Publications

Data collected from May 1991 through September 1993 to determine seasonal fluctuations in ground-water levels and to estimate directions of ground-water flow in the saturated zone at selected study sites at the Iowa Management Systems Evaluation Area in the Walnut Creek Watershed are presented. The Walnut Creek Watershed is located on glacial deposits of Wisconsinan age in central Iowa...

Agriculture is a major land use in the coastal prairie area located in the southern part of the Trinity River Basin. Crops grown in the area include rice, sorghum, and soybeans. Pesticide- use estimates for the area show that compounds with the highest use are the herbicides: molinate, propanil, thiobencarb, metolachlor, acifluorfen, bentazon, and atrazine and the insecticides: carbaryl...

No abstract available.

The Georgia-Florida Coastal Plain study unit covers nearly 62,600 square miles along the southeastern United States coast in Georgia and Florida. In 1990, the estimated population of the study unit was 9.3 million, and included all or part of the cities of Atlanta, Jacksonville, Orlando, Tampa, and St. Petersburg. Estimated freshwater withdrawn in the study unit in 1990 was nearly 5,075...

No abstract available.

The recent expansion of Typha domingensis (Typha) into areas of the Everglades previously dominated by Cladium jamaicense (Cladium) communities has led to competing hypotheses about the importance of nutrient concentration vs. hydroperiod in controlling the distribution of these species. In this study, experimental mixtures of Typha domingensis, Cladium jamaicense, and Eleocharis...

Movement of agricultural chemicals alachlor, atrazine, cyanazine, deethylatrazine, deisopropylatrazine, and metolachlor between surface water and ground water is documented by data collected from May 1989 through July 1991 at an unfarmed study site adjacent to the Cedar River in Iowa. During periods of runoff, these chemicals moved from the Cedar River into the alluvial aquifer with bank...

The weight-of-evidence approach to the development of sediment quality guidelines (SQGs) was modified to support the derivation of biological effects-based SQGs for Florida coastal waters. Numerical SQGs were derived for 34 substances, including nine trace metals, 13 individual polycyclic aromatic hydrocarbons (PAHs), three groups of PAHs, total polychlorinated biphenyls (PCBs), seven...

About 23,000 annual peak streamflows and about 400 historical peak streamflows exist for about 950 stations in the surface-water data-collection network of Texas. These data are presented on a computer diskette along with the corresponding dates, gage heights, and information concerning the basin, and nature or cause for the flood. Also on the computer diskette is a U.S. Geological...

Water-level measurements were made during 1992-94 in 253 wells completed in the Black Creek aquifer in an approximately 2,550-square-mile area of Bladen, Hoke, Robeson, and Scotland Counties in the southern Coastal Plain of North Carolina. Water levels were measured in 56 wells in the fall of 1992, 135 wells in the fall of 1993, and 62 wells in the spring of 1994 to map the...

The U.S. Marine Corps Air Station, Cherry Point, North Carolina, is underlain by four freshwater-bearing aquifers--the surficial, Yorktown, and upper and lower Castle Hayne. The upper and lower Castle Hayne aquifers serve as the principal supply of freshwater for the Air Station. The potential for movement of contaminated water from the surficial aquifer downward to the water-supply...

No abstract available.