Home » Management Stormwater Management Butte-Silver Bow MS4 Annual Reports 2021 MS4 Annual Report 2020 MS4 Annual Report 2019 MS4 Annual Report 2017 MS4 Annual Report 2016 MS4 Annual Report 2015 MS4 Annual Report Management Program Documents Butte-Silver Bow MS4 Storm Water Management Plan (SWMP) Enforcement Response Plan (ERP) MS4 Stormwater Sampling and Analysis Plan (SAP) Butte-Silver Bow Utilities Web Map Butte-Silver Bow Stormwater Drainage & Outfall Map Program Updates 2023 Stormwater Management Program Changes Presentation 2017-2019 BSB Storm Water Sample Results