hoover dam on the colorado river, lake mead, southwest desert, arizona and nevada border

america american and arizona attraction bathtub blocks border bridge callaghan canyon change climate colorado concrete dam desert destination dropping drought dry end environment extreme flow generation henderson high hoover hydro hydroelectric imposing intake into jutting lake las level levels low mead memorial mike nature nevada north of outdoor outdoors pat reservoir rings river road rocks rocky side south southern southwest southwestern states structure the tillman tourism tourist towers united usa vegas water west western where