Salmonid Restoration Federation

Marshall Ranch Flow Enhancement

Background

Since 2013, Salmonid Restoration Federation has been conducting low-flow monitoring in Redwood Creek, a
critical tributary to the South Fork Eel River. The South Fork Eel River is considered one of the highest priority
watersheds in the state for flow enhancement projects. Forested tributaries like Redwood Creek provide refugia
habitat for threatened juvenile coho salmon but suffer from the cumulative impacts of legacy logging and
unregulated water diversions. 
 
With funding from the Wildlife Conservation Board and the California Department of Fish and Wildlife, SRF and
Stillwater Sciences have been exploring the feasibility of various streamflow enhancement opportunities in Redwood
Creek. Stillwater Sciences conducted a feasibility study in a segment of the watershed that helped to identify priority
projects that could improve summer flows.
 
Stillwater Sciences prepared conceptual designs for off-channel rainwater catchment ponds that could improve
water security for individual parcels but would require wide and coordinated participation in order to
measurably improve flows. After much research and reconnaissance, the SRF and Stillwater project team
determined that the greatest opportunity to improve streamflows was to work cooperatively with the Marshall
Ranch, the largest private parcel in the watershed that has been stewarded by the Marshall family since the
1800s and is now fully protected under conservation easement.
 

Marshall Ranch Flow Enhancement Project

SRF and Stillwater Sciences reviewed the public comments that we received during the 2020 Mitigated Negative Declaration public comment period and began exploring the feasibility of potential flow enhancement projects on the Lost Coast Forestland (LCF) property. The LCF is 1,000-acres of recovering forestland in the headwaters of Redwood Creek that was recently acquired and will be managed under a conservation easement dedicated to restoration and recovery goals.
 
On February 25, 2021 SRF hosted an online public meeting to discuss the status of the pending Marshall Ranch flow enhancement MND and some alternative scenarios to achieve our target flow release of 50 gpm. The meeting was attended by over 45 stakeholders including community members, regulatory agencies, the planning department, restoration partners, and grant managers. The recording has been archived on the SRF website so it can be accessible for anyone who was unable to attend. https://vimeo.com/517329746 
The powerpoint presentations are embedded in this video.
 
At this public meeting, Stillwater Sciences presented three alternatives. SRF and Stillwater Sciences spent the last six months conducting topographic surveys, initiating cultural investigations, comparing on-the-ground conditions with LiDAr data, and meeting with CDFW environmental permitting staff. Our project team wanted to understand the potential pond volume that could be stored at the LCF property in order to inform a redesign of the Marshall Ranch pond that would be amenable to community members who objected to the size of the originally proposed 15.3 million gallon pond on the upper terrace of the Marshall Ranch. Additionally, the Lost Coast Forestland property presents an opportunity to improve instream flows for a longer stream reach. 
 
After a preliminary feasibility study on the LCF ownership, it appears that offstream ponds with a total volume of 5.5 million gallons are feasible on the LCF property. Based on this finding, we are now proceeding with a new design on the Marshall Ranch which includes downsized total water storage volume of 10 million gallons in two smaller ponds and several large water tanks. The reduced volume and new pond layout allow for the ponds to be fed with rainfall and gravity diversion from small tributaries, greatly reducing the mechanization of the design.
 
Cumulatively, the Marshall Ranch and LCF projects will result in over 15 million gallons in total water storage and provide the target flow of 50 gpm in mainstem Redwood Creek downstream from Briceland while providing approximately 20 gpm of flow augmentation to an additional several miles of critical aquatic habitat in Redwood Creek upstream from Briceland. We believe that the new design on the Marshall Ranch combined with the proposed project on the LCF property effectively address all of the substantive items raised in the letters of opposition. 
 
After initial discussions with the landowners, neighbors, agency staff, and other stakeholders, Stillwater Sciences has now revising the Marshall Ranch project documents including the 90% Design Plans and a Basis of Design Report and we will be re-submitting a revised MND to the Humboldt County Planning Department later this summer to re-initiate the CEQA approval process.

Marshall Ranch Site Photos


 

 

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