Mattole Headwaters Flow Enhancement Project


SCH Number
Lead Agency
Humboldt County
Document Title
Mattole Headwaters Flow Enhancement Project
Document Type
MND - Mitigated Negative Declaration
Present Land Use
LU: timberland, rural community center, residential estates, res ag, Z: Timberland production zone & unclassified

Document Description
Note: Review Per Lead This project will address impacts of past land management, climate change and drought in the Mattole River at a scale needed to restore summertime stream flows in the headwaters. Since 1999 a pattern of low summertime flows in the Mattole River headwaters has caused the river to dry up in some reaches, leaving disconnected pools and poor water quality in the remaining reaches. This prolonged-dry season low-flow pattern has had devastating impacts on the already threatened native salmon populations in the Mattole, for which the headwaters are the most critical spawning and rearing grounds. While measurable streamflow improvements have been made through the successful storage and forbearance program, restoration of ground and surface water hydrology is also needed to achieve drought resilience. Several of the fish-bearing tributaries in the Mattole headwaters that experience extreme low to no flows do not have any human development or diversions of any kind and therefore addressing land use impacts is the only strategy available for improving flows. To address the situation, Sanctuary Forest Inc. is planning to conduct a flow enhancement/restoration project in the Mattole River headwaters (project). The project objectives include improved groundwater recharge/storage and enhanced summer streamflow along with increased riparian vegetation and associated fish and wildlife benefits in the upper Mattole River and its tributaries. The project has been designed to increase the streambed elevation and promote the formation of complex meandering stream and wetlands. Note: See MND for full project description.

Contact Information
Holly Merrifield
Humboldt County
3015 H Street
Eureka, CA 95501

Phone : (707) 268-3703


40°02'26"N 123°56'49"W
Cross Streets
Briceland Thorne Rd
Total Acres
Parcel #
215-172-003-000 et seq.
Whitehorn ES
Upper Mattole River and tributaries
Other Location Info

Notice of Completion

Review Period Start
Review Period End
Development Type
Other (restoration/flow enhancement)
Local Action
Other Action
Project Issues
Aesthetic/Visual Agricultural Land Air Quality Biological Resources Geologic/Seismic Minerals Public Services Traffic/Circulation Wetland/Riparian Wildlife
Reviewing Agencies
Cal Fire California Department of Parks and Recreation Caltrans, District 1 Department of Conservation Department of Fish and Wildlife, Marine Region Department of Fish and Wildlife, Region 1E Department of Water Resources Native American Heritage Commission Office of Historic Preservation Regional Water Quality Control Board, Region 1 Resources Agency State Lands Commission State Water Resources Control Board, Division of Drinking Water State Water Resources Control Board, Division of Water Quality State Water Resources Control Board, Division of Water Rights
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