About a year ago, Philadelphia resident Kelly O'Day took a tour of the Tacony Creek Park.

He'd been a resident of Philadelphia most of his life, but he'd never been there. He thought it would be a beautiful nature spot.

Instead, the retired environmental engineer, who spent much of his career in the business of water supply and wastewater, was appalled at all the trash he saw in the creek.

The trees were draped with plastic bags. Cups and cans were awash in the shallows.

"To me, it could be almost as nice as the Wissahickon," he said. "But it was grossly overpolluted. I've been in pollution control … That creek has not made a lot of progress."

So he decided to document the problem.

Ever since, he's been walking along the creek, photographing the mess and trying to figure out how it happens.

"I've got the skills and the background and the interest," he said. "I'm bound and determined to see what we can do to clean up the creek and its tributaries."

He's been issuing a series of reports that he emails, and the latest one went out last week summarizing the sources and extent of the trash going into the Tookany-Tacony-Frankford Creek, which he affectionately just calls "the Tacony."

He realized one of the major sources of trash to the creek was street litter that flows into the Philadelphia Water Department storm sewer system and is discharged to the creek through an outfall.

The storm sewers are designed to collect trash before it goes into the system, and the department regularly cleans out the inlets.

But O'Day set up an aquarium to simulate a storm. He added plastic bags and some dirt and churned it up. The bags stayed suspended in the water … good candidates for washing into the creek instead of getting trapped in the stormwater inlet.

Philadelphia is poised to take on the issue of plastic bags this fall, in all likelihood. Industry has championed the idea of a more vigorous plastic bag recycling program. Others have proposed instituting a plastic bag fee. Or an all-out plastic bag ban.

O'Day says he doesn't want to express an opinion on any of that. He just wants the public to be aware of the problem.

"There is a major link between street litter and Tacony Creek plastic bags," he said. "It's not just an aesthetics problem. It really is a pollution problem."

You can see photos and read more about it on his blog.