This cache is located in a roadside pull out just south of the animal crossing underpass. The bridge and the fence were put in a few years ago to give animals a safe way to get to the water. Fish and game posted the following in 2011:
For millennia, mule deer and elk have traveled to and from low elevation ranges where they spend the winter, to mountain meadows where they grow fat each summer feasting on the rich vegetation found at higher elevations. In doing so, they must cross State Highway 21. In recent years, from 75 to 200 or more mule deer and elk, crossing the highway between Boise and Robie Creek, have been killed by vehicles each year.
So far this spring, only one animal has died in the stretch with a recently completed wildlife underpass.