BY THE OPTIMIST DAILY EDITORIAL TEAM
Nine months in, North America’s largest wildlife overpass has cut vehicle collisions on a stretch of Interstate 25 in Colorado by 91 percent. Before it opened, that corridor was averaging roughly one deer hit per day during peak migration.
The crossing, a 209-by-200-foot structure near the Greenland exit between Larkspur and Monument, opened in December. It came in ahead of schedule and under budget. Five underpasses and miles of fencing channel animals toward the safe crossings.
One deer a day, then nothing
For decades, I-25 in Douglas and El Paso counties cut across seasonal migration corridors for elk and pronghorn with no way across. Colorado Parks and Wildlife biologist Brandon Marette called it “an effective wall that they had to play Frogger and try to get across.” Pronghorn ranging between Trinidad and Greenland had nowhere to go. The highway averaged roughly one deer hit per day during spring and fall migration.
Elk herds and returning pronghorn
Cameras at the crossing have since recorded elk herds crossing in groups and pronghorn on the west side of I-25 for the first time in decades. “For decades, pronghorn going from Trinidad to Greenland were looking for a place to cross on I-25,” said Chuck Attardo, CDOT Environmental Manager. “And when we open this up, we have pronghorn on video using the overpass, and for the first time in decades they’re coming over here to the west side.”
Bears, deer, and coyotes have also been recorded. One image caught an elk cow leading her calf under the highway. Marette said it was the payoff for six years of work.
Not just the big animals
Elk and pronghorn were the primary targets, but wildlife managers didn’t stop there.
Covered pathways for small mammals
Biologists piled wood into corridors on the overpass to give small mammals covered routes across. “So that coyotes, foxes, and hawks don’t pick them off when they’re trying to cross I-25 on the overpass,” Marette said. The Preble’s meadow jumping mouse, which is federally threatened, lives in the area and now uses the crossing. Northern leopard frogs, reptiles, and amphibians are crossing too. “We’re not just focused on the big game species, but also on the smaller,” Marette said.
Native vegetation on the overpass surface is still being established. This year’s drought slowed germination; new topsoil and reseeding are planned for next year.
The economics for Colorado’s wildlife crossings
Under budget, ahead of schedule
The project received $22 million in federal infrastructure funds and $8 million from the state. Contractor Kraemer North America finished it for $15 million, about half the total. Attardo says crossings like this typically recoup their cost in about 15 years through the accidents, property damage, and service costs they prevent. “They pay for themselves in about 15 years because of all those accidents that they prevent. So why wouldn’t you do more of these?”
Funding the next round of crossings
A recently passed state law is expected to generate around $3 million per year for wildlife mitigation projects. That money would go toward matching larger federal grants. CDOT has a list of priority corridors: Raton Pass near the New Mexico border, US-40 near Empire, State Highway 160 near Mesa Verde, East Vail Pass, US-40 near Craig, US-287 near Fort Collins, and several sites near Boulder.
What it takes to make one happen
The Greenland crossing took six years and a coalition: the Federal Highway Administration, CDOT, Colorado Parks and Wildlife, Douglas County, the Douglas Land Conservancy, and the Colorado Cattlemen’s Agricultural Land Trust. Conservation easements on both sides of the highway made it viable.
“Everybody marching in the same direction,” Attardo said. “I really can’t stress enough how important it is to have leadership on your side when you’re trying to do big projects like this.”
The Douglas Land Conservancy holds over 28,500 acres in the region. Executive director Laura Sanford put it simply: “It’s not just for you; it is for everyone.”
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