1. Map showing availability of hydrologic data published as of 1974 by the U.S. Environmental Data Service and by the U.S. Geological Survey and cooperating agencies, Colorado Springs-Castle Rock area, Front Range Urban Corridor, Colorado [cartographic material] Yale Public content 1975. 2013-06-13T13:36:51Z. 2013-06-26T19:51:05Z. Anna, Lawrence O. The Survey. English. Public. Colorado, Douglas County, Front Range (Colo. and Wyo.), El Paso County, Elbert County, Fremont County, and Teller County.