Catherine Creek Rivermile 44 Enhancement

Constructed bend during 2017 high flows.

Digital elevation model of constructed channel and swale complexes.

Upstream constructed channel segment prior to activation.

Overview of constructed swale complex.

Relic oxbow pond within a constructed swale complex.

Constructed channel near the downstream end of the project.

Constructed bend during spring 2017 high flows.

Rio ASE provided construction oversight during the summer of 2016 for a one mile long enhancement project on Catherine Creek. The goals of this project were focused around floodplain reconnection and increased habitat complexity for Chinook Salmon and steelhead, specifically juvenile rearing. Rio's principal engineer had been intimately involved with the design of this phase and other phases of this larger 3.5 mile enhancement project that has been getting constructed since 2013.

Construction during the summer of 2016 included the activation of two new segments of main Catherine Creek side channel, six swale complexes, and two side channels. Catherine Creek historically was relocated against the valley wall to accommodate historical farming activity. This project reconstructed channels in a more natural configuration and incorporated multiple swale complexes that will develop into wetland areas providing off channel rearing for juvenile Chinook Salmon and steelhead. A perennial side channel flows in the historic pre-1937 channel location. Ultimately this project increased Chinook Salmon juvenile over wintering habitat by 1,200% and adult Chinook Salmon holding habitat by 1,600% through the project reach (based on HSI modeling).

During the spring runoff of 2017, Catherine Creek spiked up to an approximately 5-year discharge event at the project site. This activated all six swales, two side channels, and extensive portions of the floodplain. Juvenile Chinook Salmon were found in high densities rearing within the off channel complex habitat. Hopefully these young of the year will rear throughout the summer and winter in this project area prior to smolting next spring.