STS062-098-158 San Joaquin Valley, Lake McClure, and Don Pedro Reservoir, California, U.S.A. March 1994 The agriculturally rich San Joaquin Valley is captured in this low-oblique, north-northeast-looking photograph. The boundary is distinct between agricultural field patterns of the valley and the grass- and scrub-covered alluvial fan, which becomes more tree covered as the altitude of the Sierra Nevada Mountains increases. Two large reservoirs--broader and more northerly Don Pedro Reservoir, fed and drained by the Tuolumne River, and narrower and more southerly Lake McClure, fed and drained by the Merced River--modify the valley's water flow for drinking water and crop irrigation. The higher Sierra Nevada Mountains are visible to the east.