Frazer Creek Rehabilitation Plan

The majority of the Frazer Creek watershed burned during the 2014 Carlton Complex Fire and subsequent flooding resulted in debris flows, excessive sediment deposition, channel migration, channel incision, damage to infrastructure, and loss of aquatic and riparian habitat. The goal for this Rehabilitation Plan was to evaluate the post-fire/flood channel response and recommend suitable rehabilitation actions to address impacts and improve channel and floodplain conditions, water quality, and riparian vegetation.

During multiple post-fire floods Upland sediment yield exceeded transport capacity resulting in deposition, which drove channel migration, followed by incision. Where riparian vegetation was lacking, bank erosion and channel migration were most pronounced. Where the channel was confined (especially adjacent Highway 20), stream energy was concentrated resulting in significant channel incision. Undersized culverts backed-up flow, forcing deposition and channel response immediately upstream.

The rehabilitation plan outlines actions that can be taken to increase and enhance the stream’s natural recovery process. Actions are generally focused around improving floodplain connection and expanding riparian areas, both of which will facilitate natural and long-term bank stabilization, improve water quality, improve habitat, and attenuate future flood impacts. Options are also provided to reduce future head-cut propagation, address existing incision, stabilize channel banks and force high-energy flow away from infrastructure.