Johnson Creek Habitat Assessment & Stream Stabilization

JohsonConditionHENDERSON design-build professionals worked closely with Metro in the assessment, design, permitting, and construction management of candidate stream stabilization sites throughout 2.3 stream miles of the Upper Johnson Creek Natural Area within the Clackamas River Basin. For purposes of this effort, Metro defined function-based stabilization as actions taken to protect high ecological function and/or move currently degrading property conditions towards stabilization or an improving trend that meets the conservation objectives for which Metro had purchased the property.

The purpose of the Johnson Creek Habitat Assessment and Stream Stabilization Project was to identify and prioritize a limited number of projects that will begin to mitigate the degraded hydrological and habitat conditions in the upper Johnson Creek watershed. Floods resulting from storm events have caused erosion, bank scouring, and property damage in stream reaches lacking floodplain and riparian vegetation. Johnson Creek is also on the Oregon DEQ’s 303(d) (Water Quality Standards) list as an ‘impaired’ waterbody due to storm water silt and industrial runoff.

 Criteria for restoration or enhancement of the preferred biological and physical habitat for salmonids within the assessment reachJohnsonSurv included: appropriateness for Metro bond funding as stream stabilization projects, stabilization merits of identified project sites, the practical efficiencies of permitting of groupings of stabilization work, and identification of groupings of stabilization work which provide project implementation efficiencies. Additional practical screening criteria included adjacent ownership, access, use, potential liability issues, and fluvial geomorphic advantages or disadvantages.

 Metro prioritized five sites assessed by HENDERSON for functional stream restoration that comprehensively benefit the overall reach of Johnson Creek. HENDERSON produced designs and successfully permitted these projects, re-grouped into three project sub-reaches. HENDERSON prepared bid documents and worked with Metro through project bidding and contractor selection, then provided construction engineering management for implementation of these projects.

 

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