[Ord. No. 01-01 § 1001]
The Borough of Tenafly, pursuant to the provisions of N.J.S.A. 40:48-2, has been given the authority by the State Legislature to make, amend, repeal and enforce such ordinances, regulations, rules and by-laws not contrary to the laws of the State of New Jersey or of the United States of America, as it may deem necessary and proper for the protection of persons and property and for the preservation of the public health, safety and welfare of the municipality and its inhabitants. Such authority is in addition to the authority otherwise given to the municipality to regulate land and control flooding and water pollution pursuant to N.J.S.A. 40A:27-1 et seq.; 4:24-1 et seq.; 40:14-1 et seq.; 58:25-23 et seq. and 40:55D-1 et seq.
[Ord. No. 01-01 § 1002]
a. 
The uncontrolled flow of storm water and surface drainage within the Borough of Tenafly poses a danger to the public health, safety and welfare of the Borough of Tenafly and its inhabitants through flooding, soil erosion, and damage both to private and public property.
b. 
In order to protect persons and property and preserve the public health, safety and welfare, the Mayor and Borough Council finds that it is in the best interests of the citizens of the Borough of Tenafly to regulate storm water and surface drainage.
[Ord. No. 01-01 § 1003]
a. 
Except as otherwise specifically preempted by other applicable County, State or Federal statutes, ordinances, rules and regulations, the provisions of this Article shall apply to all regulated activities, as hereinafter defined, within the Borough of Tenafly.
b. 
The purpose of this Article is to supplement the applicable provisions of other statutory provisions including provisions respecting flood hazard areas, stream encroachment permits, New Jersey Residential Site Plan regulations and any other statutes or regulations respecting flooding, pollution control, soil erosion, or land use development. To the extent that the provisions of this Article are inconsistent with such other statutory or regulatory provisions and/or are preempted by such statutory and regulatory provisions, the provisions of this Article shall not apply.
c. 
This Article shall only apply to storm water management facilities constructed as part of any of the regulated activities as hereinafter defined. Storm water management and erosion and sedimentation control during construction involved with any of these required activities are specifically not regulated by this Article, but shall be regulated under existing laws and ordinances, including those of the New Jersey Soil Conservation Service, as administered by the Borough Engineer of the Borough of Tenafly.
[Ord. No. 01-01 § 1004]
IMPERVIOUS SURFACE COVERAGE
Shall include paved areas or other areas upon which is constructed any building or structure which does not permit the free passage of storm water or surface drainage into the ground including, but not limited to, any roof, parking or driveway areas and any new streets and sidewalks constructed as part of or for the proposed regulated activity. For the purposes of this definition, any areas that may be designated to be semipervious initially (e.g. gravel, crushed stone, etc.) shall be considered impervious areas.
REGULATED ACTIVITIES
Include:
a. 
Construction of new or additional impervious surfaces (e.g. driveways, parking lots, sidewalks, patios, swimming pools, etc.) exclusive of replacement of existing impervious surfaces.
b. 
Construction of new buildings or additions to existing buildings.
c. 
Diversion or piping of any natural or man-made stream or channel (not otherwise regulated by the New Jersey Department of Environmental Protection).
d. 
Installation of storm water systems or appurtenances thereto.
[Ord. No. 01-01 § 1005]
Any proposed regulated activity, except for the diversion or piping of any natural or man-made stream or channel or the installation of storm water systems or appurtenances thereto, that would create 200 square feet or less of additional impervious surface coverage is exempt from the provisions of this Article. For development taking place in stages, the entire development plan shall be used in determining conformance with these criteria. In addition, if, in the opinion of the Borough Engineer, the proposed regulated activity does not result in any adverse impact upon other public or private property, the Mayor and Council of the Borough of Tenafly may waive the strict application of this Article, in whole or in part.
[Ord. No. 01-01 § 1006]
a. 
There shall be no increase in runoff experienced by any adjacent properties or streets as a result of proposed development based on the 100-year storm event. The runoff from the proposed project must be controlled such that the post-project construction peak runoff rates for the two-year storm shall be 50% of the pre-project construction peak runoff rate. The post-project construction peak runoff rates for the ten-, twenty-five- and 100-year storm shall be 75%, 75%, and 80%, respectively, of the pre-project construction peak runoff rate.
b. 
Storm drainage systems shall be provided in order to permit unimpeded flow of natural watercourses except as modified by storm water detention facilities or open channels consistent with this Article. All of the storm water runoff from roof structures of new buildings and building additions shall be controlled by seepage pits or other methods approved by the Borough Engineer. Soil tests are required to show that the site conditions (depth to ledge rock and depth to the water table) can support the use of seepage pits or the drainage system to be utilized.
c. 
The existing points of concentrated drainage discharge onto adjacent property shall not be altered without written approval of the Borough Engineer.
d. 
Areas of existing diffused drainage discharge onto adjacent property shall be mandated such that, at a minimum, the peak diffused flow does not increase in the general direction of discharge, except as otherwise provided in this Article. If diffused flow is proposed to be concentrated and discharged onto adjacent property, the developer must document that there are adequate downstream conveyance facilities to safely transport the concentrated discharge or otherwise prove that no harm will result from the concentrated discharge. Areas of existing diffused drainage discharge shall be subject to any applicable release rate criteria in the general direction of existing discharge whether they are proposed to be concentrated or maintained as diffused drainage areas.
e. 
When, due to topographic conditions, natural drainage swales on the site cannot adequately provide for drainage, open channels may be constructed conforming substantially to the line and grade of such natural drainage swales. Capacities of such open channels shall be calculated using the Manning equation.
f. 
Storm drainage facilities and appurtenances shall be so designed and provided as to minimize erosion in watercourse channels and at all points of discharge.
g. 
Water quality must be addressed with the drainage system design. Runoff from roof structures and impervious surfaces not used by vehicles can be collected and controlled by seepage pits. The storm water from streets, driveways and parking areas must be pre-treated before discharging into streams, watercourses or seepage pits. The pre-treatment must be made with the use of above ground detention basins or premanufactured sedimentation chambers. The design of the water quality measures must be designed in accordance with NJDEP standards and approved by the Borough Engineer. The water quality facilities must be located for easy future maintenance.
[Ord. No. 01-01 § 1007]
a. 
Storm water runoff from all development sites shall be calculated using either the rational method, modified rational method or SCS TR-55 methodology.
b. 
The design of any detention basin intended to meet the requirements of this Article shall be verified by routing the two, ten-, twenty-five- and 100-year design storm hydrograph through the proposed basins. All basins shall be designed using the SCS Technical Release Number 55 (TR-55) or the Modified Rational Method. If the Modified Rational Method is to be utilized a storm having duration of a minimum of 60 minutes shall be utilized to approximate the volume required for the detention basin. For basins designed using the Modified Rational Method technique, the detention volume shall, at minimum, equal the volume derived from the approximate process as contained in SCS Technical Release Number 55 (TR-55).
c. 
All calculations using the Rational Method shall use rainfall intensities consistent with appropriate time of concentration and return periods and the Intensity-Duration-Frequency Curves. The minimum time of concentration for design shall be 10 minutes.
d. 
Runoff coefficients for use in the Rational Method shall be based upon the 100-year storm
e. 
The Manning equation shall be used to calculate the capacity of watercourses. Manning 'n' values used in the calculations shall be consistent with standard practice. Pipe capacities shall be determined by methods acceptable to the Borough Engineer.
f. 
The location of the watershed shall be determined using topographic maps. If the storm water analysis only involves the subject property the owner shall prepare a topographic map with a scale no greater than one inch equals 20 feet. Should there be any question as to the location of the property with respect to the watershed, the Borough Engineer shall make the final determination.
[Ord. No. 01-01 § 1008; Ord. No. 11-02 § 1; Ord. No. 11-04]
Two copies of the proposed grading and drainage plan shall be submitted together with the application fee by the owner and/or developer of the subject property to the Borough of Tenafly Department of Buildings, Construction Division as part of the plan submission for a building permit or land development application, which shall be distributed one copy to the Borough Engineer and one copy to the Construction Official. Zoning approval, if required, must be obtained prior to submittal of a grading and drainage plan application.
[Ord. No. 01-01 § 1009]
a. 
The Borough Engineer and/or his designee shall inspect all phases of the installation of the permanent storm water control facilities and at the completion of the installation.
b. 
It is the responsibility of the property owner and/or developer to contact the Borough Engineer for the appropriate inspections.
c. 
If at any stage of the work, the Borough Engineer determines that the permanent storm water control facilities are not being installed in accordance with the approved development plan, the issuing authority may revoke any existing permits until a revised drainage plan is submitted and approved.
[Ord. No. 01-01 § 1010; Ord. No. 11-02 § 2; Ord. No. 11-04]
a. 
The established fees for drainage plan reviews, inspections and processing of applications shall be based on the number of hours typically spent by the Borough Engineer and/or his designee on the application and the fees established for engineering services in accordance with the most recent Fee Ordinance of the Borough of Tenafly.
b. 
The fees required for this Article shall cover:
1. 
The review of the grading and drainage plan by the Borough Engineer;
2. 
The site inspection;
3. 
The inspection of required controls and improvements during construction;
4. 
The final inspection upon completion of the controls and improvements required in the plan; and
5. 
Any additional work required to enforce any permit provisions regulated by this Article, correct violations, and assure the completion of stipulated remedial actions.
c. 
For the following categories of work, application fees are established and set forth below:
New dwellings:
$750
Additions, including garages:
$500
Grading, drainage or new impervious surface coverage:
$250
Swimming pools or tennis courts:
$250
Plan design revisions by applicant, each:
$125
The established fee set forth above shall be collected by the Department of Buildings, Construction Division, at the time an application is submitted and shall be paid to the Borough Engineer upon his certification to the Construction Official that the grading and drainage review has been completed.
[Ord. No. 01-01 § 1011]
a. 
In all cases where the permanent storm water runoff control facilities are designed to manage runoff from a property, the maintenance responsibility for the storm water control facilities shall be with the owner.
b. 
The owner must maintain the storm water runoff facilities in accordance with the initial design as submitted and approved by the Borough Engineer.
c. 
Upon presentation of the proper credentials, duly authorized representatives of the Borough of Tenafly may enter at reasonable times upon the property within the Borough of Tenafly to investigate or ascertain whether proper maintenance is being provided for any storm water management facilities designed and installed under this Article.