2025 06 18 WEH Slope Stability Analysis Letter Report

Memorandum 300 Kimball Drive To: Parsippany, NJ 07054 T: 973.560.4900 F: 973.560.4901 Mark Hoffman / Garden Homes From: Mark K. Seel / Langan Ronald D. Boyer / Langan Info: _____________________ Mark K. Seel, P.E. Professional Enineer NJ Lic. No. 24GE04229500 Adam Yoda / Langan John Cote / Langan Michael Vitello / Langan Ronald D. Boyer, P.E. Date: 14 January 2025 Revised 18 June 2025 Re: Global Slope Stability Study for Building D West Essex Highlands Project West Orange, New Jersey Langan Project No.: 101049801 Professional Engineer NJ Lic. No. 24GE04200300 This memorandum summarizes the subsurface investigations and global slope stability evaluations performed by Langan Engineering and Environmental Services, LLC (Langan) for the eastern portion of the proposed West Essex Highlands development site located in West Orange, New Jersey. The following sections provide a description of existing site conditions, proposed development, subsurface investigations performed, and conditions encountered, our global slope stability analysis and our evaluation regarding slope stability with respect to the associated building construction. EXISTING CONDITIONS AND PROPOSED CONSTRUCTION The subject project site is located on Lot 32, Block 179, and is bounded by Avon Drive and Howell Drive and residential properties to the north, and residential developments to the south, east and west. The focus of the investigations (the “Study Area”) and subsequent global slope stability analysis is the easternmost portion of the site bounded by Howell Drive, Rosemont Terrace and Mayfair Drive to the east. The Study Area is heavily wooded and surface grades slope downward from west to east. There is a 25-foot-wide utility easement that bisects the subject area running in the north-south direction. Site surface grades generally range from approximately elevation (el) 616 to el 450. Typically, the slope in the Study Area ranges from about 2 Horizontal (H): 1 Vertical (V) or approximately 26 degrees from horizontal at its steepest to approximately 6H:1V or approximately 10 degrees from horizontal east of the utility easement. Hard basalt rock outcrops locally, typically 2 feet (ft) to 15 ft tall, have nearly vertical faces. The proposed residential development will consist of the construction of new 4-story structures over structured parking. Based on available site drawings

ft) to 15 ft tall, have nearly vertical faces. The proposed residential development will consist of the construction of new 4-story structures over structured parking. Based on available site drawings prepared by Anderson Consulting