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DocuSign Envelope ID:Al FOD76C-8E37-4295-AO8C-9A99498B56F7 <br /> 0 111110 <br /> ■■■ haLff <br /> ■00000■ <br /> d. Hot Spot Ranking <br /> Using existing condition flood riskand coordination with the City, Halffwill rankeach inventoried <br /> hot spot to identify fifteen (15) high priority locations for further analysis in Task4a and twenty <br /> (20) priority locations for refinement in Task 4b. <br /> Task 4: Develop Stormwater Solutions <br /> Halff will coordinate with the City Project Managerto confirm analysis and updates to stormwater <br /> solutions. Stormwater mitigation solutions will be limited to new analysis of fifteen (15) identified <br /> stormwater projects and refinement of twenty (20) previously identified stormwater projects. Flood <br /> protection measures may include the following structural and non-structural measures as independent <br /> or combination solutions: <br /> • Structural Alternatives <br /> — Storm drain system improvements <br /> — Channel/ditch improvements <br /> — Detention and retention ponds <br /> • Non-Structural Alternatives: <br /> — Voluntary buy-outs or elevation of buildings most prone to flooding <br /> — Flood warning objectives, including signage, flashers, gauges, notifications, or media <br /> ■ This will not include any locations already identified by the City for placing flood early <br /> warning system stream gages or implementing signs and barricades <br /> — Recommendations of potential studies or evaluations to increase resilience <br /> a. New Flood Mitigation Solutions <br /> Halff will conduct new H&H analysis of the identified stormwater problem areas using available <br /> field data provided by the City or collected during Task 2. To develop local flood mitigation <br /> solutions, Halffwill utilize standard rational method for drainage areas of 100 acres or less and <br /> the SCS method for drainage areas greater than 100 acres to determine flows and manning's <br /> equations todetermine pipe and ditch conveyance. Analyseswill follow the criteria andgoals of <br /> the City's Stormwater Technical Manual, as applicable for the development of conceptual <br /> solutions. Conceptual solutions within the airport area will consider FAA requirements related <br /> to minimizing wildlife attractants.Drainage delineations and computational spreadsheetswill be <br /> provided. Halff will identify advanced modeling techniques if needed and will coordinate with <br /> the City Project Manager prior to investigating solutions.Stormwater mitigation solutions will be <br /> limited to fifteen (15) identified stormwater projects.The new solutions will include a one-page <br /> project summary developed under Task 7a.iii that will include the project description,conceptua I <br /> flood mitigation solution, and probable cost estimate. <br /> b. Refined Flood Mitigation Solutions <br /> Halff will review previous flood mitigation solutions and perform minor updates such that the <br /> projects reflect current conditions. Anticipated refinements include review of projects for the <br /> addition of scope/budget items and cost inflation estimation. Stormwater mitigation solution <br /> refinement will be limited to twenty(20) identified stormwater projects. The refined solutions <br /> will include a one-page project sum ma ry developed under Task 7a.iii that will include the project <br /> 7 1 P <br />