Along the Delaware River, flooding is getting worse; new contaminants are showing up, and brook trout - the state fish of both Pennsylvania and New Jersey - have all but disappeared from its tributaries.

On the land, one football field's worth of forest disappears every two hours. With the population nearly doubling over the last century and still growing, landscapes are becoming developed at a pace of 25 to 35 acres a day.

At the same time, once-scarce bald eagles soar overhead and striped bass have recovered. Half a century ago, dissolved oxygen levels in the river at the Ben Franklin Bridge were zero. Now, they meet national standards.

Overall, the improvements constitute "a sensational national environmental success story," said University of Delaware water resource specialist Gerald J. Kauffman.

A report being released today, several years in the making, documents this bouillabaisse of plusses and minuses for the Delaware River Basin, a 13,000-square-mile chunk of the continent stretching from the Catskills to Cape Henlopen.

In 86 pages of trends and data, it attempts to quantify all that the river basin is - and is not.

The Delaware River Basin Commission, an interstate and federal agency that produced the report with dozens of scientists from government and universities, is aiming for the report to serve as a benchmark against which future gains or declines can be measured.

Coupled with a similar one, smaller in geographic scale, released last summer by the Partnership for the Delaware Estuary, they can become tools for moving ahead, said Robert Tudor, deputy director of the DRBC.

None too soon, perhaps.

Just around the bend is climate change; its effects are already being measured in the basin, and it could ultimately transform virtually all of the 36 "indicators" that the report attempts to measure.

Rising sea levels could swamp low-lying areas and engulf bridges, industries and wastewater discharges. Salinity increases could threaten drinking water supplies.

More frequent droughts could cause water shortages; heavier rainfalls could exacerbate flooding.

"We are already in a changing landscape," said Danielle Kreeger, science director of the nonprofit Partnership. "It's climate change on top of change."

One of her concerns is the estuary's signature tidal marshes, which would be killed by increasing salinity.

"They are the fish factories. They are the kidneys for water quality," she said.

Scientists who worked on both reports will be meeting today at the John Heinz National Wildlife Refuge at Tinicum to further develop metrics and ways to gather apples-to-apples data.

For Tudor, one of the most alarming aspects the report revealed was flooding, which has resulted in $473 milion in insurance reimbursements since the late 1970s. The number of "repetitive loss properties" was 317 before 2004. The major floods of 2004, 2005 and 2006 resulted in 1,949 properties being added to the list.

Tudor sees water quality as one of the basin's successes.

The waterfronts of Philadelphia and Camden have gone from dumping grounds to destinations. "Instead of being the back yard, it's the front yard," he said. "It's due to a lot of regulation, a lot of management over a period of decades."

Yet significant problems remain. While scientists are tracking new water contaminants from pharmaceuticals and personal care products, they must deal with legacy pollutants such as polychlorinated biphenyls or PCBs; even though their use was banned in the 1970s, they are still ubiquitous.

At various locations throughout the basin, health officials warn against eating contaminated fish. American eel and carp from the main Delaware, for example, should not be eaten at all.

Delaware Riverkeeper Maya van Rossum lauded the reports for their role in highlighting "the delicate fabric of the Delaware River" and the fact that "it is critical to supporting every element of our communities."

It serves many masters, from the 15 million people who depend on it for drinking water to the shippers who use it to transport 40 million gallons of crude oil a day.

But she was dismayed that so many of the recommendations in both documents simply called for further study rather than immediate action.

With so many participants, she said, the process led to "the lowest common denominator rather than the best aspirations. . . . They lost the power of the moment, working so hard not to offend."

But Jennifer Adkins, executive director of the partnership, said the strength of both reports lay in the fact that the process was so inclusive.

"That's the unique role we play," she said of the partnership. "It's important to be able to bring different people to the table."

Contact staff writer Sandy Bauers at 215-854-5147 or sbauers@phillynews.com.