Submitted by Butch Clark

“Sometimes we don’t know what we have until it is gone.” This heading on a brochure captures the motivation for a planning project underway in Chatfield Basin. This planning project is about how to connect and protect natural values in the remaining wide open space, riparian corridors, and stream within and around South Platte Park. Ray Sperger, Resource Specialist with the South Suburban Park and Recreation District, described the need to provide for wildlife and non-motorized access across U.S. Highway 85 between Colorado Highway C-470 and Castle Rock. With the help of Great Outdoors Colorado grants, the generosity of many land owners, and financial and in-kind support from a great many partners, the Chatfield Basin has become a network of very special places. Linking them by “user” friendly corridors is essential.
Because of its beautiful scenery, trails, and proximity, more than 3 million people annually visit the over 42,000 acres now protected for conservation and recreation within Chatfield Basin. Plum Creek flows through a part of Chatfield Basin. In 1965 this was the site of a catastrophic flood event whose consequences are being studied. US 85 is a corridor for human movement across the basin, and Plum Creek, with its riparian areas, is itself a corridor for wildlife movement. The US 85 corridor crosses many such wildlife corridors and also trails used by hikers and bikers. Planning the “green infrastructure” for these corridors is needed to link together a network of very special open places and to sustain natural values for both wildlife and recreation within Denver’s rapidly developing southern fringe.
Movement of wildlife across a busy US 85 is necessary to prevent isolation and fragmentation of natural habit. In time, the isolated sites become less hospitable to wildlife and plants. Species diversity is lost. The basin was identified as one of the top 17 priority conservation areas in Colorado by the Colorado Division of Wildlife and The Nature Conservancy. Within the basin are species of endangered plants and animals.
Seven key conservation corridors have been identified and six broad conservation areas deserve special attention for their natural values as educational resources. Roads such as US 85 alter the way streams and riparian areas function. Chemicals such as de-icers can contaminate surface and ground water. Roads facilitate the invasion of exotic plants. Roads displace and fragment or isolate wildlife habitat. Movement of wildlife becomes difficult across the new environment of concrete, asphalt, and huge, noisy, speeding objects. Mortality and injury for wildlife users becomes high. Crossing the road is often not easy or environmentally safe for human life. U.S. 85 is both a corridor and a barrier. This barrier needs to be permeable. Its intersections with non-motorized movement must be compatible with the needs of both wildlife and recreational users.
Analysis of the landscape is required to identify key points where crossings could occur. Many factors influencing wildlife behavior require analysis. Analysis of people behavior is needed too. What works for big game, elk, and deer, may not work for amphibians, mice, or even people. With study, ways to funnel all users toward designed and intended crossings can be found. Monitoring of how things work is essential.
Challenges of this planning project offer opportunities for innovation in design and collaboration among its many partners. These challenges also offers opportunities to think about highway design and, more broadly, about how transportation planning fits with watershed planning. Visit the Theo L. Carson Nature Center and talk with District staff about planning to protect wilderness on the urban fringe and design “green infrastructure.” The creative ideas being generated and lessons learned should be shared across Colorado and far beyond.

Colorado Riparian Association