Laserfiche WebLink
", HZTTITAS COUNTY <br />DEPARTMENT OF PUBLIC WORKS <br />K1171TASCOUNII <br />WSE will develop a simple HEC -RAS model of Big Boulder Creek in the vicinity of the bridge <br />crossing using topographic base map. The model will not be calibrated because observed <br />discharge/highwater marks are not available. Instead, WSE will use engineering judgment to <br />select and adjust model parameters. The model will be used to help size the bridge waterway, to <br />provide data required to evaluate lateral erosion and scour potential, and to develop <br />countermeasures. <br />TASK 4.60 — Channel Stability and Scour Assessment <br />WSE will determine if lateral erosion, local scour, ice, or debris flows pose a threat to the <br />proposed crossing. If they do, WSE will work with KPFF to address these hazards in the design. <br />Assumptions: <br />• These hazards will be addressed through modifications the structure itself (e.g. deeper <br />foundations, longer bridge, etc.) and not through design and installation of external <br />countermeasures (e.g. riprap). If countermeasures are required, the optional task at the <br />end of this scope will be completed. <br />TASK 4.70 — WDFW and Permit Coordination <br />It is anticipated that WDFW personnel have an idea of the length of crossing they would like to <br />see at the site. WSE will work with WDFW personnel, the County, and Jacobs (the company <br />that will acquire the project permits) to collectively arrive at a bridge length that is acceptable to <br />all parties. An allowance is provided for WSE's lead engineer to participate in one meeting with <br />WDFW personnel in Ellensburg. <br />Assumptions: <br />• A reasonable bridge length will be agreed to that the County can afford to build. <br />TASK 4.80 — Hydraulic Design Report <br />WSE will prepare a hydraulic design report to summarize and document the results of the <br />investigation. It will include the recommended NBIS Scour Code rating for the new structure, a <br />code that the County will need for their records. <br />Assumptions: <br />• A draft of the report will be provided to the County and KPFF for review. Upon receipt <br />of comments, WSE will refine the report and submit a final version as a PDF. <br />TASK 4.90 — Meetings and Administration <br />