Six months after millions of tons of sewage fouled a prime trout stream in Valley Forge National Historical Park, two environmental groups are pursuing legal action against Tredyffrin Township and its municipal authority, saying they violated federal law.

In addition to the March spill, the 30-inch pressurized pipeline ruptured in February and in March 2012, and is likely to rupture again, according to the groups, PennEnvironment and Trout Unlimited, which convened a late-morning news conference at the park's visitor center.

The groups said that they were providing the required 60-day notice of intent to file the suit in federal court, a first step in the process under the Clean Water Act's citizen-suit provision. The groups say they don't want money, but want the "underlying causes" of the spills addressed.

"Valley Creek is widely recognized as the best trout fishery in the world that's located close to a major metropolitan area," said Pete Goodman, a former president of the Valley Forge Trout Unlimited chapter, who said he has fished in the area for 43 years.

In March, to repair the damaged pipes, local pumps were turned off, allowing even more sewage to enter the creek. In all, for more than 30 consecutive hours, several million gallons of sewage were spilled, officials estimated.

In a statement Wednesday, Tredyffrin Township said it was "confused" by the environmental groups' action, adding that "it remains committed to the pursuit of initiatives to reduce and mitigate the effects of future breaks."

Township Manager William F. Martin said in March that "we need to evaluate the whole line," installed in the 1970s.

In addition to Tredyffrin, the line operation is shared with all members of the Valley Creek Trunk Sewer: Easttown, East Whiteland, and Willistown Townships; Malvern Borough; and the Valley Forge Sewer Authority.

While the February and March spills were damaging, Goodman said, the ruptures occurred at "the best time it could have happened." The region had its second-snowiest winter on record, and winter temperatures were well below normal; high water and cold conditions mitigated the spills' impacts.

Owen Owens, cofounder of the Valley Forge chapter of Trout Unlimited and a member of PennEnvironment, said he went fishing soon after the March incident and found that the fish population was largely unaffected.

"We're lucky," Owens said. "We really dodged a bullet."

Owens said that the township had handled breaks well in the past, and now the groups want Tredyffrin and the municipal authority to work up an emergency plan for future leaks.

Heather Govern of the National Environmental Law Center said a future break is "almost guaranteed" if the township does not act now.

She said she hoped a resolution was reached before a suit is filed.

Karl S. Coplan, law professor and codirector of the Environmental Litigation Clinic at Pace University in New York City, suggested that may happen.

Coplan said that when Congress created the Clean Water Act, it wanted full enforcement and thus made it fairly simple for citizens to sue.

"I would say, if they aren't dismissed on some sort of technicality, [these suits] are usually successful, because they're very easy to prove," Coplan said. "They're often settled."

PennEnvironment and the Valley Forge chapter of Trout Unlimited have a meeting scheduled with Tredyffrin on Oct. 13.

"If they come up with something that is binding, there is the potential that we won't need to proceed further," Govern said.

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