustainable Groundwater Management Act (SGMA) to finally bring California on par with other western states, requiring sustainable groundwater management by 2040. Local Groundwater Sustainability Agencies (GSAs) are now required to develop Groundwater Sustainability Plans (GPSs) to chart a course to 20-year sustainability in overdrafted basins.
The first set of GSPs were submitted to the State in January 2020 for critically overdrafted basins, primarily in the San Joaquin Valley and Salinas Valley. Audubon reviewed eight of these plans with large managed wetland complexes and found they largely fell short in their consideration of managed wetlands. Several plans didn’t accurately identify managed wetland areas and seven of eight plans did not include managed wetlands as a distinct water use sector in their water budgets, as required by SGMA regulations.
We must allocate sufficient groundwater to managed wetlands or this will spell disaster for migratory birds.
State oversight is needed by the Department of Water Resources and the State Water Resources Control Board to ensure that California’s last, precious wetlands are protected in the process of long-overdue water management fixes. As Groundwater Sustainability Agencies implement groundwater allocations to curb over-pumping, managed wetlands that rely on groundwater need consideration as a public trust resource and the State should ensure they have adequate water supplies.
Central Valley wetlands provide habitat to millions of migratory birds and public lands for all Californians. We must dedicate sufficient water to sustain this vital resource.