On July 16, 2024 the Rhode Island Department of Environmental Management (RIDEM) issued the final renewal of the Rhode Island Pollution Discharge Elimination System (RIPDES) Multi-Sector General permit for Stormwater Discharges from Industrial Activity (MSGP) and established an effective date of September 1^st, 2024. This permit has a 5-year term and replaces the 2019 MSGP, which expired on May 2^nd, 2024.

The RIPDES 2024 MSGP (2024 MSGP) includes new or modified requirements, and thus differs from the RIPDES 2019 MSGP in several ways. These changes are a result of EPA’s recent 2021 MSGP issuance (for consistency), and lessons learned during the RIPDES 2019 MSGP term.

Facilities need to act fast. The new permit has several significant changes to monitoring requirements, Best Management Practice (BMP) obligations, and fundamental requirements (such as recordkeeping retention, electronic reporting, etc.). Stormwater Management Plans (SWMPs) will inevitably need to be reviewed and updated; longer term strategies for sampling and responding to exceedances need to be considered, especially for new metal sampling requirements as these are notoriously difficult to meet.

Summary of Changes

One of the main changes included by RIDEM in the 2024 MSGP is the addition of Indicator Monitoring as a new monitoring category, which mandates a permittee in the applicable industry sector to monitor for Enterococcus bacteria and copper, as these contaminants may be difficult to eliminate completely from stormwater.

Another notable change in the 2024 MSGP is the inclusion of requirements to minimize stormwater impacts from major storm events. This requirement mandates a permittee to implement structural improvements, enhanced/resilient pollution prevention measures, and/or other mitigation measures to minimize the impacts of major storm events such as hurricanes, storm surge, extreme/heavy precipitation, and flood events. The permit provides guidance on how to determine the risk level based on the facility’s location.

The 2024 MSGP has substantial updates to the new Benchmark Monitoring requirements as follows:

• Addition of Sector-Specific Benchmark Monitoring Requirements for Metals for Transfer Stations under Sector P: Facilities regulated under Sector P
  • Land Transportation and Warehousing, including transfer stations, and engaged in the temporary storage and/or transfer of solid waste are required to monitor for aluminum, lead, and zinc in addition to the Total Suspended Solids (TSS) and Oil and Grease (O&G) benchmark “universal” parameters applicable to all facilities.
• Addition of Sector-Specific Benchmark Monitoring Requirements for Polychlorinated Biphenyls (PCBs) to Sector N
  • Scrap Recycling and Waste Recycling Facilities engaged in the processing of construction and demolition (C&D) debris.
• Enhancement to O&G benchmark monitoring requirements for Sectors I, M, N, P, Q, and R
  • Although O&G is required to be monitored by all regulated sectors, as an universal benchmark parameter; RIDEM determined that these sectors are significantly more likely to handle O&G pollutants and contain O&G in their run-off discharges, as such, these sectors are required to monitor for O&G just in the case universal benchmark parameters, change in the future.
• Reduction in Antimony benchmark for facilities regulated under subsector G2;
  • The benchmark limit changed from 0.64 mg/L to 0.45 mg/L to comply with the most recent Freshwater Acute Water Quality Criteria for Antimony contained in the RI Water Quality Regulations (250-RICR-150-05-1).
• Increase in Cyanide Saltwater for facilities regulated under Sector K.
  • The benchmark value increased from 0.001 mg/L to 0.005 mg/L to match the Cyanide Minimum Detection Limit of 0.005 mg/L.
• Removal of Magnesium and Iron benchmark monitoring requirement
  • Magnesium benchmark removal applies to facilities regulated under Sector K – Hazardous Waste Treatment, Storage, or Disposal; and Iron benchmark removal to facilities regulated under sectors C1, C2, E2, F2, G2, H1, L2, M1, N1, O1, Q1, R1, and AA.

In addition to the changes mentioned above, the new permit included some revisions and corrections to clarify existing requirements, as listed below:

• Clarification in the language for the “Data not exceeding benchmark” and “Data Exceeding Benchmarks” sections.
• New requirements for the Level 3 Corrective Actions Reports.
• Addition of “Pavement Wash Water” as a new allowable non-stormwater discharge, under certain restrictions. Similar requirements will now apply to the discharges of building washdown/power wash water.
• Clarification on monitoring requirements addressing that monitoring applies regardless of whether the qualifying rain event or snowmelt monitoring event occurs during business hours.
• Elimination of the option to automatically transfer a permit to a new owner.
• Increase the recordkeeping requirement from three to five years.
• All submissions of required reports or documentation must be done electronically using NeT-MSGP via EPA’s Central Data Exchange (CDX) or Net-DMR.
• Addition of requirements to address the use of Per- and Polyfluoroalkyl Substances (PFAS) exposed to stormwater. The 2024 MSGP requires permittees to evaluate whether their facility uses or has historically used any products containing PFAS, to identify all PFAS containing materials, and to implement PFAS BMPs and pollution prevention strategies.
• The antecedent dry period was reduced from 72 to 48 hours, to provide permittees with additional opportunities to sample and more flexibility to comply with quarterly visual assessment and monitoring requirements.
• SWMPs must be uploaded as part of the Notice of Intent (NOI) submission, weblinks are no longer an option to comply.

Key Timelines

If your facility was covered under the 2019 RIPDES MSGP, a complete NOI must be submitted to RIDEM within ninety (90) calendar days from the effective date of the 2024 MSGP (by November 30, 2024). Prior to submitting an NOI, the facility must update and implement their SWMP to comply with the requirements of the new permit.

Trinity is tracking the implications of this new permit closely. If you would like to discuss the new permit requirements and how they may impact your facility, please email Mayra Durante Cotes or call 508.273.8600.