Map of catchment areas & valleys of Rio Grande Del Norte, of "Upper Rio Grande," the 160 miles Section in Colorado, and of "Middle Rio Grande," the 250 miles Section in New Mexico, above the U.S.R.S. "Elephant Butte" Project in Lower Valleys. Showing locations & positions of notable topographic & physical features, catchment & drainage areas, basins, divides, mountains, stream-courses, state & county lines, principle places, and railroads.