McGinnis Creek Instream Habitat Enhancement Project

McGinnis Creek Instream Habitat Enhancement Project

This initiative is a component of the broader Mattole and Salmon Creek Forest Health and Wildfire Resilience Project, supported by funding from CalFire. The partners working on this aspect of the project include both the Mattole Restoration Council and the Mattole Salmon Group.

McGinnis Creek is a tributary in the lower Mattole River, featuring extensive low-gradient habitat that covers nearly two miles, and cool summer water temperatures. This makes it promising for the potential of high-quality spawning and rearing habitat for Coho and Chinook salmon, as well as Steelhead.

The McGinnis Creek instream habitat enhancement project will utilize extracted coniferous trees encroaching in upper grassland meadows. These trees will be transported by helicopter and placed in the creek channel with no ground-based movement of materials. The pieces will be strategically wedged among existing riparian trees, large woody debris, and topographic features such as boulders. Currently, the targeted section for wood placement resembles a conventional “bowling alley,” characterized by relatively few shallow pools and a scarcity of large wood and cover. The stream was heavily impacted by timber harvesting and road construction in the 1960s. While recovery has been evident in recent decades (see satellite images below), marked by the growth of a closed alder canopy and channel down-cutting due to decreased coarse sediment loads, the absence of instream large wood and a lack of mature streamside forest hinder the creation of intricate instream habitat. Without substantial wood additions, the prospects for complex instream habitat and reconnecting with the floodplain remain limited. These structures will be placed in a manner intended to complement each other, working in harmony with the stream’s geomorphic processes during material transport.

The design of the wood placement aims to enhance spawning and rearing habitats for Steelhead, Coho, and Chinook salmon by increasing the quantity and complexity of pool cover. This involves promoting gravel sorting and deposition, elevating the streambed in suitable locations to connect floodplain features at lower flows, and encouraging the development and maintenance of side channels and alcoves. Wood features play a crucial role in promoting stream meandering and increasing the heterogeneity of floodplain inundation.

aerial images of Mcginnis Creek 1941-2019