Geology topics

Frederick J. Spitz

Publications and source records attributed to Frederick J. Spitz.

8 recordsLinked to original sources

USGS2023

Simulation of flow and eutrophication in the central Salem River, New Jersey

The central Salem River in New Jersey is subject to periods of water-quality impairment, marked by elevated concentrations of phosphorus and chlorophyll- a , and low concentrations of and large diurnal swings in concentrations of dissolved oxygen. These seasonal eutrophic conditions are controlling factors for water quality in lower reaches, where the river is more lacustrine than in upper reaches, as a result of downstream damming. This biological productivity is supported by nutrient wash-off from agricultural areas in the surrounding watershed. To investigate this impairment, flow measurement and water-quality sampling were conducted during 2007–08 in support of development of a one-dimensional surface-water-quality model that simulates nutrient cycling and transformation processes. The U.S. Geological Survey, in cooperation with the New Jersey Department of Environmental Protection, used the U.S. Environmental Protection Agency Water Quality Analysis Simulation Program (WASP) to develop a receiving-water-quality model of the central Salem River between Woodstown and Deepwater, New Jersey, from April 2007 to October 2008. The main-stem river and largest tributary were simulated. In the flow model, kinematic wave flow is used to simulate flow in upper reaches and ponded weir flow is used to simulate flow in lower reaches. The water-quality model makes use of a mass-balance equation to simulate the fate and transport of nutrients, phytoplankton chlorophyll- a , dissolved oxygen, and oxygen demands (an indicator rather than a substance) in the river. Model input included channel characteristics, boundary conditions for flow and water quality, environmental parameters, vertical dispersion coefficients, settling rates, and kinetic constants. Inputs were estimated where field data were lacking, notably for tributary flows and nutrient loads. The model was calibrated to observed flow variables and concentrations of dissolved oxygen, chlorophyll- a , and nutrients at sampling locations, with emphasis on growing-season conditions. Calibration was achieved through graphical and statistical comparison of simulated results to observed data. Sensitivity analyses were performed, and model limitations and applicability were evaluated. Simulated results closely matched observed data in most cases, although some were overpredicted slightly. The most important causes of overprediction were estimated tributary flows for the flow model and estimated tributary watershed loads for the water-quality model. Calibration of dissolved-oxygen concentrations was closer, and predicted diurnal variations were consistent with high algal photosynthesis/respiration, although lack of continuous dissolved-oxygen data precluded verifying these predictions. A similar caveat applies to predicted diurnal variations in chlorophyll- a . Simulated limitations on algal growth were consistent with those based on observed data and indicated phosphorus was the main limiting nutrient, except during certain periods when nitrogen was limiting. Two water-quality management scenarios were simulated with the model to assess the effect of point- and nonpoint-source nutrient reductions on water-quality conditions in the river. Scenarios involved (1) a return of watershed land use to predevelopment natural conditions and (2) an extreme reduction in nutrient input. Although the extreme-nutrient-reduction scenario yielded improvements in water quality, the natural-conditions scenario yielded the largest improvements as indicated by minimal violations of surface-water-quality standards or thresholds. However, years may be needed to attain the full benefit of these management scenarios as a result of accumulation of phosphorus and organic carbon in riverbed sediments in lacustrine reaches. The results of this study indicate that the quality of water in the central Salem River will improve if management policies that mitigate the effects of nutrient-loading practices in the watershed, particularly those related to agriculture, are implemented.

New Jersey↗

USGS2017

Towards a comprehensive water quality modeling of Barnegat Bay: Development of ROMS to WASP Coupler

The Regional Ocean Modeling System (ROMS) has been coupled with the Water Quality Analysis Simulation Program (WASP) to be used in a comprehensive analysis of water quality in Barnegat Bay, New Jersey. The coupler can spatially aggregate hydrodynamic information in ROMS cells into larger WASP segments. It can also be used to resample ROMS output at a finer temporal scale to meet WASP time-stepping requirements. The coupler aggregates flow components, temperature, and salinity in ROMS output for input to WASP via a hydrodynamic linkage file. The coupler was tested initially with idealized cases designed to verify the water mass balance and conservation of constituent mass using one-to-one and one-to-many connectivity options between segments. A realistic example from the Toms River embayment, a subdomain of Barnegat Bay, was used to demonstrate the functionality of the coupling. A WASP eutrophication model accounting for dissolved oxygen (DO), nitrogen, and constant phytoplankton concentrations was applied to explore the distribution and trends in DO and nitrogen in the embayment for the period of July–August 2012. Results of DO modeling indicate satisfactory agreement with measurements collected at in-bay stations and also indicate that this coupled approach, despite substantial differences in spatiotemporal discretization between the models, provides adequate predictive capabilities.

New Jersey↗

USGS2009

Analysis of Effects of 2003 and Full-Allocation Withdrawals in Critical Area 1, East-Central New Jersey

Critical Area 1 in east-central New Jersey was mandated in the early 1980s to address large drawdowns caused by increases in groundwater withdrawals. The aquifers involved include the Englishtown aquifer system, Wenonah-Mount Laurel aquifer, and the Upper and Middle Potomac-Raritan-Magothy aquifers. Groundwater levels recovered as a result of mandated cutbacks in withdrawals that began in the late 1980s. Subsequent increased demand for water has necessitated an analysis to determine the effects of full-allocation withdrawals, which supplements an optimization analysis done previously. A steady-state regional groundwater flow model is used to evaluate the effects of 2003 withdrawals and full-allocation withdrawals (7.3 million gallons per day greater than for 2003) on simulated water-levels. Simulation results indicate that the range of available withdrawals greater than full-allocation withdrawals is likely between 0 and 12 million gallons per day. The estimated range of available withdrawals is based on: (1) an examination of hydraulic-heads resulting from each of the two simulations, (2) an examination of differences in heads between these two simulations, (3) a comparison of simulated heads from each of the two simulations with the estimated location of salty groundwater, and (4) a comparison of simulated 2003 water levels to observed 2003 water levels. The results of the simulations also indicate that obtaining most of the available water would require varying the distribution of withdrawals and (or) relaxing the mandated hydrologic constraints used to protect the water supply.

Open-File Report↗

USGS2008

Recovery of Ground-Water Levels From 1988 to 2003 and Analysis of Potential Water-Supply Management Options in Critical Area 1, East-Central New Jersey

Water levels in four confined aquifers in the New Jersey Coastal Plain within Water Supply Critical Area 1 have recovered as a result of reductions in ground-water withdrawals initiated by the State in the late 1980s. The aquifers are the Wenonah-Mount Laurel, the Upper and Middle Potomac-Raritan-Magothy, and Englishtown aquifer system. Because of increased water demand due to increased development in Monmouth, Ocean, and Middlesex Counties, five base and nine alternate management models were designed for the four aquifers to evaluate the effects resulting from potential reallocation of part of the Critical Area 1 reductions in withdrawals. The change in withdrawals and associated water-level changes in the aquifers for 1988-2003 are discussed. Generally, withdrawals decreased 25 to 30 Mgal/d (million gallons per day), and water levels increased 0 to 80 ft (feet). The Regional Aquifer-System Analysis (RASA) ground-water-flow model of the New Jersey Coastal Plain developed by the U.S. Geological Survey was used to simulate ground-water flow and optimize withdrawals using the Ground-Water Management Process (GWM) for MODFLOW. Results of the model were used to evaluate the effects of several possible water-supply management options in order to provide the information to water managers. The optimization method, which provides a means to set constraints that support mandated hydrologic conditions, then determine the maximum withdrawals that meet the constraints, is a more cost-effective approach than simulating a range of withdrawals to determine the effects on the aquifer system. The optimization method is particularly beneficial for a regional-scale study of this kind because of the large number of wells to be evaluated. Before the model was run, a buffer analysis was done to define an area with no additional withdrawals that minimizes changes in simulated streamflow in aquifer outcrop areas and simulated movement of ground water toward the wells from areas of possible high chloride concentrations in the northern and southern parts of the Critical Area. Five base water-supply management models were developed. Each management model has an objective function, decision variables, and constraints. Two of the five management models were test cases: clean slate option and reallocation from the Wenonah-Mount Laurel aquifer and Englishtown aquifer system to small volume wells for potable water use. Nine other models also were developed as part of a trade-off analysis between withdrawal amounts and constraint values. The 14 management models included current (2003) or regularly spaced well locations with variations on the constraints of ground-water head, drawdown, velocity at the 250-mg/L (milligram per liter) isochlor, and withdrawal rate. Results of each management model were evaluated in terms of withdrawals, heads, saltwater intrusion, and source of water by aquifer. Each trade-off curve was defined by using six to nine separate management model runs. Results of the management models designed in this study indicate that a withdrawal reallocation of 5 to 20 Mgal/d within Critical Area 1 would increase the area of heads below -30 ft and the velocity at the 250-mg/L isochlor by up to 4 times that of the simulated 2003 results; the range of values are 0 to 521 square miles and 1 to 20 feet per year, respectively. The increase in area of heads below -30 ft was larger in the Middle Potomac-Raritan-Magothy aquifer than in other aquifers because that area was negligible in 2003. The range of modeled withdrawals is closely tied to management-model design. Interpretation of management model results is provided as well as a discussion of limitations.

Scientific Investigations Report↗

USGS2008

Recovery of Ground-Water Levels from 1988 to 2003 and Analysis of Effects of 2003 and Full-Allocation Withdrawals in Critical Area 2, Southern New Jersey

Water levels in the Potomac-Raritan-Magothy aquifer system within Water Supply Critical Area 2 in the southern New Jersey Coastal Plain have recovered as a result of reductions in ground-water withdrawals initiated in the early 1990s. The Critical Area consists of the depleted zone and the threatened margin. The Potomac-Raritan-Magothy aquifer system consists of the Upper, Middle, and Lower aquifers. Generally, ground-water withdrawals from these aquifers declined 5 to 10 Mgal/d (million gallons per day) and water levels recovered 0 to 40 ft (foot) from 1988 to 2003. In order to reevaluate water-allocation restrictions in Critical Area 2 in response to changes in the ground-water-flow system and demands for additional water supply due to increased development, the New Jersey Department of Environmental Protection (NJDEP) needs information about the effects of changes in those allocations. Therefore, the U.S. Geological Survey (USGS), in cooperation with the NJDEP, used an existing ground-water-flow model of the New Jersey Coastal Plain to evaluate the effects of withdrawal alternatives on hydraulic heads in the Potomac-Raritan-Magothy aquifer system in Critical Area 2. The U.S. Geological Survey Regional Aquifer System Analysis model was used to simulate steady-state ground-water flow. Two withdrawal conditions were tested by using the model to evaluate hydraulic heads and differences in heads in these aquifers: 2003 withdrawals and full-allocation withdrawals (17.4 Mgal/d greater than 2003 withdrawals). Model results are presented using head maps and head-difference maps that compare 2003 to full-allocation withdrawals. Mandated hydrologic conditions for Critical Area protection are that the simulated -30-ft head contour not extend beyond the boundary of the depleted zone and (or) be at least 5 mi (miles) updip from the 250-mg/L (milligram per liter) isochlor in all three aquifers. Simulation results indicate that, for 2003 withdrawals, the simulated -30-ft head contour in all three aquifers is generally within the boundary of the depleted zone, except in the Lower aquifer in northern Camden and northwestern Burlington Counties, and is generally 1 to 10 mi downdip from the 250-mg/L isochlor. (Corresponding observed data indicate that the -30-ft water-level contour extends beyond the southwest boundary of the depleted zone in the Upper and Middle aquifers, and is generally 5 to 20 mi downdip from the 250-mg/L isochlor in all three aquifers.) The area in which heads are below -30 ft ranges from 389 mi2 (square miles) in the Middle aquifer to 427 mi2 in the Lower aquifer. For full-allocation withdrawals, the simulated -30-ft head contour extends beyond the boundary of the depleted zone in all three aquifers in northern Camden and northwestern Burlington Counties and in the Upper aquifer in Gloucester and Salem Counties, and is generally 5 to 15 mi downdip from the 250-mg/L isochlor. The area in which heads are below -30 ft ranges from 616 mi2 in the Upper aquifer to 813 mi2 in the Lower aquifer. These results and observed data indicate that any increase in withdrawals from 2003 values would likely cause heads in the three aquifers to decline below the minimum values mandated by the NJDEP for the Critical Area.

Scientific Investigations Report↗

USGS2007

Simulation of Surface-Water Conditions in the Nontidal Passaic River Basin, New Jersey

The Passaic River Basin, the third largest drainage basin in New Jersey, encompasses 950 mi2 (square miles) in the highly urbanized area outside New York City, with a population of 2 million. Water quality in the basin is affected by many natural and anthropogenic factors. Nutrient loading to the Wanaque Reservoir in the northern part of the basin is of particular concern and is caused partly by the diversion of water at two downstream intakes that is transferred back upstream to refill the reservoir. The larger of these diversions, Wanaque South intake, is on the lower Pompton River near Two Bridges, New Jersey. To support the development of a Total Maximum Daily Load (TMDL) for nutrients in the nontidal part of the basin (805 mi2), a water-quality transport model was needed. The U.S. Geological Survey, in cooperation with the New Jersey Department of Environmental Protection and New Jersey EcoComplex, developed a flow-routing model to provide the hydraulic inputs to the water-quality model. The Diffusion Analogy Flow model (DAFLOW) described herein was designed for integration with the Water Quality Analysis Simulation Program (WASP) watershed water-quality model. The flow routing model was used to simulate flow in 108 miles of the Passaic River and major tributaries. Flow data from U.S. Geological Survey streamflow-gaging stations represent most of the model's upstream boundaries. Other model inputs include estimated flows for ungaged tributaries and unchanneled drainage along the mainstem, and reported flows for major point-source discharges and diversions. The former flows were calibrated using the drainage-area ratio method. The simulation extended over a 4+ year period representing a range in flow conditions. Simulated channel cross-sectional geometry in the DAFLOW model was calibrated using several different approaches by adjusting area and top width parameters. The model also was calibrated to observed flows for water year 2001 (low flow) at five mainstem gaging stations and one station at which flow was estimated. The model's target range was medium to low flows--the range of typical intake operations. Simulated flow mass balance, hydrographs (flood-wave speed, attenuation, and spread), flow-duration curves, and velocity and depth values were compared to observed counterparts. Mass balance and hydrograph fit were evaluated quantitatively. Simulation results generally were within the accuracy of the flow data at the measurement stations. The model was validated to observed flows for water years 2000 (average flow), 2002 (extreme low flow), and 2003 (high flow). Results for 19 of 20 comparisons indicate average mass-balance and model-fit errors of 6.6 and 15.7 percent, respectively, indicating that the model reasonably represents the time variation of streamflow in the nontidal Passaic River Basin. An algorithm (subroutine) also was developed for DAFLOW to simulate the hydraulic mixing that occurs near the Wanaque South intake upstream from the confluence of the Pompton and Passaic Rivers. The intake draws water from multiple sources, including effluent from a nearby wastewater-treatment plant, all of which have different phosphorus loads. The algorithm determines the proportion of flow from each source and operates within a narrow flow range. The equations used in the algorithm are based on the theory of diffusion and lateral mixing in rivers. Parameters used in the equations were estimated from limited available local flow and water-quality data. As expected, simulation results for water years 2000, 2001, and 2003 indicate that most of the water drawn to the intake comes from the Pompton River; however, during many short periods of low flow and high diversion, particularly in water year 2002, entrainment of the other flow sources compensated for the insufficient flow in the Pompton River. As additional verification of the flow model used in the water-quality model, a Branched Lagrangian Transport Model (B

Scientific Investigations Report↗

USGS1998

Analysis of ground-water flow and saltwater encroachment in the shallow aquifer system of Cape May County, New Jersey

Cape May County, New Jersey, is on a natural peninsula that is virtually surrounded by saltwater. A calibrated quasi-three-dimensional sharp-interface model was used to simulate ground-water flow in the shallow aquifer system under two water-supply-development alternatives for a 30-year planning period. The alternatives involve modest increases in withdrawals in combination with desalination of brackish ground water or inland relocation of wells. Simulation results indicate that projected withdrawals for the two alternatives can be sustained without significant additional saltwater encroachment over the planning period.

Water Supply Paper↗

USGS1989

Simulation of ground-water flow in coastal southern New Jersey

An increasing trend of shallow ground-water withdrawal over the first part of this century on the Cape May Peninsula of New Jersey has resulted in the intrusion of saltwater into the aquifers that comprise the shallow ground-water system. The U.S. Geological Survey has developed a mathematical model of the flow system that simulates the flow regime at the freshwater-saltwater interface in the aquifers. The steady-state hydraulic-head distribution and interface position simulated by the model are in good agreement with those observed.

Conference Paper↗