A sailor’s long-running fight over a San Francisco Bay island could resolve a Clean Water Act question the US Supreme Court has yet to answer—whether tidal channels and adjacent wetlands qualify as protected US waters.

If allowed to move forward, the case, US v. Sweeney, in the US Court of Appeals for the Ninth Circuit, would clarify the scope of the US Supreme Court’s 2023 ruling in Sackett v. EPA, which reduced the wetlands and waterways that qualify as waters of the US, or WOTUS. It would determine the extent of Clean Water Act jurisdiction over tidal wetlands, ditches, and other waterways along the West Coast, and possibly beyond.

The nearly decade-long legal battle that has unfolded in both state and federal courts focuses on a landowner and sailor’s unpermitted levee construction on the 29-acre Point Buckler Island, part of a tidal marsh in the northern San Francisco Bay in Solano County, Calif. The island and surrounding wetlands are important for numerous wildlife, including delta smelt and Chinook salmon.

Damien Schiff, the Pacific Legal Foundation lawyer who argued Sackett before the Supreme Court, sees this case as “the first opportunity for the Ninth Circuit to address the scope of Sackett.”

Schiff filed an amicus brief in the case, arguing waters on the island aren’t under Clean Water Act jurisdiction following Sackett. The federal government so far has held the view that the island’s waters are under its jurisdiction.

Sweeney is an important case to watch because it’s the first case that applies Sackett specifically to tidal waters, said Larry Liebesman, a former Justice Department attorney who is a senior adviser for environmental permitting firm Dawson & Associates.

“Prior cases that have addressed Sackett and WOTUS have all been dealing with non-tidal wetlands,” he said.

The case is being briefed as the Environmental Protection Agency considers public comment on its proposed rule updating the federal definition of WOTUS to comport with Sackett. The Biden administration wrote its own regulation after the ruling, but the Trump administration rescinded it.

Years-Long Litigation

Sweeney is an appeal of a February ruling in litigation filed by the Obama administration in 2017 in the US District Court for the Eastern District of California. The court found landowner and sailor John Sweeney violated the Clean Water Act when he built a levee around Point Buckler Island.

Sweeney bought the island for duck hunting in 2011 and later excavated trenches and built a levee without a federal dredge-and-fill permit. The island included natural tidal channels and ditches that opened to the navigable waters of the bay, which the Justice Department said Sweeney completely closed off.

The Obama administration claimed the entire island as a “traditional navigable water” and said it included wetlands that were “adjacent” tidal waterways.

In Sackett, the justices ruled that for waterways and wetlands to be protected under the Clean Water Act, they have to be “relatively permanent,” and have a “continuous surface connection” to and be “indistinguishable” from navigable waters.

The district court in a 2024 order didn’t apply those standards in its ruling against Sweeney because the court determined that the island’s wetlands merely “abut” tidal channels without a continuous surface connection, Schiff said in his brief.

Dry Land

The lower court also didn’t analyze whether tidal channels are “relatively permanent” and “indistinguishable” from the surrounding bay as Sackett requires, so the Ninth Circuit should vacate and remand the ruling, he said.

Some of island is totally dry and can’t qualify as wetlands after Sackett, he said.

“The District Court noted that some of Point Buckler Island could be considered wetlands so long as water was found in the upper twelve inches of soil,” Schiff said in the brief. “But if one must dig twelve inches to locate water, this necessarily means the wetland lacks surface water and, thus, cannot possibly have a continuous surface water connection to a relatively permanent water.”

The Trump administration in November moved to hold Sweeney’s appeal in abeyance in part because he no longer owns the island. The Solano County sheriff in January auctioned off the island under a state court order connected to $2.8 million in penalties the San Francisco Bay Regional Water Quality Control Board imposed against Sweeney after years of state litigation for his activities on the island. The appeals court hasn’t ruled on the administration’s motion.

The island was sold to John Muir Land Trust, an environmental group that said in January it would restore damage Sweeney caused on the island. The group didn’t respond to a request for comment.

“Point Buckler is one of three islands that form the last points of passage for fish moving to and from the Pacific Ocean, Carquinez Strait, and the Sacramento-San Joaquin River systems,” Linus Eukel, the land trust’s executive director, said in a statement after the purchase. “An opportunity to return to its natural state a place as ecologically important as Point Buckler is rare.”

Sweeney said in an interview he wants the island back, and wants the court to toss out the earlier ruling because he believes Sackett renders much of Point Buckler Island outside the jurisdiction of the Clean Water Act.

“We’ll get the island back, no question,” he said, adding that he’ll try to do so in separate litigation.

“The Ninth Circuit wants this case because it’s a clean case that shows clearly dry land,” he said. “This is the next Sackett case, basically.”

The case is United States v. Sweeney, 9th Cir., No. 25-2498, appeal filed 4/17/25.