1240815StormWaterManagementReport

CASEY & KELLER, INC. LAND SURVEYORS + CIVIL ENGINEERS + PLANNERS N.J. STATE BOARD OF PROFESSIONAL ENGINEERS & LAND SURVEYORS CERTIFICATE OF AUTHORIZATION NO. 24GA27985400 258 MAIN STREET, MILLBURN, NEW JERSEY, 07041 VOICE: 973‐379‐3280 FAX: 973‐379‐7993 STORM WATER MANAGEMENT REPORT 512-516 PLEASANT VALLEY WAY TOWNSHIP OF WEST ORANGE ESSEX COUNTY, NJ Block 154.06, Lots 11 & 12 PROJECT # 1240815 DATE: August 11, 2025 ______________________________________________________ MICHAEL LANZAFAMA, P.E. & P.L.S. NJ REG. # GB 30084

STORM WATER MANAGEMENT REPORT SUMMARY PROJECT LOCATION The project is located at 512-516 Pleasant Valley Way in the Township of West Orange, Essex County, New Jersey. The site is located across the intersection with Greenwood Avenue and about 560 feet to the intersection with the southerly line of Eagle Rock Avenue. The property lies within the Office Building Zoning District. EXISTING CONDITIONS The site is currently occupied by two commercial buildings. One is a One-Story frame dwelling with parking in the rear and the second building a Two story masonry building. This building has also a parking lot on the rear of the property. The site area is 16,242 square feet in size or 0.373 acres. Its frontage on Pleasant Valley Way 124.99 feet, and it has a lot depth of 130.0 feet. It will be serviced with all basic utilities—water, gas, electric, sanitary sewer, and cable, which are provided from underground pipelines and conduits. The area around the site is developed with residential and commercial uses. The property is not impacted by flood plains, and freshwater wetlands have not been observed. TOPOGRAPHY The site slopes from north to south. The highest elevation is approximately 422.0 feet at the most northern corner of the property. The lowest elevation is at approximately 412.0 feet in the most southern corner of the property. SOILS The site contains two soil types. The Soil Survey of Essex County has identified the soils as Urban Land, Boonton, 0 to 8 percent slopes and Boonton - Urban Land, Boonton, 0 to 8 percent slopes. The Natural Resources Conservation Service has classified these soils as being in Hydrologic Soil Group “C”. IMPERVIOUS COVERAGE SUMMARY IMPERVIOUS COVERAGE EXISTING PROPOSED Buildings 2676 SF 3387 SF Drive & Parking 7679 SF 6473 SF Patio 82 SF 0 SF Walk/step 794 SF 1279 SF Misc. 12 SF 80 SF Total 11149 SF 11219 SF Net Decrease 70 SF

SF Total 11149 SF 11219 SF Net Decrease 70 SF 1

STORMWATER MANAGEMENT As with any construction project, stormwater management is an important part of the overall development process. Modern practice is a combination of the site designer’s knowledge and goals in conjunction with the rules and regulations of the local municipality and the New Jersey Department of Environmental Protection (see Hydrology section below). Part of stormwater management is to minimize the use of artificial structures; however, practical considerations of most development sites require a combination of non-structural and structural components. A substantial portion of the existing site contains buildings and bituminous pavement. The entire site drains to the south area where it runs thru a swale to the street on the rear and is collected by the storm system within Beasly Street. Stormwater hydrographs for both existing and proposed conditions for each drainage area, are included in this report. The Township of West Orange requires that stormwater analyses be performed for the 2-year, 10-year, and 100-year storm events, applying reduction factors of 50%, 25%, and 20%, respectively, for major developments. Although this project does not qualify as a major development, these reductions were voluntarily applied to further enhance site performance. The “Natural Resources Conservation Service Method,” as outlined in Technical Release 55 (TR-55), was utilized to size and route stormwater through the proposed drywell system. DISCHARGE SUMMARY The following table shows that the site would produce post-developed runoff rates and volumes that are lower than the site’s existing rates of runoff. The existing and proposed peak runoff rates (Q) from the site are summarized as follows: Site Discharge Summary Peak Detention Flow Subject to Q Q Total Q Frequency Reduction Reduction Existing Allowable Proposed Q Non Disturb 2 - 2020 0.98 0.50 + 0.00 = 0.49 0.43 10 - 2020 1.63 0.25 + 0.00 = 1.22 0.70 100 - 2020 2.97 0.20 + 0.00 = 2.38 1.89 The Site Discharge table shows that the proposed project would result in post-developed runoff rates that are less than or equal to

7 0.20 + 0.00 = 2.38 1.89 The Site Discharge table shows that the proposed project would result in post-developed runoff rates that are less than or equal to the site’s existing runoff rates. The hydrographs for the 2-year, 10-year and 100-year storms do not exceed at any time the pre-developed hydrographs for the same events as required per West Orange’s ordinance. Based upon this analysis, it is our professional opinion that the proposed storm water management system would enhance the existing downstream conveyance systems and meet the required Municipal standards. Calculations supporting these findings constitute the remainder of this report. 2

SOILS

Hydrologic Soil Group—Essex County, New Jersey 74° 15' 40'' W 74° 15' 36'' W 562310 562320 562330 562340 562350 562360 562370 562380 562390 40° 48' 31'' N 40° 48' 31'' N 4517780 4517780 4517770 4517770 4517760 4517760 4517750 4517750 4517740 4517740 4517730 4517730 Soil

4517730 Soil Map may not be valid at this scale. 40° 48' 29'' N 40° 48' 29'' N 562310 562320 562330 562340 562350 562360 562370 562380 562390 Map Scale: 1:424 if printed on A landscape (11" x 8.5") sheet. Meters 74° 15' 40'' W 74° 15' 36'' W N 4 0 5 10 20 30 Feet 0 20 40 80 120 Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS84 Natural Resources Web Soil Survey 7/24/2025 Conservation Service National Cooperative Soil Survey

Hydrologic Soil Group—Essex County, New Jersey MAP LEGEND MAP INFORMATION Area of Interest (AOI) C The soil surveys that comprise your AOI were mapped at Area of Interest (AOI) 1:12,000. C/D Soils Warning: Soil Map may not be valid at this scale. D Soil Rating Polygons Not rated or not available Enlargement of maps beyond the scale of mapping can cause A misunderstanding of the detail of mapping and accuracy of soil A/D Water Features line placement. The maps do not show the small areas of Streams and Canals contrasting soils that could have been shown at a more detailed B scale. Transportation B/D Rails Please rely on the bar scale on each map sheet for map C measurements. Interstate Highways C/D Source of Map: Natural Resources Conservation Service US Routes D

Source of Map: Natural Resources Conservation Service US Routes D Web Soil Survey URL: Major Roads Coordinate System: Web Mercator (EPSG:3857) Not rated or not available Local Roads Maps from the Web Soil Survey are based on the Web Mercator Soil Rating Lines projection, which preserves direction and shape but distorts Background A distance and area. A projection that preserves area, such as the Aerial Photography Albers equal-area conic projection, should be used if more A/D accurate calculations of distance or area are required. B This product is generated from the USDA-NRCS certified data as B/D of the version date(s) listed below. C Soil Survey Area: Essex County, New Jersey Survey Area Data: Version 20, Sep 3, 2024 C/D Soil map units are labeled (as space allows) for map scales