Section 250-RICR-150-10-8.34 - Quantity Control - Underground Storage DevicesA. Conveyance 1. Outfalls to the ground surface, where needed, shall be constructed such that they do not increase erosion by discharging near the stream water surface elevation or into an energy dissipating step-pool arrangement.2. An emergency overflow system shall be designed to convey flows larger than the 100-year storm or to divert water in case system fails for any reason.B. Design1. Capacity and discharge rate shall depend on the CPv and Qp requirements. Storage is a function of geometry of the structure, which shall be provided by the manufacturer.2. Sufficient maintenance access points (manholes) shall be incorporated in design to facilitate easy maintenance. Placement shall, at a minimum, occur near the intake and another at the outlet end of the system. The number of manholes depends on maintenance methods used.3. The design shall address implications of the depth to groundwater at the site. A high water table can cause structures to displace due to uplift forces if not designed correctly. Anti-floatation calculations are required when system designed below the water table.C. Maintenance 1. Periodic inspections of the inlet and outlet areas to ascertain correct operation of system and to clean materials trapped on grates protecting catch basins and inlet area.2. Sediment shall be removed from the system when the sediment volume exceeds 10% of the total vault volume.250 R.I. Code R. 250-RICR-150-10-8.34
Amended effective 11/13/2018