Thursday, April 2, 2015

The Laramie Basin

North of Ft. Collins, Colorado, US 287 angles northwest, climbing into the Front Range foothills.  It then turns northward, passing through a scenic landscape of hogbacks, ridges, rock spires and domes; initially crossing foothill shrublands, it cuts through ponderosa parklands as it nears the Wyoming border.  Just beyond that border, the highway crosses a low pass, leaving the watershed of the Cache la Poudre and descending into the Laramie Basin (also called the Laramie Plains) which has an average elevation of about 8000 feet.

The Laramie River rises near Cameron Pass, in Colorado, flowing northward along the eastern base of the Medicine Bow Mountains.  Entering Wyoming, the river veers northeastward across its broad basin,  cuts northward through Laramie, enters Wheatland Reservoir and then turns eastward once again, carving a canyon through the Laramie Mountains before joining the North Platte River.  The latter mountains form the eastern wall of the Laramie Basin and outcrops of red Pennsylvanian sandstone adorn their western flank.  On the west side of the Laramie Plains is the massive bulk of the Snowy Range, Wyoming's portion of the Medicine Bow Mountains.

The semiarid Laramie Basin is underlain with shales and sandstones from the Cretaceous Seaway; since the soil is thin and the water table is high, the Laramie Plains are used primarily for ranching.  Pronghorns are abundant on the grasslands and numerous lakes dot the basin, attracting migrant and resident waterfowl and the raptors that pursue them; on my visit yesterday, I encountered several bald eagles, a peregrine falcon, a flock of American white pelicans and a wide variety of ducks.  Salt flats and ephemeral pools also characterize the Laramie Plains, attracting killdeer, white-faced ibis, American avocets and migrant shorebirds.  Finally, three National Wildlife Refuges lie within the basin: Bamforth, Mortenson Lake and Hutton Lake NWRs.