Publications

Damaged and immature specimens often result in macroinvertebrate data that contain ambiguous parent-child pairs (i.e., abundances associated with multiple related levels of the taxonomic hierarchy such as Baetis pluto and the associated ambiguous parent Baetis sp.). The choice of method used to resolve ambiguous parent-child pairs may have a very large effect on the characterization of

We examined potential sources and the temporal dynamics of arsenic (As) in the slightly alkaline waters of the Wallkill River, northwestern New Jersey, where violations of water-quality standards have occurred. The study design included synoptic sampling of stream water and bed sediments in tributaries and the mainstem, hyporheic-zone/ground water on the mainstem, and seasonal and...

Transport and chemical transformations of dissolved and colloidal Al, Fe, Cu and Zn were studied by detailed sampling in the mixing zone downstream from the confluence of Cement Creek (pH 4.1) with the Animas River (pH 7.6). Complete mixing resulted in circumneutral pH in the downstream reach of the 1300 m study area. All four metals were transported through this mixing zone without...

Microbially catalyzed cleavage of the imadazole ring of caffeine was observed in stream sediments collected upstream and downstream of municipal wastewater treatment plants (WWTP) in three geographically separate stream systems. Microbial demethylation of the N-methyl component of cotinine and its metabolic precursor, nicotine, also was observed in these sediments. These findings...

Background As the population and demand for safe drinking water from domestic wells increase, it is important to examine water quality and contaminant occurrence. A national assessment in 2006 by the U.S. Geological Survey reported findings for 55 volatile organic compounds (VOCs) based on 2,401 domestic wells sampled during 1985–2002.Objectives We examined the occurrence of individual...

Significant Findings When water is released through the spillways of dams, air is entrained in the water, increasing the downstream concentration of dissolved gases. Excess dissolved-gas concentrations can have adverse effects on freshwater aquatic life. The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers, collected dissolved-gas and water-temperature...

This is the forty-fourth in a series of annual reports that describe ground-water conditions in Utah. Reports in this series, published cooperatively by the U.S. Geological Survey and the Utah Department of Natural Resources, Division of Water Resources and Division of Water Rights, and the Utah Department of Environmental Quality, Division of Water Quality, provide data to enable...

In the late winter and early spring of 2006 an unusual white deposit was observed on rocks and margins of streambeds in a number of park streams. Inquiries were made to park staff and scientists studying water resources in the park as to what the deposit was and did it pose any type of risk. A number of explanations were proposed, but it was not until samples were collected and examined...

Methods and guidelines for developing and using mathematical models Turn to Effective Groundwater Model Calibration for a set of methods and guidelines that can help produce more accurate and transparent mathematical models. The models can represent groundwater flow and transport and other natural and engineered systems. Use this book and its extensive exercises to learn methods to fully...

The nations of the world suffer both from the deleterious effects of some natural and human-altered fluxes of fluvial sediment and a lack of consistent and reliable information on the temporal and spatial occurrence of fluvial sediments. Decades ago, this difficulty was unavoidable due to a lack of understanding of the magnitude and scope of environmental influences exerted by fluvial...

Phenology is the study of periodic plant and animal life cycle events, how these are influenced by seasonal and interannual variations in climate, and how they modulate the abundance, diversity, and interactions of organisms. The USA National Phenology Network (USA-NPN) is currently being organized to engage federal agencies, environmental networks and field stations, educational...

Lignin phenol concentrations and compositions were determined on dissolved organic carbon (DOC) extracts (XAD resins) within the Sacramento-San Joaquin River Delta (the Delta), the tidal freshwater portion of the San Francisco Bay Estuary, located in central California, USA. Fourteen stations were sampled, including the following habitats and land-use types: wetland, riverine...