Section 250-RICR-150-10-8.6 - Stormwater Management Standards and Performance Criteria OverviewA. Applicants for all applicable new and redevelopment projects in the State of Rhode Island are required to meet the eleven minimum standards and comply with the specific performance criteria in §§ 8.6 through 8.17 of this Part. In the case of restoration or retrofitting, deviation from these standards may be appropriate at the discretion of the approving agency.B. All applicable project proposals must include a stormwater management site plan for review by State and local government. The plan must address the minimum standards in §§ 8.6 through 8.17 of this Part.C. When a project's stormwater management system is designed, installed, and maintained in accordance with the requirements of this Part, its runoff impacts will be presumed to be in compliance with applicable state regulatory standards and requirements.D. Unless otherwise noted, all storm events referred to herein are 24 hours in duration and utilize US Natural Resources Conservation Service Type III precipitation distribution. Rainfall amounts for Rhode Island for various return frequencies are provided in § 8.6(E) of this Part and shall be used for design unless otherwise specified.E. Design Rainfall Amounts for Rhode Island: All Rhode Island County rainfall values were obtained from the Northeast Regional Climate Center (NRCC) using regional rainfall data processed by NRCC from the period of record through December 2008. RI County | 24-hour (Type III) Rainfall Amount (inches) |
1-Year | 2-Year | 5-Year | 10-Year | 25-Year | 50-Year | 100-Year |
Providence County | 2.7 | 3.3 | 4.1 | 4.9 | 6.1 | 7.3 | 8.7 |
Bristol County | 2.8 | 3.3 | 4.1 | 4.9 | 6.1 | 7.3 | 8.6 |
Newport County | 2.8 | 3.3 | 4.1 | 4.9 | 6.1 | 7.3 | 8.6 |
Kent County | 2.7 | 3.3 | 4.1 | 4.8 | 6.2 | 7.3 | 8.7 |
Washington County | 2.8 | 3.3 | 4.1 | 4.9 | 6.1 | 7.2 | 8.5 |
F. If the standard or criterion is not used or achieved, a written technical justification that is acceptable to the approving agency must be provided.G. The design practices described in this Part shall be implemented by an individual with a demonstrated level of professional competence, such as a professional engineer licensed to practice in the State of Rhode Island.250 R.I. Code R. 250-RICR-150-10-8.6
Amended effective 11/13/2018