The New Jersey Department of Agriculture regulates the disturbance of soil exceeding 5,000 square feet of surface area for a variety of purposes. Elevations range from a low of approximately 140 feet above sea level in the southeastern corner of the Township near South Valley Road, to a high of approximately 620 feet along the ridge of the first Watchung in the area between Essex County Park and Ridge Road. West of this ridge the elevation dips to a low of approximately 360 feet around Crystal Lake and 300 feet around Orange Reservoir. A series of peaks located west of this valley reach heights ranging between 550 and 630 feet. Topography and areas of steep slopes are shown on Figure 4 .
Surface waters flow through the two valleys of West Orange.
The east branch of the Rahway River and the north and south branches of Wigwam Brook dominate the eastern border of the Township. Small segments of Canoe Brook and Bear Brook extend into the Township along the western boundary. Cable Lake and Crystal Lake are located along the ridge of the first Watchung. The 100 year floodplains in West Orange follow the branches of the Rahway River, Peckman River, and Wigwam Brook. One Hundred year floodplains also surround Orange Reservoir, Lake Vincent, Crystal Lake, Cable Lake and a small area of Turtle Brook adjacent to Northfield Avenue, west of Rock Spring Avenue.