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Water > Aquifers > Rockaway River Area Aquifer System ( Unconsolidated Quaternary )

Rockaway River Area Aquifer System ( Unconsolidated Quaternary )

Support Document Morris County New Jersey December 1983

I. Introduction

• A. Statement of Section 1424(e)
• B. Receipt of Petition
• C. Area of Consideration
• D. Climate

II. Hydrogeology

• A. Geologic Framework
• B. Geologic Setting
• C. Ground Water Hydrology
  • 1. Recharge
  • 2. Streamflow Source Zone
• D. Ground Water Use

III. Ground Water Sources

• A. Exchange Between River and Aquifers
• B. Quaternary Formations
• C. Precambrian Formations
• D. Paleozoic Formations
• E. Triassic Formations

IV. Susceptibility to Conamination

V. Alternative Sources of Drinking Water

VI. Summary

VII. Selected References

VII. Tables

• Table 1. Stratigraphic Section in Morris County, New Jersey
• Table 2. Estimated Safe Yield by Geologic Formation
• Table 3. Population of Towns

VIII. Figures

• Figure 1. Unconsolidated Quaternary Aquifer System Designated Area (Upper River Basin Area)
• Figure 2. Location of Rockaway River Drainage Basin in Morris County
• Figure 3. Generalized Geologic Map of Rockaway River Region
• Figure 4. Geologic Cross Sections of Bedrock Formations
• Figure 5. Detailed Quaternary Geology of Morris County
• Figure 6. Hypothetical Cross-Section to Illustrate Confined and Unconfined Aquifers
• Figure 7. Public and Private Well Locations in the Rockaway River Drainage Basin
• Figure 8. The Recharge and Streamflow Source Zones in the Rockaway River Basin

I. Introduction

A. Statement of Section 1424 (e)

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.

B. Receipt of Petition

On November 30, 1979, the Upper Rockaway Watershed Association, the Administrator of the U.S. Environmental Protection Agency (EPA) to designate the "Quaternary Wisconsin stratified drift deposits in the Upper Rockaway River Basin municipalities as a sole source aquifer or principal source aquifer ..." under the provisions of the Safe Drinking Water Act.

A notice of receipt of this petition, together with a request for comments, was published in the Federal Register (45 FR 60010) Thursday, September 11, 1980.

C. Area of Consideration

The boundary of the area of consideration underlain by the Quaternary deposits, includes thirteen municipalities in Morris County, New Jersey, which lie within the Rockaway River drainage basin. These municipalities are the following: 1) Town of Boonton, 2) Boonton Township, 3) Denville, 4) Dover, 5)Jefferson Township, 6) Mine Hill, 7) Mountain Lakes, 8) Randolph Township, 9) Rockaway Borough, 10) Rockaway Township, 11) Roxbury, 12) Victory Gardens and 13) Wharton. The total population of this area is approximately 135,000 (1980) with an estimated potable water usage of 12 million gallons per day (MGD).

Public water supply systems drawing from the unconsolidated Quaternary deposits supply an estimated 90,000 persons within these thirteen municipalities. Within the Rockaway River drainage basin, individual wells drawing from the unconsolidated aquifer deposits, as well as bedrock aquifers, supply an estimated 30,000 persons with 2.7 MGD. The Unconsolidated Quaternary Aquifer supplies greater than seventy-five percent (75%) of the potable water in the designated area.

In 1976, approximately 9.5 MGD was withdrawn for public supply from the Unconsolidated Quaternary Aquifer. In addition to supplying potable water to the area's population, the aquifer is an important source of streamflow to the Rockaway River system which drains into the Boonton Reservoir and the Passaic River. Four municipalities in Hudson, Essex and Bergen counties, with a population of 297,725 (1980), are served by the Boonton reservoir facility. In addition, the Passaic Valley Water Commission withdraws 75 MGD from the Passaic River to service a population of 287,000 with drinking water.

D. Climate

The service area has a continental climate with moderately cold winters and hot wet summers. Snow can be expected between November and April. The first frost usually falls between September 30th and October 10th and the last frost between May 5th and May 10th (EAC, 1977). The average growing season is l65 days.

Precipitation is distributed fairly evenly throughout the year averaging three to five inches per month. Abnormally high amounts have occurred in hurricanes. Average annual precipitation at the Boonton station was 42.97 inches for the period l93ll973 (EAC, 1977). During the drought between 1961 and 1966 the average annual rainfall was 37.4 inches at the Boonton station (Jersey City Water Co.), a decrease of thirteen percent (13%) from the long-term average. In the worst year of the drought, 1965, the precipitation was only 29.2 inches. The drought index is based on precipitation, temperature and antecedent moisture conditions, and is abetter indicator of drought conditions than sole precipitation (Havens, 1966). A recent study relating tree rings to precipitation and the Palmer Drought Index found the 1961-1966 drought to be the most severe between 1730 and 1970 (Cook and Jacoby, 1977).

Evapotranspiration includes loss of water from evaporation of surface water, direct evaporation of ground water when the water table is high, and use by plants of water contained in the soil. It is greatest in the summer because of the high temperatures. Estimated actual evapotranspiration for the drought years of 1961-1966 is twenty inches (20") which agrees with the estimate by Hely (EAC, 1977) of twenty to twenty-two inches (20 - 22") per year. Recharge to the ground water can occur only when precipitation exceeds evapotranspiration and the soil moisture deficit has been satisfied.

II. Hydrogeology

A. Geologic Framework

The rock formations of the region can be divided into two broad groups: older, consolidated bedrock formations and younger, unconsolidated glacial deposits. A generalized geologic map shows the location of the different bedrock formations. The Stratigraphic section exposed in the area is described in Table 1. A geologic cross section across northern Morris County (A to A ) shows that the Paleozoic rocks are in a syncline exposed by faulting which is underlain by Precambrian rocks. The bedrock formations are grouped into Precambrian gneiss, Paleozoic formations, and Triassic formations. The Paleozoic rocks of predominantly Silurian and Devonian age outcrop in a narrow band one to four miles (1 - 4 mi.) miles in width trending northeast-southwest. Triassic formations of the Newark Group and basalt underlie the Piedmont province. Part of the water supply of Montville comes from the Triassic formations.

The glacial geology is shown, the map shows the location of deposits and wells obtaining water from Quaternary formations (Gill and Vecchioli, 1965). It appears to have been a somewhat arbitrary distinction as it does not include all the wells shown on the map. Deposits can be found from three Pleistocene glacial advances--the Kansan, the Illinoian, and the youngest, the Wisconsin. The terminal moraine is composed of till, an unsorted mixture of clay, rocks, and sand forming a ridge at the southernmost extent of the ice. The moraine averages five to twelve (5 - 12) feet in thickness (Gill and Vecchioli, 1965). Stratified deposits are formed as streams rework the material carried by the ice. Thickness of the Wisconsin stratified deposits vary from very shallow to about one hundred-fifty (0 - 150) feet. The deposits are clay, sand, and gravel and can be confined (water separated from atmosphere by impermeable material, Davis and Dewiest, 1966). Thickness of the older drift deposits are generally less than the Wisconsin deposits but similar in composition.

Kame and esker deposits are icecontact deposits composed of sand gravel. A cross section through the Quaternary deposits based on logs shows the variable material and thickness of the stratified drift. Four of the wells have clay layers acting as confining strata (semipermeable to impermeable layers which minimize water percolating into the underlying aquifer).

Faulting in the region is important as the presence as the fractures in the bedrock formations can increase the permeability. The Paleozoic bands are bounded by faults with others between individual formations. Another major fault area is the boundary of the Precambrian and Triassic rocks, particularly north of Boonton Reservoir.

B. Geologic Setting

The Unconsolidated Quaternary Aquifer System (Rockaway River Drainage Basin) is part of the Passaic River Basin in northern New Jersey, about thirty-five miles (35 mi.) west of New York City and twenty miles (20 mi.) west of Newark, New Jersey. The Rockaway River Drainage Basin (135.7 square miles) can be divided into two sub-basins--the Upper Rockaway Drainage Basin (116 square miles) and the Lower Rockaway River Drainage Basin (19.7 square miles), separated by the Boonton Reservoir.

The Unconsolidated Quaternary Aquifer System (Rockaway River Drainage Basin) is situated partly in the New Jersey Highlands section of the New England physiographic province and partly in the Piedmont province. The topography in the Highlands is marked by frequent flattopped ridges rising to about 1,000 feet in elevation. Many of the larger ridges trend northeastsouthwest. The ridges are separated by narrow valleys such as the upper portion of the Rockaway River from Longwood Lake almost to Washington Pond. Below Washington Pond the river cuts across this trend and flows in a southeast direction. In the Piedmont province of the near Montville and Dover, surface elevations are about three-hundred feet (300') above sea level. The gently sloping plain isbroken by low hills and several basaltic ridges which rise to about five-hundred feet (500') above sea level.

C. Ground Water Hydrology

Ground water movement is closely associated with the Rockaway River drainage basin. Most of the ground water from the Quaternary deposits flows into the Rockaway River Basin Area; however, a small portion flows south into the Lamington River. The deposits along these two rivers constitute separate ground water flow schemes. Water moves through the rock aquifer by means of secondary permeability created by fractures. These fractures occupy a relatively small portion of total rock volume. The water moves from high to low areas and into unconsolidated deposits. These deposits, which constitute the aquifer, naturally discharge to surface water, mainly the Rockaway River.

1. Recharge

The stratified drift deposits are highly permeable, and the bulk of the Unconsolidated Quaternary Aquifer System is recharged directly from precipitation on the outcrop areas of these unconsolidated deposits. Prime aquifer recharge zones are defined as highly permeable soils overlying the aquifer. Specifically, for the Rockaway River Basin Area, the recharge zone consists mainly of the floodplain areas of 1) the Rockaway River Basin, including Beaver Brook, Green Pond Brook and the Rockaway valley and 2) the Black (Upper Lamington) River Basin in Roxbury Township. This area is encompassed by all or a portion of the following municipalities: 1) Town of Boonton, 2) Boonton Township, 3) Denville, 4) Dover, 5) Jefferson Township, 6) Mine Hill, 7) Mountain Lakes, 8) Randolph, 9) Rockaway Borough, 10) Rockaway Township, 11) Roxbury, 12) Victory Gardens, and 13) Wharton. The Rockaway River and its tributaries during drought periods would recharge the aquifer through river sediments. The inflow of surface water to the deposits occurs where heavy pumping reverses ground water flow, thus the recharge from the river to the aquifer occurs.

Recharge from the crystalline rock underlying the Quaternary deposits is probably small compared to that from direct precipitation.

Some of the consolidated rock upland areas recharge the aquifer, and some discharge to the surface through streams, seeps and springs which tend to dry up during periods of drought. This indicates the limited storage potential of the upland rock aquifers. Additionly septic tank dischargesrecharge the aquifer with contaminated water; however, upon completion of the Rockaway Valley Regional Sewerage Authority Treatment Plant and sewer system, there should be a significant decrease in septic tank users and thus a reduction in this recharge component.

2. Streamflow Source Zone

The streamflow source zone is the upstream area of losing streams which flow into the recharge area. The streamflow source zone includes the designated aquifer and its recharge zone and is delineated by the Rockaway River Basin (a subbasin of the Passaic River, a portion of the Black (Upper Lamington) River Basin in Roxbury Township and Lake Arrowhead in Denville and Mountain Lakes. This zone encompasses all or part of the communities previously identified above. Under natural conditions, ground water discharges to the Rockaway River from the Unconsolidated Quaternary Aquifer. During late summer and fall, this discharge may constitute the major portion of stream flow.

D. Ground Water Use

Table 3 shows the population served by public water suppliers within the Aquifer Service Area (ASA). Table 2 shows the estimated safe yield by Geologic Formation from the ASA.

III. Ground Water Sources

A. Exchange Between River and Aquifers

The exchange between the river and underlying aquifers is especially important since surface water rights are held by Jersey City and ground water rights by Morris County. There are several methods for estimating the exchange but the only one which could be used due to data deficiencies was stream gauging. The Upper Rockaway River was gauged on September 23, 1977 under low flow conditions and November 18, 1977 under moderately high flow conditions. On each date the change in flow between the gauged station is calculated and tributary flows subtracted to obtain average ground water accretion in that river reach. In the upper reaches in the Paleozoic belt the river is a gaining stream with an average accretion of 0.76 cfs/mile. The stream continues to gain as it flows through the terminal moraine. In the stratified drift areas the exchange seems to berelated to pumping. In the reach between the first two November stations where no major supply wells are located, the river gained about 2.1 cfs/mile while in reaches with heavy pumping such as between Denville and Rockaway Borough the river losses water at an average rate of 0.76 cfs/mile. The large gain in streamflow between stations in November may reflect lower pumping rates after summer irrigation is over. These results do not cover enough time to clearly show seasonal pumpage rates. Under the low conditions of summer, the ground water table would be low exfiltration from river to ground water if the water table is below the river level. During winter high flow conditions, the expected exchange with a high water table, partly due to decreased pumpage, would be more infiltration from the ground water to surface water. If the water had been above river level the flow would change from exfiltration to infiltration. Under average flow conditions, each river reach is either a gaining or losing reach depending on the difference between the water table and river level. In general it seems that the upper part of the river above Mill Creek is gaining ground water; whereas downstream to the reservoir the river is recharging the ground water system.

B. Quaternary Formations

The Quaternary deposits in the area include ground moraine, terminal moraine, Wisconsin stratified drift, older stratified drift from the Kansan or Illinoian stages, and alluvium. The ground moraine is thin and unimportant as a source of water. It is found over much of the land surface north of the terminal moraine. The terminal moraine ranges from a few feet to about twelve feet in thickness and consists of clay, boulders, sand, and gravel. The moraine is more important as a partial confining layer for the stratified drift deposits than as a significant source of water. The Wisconsin stratified drift deposits are the most important source of water in the RVRSA service area.

The stratified drift deposits consist of clay and sand layers mixed with gravelly sand zones. The discontinuous nature of the sand layers is due to deposition by meltwater streams. The thickness of the drift deposits as determined from drillers logs ranges from fifty to one hundred seventy-five feet (50 - 175'). Both confined and unconfined deposits occur in the area. The confined and unconfined deposits were located by examining the available drillers' logs and water level data.

It is important to understand that whether the aquifer is confined or unconfined may depend on the location. The aquifer may be unconfined (open to the atmosphere) in a stream valley but confined (separated from the atmosphere by relatively impermeable material). The recharge to aquifer A, B, and C (Figure 5) would be primarily from percolation in zone R through the upper aquifers and semipermeable layers. If the material above aquifer D is impermeable with very little or no leakage from aquifer C, the recharge to aquifer D would probably be from direct precipitation on outcrop areas. The latter are not shown on this cross-section.

Recharge to the confined stratified drift deposits can occur by vertical percolation through the overlying moraine deposits similar to aquifer C or by lateral migration in response to the regional gradient similar to aquifer D. In the large confined area shown, there is a clay layer between twenty-five to ninety feet (25 - 90') thick. This layer would act as a confining layer but some leakage probably does occur since most clay is not one-hundred percent (100%) impermeable. In the lower part of the area, the deposit is covered by the terminal moraine and in the northern part by ground moraine. In this particular section, much of the recharge may be from the surrounding Quaternary deposits and to a limited extent the Precambrian formations. In another area along the river at the site of Dover Production Well Number 5, pump tests suggest that the Quaternary deposits are confined but there is no definite confining layer above the waterbearing zone, only poorlysorted fine to very fine sand, gravel, and cinders (Geraghty and Miller, 1972).

For the bulk of the Quaternary deposits, recharge is from precipitation on the outcrop areas (Gill and Vecchioli, 1965). In some areas the moraine may act as a partially confining layer. Whether clay or till layers are present at a particular site has to be determined from driller's logs of specific wells.

The drift deposits in Wharton, Dover, Rockaway Borough, and the Boonton Town Well Field have been heavily developed. Of 42 existing public supply, industrial and commercial wells, the maximum yield is l,625 gpm and the minimum 20 gpm with an average yield of 482 gpm.

ALMATONG WELL FIELD

The Almatong Well Field, located on the Black River in Randolph and Roxbury Townships, is being developed by the Morris County MunicipalUtilities Authority (MCMUA). The well field is about six-hundred (600) acres in size and has an estimated yield of five to seven (5 - 7) mgd (Decker, 1978). At present two wells supply water to Mine Hill and Randolph Townships. The well field taps Wisconsin stratified drift deposits which are at least one hundred-sixty (160) feet thick. The yields of the present wells are greater than 1,000 gpm with very high specific capacities of over 200 gpm/ft. There are two aquifers at forty to eighty feet (40 - 80') and one-hundred-ten to one-hundred-sixty feet (110 - 160'). The lower aquifer is confined and the small drawdown during pump tests suggests that the upper aquifer is unconfined.

C. Precambrian Formations

The Precambrian rock types found in the region include the Franklin Limestone, the Pochuck Gneiss, the Losee Gneiss, and the Byram Gneiss. From a water supply perspective, the rocks can be grouped together. The permeability of the rocks is low except where faulting, fracturing, and weathering have developed secondary permeability. The well yields vary from 4 to 300 gpm are higher in the fault zones. Average yield is 87.5 gpm. Permeability ranges from 10 to 411 gal/day/ft². Most of the Precambrian aquifers are unconfined, although some local areas are confined by clay layers in the Quaternary deposits which causes some wells to flow such as McWilliams Forge Company's well in Rockaway Borough. The recharge areas for the Precambrian Formations are in the outcrop areas at the highest elevations. The general flow pattern is from these areas to the river.

D. Paleozoic Formations

Paleozoic rocks are confined to a narrow belt in the north and north-western part of the Rockaway Valley service area. Rock types include black shale, sandstone, conglomerate, and limestone. Within the service area, only the sandstone units of the Green Pond Conglomerate are used for water supply purposes. The shale units have poor waterbearing properties due to the low permeability. The Kittatinny Limestone has a high permeability and high yield where solution cavities have formed. This formation underlies Quaternary deposits in the northeastern part of Roxbury Township and the southern part of Rockaway Township. The recharge to these formations is mostly derived from direct precipitation on the out-crops. In places where drift deposits overlie the bedrock, the recharge is from percolation through the drift deposits

E. Triassic Formations

Triassic formations including sandstone, shale, and basalt underlie most of the Lower Rockaway River Drainage Basin. Near outcrop areas where recharge occurs, the water in the deposits is unconfined. In low-lying areas, glacial or recent deposits of clay and silt may act as confining layers. Fracturing in the shale beds contribute most of the permeability. Differences in layer permeability and degree of fracturing can result in deeper confined zones. The highest yield wells are found where several confined zones are tapped between 200-500 feet deep (Gill and Vecchioli, 1965). The Triassic shale and basalt deposits are the source of part of the Montville Township supply which includes three wells pumping a total of O.l9 mgd in 1976.

IV. Susceptibility to Conamination

The shallow nature of the aquifer and the permeability of the overlying soils make the aquifer readily susceptible to certain types of contamination. Introduction of pollutants into the aquifer can occur directly by infiltration through the surface or, where pumpage is heavy, by induction from contaminated rivers or lakes. Localized pollution from chemical contaminants disposed of in waste lagoons, pits and landfills constitute a major threat to public and private supplies. There are industrial activities in many of the Area municipalities. Halogenated hydrocarbons and other volatile organics have been polluting the public water supply wells in Dover, Rockaway Borough, Rockaway Township and Wharton. Gasoline storage tanks, gasoline spills, oil/wastes separator operations and septic tank effluent are also known sources of pollution in the Rockaway River Basin Area. Stream sediments downstream of industrial waste seepage ponds have been found to contain high concentrations of heavy metals. The high density industrial and residential areas of Denville, Dover, Rockaway Borough, Rockaway Tcwnship, Victory Gardens and Wharton are completely sewered, but filtration of sewage from leaking pipes constitutes a threat to both surface and ground water quality. In the Rockaway Borough and Township areas, several production wells are equipped with activated granular carbon units for treatment of volatile organics before drinking water can be delivered to residents. In other areas, there are individual activated granular carbon units for each homeowner.

V. Alternative Sources of Drinking Water

The Town of Boonton has a reservoir with a capacity of 125 million gallons located within the Rockaway River Basin; however, the reservoir water is of poor quality and has been used principally to supply industrial customers. Recently, the Town has constructed a water treatment plant in order to meet potable water standards for the use of the reservoir water, which Jersey City now uses as a reserve supply for its potable system through interconnections during water shortages and other emergencies. These various arrangements create a situation where demand often exceeds the reservoir yield. With the exception of this reservoir, all other surface supplies have been fully developed for customers outside of the area. The availability of the Boonton Reservoir water for potable use is of a temporary nature and cannot be depended upon in times of severe drought when all surface supply systems will be impacted. During the 198081 Drought, temporary measures included augmenting the Rockaway River by pumping water from Lake Hopatcong at the rate of 25 mgd for 100 days. If additional need is mandated, it has been suggested that ground water located 1,200 feet below the surface in abandoned iron mines in Rockaway Township could be pumped into a tributary of the Rockaway River at a substantial cost. Based on available information, water resources within and adjacent to the Rockaway River Basin Area are fully committed and, in several instances, overtaxed. There are no alternate sources of drinking water available which are sufficient to supply the needs of the Rockaway River Basin communities.

VI. Summary

Based upon the information presented, the Unconsolidated Quaternary Aquifer System (Rockaway River Basin Area) meets the technical requirements for Sole Source Aquifer designation. More than fifty percent (50%) of the drinking water for the aquifer service area is supplied by the Aquifer System. In addition, there are no economically feasible alternative drinking water sources which could replace the Unconsolidated Quaternary Aquifer System (Rockaway River Basin Area). It is therefore recommended that the Unconsolidated Quaternary Aquifer System (Rockaway River Basin Area) be designated a Sole Source Aquifer. Designation will provide an additional review of those projects for which Federal financial assistance is requested, and will ensure ground water protection measures, incorporating state and local measures whenever possible, are built into the projects.

VII. Selected References

1. Darryl F. Caputo, Environmental Design for the Boonton Quadrangle, New Jersey, (Third Draft) 1976. New Jersey Department of Environmental Protection. pp. 76.

2. Karen Summers, Gary Bigham, Young Yoon, and Jim Pagenkopf, Determination of Availalbe Water Supply in the Rockaway Valley Regional Sewerage Authority Service Area, Morris County New Jersey, 1979. Tetra-Tech, Inc. pp. 150.

3. "Final Report Land Use Inventory and Survey and of Existing Constraints and Uses", 1977. ESCA-TECH.

4. "An Evaluation of Ground Water Resources of the Rockaway River Valley within the Communities of Denville, Boonton Township, Town of Boonton; Montville and Mountain Lakes, New Jersey", 1978. Geraghty and Miller.

5. "Special Report 25 Availability of Ground Water in Morris County, New Jersey", 1965. Gill and Vecchioli.

6. "A Report on The Succasunna Plains in Roxbury and Randolph Tcwnships", 1976. New Jersey Department of Environmental Protection.

VII. Tables

Table 1. Stratigraphic Section in Morris County, New Jersey

Sources: Gill & Vecchioli, USGS Special Report No. 25, 1965.

Table 2. Estimated Safe Yield by Geologic Formation

* Based on area of formation within the Upper Rockaway River Drainage Basin excluding surface water.

Table 3. Population of Towns

VIII. Figures

Rockaway Figures

 

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