National Water-Quality Assessment Program; the Mississippi Embayment
Explore the source record for details and available documents.
Fact Sheet↗
Geology topics
Michael J. Mallory
Publications and source records attributed to Michael J. Mallory.
Approximate potentiometric surface for the aquifer unit A4, southeastern coastal plain aquifer system of the United States, prior to development
A generalized potentiometric surface map prepared as part of a regional analysis of sand aquifer system defines the altitude of water levels under pre-development conditions for aquifer unit A4, the lowermost group of aquifers in the sand aquifer system. Aquifer unit A4, consisting of Upper and Lower Cretaceous sands, is under artesian conditions except locally in the recharge areas. The regional flow direction is to the rivers in the area where the unit outcrops and southward to the Gulf of Mexico in Mississippi, Alabama, and West Georgia. In coastal Georgia and South Carolina, the direction of flow is east northeast parallel to the coast and into North Carolina. (USGS)
Water-Resources Investigations Report↗
Addendum to sources of powerplant cooling water in the desert area of Southern California: a reconnaissance study
A hydrologic reconnaissance study was made in five basins in southern California previously classified as suitable for providing sufficient ground water for cooling a 1,000-megawatt electric-power generating plant. The criteria used to evaluate the basins were (1) theoretical aquifer response to pumping, (2) alternative sources of water, and (3) chemical quality of water. The basins were ranked relative to each other for the three criteria and in overall suitability. On the basis of subjective analysis, the basins were ranked in the following order for overall suitability: (1) Calzona-Vidal Valley, (2) Middle Amargosa Valley, (3) Chuckwalla Valley, (4) Soda Lake Valley, and (5) Caves Canyon Valley. (USGS)
Open-File Report↗
Potential for using the Upper Coachella Valley ground-water basin, California, for storage of artificially recharged water
This report presents a preliminary evaluation of the geohydrologic factors affecting storage of water by artificial recharge in the upper Coachella Valley, Calif. The ground-water basin of the upper Coachella Valley seems to be geologically suitable for large-scale artificial recharge. A minimum of 900 ,000 acre-feet of water could probably be stored in the basin without raising basinwide water levels above those that existed in 1945. Preliminary tests indicate that a long-term artificial recharge rate of 5 feet per day may be feasible for spreading grounds in the basin if such factors as sediment and bacterial clogging can be controlled. The California Department of Water Resources, through the Future Water Supply Program, is investigating the use of ground-water basins for storage of State Water Project water in order to help meet maximum annual entitlements to water project contractors. (USGS)
Open-File Report↗
Potential effects of increased ground-water pumpage on Barka Slough, San Antonio Creek Valley, Santa Barbara County, California
Ground-water use in San Antonio Creek valley is expected to increase significantly as a result of planned extensive agricultural development in the basin. The effects of this additional stress on the ground-water system, particularly on the environmentally sensitive Barka, Slough, are of concern in the basin. Expectations of the developer are that about 6,640 acre-feet per year of additional consumptive ground-water use will be required to irrigate an agricultural development of 2,500 acres of vineyards and 1,200 acres of truck-farmed vegetables. This represents an increase in net basin pumpage of about 60 percent. The developer plans to obtain this water from 12 large-diameter irrigation wells in the Harris Canyon area. Analysis of the potential drawdowns in the vicinity of Barka Slough, by using the Theis nonequilibrium formula, indicates that drawdowns would average 6 feet after 10 years of pumping and would eventually exceed 10 feet. Because the artesian head in the aquifer that supplies the slough is generally less than 3 feet above land surface, these declines would probably mean that the wetlands of Barka Slough would disappear. An empirical relation, based on historical records of base flow in San Antonio Creek and net pumpage in the basin, also indicates that the additional irrigation withdrawals would cause base flow in San Antonio Creek to cease. Both of these analyses consider the effects of only this particular agricultural development, which would be in addition to any decline caused by other increases in pumpage in the basin.
California↗
Water-level predictions for Indian Wells Valley ground-water basin, California, 1978
Ground-water pumpage in Indian Wells Valley, virtually a closed basin in the Mojave Desert of southern California, has increased gradually since 1945 and presently exceeds the long-term mean annual recharge (perennial supply). In order to aid in the understanding and management of the ground-water basin, a digital ground-water model was constructed by the U.S. Geological Survey. Since the original development of this model, conditions in the basin, including areal distribution and rates of ground-water pumpage, have changed. The results of the present simulation for the period 1969-76 constitute a second verification of the original model. Calculated heads for 1976 agree well with the observed heads, indicating a good calibration of the original model. A predictive simulation for the period 1977-2020 used pumpage values increasing from about 15,500 acre-feet per year to about 26,000 acre-feet per year. The pumpage used in this report reflects a slightly slower growth rate and a more concentrated pattern of development than that investigated when the model was originally developed. The effects of this pattern of pumpage are reflected in the water levels simulated by the model. Predicted drawdowns for 1983 are less extensive but locally more severe than those predicted earlier. The reversal of the hydraulic gradient between China Lake playa and the city of Ridgecrest, as produced by these drawdowns by the year 2020, suggests that the water-quality effects of such drawdowns should be investigated, as this could result in inferior water from the China Lake playa area flowing southward into areas of withdrawal.
California↗