Four conservation groups have filed suit accusing the Environmental Protection Agency of failing to address pollution from agricultural runoff afflicting the Shenandoah River. The groups contend that the EPA is letting Virginia’s Department of Environmental Quality classify the river as “unimpaired,” which they say is a violation of the Clean Water Act.

In a complaint filed May 30 in U.S. District Court for the District of Columbia, the groups allege that runoff from livestock and poultry operations “has caused algae blooms so severe they have been linked to major fish die-offs, severe decline of underwater aquatic plants, and conditions so unsightly and odorous that some visitors have turned away rather than use the Shenandoah River for swimming, boating, and fishing.”

The lawsuit was brought by Earthjustice, a nonprofit environmental law organization, on behalf of the Shenandoah Riverkeeper, the Potomac Riverkeeper, the Potomac River Smallmouth Club and the Warren County, VA, chapter of the Izaak Walton League of America.

The Shenandoah Riverkeeper and others have for several years complained that the DEQ is permitting farmers to overapply cattle and other animal manure to crop fields, which then washes into the nearest waterbody when it rains. The nitrogen and phosphorus in the runoff trigger enormous blooms of slimy green algae in the river and depletes oxygen in the water that fish and other aquatic animals need to live.

The EPA has said the state’s clean water standards were too challenging to apply to the Shenandoah’s problems, a stance the lawsuit deems to be “arbitrary and unlawful.”

“EPA has absolutely abdicated its duty by throwing up its hands in the face of a criterion that is supposedly too ‘challenging,’” said Jennifer Chavez, Earthjustice’s lead attorney on the case. The Shenandoah Riverkeeper has provided material evidence of “objectively verifiable impairment since at least 2010,” she said, “and DEQ has made the same excuses in each biennial impairment listing process.”

The groups’ lawsuit argues that the EPA neglected its duty under the Clean Water Act when it failed to declare the Shenandoah impaired by excessive algae, and then failed to develop a “total maximum daily load,” or pollution diet, for the nutrient pollution causing the blooms.

David Sternberg, spokesman for EPA’s Region 3 office, which includes Virginia, said he was not at liberty to discuss details of pending litigation. But DEQ spokesman Bill Hayden said that “to date, DEQ has not found sufficient evidence that there is an impairment due to algae.”

In April, the Environmental Integrity Project, a Washington, DC-based watchdog group, issued a report saying that almost half (seven of 16) of the long-term state monitoring stations on the Shenandoah and its tributaries have detected high phosphorus pollution levels from 2014 through 2016.

“The public relies on EPA to be the backstop when states fail to protect our waterways, but in this case both EPA and Virginia have ignored the overwhelming evidence of algae pollution in the Shenandoah,” said Phillip Musegaas, vice president of programs and litigation with the Potomac Riverkeeper Network, which includes the Shenandoah and Potomac riverkeepers. “We took legal action after years of trying to solve this problem collaboratively and making little to no progress. Our goal is a clean, safe, fishable, swimmable Shenandoah for everyone to enjoy.”

Herschel Finch, conservation chairman for the Warren County Izaak Walton chapter, voiced his frustration with “seven years of their trying to get DEQ to list the Shenandoah as impaired.”

Finch said the Shenandoah is “near and dear” to people in Warren County, who, like other areas of the Shenandoah Valley, value the region’s multimillion-dollar outdoors industry. He called the lawsuit the “next step” necessary to address a continuing problem, saying the league and its partners had “done everything we can do” to get DEQ to address the river’s algae blooms.

“The Shenandoah is one of the most beautiful rivers in the country, and a popular recreation destination,” said Mark Frondorf, Shenandoah Riverkeeper. “But it’s threatened by the failure of state and federal authorities to stop excessive nutrients, and the algae they produce, from entering the river. We hope this lawsuit will change that.”