The Colorado Department of Public Health and Environment has postponed for two years final rules on water-temperature standards for the state’s rivers and streams.
Saying the science needs to be fine- tuned, department officials are set to adopt interim standards this week and then revisit the issue in two years after more studies.
“The problem is there is some additional science that needs to be done with respect to the cold-water standards,” said Doug Benevento, the department’s director.
Still, the department is forging ahead with a proposal that attempts to regulate temperature for the first time in Colorado’s streams and rivers.
In doing so, the state could join only a handful of states that have tried to protect fish habitat by enforceable regulations, according to the Environmental Protection Agency.
The state has had a number for water temperature on the books since the late 1970s – 20 degrees Celsius (68 degrees Fahrenheit) for cold-water streams and 30 degrees Celsius (86 degrees Fahrenheit) for warm-water streams.
But no one – department officials included – knows how the standard was derived or what it really means.
“It’s fair to say they haven’t been used a lot,” said Dave Moon, with EPA Region 8’s water-quality unit.
The state’s water-quality division has worked on its proposal for more than a year, consulting with industries, environmental groups and cities.
The interests, however, remain divided over the division’s proposal, particularly the proposed cold-water standard.
Several environmental and wildlife groups say the division’s proposal won’t protect several species of cold-water fish and are pushing for a lower number.
“But what we do know is that excess heat is a pollutant that kills fish, and the state’s current standard of 20 degrees (Celsius) is too high,” said Melinda Kassen, director of Trout Unlimited’s Colorado Water Office.
Cities, wastewater treatment plants and others that discharge water into Colorado streams have long resisted a temperature standard, saying that stream temperature is more influenced by drought and stream flow than their activities.
“We don’t want to see a standard adopted if there’s nothing you can do to fix the problem,” said Taylor Hawes, an attorney with the Colorado River Water Conservancy District. “That’s our question: What does the state propose to do?”
Staff writer Kim McGuire can be reached at 303-820-1240 or kmcguire@denverpost.com.
