Hydrogeology and Simulation of Groundwater Flow in Fractured Rock in the Newark Basin, Rockland County, New York
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Prepared in cooperation with Rockland County, New York, and New York State Department of Environmental Conservation Hydrogeology and Simulation of Groundwater Flow in Fractured Rock in the Newark Basin, Rockland County, New York View toward northeast N Pascack Brook H H’ EXPLANATION More likely Capture zone—Shows Flow vector—Shows direction relative likelihood of recharge and relative magnitude of discharging at pumped well. groundwater flow. Less likely Scientific Investigations Report 2010–5250 U.S. Department of the Interior U.S. Geological Survey Cover. Three-dimensional perspective view of capture zone for Spring Valley well field in Rockland County NY, viewed to northeast parallel to strike of bedding. Hydrogeology and Simulation of Groundwater Flow in Fractured Rock in the Newark Basin, Rockland County, New York By Richard M. Yager and Nicholas M. Ratcliffe Prepared in cooperation with Rockland County, New York, and New York State Department of Environmental Conservation Scientific Investigations Report 2010–5250 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Marcia K. McNutt, Director U.S. Geological Survey, Reston, Virginia: 2010 For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 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Suggested citation: Yager, R.M., and Ratcliffe, N.M., 2010, Hydrogeology and simulation of groundwater flow in fractured rock in the Newark basin, Rockland County, New York: U.S. Geological Survey Scientific Investigations Report 2010–5250, 139 p. iii Contents Abstract ...........................................................................................................................................................1 Introduction.....................................................................................................................................................2 Purpose and Scope ..............................................................................................................................2 Previous Investigations........................................................................................................................4 Hydrogeology..................................................................................................................................................4 Bedrock Geology...................................................................................................................................4 Stratigraphy ..................................................................................................................................6 Structure........................................................................................................................................7 Surficial Geology .................................................................................................................................12 Hydrology .............................................................................................................................................12 Occurrence of Groundwater ....................................................................................................12 Groundwater Flow .....................................................................................................................12 Groundwater Discharge ...........................................................................................................16 Groundwater Withdrawals .......................................................................................................16 Transmissivity .............................................................................................................................20 Water-Bearing Zones ................................................................................................................20 Groundwater Flow Models .........................................................................................................................25 Spring Valley Well Field .....................................................................................................................25 Model Design..............................................................................................................................25 Mesh and Layering ...........................................................................................................25 Boundary Conditions ........................................................................................................27 Hydraulic Properties ........................................................................................................27 Model Calibration ......................................................................................................................27 Newark Basin Aquifer ........................................................................................................................29 Model Design..............................................................................................................................29 Mesh and Layering ...........................................................................................................29 Boundary Conditions ........................................................................................................33 Hydraulic Conductivity .....................................................................................................35 Model Calibration ......................................................................................................................38 Observations ......................................................................................................................38 Model Fit .............................................................................................................................38 Parameters ........................................................................................................................38 Comparison of Transmissivity Estimates .......................................................................44 Model Applications......................................................................................................................................47 Groundwater Age................................................................................................................................47 Capture Zones of Well Fields ............................................................................................................50 Transient Simulation of Changes in Recharge and Groundwater Withdrawals ......................51 Seasonal Transient Simulation: 2000 through 2003 ..............................................................56 Historical Transient Simulation: 1960 through 2006 ..............................................................58 Limitations and Additional Data Requirements .............................................................................58 Summary and Conclusions .........................................................................................................................61 Acknowledgments .......................................................................................................................................64 References Cited..........................................................................................................................................64 iv Appendix 1. Generalized bedrock geology of northern Newark basin ................................................68 Appendix 2. Modifications to SUTRA ................................................................................................ Link Appendix 3. Input data for the Time-Dependent Sources and Boundary Conditions Files (.bcs) ............................................................................................................................................. Link Appendix 4. Selected SUTRA Subroutines ...................................................................................... Link Figures 1. Map showing generalized bedrock stratigraphy and geographic features near Rockland County, NY, and extent of model domain .................................................................3 2. Graph showing population growth, 1940 through 2006, and annual groundwater use in Rockland County, NY, 1960 through 2006 .......................................................................4 3. Map showing well fields in operation in Rockland County, NY, and average groundwater withdrawals, 1995 through 2005 .........................................................................5 4. Generalized geologic sections showing sedimentary rock units and diabase intrusions in Newark basin, Rockland County, NY ..................................................................8 5. Shaded relief and aeromagnetic map of Rockland County, NY, and adjacent parts New Jersey and