Wetlands account for less than 2% of the landscape in Colorado but provide critical habitat for nearly all wildlife species. Rehabilitation of an existing wetland complex in southwest Colorado by Colorado Parks and Wildlife will restore important habitat for waterfowl, waterbirds and other wildlife in the area.
For the past four years, along the Dolores River in the Lone Dome State Wildlife Area, Wildlife Technician Ryan Lane has reconstructed a series of levees that allow water to accumulate and drain. He put them to work in mid-May when water flowed via a ditch from the Dolores River into shallow impoundments. Located about five miles downstream of McPhee Reservoir, the levee structures will help replicate the natural process of over-bank flooding now absent due to the presence of the dam.
When the Dolores Project, which created McPhe Reservoir, was authorized and constructed, the U.S Bureau of Reclamation acquired the properties that now comprise the Lone Dome State Wildlife Area and conveyed them to CPW as mitigation. CPW actively manages the property for the benefit and protection of wildlife. CPW added wildlife uses to its senior water rights decree on the Lone Dome Ditch to facilitate irrigation of more than 100 acres of wetland habitat.
“These are not ponds, these are what we call ‘shallow-water impoundments’,” Lane explained. “The key to a good wetland is that it gets covered with water and then the water drains away. Then plants grow on the wet ground which provide forage for waterfowl and other wildlife.”
Historically, this valley of the Dolores River functioned as an active floodplain that supported a diversity of wetland and riparian habitats. During the spring run-off the river would overflow its banks, flood low-lying areas and the water would make its way back to the river, either on the surface or as shallow groundwater. A wide variety of plants would flourish in the moist soil left behind. But because the flow of the river is now controlled by the dam, flooding events no longer occur. Lane, who worked for more than 20 years on the South Platte River in eastern Colorado, learned how wetlands worked and how to build them effectively.
“We have bodies of water in southwest Colorado, but we don’t have a lot of true wetlands. Just building a pond doesn’t make a wetland,” Lane explained. “We’re not trying to store water.”
Shallow ponds were built in the same area years ago to provide waterfowl habitat, but were not constructed for water to flow through. Eventually, they became choked with vegetation and were difficult to manage for the benefit of wildlife. CPW’s understanding of managing wetlands has evolved to understand that constructed wetlands require active management of plants and water to provide the best results. Management activities include flooding, draw-down of water, mowing, mulching, tilling and weed control.
Using heavy equipment, that often wasn’t heavy enough, Lane pushed cattails out of areas that total about 80-acres. Then he built eight levees, each fitted with irrigation drains that control how much water flows in and out. In early May, he filled the area with water from the Lone Dome Ditch so the ground and levees would become saturated. Water was held in the impoundments for about a week before Lane drained them and let the water flow back to the river. This will encourage recruitment of native wetland species.
The area will dry through the summer; then in early fall, he’ll run water again and hold it until November to saturate the area one more time. Next spring, Lane will plant millet and native wetland seeds in the impoundments, putting in just enough water to stimulate growth. The water levels will be managed so that the seed heads of the plants are just above the water − but the water will not be so deep that it could drown the plants. A similar management regimen will continue year after year to imitate the natural systems present before the dam was built.
“Those seed heads are the best forage. We’re not in a fly-way, but this will really attract waterfowl. It will imprint on them to return again and again, especially in the fall when they’re migrating,” Lane said. “This will be a great area for duck hunting.”
But waterfowl won’t be the only critters to benefit. These wetlands – like wetlands anywhere – will attract all variety of wildlife, including bears, deer, elk, small mammals, birds and insects.
A day after water flowed behind the levees, a smattering of ducks could be seen swimming and diving.
As he looked over the water at the ducks, Lane said: “Wetlands are kind of like what was said in that movie, ‘Field of Dreams.’ Build it and they will come.”
Joe Lewandowski is the public information officer for CPW’s Southwest Region. Joe is based in Durango.