Publications

The West Branch Susquehanna River basin has a drainage area of 6,955 square miles in north-central Pennsylvania and comprises Hydrologic Accounting Unit 020502. A National Stream Quality Accounting Network (NASQAN) waterquality data collection site, maintained by the U.S. Geological Survey, is located on the river near its mouth at Lewisburg, Pennsylvania. Water-quality data are collected at numer

The 245 water samples collected from 56 wells at 45 sites in surficial sand-plain aquifers that underlie 600 square miles of Douglas, Kandiyohi, Pope, and Stearns Counties in west-central Minnesota contained wide ranges in concentrations of some constituents--sulfate 2 to 160 mg/L (milligrams per liter), chloride 1.6 to 64 mg/L, nitrite plus nitrate nitrogen < (less than) 0.1 to 72 mg/L, ammonia <

Analytical solutions have been developed for many conceptual models of solute transport in groundwater (Bear 1979). Although these models usually rely on assumptions too restrictive for accurate description of actual field situations, they are useful in understanding groundwater transport and in evaluating the relative importance of the subsurface processes affecting transport. In addition, these

No abstract available.

As concern over the effects of trace amounts of pollutants has increased, so has the need for statistical methods that deal appropriately with data that include values reported as “less than” the detection limit. It has become increasingly common for water quality data to include censored values that reflect more than one detection limit for a single analyte. For such multiply censored data sets,

Research on microbial degradation of crude oil in the shallow subsurface at a spill site near Bemidji, Minn. (fig. C-l), began in 1983 (Hull, 1984; Chang and Ehrlich, 1984). The rate and extent of crude oil and model hydrocarbon biodegradation by the indigenous microbial community was measured in the laboratory at several concentrations of inorganic nutrients, conditions of oxygen availability, in

No abstract available.

No abstract available.

Whole-body samples of bluegills (Lepomis macrochirus) and common carp (Cyprinus carpio) from the San Joaquin River and two tributaries (Merced River and Salt Slough) were analyzed to determine if the concentrations of any of nine elements were elevated as a result of exposure of the fish to agricultural subsurface (tile) drainage water. Highest concentrations (μg/g dry weight) detected were as fol

The hydraulic potentiomanometer described herein consists of a potentiometer connected to a manometer by a flexible tube. The device is used to directly measure the direction of seepage as well as the hydraulic-head difference between groundwater and surface water. The device works most effectively in sandy materials. For accurate measurements the device must be free of air leaks.

Jumbo multiple plate samplers were suspended in a river at 0.3 and 1 m depth in one of three orientations: interplate spaces closed to downwelling light and open to flow, open to light and flow, or open to light and closed to flow. Mean numbers of colonizing taxa and individuals were not significantly different among orientations after eight weeks of submergence. All variables tested decreased sig

Longitudinal advective solute movement in heterogeneous porous media is investigated by considering the solute arrival time at a plane perpendicular to the mean fluid velocity. The moments of the solute arrival time are defined in terms of the stochastic properties of a statistically anisotropic hydraulic conductivity field. The flux‐averaged concentration is specified by introducing the moments o