DURANGO, Colo. – Rain is badly needed in the southwest corner of the state and Colorado Parks and Wildlife aquatic biologists are hoping that predictions of a strong monsoon season come to pass. But even with rain, the extremely dry conditions will affect aquatic resources and riparian areas this summer.
How the dry conditions will affect resources over the long-term is impossible to say, but the lack of water is already causing some current problems for the agency’s aquatic and water managers.
With snowpack conditions in the Southwest Region ranging from only about 10 percent of average, the spring run-off is noticeably low and in some rivers has already peaked.
The dry conditions are causing problems at the Durango fish hatchery which draws its water from a nearby spring. A lack of rain last summer and the low winter snowpack have prevented the spring from recharging. The spring has been delivering less than half the usual amount of water for this time of year, said Toby Mourning, Durango hatchery manager. That means there’s less water in the hatchery raceways where fish are placed to grow to stocking size. Consequently, the CPW has started stocking fish a couple of months earlier than usual.
“Many of the waters that are usually still snowed in at this time of year are open, so we can get to stocking locations,” Mourning said. “And the good news for anglers is that some fishing areas that are typically inaccessible this year are open.”
Hatcheries in other areas of the state are not facing severe problems, but managers are wary about conditions that could change quickly, said Matt Nicholl, CPW’s hatchery chief. Snowpack in central and northern Colorado is well above 50 percent, so most other hatcheries have enough water, at least for now.
“But we’ll be keeping a close eye on the situation,” Nicholl said. “We are anticipating that we could have problems all over the state.”
Spring and summer monsoon rains ‒ if they arrive ‒ will certainly help rivers and streams. But the overall lack of adequate runoff will shrink available habitat for fish and other aquatic life, said John Alves, senior aquatic biologist for CPW’s Southwest Region. Some smaller creeks have already dried up and it’s likely that many young fish that hatched last fall or this spring will not survive.
As the summer wears on, water temperatures in streams and reservoirs will probably increase. Trout struggle to survive when water temperatures rise to 70 degrees because less oxygen is available, Alves explained. Warm temperature and low water levels can also lead to algae blooms in rivers and reservoirs which cause oxygen levels to drop when algae die and decompose.
Anglers are asked to carefully consider the water and weather conditions when they go fishing. If a stream or river seems too warm or appears to be very depleted, it would be best to leave the fish undisturbed. During mid-summer, try to fish early in the morning when the water is coolest.
Fire is a serious concern for native cutthroat trout populations that inhabit small streams in the mountains. Rainstorms after fires can wash ash and silt into streams and choke fish. In previous years CPW staff has gone into critical areas after fires, removed native fish and moved them to hatcheries or other waters.
In the San Luis Valley, Tony Aloia, CPW’s water technician, will have his hands full coordinating water distribution throughout the summer. CPW owns several water rights in the valley and operates a major reservoir high in Rio Grande County. Aloia works with ditch companies, reservoir operators and ranchers to keep water flowing for the benefit of wildlife and agriculture.
“We have agreements with irrigators and we all work together to honor our obligations,” Aloia said.
But Aloia is also concerned about riparian habitat ‒ those areas along river corridors.
“Drought doesn’t only affect fish. The vegetation along rivers and creeks is very important for a variety of wildlife and it provides thermal cover for the water,” he said. “During the last major drought in 2002 we had big die-offs of cottonwood trees along the Rio Grande and other rivers. Those trees come back but it takes a long time.”
Patt Dorsey, regional manager for CPW’s Southwest Region, said this will be a challenging summer.
“In a dry state like Colorado, we should always be thinking about using water wisely,” Dorsey said. “This year, that is an imperative. CPW will be working with our partners throughout the region to maintain
water and aquatic resources. And we may ask for help from anglers and the general public
as summer progresses.”