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9 4 <br /> SCOPE OF WORK (continued) <br /> • The City will provide 90%comments including comments on the Parametrix constructability <br /> review. <br /> • The final plans will be prepared that separate the bid items for the bioretention facility from <br /> the bid items for retrofitting the existing swale. <br /> PHASE 02 MADISON STREET AT EVERGREEN WAY FLOOD REDUCTION AND PROTECTION <br /> ANALYSIS AND DESIGN <br /> Task 2 Analysis of Ways to Reduce Flooding Incidents and Protect Impacted Properties <br /> Activities: Revise the hydrologic/hydraulic models used for the Surface Water Comprehensive Plan based <br /> on the following: <br /> • Perform hydrologic modeling using the 2012 version of Ecology's Western Washington <br /> Hydrology Model (WWHM2012). <br /> • Perform hydraulic modeling using USEPA's Storm Water Management Model version 5.12 <br /> (SWMM 5.1). <br /> • Develop hydrographs from WWHM2012 associated with the 25-year flow frequency for Sub- <br /> basins PC1-12, PC1-13 and PC1-14. <br /> • Determine flow factors for the SWMM 5.1 nodes to be applied to the hydrographs for Sub- <br /> basins PC1-12,PC1-13, and PC1-14. <br /> • Telephone and e-mail coordination with Otak regarding modeling assumptions and <br /> approaches used for the Pigeon Creek No. 1 Surface Water Basin Plan. <br /> • Telephone and e-mail coordination with Otak regarding modeling assumptions and <br /> approaches for this project for incorporation,as applicable, into basin plan models. <br /> • Develop SWMM 5.1 alternative models based on the following: <br /> o Project survey data <br /> o Parallel pipe system in lieu of increasing pipe diameters within Madison Street <br /> • o Larger diameter pipes <br /> o Deeper pipes <br /> o Pipe entrance and exit losses <br /> o Updating tailwater elevations as applicable <br /> o Adding gutters between structure on Evergreen Way and Madison Street to convey node <br /> overflows <br /> o Increased flow rates based on estimated precipitation changes associated with climate <br /> change. <br /> o Anecdotal flooding information provided by the City as a model check. <br /> Deliverables: The following deliverables will be prepared: <br /> • Plots,graphs and model output as needed to illustrate the various model results for <br /> coordination with the City. <br /> Assumptions: The following assumptions apply to this task: <br /> • A calibrated WWHM2012 or SWMM 5.1 model will not be required. <br /> • Otak will finalize basin plan models. <br /> City of Everett 556-1344-007(01/09) <br /> Evergreen Way Water Quality Retrofit 5 August 2014 <br /> Scope Amendment 1 1 20 <br />