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Amendment 1 PSA with Brown and Caldwell for Port Gardner Storage Facility Project <br />Exhibit A Scope of Work <br />23 <br />Work Products <br />• See individual subconsultants work products. <br />Phase 420 – Hydrologic & Hydraulic Modeling <br />Objective: Inform design advancement and operational strategy of PGSF components including new <br />additions such as LS 46 using the existing hydraulic model. <br />Activities/Approach: This task includes the following activities: <br />• Model updates to support task activities. <br />− Incorporate Conveyance Package D when HDR advances it to 30% design. <br />− Refine pipe diameters and alignments of Package ACE to be physically based within model <br />given preliminary understanding. Update at ACE 30% Design. <br />− Refine PGSF major components (basins, pumping, inlet structure, etc.) within the model per <br />refined facility design for both storm and sewer. <br />• Determine stormwater peak flow management strategy and conveyance criteria. <br />− Determine isolation point and automation strategy for peak flow diversion. Model up to 3 <br />scenarios and develop performance assessment of each scenario to inform decision making. <br />− Determine detailed hydraulic criteria for conveyance alignments for preferred scenario. <br />− Develop meeting materials PowerPoint to facilitate decision making within a meeting. <br />− Develop brief TM summarizing modeling analysis and design recommendations. <br />• Support design criteria for LS46 using a regional hydraulic capacity and operations-based <br />modeling approach. <br />− Remove LSX/LS6 from model, replace with LS46 concept. <br />− Model effects of intended LS46 operation on downstream system, determine hydraulic <br />impacts of increased pumping. <br />− Identify acceptable capacity and operational strategy to minimize regional impacts. <br />− Refine operational strategy for LS46 in concert with LS3 for PGSF dewatering. <br />− Develop brief TM summarizing modeling analysis and design recommendations. <br />• Plan for maintenance and failure models of regional system and incorporate into PGSF design. <br />− Define failure mode scenarios at PGSF and of major components and facilities draining to <br />PGSF. <br />− Model scenarios to determine potential impacts to PGSF, required response times, and <br />necessary responses to minimize impacts. <br />− Define maintenance modes at PGSF and of major components and facilities draining to <br />PGSF. Model scenarios to determine flow management strategies by maintenance. <br />− Determine design criteria for PGSF and suggested design criteria for the ACE conveyance <br />package. <br />− Lead meeting to finalize selected maintenance and failure modes. <br />− Lead meeting to review maintenance and failure mode analysis. <br />− Develop TM summarizing modes, analysis, and design criteria.