On a day when 755 sewer overflows spewed raw sewage into the region's rain-swollen rivers and streams, the National Academies of Science released a study that says cooperation on planning and operating sewerage systems is necessary to stem the pollution.

The study, released yesterday at Carnegie Mellon University in Oakland, strongly recommends that management of the fragmented, municipally owned sewer systems in and around Pittsburgh be consolidated either through merger of city and county governments or the establishment of regional management organizations.

According to the study, surface water in southwestern Pennsylvania is degraded for recreation, aquatic habitat and fish consumption and that a regional approach is necessary to assess the problems and construct and maintain sewer improvements in the most cost-effective way possible.

"The region's waters have long been an important asset," said Jerome Gilbert, chairman of the committee that wrote the report and a nationally known consulting engineer on water quality. "But for the area to reach its full potential in terms of recreational use of the rivers and riverbank development, it is important to clean up the waters further and meet standards for water quality."

Federally mandated improvements to the sewer and septic systems that dump raw sewage into the region's rivers and streams every time it rains could cost as much as $10 billion, but cooperative study, planning and purchasing could melt millions from that outlay.

There are 595 municipalities and 492 water and sewerage providers in the 11-county region.

The report says meeting the costs of sewer system improvements will be difficult for local municipalities given the economic climate of the region and the reduced levels of federal and state funding available. Sewage bills in southwestern Pennsylvania are already higher than the national average.

Gilbert said the study committee was aware of the political difficulties inherent in a cooperative approach.

"The preference for local government reflects local social interests, but this is a problem that is regional in scope and cost," he said. Although there are no estimates of the economic benefits that would flow from addressing the water quality problems, the report says the region could expect to benefit from measures that "significantly reduce drinking water risks and enhance recreational opportunities."

The study also found that acid mine drainage and agricultural runoff are significant contributors to the water quality problems, and that many of the region's tributary streams do not meet clean water standards even in dry weather, suggesting chronic sewage contamination from failed septic systems and broken sewer lines.

The study mirrors the findings of a 2002 study, "Investing in Clean Water," put out by a local steering committee chaired by Carnegie Mellon President Jared Cohon, that recommended prioritizing capital investments and municipal cooperation.

"This study strongly confirms the importance of a regional approach, but going from this point forward is not going to be easy," said Cohon, who is an environmental systems engineer. "But if we can meet the challenge, we can not only improve the quality of our lives but be a national model."

There are 1,100 urban areas, most of them in the Northeast and Great Lakes region, that have combined sewer systems that overflow every time it rains. And the U.S. Environmental Protection Agency has cracked down on Atlanta, Seattle, Baltimore, Boston, Chicago, New York, Philadelphia and Erie, requiring them to clean up their sewage overflows.

The 300-page study of the 14-member committee, found that: The most pressing water quality problem with the potential to cause human health problems is microbial contamination from improperly managed sewage. Water quality data for the region?s rivers and streams is so inadequate that it prevented the committee from assessing the full extent of sewage pollution. Additional study is recommended, but many of the entities that have done testing in the past no longer do that work. Best management practices for septic systems should be implemented throughout the region. A sewer and water user surcharge should be established to fund the first few years of planning and data gathering. Such data gathering is critical to identifying the amounts and impacts of various pollution sources entering the region?s surface and ground water, the report said. The Allegheny County Sanitary Authority should reevaluate its 1999 long-term plan for controlling combined sewer overflows to reflect ongoing federal consent order negotiations. Nancy Barylak, Alcosan spokeswoman, said the study recommendations are welcome and will be reviewed. She said they would not delay ongoing improvements to the authority?s collection and treatment systems.