TINA MARKOE/Courier-Post Lew and Diane Stout paddle their canoes.

More than 40 percent of the flow in the Cooper River was wastewater before the first phase of the system went on line. Afterward, that flow had been replaced by rising ground water and rain water. And within two years of the entire system being in operation, 99 percent of the bacteria in the river was eliminated.

Dampening the comeback, however, is that the same fish prized by anglers, including striped bass and perch, tend to accumulate toxins from pollution in their tissue. Another problem going back to the 19th century makes it technically unsafe to swim in the industrialized stretch of the river, although the water is considered safe for water skiing and jet skiing.

Camden, Gloucester and Philadelphia have many miles of antiquated sewer mains that allow storm water to mix with raw sewage. Newer communities have separate system for storm water and sewage. When the older urban systems become overloaded during heavy rains, valves known as combined sewer overflows open up to relieve the pressure. The system was designed to protect sewage treatment plants, but the mix carries harmful bacteria and pathogens into the river after heavy rains.

Fixing this problem will be expensive. In 1991, the CCMUA paid $1.1 million to repair 30 of 38 sewer overflows...actually big metal gates...that were broken or stuck open, a situation that allowed raw sewage to flow into the river even in dry weather.

Now the cities of Camden and Gloucester, as well as the CCMUA, are considering installing nets or metal screens at each of the overflow valves...including one near the mouth of Newton Creek...to capture feces and trash before they get into the river. This could cost $10 million to $20 million.

But harmful microbes will still flow through these devices, meaning the cities may have to add disinfection stations or even build small treatment plants at each of the overflow valves, CCMUA Deputy Director Andrew Kricun says.

He estimated the cost of disinfection systems could be $20 million, while construction of individual treatment plants could easily exceed $100 million...costs the cities who own the systems would have to pass on to ratepayers.

Lew Stout, who spends canoe trips picking up trash floating in the creek, feels these alternatives may be impractical.

He says the treatment plant should be expanded to handle storm water from Gloucester and Camden...another costly option.

But whatever route is ultimately taken, he says the cleanup has been well worth the costs.

"Just consider the alternative," he says.

Read also: An early focus of pollution cleanup