Fargo and Moorhead made it through another spring without a major flood — and without settling the region's ongoing dispute over flood control.

The $2.1 billion Fargo-Moorhead Diversion Project is one of the most massive public works projects on the federal government's drawing board. It's also a project that has been bogged down by years of legal challenges and bad blood. The fight pits communities the project would protect against those that would end up on the wrong side of the dams and retention walls built to safeguard Fargo.

Last week, the Eighth U.S. Circuit Court of Appeals upheld a ban on the construction of one of those flood control structures — a ring dike around the small North Dakota towns of Oxbow, Hickson and Bakke — until the Minnesota Department of Natural Resources decides whether it will allow engineers to build a flood control dam across the Red River of the North.

The dam, paired with a 36-mile channel around Fargo, would push water away from the city and onto lands south of Fargo. The proposed ring dike would protect Oxbow and its neighbors from diverted floodwater.

But Minnesota officials, and diversion opponents who filed suit against the project, argue that the ring dike — which would protect the towns from floodwater backing up from the dam — should not be built until the dam is approved.

Opponents cheered the ruling — the latest in a long line of court and administrative challenges to the project.

"Fargo Diversion Authority [supporters] have argued 12 ways til Sunday that Minnesota has nothing to say about this project, that this is a federal project," said Fargo-area attorney Cash Aaland, a longtime opponent of the diversion project in its current form.

"This is affirmation," Aaland added, "that the Minnesota DNR [and] their decision has to be respected."

Supporters say the project must go forward. The Red River of the North has flooded 49 of the past 112 years.

Although Fargo has been spared a major flood in recent years, the north-flowing Red River is prone to spring floods, as meltwater from the south hits ice jams and spills onto the prairie, forcing the community to turn out in force to sandbag as the water spreads for miles.

"It doesn't change anything," Darrell Vanyo, chairman of the Fargo-Moorhead Flood Diversion Authority, said of the appeals court ruling. But it does, he said, inconvenience residents in Oxbow, who are trying to make plans for the future.

While both sides agree that Fargo needs protection from floods, the sheer size of the diversion and the impact it would have on communities and farmers upstream has divided the region. In late May, a Minnesota watershed district walked away from the diversion authority board.

The Minnesota DNR released a detailed environmental review of the diversion project last month highlighting "serious concerns" about the project's effect on the environment, water quality and population of the region. If the project goes ahead, DNR Commissioner Tom Landwehr said, 2,000 acres in Minnesota would be flooded, while thousands of acres in North Dakota, including existing flood plains, would be high and dry.

"The question that fundamentally has to be answered is, 'Is the project a reasonable approach to address the flood risk to the area, or are there other possible ways to provide flood protection with less impact?' " Landwehr said at the time of the study's release. "We still think there are still some serious, unanswered questions."