[en] During the summers of 1976, 1977, and 1978, 442 water and 1755 sediment samples were collected from 1801 locations within the 19 400 km² area of the Moab quadrangle. Water samples were collected from streams, springs, and wells; wet and dry sediment samples were collected both from stream channels and from springs. Each water sample was analyzed for 13 elements, including uranium, and each sediment sample was analyzed for 43 elements, including uranium, thorium, and vanadium. Uranium concentrations in water samples range from below the detection limit of 0.02 to 1874.22 ppB and have a median of 0.67 ppB and a mean of 8.46 ppB uranium. Nearly half of the water samples containing high uranium concentrations were downstream from workings within the Lisbon Valley or La Sal Creek mining areas. High uranium concentrations were also found in several water samples where uranium mineralization is not known. These samples are from streams and shallow wells that drain separate areas in the Morrison formation and in the Mancos shale. Uranium concentrations in sediment samples range from 0.74 to 108.6 ppM and have a median of 2.56 ppM and a mean of 3.06 ppM uranium. Most of the sediment samples containing >10 ppM U are directly downstream from mines or in the immediate vicinity of ore reduction plants. Only one sediment sample containing >10 ppM uranium is outside mining activity, but the uranium-to-thorium ratio (U/Th) indicates that this location might be associated with uranium mineralization east of the Uravan Mineral Belt