Stormwater is a valued natural resource, the importance of which is being increasingly recognized through evolving national and state-level permits and greater public awareness. The United States Environmental Protection Agency (U.S. EPA) and California’s State Water Resources Control Board (SWRCB) have tasked local government agencies, such as the County of Humboldt, with administering stormwater management programs to reduce discharge of pollutants to storm sewer systems and associated receiving waters within the County’s municipal separate storm sewer system (MS4) jurisdiction. The SWRCB’s Municipal Stormwater Program webpage notes the “U.S. EPA defines an MS4 as a conveyance or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains) owned or operated by a State.”
However, stormwater management extends beyond the water quality flowing from our rooftops, driveways, parking lots and streets into storm sewer systems, managing stormwater quality discharging from construction sites and commercial and industrial facilities is mandated as well. California’s stormwater permitting program regulates discharges from select industrial facilities (the Industrial General Permit [IGP]), from construction-related activities (the Construction General Permit [CGP]), and areas administered by local government (the small MS4 Permit).
The SWRCB adopted the small MS4 Permit, also known as the Phase II Permit, in 2013. The small MS4 Permit has been amended by the SWRCB several times since its original adoption and is currently under review and is being amended, with reissuance of an updated small MS4 Permit anticipated by 2025.
The small MS4 Permit applies to stormwater discharges from MS4s, where designation as a “small” MS4 is related to a region’s population. The MS4 Permit intent is to provide regulatory consistency across the state to reduce discharge of pollutants to storm sewer systems and the environment. For Humboldt County, the SWRCB has stipulated the small MS4 Permit applies to McKinleyville, the unincorporated Eureka area (Myrtletown, Cutten, Ridgewood Heights, Pine Hill, and Humboldt Hill), and Shelter Cove (County of Humboldt Phase II MS4 Boundary Maps). Humboldt County’s MS4 jurisdiction is anticipated to be expanded to several southern Humboldt County communities with permit reissuance.
The small MS4 Permit includes development of programs which invite public participation, encourage public education, promote public involvement and outreach, detect and eliminate illicit discharges (such as improperly connected septic treatment systems, car wash water, and clean ups of spills and illegal dumping), technical review of property development designs, inspections of facilities, and enforcement of ordinances.
Industrial facilities associated with regulated standard industrial classifications, such as manufacturing, livestock feedlots, transportation, and warehousing, fall under the IGP.
Effective January 1, 2020, California Senate Bill 205 “… requires a person applying to a city or county for a new or renewed business license to demonstrate enrollment in a National Pollutant Discharge Elimination System (NPDES) storm water permit, if such a permit is required.” Cities and counties are mandated to confirm NPDES permit status before issuing a business license.
Humboldt County’s Environmental Health Division is responsible for IGP enforcement on the County level.
Humboldt County’s Department of Public Works recommends reviewing information presented on SWRQB’s Industrial Stormwater Program webpage to learn more about the program and to determine if your business conducts an industrial activity which requires an IGP.
The SWRCB’s Construction Stormwater Program webpage notes “(d)ischargers whose projects disturb one (1) or more acres of soil or whose projects disturb less than one acre but are part of a larger common plan of development that in total disturbs one or more acres, are required to obtain coverage under the General Permit for Discharges of Storm Water Associated with Construction Activity.”
Humboldt County’s Department of Public Works recommends reviewing SWRCB’s Construction Stormwater Program webpage to learn more about Construction General Permit requirements and to access information resources available there. Humboldt County’s Planning and Building and Land Use Departments provide project plan review for project compliance with post-construction and low impact development (LID) requirements and serve as a critical resource for construction permitting and inspections in the unincorporated portions of Humboldt County.
Development projects located within an incorporated city’s MS4 jurisdictional limits are encouraged to contact the relevant city department to discuss Construction General Permit requirements. The 2022 Construction General Permit was adopted by the SWRCB in September 2022.
The small MS4 Permit contains numerous provisions which permittees must address to achieve permit compliance and insure discharged stormwater quality conforms to permit standards. Humboldt County Public Works Water Management Division administers the small MS4 Permit in McKinleyville, unincorporated Eureka (Myrtletown, Cutten, Ridgewood Heights, Pine Hill, and Humboldt Hill), and Shelter Cove. Water Management works in collaboration with Humboldt County Road Maintenance to maintain water quality discharged from County-maintained roads and water conveyance infrastructure.
In addition to requirements for regular facility and MS4 infrastructure inspections, and maintaining MS4 maps, the small MS4 Permit includes public education, outreach, involvement and participation requirements.
Inspections and Cleanups
Small MS4 Permit requirements and the necessity for functional MS4 infrastructure results in regular inspection of County facilities, streets and stormwater infrastructure, and private development. County personnel also respond to spills and illegal dumping inside and outside of the MS4 jurisdiction.The public can assist with preservation of valuable County of Humboldt resources and protection of our natural resources through timely reporting of spills and dumping (call 707-445-7421 to report spills or dumping), but even more importantly, by insuring that pollutants are disposed properly – it is expensive to clean up dump sites, especially if hazardous waste materials are dumped.
The Humboldt Waste Management Authority, located at 1059 West Hawthorne Street in Eureka, is the ideal location to dispose of unwanted items, they even accept hazardous waste!
Public Education, Outreach, and Participation
North Coast Stormwater Coalition
Humboldt County is a member of the North Coast Stormwater Coalition (NCSC), which coordinates regional stormwater management efforts and serves as a means for small MS4 permit public education, outreach, and participation requirements fulfillment by NCSC members.
The NCSC is an alliance of regional county and city governments collaborating to reduce stormwater pollution and protect local watersheds. Coalition members include stormwater management staff from the Cities of Arcata, Eureka, Fortuna, Ft. Bragg, Trinidad and Yreka, the Counties of Humboldt and Mendocino, and California Polytechnic State University-Humboldt, as well as representatives of other local, state, and federal agencies, non-profit organizations, tribes, the State and Regional Water Boards, consultants, engineers, and interested community members. The NCSC a robust group that meets quarterly, with public education and outreach events and workshops occurring throughout the year.
Visit the NCSC website for links to LID resources, the Low Impact Development manual version 3.0, stormwater educational resources, and NCSC member contact information.
Many Humboldt County groups and residents make efforts to keep Humboldt free of litter and other pollution, and they deserve a note of gratitude. Volunteer efforts promote a healthy environment for County residents and visitors to enjoy and experience. An incomplete listing of groups who step up for our community includes:
The PacOut Green Team leads regular volunteer cleanup efforts locally and results of their efforts reduces litter impacts on our environment.
Eel River Cleanup Project – a southern Humboldt volunteer litter removal group
There are also numerous County residents who show initiative and dedication to our community by cleaning up litter encountered during their daily activities, and Public Works wants these folks to know their efforts are appreciated. Thank you to those whose commitment extends to the community at large.
Pollutants of Concern
When many people visualize pollution impacts cigarette butts, litter, or a spilled material like gasoline or motor oil immediately comes to mind, but the small MS4 Permit expands the definition of pollution to include items such as sediment, soapy car wash water, pet waste, wastes from mobile cleaning and pressure washing operations, green waste, fertilizers, pesticides and herbicides. When these pollutants enter the MS4, and eventually Humboldt’s scenic natural waterways, Humboldt Bay, and the Pacific Ocean, the impact of these pollutants can lead to a reduction in water quality that may harm wildlife or the ability of residents and visitors to enjoy Humboldt County’s natural resources. It’s easy, just stop throwing cigarette butts out of the car window and “Pack Your Trash”.
Education is a primary component of the small MS4 Permit because awareness of pollution generating activities allows for behavior changes that can reduce pollution input into the MS4 and our water and lessen the amount of resources dedicated to elimination of pollution.
The small MS4 Permit contains stormwater education and training requirements for County personnel, construction site operators, the general public, and our youth. Links to stormwater education resources are included below.
- Education and the Environment Initiative (EEI) Curriculum. Includes a program overview and links to downloadable curriculum files and training opportunities for teachers.
- Project WET activities are designed to engage students of all ages – in formal and non-formal education settings – in the study of water through interactive simulations, use of models and reality-based scenarios.
- Storm Water Program - Public Education and Outreach – education resources presented by the SWRCB.
- National Menu of Best Management Practices (BMPs) for Stormwater-Public Education – education resources presented by the U.S. EPA.
Post-Construction Stormwater Management
Low Impact Development
The small MS4 Permit mandates certain development projects comply with post-construction stormwater requirements based on LID standards. LID standards are intended to accommodate a site’s pre-development precipitation runoff by incorporating design techniques which capture, treat, and infiltrate stormwater onsite. These standards came into effect July 1, 2015.
The small MS4 Permit specifies two development project size classes mandating post-construction water management requirements. Projects creating and/or replacing 2,500 to 5,000 square feet of impervious surface (“small projects”) are required to implement at least one site design measure to reduce project site runoff, as described in the LID Stormwater Manual for Humboldt County. An impervious surface is a barrier (such as pavement) which prevents the soil’s natural ability to absorb and infiltrate stormwater. Impervious surfaces include, but are not limited to: roof tops, walkways, patios, driveways, parking lots, storage areas, impervious concrete and asphalt, and any other continuous watertight pavement or covering. Examples of site design measures include disconnection of rooftop drainage from impervious areas, tree planting, rain barrels, vegetated swales, and porous pavement.
Projects creating and/or replacing 5,000 square feet or more of impervious surface (“regulated projects”) are required to implement site design measures based on more detailed procedures and are required to demonstrate compliance with runoff reduction thresholds. Some projects may be required to construct bioretention facilities to promote infiltration of stormwater, while other projects in the larger size category will need to employ source control measures to minimize the contact between pollutants and stormwater runoff.
Procedures, standards, and specifications for implementing small MS4 Permit post-construction requirements are contained in the Humboldt Low Impact Development Stormwater Manual V3.0. This manual is also used by the Cities of Eureka, Arcata, Fortuna, and Trinidad for compliance with the small MS4 Permit. Humboldt LID Stormwater Manual V3.0 and associated documents are available on the North Coast Stormwater Coalition website.
Low Impact Development for Existing Sites
LID measures can, and are encouraged to be, incorporated into existing sites to enhance stormwater retention and infiltration onsite, with LID measures often being considered not only beneficial to water quality, but also attractive assets to a site. Site design measures include tree planting, rain capture and storage for later use, directing rooftop drainage systems to discharge to vegetated areas, and incorporation of permeable driving surfaces, such as driveways constructed using pavers which allow for infiltration of stormwater.
Working Together on the Humboldt Bay
The County of Humboldt, the City of Eureka, and the Humboldt Community Services District collaborated to develop the Eureka Area Watershed Storm Water Resource Plan (EAWSWRP), a regional stormwater planning document facilitating analysis and planning efforts within watersheds discharging 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 stormwater projects.
Documents for Viewing and Download
- County of Humboldt Phase II MS4 General Permit Boundary Maps
- Storm Water and the Construction Industry - Best Management Practices Poster
- Humboldt Low Impact Development Stormwater ManualV3.0
- North Coast Stormwater Coalition Low Impact Development recommended Plant List for Humboldt County
The following State, Federal and Association websites contain technical and regulatory information regarding Municipal, Construction, and Industrial stormwater programs and stormwater pollution prevention resources.