1. 2New Jersey Department of Environmental Protection
Simulation of groundwater response to development: CENTRAL PASSAIC RIVER BASIN, NJ
Fatoumata Barry1,2, Duke Ophori1, Jeffrey L. Hoffman2 and Robert Canace2
1Department of Earth & Environment Studies, Montclair State University, Upper Montclair, NJ 07043
2New Jersey Department of Environmental Protection
P.O. Box 427, Trenton, NJ 08625

2. Issues Increased demand of water Decline of water levels
Due to population growth
Decline of water levels
Due to increase withdrawals
Decreased recharge
Due to urban development
Contamination
Have limited withdrawal in some areas

3. Objectives Develop a regional GW flow model to simulate:
flow paths
contaminants paths
contaminants source
protection areas around wells
Delineate regional discharge and recharge areas

4. Hackensack – Passaic River Basin
Study Area
Hackensack – Passaic River Basin

5. Model Design Conceptualization
SURFACIAL
Model Design Conceptualization
Sand and Gravel
LAYER 1
Silt, Clay
(Semi-confining Unit)
Sand and Gravel
(LAYER 2)
Layer 1
Layer 2
Layer 3
BEDROCK
(LAYER 3)
Sandstone, Siltstone
Basalt

6. Model Design - Boundaries
Lateral:
Western edge: Ramapo Fault (Granite on West side of fault)
Northern, Southern and Eastern edge: Crest of the 2nd Watchung Mountain
Vertical:
Top: Surface water Rivers, lakes, wetlands
Bottom: Bedrock

7. Data Input

8. Input Data Sets
Aquifer Parameters: specified for each grid cell within each layer
Hydraulic Conductivity
Transmissivity
Storage coefficients
Initial water levels
Botton and Top elevations
Vertical leakance to account for the hydraulic connection between adjacent layers.
Pumping Wells
Observation Wells
Recharge values
River Data

9. Flow Simulation
Modeling was done using the MODFLOW and MODPATH codes in the GMS package

10. Simulation Results

11. Steady State Calibration Surface and Heads of Unconfined Sand and Gravel comparison
Surface Elevation
Layer 1

12. 1990 Computed and Observed Water Level
Original
Calibrated

13. Interpretation

14. Prepumpage (1898) versus Recent (1995) Wetlands in unconfined sand and gravel

15. Unconfined Sand and Gravel Discharge Areas
1898
1995

16. Semi-confined Sand and Gravel Discharge Areas
1898
1995

17. Decline of Water Levels between 1898 and 1995

18. Hanover Twp - Heads and Flow vectors 1929 -1974

19. Hanover Twp - Heads and Flow vectors 1979 -1995

20. East Hanover, Parsippany Twps - Capture Zones Analysis

21. Conclusion Benefit from the model
Wetlands reduced from prepumping to pumping conditions
Discharge areas reduced after pumping started
Temporal flow patterns easily visualized
Decline of groundwater levels can be visualized
Analytical and Numerical Capture zones compared
Analytical capture zones found to be conservative

22. Questions and Comments Thank you