25 10 28 Slope Stability Review

Chairman and Members of the West Orange Planning Board Application No. PB24-01, West Essex Highlands, LLC, Warner Road, Block 179, Lot 32 Review of Applicant’s Engineer’s Slope Stability Analysis Reports, the Objector’s Engineer’s Response Reports; and the Applicant’s Engineer’s Rebuttal Report October 28, 2025 Page 4 of 21 PROJECT UNDERSTANDING General This section of the Memorandum describes our review of the proposed construction features as they relate to the evaluation of the slope stability of the ridge in the area of Building D. Our description is based on the interpretation of the drawings submitted for Planning Board Review and included in the CME files as Planning Board Engineer. These are in addition to the Applicant’s and the Objector’s reports and correspondence related to the slope stability and stormwater management submittals as referenced above. We have attached a copy of Langan Drawing entitled “Investigation Plan” for use in understanding the discussion in this memorandum. We have added markup notes using Acrobat Tools with references to the discussion in the text to assist the readers. Proposed Building D We understand that the building design is at a preliminary phase. Our review of the reference Architectural Drawings (Reference 5A) and the Preliminary and Final Site Plan (Reference 5C) indicate the following considerations for this evaluation of the slope stability issues raised by the Applicant’s and Objector’s Engineers: 1. Building Footprint Layout: The footprint of the proposed Building D consists of 2 parallel end sections with a center segment angled at approximately 40 degrees from the alignment of the end sections. The centerline alignment of the building roughly follows the line of the ridge. The nearly uniform width of the footprint is 80 feet. The length of the southern section is approximately 200 feet, the central section is approximately 405 feet and the northerly section of the footprint is approximately 220 feet. The overall length of the building, measured along a line drawn between the centers of the north and south end walls, is approximately 800 feet. 2. Basement Floor Levels: We understand that the uniform first residential floor level is Elevation 618 feet. We understand that the lowest building floor grades are for the parking levels under the building. Our review of the Preliminary & Final Site Plan indicates

idential floor level is Elevation 618 feet. We understand that the lowest building floor grades are for the parking levels under the building. Our review of the Preliminary & Final Site Plan indicates that the garage level on the northern entrance will be +606 feet which is 3 to 4 feet below existing grade along the north building wall and approximately 9 feet above the top of rock encountered at Langan test boring NLB-4. The proposed parking entrance on the south side of the building is shown at elevation 582 feet which is approximately 14 feet below the existing grade at the entrance. The high point of the ridge is near Boring No. LB-3.