Poison Meadow- Sierra National Forest: Bass Lake, 8 Meadows Project
Anabranch Solutions Design and Construction
Trout Unlimited Funding and Coordination
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U.S. Forest Service Partner
Poison Meadow
San Joaquin Basin: Sub-watershed North Fork Willow Creek
Aug. 12, 2023
400
42
Project Goals and Objectives
Meadows within the Sierra National Forest provide unique and important habitat to several species of plants and animals and provide ecosystem services such as water and sediment storage, and resiliency to floods and fire. Anthropogenic impacts over the last two centuries have led to gully formations and channel incision which has led to the draining and degradation of these Meadows. Poison meadow is an active grazing site and suffers from cattle trails that have slowly formed multi threaded channels throughout the meadow. A 2m by 2m headcut also persists at the bottom of the meadow, threating to "unzip" the meadow. Our goal was to slow and ultimately stop the channelization of this system via aggradation and restore sheet and laminar flow regimes. We also hoped to increase sedge and other meadow plant species, which have been found to increase sediment and water retention, as well as promote resilience to disturbance.
Structure Construction Elements
Structures implemented consisted of BDAs located below headcuts to provide direct armoring as well as force backwaters that limit scour and upstream migration. Rock was also placed under the headcuts to prevent further scouring. BDA/PALS hybrid structures were implemented within small channels to promote aggradation and act as "food" for the meadow, allowing the materials to break down and produce peat layers over time. These structures used leafy material and heavy logs, stuffing the channel as much as possible. PALS were also constructed perpendicular to flow throughout the meadow, to disperse water and increase sheet flow. Posts were used in structures of high priority and were flow was most concentrated. Structures ranged in size with widths from 0.3 and 4.7 m and crest heights between 0.14 and 1 m. Materials were gathered onsite as part of a Sierra National Forest thinning project by the Mono Tribe. White Fir was the primary species used with some Sugar Pine and burn debris.
Project Photos
Cover Photo