North Caldwell City Zoning Code
§ 107-30.2
Excessive Slope Areas. 1
[Ord. No. 2-00]
A.
Excessive Slope Areas.
(1)
Statement of purpose and definition. The governing body of the Borough of North Caldwell finds that the removal of vegetative cover, disturbance of soil and construction of buildings and structures in areas of excessive slopes will increase surface water runoff and soil erosion, thereby creating a potential for flooding, endangering public and private property and life, and that the most appropriate means of alleviating such condition and protecting natural features of geology, hydrology, vegetation, ecological balance and environmental quality is through regulation of construction and development on excessive slopes. For purposes of this subsection, the term "excessive slope" shall be defined as any slope which has a grade of 10% or more based upon New Jersey Geodetic Control Survey datum. Slopes shall be measured between two foot contour intervals.
Ord. No. 18-2008]
(2)
Excessive slope area requirements. Within any excessive slope area as defined herein, no soil or vegetation shall be disturbed nor shall any building or structure be erected, constructed or substantially enlarged unless and until it can be demonstrated by information, plans and studies furnished by an applicant that the following requirements can be met:
(a)
No soil shall be excavated, removed, deposited or disturbed within an excessive slope area except as a result of and in accordance with a site plan or preliminary subdivision plan approved under the terms of this chapter.
(b)
Proposed disturbance of soil shall be for purposes consistent with the intent of this subsection, and it shall be executed in a manner that will not cause excessive erosion or other unstable conditions.
(c)
Provision shall be made for the proper disposition of surface water runoff so that it will not create unstable conditions; appropriate storm drainage facilities shall be constructed as deemed necessary; and adequate protective measures shall be provided for downstream properties.
(d)
Provision shall be made for any structures or protective measures that proposed slopes may require for the protection of the public safety, including but not limited to retaining walls, headwalls and fences.
(e)
Proper facilities have been or will be provided for a safe water supply and for the disposal of sanitary sewage.
(f)
Any proposed building or structure or attendant protective measures will not impede the flow of surface waters through any watercourse or cause an increase in flood heights or velocities.
(g)
Any proposed building or structure shall be of sound engineering design with footings designed to extend to stable soil and/or rock with proper lateral support and when built may be occupied without peril to the health or safety of the occupants.
(h)
Any proposed vehicular facilities, including roads, drives or parking areas, shall be so designed that any land disturbances shall not cause excessive erosion. Both the vertical and horizontal alignment of vehicular facilities shall be so designed that hazardous circulation conditions will not be created.
(3)
Additional information required. Where development is proposed on slopes greater than 10% as part of a subdivision or site plan application, in addition to the other information required pursuant to this chapter, the following exhibits prepared, signed and sealed by a New Jersey licensed engineer shall be submitted:
(a)
Erodibility potential of exposed soils.
(b)
Length, steepness and surface roughness of exposed slopes.
(c)
Resistance of soil to compaction and stability of soil aggregates.
(d)
High-water table, water infiltration capacity and capacity of soil profile.
(e)
Type and location of construction activity, including the amount of site grading.
(f)
Location of construction access roads.
(g)
Any other engineering data which shall be deemed reasonably necessary by the Borough Engineer to determine compliance with this subsection.
(4)
Density modification.
(a)
In order to meet the purposes, goals and standards set forth in this subsection, the applicable provisions of this chapter relating to minimum lot sizes and density of development shall be modified in areas of slopes greater than 10%. The maximum number of dwelling units allowed on any tract shall be computed by application of the following formula:
Land with 30% or more slopes × 0.2
Land with 20% to 29% slopes × 0.4
Land with 11% to 19% slopes × 0.6
Land with 0% to 10% slopes × 1.0
(b)
Sample calculations example.
[1]
Assume a three-acre tract with 1 acre having slopes of 25% and two acres having slopes of 15%. The density modification calculation would be as follows:
1 acre — 25% slopes × 0.4 = 0.4 net acres
2 acres — 15% slopes × 0.6 = 1.2 net acres
1.6 acres
[2]
The total acreage of land available for development resulting from the above calculation which would be utilized to calculate permissible density is 1.6 acres. In zones which have a minimum lot area, said minimum shall be determined after application of the density modification formula as set forth in this subsection.
3 acres x minimum lot size as established by zoning
1.6 acres
[3]
The sample calculation set forth above illustrates the determination of the acreage of land available for development based upon the density modification created by the existence of steep slopes only and is not intended to supersede the influence of other zoning regulations that bear upon the determination of permissible density.