Stormwater Runoff

Stormwater runoff is generated when water from rain or other precipitation flows over land or impervious surfaces (such as paved streets, parking lots, and building rooftops) and does not seep into the ground. As this runoff flows, it accumulates debris, chemicals, sediment, and other pollutants that could harm water quality if it is discharged untreated into our local water bodies.

Stormwater Management (MS4)

Under the 1987 Clean Water Act Amendments, the U.S. Environmental Protection Agency (EPA) developed new stormwater regulations to address storm water that might impact water quality. These new regulations were set up in a two phase National Polluted Discharge Elimination System (NPDES) permitting approach based upon population and are enforced by the U.S. EPA, delegated to most states. The expression Municipal Separate Storm Sewer System (MS4) was given to the permittees.

Regulatory Definition

The regulatory definition of an MS4 (40 CFR 122.26 (b)(8)) is "a conveyance or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains): (i) Owned or operated by a state, city, town, borough, county, parish, district, association, or other public body (created to or pursuant to state law) including special districts under state law such as a sewer district, flood control district or drainage district, or similar entity, or an Indian tribe 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. (ii) Designed or used for collecting or conveying stormwater; (iii) Which is not a combined sewer; and (iv) Which is not part of a Publicly Owned Treatment Works (POTW) as defined at 40 CFR 122.2." In practical terms, operators of MS4s can include municipalities, counties, state and federal departments of transportation, and public universities.

Phase I

Phase I, issued in 1990, dealt with MS4s serving an urban population greater than 100,000 people and in Alabama. There are approximately 750 Phase I MS4s in the United States (US).

Phase II

Phase II, issued in 1999, requires regulated small MS4s in urbanized areas, as well as small MS4s outside the urbanized areas that are designated by the permitting authority, to obtain NPDES permit coverage for their stormwater discharges. The City of Daphne fell into this phase of permitting. There are approximately 6,700 Phase II MS4s in the US.

In Alabama, the Alabama Department of Environmental Management (ADEM) enforces the NPDES MS4 permitting program. In 2012, the City of Daphne was designated by ADEM as an owner/operator of a Phase II MS4. The City received its initial MS4 Phase II Stormwater NPDES permit ALR040039 in 2011. The permit was renewed on October 1 ,2016 and will expire on September 30, 2021.

Phase II - Minimum Control Measures

The intent of the Phase II regulations is to reduce the adverse impacts to water quality and aquatic habitat by the development of a stormwater management program, instituting the use of controls and measurable goals for the following six stormwater related Minimum Control Measures (MCM):

• Public Education and Outreach MCM - The Public Education and Outreach (MCM 1) requires the City to implement and evaluate a public education and outreach program that distributes educational materials to the community or conducts equivalent outreach activities about the impacts polluted discharges on water bodies and the steps that the public can take to reduce pollutants in stormwater runoff to the maximum extent practical.
• Public Participation / Involvement - The Public Participation / Involvement (MCM 2) requires the City to develop, implement and evaluate a public participation program centered on the City's Stormwater Management Program and its annual report. Ongoing activities for public involvement may include advisory councils, watershed associations, committees, stewardship programs and other environmental related activities.
• Illicit Discharge Detection and Elimination (IDDE) - The Illicit Discharge Detection and Elimination (MCM 3) requires the City to develop, implement, enforce, and evaluate a program to detect and eliminate illicit discharges and improper disposal, including spills not under the purview of another responding authority, into the City's regulated MS4 area, to the maximum extent practicable.
• Construction Site Runoff Control - The Construction Site Stormwater Runoff Control (MCM 4) requires the development, implementation, and enforcement of a program to reduce, to the maximum extent practicable, pollutants in any stormwater runoff to the MS4 from construction activities that result in a total land disturbance of greater than or equal to 1 acre and activities that disturb less than 1 acre but are part of a larger common plan of development or sale that would disturb 1 acre or more.
• Post-Construction Stormwater Management - The Post-Construction Stormwater Management (MCM 5) goal is to minimize water quality impacts from new development and re-development sites by ensuring the implementation of proper Best Management Practices and their long term maintenance.
• Pollution Prevention / Good Housekeeping - The Pollution Prevention / Good Housekeeping for Municipal Operations (MCM 6) requires the City to develop and implement a program for pollution prevention and good housekeeping for its municipal operations. It also requires the development and implementation of an employee training program designed to prevent and reduce stormwater pollutants, to the maximum extent practicable, in areas such as parks maintenance, fleet and building maintenance, new construction and land disturbances, stormwater system maintenance, and all other applicable municipal operations.