Stormwater Program

Humboldt County Public Works administers a stormwater management program to reduce the discharge of pollutants to the storm sewer systems and associated receiving waters as regulated by the federal Clean Water Act through the National Pollution Discharge Elimination System (NPDES) permit program.

Working Together on the Humboldt Bay
The County of Humboldt is collaborating with the City of Eureka and the Humboldt Community Services District in the development of the Eureka Area Watershed Storm Water Resource Plan (EAWSWRP). The EAWSWRP is a regional storm water planning document that facilitates a watershed-based analysis and planning effort within watersheds that drain to Humboldt Bay. The EAWSWRP is intended to maximize cooperation and collaboration among state, regional, and local agencies, and other stakeholders during the identification, development, and implementation of storm water projects.

Municipal Stormwater Permit and Low Impact Development Standards
In February 2013, the State Water Resources Control Board adopted the current version of the “MS4 Permit” which applies to stormwater discharges from small municipal separate storm sewer systems (MS4s). The purpose of the MS4 Permit is to control the discharge of pollutants to storm sewer systems which ultimately drain to natural waterways. The state has stipulated that the MS4 Permit applies to McKinleyville, the unincorporated Eureka area, and Shelter Cove (County of Humboldt Phase II MS4 Boundary Maps).

The MS4 Permit requires that the County require certain development projects to comply with post-construction stormwater requirements based on “low impact development” standards. These standards are intended to maintain a site’s pre-development runoff characteristics by using design techniques that capture, treat, and infiltrate stormwater on site. These standards will be effective starting July 1, 2015.

The MS4 General Permit specifies two size classes for post-construction requirements. Projects that create and/or replace 2,500 to 5,000 square feet of impervious surface (“small projects”) will need to implement one or more designated site design measures to reduce project site runoff. Examples of site design measures include disconnection of rooftop drainage from impervious areas, tree planting and preservation, rain barrels, vegetated swales, and porous pavement. Projects that create and/or replace 5,000 square feet or more of impervious surface (“regulated projects”) will need to implement site design measures based on more detailed procedures and demonstrate compliance with runoff reduction thresholds. Some projects may be required to construct bioretention facilities. In addition, projects in the larger size category will need to comply with source control measures to minimize the contact between pollutants and stormwater runoff.

Procedures, standards, and specifications for implementing the post-construction requirements of the MS4 Permit are contained in the Humboldt Low Impact Development Stormwater Manual V2.0. This manual will also be used by the Cities of Eureka, Arcata, Fortuna, and Trinidad for compliance with the MS4 Permit. Humboldt LID Stormwater Manual V2.0 and associated documents are available on the North Coast Stormwater Coalition website.

North Coast Stormwater Coalition

Humboldt County participates in the North Coast Stormwater Coalition which coordinates regional storm water management efforts. A toll free regional stormwater hotline operated by the North Coast Stormwater Coalition can be called at 1-707-2STORM2 to report active pollution or other stormwater concerns.

The North Coast Stormwater Coalition works collaboratively with North Coast California county and city governments to reduce stormwater pollution and protect local watersheds. Coalition members include stormwater management staff from the participating Cities of Arcata, Eureka, Fortuna, Ft. Bragg, Trinidad and Yreka, the Counties of Humboldt and Mendocino, and Humboldt State University, as well as representatives of other local, state, and federal agencies, non-profit organizations, tribes, the CA State and Regional Water Boards, consultants, engineers, and interested community members. We are a robust group that meets monthly, with public education and outreach events and workshops occurring throughout the year.

More information is provided on the North Coast Stormwater Coalition website.

Documents for Viewing and Download:

The following State and Federal websites contain technical and regulatory information regarding Municipal, Construction, and Industrial stormwater programs and stormwater pollution prevention resources.

Humboldt Waterways Poster