From The Denver Post (Bruce Finley):

Even with Colorado’s push to rely more on recycled water, the Rocky Mountain Arsenal National Wildlife Refuge will spend another summer using millions of gallons of Denver’s drinking water to fill lakes and irrigate fields after a recent decision by state health officials.

Federal wildlife biologists calculate they’re drawing more than 82 million gallons of Denver drinking water a year to fill three once-toxic lakes at the refuge, formerly a nerve gas and pesticides plant that became an environmental disaster.

“This refuge needs water, and using recycled water to fulfill a portion of our needs is a wise choice for the future,” refuge manager Dave Lucas said. Denver recycled water “meets our needs and allows millions and millions of gallons of drinking water to be put to better use by Denver residents.”

But the Colorado Department of Public Health and Environment last week reaffirmed its position that the refuge must go through a process of proving why it should be allowed to use water that is not as clean and submit to an Environmental Protection Agency review.

A $2.1 billion cleanup of toxic pollution included restoration of the lakes for catch-and-release fishing and to store water, which wildlife managers use to irrigate the 27-square-mile refuge — habitat for bison and other species.

Until the drought of 2002, High Line Canal agricultural water trickled into the lakes. Groundwater pumping added more water. CDPHE at some point — it was not clear when — reclassified the lakes as water supplies, and refuge managers made a deal with Denver to use drinking water, which started in 2008.

Then, in 2009, CDPHE reclassified the lakes as water bodies, meaning “an important social or economic development” reason for allowing lesser-quality water must be demonstrated. State officials, on an emergency basis in May 2013, agreed to remove the water supply classification on the refuge lakes but still require the proof of a public purpose before water quality can be reduced.

Frustrated refuge managers, backed by Denver Water and the Denver Museum of Nature & Science, have been pressing to use recycled water and putting in the plumbing to do so.

Denver Water has spent more than $197 million installing a citywide 80-mile network of pipelines that distribute partially treated recycled water to parks, golf courses and the Denver Zoo. The museum uses recycled water in its new heating and cooling system.

All sides agree that using more recycled water is a priority.

But CDPHE Water Quality Control commissioners on May 13 voted 5-4 to reject a request to reconsider — so the refuge must go through a “necessity of degradation demonstration” review to be able to use recycled water.

“We want to support use of recycled water. But we cannot do it by bending the rules,” CDPHE water quality standards chief Sarah Johnson said. “The best solution is for them to complete the necessity of degradation determination. It isn’t a heavy lift. We have promised to help.”

U.S. Fish and Wildlife Service managers of the refuge say the analysis for the review would not cost much but would require spending $10,000 to $15,000 a year more for water monitoring. They said new analysis would have to be done every three to five years, tied to permitting, creating uncertainty because state officials could ask for operational and infrastructure changes during reviews.

Lucas said even if they were to have something to present by the June commissioners’ meeting, it would be October at the earliest for the water switch if everything was approved.

Denver Water officials have been working aggressively since 2004 to increase use of recycled water, saving 7,000 acre-feet of drinking water a year, utility recycled water director Jenny Murray said.

Switching to recycled water at the refuge is the correct solution, Murray said. “It’s the right use because we are trying to preserve drinking water supplies for a growing population in a water-scarce region. Using drinking water for uses that do not require drinking water is wasteful.”

Denver Water attorneys in a May 6 letter to CDPHE argue that state lawmakers have ordered efforts to “encourage the reuse of reclaimed domestic wastewater.” Denver Water contends CDPHE decisions undermine state policy, waste public resources and defy common sense by imposing a needless bureaucratic burden.

One of Denver’s new recycled water pipelines runs by the Denver Museum of Nature & Science to the refuge. A steady, year-round flow of recycled water in that pipeline is required to ensure sufficient flow to run the museum’s innovative new geothermal heating and cooling system, which was funded by a federal grant to boost energy efficiency.

“When we designed our system three to four years ago, both Denver Water and the refuge folks felt that obtaining a permit to discharge recycled water into the lakes at the refuge would not be a problem,” said Dave Noel, museum vice president for facilities, capital projects and sustainability.

CDPHE’s stance “has got all of us scratching our heads,” Noel said.

Museum officials sent a May 8 letter to CDPHE arguing that “the loss of 17,000 acres of thriving wildlife and fish habitat due to lack of water would be a severe blow to the state and the Front Range, and simply does not make sense when a logical solution seems readily available.”

At the refuge, future water needs are projected as high as 456 million gallons a year. Beyond Denver Water, wildlife managers rely heavily on pumping water from underground aquifers into the Mary, Ladora and Lower Derby lakes — pumping they are trying to reduce by using more recycled water, which is cheaper than drinking water. They calculate the federal water bill could be cut by $30,000 a year.

A thriving bison herd is growing, with 11 calves born this spring, pushing the population to 81. An adult bison can eat around 50 pounds of grass a day. A team of biologists recently had to reduce the herd to prevent exhaustion of the short-grass prairie. Plans call for expanding bison habitat to allow a herd of 209 bison, which would roam up to the road to Denver International Airport, where a visitor viewing station is envisioned. Not having reliable recycled water will limit the bison herd and lead to decreased numbers of waterfowl, fish and grassland birds, Lucas said.

“We’re probably not going to irrigate this summer, which is bad for habitat restoration,” he said, “or we will have to drain down the lakes to irrigate.”

Lucas remains puzzled by the entire process.

“We’re talking about the same recycled water used everywhere. But somehow the refuge is different? Lots of smart people are looking at this, and no one can figure it out,” he said. “We engaged in this year-long process with hopes of fixing their error — the water supply change. Why would we want to engage in another unknown and uncertain process that will last months, if not years?”

More South Platte River Basin coverage here.