2026 02 12 Crestmont CC and Eagle Rock Ave Stormwater Management Report

Memorandum 300 Kimball Drive Parsippany, NJ 07054 T: 973.560.4900 F: 973.560.4901 To: Mark Hoffman/ Garden Homes From: Adam Yoda / Langan Bhumi Peer / Langan Info: Michael Vitello / Langan Date: 25 August 2025 Revised: 12 February 2026 Re: Stormwater Management Field Testing Results Eagle Rock Ave & Oval Road Improvements 750 Eagle Rock Avenue West Orange, New Jersey Langan Project No.: 101049802 This memorandum presents the results of the field investigation and associated tube permeameter testing performed by Langan Engineering and Environmental Services, LLC (Langan) for the proposed Eagle Rock Ave and Oval Road road widening project site in West Orange, New Jersey. The elevations given in this memorandum are referenced to the surface contours provided in the drawing entitled “Right of Way & Partial Site Survey” dated 11 February 2026, prepared by Langan. The proposed stormwater management system information provided in this memorandum is referenced to the drawings entitled “Partial Grading Plan” dated 12 February, 2026, prepared by Langan. PROJECT DESCRIPTION The site is located immediately south of Eagle Rock Avenue between Laurel Avenue and Wakeman Street in West Orange, New Jersey. The site is currently occupied by wooded areas, landscape areas and paved areas associated with the Crestmont Country Club (CCC). Surface grades vary across the proposed project site, typically sloping downward from elevation (el) 570 at the existing parking area to el 530 at Eagle Rock Avenue. The proposed road widening project will also include the construction of site features at the CCC property. The proposed new site features will include additional parking lots, new roadways, site retaining walls and two (2) stormwater bioretention basins. Our field investigation was performed to support the design of the stormwater management systems for the project. FIELD INVESTIGATIONS The stormwater field investigation included excavating exploratory profile test pits under full-time observation of Langan and performing laboratory tube permeameter tests. The profile test pit locations and proposed target elevations were identified by Langan during the field investigation.