2918-25 STORMWATER final 4_1_25.doc.pdf

31 manufactured treatment device, or a catch basin hood) that is designed, at a minimum, to prevent delivery of all solid and floatable materials that could not pass through one of the following: a. A rectangular space four and five-eighths (4.625) inches long and one and one-half (1.5) inches wide (this option does not apply for outfall netting facilities); or b. A bar screen having a bar spacing of 0.5 inches. Note that these exemptions do not authorize any infringement of requirements in the Residential Site Improvement Standards for bicycle safe grates in new residential development (N.J.A.C. 5:21-4.18(b)2 and 7.4(b)1). iv. Where flows are conveyed through a trash rack that has parallel bars with one inch (1 inch) spacing between the bars, to the elevation of the Water Quality Design Storm as specified in N.J.A.C. 7:8; or v. Where the New Jersey Department of Environmental Protection determines, pursuant to the New Jersey Register of Historic Places Rules at N.J.A.C. 7:4- 7.2(c), that action to meet this standard is an undertaking that constitutes an encroachment or will damage or destroy the New Jersey Register listed historic property. § 25-29.8—Safety Standards for Stormwater Management Basins: A. This section sets forth requirements to protect public safety through the proper design and operation of stormwater management BMPs. This section applies to any new stormwater management BMP. B. The provisions of this section are not intended to preempt more stringent municipal or county safety requirements for new or existing stormwater management BMPs. Municipal and county stormwater management plans and ordinances may, pursuant to their authority, require existing stormwater management BMPs to be retrofitted to meet one or more of the safety standards in § 25-29.8C1, C2, and C3 for trash racks, overflow grates, and escape provisions at outlet structures. C. Requirements for Trash Racks, Overflow Grates and Escape Provisions 1. A trash rack is a device designed to catch trash and debris and prevent the clogging of outlet structures. Trash racks shall be installed at the intake to the outlet from the Stormwater management BMP to ensure proper functioning of the BMP outlets in accordance with the following: i. The trash rack shall have parallel bars, with no greater than six-inch spacing between the bars; ii. The trash rack shall be designed so as not to

the BMP outlets in accordance with the following: i. The trash rack shall have parallel bars, with no greater than six-inch spacing between the bars; ii. The trash rack shall be designed so as not to adversely affect the hydraulic performance of the outlet pipe or structure; iii. The average velocity of flow through a clean trash rack is not to exceed 2.5 feet per second under the full range of stage and discharge. Velocity is to be computed based on the net area of opening through the rack; and