YAKIMA — The largest and longest-running water rights court case in the state of Washington has come to an end.

Yakima County Superior Court Judge F. James Gavin signed a final decree Thursday morning in the Acquavella case at the Yakima County Courthouse. The decree confirms all surface water rights for the Yakima Basin and its tributaries, ending almost 42 years of litigation.

About 50 people attended the hearing, standing to applaud when the signed document was handed to the court clerk. Gavin described it as a special occasion many thought would never come.

“Although it has taken a long time, it really was necessary,” he said. “It was a truly complex case and required a lot of work by a lot of people.”

Ecology v. James Acquavella, et al. was filed in 1977. Acquavella sought assurances that he would have water to irrigate 5 acres and was the first person listed in state Department of Ecology’s petition for adjudication.

Elements of the case went to the state Supreme Court four times.

Maia Bellon, director of the state Department of Ecology and a water attorney, said the case settles nearly 4,000 water claims resulting in nearly 2,500 water certificates covering the 6,150 square-mile Yakima basin, about 10 percent of the state’s drainage area for surface waters.

She said it may be the longest-running court case in the state’s history. It provides certainty and priority of use, something that’s critical in water-short years. The Yakima basin has been through seven declared droughts since the case started.

“There have been some hard-fought skirmishes right here in this very courtroom on water day, and plenty of disagreements,” she said. “We have had decades to build trust in this courtroom, trust that’s led to a shift in the paradigm that’s led to phenomenal change in how we approach water management no longer as adversaries, but truly as partners.”

The audience was filled with people representing local, state and federal governments, the Yakama Nation, irrigators and court staff. Gavin recognized many of the key players, and gave audience members a chance to share stories and memories. Many attorneys mentioned colleagues from whom they “inherited” the case.

Yakima attorney Sidney Ottem began working on Acquavella out of law school in 1993. He later served as a court commissioner, overseeing water-day hearings and making decisions. The case involved many “first impressions,” or issues that hadn’t been previously decided. It also changed how people approach problem solving when it comes to water in the basin, he said.

“The thing that sticks with me the most are the stories that get to be the archive of water use in the Yakima Basin,” he said. “I never got tired of listening to any 80- or 90-year-old guy coming in to talk about the water use on the property when he was a kid.”

Tina-Marie Lasha, daughter of the late Judge Walter Stauffacher — who oversaw Acquavella for 29 years — said her father was born and raised in the Yakima Valley and the case was his life’s passion. He occasionally would wear a Mickey Mouse tie to court to signal to attorneys that he “wouldn’t stand for any antics” and, if necessary, would wear the tie on top of his robe.

There would be days “he came home and said, ‘Everybody in water court was mad at me today and that was a good thing,’” she said. “’Not everybody got what they wanted, but they all got what was fair.’

“And his entire focus was to be as fair as possible to everyone.”

Gavin said his predecessor’s legacy was twofold: the water adjudication and a change in the state Constitution. Stauffacher secured a constitutional amendment so that he could remain as a judge pro tem on the case after he retired, something that wasn’t allowed at the time. Gavin said he, too, has benefited from that change.

“The Stauffacher amendment I think is wonderful and is part of his legacy,” Gavin said.

Lasha said the change allowed her father to care for her mother at home and stick with the case.

Gavin thanked the attorneys for being fully prepared, and for their professional manner. Arguments were always on point and well presented, he said, even during highly and hotly contested issues.

He said some might refer to the final decree as the “finally, decree.”

The Department of Ecology is planning a celebration recognizing the end of the Acquavella case on June 5 at the Yakima Greenway.