PB 22 10 Altera 769 LLC Filed Application with Exhibits Final Site Plan Phase 2

III. PROPOSED SITE CONDITIONS The proposed improvements consist of the renovation of the existing office building, modifications to the existing parking lot to satisfy current ADA regulations, the expansion of the rear parking area, and other associated site improvements. The proposed site improvements shall result in an increase in impervious coverage of 20,635 SF (0.47 Ac). The existing drainage patterns on-site shall remain relatively unchanged. Stormwater runoff generated by the roof of the renovated building will remain relatively unchanged. Runoff generated by the portions of the site that are not covered with building shall continue to sheet flow west and be collected by various on-site inlets. An aboveground bioretention basin has been designed to detain stormwater runoff generated by the proposed parking lot, parking lot expansion and surrounding wooded areas in accordance with stormwater reduction requirements set forth under NJAC 7:8 and by the Township of West Orange. The proposed site conditions have been evaluated using the following drainage sub-watershed areas as depicted on the Proposed Drainage Area Maps included within the Appendix of this report: DA-1: This area consists of the wooded area to the northeast of the parking lot expansion. Stormwater runoff generated by this area sheet flows overland where it is ultimately collected by a proposed yard inlet, and conveyed to the proposed aboveground stormwater management basin, where it is detained and released at a controlled rate to the existing stormwater management structure (POI-2). A time of concentration of 18.8 minutes has been calculated and utilized for this drainage area. DA-2 Undetained: This area consists of a portion of the existing rear northern parking area. Stormwater runoff generated by this area sheet flows overland to the west and is collected by a proposed inlet, where is it ultimately conveyed to the existing stormwater management structure (POI-2). A minimum time of concentration of six (6) minutes has been utilized for this drainage area. DA-2A Detained: This area consists of a majority of the rear parking lot expansion area and a portion of the rear wooded area. Stormwater runoff generated by this area sheet flows overland to the west and is collected by proposed inlets and conveyed to the proposed aboveground stormwater management basin.

he rear wooded area. Stormwater runoff generated by this area sheet flows overland to the west and is collected by proposed inlets and conveyed to the proposed aboveground stormwater management basin. Stormwater runoff is then detained and released at a controlled rate to the existing stormwater management structure (POI- 2). A time of concentration of 14.7 minutes has been calculated and utilized for this drainage area. DA-2B Detained: This area consists of a portion of the rear remaining parking lot expansion area, the aboveground stormwater management basin and portion of the rear wooded areas. Stormwater runoff generated by this area sheet flows overland to the west and is collected by a proposed inlet and conveyed to the Altera 769, LLC 5 Revised August 2022 DECPC #2530-99-006