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Ridgewood Area Aquifer System ( Brunswick
Shale and Sandstone)
Ridgewood Area Aquifer System ( Brunswick Shale and Sandstone )
Support DocumentBergen County, New Jersey |
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 July 4, 1979 the Committee to Keep Our Water Pure, which is composed of citizens who reside within the village of Ridgewood water service area (Midland Park, Glen Rock, Wyckoff and Ridgewood, New Jersey), petitioned the Administrator of the United States Environmental Protection Agency to designate the Shale and Sandstone (Brunswick) aquifer in the Ridgewood Area sole source aquifer under the provisions of the Safe Drinking Water Act.
C. Area of Consideration
The Ridgewood area sole source aquifer system determination would apply to a seventeen-point-five (17.5) square mile area which encompasses all of the communities of Ridgewood, Glen Rock, Midland Park and Wyckoff in Bergen County, New Jersey. The location of the designated area is shown in Table 1. The external perimeter of the designated area is described by the noncommon community boundaries of Ridgewood, Glen Rock, Midland Park and Wyckoff and is shown on Table 2.
The public water supply system of the Village of Ridgewood Water Department is the only water purveyor serving the 62,820 residents of the four communities. The Village of Ridgewood Water Department operates fifty-nine (59) wells which have a rated maximum dependable ground water yield potential of approximately 7.5 million gallons per day (MGD). The average daily usage is 6.4 MGD with a short term demand on peak days during the summer months rising to as high as 17.8 MGD.
D. Precipitation
Precipitation falling on the land surface in the local watersheds is the only source of recharge to the Brunswick Formation. The quantity of ground water ultimately available to the bedrock wells will vary with amounts of and long-term trends in precipitation. The yearly average from 1952 to 1977 is 50.13 inches, but has ranged from a minimum of 34.80 inches in 1964 to a maximum of 68.32 inches in 1972. A community with no alternative water sources should base their ground water supply on quantities available during minimum recharge conditions. Such a period occurred in the Ridgewood area from 1963 to 1966.
II. Hydrogeology
A. Geologic Framework
The Ridgewood Area is located in northwest Bergen County, New Jersey, which lies within the Piedmont physiographic province. In Bergen County, the Piedmont physiographic province is approximately twenty (20) miles wide and is underlain by the Triassic Brunswick Formation (about 190 million years old).
B. Geologic Setting
The Brunswick Formation consists of soft red shale interbedded with coarse grained sandstone and conglomerate. The rock beds dip gently to the northeast. In places a fine grained trap rock (Diabase) intrusion is found along the eastern portion of the province into the Brunswick Formation. Thickness of the trap rock generally is less than twenty (20) feet. This intrusion forms the Palisades. Along the western portion of the province flows of trap rock have occurred which form the Watchung Mountains, abasaltic lava flow. The Watchung basalt crops out on the land surface in a small area in the southwestern corner of Wyckoff.
The diabase sill of the Palisade of the Brunswick Formation forms the eastern boundary of the formation. A geologic crosssection is shown is Figure 3. The Brunswick Formation also extends north into New York and south into Pennsylvania. Overlying most of the bedrock are unconsolidated glacial deposits of the Pleistocene Epoch (roughly 14,000 to 80,000 years ago). Till, commonly a mixture of sediments ranging in particle size from clay to boulders, thinly mantles much of the area, particularly the upland areas. Elsewhere, the unconsolidated deposits mantling the bedrock consist of stratified outwash or alluvium deposits, which are coarser and more permeable than till. The thickness of the stratified deposits ranges from a few feet to as much as eighty feet (80') along the Ho-Ho-Kus Brook in Wyckoff.
C. Ground Water Hydrology
Ground water movement throughout the Ridgewood area is generally localized in nature, typically mirroring surface drainage patterns. Flow with the Brunswick Formation occurs in small fractures or cracks in the rock. Most of the Brunswick Formation fractures in the Ridgewood area are probably less than one-quarter (1/4) of an inch thick. The occurrence and size of fracture openings decrease with depth because of the increasing weight of the overlying rock. Wells in the Brunswick Formation are as deep as four-hundred feet (400'), but most water is usually found in the upper two-hundred feet (200') of the formation because the frequency and size of fracture openings decrease with depth.
Highly permeable soils overlying the Brunswick Formation in the vicinity of the Ridgewood Area constitute an area roughly eighteen (18) square miles. Average precipitation in the area is slightly over fifty inches (50") per year; however, precipitation available for recharge is estimated to average approximately twenty eight inches (28") per year. Therefore, the maximum recharge potential for the eight (8) square mile Ridgewood Area along is approximately twenty-four (24) MGD. Not all of this water is available to the existing well system which presently withdraws an average of 6.5 MGD (twenty-seven percent (27%) of the recharge potential). Recent studies have shown that the present average withdrawal rate of 6.5 MGD could be increased to as high as 8 MGD which is roughly thirty-four percent (34%) of the recharge potential.
1. Recharge
The primary source of ground water recharge is by infiltration of precipitation into the zone of aeration with subsequent downward percolation to the water table. Recharge to the bedrock aquifer in the Ridgewood area is dependent in large part upon the amount and concentration of precipitation that falls on the land surface. Much of the precipitation is lost by evaporation and transpiration-the use of water by plants. The evapotranspiration loss in the Ridgewood area, based on studies made in similar areas, probably ranges from twenty to twenty-four inches (20-24") per year.
2. Discharge
Ground water moves through the bedrock from the higher elevated areas to the lower areas, ultimately discharging into surface streams.
3. Streamflow Source Zone
The streamflow source zone for the Ridgewood area includes the Ho Ho Kus Brook, the Saddle River Run drainage basins. These streams pass over sand and gravel deposits which range in thickness from twenty to fifty feet (20-50'). Potentially, these conditions could be responsible for an increase in ground water yield of as much as one million gallons per day. The drainage basins for Ho Ho Kus Brook and Saddle River Run, upstream of the Ridgewood area, include all or portions of the following New Jersey municipalities: Franklin Lakes, Ho Ho Kus, Saddle River, Upper Saddle River, Woodcliff Lake, Hillside, Washington, Montvale, as well Ramapo Township, New York.
D. Ground Water Quality
Data provided from recent water samples taken from the Ridgewood system indicate that the supply quality is significantly superior in regards to the minimum Federal requirements for constituents sampled. Unfortantely, three well systems, within a ten mile radius of the Ridgewood area, have been forced to close. Three wells in Fair Lawn, New Jersey were found by the NJDEP to contain high levels of: carbon tetrachloride, trichloroethylene, tetrachloroethylene, methylene chloride and chloroform. At least four wells in Mahwah, New Jersey were found by NJDEP to be contaminated with trichloroethylene and tetrachloroethylene. Three wells in Allendale were found by NJDEP to be contaminated with tetrachloroethylene. The Fairlawn and Allendale wells remain closed.
E. Designated Areas
The area that has been designated as the Sole Source Aquifer is defined as the external perimeter described by the non-common community boundaries of Ridgewood, Glen Rock, Midland Park, and Wyckoff. The area is bounded on the west by the First Watchung Mountain which precludes regional movement of ground water from the area.
F. Ground Water Use
The pubic water supply system of the Village of Ridgewood Water Department, the private water supply of a bottled spring water purveyor (Belmar Spring Water, Glen Rock, New Jersey) and many industrial and private well owners depend on the aquifer system as a sole source of drinking water. A 1979 study by Metcalf and Eddy Engineers of New York, New York, estimated the resident population to be 62,820 in the area proposed for designation. The population is distributed throughout the area's four communities as follows:
| Community | Population |
|---|---|
| Ridgewood | 26,434 |
| Glen Rock | 12,367 |
| Midland Park | 7,863 |
| Wyckoff | 16,156 |
The residents are dependent upon the Village of Ridgewood Water Department as a purveyor of the Deep Shale and Sandstone Aquifer water except for about 1,200 people in Wyckoff who have private wells in the aquifer.
III. Susceptibility to Contamination
The Ridgewood Aquifer System is highly vulnerable to contamination, due to highly soil permeability and shallow depth to ground water. The present water quality of ground water in the Ridgewood area is significantly better than standards established by the Safe Drinking Water Act. Concentrations of metals, pesticides, chlorinated hydrocarbons, nitrates and herbicides are small. The water quality characteristics of Ridgewood water make it a highly desirable potable water source.
The densely developed and industrialized environment of northern New Jersey contains many potential sources of ground water contamination. These include storm water runoff, landfills, chemical spills from industry, and waste disposal lagoons. Ground water is also contaminated by septic systems and highway deicers. Current Federally sponsored projects, which could have a beneficial potential impact on the Ridgewood area, include wastewater collection, treatment, and disposal facilities.
IV. Alternative Sources of Drinking Water
The portion of the Brunswick shale and sandstone aquifer which underlies the Ridgewood Area is a sole source of drinking water for public and private well supplies in the area. Furthermore, contamination of this aquifer would create a significant hazard to public health.
According to the New Jersey Statewide Water Master Plan, there are existing interconnections between the Ridgewood Water Department and Hackensack Water Company water systems. However, these inter-connections are designed for emergency use and are inadequate for transfer of water from other sources to the Ridgewood system to meet demand.
There are currently no interconnections between the Ridgewood Water Department and the Passaic Valley Commission. In the future, water supply for the Ridgewood Area could be made available from adjacent supplies in the area - the Hackensack Water Company on the east and the Passaic Valley Water Commission (PVWC) on the west. Supplies are currently available from PVWC but the interconnections do not exist to transport the water. The completion of the Wanaque Sough Project (1986 target) would, in the future, also allow the Hackensack Water Company to meet the supply demands of the Ridgewood Area. Both sources of supply would be predicated on the expansion of the existing interconnections and modification to the transmission and distribution system. Alternative sources of water supply which are capable of supplying the Ridgewood Area with its daily water needs do exist; however, an interconnection system for handling this demand does not.
V. Summary
Based upon the information presented, the Brunswick Shale and Sandstone Aquifer System of the Ridgewood 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 Brunswick Shale and Sandstone Aquifer System. In addition, there are no economically feasible alternative drinking water sources which could replace the Brunswick Shale and Sandstone Aquifer System of the Ridgewood Area. It is therefore recommended that the Brunswick Shale and Sandstone Aquifer System of the Ridgewood 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.
VI. Selected References
1. "The New Jersey Statewide Water Supply Master Plan, Task IV -Interconnections", 1980. New Jersey Department of Environmental Protection (NJDEP).
2. "Northeast New Jersey Water Quality Management Plan", 1979. NJDEP.
3. "Geology of Bergen County in Brief", 1971. Carol S. Lucy, New Jersey Geological Society.
4. "Evaluation of Dependable Ground Water Yield Potential of the Bedrock Aquifer, Ridgewood, New Jersey", 1978. Leggette, Brashears, and Graham.
5. "Village of Ridgewood, Bergen County, New Jer Jersey - Water System Master Plan," 1976. Alfred Crew Consulting Engineers, Inc.
6. "Report to the Village of the Ridgewood on Projected Water Supply Needs of the Ridgewood Water Supply System," 1979. Metcalf and Eddy.
VII. Tables
Table 1. Water Supply Alternatives
| Source |
Cost per1000 gals
|
Ratio of Cost to R.W.D.
|
|---|---|---|
| Ridgewood Water Dept - user's tap |
$0.66
|
1
|
| Adjacent community water system |
( 2 )
|
( 2 )
|
| Lehigh Valley Spring Water - supermarket |
$330.00
|
500
|
| Perrier Carbonated Water - supermarket |
$2,086.96
|
3,162
|
| Saratoga Water -supermarket |
$1,577.14
|
2,390
|
| Montclair Water -supermarket |
$1,993.69
|
3,021
|
| Poland Water -supermarket |
$3,032.38
|
4,595
|
| Deer Park Uncarbonated -supermarket |
$590.00
|
894
|
| Deer Park Carbonated -supermarket |
$1,348.57
|
2,043
|
| Grand Union Bottled Water - supermarket |
$390.00
|
591
|
1) R.W.D.= Ridgewood Water Department
(2) Agreements cover emergency supply only and do not provide for
continuous supply which R.W.D. would need should area wells become
contaminated.
Table 2. Drainage Basins of the Brunswick Shale and Sandstone Aquifer System of the Ridgewood Area
| Basin Name | Area (Square Miles) |
Number of Wells |
Yield (gallons per day) |
|---|---|---|---|
| Deep Brook Basin | 1.43 | 10 | 610,000 |
| Diamond Brook Basin | 3.13 | 5 | 1,330,000 |
| Goffle Brook Basin | 4.79 | 17 | 2,040,000 |
| HoHoKus Midland Park Ridgewood Basin | 0.89 | 4 | 380,000 |
| HoHoKus Brook Wyckoff Basin | 1.94 | 0 | 200,000 |
| Passaic River/Saddle River Basin | 0.73 | 1 | 310,000 |
| Saddle River-HoHoKus Brook Basin | 4.61 | 22 | 3,000,000 |
| Squaw Brook Basin | 0.32 | 0 | 0 |
Source: Petition from Committee to Keep Our Water Pure, 1979.
Table 3. Population for the Brunswick Shale and Sandstone Aquifer System of the Ridgewood Area
| Community | Population |
|---|---|
| Ridgewood | 26,434 |
| Glen Rock | 12,367 |
| Midland Park | 7,863 |
| Wyckoff | 16,156 * |
| Total | 62,820 |
Source: A 1979 study by Metcalf and Eddy Engineers of
New York, NY.
* About 1,200 people in Wyckoff who have private wells in the aquifer.
VIII. Figures