Publications

Regional regression equations were developed for estimating selected natural—unaffected by alteration—streamflows of specific flow durations and low-flow frequency statistics for ungaged stream sites in Rhode Island. Selected at-site streamflow statistics are provided for 41 long-term streamgages, 21 short-term streamgages, and 135 partial-record stations in Rhode Island, eastern Connecticut, and

We analyze intervals between eruptions (IBEs) data acquired between 2001 and 2011 at Daisy and Old Faithful geysers in Yellowstone National Park. We focus our statistical analysis on the response of these geysers to stress perturbations from within the solid earth (earthquakes and earth tides) and from weather (air pressure and temperature, precipitation, and wind). We conclude that (1) the IBEs o

Cold groundwater discharge to streams and rivers can provide critical thermal refuge for threatened salmonids and other aquatic species during warm summer periods. Climate change may influence groundwater temperature and flow rates, which may in turn impact riverine ecosystems. This study evaluates the potential impact of climate change on the timing, magnitude, and temperature of groundwater disc

A 17-year record (1995–2012) of a suite of environmental tracer concentrations in discharge from 34 springs located along the crest of the Blue Ridge Mountains in Shenandoah National Park (SNP), Virginia, USA, reveals patterns and trends that can be related to climatic and environmental conditions. These data include a 12-year time series of monthly sampling at five springs, with measurements of t

Alkylphenolic chemicals (APCs) and hormones were measured six times from February through October 2007 in three Minnesota streams receiving wastewater to identify spatial and temporal patterns in concentrations and in estrogen equivalency. Fish were collected once during the study to evaluate endpoints indicative of endocrine disruption. The most commonly detected APCs were 4-tert-octylphenol and

One by-product of advances in modern chemistry is the accumulation of synthetic chemicals in the natural environment. These compounds include contaminants of emerging concern (CECs), some of which are endocrine disrupting compounds (EDCs) that can have detrimental reproductive effects. The role of sediments in accumulating these types of chemicals and acting as a source of exposure for aquatic o

We developed a process model LM3-TAN to assess the combined effects of direct human influences and climate change on terrestrial and aquatic nitrogen (TAN) cycling. The model was developed by expanding NOAA's Geophysical Fluid Dynamics Laboratory land model LM3V-N of coupled terrestrial carbon and nitrogen (C-N) cycling and including new N cycling processes and inputs such as a soil denitrificatio

Pesticide mixtures are common in streams with agricultural or urban influence in the watershed. The Pesticide Toxicity Index (PTI) is a screening tool to assess potential aquatic toxicity of complex pesticide mixtures by combining measures of pesticide exposure and acute toxicity in an additive toxic-unit model. The PTI is determined separately for fish, cladocerans, and benthic invertebrates. Thi

Sabkhat (Salt flats) are common geographic features of low-lying marine coastal areas that develop under hyper-arid climatic conditions. They are characterized by the presence of highly concentrated saline solutions and evaporitic minerals, and have been cited in the geologic literature as present-day representations of hyper-arid regional paleohydrogeology, paleoclimatology, coastal processes, an

The recent climate-exacerbated mountain pine beetle infestation in the Rocky Mountains of North America has resulted in tree death that is unprecedented in recorded history. The spatial and temporal heterogeneity inherent in insect infestation creates a complex and often unpredictable watershed response, influencing the primary storage and flow components of the hydrologic cycle. Despite the incre

Groundwater quality in the 8,806-square-mile Klamath Mountains (KLAM) study unit was investigated by the U.S. Geological Survey (USGS) from October to December 2010, as part of the California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment (GAMA) Program’s Priority Basin Project (PBP). The GAMA-PBP was developed in response to the California Groundwater Qu

A three-dimensional groundwater-flow model is coupled with the particle-tracking program MODPATH to delineate zones of contribution to wells pumping from the Magothy aquifer and supplying water to a chlorinated volatile organic compound removal plant at site GM–38, Naval Weapons Industrial Reserve Plant, Bethpage, New York. By use of driller’s logs, a transitional probability approach generated th