The following measures represent the minimum requirements necessary to satisfy the no net increase provisions of this chapter. A project's stormwater management plan shall be designed in accordance with the Department of Community Affairs' Residential Site Improvement Standards (N.J.A.C. 5:21) as promulgated, the requirements of the Municipal Land Use Law (N.J.S.A. 40:55D-95), the provisions of the Soil Erosion and Sediment Control Act (N.J.S.A. 4:24-39) and any NJDEP approved stormwater management regulations. For guidance regarding conformance with the provisions of this chapter, applicants are directed to the "Stormwater and Nonpoint Source Pollution Control Best Management Practices Manual" (BMP Manual) dated December 1994 and authored by NJDEP and New Jersey Department of Agriculture, or the most recent revision thereto. Applicants will be required to demonstrate that the project plan has considered current techniques suitable for attaining the objectives of this chapter.
A. 
No net increase in stormwater quantity.
(1) 
Stormwater control systems.
(a) 
Stormwater control systems shall be designed to control stormwater runoff resulting from a development site such that the postdevelopment peak runoff rates from the site shall be 50% of the predevelopment peak for the two-year storm event, 75% of the predevelopment peak for the ten-year storm event and 80% of the predevelopment peak for the one-hundred-year storm event.
(b) 
If a stormwater management plan for the region or watershed containing the watercourse affected by the proposed development has been adopted, the project's stormwater control systems shall be designed to conform to that regional or watershed plan, to the extent practicable in satisfying the requirements of Subsection A(1)(a) above.
(c) 
Stormwater control systems shall be designed, to the extent practicable, to infiltrate the quantity of runoff that exceeds predevelopment runoff for the NJDEP Water Quality Design Storm (1.25 inch two-hour rainfall). If infiltration on site for the design storm is not practicable (i.e., for example based on soil permeability constraints, topography or groundwater level considerations), an applicant shall provide off-site mitigation subject to the approval of the Planning Board prior to project commencement. Options for mitigation are as follows:
[1] 
The acquisition of and mitigation on privately owned lands, preferably adjacent to state open water and nearby and within the same drainage basin, located in the sewer service area/applicable watershed to be dedicated for preservation or reforestation, in equivalent size and used to off set the increase in volume of the 1.25 inch two-hour rainfall from the proposed development site.
[2] 
Mitigation on previously developed properties, public or private, and preferably nearby within the same drainage basin, that currently lack stormwater management facilities designed and constructed in accordance with the purposes and standards of this chapter. A construction cost estimate of a suitable infiltration system sized for the proposed development based on the assumption that average permeability had existed on the subject property shall be prepared and submitted by the applicant's professional engineer. Upon certification by the Township Engineer that the proposed design and estimate are reasonable, the amount so determined will be the amount required to fund the mitigation measures on previously developed properties in order to offset increase in volume of the 1.25 inch two-hour rainfall from the proposed development site.
[3] 
Funding specific projects recommended in watershed based stormwater management plans in order to offset the increase in volume of the 1.25 inch two-hour rainfall from the proposed development of the site.
[4] 
Funding stormwater related studies or regional stormwater management plans approved by the Township Council in an amount equivalent to a construction cost estimate of a suitable infiltration system sized for the proposed development submitted and prepared by the applicant's professional engineer and approved by the Township Engineer or Planning Board Engineer and local approving authority.
(2) 
This requirement shall be applied equally to all applications for development and redevelopment within the sewer service area portion of Greenwich Township. Increased stormwater runoff shall be calculated by the applicant's engineer and approved by the Township Engineer or Planning Board Engineer and local approving authority utilizing accepted engineering practices.
B. 
No net increase in stormwater pollutant loads.
(1) 
Stormwater control system shall be designed to the extent practicable so that there is no calculated or anticipated increase from predevelopment to post development conditions in conventional pollutant loads (e.g., total suspended solids, nitrogen, phosphates, etc.) to the receiving watercourse due to stormwater runoff. Compliance with this provision shall be attained when it is demonstrated that the project's stormwater management plan has considered current BMPs (e.g., those presented in the NJDEP BMP Manual) for applicability to the project in order to achieve the goal of no net increase in stormwater pollutant loads. Implementation of these measures should be successful in achieving 80% removal of total suspended solids loading and therefore meet this goal. The applicant shall not be required to install BMPs which exceed the goal, but, where possible, is strongly encouraged to do so. The applicant must provide economic or other justification where implementation of the plan is not predicted to achieve compliance with the goal of no net increase in stormwater pollutant loads.
(2) 
Nonstructural stormwater management practices shall be utilized prior to the use of structural management measures, unless it is demonstrated that these practices are not feasible from an engineering, environmental or economic perspective on a particular site. Nonstructural measures include elements of site design to protect water quality (e.g., vegetated buffers adjacent to watercourses, limitations on use of impervious surfaces, limitations on site disturbance, use of native vegetation, and requirement of appropriate fertilizer and pesticide use).