Publications

Phosphorus from natural and human sources is likely to be discharged from groundwater to streams in certain geochemical environments. Water-quality data collected from 1991 through 2007 in paired networks of groundwater and streams in different hydrogeologic and land-use settings of the Piedmont, Blue Ridge, and Valley and Ridge Physiographic Provinces in the eastern United States were...

During 2007 and 2008, the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, collected quarterly depth-discrete measurements of fluid pressure and temperature in six boreholes located in the eastern Snake River Plain aquifer of Idaho. Each borehole was instrumented with a multilevel monitoring system consisting of a series of valved measurement ports, packer...

In addition to the Greenland Ice Sheet, the Arctic contains a diverse array of smaller glaciers ranging from small cirque glaciers to large ice caps with areas up to 20 000 km 2 . Together, these glaciers cover an area of more than 400 000 km 2 , over half the global area of mountain glaciers and ice caps. Their total volume is sufficient to raise global sea level by an average of about...

A series of widespread, large, low-pressure systems in southern New England in late February through late March 2010 resulted in record, or near record, rainfall and runoff. The total rainfall in the region during this period ranged from about 17 to 25 inches, which coupled with seasonal low evaporation, resulted in record or near record peak flows at 13 of 37 streamgages in central and...

Increasing salinity loading in the Colorado River has become a major concern for agricultural and municipal water supplies. The Colorado Salinity Control Act was implemented in 1974 to protect and enhance the quality of water in the Colorado River Basin. The U.S. Geological Survey, in cooperation with the Bureau of Reclamation and the Colorado River Salinity Control Forum, summarized...

Pilot points have been used in geophysics and hydrogeology for at least 30 years as a means to bridge the gap between estimating a parameter value in every cell of a model and subdividing models into a small number of homogeneous zones. Pilot points serve as surrogate parameters at which values are estimated in the inverse-modeling process, and their values are interpolated onto the...

The project was initiated in April 2010, and to date has included four sampling events of surface water (April, May, June/July, and August 2010) and five sampling events of biota (April, May, June/July, August, and September 2010) and three sampling events for surface sediment (May, June/July, and August 2010). This annual report briefly summarizes our progress to date.

No abstract available.

The concept of a nonreactive or conservative tracer, commonly invoked in investigations of solute transport, requires additional study in the context of electrical geophysical monitoring. Tracers that are commonly considered conservative may undergo reactive processes, such as ion exchange, thus changing the aqueous composition of the system. As a result, the measured electrical...

No abstract available.

Two hydrologic models, MODFLOW with the Farm Process (MF-FMP) and the Integrated Water Flow Model (IWFM), are compared with respect to each model’s capabilities of simulating land-use hydrologic processes, surface-water routing, and groundwater flow. Of major concern among the land-use processes was the consumption of water through evaporation and transpiration by plants. The comparison...

More than half of the original Everglades extent formed a patterned peat mosaic of elevated ridges, lower and more open sloughs, and tree islands aligned parallel to the dominant flow direction. This ecologically important landscape structure remained in a dynamic equilibrium for millennia prior to rapid degradation over the past century in response to human manipulation of the...