The Great Divide basin is located in the southern part of the state of Wyoming in USA. Wyoming is the second largest uranium province in that country after the Colorado Plateau. The Great Divide basin represents an intermontane depression of Tertiary age surrounded by major structural uplifts composed of Precambrian rocks including uraniferous Precambrian granite. The main uranium resources of the Great Divide basin are hosted in the weakly lithified sandstone of the Eocene Battle Spring Formation which terminates the sedimentary sequence at the basin. Uranium occurs in the form of rolls and the tabular mineralisation is usually associated with carbonaceous debris in the host sediments. Because of close spatial relationships between uranium and detrital carbonaceous debris the uranium mineralisation of the Great Divide basin is referred to as detrital carbon-uranium roll-type which is a special class of Phanerozoic sandstone hosted uranium deposits. The deposits of the Great Divide basin contain from 2 to 15 kt of U 3 O 8 each, which occurs as uranium rolls and tabular mineralisation, some of which is fault controlled. Their formation is related to multi-episodic uplifts of the Precambrian basement which is exposed along the margins of the basin.

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A study of residential canal system on the Mississippi Gulf Coast and adjacent natural water bodies was conducted to determine the relationship in flushing characteristics between man‐made and natural systems. The comparison was based on measurements of temperature, salinity, conductivity, coliform, pH, transparency, biological oxidation demand, dissolved oxygen, bathymetry, tides, water velocity, and Rhodamine dye concentrations. The results indicate that coliform bacteria increase with increasing distance of stations from St. Louis Bay and dissolved oxygen decreases in a similar manner. Biological oxidation demand was low at all stations; showing no differences between natural and man‐made systems. The canal system Studied was shallower than adjacent water bodies and water velocities in the canal system are a function of tidal amplitude while velocities in the river are affected by both tides and runoff. The other parameters measured show little or no differences between natural and man‐made systems, but reflect overall seasonal changes. Flushing rates between the residential canal systems and an adjacent natural system are equivalent on the basis of decline in dye concentrations measured over a five‐day period.