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<br />. Stilling Basin - A surface and subaqueous inspection of the stilling basin, floor, walls, <br />and the channel immediately downstream will occur. The current structural condition <br />of the stilling basin and downstream erosion are particular issues which will be <br />addressed. The design hydraulic adequacy of the stilling basin to handle the routed <br />.75 PMF will be evaluated and suggestions will be made for options which will <br />adequately provide energy dissipation should the basin be shown to be undersized. <br /> <br />. Service Spillway Crest and Chute - A surface and subaqueous inspection of the <br />spillway approach apron, crest, plunge basin, and spillway chute will occur. The <br />structural condition of the concrete will be evaluated. Two hydraulic issues will also <br />be investigated; the possibility of a throat choke condition at the spillway crest and <br />the adequacy of the spillway chute wall heights to contain the peak .75 PMF flow rate <br />and splash. Rehabilitation needs and logical options will be identified and evaluated. <br /> <br />. Dam Surface - A complete physical inspection of the above water dam surface and <br />immediately adjacent abutments will be conducted. Particular attention will be <br />directed at the right abutment and dam toe where seepage has been identified in the <br />past. Surface movement and seepage monitoring devices will be examined for <br />adequacy. The need for any ongoing monitoring will be identified. <br /> <br />CONSULTANT will prepare a consolidated preliminary project construction cost estimate <br />subdivided sufficiently for cost allocation to the appropriate entities. <br /> <br />4. Geomorphic Evaluation of Elkhead Creek Channel - A bed/bank erosion evaluation will be <br />conducted for the half mile of channel immediately downstream of the dam emphasizing the <br />first 500 feet downstream of the stilling basin. This will address the following items: <br /> <br />. A description of the current channel morphic condition by photograph and narrative. <br /> <br />. Current status of stream stability. <br /> <br />. Possibilities for future bed/bank erosion and related adverse impacts and options for <br />preventing an unacceptable amount of erosion. <br /> <br />. Several criteria will be suggested as a basis for determining how an unacceptable <br />level of erosion and related adverse impact is defined. <br /> <br />. A summary of the geomorphic findings and recommendations for any appropriate <br />remediation will be described. <br /> <br />5. Upon completion of the investigations and analysis associated with this preliminary engineering <br />study, a verbal report will be presented to interested individuals in Craig. A draft written report <br />(3 copies) will be issued for comment before that meeting, and the final report published <br />subsequent to the meeting (5 copies) in accordance with the separately described schedule. <br />The reports will describe existing conditions, evaluations, options for rehabilitation, construction <br />costs, and other relevant issues associated with deciding on the rehabilitation to be undertaken. <br />