Ambassadors of several environmental groups presented a letter to Durango City Council on Tuesday evening urging the city take action to mitigate the impact that Lightner Creek is having on water quality in the Animas River.

The primary cause for concern, letter signatories said, is sediment carried by the creek from Perins Canyon and near the Tech Center into the Animas River. They also highlighted the adverse impact of biohazards dumped into the waterway by the Lightner Creek Mobile Home Park.

Nine private residential property owners signed the letter in addition to an assortment of fly fishing outfitters, whitewater guides and environmental groups, including San Juan Citizens Alliance, Trout Unlimited and American Rivers.

“We are deeply concerned about the unmitigated sediment entering the Animas River from Lightner Creek and the impact to the fishery and properties down river,” Ty Churchwell, mining coordinator with Trout Unlimited’s national organization, told the council.

The five speakers at Tuesday’s meeting expressed concerns over how declining water quality could impact outdoor recreation and Durango’s tourism economy.

“It’s bad for business, it’s bad for Durango, it’s bad for all of us,” warned Tom Knopick, co-owner and founder of Duranglers Flies & Supplies.

Although heavy metal loading from historic upstream mining activity has imperiled water quality in the Animas River for over a century, cleanup efforts have proven successful in recent decades. In 1996, Colorado Parks and Wildlife deemed a 4-mile section of the Animas, beginning at the confluence with Lightner Creek, a Gold Metal Fishery.

“Sediment from Lightner Creek is doing more harm to the Animas south of town than metals,” Churchwell told councilors.

Sediment inhibits the ability of fish to search for food by clouding the water, said SJCA Animas Riverkeeper Sara Burch. Cloudy discharges from Lightner Creek also inhibit the growth of macroinvertebrates – the small living creatures upon which trout feed – and absorb sunlight, raising water temperatures to levels that cannot sustain fish life.

The letter cites a 2010 study conducted by Basin Hydrology which found that small particles of clay and silt are easily picked up in Perins Canyon and moved by the creek, often remaining suspended for long periods of time. Water flowing off the Hog’s Back area through the Tech Center stormwater retention system and from Perins Canyon was found to have “extreme” sediment loads.

The retention pond intended to settle some of the sediment flowing through the Tech Center system is “poorly inadequate,” Churchwell said.

“This is a sediment problem,” warned Buck Skillen, a past president of the Five Rivers chapter of TU. “It starts on both county and private land in the county, and then becomes a city of Durango problem in the form of stormwater management.”

Churchwell said that although the sediment loading from Lightner Creek has been on the radar of those paying attention to water quality since at least 2009, the situation has deteriorated in recent years. Monsoon rains are direly needed in the southwest, but the growing unpredictability of their arrival and intensity is a problem for fish.

“Last summer, basically the river was unfishable ... because every time it rained ... over the tech center area or over that Lightner Creek area, it would run dirty for two three days after,” Churchwell said in an interview with The Durango Herald.

He described to City Council the “torrent of dark, muddy water” that Lightner Creek injected into the Animas River when it rained.

With respect to mitigation, the solutions are not entirely clear.

A larger retention pond for settling or some engineered wetlands were among the possible solutions that Churchwell floated, although he stressed he is not an engineer.

Burch said that solutions could involve both upstream work to limit the amount of sediment that enters Lightner Creek in the first place, as well as more downstream work to filter out sediment before the creek enters the Animas.

Churchwell emphasized that the letter is not intended to antagonize the council, but to start a conversation about potential solutions. He and his co-signatories intend to bring the letter to La Plata County soon.

“We want to partner with you to resolve the problem,” Churchwell told councilors in conclusion.

rschafir@durangoherald.com