The Aswan High Dam, which was dedicated in 1971, impounded the water of the Nile River and created Lake Nasser, one of the world’s largest artificial lakes, which extends into northern Sudan. The dam provides major benefits to Egypt—flood control for the Nile River; increased irrigable land area; and much needed hydroelectric power (about 40 percent of the country’s electricity). The dam has also created a problem—the amount of silt that formerly replenished the cultivated farmlands downstream is no longer carried to the lower reaches of the Nile River and delta. The differences in general topography and surface composition on either side of the Nile River are apparent. The west bank of the river in this hot, desert climate appears to be more sandy with a few low escarpments and hills; whereas, the east bank has a more rugged appearance with rock outcrops, escarpments, and several well-entrenched, intermittently flowing stream channels (wadis). An airport runway is immediately west of the dam.