A continuing contractual dispute between the state Department of Environmental Protection and the University of Massachusetts at Dartmouth is delaying efforts to clean coastal waters all over the Cape and Islands, and must be solved quickly, state Sen. Robert O’Leary said yesterday.

The 11-month standoff has left towns without important data, compiled under the Massachusetts Estuaries Project, documenting the health and particularly the nutrient loading of their estuaries, bays and ponds. The information is needed for remediation and planning.

At the center of the dispute is an issue about who gets to control the flow of data compiled by the researchers on the six-year-old project.

There has been no contract between the state and the Dartmouth School for Marine Science and Technology, which is compiling information for the project, since last July. The parties now are undergoing mediation on their differences, which could produce a result within the next couple of weeks.

In the case of the Vineyard, the dispute has meant a delay of months in producing a final report on the health of the Edgartown Great Pond, the first Island pond to be studied, and also delays in the work on Sengekontacket and Lagoon ponds, which should have been complete or nearly so by now.

The draft report on the Great Pond, provided to the Gazette last November, found water quality was significantly affected by heavy nitrogen loading, and that the biggest single contributor — responsible for one-third of total nitrogen entering the 890-acre pond each year — is household septic systems.

“It’s been such a Mexican standoff,” Mr. O’Leary said.

“If you talk to the university people, and I have, they seem fairly reasonable and they want to resolve it. When you talk to the people at [the Department of Environmental Protection], they have a completely different definition of what the problem is.

“I just don’t get it,” he said. “Meanwhile, the whole process is grinding to a halt. Towns are having difficulty getting the data and getting their projects moving forward. It’s tragic.”

“My understanding is that they have now hired a mediator and are going to resolve it. As I understand it, it’s binding arbitration,” he said.

“Anything to get an agreement. This project underpins what I think is the single biggest environmental threat facing this region, which is nutrient loading in estuaries and bays and ponds. We need the science data to create a framework to decide what we’re going to do.”

And decisions are vital for legal and economic reasons as well as environmental ones, he suggested.

“The data we have so far is demonstrating that most communities in this region are in violation of federal law. They’re in violation of the Clean Water Act,” he said.

“So it’s only a matter of time until someone, some group, takes these towns to court, and says, ‘You’re violating the Clean Water Act and you have to clean it up.’”

“And unlike the rest of the state, it’s not a single system, a single big plant that’s in violation. Who’s in violation here? Hundreds of thousands of home owners who have Title V [septic] systems that are impacting on the water quality, because they don’t deal with nutrification.

“The towns need well over a billion dollars of infrastructure. They have no way of paying for it. If they just impose it on their residents, it will explode their local tax take.

“It’s more expensive if it’s done later and it’s done under threat of a court suit. So it’s a complex issue, it’s a billion-dollar issue,” he said.

Adding to the urgency is the fact that the state is considering a new Clean Water Act, which would help towns address the problem. The bill, if passed, will give towns access to cheap federal and state money.

“It requires the towns to get together a wastewater plan and submit it to the state for approval, dealing with all those nutrient issues, by sewering or other means,” Mr. O’Leary said.

“And if that plan is approved they become eligible to access the state revolving fund at zero interest, and they become eligible to amortize the infrastructure over 50 years rather than 20 years.

“And those two tools can cut in half the betterment charges that they have to impose on residents who hook up to these systems. It changes, dramatically, the financing of this.

“The second thing is it gives the towns authority over these systems that they don’t currently have under state law.

“They can prohibit some home owners from hooking up and they can require others to. It’s called checkerboard zoning. Under current law they can neither require someone to hook up nor prohibit someone from hooking up.”

Mr. O’Leary said the proposed legislation had been reported favorably out of the senate Ways and Means Committee, and would likely come to the Senate floor in a couple of weeks.

“And I’m very happy about that; it’s a major piece of legislation and I’m very optimistic that we’re going to move this on the house side. I’m also meeting with the governor this week.

But the failure of the state Department of Environmental Protection and researchers on the estuaries project to reach agreement over their contractual issues is impeding it all.

“All of that political and financial framework is based on these studies,” he said. “This is not just a study, it’s the foundation for a major policy initiative for the whole southeastern part of Massachusetts and it’s got to happen.

“I want to see it resolved,” he said.

In the meantime, though, steps are being taken on the Vineyard in anticipation of the project’s eventual findings.

Edgartown wastewater superintendent Joseph Alosso said 119 homes in the Edgartown Meadows subdivision have already been approved to tie into the town sewer. Next would be 149 homes at Island Grove. And a sewer line being run from the new Field Club development at Katama to the Edgartown wastewater treatment plant would allow another 300 to 350 homes to tie in.

Mr. Alosso said collectively the tie-ins would exceed the reduction called for in the draft report.

The town had moved in advance of the final report from the project, he said, because “we kind of knew what was coming.”

For the same reason, he said, Edgartown and Oak Bluffs are arranging their own study of Sengekontacket Pond.