Publications

The population dynamics of large, long-lived mammals are particularly sensitive to changes in adult survival. Understanding factors affecting survival patterns is therefore critical for developing and testing theories of population dynamics and for developing management strategies aimed at preventing declines or extinction in such taxa. Few studies have used modern analytical approaches...

The NAWQA Program is assessing the water-quality conditions of more than 50 of the Nation's largest river basins and aquifers, known as Study Units. Collectively, these Study Units cover about one-half of the United States and include sources of drinking water used by about 70 percent of the U.S. population. Comprehensive assessments of about one-third of the Study Units are ongoing at a...

The quality of urban stormwater is characterized with respect to 188 properties and constituents. Event-mean concentrations and loads for three land uses (residential, industrial, commercial), and annual loads for 12 selected properties and constituents for 26 gaged basins in the DallasFort Worth study area are presented. During February 1992–June 1993, 182 water samples from the 26...

From January 1993 through March 1994, circulation patterns and water- quality characteristics in Lake Hickory varied seasonally and were strongly influenced by inflows from Rhodhiss Dam. The upper, riverine portion of Lake Hickory was unstratified during much of the study period. Downstream from the headwaters to Oxford Dam, Lake Hickory thermally stratified during the summer of 1993...

This report is one in an annual series of reports that depicts water-level altitudes and water-level changes since 1990 in the Chicot and Evangeline aquifers in Fort Bend County and adjacent areas, Texas. The report, prepared in cooperation with the Ford Bend Subsidence District, presents maps for the Chicot and Evangeline aquifers showing the approximate water-level altitudes in wells...

The U.S. Geological Survey (USGS) has monitored the water quality in the Rio Grande Basin as part of the redesigned National Stream Quality Accounting Network (NASQAN) since 1995 (Hooper and others, 1997). The NASQAN program was designed to characterize the concentrations and transport of sediment and selected chemical constituents found in the Nation's large rivers-including the...

Fishing with a variety of methods and gears, including traps, is allowed within the waters of Virgin Islands National Park (St. 10hn, U.S. Virgin Islands). Randall's 1 9 6 1 observation of the effects of overushing in nearshore waters off Sto John has been followed by three and a half decades of reports documenting the declining reef fish catch in the Virgin Islands and much of the...

The relative abilities of sediment concentrations of simultaneously extracted trace metal: acid-volatile sulfide (SEM: AVS) and dry weight-normalized trace metals to correctly predict both toxicity and nontoxicity were compared by analysis of 77 field-collected samples. Relative to the SEM:AVS concentrations, sediment guidelines based upon dry weight-normalized concentrations were...

A porous graphitic carbon column (Hypercarb) was used for the fractionation of polychlorinated biphenyls (PCBs) into classes of 2-4 ortho chlorines, 1 ortho chlorine and 0 ortho chlorine congeners. A method was developed that combined the fractionation of PCBs, polychlorinated dibenzo-p-dioxins and dibenzofurans in a variety of biotic environmental samples. Many of these samples have...

Numerous studies are being conducted to investigate the occurrence, fate, and effects on human health and the environment from the extensive worldwide use of herbicides to control weeds. Few studies, however, are considering the degradates of these herbicides in their investigations. Our study of herbicides in aquifers across Iowa found herbicide degradates to be prevalent in ground...

A progressive classification of a marsh and forest system using Landsat Thematic Mapper (TM), color infrared (CIR) photograph, and ERS-1 synthetic aperture radar (SAR) data improved classification accuracy when compared to classification using solely TM reflective band data. The classification resulted in a detailed identification of differences within a nearly monotypic black needlerush...

No abstract available.