Stormwater discharges are generated by runoff from land and impervious areas such as paved streets, parking lots, and building rooftops during rainfall and snow events that often contain pollutants in quantities that could adversely affect water quality. Most stormwater discharges are considered point sources and require coverage by an NPDES permit. The primary method to control stormwater discharges is through the use of best management practices.
Rhode Island, like most states, is authorized to implement the Stormwater NPDES permitting program. EPA remains the permitting authority in a few states, territories, and on most land in Indian Country.
In response to the 1987 Amendments to the Clean Water Act (CWA), the U.S. Environmental Protection Agency (EPA) developed Phase I of the NPDES Stormwater Program in 1990. The Phase I program addressed sources of stormwater runoff that had the greatest potential to negatively impact water quality. Under Phase I, EPA required NPDES permit coverage for stormwater discharges from:
- Medium and large municipal separate storm sewer systems (MS4s) located in incorporated places or counties with populations of 100,000 or more;
- Eleven categories of industrial activity which includes construction activity that disturbs five or more acres of land
Operators of the systems, facilities, and construction sites regulated under the Phase I NPDES Stormwater Program must obtain permit coverage for the stormwater discharge leaving sites.
In RI, the Rhode Island Department of Environmental Management (RIDEM) implements the Stormwater program. Since 1984, RIDEM has been the delegated authority to implement the NPDES program in Rhode Island (referred to as RIPDES).
There are five conventional pollutants
The Phase II Final Rule, published in the Federal Register on December 8, 1999, requires NPDES permit coverage for stormwater discharges from:
- Certain regulated small municipal separate storm sewer systems (MS4s); and
- Construction activity disturbing between 1 and 5 acres of land (i.e., small construction activities).
In addition to expanding the NPDES Stormwater Program, the Phase II Final Rule revises the no exposure exclusion and the temporary exemption for certain industrial facilities under Phase I of the NPDES Stormwater Program and certain exemptions relating to ISTEA . The Phase II Rule also established two potential waivers for small construction activities.
The RIPDES Program amended the RIPDES Regulations and has included Phase II storm water requirements (amended February 5, 2003)
The Multi-Sector General Permit for Storm Water Discharge Associated with Industrial Activities [ LINK
] has been finalized and signed on March 30th, 2006. The permit became effective at midnight May 1st, 2006. The Response to Comments were also issued on March 30th, 2006.
The General Permit for Construction Activity [ LINK ] has been issued and is effective as of September 9, 2003 and will expire at midnight September 9, 2008.
The General Permit for Small MS4s and Industrial Activity [ LINK ] at eligible facilities operated by regulated Small MS4s has been issued and signed on November 14, 2003. The Response to Comments were also issued on November 14, 2003.
Every permit contains these five basic sections, but the contents of sections will vary depending on whether the permit is issued to a municipal or industrial facility and whether the permit will be issued to an individual facility or to multiple dischargers (i.e. a general permit).
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