At their September 8, 2022, meeting, the California Coastal Commission gave their approval to Arcata’s plan to update and maintain our wastewater treatment facility. The permit allows operation of our sewage plant for a period of 30 years, through 2052 — with specific conditions.
And the conditions for continued operation are very clear.
- The City of Arcata has five years to come up with a plan to “identify a suite of
strategies necessary for protecting, relocating, or otherwise adapting [the
Wastewater Treatment Facility] as necessary to maintain safety from
flooding and other coastal hazards in order to minimize risk and assure stability
and structural integrity and to ensure protection of coastal resources over the longterm (at least through 2100).” It is pretty well generally acknowledged that sea level rise will continue, and that all of the bay-front where the Wastewater Treatment Facility is located will certainly be under water. So this plan, due in five years, is not really about protecting or adapting. The plan must be about relocation.
- Every two years, Arcata will submit a report about water elevations — monthly figures, temporary flooding, King Tides, etc. — as well as to report on how the City is progressing with regard to “adaptation planning” as specified in Condition 4 (above).
- The metal bridge over Butcher Slough has to be made quieter. This is the bridge on the main Humboldt Bay trail, just south of the Marsh Interpretive Center. [Hooray! I hate the sound of that bridge. It was a thoughtless design.]
As Arcata citizen Gregory Daggett has been attempting to tell the City Council and Planning Commission, again and again, time after time in his 3-minute impassioned presentations during the oral comment periods. What he says is:
If a person believes that the Coastal Commission has given their full approval to our current wastewater treatment plant location, they either have not read the Coastal Commission report — or else are specifically choosing to ignore it.
Because, in essence, what the Coastal Commission is saying is that the City has to figure out where the plant will be moved to — and has to figure this out within the next five years.
The plant will definitely be upgraded with taller dikes, so that it can withstand higher bay-water heights and what will become regular higher King Tide events. That we know for sure. [When the dike height is raised the width of of the base of the dikes can only be extended on the inside — the base of the dikes cannot encroach any further into the bay.]
Condition 4 clearly states that the City must “identify a suite of strategies necessary for protecting, relocating, or otherwise adapting” the Wastewater Treatment Facility to accommodate conditions “over the longterm (at least through 2100).” Well, to protect the plant through 2100, the dikes might have to be feet higher than what they are now. Is that an engineering possibility? Or does Condition 4 tell us that we need to be looking at re-locating our sewage treatment plant — and that we need to figure out within the next five years just where it’s going to be.
Here in Humboldt we have a greater degree of expected sea level rise than anywhere on the west coast of North America. Based on historical data, it is projected to be about 50% to double that of other regions. Why? Because of tectonic plate movement, our base-level land is subsiding — getting lower. For every inch or foot of sea level rise, the land here is losing elevation at more or less the same rate, thus doubling the height (relative to the land) of the sea level rise.
The City of Arcata is actively engaged in working on this five-year plan. From the City’s Wastewater and Water Infrastructure Planning FAQ page
The City’s 2022/23 budget includes funding for design and permitting of levee augmentation. The City was also recently awarded FEMA funding for the Wastewater Treatment Facility Levee Expansion Project to see this project through to construction. Staff anticipate levee augmentation to be completed in the next five years.
Design of Phase II of the AWTF upgrade project is currently on hold at the request of the State Water Board. The State Water Board has requested that the City explore additional opportunities for long-range planning for the AWTF and has provided technical assistance for a feasibility study which will examine a) potential for alternative/additional siting for wastewater treatment facilities, b) continued use of the existing treatment facility location beyond the Phase I design life, and c) capacity for future growth. This feasibility study is anticipated to commence this summer [Summer 2022?] and be completed by the end of 2023.
The original documents from the Coastal Commission hearing are below.
The PDF documents are separated into the topics of interest, and are arranged with the Summary of the Staff Recommendation at the start, then the more specific sections, and then the full documents at the end. Click on an item to go to that topic.
Summary of the Staff Recommendation
Specific Conditions of Approval Conditions 4, 3, 2, and 14
Specific correspondence City of Arcata, Humboldt Baykeeper
The full documents from the Coastal Commission
For additional information
Please see these articles on this website:
Sea Level Rise articles
Fred Weis speaks to the Planning Commission on Sea Level Rise – January 10, 2023
Sea Level Rise – the basics from May 2022
U.S. Coastal Communities underestimate Sea Level Rise dangers
From the Humboldt Baykeeper website:
Sea Level Rise
Humboldt Bay gets glimpse at future sea level rise
The City of Arcata’s website:
The page on Sea Level Rise & King Tides
FAQs: Wastewater and Water Infrastructure Planning – August 2022
Wastewater Treatment Facilities Improvements Project
Photos of King Tide conditions at the Arcata Marsh / Wastewater Treatment Facility
These photos are from the City of Arcata website article on King Tides. The photos are of the King Tide of January 11-12, 2020. Tide height is listed at 8.5 feet.
Photo credits to HSU Photographer Kellie Jo Brown and Pilot Dave Marshall.
Summary of the Staff Recommendation
5 pages. Pages 1-5 from the main report.
Specific Conditions of Approval
Condition 4: Coastal Hazards Adaptation and Implementation Plan [CHAIP].
This is requirement to figure out Arcata’s wastewater treatment plans through the year 2100.
“The CHAIP shall identify a suite of strategies necessary for protecting, relocating, or otherwise adapting the development authorized by CDP 1-20-0711 as necessary to maintain safety from flooding and other coastal hazards in order to minimize risk and assure stability and structural integrity and to ensure protection of coastal resources over the longterm (at least through 2100).”
2 pages. Pages 12-13 from the main report.
Condition 3: Coastal Hazards Monitoring and Adaptation Reporting.
Every two years, Arcata will submit a report about water elevations — monthly figures, temporary flooding, King Tides, etc. — as well as to report on how the City is progressing with regard to “adaptation planning” as specified in Condition 4 (above).
1 page. Page 11 from the main report.
Condition 2: Duration of Authorization.
The approval is for 30 years, through September 2052.
“The project … is thus interim and temporary, and is permitted for the time frame identified in order to provide a reasonable period of time for the Permittee to evaluate future risk of coastal hazards as influenced by sea level rise and plan, develop, and implement any necessary responses to coastal hazards including adaptation or relocation alternatives, to ensure minimization of risk in the long term….”
1 page. Pages 11-12 from the main report.
Condition 14: Noise Reduction Plan for Increased Use of Metal Bridge Over Butcher
1 page. Pages 23-24 from the main report.
Full conditions of approval
16 pages. Pages 9-24 from the main report.
Letter from the City of Arcata. 2 pages. Pages 2-3 from the Correspondence Report.
Letter from the Humboldt Baykeeper. 3 pages. Pages 5-7 from the Correspondence Report.
Signed by Humboldt Baykeeper, Northcoast Environmental Center, Environmental Protection Information Center, Coalition for Responsible Transportation Priorities
The full documents from the Coastal Commission
The main report. 91 pages.
Exhibits: Maps, engineering documents, etc. 88 pages.
Correspondence: 10 pages.
The California Coastal Commission website page that includes the September 2022 agenda:
Thursday, September 8, Item 12a:
Application No. 1-20-0711 (City of Arcata, Humboldt Co.)