M_ZB 15 N Edgewood Avenue Memo 1

AN EQUAL OPPORTUNITY EMPLOYER www.westorange.org 3.8 The project proposes to increase impervious coverage and a stormwater management system (in the form of one drywell with an open grate is illustrated on the Site Plan. Applicant’s professional must provide calculations demonstrating that the drywell has been adequately sized to accommodate runoff from the tributary drainage area for 6 inches that is closed to the 25-year storm; 3.9 In order to confirm that the drywell will drain within 72 hours, adequate soil permeability results documenting the depth to the seasonal high groundwater table (SHGW), certified soil log(s) or percolation test(s) at the location of the drywells need to be provided. Should test results be unfavorable, Applicant’s Professional will need to provide an alternative means to address and manage stormwater; 3.10 The plan shows two (2) drywells with an open grate while the detail shows an inspection port. The drywell should have a solid cover to prevent pollutants in stormwater runoff seeping into the ground. Drywell is not to be connected to non- rooftop sources of runoff; 3.11 It is recommended that the drywells be provided with an overflow pipe and be connected to the existing roof leader pipe that daylight at the granite block curb; 3.12 The plan provides calculations for the drywells for 3 inches. It is recommended that 6 inches is used to approximate the 25-year storm; 3.13 The Applicant’s professional is responsible for ensuring the effectiveness of proposed drywell and provide sufficient regular oversight during its construction;