Northwest New Jersey 15 Basin Aquifer
Hunterdon, Mercer, Middlesex, Morris, Passaic,
Somerset, Sussex, and Warren Counties New Jersey
- I. Introduction
- II. Hydrogeology
- III. Susceptibility to Contamination
- IV. Alternative Sources of Drinking Water
- V. Summary
- VI. Selected References
- VII. Tables
- Table 1. New Jersey Department of Environmental Conservation Sole Source Aquifer Designation Areas for Fifteen Basin Aquifer System
- Table 2. Percentage of Basin Aquifer Systems in Different Physiographic Provinces
- Table 3. Aquifer Service Area (ASA) Populations for the Fifteen Basin Aquifer Systems Service Area
- Table 4. Drinking Water Sources: Percentage of Drinking Water Supplied to ASA
- Table 5. Estimated Volume of Drinking Water Supplied
- Table 6. Potential Alternate Drinking Water Sources
- Table 7. Alternative Drinking Water Sources for Fifteen Basin Aquifer System
- VIII. Figures
The Safe Drinking Water Act (SDWA), Public Law 93-523, of December 16, 1974 contains a provision in Section 1424(e), which states that: "If the Administrator determines, on his own initiative or upon petition, that an area has an aquifer which is the sole or principal drinking water source for the area and which, if contaminated, would create significant hazard to public health, he shall publish notice of that determination in the Federal Register. After the publication of any such notice, no commitment for Federal financial assistance (through a grant, contract, loan guarantee, or otherwise) may be entered into for any project which the Administrator determines may contaminate such aquifer through a recharge zone so as to create a significant hazard to public health, but a commitment for Federal financial assistance may, if authorized under another provision of law, be entered into to plan or design the project to assure that it will not so contaminate the aquifer."
This section allows for the specific designation of areas which are dependent upon ground water supplies. Following designation, the review process will ensure that federal agencies will not commit funds toward projects which may contaminate these ground water supplies.
On November 18, 1985 the New Jersey Department of Environmental Protection (NJDEP) petitioned the U.S. Environmental Protection Agency (EPA) Administrator to declare the aquifer systems of the Coastal Plain, Piedmont, Highlands, and Valley and Ridge Physiographic Provinces, as defined in the petition, a sole source aquifer (SSA) under the provisions of the SDWA.
The area specified in the petition submitted by NJDEP included the entire State of New Jersey, except for the City of Trenton within the Coastal Plain and Piedmont Provinces in westcentral New Jersey, and sixty-nine (69) communities within the Piedmont Province in northeast New Jersey (Figure 1).
In December 1986, a meeting between EPA and NJDEP representatives was held to discuss the State's petition. At the meeting EPA explained that other petitions had been received prior to the State's petition, and that it is Agency policy to process petitions in the order they are received. In addition, EPA informed NJDEP of the new guidelines for the SSA designation process. Since their petition was submitted before the new guidelines took effect, they did not have to conform to them. However, it was stated that due to the complexity of the State's petition, NJDEP cooperation in providing EPA with materials and justification in accordance with the new guidelines would facilitate the processing the petition prior to the June 19, 1988 designation deadline for SSA Demonstration Program eligibility.
In February 1987, EPA provided NJDEP with completeness review comments stating the petition did not: (1) identify the portions of the Piedmont, Highlands, and Valley and Ridge Provinces which extend into New York State or show that formations between New Jersey and New York are not hydraulically connected; (2) substantiate the statement that there are no alternative water sources; (3) identify the public water systems utilizing the aquifer systems, the number of people served by each system, and the type of treatment provided; and (4) demonstrate that the areas of New Jersey excluded from the petition are not part of the petitioned aquifer systems.
In June 1987, based on the comments summarized above and the fact that several portions of the State had been designated or petitioned for designation as SSAs, NJDEP began to revise the petition. The revised petition only addresses areas which were not designated or petitioned for designation, and uses a drainage basin approach to define boundaries of the aquifer systems. The rationale for using a drainage basin approach is explained in the Hydrology section of this document.
EPA entered into an Interagency Agreement (total project cost of $25,000) with the U.S. Geological Survey, Division of Water Resources, New Jersey District Office in July, 1987. The agreement called for the U.S. Geological Survey to provide technical support to EPA during the petition revision and review process.
Initially twenty-one (21) basin aquifer systems were to be included in the revised petition. However, the NJDEP determined that four of these were not eligible for SSA designation because of an insufficient ground water dependency. NJDEP developed the documentation for the remaining seventeen (17) basin aquifer systems. Subsequently, EPA determined that the NJDEP's ground water use methodology did not consider the entire aquifer service area populations. NJDEP revised the ground water use characterization to consider the entire aquifer service area, and another basin aquifer system was determined to be ineligible for SSA designation because of an insufficient ground water dependency. This reduced the number of basin aquifer systems under consideration to sixteen (16). In addition, EPA found that another basin aquifer system had been previously designated as part of the Buried Valley SSA. Therefore, the area of consideration for this designation support document is limited to the fifteen (15) basin aquifer systems in the NJDEP Revised Petition.
The total area encompassed by the Fifteen (15) Basin Aquifer Systems is approximately 1,735 square miles Figure 2. The names of each basin aquifer system corresponds to the name of a stream within that aquifer system's designated area. Boundaries of the aquifer systems are defined by drainage basin divides, streams which serve as discharge points, and the northern boundary of the Coastal Plain where it crosses the Millstone River Basin. The portion of the Millstone River Basin within the Coastal Plain is being considered with the rest of that physiographic province in a separate petition. The Delaware River, a major discharge point for several of the basin aquifer systems, constitutes the western boundary of the petition area. The aquifer systems under consideration, and the counties and municipalities which overlie them are identified in Table 1.
The topography of the area is quite variable with elevations ranging from approximately one hundred-fifty to one hundred-eighty feet (150 - 180') above sea level. The entire area is characterized by northeastsouthwest trending hills and valleys (Parker, 1964; Lucey, 1975).
The eastern and northern portion of the Piedmont Physiographic Province in the area is marked by rounded hills separated by broad valleys. The hills increase in size moving west from the Fall Line. The Hunterdon Plateau, with an average elevation of five-hundred to five-hundred fifty feet (500-550') above sea level, occupies much of the western portion of the province in the area (Vecchioli and Palmer, 1962; and Kasabach, 1966).
The Highlands Physiographic Province rises abruptly to the west of the Piedmont. The province consists of a series of ridges and narrow deep Valleys. The average elevation of the ridges is eight-hundred to one-thousand feet (800-1,000') above sea level (Kasahach, 1966).
Topography of the Valley and Ridge Physiographic Province is dominated by Kittatinny Mountain and the associated valleys, High Point (1802.5 feet above mean sea level) is the highest point in New Jersey and is located on the northwest portion of Kittatinny Mountain. Kittatinny Mountain is approximately forty (40) miles long and from one to five (1 - 5) miles wide (Lucey, 1975).
The petition area is characterized by a modified continental climate. Although the Atlantic ocean is only approximately forty miles (40 mi.) away, prevailing offshore winds significantly reduce the tempering effect of the ocean (Kasabach, 1966).
Average precipitation ranges from forty-two to fifty-one (42 - 51) inches per year and is evenly distributed throughout the year. The average temperature ranges from the upper sixties to low seventies in summer and from the midtwenties to low thirties in winter (NJDEP, 1985; Carswell and Rooney, 1976; Veccnioli and Palmer, 1962).
The area encompassed by the basin aquifer systems includes portions of the Valley and Ridge, Highlands and Piedmont Physiographic Provinces. Table 2 lists the aquifer systems by physiographic province with the percentage of each aquifer system in that province. This section briefly summarizes the geology for the portions of provinces included in the petitioned area.
The portion of the Piedmont province within the petition area is comprised primarily of Jurassic and Triassic age sedimentary rocks and igneous rocks and to a lesser extent unconsolidated Quaternary glacial deposits. The sedimentary rocks consist of shale, argillite, and sandstones of the Newark Supergroup, and are commonly divided into the Brunswick Group, and the Stockton and Lockatong Formations. Along the northwest border of the Piedmont, some of the Brunswick Group formations grade into beds of conglomerate (Lyttle and Epstein, 1987). The Newark Supergroup forms a monocline with a northeasterly strike and a shallow dip (typically between 1020 degrees) to the northwest (NJDEP, 1985; Widmer 1965).
Diabase intrusives of Jurassic and Triassic age form the predominant igneous rock type in the Piedmont portion of the petition area. Diabase intrusives are resistant to weathering and form topographic highs (Kasabach, 1966).
Two major faults, the Hopewell and Flemington Faults, cause repetition of the Jurassic and Triassic strata in the petition area. Associated with both faults are several relatively small diabase intrusives (Kasabach, 1966). Vertical or steeply dipping joints occur in the Jurassic and Triassic rocks. The major joint sets are parallel and transverse to the strike of the beds (Carswell and Rooney, 1976).
All the formations in the Piedmont portion of the petition area contain little primary (intergranular) porosity and therefore transmit water through secondary openings along cleavage planes, joints, fractures, and faults (NJDEP 1985, Carswell and Rooney, 1976; Vechiolli and Palmer, 1962). Due to increasing pressure, openings decrease in size and number with depth until there is no appreciable flow. Fracture closure has been documented in the Brunswick at depths between three-hundred to four-hundred feet (300-400') (NJDEP, 1987).
The entire portion of the Piedmont province within the area of consideration is south of the Wisconsian Terminal Moraine. Glacial deposits south of the Terminal Moraine are relatively thin (less than 100 feet thick), discontinuous, and of minor significance as aquifers. Thindeposits of recent alluvium overlie some of the outwash deposits or lie directly on bedrock (Vecchioli and Palmer, 1962; Kasabach, 1966).
Commonly referred to as the Highlands, this province is a northeast trending belt of rocks which covers approximately 908 square miles in northwest New Jersey. The Highlands is located between the Piedmont and Valley and Ridge Provinces.
The portion of the Highlands province within the petition area is characterized by Precambrian gneiss, intrusive rocks, and a synclinal outlier of Paleozoic sedimentary strata which exhibits geology similar to that of the Valley and Ridge Province.
Ridges are comprised of igneous and metamorphic rocks while valleys are underlain by less resistant limestones and shales. The alignment of the ridges and valleys is parallel to the northeast strike of the layers and foliations of the sedimentary, igneous, and metamorphic rocks, and the parallel trends of fold axis and major faults. Vertical or steeply dipping joints are oriented parallel, transverse, and oblique to the regional structure (Kasabach, 1966; Carswell and Rooney, 1976).
All the formations in the Highlands transmit water due to secondary openings. Specific members of the Kittatinny Limestone contain solution cavities which permit conduit flow. Measurements indicate that fracture closure occurs within three-hundred feet (300') of the surface in the Highlands (NJDEP, 1987).
Quaternary glacial deposits occur over much of the Highlands area north of the Terminal Moraine which, extends from Morristown to Belvidere. Upland areas are covered by a thin veneer of till, usually less than twenty feet (20') thick. Valleys can be filled with as much as three hundred-fifty feet (350') of stratified drift deposits (NJDEP, 1985).
The Valley and Ridge Province in New Jersey encompasses the northwest 576 square miles of the State. The entire area of the province in New Jersey, and a small extension of the province into New York is included in the petition area.
The geology of the Valley and Ridge province is characterized by Paleozoic sedimentary rocks which form a series of ridges and valleys. Resistant shales and sandstones form the ridges and less resistant carbonate rocks form the valleys (NJDEP, 1985).
ALL the formations transmit water due to secondary openings. Specific members of the Kittatinny Formation contain solution cavities which permit conduit flow (NJDEP, 1985). Measurements indicate that fracture closure generally occurs at depths less than two-hundred feet (200') in the Valley and Ridge province (NJDEP, 1987).
Quaternary glacial deposits occur over most of the Valley and Ridge Province The entire province, except for the extreme southeastern portion, is north of the Terminal Moraine. Upland areas are covered by a thin veneer of till, usually less than twenty feet (20') thick. Valleys can be filled with as much as three-hundred fifty feet (350') of stratified drift deposits (NJDEP, 1985).
The aquifer systems in northwest New Jersey have been defined using a surface water drainage basin approach. This is based on hydrogeologic theory and studies which indicate that regional and intermediate ground water flow systems are not present throughout most of the area.
The factors influencing development of ground water flow systems include topographic relief, climate, the mechanism of flow (primary or secondary openings), and the basin depthtowidth ratio. The basin depthtowidth ratio is a measurement of the subsurface flow basin. Shallow basins (depth to width ratio of 0.05 or less) in a humid region with well defined topographic relief normally only develop local flow systems (Fetter, 1980).
Given the extent of topographic relief, humid climate, and that depthtowidth ratios for the majority of the basin aquifer systems are considerably less than 0.05, local flow systems predominate in northwest New Jersey. Exceptions to this include the Shimmers Brook, Van Campens Brook, Delawanna Creek, and Lopatcong Creek Basin Aquifer Systems; all located alongside the Delaware River. These basin aquifer systems are actually groupings of the small watershed areas adjacent to the Delaware. These watersheds were grouped to form four basin aquifer systems because topographic divisions between them are less distinct and their depth-to-width ratios are larger than for watersheds in other portions of the petition area. The boundaries of these basin aquifer systems are the drainage basin divides of the larger tributaries' basin aquifer systems also considered in this petition (i.e., Flat Brook, Pequest River, Musconetconq River and Paulins Kill).
Although geologic formations which comprise the aquifer systems in the petition area are regional in extent, the aquifer systems themselves are defined by drainage basin boundaries and streams which serve as discharge points for the flow systems (NJDEP, 1988).
The water table in the area occurs at depths twenty to forty feet (20 - 40') feet below the land surface on the hilltops and intersects the land surface in valleys. It is coincident with the upper surface of streams, lakes, and swamps (Carswell and Rooney, 1976).
Recharge in this area is almost entirely from precipitation within the basins. There are no studies which precisely define recharge areas for the aquifer systems. However, local flow systems typically are recharged at topo-graphic high areas and discharge at adjacent topographic low areas (Fetter, 1980). Therefore, it is likely that recharge occurs over tne entire petition area, excluding discharge areas (NJDEP, 1985). The rate of recharge is probably greater where glacial till is thin or discontinuous and weathered bedrock is exposed, or sand and gravel deposits are at the surface.
The direction of ground water flow is generally down and toward the river valleys in the uplands, and up and toward the streams in the valley bottoms. The ground water discharges from the aquifer system by seepage into streams, lakes and swamps, by evapotranspiration, and by flow to pumping wells.
Quaternary stratified drift deposits in the area are predominantly shallow (less than 100 feet) and tend to provide water storage for recharging underlying bedrock, or small community and domestic supplies. There are twenty-four (24) stratified drift deposits, such as those in the Wallkill and Whippany River Basins, of considerably greater thickness. Sands and gravels within these deposits can be very productive (Harper, unpublished; NJDEP, 1985). Ground water flow through all glacial deposits in the area is considered confincd to the minor basins in which the deposits occur (NJDEP, 1987).
The ambient ground water quality within the petition area varies considerably, although for the most part is suitable for drinking following disinfection treatment. Variations are attributed mainly to (1) differences in the composition of the rocks, (2) the pattern of ground water movement from recharge to discharge, and (3) the length of time that the water is in contact with the various rock types.
All water purveyors in New Jersey are required to report the type of treatment they provide prior to delivering water to their customers. Approximately eithty-one percent (81%) of the purveyors within the petition area provide no treatment or provide disinfection only (NJDEP, 1988). Since purveyors must monitor their supplies to ensure they meet Federal and State standards, an absence of treatment indicates ambient ground water quality exceeds such standards. However, localized contamination has resulted in numerous well closings in the petition area.
The proposed SSA designation areas for the Fifteen Basin Aquifer Systems are defined as the glacial deposits and bedrock within the areas illustrated in Figure 3. The aquifer service area (SSA) extends slightly beyond the designated areas for ten of the aquifer systems. The aquifer system boundary lines and extensions of the ASAs beyond them were delineated by U.S. Geological Survey Water Resources Division, New Jersey District personnel on topographic quadrangle sheets (1;24,000). The lines were then digitized by USGS personnel directly from the quadrangle sheets.
The recharge areas are identical to the SSA designation areas. All precipitation within these boundaries has the possibility of recharging the aquifer systems.
The streamflow source zone is defined as the upstream area of losing streams which flow into the recharge area. There are no streams flowing into the recharge area except for the Millstone River, and all measurements indicate that streams in the area are gaining streams. Therefore, there is no streamflow source zone. Because of this, the project review area is coincident with the designated aquifer areas.
Ground water use in the SSAs for each of the Fifteen Basin Aquifer Systems is characterized in the NJDEP Revised Petition. As indicated, each aquifer system supplies more than fifty percent (50%) of the drinking water for its aquifer service area. This section Summarizes the results of the ground water use characterization.
Table 3 shows the population of the SSAs for each of the basin aquifer systems and the number of people dependent on each basin aquifer system for drinking water. The population dependent on each basin aquifer system is further categorized as relying on public water systems or domestic wells.
Table 4 depicts the percentage of drinking water supplied to each SSA from: (1) its associated aquifer system; (2) surface water sources within its basin aquifer system; and (3) sources outside the basin aquifer system. Each of the ASAs receive more than fifty percent (50%) of their drinking water from their associated basin aquifer system.
The estimated daily volume of water supplied by each basin aquifer system is presented in Table 5. The total volume supplied by the Fifteen Basin Aquifer Systems is approximately 49.3 million gallons per day (mgd). The estimated volumes assume an average water usage of one-hundred gallons per day (100 gpd) per person. This figure was obtained from EPA's Region II Drinking/Ground Water Protection Branch and corresponds to the design criteria for public water systems in New Jersey.
Documentation submitted by NJDEP assumed an average usage of seventy-five gallons per day (75 gpd) per person. This figure is used by USGS water use personnel for estimating water use by individuals relying on domestic wells.
Review of documentation from previous SSA designations by Region II shows that the one-hundred gallons per day (100 gpd) per person figure has been used. The one-hundred gallon per day figure more accurately represents the total residential, recreational, commercial and industrial drinking water use in the area. It also accounts for losses inherent in any distribution system. Furthermore, if the aquifer systems were to become contaminated, public water systems would be needed to replace them. Such systems would need to have sufficient water supplies to satisfy the one-hundred gallon per person design criteria.
The Fifteen Basin Aquifer Systems of northwest New Jersey are vulnerable to contamination from many sources. The thinness of the soils, the high permeability of the stratified glacial deposits, and the fractured nature of the bedrock contribute to the vulnerability and spread of contamination. This problem is complicated by the fact that bedrock wells in the area penetrate more than one waterproducing zone having different hydraulic heads. This causes the disruption of natural flow and swifter spread of contamination (Carswell and Rooney, 1976).
The following is a discussion of potential sources of contamination, many of which receive federal financial assistance through agencies such as the Federal Highway Administration, Department of Housing and Urban Development and EPA. Documentation submitted by NJDEP in support of their petition) quantifies potential sources of contamination in each of the aquifer systems.
Transportation Routes and Facilities
Several highways, many county routes, and railroads pass through the proposed designation areas. The potential exists for an accidental spill on the land overlying the aquifer systems which could result in serious and direct contamination of the ground water supply. Tons of petroleum products and industrial and agricultural chemicals are carried through and used in the area each year. Several counties and municipalities are recipients of Federal Department of Transportation grants.
On Site Septic Disposal
Most development depends upon onsite septic systems. These systems, depending on design and soil conditions, may lead to contamination of the ground water system. The petition provided a number of domestic and community septic systems for each aquifer system.
Storm Water Run-off
Runoff may contain various potential contaminants that can enter the aquifer system. These include deicing salts, animal excrement, pesticides, fertilizers, petroleum products, bacteria, and particulates from air pollutants.
Commercial and Industrial Facilities
There are various commercial and industrial facilities located within the aquifer boundaries. These facilities use or store chemicals and substances that could be hazardous if allowed to enter the ground water system. Common examples are underground tanks for the storage of heating oil and gasoline, and surface impoundments at treatment plants or other facilities. Leakage and/or accidental spills from the storage tanks and impoundments is a potential source of ground water contamination.
The NJDEP Petition identifies the number of gasoline service stations (an indicator of underground storage tanks), surface impoundments, and New Jersey Pollution Elimination System discharges in each aquifer system. All of the aquifer systems contain commercial or industrial facilities which are a potential source of contamination.
Future commercial, industrial, and residential development is also a potential source of contamination to the aquifer systems. Population projections for the year 2000 indicate development in the basin aquifer systems will be increasing in the future. Therefore, projects should be designed to avoid significant increases in contaminant loading to the aquifer systems.
There are no alternate sources with existing infrastructure which can provide the same quantity of water as the Fifteen Basin Aquifer Systems. Potential alternate sources are listed in Table 6. Those sources marked with an asterisk have constraints which prohibit their use. Constraints include the lack of sufficient supply, infrastructure, permits, or contracts required to allow their use as alternative sources for the Fifteen Basin Aquifer System area. Constraints on each source eliminated are explained in the documentation submitted by NJDEP in support of their petition.
The remaining sources include Spruce Run and Round Valley Reservoirs, the Delaware and Raritan Canal, and the Lawrence Chain of Lakes. Table 7 shows the yield, current allotment, and surplus for each source. The total daily supply available from the three sources combined is approximately 41.6 million gallons per day.
A comparison of Tables 5 and 7 shows that the total daily volume available from alternative drinking water sources is insufficient to replace that supplied by the Fifteen Basin Aquifer Systems, a total of approximately 49.3 million gallons per day.
Even if alternate sources could supply a sufficient volume of water, interconnections are not sufficient to deliver these alternate supplies to many purveyors in the basin aquifer systems. Furthermore, water distribution systems would need to be constructed to supply approximately 275,000 people who are on domestic wells throughout the 1,735 square mile area. Construction of the necessary interconnections between purveyors in different basins and water distribution systems to those currently relying on domestic wells would require a tremendous capital investment. The rugged topography and hard rock geology of northwest New Jersey would also make such construction extremely difficult.
Based on the above discussion, it is concluded that there are no alternate drinking water supplies which can replace the Fifteen Basin Aquifer Systems at a reasonable cost.
Based upon the information presented, the Fifteen Basin Aquifer Systems of northwest New Jersey, as defined in this document, meet the technical requirements for SSA designation. More than fifty percent (50%) of the drinking water for the aquifer service areas is supplied by the aquifer system. In addition, there are no economically feasible alternative drinking water sources which could replace the aquifer systems. Therefore, it is recommended that the Fifteen Basin Aquifer Systems listed in Table 1 be designated a Sole Source Aquifer. This will provide an additional review of ground water protection measures, incorporating state and local measures whenever possible, for only those projects which request Federal financial assistance.
1. Carswell, L.D. and Rooney, J.G., 1976, Summary of Geology and Ground Water Resources of Passaic County, New Jersey, U.S. Geological Survey, Water Resources Investigations 7675.
2. Fetter, C.W., 1980, Applied Hydrogeology, Ohio, Charles E. Merrill.
3. Kasahach, H.F., 1966, Geology and Ground Water Resources of Hunterdon County, New Jersey, New Jersey Department of Conservation and Economic Development, Division of Water Policy and Supply, Trenton, New Jersey.
4. Lucey, C.S., 1975, The Geology of Sussex County in Brief, New Jersey Department of Conservation and Economic Development, Bureau of Geology and Topography.
5. Lyttle and Epstein, 187, Geologic Map of the Newark 1 x 2 Quadrangle, Map I1715, Miscellaneous Investigation Series, U.S. Geological Survey.
6. New Jersey Department of Environmental Protection, 1985, Sole Source Aquifer Petition.
7. New Jersey Department of Environmental Protection, 1987, Sole Source Aquifer Petition Technical/Background Documentation, Petition, Recharge, and Streamflow Source Zone Areas.
8. New Jersey Department of Environmental Protection, 1988, Sole Source Aquifer Petition Technical/Background Documentation, Package Two.
9. New Jersey Department of Environmental Protection, 1988, Sole Source Aquifer Petition Technical/Background Documentation, Package Three.
10. New Jersey Department of Environmental Protection, 1988, Sole Source Aquifer Petition Technical/Background Documentation, Package Four.
11. Parker, G.C., Hely, A.G., Keighton, W.B., and Olmstead, F.H., 1964, Water Resources of the Delaware River Basin, U.S. Geological Survey Professional Paper 381.
12. Vecchioli, J. and Palmer, M.M., 1962, Ground Water Resources of Mercer County, New Jersey Department of Conservation and Economic Development, Division of Water Policy and Supply.
13. Widmer, K., 1964, Geology of the Ground Water Resources of Mercer County, New Jersey Department of Conservation and Economic Development, Bureau of Geology and Topography.