Federal officials say California’s plan to close some state parks is illegal, KPCC-FM radio reported.

The problem, says the National Park Service, is that 16 California parks accept grants from the U.S. government.

In the last 45 years, California parks have gotten hundreds of millions of dollars from the federal Land and Water Conservation Fund. Those grants essentially are contracts, and closing the parks in question would violate the contract.

One option could be to persuade the National Park Service that “closing” some parks most days a week isn’t the same as entirely shutting them down. State parks officials admit it’s a setback; they didn’t check with the Interior Department before they released a list of parks to close few weeks back. Other state agencies also object.

Some of the parks that have received conservation fund money include Castle Rock State Park in Santa Clara County; Salton Sea State Recreation Area in Southern California; Twin Lakes State Beach in Santa Cruz; Portola Redwoods in San Mateo County; Candlestick Point near San Francisco; Limekiln in Big Sur and Salton Sea State Recreation Area in Southern California.

The head of the California Coastal Commission pointed out last week that the commission must grant permission to close a beach. Besides that, executive director Peter Douglas said, the state constitution makes walking along a wet beach up to high-tide level a public right.

If the state can pull it off, the park closings would save $11 million this year and $22 million next year.