Time and again, big rains or small, the many creeks of Western Pennsylvania flood. The reasons are many, say local water experts who point the finger of blame mainly at over-development and poor maintenance of streams and creeks.

		Graphic: Etna flooding

Sometimes, though, even creeks that have undergone improvement continue to flood, said Werner Loehlein, the chief of water management with the U.S. Army Corps of Engineers' Pittsburgh District Office.

On the Little Pine Creek in Etna, a record-level flood in 1986 killed six people and caused $2 million in damage. That catastrophe led to millions of dollars in grant money to improve the creek, including dredging it and fortifying its banks.

Two bridges that crossed the creek in Shaler were raised so debris would not back up behind them, and another was removed, said Tim Rogers, the township manager. Officials recommended raising three other bridges in Etna, including one that had a tractor trailer stuck under it in 1986, but that work was never done.

Containment ponds that had been suggested along the creek were never completed, said Tom Donatelli, director of public works for Allegheny County.

Etna was among the hardest-hit areas in the region after yesterday's downpour.

"This one was very simply an excessive amount of rain," Rogers said yesterday. "It just rains too much."

Even if every improvement can't be made, some work is better than none, Loehlein said.

"If you didn't do what you did, it would have been worse," he said. "You can't control it 100 percent. You do the best you can."

One way to ease future problems is for local municipal officials to take greater care in where they allow new construction, said Fred Baldassare, a hydrogeologist with the state Department of Environmental Protection.

"That doesn't mean we keep development away completely," Baldassare said. "We just need to be more careful."

With miles and miles of concrete and asphalt roads and parking lots, rainwater has nowhere to drain. Instead of seeping naturally into the ground, the water runs quickly into streams, causing overflow, and taking with it pollutants like fertilizer and oil picked up along the way.

"The term sprawl is used a lot, and that's one of the impacts of sprawl," said Baldassare. "We keep adding more impervious surfaces with roadways and driveways."

He used Monroeville as an example of the impact development can have on flooding. The buildup of that area's shopping district, with its huge buildings and equally large parking lots, led several years ago to heavy flooding in Pitcairn.

"Look at all that pavement and how quickly [runoff] gets to the downstream section," Baldassare said.

But there are ways to reduce the impact of development, he continued.

Simple islands with grass, trees and other landscaping in large parking lots can help ease the runoff to local creeks.

Or, contractors can build detention ponds to collect water from parking lots, which was the case at the Ross Park Mall.

There are other ways, both structural and not, to reduce the incidence of creeks flooding, said Loehlein.

Streams can be deepened -- which typically removes the sediment that's been deposited at the bottom over many years -- or engineers can reduce the number of, or severity, of the bends in the waterway.

He cited a channel-improvement project in Johnstown as an example of one that's been successful. The downtown area used to flood twice a year, but after the work was completed on the Little Conemaugh River and Stony Creek, flooding there has been almost completely eliminated.