A National Academy of Sciences report scheduled for release this week will make recommendations on how hundreds of municipalities in 11 counties can cooperate to halt the sewage pollution that is fouling southwestern Pennsylvania's rivers and streams.

A major component of the report will address how that cooperation could trim millions from the estimated $10 billion cost -- $3 billion in Allegheny County alone -- of repairing aging, broken sewer systems that spill raw sewage every time it rains and threaten the region's public health, environment and image.

"We hope the report serves as guidance on how to address the problems as a region," said John Schombert, executive director of 3 Rivers Wet Weather, a nonprofit group looking for ways to stem the overflows in Allegheny County.

He said the toughest and most expensive problem affecting the region's sewers is the segmented municipal ownership of sewer lines that are part of a larger, regional network. In the 11-county region there are 595 municipal jurisdictions with 492 separate water and sewer providers.

"I hope the report addresses the institutional issues and outlines a framework and process for transferring ownership of sewer lines from municipal to regional management," Schombert said. "It's an institutional arrangement not found in many cities and one that has the largest impact on sewer rates."

Regional cooperation on sewer mapping ---- required in federal consent orders signed by most of the 83 municipalities in the Allegheny County Sanitary Authority's service area ---- has already saved more than $6 million, Schombert said. Doing required municipal sewage flow monitoring on a regional or watershed scale could save municipalities another $10 million. Those sewage monitoring plans must be submitted to Alcosan by June.

Schombert said he hopes the report by the congressionally chartered academy also carries with it federal funds for water and sewer projects.

"Congress has been making changes in the Clean Water Act and decreasing funding despite the increased need for it," Schombert said. "I hope this report will be able to help direct dollars back to the region."

The academy's Committee on Water Quality Improvement for the Pittsburgh Region was formed in early 2002 to study sewage overflows in Allegheny County, and related issues in Armstrong, Beaver, Butler, Clarion, Fayette, Greene, Indiana, Lawrence, Washington and Westmoreland counties.

The total of 755 combined sewer outfalls into rivers and streams in the 11-county region is more than the number found in all but two states.

In Allegheny County alone, an estimated 16 billion gallons of sewage and industrial waste foul waterways with unhealthy pollution each year.

Nancy Barylak, a spokeswoman for Alcosan, which is spending $1 billion to expand and improve its collection and treatment and should finalize its consent order with the U.S. Environmental Protection Agency by summer, said the authority hopes the report will focus on the regional problems and not just Alcosan's.

"Alcosan is only one piece of the puzzle," Barylak said. "It will take a commitment by municipalities up and down the rivers of the region to make a difference."

The recommendations by the academy's National Research Council will address water pollution from failing septic systems and drainage from abandoned mines that contribute to the region's water pollution. The report also will discuss the need for regional water quality standards and address how to educate area residents, who will shoulder much of the cost of improvements through higher sewer bills.

Pittsburgh is not alone in searching for ways to fix its sewer system, a factor that figured heavily in the national academy's decision to undertake the project. There are 1,100 cities, most of them in the Northeast and Great Lakes region, that have combined sewer systems that regularly overflow during rain storms.

Many of those sewer systems, including the one operated by Alcosan, were designed to overflow during storms to prevent damage to treatment facilities. Subsequent changes in federal law have made those overflows illegal.

EPA studies have found that such overflows have damaged the quality of water, resulting in beach closings and fish kills, and have the potential to harm human health. About 90 percent of the water provided by public water suppliers is drawn from the region's rivers and streams.

The almost 300-page report of the 14-member committee chaired by Jerome Gilbert, a nationally known consulting engineer on water supply resources, cost $500,000. It was originally to be done in fall 2003, a schedule that was later amended to late spring 2004. It will be released at 10 a.m. Thursday on the Carnegie Mellon University campus.

F. Michael Langley, chief executive officer of the Allegheny Conference on Community Development, a sponsor of the study, said solving the sewage overflow problem is "expensive and complicated," and will require federal help.

"The National Research Council," he said, "is the only agency with the credibility and experience needed to recommend a new approach to water quality regulation and funding."