Three environmental groups have settled a lawsuit against New Jersey's environmental protection department, clearing the way for the agency to rule on whether a southern New Jersey nuclear plant is doing enough to prevent unnecessary fish kills.

The Delaware Riverkeeper Network, New Jersey Sierra Club and New Jersey Environmental Federation settled their lawsuit Monday against the Department of Environmental Protection, which said it would issue a draft discharge permit to PSE&G's Salem Nuclear Generating Station by June 30.

Salem and Hope Creek nuclear plants (Stan Honda/AFP/Getty Images)

That will force the DEP to take a position on whether the facility's cooling water intake structures must be significantly upgraded to reduce fish kills. The environmental groups say the plant's systems kill more than 3 billion fish a year.

Delaware Riverkeeper Maya van Rossum praised the DEP for agreeing to issue the permit to the plant, located in Lower Alloways Creek Township.

"But their job remains unfinished until it ends Salem's indiscriminate and unchecked fish slaughter," she said. "Salem is having a devastating and lasting impact on the Delaware Estuary's ecosystem. For example, the facility kills 48 percent of the striped bass in the Delaware River every year. Simply put, Salem is the largest predator in the Delaware Estuary and Bay. "

Joe Delmar, a spokesman for PSE&G, said, "We look forward to working with DEP as they consider our permit application."

The environmental groups said PSE&G submitted its renewal application for a New Jersey Pollution Discharge Elimination System permit in February 2006 but NJDEP has yet to make a determination on it.

In October 2013 the three environmental groups sued to force the DEP to take action on PSE&G's application.

Bob Considine, a DEP spokesman, said the agency had been waiting for the U.S. Environmental Protection Agency to issue final national rules that govern permit standards.

"With those rules put in place over the summer, we negotiated a settlement which will see DEP publish a draft permit by June 30, 2015," he said.

In the interim, the plant has been operating with technology that the DEP deemed to be in compliance with federal standards, he said.

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