Search USGS⌕ Search

Geology topics

W.V. Swarzenski

Publications and source records attributed to W.V. Swarzenski.

6 recordsLinked to original sources
USGS2007

Multi-channel resistivity investigations of the freshwater-saltwater interface: A new tool to study an old problem

It has been well established that fresh or brackish groundwater can exist both near and far from shore in many coastal and marine environments. The often permeable nature of marine sediments and the underlying bedrock provides abundant pathways for submarine groundwater discharge. While submarine groundwater discharge as a coastal hydrogeological phenomenon has been widely recognized, only recent advances in both geochemical tracers and geophysical tools have enabled a realistic, systematic quantification of the scales and rates of this coastal groundwater discharge. Here we present multichannel electrical resistivity results using both a time series, stationary cable that has 56 electrodes spaced 2 m apart, as well as a 120 m streaming resistivity cable that has two current-producing electrodes and eight potential electrodes spaced 10 m apart. As the cable position remains fixed in stationary mode, we can examine in high resolution tidal forcing on the freshwater-saltwater interface. Using a boat to conduct streaming resistivity surveys, relatively large spatial transects can be rapidly (travel speed -2-3 knots) acquired in shallow (-1-20 m) waters. Sediment formation factors, used to convert resistivity values to salinity, were calculated from porewater and sediment samples collected during the installation of an offshore well in Tampa Bay, Florida, USA. Here we examine the seabed resistivity from sites within Tampa Bay using both stationary and streaming configurations and discuss their overall effectiveness as a new tool to examine the dynamic nature of the freshwater-saltwater interface.

Conference Paper↗
USGS1967

Progress report: Ground-water appraisal of Cuyama Valley, California

Ground-water withdrawals in Cuyama Valley (fig. 1) have increased about 500 percent since the early forties, and since about 1947 annual withdrawal has exceeded the estimated perennial yield of the basin. This has caused a general decline of water levels in the valley, and a well-defined cone of depression about 2 by 6 miles in area, reflecting a maximum water-level decline of about 140 feet, has developed near Cuyama. Continued overdraft will increase pumping lifts until pumping costs are no longer economical. The U.S. Geological Survey, in cooperation with the Santa Barbara County Water Agency, has been engaged in a water-resources investigation of the area during the past year. Preliminary findings are summarized in this progress report, which has been prepared at the request of the Santa Barbara County Water Agency. Ground water in Cuyama Valley is replenished mostly by rain on a watershed of about 700 square miles (fig. 2). Most of that area, at altitudes from 2,000 to 5,000 feet above sea level, receives less than 14 inches of precipitation a year. Somewhat greater precipitation, about 24 to 30 inches, occurs in the headwater region of the Cuyama River and on the crest of the Sierra Madre Mountains, where altitudes exceed 7,000 feet. However, only a small part of the drainage from these highland areas reaches the Cuyama ground-water basin. In the valley itself the average annual rainfall is less than 10 inches. The average annual rainfall for the 21-year period (1945-65) at Cuyama is 5.79 inches (fig. 3). Most of the rain falls in winter and spring.

California↗
USGS1960

Position of the salt-water body in the magothy(?) formation in the Cedarhurst-Woodmere area of southwestern Nassau county, Long Island, N.Y.

The position and chloride concentration of a sizable body of salt water , moving slowly landsyard from the south-shore bays of Long Island and the Atlantic Ocean were defined by recent test drilling in the Cedarhurst-Woodmere area of southwestern Nassau County, Long Island, N. Most of the salt-water body is in the lower part of a permeable artesian aquifer; the lowermost part of the salt-water body is in clay deposits underlying the permeable aquifer. The upper limit of the salt-water body in this area was found at depths increasing progressively in a landward direction. It was 318 feet below sea level at a well in Cedarhurst and 541 feet below sea level at a well in Woodmere. The lower limit of the salt-water body was determined at depths between 578 and 630 feet below sea level in the Cedarhurst-Woodmere area. The salt-water body is more than 300 feet thick at a well in Cedarhurst, and it thins out to zero in the vicinity of a pumping center about 1- miles northeast of the Cedarhurst well. Chloride concentration in the salt-water body in the Cedarhurst-Woodmere area ranged from about 40 to 16,000 ppm (parts per million). Isochlors define a zone of diffusion about a mile wide in the Cedarhurst-Woodmere area. They indicate a thickness of diffused water ranging from a few tens to more than 150 feet vertically. Electrical-log data show that the upper boundary of the salt-water body moved upward 21 feet between 1952 and 1958 at a site in Woodmere about half a mile southwest of the pumping center. ' From this information it is inferred that between 1952 and 1958 the leading edge of the saltwater front moved landward about 2,000 feet toward the pumping center.

New York↗