Austin Hot Springs Engineering and Permitting

Working with the Confederated Tribes of Warm Springs Reservation Oregon and Wolf Water Resources the CRBC designed a project to restore the natural functions of the site. The Technical Assistance Grant funded engineering, modeling, and permitting work required to undertake restoration actions for this side-channel and riparian restoration project. Water control structures created by unauthorized users will be removed from the hot springs side channel, the heavily compacted parking/camping areas and road will have a new side channel excavated through it. Other areas compacted by long term use will be roughened with slash and trees added to restore organics and provide floodplain roughness. A second channel will be excavated into another impacted area with slash and large wood added. Several large wood structures will be added to the reach to drive water into the new channels and onto existing floodplains. Invasive weeds will be treated the site replanted.

Clackamas River basin focal fish species (i.e. spring and fall Chinook, Coho, winter steelhead and Pacific lamprey) are negatively impacted by loss of habitat, impaired water quality and lack of access to historic spawning
areas. This project will restore habitat elements, including a lack of mainstem and off-channel rearing habitat, that are identified as primary limiting factors for the survival of anadromous salmonids in the Clackamas River. The
project will increase the amount of available side-channel habitat in a reach currently lacking adequate flow refuge and rearing habitat.
The project includes restoration and enhancement of side channel habitat, addition of large wood to the mainstem Clackamas River and decompaction and revegetation of riparian areas degraded by unauthorized use. The design focus will be on improving juvenile rearing conditions for Coho salmon, winter steelhead and spring Chinook salmon. Restoring the side channel and associated riparian area will provide critical habitat for not only juvenile salmonids, but will have significant benefits for a suite of wildlife species that either use or indirectly benefit from such habitats (e.g., amphibians as refuge and reproductive habitat, birds as foraging and nesting habitat, small mammal feeding and resting habitats). During flood events the restored side channel and riparian habitats will offer aquatic species refuge from adverse mainstem conditions created during high flow events. Temperatures are typically moderated in side channels, offering cooler rearing conditions in summer months and during the winter months the hot springs side channels may provide more preferred (slightly warmer) temperatures for rearing. Juvenile Coho are known to actively and preferentially migrate from mainstem rearing locations to off-channel habitats (that would be off mainstem channels) in both fall and spring for protection from winter freshet activity and where they experience high survival rates.
The portions of hot springs side channel and the river through the site provide thermal refugia that overwintering fish may utilize, the warmer water providing more suitable growing habitat during the cold winter months. Improved hydrologic connection is important due to the diversity of fish species and life cycles in the mainstem Clackamas River, increased hydrologic connection should improve on the overall survival rate as opposed to fish rearing exclusively in the mainstem Clackamas River.
The Pacific Northwest is expected to see dramatic increases in temperatures due to climate change, with more rain in winter and spring, increased variability in peak flows, reduced snow-packs and drier summers. The Partners planning documents recommend actions that will recover natural river processes and riparian function through reactivation of the floodplain and natural aggradation of the river. Increasing floodplain inundation provides high velocity refuge for fish, attenuates downstream flooding, increases hyporheic flows and decreases water temperature.