Scientific Investigations Report 2008–5061

Prepared in cooperation with the New Jersey Pinelands Commission

Hydrogeologic framework in three drainage basins in the New Jersey Pinelands, 2004–06

By Richard L. Walker, Pamela A. Reilly, and Kara M. Watson

Scientific Investigations Report 2008–5061

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Abstract

The U.S. Geological Survey, in cooperation with the New Jersey Pinelands Commission, began a multi-phase hydrologic investigation in 2004 to characterize the hydrologic system supporting the aquatic and wetland communities of the New Jersey Pinelands area (Pinelands). The Pinelands is an ecologically diverse area in the southern New Jersey Coastal Plain underlain by the Kirkwood-Cohansey aquifer system. The demand for ground water from this aquifer system is increasing as local development increases. To assess the effects of ground-water withdrawals on Pinelands stream and wetland water levels, three drainage basins were selected for detailed hydrologic assessments, including the Albertson Brook, McDonalds Branch and the Morses Mill Stream basins. Study areas were defined surrounding the three drainage basins to provide sub-regional hydrogeologic data for the ground-water flow modeling phase of this study.

In the first phase of the hydrologic assessments, a database of hydrogeologic information and a hydrogeologic framework model for each of the three study areas were produced. These framework models, which illustrate typical hydrogeologic variations among different geographic subregions of the Pinelands, are the structural foundation for predictive ground-water flow models to be used in assessing the hydrologic effects of increased ground-water withdrawals.

During 2004–05, a hydrogeologic database was compiled using existing and new geophysical and lithologic data including suites of geophysical logs collected at 7 locations during the drilling of 21 wells and one deep boring within the three study areas. In addition, 27 miles of ground-penetrating radar (GPR) surface geophysical data were collected and analyzed to determine the depth and extent of shallow clays in the general vicinity of the streams. On the basis of these data, the Kirkwood-Cohansey aquifer system was divided into 7 layers to construct a hydrogeologic framework model for each study area. These layers are defined by their predominant sediment textures as aquifers and leaky confining layers. The confining layer at the base of the Kirkwood-Cohansey aquifer system, depending on location, is defined as one of two distinct clays of the Kirkwood Formation. The framework models are described using hydrogeologic sections, maps of structure tops of layers, and thickness maps showing variations of sediment textures of the various model layers. The three framework models are similar in structure but unique to their respective study areas.

The hydraulic conductivity of the Kirkwood-Cohansey aquifer system in the vicinity of the three study areas was determined from analysis of 16 slug tests and 136 well-performance tests. The mean values for hydraulic conductivity in the three study areas ranged from about 84 feet per day to 130 feet per day. With the exception of the basal confining layers, the variable and discontinuous nature of clay layers within the Kirkwood-Cohansey aquifer system was confirmed by the geophysical and lithologic records. Leaky confining layers and discontinuous clays are generally more common in the upper part of the aquifer system. Although the Kirkwood-Cohansey aquifer system generally has been considered a water-table aquifer in most areas, localized clays in the aquifer layers and the effectiveness of the leaky confining layers may act to impede the flow of ground water in varying amounts depending on the degree of confinement and the location, duration, and magnitude of the hydraulic stresses applied.

Considerable variability exists in the different sediment textures. The extent to which this hydrogeologic variability can be characterized is constrained by the extent of the available data. Thus, the hydraulic properties of the modeled layers were estimated on the basis of available horizontal hydraulic conductivity data and the range of sediment textures estimated from geophysical and lithologic data.


Contents

Abstract

Introduction

Purpose and Scope

Description of Study Areas

Hydrogeologic Setting

Previous Investigations

Methods of Investigation

Data Acquisition

Well-Numbering System

Altitude Data

Drilling Methods

Geophysical Methods

Borehole Geophysical Methods

Surface Geophysical Methods

Interpretive Methods

Database Compilation

Development of the Hydrogeologic Framework

Mapping Hydrogeologic Framework Layers

Hydrogeologic Sections

Determination of Aquifer System Properties

Slug-Test Methods

Slug-Test Analysis

Well-Performance Tests

Estimation of Spatial Variability of Aquifer System Properties

Hydrogeologic Framework

Hydrogeology of Albertson Brook Study Area and Vicinity

Hydrogeology of McDonalds Branch Study Area and Vicinity

Hydrogeology of Morses Mill Stream Study Area and Vicinity

Summary and Conclusions

Acknowledgments

References Cited

Appendix 1 Lithologic and geophysical logs of selected boreholes and newly installed wells in Kirkwood-Cohansey aquifer system, New Jersey Pineland

Appendix 2 Altitude, thickness, estimated sand content, and (or) horizontal hydraulic conductivity of hydrogeologic layers of the Kirkwood-Cohansey aquifer system, Albertson Brook study area and vicinity, New Jersey Pinelands

Appendix 3 Altitude, thickness, estimated sand content, and (or) horizontal hydraulic conductivity of hydrogeologic layers of the Kirkwood-Cohansey aquifer system, McDonalds Branch study area and vicinity, New Jersey Pinelands

Appendix 4 Altitude, thickness, estimated sand content, and (or) horizontal hydraulic conductivity of hydrogeologic layers of the Kirkwood-Cohansey aquifer system, Morses Mill Stream study area and vicinity, New Jersey Pinelands

Figures

1. Location of the Pinelands study areas, Atlantic, Burlington, and Camden Counties, New Jersey

2. (a) Generalized hydrogeologic section through the New Jersey Coastal Plain and (b) line of section

3–7. Maps showing—

3. Location of wells with horizontal hydraulic-conductivity data, Albertson Brook study area and vicinity, New Jersey Pinelands

4. Location of wells with horizontal hydraulic-conductivity data, McDonalds Branch study area and vicinity, New Jersey Pinelands

5. Location of wells with horizontal hydraulic-conductivity data, Morses Mill Stream study area and vicinity, New Jersey Pinelands

6. Location of boreholes, wells, and ground-penetrating radar (GPR) data points used to describe the hydrogeologic framework of the Albertson Brook study area and vicinity, New Jersey Pinelands

7. Location of hydrogeologic lines of section, and wells or boreholes with lithologic or geophysical data, Albertson Brook study area and vicinity, New Jersey Pinelands

8–11. Sections showing—

8. Hydrogeologic section A-A’, Albertson Brook study area and vicinity, New Jersey Pinelands

9. Hydrogeologic section B-B’, Albertson Brook study area and vicinity, New Jersey Pinelands

10. Hydrogeologic section C-C’, Albertson Brook study area and vicinity, New Jersey Pinelands

11. Hydrogeologic section D-D’, Albertson Brook study area and vicinity, New Jersey Pinelands

12–14. Maps showing—

12. Results of ground-penetrating radar (GPR) surveys used to describe the hydrogeologic framework of the Albertson Brook study area and vicinity, New Jersey Pinelands

13. Location of boreholes, wells, and ground-penetrating radar (GPR) data points used to describe the hydrogeologic framework of the McDonalds Branch study area and vicinity, New Jersey Pinelands

14. Location of hydrogeologic lines of section, and wells or boreholes with lithologic or geophysical data, McDonalds Branch study area and vicinity, New Jersey Pinelands

15–18. Sections showing—

15. Hydrogeologic section A-A’, McDonalds Branch study area and vicinity, New Jersey Pinelands

16. Hydrogeologic section B-B’, McDonalds Branch study area and vicinity, New Jersey Pinelands

17. Hydrogeologic section C-C’, McDonalds Branch study area and vicinity, New Jersey Pinelands

18. Hydrogeologic section D-D’, McDonalds Branch study area and vicinity, New Jersey Pinelands

19–21. Maps showing—

19. Results of ground-penetrating radar (GPR) surveys used to describe the hydrogeologic framework of the McDonalds Branch study area and vicinity, New Jersey Pinelands

20. Location of boreholes, wells, and ground-penetrating radar (GPR) data points used to describe the hydrogeologic framework of the Morses Mill Stream study area and vicinity, New Jersey Pinelands

21. Location of hydrogeologic lines of section, and wells or boreholes with lithologic or geophysical data, Morses Mill Stream study area and vicinity, New Jersey Pinelands

22–25. Sections showing—

22. Hydrogeologic section A-A’, Morses Mill Stream study area and vicinity, New Jersey Pinelands

23. Hydrogeologic section B-B’, Morses Mill Stream study area and vicinity, New Jersey Pinelands

24. Hydrogeologic section C-C’, Morses Mill Stream study area and vicinity, New Jersey Pinelands

25. Hydrogeologic section D-D’, Morses Mill Stream study area and vicinity, New Jersey Pinelands

26. Map showing Results of ground-penetrating radar (GPR) surveys used to describe the hydrogeologic framework of the Morses Mill Stream study area and vicinity, New Jersey Pinelands

Tables

1. Geologic and hydrogeologic units in the New Jersey Coastal Plain in New Jersey

2. Records of selected hydrologic investigation sites used to describe the hydrogeologic framework of the Kirkwood-Cohansey aquifer system in Pinelands study areas and vicinity, New Jersey

3. Estimated horizontal hydraulic conductivities and details of slug test for the 16 new wells installed in the Kirkwood-Cohansey aquifer system, Pinelands study areas, New Jersey

4. Estimated Hydraulic conductivity (K) values for sites in the Pinelands study areas and vicinity, New Jersey

5. Altitudes of tops of hydrogeologic layers of the Kirkwood-Cohansey aquifer system, Albertson Brook study area and vicinity, New Jersey Pinelands

6. Altitudes of tops of hydrogeologic layers of the Kirkwood-Cohansey aquifer system at selected wells in the McDonalds Branch study area and vicinity, New Jersey Pinelands

7. Altitudes of tops of hydrogeologic layers of the Kirkwood Cohansey aquifer system, Morses Mill study area and vicinity, New Jersey Pinelands


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