News & Media

Tunnel, fence near Shingle Springs to help critters cross Hwy. 50 safely

by Tony Bizjak (The Sacramento Bee)
May 19, 2012

On a wooded and wildlife-rich stretch of Highway 50 in the foothills, Caltrans is about to launch an unusual road safety experiment – for critters and drivers alike.

The agency is building the Sacramento region’s first deer and large-animal road crossing, a $1.6 million tunnel and fence project, in hopes of reducing the amount of roadkill in the Highway 50 corridor.

Even as they put finishing touches on the tunnel east of Shingle Springs near the El Dorado Road exit, state Department of Transportation biologists acknowledge they can’t be sure how well it will work.

Will deer, coyotes, foxes, bobcats and mountain lions find their way to the 12-foot-by-12-foot concrete culvert? And will they choose to use it, or continue along the fence looking for an opening to make a dangerous dash across the four lanes above?

“No one location is going to solve the problem,” said Suzanne Melim, Caltrans biologist on the project. “I think it’ll work well.

“I look at this as a starting point in what will be a continual effort.”

The Highway 50 undercrossing is funded by a federal grant. But state officials acknowledge that spending money on an animal crossing when California faces a massive deficit could raise questions.

Caltrans officials say the decision is rooted in public safety: Collisions between cars and wild animals are a growing problem and can be fatal to drivers and wildlife.

Crossings also help sustain wildlife populations, biologists note, by helping animals get to and from feeding and breeding grounds.

While new to Sacramento proper, crossings for deer and other large wildlife have been built in the United States for decades. There are several on Interstate 80 east of Truckee and one on Highway 89 near Sierraville.

Florida has panther crossings. There’s a culvert for desert tortoises on Interstate 15 in Southern California. Canada has pioneered forest-like overcrossings for moose and elk.

Locally, the city of Davis tried an unsuccessful toad tunnel in the 1990s that it no longer maintains.

Research shows animals use crossings if they are designed correctly. Cameras at the state’s Highway 89 crossing show seemingly skittish deer darting through, as well as lumbering bear and smaller animals.

California had nearly 50 such wildlife crossings as of four years ago, according to a national study. But state officials acknowledge they still are in early stages of data collection and analysis on design and location of crossings. Caltrans does not yet keep a statewide inventory of where crossings are, much less detailed analysis of how they are working.

The Shingle Springs effort, which will be finished in June, shows there is still guesswork at play.

Caltrans applied for and won a federal grant several years ago to build a crossing somewhere along Highway 50. When officials did an initial analysis on the best place to put it, they came to a surprising and disconcerting conclusion:

There are no roadkill hot spots on Highway 50 in El Dorado County. Animals were being hit and killed in roughly equal numbers along the corridor. “There wasn’t that kind of ‘aha, this is the location,’ ” Melim said.

The spot east of Shingle Springs was chosen because the topography is suitable, the area has evidence of deer migration trails, there is adjacent publicly owned land, and because maintenance crews seasonally pick up animal carcasses there.

There are some concerns, as well, about the tunnel length. At 206 feet, it is long for a crossing and could have a cave-like feel that will initially scare some animals off. Patricia Cramer, a crossings expert at Utah State University, said “most deer won’t go through (for) the first year or two” in a tunnel that long. But she and others said ultimately more deer will use it as they get comfortable with it, and as pressure mounts to get to foraging habitat.

Caltrans officials are putting dirt over the concrete floor to create a natural surface and muffle echoes.

A 7-foot-tall fence will act as a funnel bringing animals to the tunnel. It will run at least 1,000 feet along the freeway from a hill on the west to an interchange on the east.

“They are logical (fence) endpoints,” Melim said.

The idea is to discourage animals from walking to the end of the fence and crossing the freeway there.

Caltrans will conduct photo monitoring to see how many animals use the new crosswalk.

Melim and others say they would like to build more crossings along Highway 50 and Interstate 80.

Wildlife biologists who have studied crossings and wildlife patterns say the ideal is to have a deer crossing every mile. Caltrans officials say that is not realistic.

Melim said the agency is working to include crossings as part of new projects, if a need is identified. A current road-widening project on Highway 49 south of Grass Valley includes a wildlife tunnel at one-third the cost of the Highway 50 project, she said, in part because it was included in the design.

Another cost-reducing option, promoted by UC Davis researcher Fraser Shilling and others, is to modify existing underpasses for rail lines, streams and even cars to include safe passage space for animals.

“If we think about (modifying) existing crossings, we can spend $10,000 instead of $1 million,” Shilling said.

Co-founder of the Road Ecology Center in Davis, Schilling is compiling a California roadkill database that he said shows there are, in fact, few real hot spots. “There is roadkill everywhere.”

Wildlife experts say the widespread nature of roadkill shows that large tracts of connected land are a key to preserving wildlife. Road crossings can be a valuable tool where habitat is bisected by busy roads.

Randy Morrison of the Mule Deer Foundation says, “It is not roads as much as development that interferes with migration.”

With that in mind, Caltrans officials have worked with the state Department of Fish and Game and local planning agencies to identify large blocks of wildlife habitat.

That information, they say, can be used by cities and counties to help determine where they should and shouldn’t grow, and how to keep key habitat areas from getting sliced up without connections between them.

“People are recognizing the wildlife aren’t going away just because you build homes,” Melim said. “People want to continue to see wildlife and not hit them.”

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