( 1) Abstract: Metropolitan Detroit ( USA) is underlain by unconsolidated sediments of glacial，glacial-lacustrine and fluvial origin. These sediments form a complex series of confined aquifers overlain by an extensive unconfined surficial aquifer. All surface w ater w ithin metropolitan Detroit originates from this complex system of aquifers. Groundw ater w ithin the near-surface unconfined aquifer discharges directly into the Rouge River，the dominant river in the metropolitan area. The Rouge River is a major tributary to the Detroit River，w hich empties into Lake Erie. Thousands of sites of environmental contamination are located w ithin metropolitan Detroit. The combination of contaminated sites and near-surface groundw ater that flow s and discharges into the Rouge River creates a significant potential for contamination to eventually migrate to the Great Lakes. The Rouge River is currently identified as an area of concern by the International Joint Commission ( IJC ) and represents a significant source of pollution to the Great Lakes. Key words: Near-surface aquifer; glacial deposits; urban environment; groundwater; environmental contamination
( 2) Abstract: The ability of sea water to flow into coastal or submarine cavities is surprising，in view of the fact that sea level is，for w ater，a level of minimum gravitational potential w here it can perform no w ork. To achieve a low er potential requires energy，the provision of w hich is an example of a completely original aspect of the interaction betw een subterranean hydrodynamics and marine hydraulics. We have studied a spectacular example of the simultaneous outflow of fresh w ater and inflow of salt w ater at a karstic spring running into a salt-w ater lagoon on the French Mediterranean coast，and w e suggest here a hypothesis to account for the surprising double-layered，tw o-directional flow observed. Key words: Limestone aquifer; karstic spring; salt water; fresh water; simultaneous flow
( 3) Abstract: In north-central Oregon a large area of near-zero near-surface conductive heat flow occurs in young volcanic rocks of the Cascade Rage. Recent advective heat flux measurements and a heat-budget analysis suggest that groundw ater circulation sw eeps sufficient heat out of areas w here rocks younger than 6 Ma ( million years ago) are exposed to account for the anomalously high advective and conductive heat discharge measured in older rocks at low er elevations. Earlier w orkers have proposed that an extensive midcrustal magmatic heat source is responsible for this anomalously high heat flow. Instead，high heat flow in the older rocks may be a relatively shallow phenomenon caused by regional groundw ater flow. Any deeper anomaly may be relatively narrow ，spatially variable，and essentially confined to the Quaternary ( less than 2 Ma) arc. Magmatic intrusion at a rate of 9 to 33 cubic kilometers per kilometer of arc length per million years can account for the total heat flow anomaly. Deep drilling in the areas of high heat flow in the older rocks could indicate w hich model is more appropriate for the near- surface heat flow data. Key words: Conductive heat flow ; water circulation; hot spring; thermal groundwater; magmatic intrusion
( 4) Abstract: Fresh water aquifers in small coral islands usually occur as thin lenses w hich are significantly influenced by stresses such as groundw ater pumping，sea tides，etc. Kavaratti，a coral island，is one of the 36 such islands in the Arabian Sea off the w estern coast of India. Detailed hydrogeological investigations w ere carried out to determine the quantity of fresh w ater that could be pumped in addition to the present usage. Salinity of groundw ater must remain w ithin permissible limits and a 2-D solute mass transport model w ith a vertical section of the island w as constructed by the computer code SUTRA. The model w as calibrated by obtaining a match of computed and observed values of the w ater table，tidal efficiency，and salinity of groundw ater at the w ater table. The model analysis show ed that the salinity of groundw ater continues to increase unless groundw ater pumping is kept below a certain rate. Groundw ater potential can be augmented by reducing the subsurface outflow to the sea and by raising the w ater table by a subsurface dam.
Key words: Island; water table; tidal effect; abstraction; sea water intrusion