Mill Creek & Palmer Creek Instream Habitat Design

Salmonid Restoration Planning and Assessments

Project ID	1611968197381
Recovery Domains	N Central California Coast
Start Date	05/25/2021
End Date	02/05/2026
Year	2020
Status	Completed
Last Edited	02/17/2026

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Description

This project produced 100% design plans for a series of 40 instream large woody material (LWM) habitat enhancement features containing 204 logs and the introduction of a minimum of 95 new pieces of LWM using accelerated wood recruitment (AWR) techniques. The project reach is defined as the reach of Mill Creek and Palmer Creek within the parcel owned by the cooperating landowner comprising approximately 8,200 feet (1.5 miles) or 35.5 acres of coho salmon habitat in Mill Creek which is tributary to Dry Creek and thence the Russian River in Sonoma County.

FY19 and FY20 funds spent within the appropriate award windows.

Project Benefit

All habitat features are expected to increase the available habitat area under winter and summer flow conditions in both the main channel and off-channel by increasing channel complexity, encouraging pool creation, deepening existing pools by scour, generating additional cover as well as providing velocity refugia during high flows.

Source

Funds

PCSRF

$312,302

In-Kind Donated Labor

$4,114

Report Total:

$316,416

Worksites

1611968197628

Worksite Identifier: 1611968197628
Start Date:
End Date:

Area Description
Main Field Site: Mill Creek and Palmer Creek

Location Information

Basin: Northern California Coastal (180101)
Subbasin:
Watershed:
Subwatershed:

State: California
Recovery Domain: N Central California Coast
Latitude: 38.5852143
Longitude: -122.9407064

ESU

Central California Coast Coho Salmon ESU

Map

Photos

Metrics

B.0 Salmonid Restoration Planning and AssessmentsY (Y/N)

. . B.0.a Planning And Assessment Funding 316,416.00
. . B.0.b.1 Area Encompassed 45.5
. . B.0.b.2 Stream Miles Affected 1.45

. . B.1 Restoration Planning And CoordinationY (Y/N)

. . . . B.1.a Planning and Coordination funding 316,416.25

. . . . B.1.b.11 Engineering/design work for restoration projectsY (Y/N)

. . . . . . B.1.b.11.a

Name of plan implemented
Recovery Plan for Central CA Coast Coho Salmon (NOAA Final Sept 2012) and Flosi, G, Caisley, M. and M. Smelser, 2024, The Use of Large Wood in Stream Habitat Restoration, California Dept. of Fish and Wildlife Fish Bulletin 184. State of California, The Natural Resources Agency

. . . . . . B.1.b.11.b

Description and scope of the plan implemented

The project completed 100% design plans for a series of 40 instream large woody material (LWM) enhancement structures in Mill Creek and Palmer Creek containing 216 logs including 107 logs obtained from well-stocked riparian forest stands using accelerated wood recruitment (AWR) techniques. Although at least three potential backwater habitat restoration sites were developed for the Concept Plan, it was ultimately determined through hydraulic analyses that the proposed backwater habitats were potentially feasible, but an inefficient means to improve shelter and habitat complexity in the project reach. In addition, the hydraulic analysis revealed that the backwater channel habitats would have needed to be deeply excavated in the terrace features identified. The feasibility of excavating to depths of 8 to 10 feet was uncertain owing to the likelihood of encountering bedrock at shallower depths. Consequently, a significant change in emphasis of the design approach shifted from backwater channel habitat (with significant additions of LWM in existing instream habitat) to expanded recruitment of key piece LWM through AWR from adjacent forest stands. Owing in large part to the unparalleled cooperation of the property owner, the design team was able to identify a large number of accessible key piece conifers that could be felled and transported to stable locations in Mill Creek and upper Palmer Creek without significant harm to riparian function in the reach (i.e. shade and future LWD recruitment). The addition of numerous key pieces of LWM as defined in CDFW Fish Bulletin 184 created nodes of enhanced stability around which smaller pieces of LWM could be efficiently incorporated in the overall design plans with engineering for stability in the 100 year design flood. The project will provide the number of key pieces of LWM necessary to meet criteria for "Very Good" conditions per CDFW Fish Bulletin 184. With the addition of these large quantities of LWM, a significant improvement in velocity shelter and habitat complexity can be achieved as determined in the hydraulic model used for this project that far exceeds what might have been possible from creating backwater channels. The net effect of the project when constructed will be very large increases in the amount and quality rearing habitat in a stream reach where habitat utilization by juvenile coho is significant. The project is also expected to significantly improve spawning habitat owing to significant increases in opportunities for retention and sorting of bed sediment.