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I �� <br />' �I� <br />r <br />.. <br />� <br />. proviJe a channel that is stable immediately after rnnstruccion and prior to the <br />full development of riparian vegetation; and <br />. improve water qualiry tu increase the likelihood that a self-sustaining run of <br />salmonids could be maintained downst:aam. <br />� Re-establishment of a fish population within the restored reach is not a goal of the <br />proposed project. <br />� <br />4 Work Plan <br />w <br />Introduction <br />The stream restoration plan was developed based upon the following criteria: <br />• Creation of a 10-foot wide primary flow channel to contain the 2-year flood flow <br />of the stream. <br />• Creation of an overtlow channel to safely contain the estimated 100-year flood <br />event. <br />• Development of the maximum practical meander of the primary channel <br />rnnsistent with optimum hydraulic, aesthetic and habitat considerations. <br />. Provision of a minimum 25-foot buffer from the top of bank of the primary flow <br />channel to the developed site and a minimum of 20 feet on the Hardeson Road <br />side (60-foot total corridor width). <br />Soil bicengineering techniques, used in conjunction with plac�ement of natural fiber <br />geotextiles and rock, would be used to create stable streambanks and erosion resistant <br />slopes. Soil bicengineering techniques include installation of live plant matcrials (cuttings <br />or rooted planu) in a configuration that provides immediate bank protection and encourages <br />development of a dense mat of roou to provide long-term stability. 'These roots provide <br />long-term structural stability to slopes or stream banks. <br />'' Soil bioengineering techniques have been used extensively in Europe, but have been <br />'� less commonly applied in the United States until recently. Robbin B. Sotir & Associates <br />(RSA), an internationally recogni:ed specialry soil bioengineering firm, is the design <br />consultant for this project and has provided input to the design presented in this report. <br />"" RSA and JSA are presently preparing a soil bioengineering manual for King County that <br />,, focuses on streambank stabilization. The �nal design details of the soil bioengineering <br />M azpects of this project will be prepared by RSA. <br />, Soil bioengineering differs from revegetation in that the former provides immediate <br />� <br />streambank stability; that is, there is no need to wait several growing seasons to allow for <br />.. <br />