Geology topics

Anthony S. Navoy

Publications and source records attributed to Anthony S. Navoy.

6 recordsLinked to original sources

USGS2015

Evolution of mid-Atlantic coastal and back-barrier estuary environments in response to a hurricane: Implications for barrier-estuary connectivity

Assessments of coupled barrier island-estuary storm response are rare. Hurricane Sandy made landfall during an investigation in Barnegat Bay-Little Egg Harbor estuary that included water quality monitoring, geomorphologic characterization, and numerical modeling; this provided an opportunity to characterize the storm response of the barrier island-estuary system. Barrier island morphologic response was characterized by significant changes in shoreline position, dune elevation, and beach volume; morphologic changes within the estuary were less dramatic with a net gain of only 200,000 m 3 of sediment. When observed, estuarine deposition was adjacent to the back-barrier shoreline or collocated with maximum estuary depths. Estuarine sedimentologic changes correlated well with bed shear stresses derived from numerically simulated storm conditions, suggesting that change is linked to winnowing from elevated storm-related wave-current interactions rather than deposition. Rapid storm-related changes in estuarine water level, turbidity, and salinity were coincident with minima in island and estuarine widths, which may have influenced the location of two barrier island breaches. Barrier-estuary connectivity, or the transport of sediment from barrier island to estuary, was influenced by barrier island land use and width. Coupled assessments like this one provide critical information about storm-related coastal and estuarine sediment transport that may not be evident from investigations that consider only one component of the coastal system.

New Jersey↗

USGS2005

Vulnerability of production wells in the Potomac-Raritan-Magothy aquifer system to saltwater intrusion from the Delaware River in Camden, Gloucester, and Salem Counties, New Jersey

The Potomac-Raritan-Magothy aquifer system is hydraulically connected to the Delaware River in parts of Camden and Gloucester Counties, New Jersey, and has more limited contact with the river in Salem County, New Jersey. The aquifer system is used widely for water supply, and 122 production wells that are permitted by the New Jersey Department of Environmental Protection to pump more than 100,000 gallons per year in the three counties are within 2 miles of the river. During drought, saltwater may encroach upstream from the Atlantic Ocean and Delaware Bay to areas where the aquifer system is recharged by induced infiltration through the Delaware River streambed. During the drought of the mid-1960's, water with a chloride concentration in excess of potability standards (250 mg/L (milligrams per liter)) encroached into the reach of the river that recharges the aquifer system. The vulnerability of the major production wells in the area to similar saltwater encroachment in the future is a concern to water managers. This vulnerability was evaluated by investigating two scenarios: (1) a one-time recurrence of the conditions approximating those that occurred in the1960's, and (2) the recurrence of those same conditions on an annual basis. Results of ground-water-flow simulation in conjunction with particle tracking and one-dimensional transport analysis indicate that the wells that are most vulnerable to saltwater intrusion are those in the Morris and Delair well fields in Camden County. A single 30-day event during which the concentration of dissolved chloride or sodium exceeds 2,098 mg/L or 407 mg/L, respectively, in the Delaware River would threaten the potability of water from these wells, given New Jersey drinking-water standards of 250 mg/L for dissolved chloride and 50 mg/L for dissolved sodium. This chloride concentration is about six times that observed in the river during the 1960's drought. An annually occurring 1-month event during which the concentrations of dissolved chloride or sodium in the river exceeds 1,818 mg/L or 358 mg/L, respectively, would threaten the potability of water from these wells. Wells outside the Morris and Delair well fields are substantially less vulnerable to the intermittent saltwater intrusion that was simulated.

New Jersey↗

USGS2003

Real-time surface-water monitoring in New Jersey, 2003

A network of 93 gaging stations that provide surface-water stage, flow (discharge), and tide-level data on a “realtime” basis through satellite, radio, and telephone telemetry is operating (May 2003) in New Jersey through a cooperative effort of the U.S. Geological Survey (USGS) and other agencies. The stream data from these stations are transmitted every 1 to 4 hours and then are immediately posted for viewing on the Internet. This fact sheet describes the “real-time” monitoring network, and the equipment used to measure stage and flow and to transmit the data for viewing on the Internet. Instructions for viewing the data are included.

New Jersey↗

USGS2003

Real-time ground-water-level monitoring in New Jersey, 2002

This network was created to provide data to indicate water-level trends in shallow ground-water systems within the State of New Jersey and to make the data available in the shortest time possible. The wells in this network are located throughout New Jersey (fig. 1) and were chosen because they are completed in shallow aquifers (table 1). The monitoring of shallow aquifers is important because these aquifers are relied on for water supply and irrigation. Additionally, the natural discharge from shallow aquifers provides base flow to streams. Water levels in these aquifers respond relatively quickly to precipitation and dry periods, so the rapid reporting of water-level data is necessary to follow trends. This network, for example, provides data that allow observation of the onset of drought conditions in ground water. Also, the data from this network can be used to estimate the most recent water-level trend in surficial-aquifer wells not outfitted with satellite telemetry.

New Jersey↗

USGS2002

Real-time ground-water-level monitoring in New Jersey

A network of seven observation wells that transmit ground-water-level data on a real-time basis through satellite telemetry is operating (started May 2001) in New Jersey through a cooperative effort of the U.S. Geological Survey (USGS) and the New Jersey Department of Environmental Protection (NJDEP). The water-level data from these observation wells are transmitted every 4 hours and then are immediately posted for viewing on the Internet. This fact sheet describes the rationale for real-time monitoring of ground-water levels, the design of the network, and the equipment used to measure water levels and transmit the data to the Internet. Instructions for viewing the data are included.

New Jersey↗

USGS1981

Water-resources information for the Withlacoochee River region, west-central Florida

Daily water use in the Withlacoochee River region in 1977 averaged about 2,005 million gallons per day, 94 percent of which was saline surface water used in thermoelectric power-generation cooling. Industrial and irrigation uses required 73 percent of the freshwater. The largest user of freshwater was Hernando County, using 43.0 million gallons per day. The ground-water system is comprised of up to three different aquifers--the surficial, the secondary artesian, and the Floridan. Little is known about the surficial and secondary artesian aquifers. The Floridan aquifer consists mostly of limestones and dolomites, and is as much as 1,500 feet thick. Transmissivities are known to be as high as 25 million feet squared per day. Yields of 2,000 gallons per minute from 12-inch wells are possible. Although the range in fluctuations of the potentiometric surface is as great as 20 feet, no significant change has occurred since the 1930's when data were first collected. The quality of water within the Floridan aquifer is generally excellent except near the Gulf Coast and in extreme east Marion County, near the St. Johns River where saltwater is present in the aquifer. Iron and hydrogen sulfide are sometimes a problem, but they can usually be con-trolled by proper well design and aeration of the water. Concentrations of sulfate do not exceed 250 milligrams per liter in the study area, and only in a small part of the area do dissolved-solids concentrations exceed 250 milligrams per liter. Summaries were compiled of more than 1,000 wells, 43 continuous-record gaging stations, 21 lakes, and 46 springs. The predominant chemical type for both streams and springs is calcium and magnesium bicarbonate due to the dissolution process of the carbonate rocks. Along the coastal areas and near the St. Johns River, water is commonly of the sodium chloride type. The majority of the streams have average dissolved-solids concentrations between 100 and 200 milligrams per liter, maximum-observed specific conductance between 250 and 750 micro-mhos per centimeter, and average total nitrogen concentrations of less than 1.2 milligrams per liter. Data for six lakes showed that the range of stage between the 90 and 10 percent exceedance stages is as great as 4.5 feet and as small as 2.2 feet. Little water-quality data for lakes are available, especially for the important constituents such as biochemical oxygen demand, total nitrogen, total phosphorus, and total carbon. Flow-duration data for springs show small ranges in discharge. The differences between the 10 and 90 percent exceedance discharges are 350 cubic feet per second for Silver Springs and 280 cubic feet per second for Rainbow Springs, the two largest springs in the area. Water quality of the springs is relatively constant with time because of the water's long residence time within the carbonate rocks.

Florida↗