| Stormwater Regulation |
|---|
| Background |
| Regulatory documents |
Clark County is committed to complying with federal and state regulations to ensure effective stormwater management. The county’s Phase I Municipal Stormwater Permit is issued every five years by the Washington State Department of Ecology and was last renewed on August 1, 2024. It outlines required actions to protect water quality and stream health, inspection programs, mapping, stormwater infrastructure planning, maintenance activities, education and more. Local stormwater codes and the Clark County Stormwater Manual define allowable activities, best management practices, and development standards.
Background
The Clean Water Act of 1972 prohibits pollutant discharge into U.S. waters without a National Pollutant Discharge Elimination System (NPDES) permit. While counties and cities don’t discharge pollutants like industrial sites, they own and manage drainage systems that collect and release polluted stormwater. Clark County’s municipal separate storm sewer system (MS4) directs stormwater into waterways without treatment.
Regulatory documents
Stormwater Management Plan – Clark County's Stormwater Management Plan (SWMP) describes how stormwater and related water quality issues are managed. The plan also describes the county's actions to meet requirements of our Phase I Municipal Stormwater Permit.
NPDES Permit Annual Report – Annual Reporting to Department of Ecology - Clark County is required to report on NPDES permit compliance every March to the Department of Ecology. This report documents the submittals to Ecology for work completed 2024. The document is comprised of the report and attachments.
Stormwater Code and Manual – As part of our work, Clean Water maintains a stormwater manual that guides new development and redevelopment in our community to minimize negative impacts to our waterways and protect groundwater used as drinking water. Clean Water staff work with Clark County Community Development and the Development and Engineering Advisory Board to get input on the regulations. Local stormwater regulations are defined by municipal code and stormwater design manuals. Development standards approved by the state ensure compliance with the county's Phase I Municipal Stormwater Permit. Clark County updated its 2015 stormwater manual in 2021 and is currently in the process of updating the manual by July 2026.
Stormwater Management Action Planning – A Stormwater Management Action Plan (SMAP) is a strategic approach to addressing stormwater runoff impacts on water quality and quantity, particularly within a specific watershed. It focuses on identifying and prioritizing projects and activities to mitigate harmful effects of stormwater. The SMAP process involves assessing existing conditions, identifying problem areas, and developing solutions to protect and improve water bodies. The Washington State Department of Ecology requires Clark County to complete an SMAP as part of the Phase I Municipal Stormwater Permit.
2025-2027 – Lower Salmon Creek Enhanced Maintenance Plan