National Pollutant Discharge Elimination System (NPDES)
Regulatory Requirements and Applicable Standards
The Storm Water Phase II Final Rule (see also Storm Water Phase II Final Rule: An Overview) requires the operator of a regulated small municipal separate storm sewer system (MS4) to obtain NPDES permit coverage because discharges of storm water from such systems are considered point sources of potential pollution. MS4s are considered publicly owned or operated point sources because they collect storm water and direct it into discrete conveyances, including roads with drainage systems and municipal streets.
According to the 40 CFR 122.26(b)(8) in the Final Rule, "municipal separate storm sewer means a conveyance or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains):
- Owned or operated by a state, city, town, borough, county, parish, district, association, or other public body (created by or pursuant to State law)...including special districts under State law such as a sewer district, flood control district or an authorized Indian tribal organization, or a designated and approved management agency under section 208 of the Clean Water Act that discharges into waters of the United States;
- Designed or used for collecting or conveying storm water;
- Which is not a combined sewer; and
- Which is not part of a Publicly Owned Treatment Works as defined at 40 CFR 122.2."
EPA categorizes MS4s as either small, medium or large. Regulated small MS4s are automatically designated if they are located in urbanized areas (as defined by the Bureau of the Census). The unincorporated areas of the South Coast east of Bell Canyon as well as the communities of Mission Hills, Vandenberg Village and Orcutt fall into this category. Other small MS4s located outside urbanized areas may be designated on a case-by-case basis by the NPDES permitting authority. The communities of Santa Ynez and Los Olivos have been included in this latter category. All of the areas within these two categories are covered in the County of Santa Barbara Storm Water Management Program.
Requirements for Santa Barbara County
The owner or operator of a Phase II regulated small MS4 is required to submit a Notice of Intent (NOI) to obtain coverage under an NPDES storm water permit. The submitted plan must describe how the regulated entity will identify and implement a range of Best Management Practices (BMPs) into an effective Storm Water Management Program that covers six Minimum Control Measures, evaluation/assessment and reporting efforts, and record-keeping.
The six Minimum Control Measures are:
Click to read Santa Barbara County's Storm Water Management Program. |
