Decatur, AL Environmental Rules: Erosion Control (2026)

Erosion and sediment control in Decatur sits in the site plan chapter, § 25-163(6). Under § 25-161, any development other than single-family residential built along streets designated collector or above by the long range plan needs site plan approval from the city planning commission before a building permit issues. Under § 25-162, twenty-five copies go to the planning department twenty-one days before the commission meeting, and § 25-163 requires the plan to be prepared and sealed by an Alabama-licensed professional engineer.

The erosion rule itself: construction which disturbs one acre or more of ground surface within the city limits requires a general permit for stormwater runoff control, obtained from ADEM by the owner or developer. A copy of the approved permit goes to the city engineering department before site construction, grading or clearing begins. The owner or developer must also prepare a construction best management practices plan (CBMPP) that follows the Alabama Handbook for Erosion Control, Sediment Control and Storm Water Management on Construction Sites and Urban Areas. The CBMPP describes in detail the silt fences, hay bales, rip rap, siltation basins or other means used for erosion control.

Construction plans must carry a project note requiring contractors to provide erosion control, to prevent fuel or hazardous chemical spills, and to avoid overuse of pesticides, fertilizer or herbicides. Asphalt, petroleum products, sealants and concrete cannot be left on site in contact with stormwater runoff. The public can send comments on a proposed BMP, or report a failing one, to the city engineering department.

The same section ties in drainage. Detention is not required for new sites under one acre or for redevelopment adding less than 2,500 square feet of impervious area. Sites from one to twenty-five acres need detention for a 10-year storm, with calculations for the 25- and 100-year events, and larger sites need a 25-year storm design.

The stormwater chapter reinforces this. Section 19.5-9 requires anyone holding a construction NPDES permit to comply with it and allows the city engineer to demand proof of compliance, and § 19.5-10 gives the city engineer inspection and sampling access to construction sites.