Refuge Water Supply Program

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The Refuge Water Supply Program (RWSP) is a U.S. government effort to protect and restore wetland habitats in California’s Central Valley. Run by the Department of the Interior, it is managed by the Bureau of Reclamation and the Fish and Wildlife Service. Since 1992, the program has a mandate to acquire and deliver a total of 555,515 acre-feet of water each year to 19 protected wetland areas.

Why the RWSP exists
Before the program, the Central Valley lost most of its natural wetlands, reducing habitat for resident and migratory birds and other wildlife. The Central Valley Project Improvement Act (CVPIA) of 1992 was created to fix some of these problems by increasing wetland habitat and helping fish and wildlife populations recover.

How the water is organized
- Full Level 4: The target amount of water needed for each refuge, consisting of two parts—Level 2 (base water) and Incremental Level 4 (IL4) (additional water to expand wetlands).
- Level 2: A stable base amount delivered to refuges mainly through the Central Valley Project (CVP). This ensures refuges have essential water every year.
- Incremental Level 4 (IL4): Extra water to fully develop and manage wetlands. Unlike Level 2, IL4 must be bought or sourced from other providers and is less predictable.
- Across all 19 refuges, the combined Full Level 4 amount adds up to 555,515 AF per year. On average, about 75% to 85% of Full Level 4 is actually delivered each year, because some refuges lack the infrastructure to receive all the water or other constraints apply.

The 19 refuges the program supports
These include units in the Sacramento National Wildlife Refuge Complex (Sacramento NWR, Delevan NWR, Colusa NWR, Sutter NWR), the San Luis National Wildlife Refuge Complex (San Luis Unit, West Bear Creek Unit, East Bear Creek Unit, Kesterson Unit, Freitas Unit, Merced NWR), the Kern National Wildlife Refuge Complex (Kern NWR, Pixley NWR), and several Wildlife Areas such as Gray Lodge WA, Los Banos WA, North Grasslands WA, Mendota WA, and Volta WA. Some refuges are part of larger complexes, and a few units belong to state land as well.

How water moves to the refuges
Water is delivered through a network of canals and channels owned by many entities. The RWSP signs long-term contracts to convey water from the CVP or other sources to each refuge. Some water can move with little or no cost, while other portions require payments. Water losses occur during conveyance (evaporation, seepage) and can be significant, sometimes moving water hundreds of miles from source to refuge.

What IL4 water is for and where it comes from
IL4 water is intended to allow refuges to manage wetlands more fully and expand habitat. While Level 2 water is reliably provided from federal supplies, IL4 water is more variable and is often purchased or secured from willing sellers, exchanges, or other agreements. The RWSP works to acquire these supplies and arrange conveyance, but availability and cost can vary.

Key projects and partnerships
To ensure a steady supply, the RWSP funds and manages various contracts to convey water through federal, state, and private systems. A notable example is the North Valley Regional Recycled Water Program, which provides treated recycled water from local cities and, under a 40-year contract signed in 2016, delivers water to the refuges.

What the program has achieved
- Since CVPIA, there has been a significant expansion of wetland acreage and improvements in habitat quality.
- Wetlands receive more reliable water through all seasons, supporting waterfowl, shorebirds, and other wildlife throughout the year.
- Healthier wetlands have helped reduce disease and improve water quality by enabling better flow and nutrient management.
- Some indicators show substantial growth in waterfowl use and habitat for species such as giant garter snakes and tri-colored blackbirds.

Funding and future challenges
The CVPIA and RWSP rely on annual federal funding. The program has been estimated to need roughly $50–60 million per year to fully meet its goals, but actual appropriations have varied (for example, about $22 million in 2017). Drought, climate change, and uncertain IL4 supplies pose ongoing challenges to maintaining and expanding these wetlands. The RWSP continues seeking reliable sources and efficient delivery methods to keep refuges healthy into the future.