The giant Elephant Butte Reservoir, impounded behind the dam five miles
east of Truth or Consequences, provides year-around fishing, boating,
water skiing, and camping. Built in brown to gray Cretaceous sandstone
and shale, the dam is overlooked by the brownish-black volcanic neck
that is Elephant Butte. Eastern shores are carved from the purplish and
maroon McRae layers. This is the main storage reservoir for the water
that irrigates the lush Rio Grande Valley to the south near Las Cruces
and El Paso.