Ames, IA Environmental Rules: Stormwater Management (2026)

Ames adopted Chapter 5B to satisfy its Municipal Separate Storm Sewer System (MS4) permit from the Iowa Department of Natural Resources, requiring a program that controls stormwater runoff, erosion and non-point pollution from new construction and redevelopment (Sec. 5B.1(1)-(5)). The City adopts the Iowa Stormwater Management Manual's sizing criteria, design specifications and best management practices as its own standards (Sec. 5B.1(6)). Coverage is triggered by size: a new development application must meet City stormwater requirements if it disturbs one acre or more of land, or disturbs less land but creates more than 10,000 square feet of impervious cover; a redevelopment application is covered once it creates one acre or more of impervious cover (Sec.

5B.1(8)(a)-(b)). Exemptions cover agricultural activity and additions or modifications to an existing single-family property, and stricter water-quality treatment applies within 1,000 feet of the City's Southeast Well Field and Youth Sports Complex Well Field drinking-water wells. The ordinance is meant to work alongside Chapter 5A erosion control, Chapter 23 Subdivisions, Chapter 28 Utilities and Chapter 29 Zoning, and the stricter of any overlapping requirement controls (Sec. 5B.1(9)). Owners must maintain installed BMPs, keep at least three years of maintenance records, and submit to annual inspections (Sec.

5B.7). Enforcement under Sec. 5B.8 allows civil action with recovery of the City's attorneys' fees, or treats a violation as a municipal infraction punishable by $500 for a first violation and $750 for each repeat violation; the City can also require restoration of disturbed land and place unpaid costs as a lien on the property. Occupancy permits are withheld until all stormwater BMPs are inspected and approved, and decisions may be appealed to the City Council in writing within 20 days (Sec. 5B.8-5B.9).