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Docusign Envelope ID:21C696F2-FD37-4E21-94A2-C2BE6A22794A <br /> Task Order 12: Phase 3 Hydrology and Hydraulic Modeling <br /> 1. Update hydraulics and models to reflect the most recent design. <br /> 2. Create InfoWorks ICM model to replicate the existing detention pond and storm drain <br /> system for the Sunset Acres subdivision. Existing conditions model runs will be made for 25- <br /> year and 100-year flows events. <br /> 3. Extend the Sunset Acres InfoWorks model down to the outfall at the San Marcos River.The <br /> model extension will be applied to both existing and proposed design conditions. <br /> 4. Create InfoWorks ICM model for the proposed detention pond and storm drain system, <br /> utilizing the proposed improvements. <br /> 5. Update the InfoWorks ICM model to model inlet efficiency at capturing runoff from Phase 3 <br /> of Sunset Acres in combination with the surface runoff conditions (using 2D hydraulics). <br /> 6. Evaluate the Phase 3 storm drain design and provide recommended design changes to meet <br /> City drainage and storm drain design criteria. <br /> Deliverables: <br /> 1. Updated Phase 3 results and drainage calculations, to be included in drainage plan sheets. <br /> Task Order 13: Phase 3 Environmental Support Services <br /> 1. Assist City in obtaining assessments for the Project as described below: <br /> a. USDOT Environmental Coordination as a result of Federal Highway Administration <br /> (FHWA)funding for the project.This consists of the development of National <br /> Environmental Policy Act (NEPA) documentation covering anticipated impacts from <br /> the project. <br /> 2. Cultural Resources Investigation <br /> a. Archeological Studies: <br /> i. Plummer shall prepare a desktop Archeological Background Study for review and <br /> comment by FHWA. <br /> 1. The background study will involve review of existing files held by the <br /> Texas Archeological Research Laboratory(TARL) and the Texas Historical <br /> Commission (THC)Archeological Sites Atlas to determine if previously <br /> recorded sites or archeological surveys occur within or near the <br /> proposed project area.The location of previously recorded sites and <br /> surveys will be plotted onto USGS 7.5-minute topographic maps for use <br /> in the compliance coordination process. <br /> 2. Archeologists will also consult the USDA-MRCS soil survey maps for the <br /> project location, relevant aerial photography, historical maps, land use <br /> maps, and the Geologic Atlas of Texas to assess the likelihood for <br /> unrecorded archeological resources and make recommendations <br /> regarding the need for further field surveys. <br /> 3. Another resource that will be used is TxDOT's Potential Archeological <br /> Liability Map (PALM) for Austin District, Hays County, which is a <br /> predictive model used to aid in transportation planning and cultural <br /> resource compliance. <br /> Page 13 of 22 <br /> Documentl <br />