Residual Designation Authority to Address Stormwater Quality Problems in EPA's Pacific Southwest (Region 9)
About
The Clean Water Act (CWA) and related regulations define the specific construction, industrial and municipal stormwater sources that must be authorized by a National Pollutant Discharge Elimination System The national program for issuing, modifying, revoking and reissuing, terminating, monitoring and enforcing permits, and imposing and enforcing pretreatment requirements, under CWA sections 307, 318, 402, and 405. The term includes approved program. permits regulate discharges of pollutants from point sources to waters of the United States. Such discharges are illegal unless authorized by an NPDES permit. (NPDES The national program for issuing, modifying, revoking and reissuing, terminating, monitoring and enforcing permits, and imposing and enforcing pretreatment requirements, under CWA sections 307, 318, 402, and 405. The term includes approved program. NPDES permits regulate discharges of pollutants from point sources to waters of the United States. Such discharges are illegal unless authorized by an NPDES permit.) permit. The CWA also recognizes that other sources may need to be regulated on a case-by-case or category-by-category basis based on additional information or localized conditions. The authority to regulate other sources based on the localized adverse impact of stormwater on water quality through NPDES permits is commonly referred to as the "Residual Designation Authority".
EPA can use its residual designation authority under 40 CFR 122.26(a)(9)(i)(C) and (D) (pdf) to require NPDES permits for other stormwater discharges or category of discharges on a case-by-case basis when it determines that:
- the discharges contribute to a violation of water quality standards,
- are a significant contributor of pollutant to federally protected surface waters, or
- controls are needed for the discharge based on wasteload allocations that are part of "total maximum daily loads" (TMDLs) that address the pollutant(s) of concern.
In addition, designation can be requested by petition.
Water Quality Challenges in two Los Angeles Watersheds - Los Cerritos Channel/Alamitos Bay and Dominquez Channel/Los Angeles/Long Beach Harbor
In response to petitions and a 2018 District Court order, Region 9 is using its residual designation authority to add requirements for certain stormwater sources (based on land use categories) that discharge to these two waterbodies. The final designation is specifically for privately-owned commercial, industrial and institutional (CII) facilities to obtain NPDES permit coverage for stormwater runoff only in these two watersheds. Both watersheds are impaired due to elevated levels of copper and zinc and Total Maximum Daily Loads have been established to define needed reductions of these pollutants to restore water quality and beneficial uses of the watersheds.
EPA is acting under the Clean Water Act (CWA) to designate stormwater discharges from certain privately-owned commercial, industrial and institutional (CII) sites, exclusively within two Los Angeles County watersheds, that are contributing pollutants to impaired surface waters. Once designated, these sites will be required to obtain coverage under a National Pollutant Discharge Elimination System (NPDES) permit.
Region 9 is partnering with the Los Angeles Regional Water Quality Control Board, who is preparing to issue a new NPDES permit to provide coverage for all CII facilities in these watersheds designated by EPA’s action.
Related Documents
EPA's 2024 Final Designation
- EPA 2024 Final Designation Memorandum: Alamitos Bay/Los Cerritos Channel Watershed and the Dominguez Channel and Los Angeles/Long Beach Inner Harbor Watershed in Los Angeles County (pdf)
- Response to Comments: Alamitos Bay/Los Cerritos Channel Watershed and the Dominguez Channel and Los Angeles/Long Beach Inner Harbor Watershed in Los Angeles County (pdf)
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IGP Zinc Loading Totals: Alamitos Bay/Los Cerritos Channel Watershed and the Dominguez Channel and Los Angeles/Long Beach Inner Harbor Watershed in Los Angeles County (xlsm)
Excel file that provides EPA’s estimates for zinc loading from CII sites associated with California’s Industrial Stormwater General Permit (IGP) in these two watersheds.
EPA’s 2023 Revised Preliminary Designation
- EPA 2023 Preliminary Designation Memorandum: Alamitos Bay/Los Cerritos Channel Watershed and the Dominguez Channel and Los Angeles/Long Beach Inner Harbor Watershed in Los Angeles County (pdf)
- EPA Fact Sheet: Proposed Action to Address Stormwater Pollution in Two Los Angeles Watersheds (pdf)
- Hoja informativa de la epa: acción propuesta para abordar la contaminación por aguas pluviales en dos cuencas hidrográficas de los ángeles (pdf)
- Memorandum to File: LA RDA Ports Airports Pollutant Loading Comparison (pdf)
EPA’s 2022 Preliminary Designation
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Modeling Data Used for EPA's Analysis: Proposed Action to Address Stormwater Pollution in Two Los Angeles Watersheds (zip)
Modeling data used in the Preliminary Designation of Certain Commercial, Industrial, and Institutional Stormwater Discharges in the Alamitos Bay/Los Cerritos Channel Watershed and the Dominguez Channel and Los Angeles/Long Beach Inner Harbor Watershed in Los Angeles County. - EPA Fact Sheet: Proposed Action to Address Stormwater Pollution in Two Los Angeles Watersheds (pdf)
- Hoja informativa de la epa: acción propuesta para abordar la contaminación por aguas pluviales en dos cuencas hidrográficas de los ángeles (pdf)
- EPA 2022 Preliminary Designation Memorandum: Alamitos Bay/Los Cerritos Channel Watershed and the Dominguez Channel and Los Angeles/Long Beach Inner Harbor Watershed in Los Angeles County (pdf)
August 2022 Public Workshop
On August 30, 2022, EPA and LA Water Board hosted a public workshop to provide information and solicit comments on the proposed designation and permit. See presentation materials below.
- RDA-CII Public Workshop Presentation (pdf)
- Visit the Los Angeles Regional Water Quality Control Board website to access the workshop recording.
December 2021 Stakeholder Meetings
On December 6 and 17, 2021, EPA and LA Water Board hosted stakeholder meetings to provide information and solicit feedback and comments on the proposed designation and permit. Both meetings covered the same information. See presentation materials below.