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KITTITAS COUNTY <br />DEPARTMENT OF PUBLIC WORKS <br />PUBLIC WORKS — BOARD OF COUNTY COMMISSIONERS <br />STUDY SESSION STAFF REPORT <br />STUDY SESSION DATE: December 12, 2016 <br />TOPIC: Wilson/Naneum Split <br />ACTION REQUESTED: Provide Staff Direction <br />LEAD STAFF: Mark R. Cook <br />RECOMMENDATION: <br />Support efforts removing accumulated streambed from Wilson Creek <br />BACKGROUND: <br />Recently, staff has been approached by City of Ellensburg staff regarding <br />accumulated streambed gravel in the Wilson leg of the Wilson/Nanuem split flow <br />control structure. Significant debris has accumulated adjusting streambed profile <br />by approximately three feet in elevation. It is unclear as to how irrigation <br />operation has proceeded in the past, but current operations appear to be <br />insufficient allowing natural scour of the Wilson channel. It is assumed that <br />current irrigation practices do not adequately consider impacts to both stream <br />systems. <br />Staff has received title insurance information for both properties associated with <br />the flow control structure splitting Wilson and Naneum Creeks. The easterly <br />property records an easement for access to repair and maintain the dike and <br />structure and for "emergency purposes". <br />DISCUSSION: <br />While we have verified our right of entry and the ability to conduct maintenance <br />and actions supporting "emergency purposes" — our obligation to perform these <br />actions remains unclear. Electronic searches of Public Works records do not <br />inform us of any recorded memorandums of understanding or other agreements <br />stipulating our obligations. Management of the flow control structure remains <br />private — supporting downstream property owner water rights. <br />Dredging of the Wilson Creek streambed is required to avoid significant <br />increases to Naneum Creek flow. Once flow control (boards) is removed from <br />the Naneum Creek structure, the aggraded Wilson channel will likely see minimal <br />flow. Allowing the bulk of combined flows into Naneum Creek is expected to <br />adversely impact downstream residents. Our bridge at Bar 14 Road was <br />adversely impacted last year owing to aggraded streambed conditions in <br />