GROUND WATER IN THE RARITAN RIVER BASIN A Technical Report for the Raritan Basin Watershed Management Project New Jersey Water Supply Authority Final Report: June 2002 II NJ Water Supply Authority JUNE 2002 III NJ Water Supply Authority JUNE 2002 GROUND WATER OF THE RARITAN RIVER BASIN TABLE OF CONTENTS ACKNOWLEDGEMENTS........................................................................................................................................VII SUMMARY................................................................................................................................................................... 1 Ground Water Recharge..............................................................................................................................................................1 Ground Water Contamination....................................................................................................................................................2 Septic System Capacity.................................................................................................................................................................2 HYDROLOGY.............................................................................................................................................................. 3 Definition of Ground Water.........................................................................................................................................................3 Concepts of Ground Water Flow and Recharge.......................................................................................................................3 Hydrology, Topography and Geography...................................................................................................................................4 Water Table vs. Confined Aquifer..............................................................................................................................................5 Karst ................................................................................................................................................................................................6 Basalt/Diabase ................................................................................................................................................................................6 “Age” of Ground Water ...............................................................................................................................................................6 RECHARGE AND USES............................................................................................................................................ 7 Definition of Recharge ..................................................................................................................................................................7 Ground Water Recharge in the Raritan Basin .........................................................................................................................7 Simulation of Ground Water Flows..........................................................................................................................................10 Adverse Effects of Impervious Cover and Soil Compaction Relative to Ground Water Recharge...............................12 Occurrences of Drought in the Basin........................................................................................................................................12 Ground Water Withdrawals......................................................................................................................................................13 Ground Water Discharges .........................................................................................................................................................13 PUBLIC USES........................................................................................................................................................... 14 Wells of the Basin.........................................................................................................................................................................14 Wellhead Protection Areas.........................................................................................................................................................14 WATER QUALITY..................................................................................................................................................... 16 Causes of Ground Water Contamination and Effects of Land Use on Ground Water Quality ....................................16 Known Contaminated Sites........................................................................................................................................................18 Contaminated Wells....................................................................................................................................................................19 Facilities Handling Solid Waste and Hazardous Materials...................................................................................................20 IV NJ Water Supply Authority JUNE 2002 ESTIMATING CARRYING CAPACITY FOR SEPTIC SYSTEMS........................................................................ 22 Geographic Area and Sub-areas ...............................................................................................................................................23 Purpose of Carrying Capacity Analysis...................................................................................................................................23 Assumption – Initial Nitrate Concentration in Ground Water............................................................................................23 Target Nitrate Concentration In Ground Water....................................................................................................................24 Assumption – Flow and Nitrate Loadings from Septic System............................................................................................25 Assumption – Nitrates from Other Sources ............................................................................................................................25 Approach to Estimating Ground Water Recharge ................................................................................................................25 General Limitations to Use of the Model .................................................................................................................................25 Limitations to Use of the Raritan Project Results ..................................................................................................................27 Results of the Septic System Carrying Capacity Analysis.....................................................................................................27 Comparison to Existing Septic Systems ...................................................................................................................................28 MANAGEMENT CONCLUSIONS OF EXISTING PLANS .................................................................................... 28 Existing and Proposed Regulations...........................................................................................................................................29 NJ State Development and Redevelopment Plan....................................................................................................................29 1989 Ground Water Strategy.....................................................................................................................................................30 NJDEP Wellhead Protection Program Plan ...........................................................................................................................30 South Branch Watershed Association Wellhead Protection Plan........................................................................................30 New Jersey Statewide Water Supply Plan...............................................................................................................................31 NJDEP Site Remediation Plan ..................................................................................................................................................31 CRITICAL NEEDS .................................................................................................................................................... 31 CONCLUSIONS ........................................................................................................................................................ 32 GLOSSARY OF TERMS .......................................................................................................................................... 33 COMMON ACRONYMS........................................................................................................................................... 34 REFERENCES .......................................................................................................................................................... 34 V NJ Water Supply Authority JUNE 2002 LIST OF TABLES Table 1 – Wellhead Protection Areas (WHPA) by Watershed Management Area (WMA)………………………15 Table 2 -- Known Contaminated Sites (KCSL) within Wellhead