The provisions of this chapter shall be applicable
to development activities in the Carbonate Area District requiring
preliminary major subdivision approval or preliminary site plan approval
from the Pohatcong Township Planning Board.
[Amended 4-15-2003 by Ord. No. 03-3]
For properties located in the Carbonate Rock
District (CRD) a comprehensive geologic investigation program shall
be conducted by the applicant. The purpose of this program is to provide
the Planning Board with sufficient data to define the nature of all
existing geologic conditions that may affect construction and land
use activities on the site. Specifically, the investigations shall
yield information which shall demonstrate that the proposed development
will identify any existing geologic conditions for which appropriate
site design and/or engineering solutions may be necessary to minimize
any adverse environmental impacts caused by the project. The geotechnical
investigation program for CRD properties shall be conducted in accordance
with the five phases defined herein. For properties which can document
that they are located in the Carbonate Drainage Area (CDA), only the
Phase I portion of the geotechnical investigation program is required.
A. Phase I: Compilation and evaluation of existing data. The applicant shall prepare a Phase I submission in accordance with the requirements in §
115-6. The Phase I submission is a compilation and evaluation of existing data from various sources for the purpose of making general determinations of the types and depth of rock on the site, the extent of fracturing and faulting and an assessment of the potential development hazard which the conditions may pose. The Phase I submission will be evaluated by the GTC for the purposes of ensuring that the applicant has sufficient and current information available for preparation of a plan for detailed investigation of the proposed development site. Upon receipt of the Phase I submission, the GTC will review the submission and within 30 days from its receipt recommend to the Planning Board whether the submission is satisfactory and whether he recommends all or any portions of the Phase II requirements be waived. The Planning Board shall act on the recommendations of the GTC and notify the applicant within 30 days from the receipt of his report.
B. Phase II: Proposed investigation methodology. The applicant shall prepare a Phase II submission in accordance with the requirements in §
115-7. The Phase II submission is a detailed outline of how the proposed on-site investigation will be conducted and shall include references to site specific investigation techniques, number of tests, equipment to be used, and investigation objectives. Upon receipt of the Phase II submission, the GTC will review the submission and within 30 days from its receipt recommend to the Planning Board whether the submission is satisfactory. The Planning Board shall act on the recommendations of the GTC and notify the applicant within 30 days from the receipt of his report.
C. Phase III: On-site geotechnical investigation. The applicant shall perform an on-site geotechnical investigation in accordance with the approved Phase II submission and in accordance with the requirements in §
115-8 with observation by the municipal GTC. No on-site testing shall be conducted by the applicant until the Phase II submission has been approved by the Planning Board.
D. Phase IV: Geotechnical investigation report. The applicant shall submit a geotechnical investigation report in accordance with the requirements in §
115-9. The report shall summarize the on-site testing and geotechnical findings, shall include recommendations to minimize the potential for environmental and structural impacts resulting from development and shall address remediation techniques for the handling of sinkholes or solution cavities discovered during construction.
E. Phase V: Planning Board review and approval. The Municipal
GTC shall review the geotechnical investigation report and make final
recommendations to the Planning Board within 30 days from the receipt
of the geotechnical investigation report. The Planning Board shall
act on the recommendations of the GTC and notify the applicant of
whether the report is satisfactory within 30 days from the receipt
of his report.
Phase I requirements shall be as follows:
A. United States Geologic Survey seven-and-one-half-minute
topographic quadrangle maps with parcel identified.
B. United States Department of Agriculture Soil Conservation
Service soil survey map indicating soils present on parcel.
C. Information from any special reports completed by
the New Jersey State Geological Survey, United States Geologic Survey,
or the New Jersey Department of Environmental Protection.
D. Site plan map at a scale of one inch equals 1,000
feet identifying proposed development site and boundaries of site
that are within the CRA and/or CDA as designated on the municipal
CAD map.
E. Aerial photograph print of the proposed site and surrounding
area at a minimum scale of one inch equals 1,000 feet obtained during
period of minimum foliage.
F. Location of all known water production wells and well
log information within 1/2 mile of the project.
G. A project sketch plat at a minimum scale of one inch
equals 200 feet with existing surface water bodies, location of any
existing water production wells, faults, outcrops, springs, sinkholes,
disappearing streams, and surface water flows.
H. Written narrative describing the proposed activity.
I. If the project includes the storage or manufacturing
of toxic or hazardous materials, provide an explanation of the activity.
J. Other published geologic information which the applicant
deems pertinent, such as information from other geologic investigation
programs which are on file with the municipal clerk or other agencies.
K. Properties that are located within the Carbonate Drainage
Area (CDA) shall be required to document that the proposed development
of the property will not increase the volume or rate of stormwater
runoff or concentrate flows into solution prone areas thereby increasing
the risk of sinkhole collapse on adjoining properties. The applicant
shall also address measures, both structural and nonstructural, which
will be employed to prevent the discharge of contaminated surface
waters into limestone aquifers.
[Added 4-15-2003 by Ord. No. 03-3]
[Amended 4-15-2003 by Ord. No. 03-3]
A. At the completion of the field investigation a formal
site investigation report shall be submitted and include any of the
following required information gathered during the testing:
(1) Logs of all borings, test pits, and probes, including
evidence of cavities, loss of drilling fluid circulation during drilling,
voids encountered and similar cavities.
(2) Type of drilling or excavation technique employed.
(3) Time and dates of explorations and tests.
(4) Names of the individuals conducting the tests if other
than the New Jersey licensed engineer, New Jersey licensed well driller,
or geologic consultant provided in the Phase II requirements.
(5) Analytical methods used on soils, water samples, and
rock samples.
(6) A topographic map of the site at a scale of one inch
equals 100 feet (at a contour interval of two feet) locating all test
pits, borings, wells, seismic or electromagnetic conductivity or other
geophysical surveys in relation to the proposed development.
(7) Depth to groundwater encountered in borings.
(8) A geologic interpretation of the observed subsurface
conditions, including soil and rock type, jointing (size and spacing),
faulting, voids, fracturing, grain size, and the likelihood of sinkhole
formation, especially in projects where water from storm sewers, roof
drains, septic systems, etc. is being discharged into the ground.
B. The report shall also define the extent of geotechnical
findings at the site in relation to the planned development or land
use. The engineering solutions proposed to minimize environmental
and structural impacts for the useful life of the project as well
as during construction must be clearly detailed together with the
bases for the conclusions reached. The report shall, as a minimum,
address the following:
(1) Methods taken to avoid the probable effects of the
proposed development, including increased loadings on the soils, changes
in drainage patterns, new in-ground discharges from septic systems,
detention basins, swales, etc. on future sinkhole formation along
with recommendations for remediation to minimize the potential for
structural failures.
(2) Methods taken to avoid the probable effects of the
proposed development on the potential for groundwater contamination
considering the depth of the rock and extent of voids and fracturing,
along with recommendations for remediation to minimize the potential
for contamination.
(3) Based upon the nature of the proposed development
and considering the types of materials to be stored on the site, types
of chemicals, pesticides, fertilizers etc. to be used on-site, the
report should address the anticipated acidity of future surface water
runoff and its probable effects on the potential for increased solutioning
of the underlying rock.
(4) The appropriateness of the site for the proposed development
and the appropriateness of the location and design of proposed roadways,
buildings, and facilities for stormwater management, water supply
and sewage disposal.
(5) The adequacy of support for buildings, roadways, utility
lines.
(6) General methodology for remediation of sinkholes or
solution cavities, depressions, or other questionable areas which
have been discovered during the investigation or which could be discovered
during construction.
(7) Provisions for inspection and monitoring during construction
and any long-term inspection or monitoring which may be recommended.
It is strongly recommended that the developer employ the services
of an expert in construction in karst terrain to be on site during
all construction activities requiring excavation.
(8) Based upon the geotechnical investigation, the report
shall recommend construction methods and specifications to be utilized
in the construction of the project to minimize the potential for structural
failure and groundwater contamination. As a minimum, the following
standards shall be adhered to during the construction of the project
and shall be incorporated into the preliminary subdivision plans or
preliminary site plans for the project:
(a)
Building foundations should be reinforced to
span a minimum of 10 feet of soft soils or voids.
(b)
Detention basins, swales and ditches shall be
lined or constructed utilizing impervious materials to minimize infiltration.
(c)
Roof drains shall be connected to storm drainage
systems to minimize infiltration.
(d)
Stormwater pipes, sanitary sewer lines and water
lines shall be designed and constructed with watertight joints which
have been tested to ensure their integrity.
(e)
Pipe materials, joints, construction methods
and materials and infiltration or exfiltration testing shall be subject
to the approval of the municipal engineer.
(f)
Backfill and bedding in utility trenches shall
minimize water infiltration to the subsurface.
(g)
Pressurized utility lines shall provide for
automatic shutoff when sudden pressure loss is detected.
(h)
Site grading, blasting and excessive depths
of cuts for utility lines shall be minimized.
The GTC's review of the geotechnical investigation
report for proposed development in the CRD shall consider the data,
formal reports, maps, drawings and related submission materials and
shall advise the Planning Board whether or not the applicant has provided
the municipality with:
A. Sufficient design, construction and operational information
to ensure that the proposed development of the tract will not adversely
impact on the health, safety and welfare of the community.
B. Proof that the proposed method of development of the
tract will minimize any adverse effects on groundwater quality, and
will not alter the character of surface water flow in a manner detrimental
to known on-site or off-site conditions.
[Amended 4-15-2003 by Ord. No. 03-3]
C. Specific details insuring that design concepts and
construction and operational procedures intended to protect against
structural failures and contamination of groundwater will be properly
implemented.
[Amended 4-15-2003 by Ord. No. 03-3]
D. Specific details on inspection procedures to be followed
during construction and after project completion.
E. The following note shall be provided on the final
subdivision plat or final site plan for any project located within
the CRD: "This site is underlain by limestone formations which are
susceptible to sinkholes and subsidence. The occurrence of sinkholes
and/or subsidence is not predictable and therefore the municipality,
its employees, the Municipal Engineer, and the municipal geotechnnical
consultant assume no liability for any damages which may occur on
private property as a result of the formation of sinkholes or subsidence."
In certain situations, a specific geologic hazard
may not be identified while the geologic investigation program is
underway and may be discovered during or after construction. In such
cases the applicant shall:
A. Report the occurrence of the hazard to the Municipal
Clerk within 24 hours of discovery.
B. Halt construction activities which would impact the
geologic hazard.
C. Prepare a report on the geologic hazard which analyzes
the impact of the hazard and details a remediation plan for review
and approval by the municipal geotechnical consultant.
D. After obtaining approval from the municipality, perform
necessary remediation of the hazard to prevent or minimize damage
to buildings, structures, utilities, driveways, parking areas, roadways,
and other site improvements, and to minimize pollution of the groundwater.
E. Repair any damage to improvements and restore ground
cover and landscaping.
F. In those cases where the hazard cannot be repaired
without adversely affecting the site plan or subdivision, the applicant
shall file an amended application for site plan or subdivision approval
in compliance with the provisions of this chapter.
Subsequent to the submission of the Phase I information required in §
115-6, the Planning Board, upon recommendation by the municipal geotechnical consultant, may grant a waiver from all or any part of the geotechnical investigation and report requirements in §§
115-7,
115-8 and
115-9.