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EXHIBIT 1 <br /> CITY OF SAN MARCOS <br /> MIDTOWN DRAINAGE IMPROVEMENTS -PRELIMINARY ENGINEERING <br /> SCOPE OF SERVICES <br /> that spills into the watershed area and flows along the Southbound frontage road <br /> of 1-35. Detailed modeling of the Blanco River is not included in this scope. <br /> 3. Hydrologic and hydraulic physical data such as detention pond storage, pond <br /> outlets, and locations of physical structures will be incorporated into the 2D <br /> model. Detention pond storage will be estimated from the LiDAR DEM, project <br /> survey and as-built drawings. Pond outlet structures will be estimated from as- <br /> built drawings,field survey, and site visits. Locations of physical structures such <br /> as residential homes and commercial buildings will be estimated from aerial <br /> imagery and City GIS data. <br /> 4. A 2-dimensional Infoworks ICM hydraulic model will be developed for the entire <br /> watershed.The 2D hydraulic model will be analyzed for the up to five (5)storm <br /> frequencies. Model warnings and errors will be reviewed and addressed as <br /> necessary. Model stability will be evaluated and reduced in order to provide a <br /> quality numeric representation of existing conditions. <br /> 5. The 2D hydraulic model will be analyzed for up to three(3)historical flood <br /> events. Inundation results will be compared against available historic flood data <br /> such as photographs, videos, high water marks, and flood complaints. Model <br /> parameters will be revised as appropriate to best simulate the historic flood <br /> events. <br /> d. Proposed Alternatives <br /> 1. KFA will coordinate with the City to develop criteria for developing conceptual <br /> flood mitigation solutions. KFA will utilize the preliminary hydrology and hydraulic <br /> models to develop three(3) preliminary alternative for flood mitigation for the <br /> project area to include improvements to both the open channel and localized <br /> systems. Improvements will be assessed for both the East and West side of 1-35. <br /> This may include proposed improvements to the ditch capacity, inlet placement, <br /> storm sewer upgrades, culvert upgrades, and pond improvements. <br /> 2. The proposed preliminary alternatives will be simulated to assess the benefit <br /> provided to the observed flooding from the Blanco River along the Southbound <br /> frontage road of 1-35 during the 100-year event only. Specific solutions to the <br /> Blanco River flooding within the watershed for this study will not be developed, <br /> but only simulated to understand how the above mentioned preliminary <br /> alternatives impact the flooding from the Blanco River. <br /> 3. KFA will utilize the hydrologic and hydraulic models to assess and minimize <br /> potential impacts the proposed improvements may have outside of the project <br /> area. These impacts will be discussed with the City, and adjustments to the <br /> selected alternative design will be made to ensure no adverse impacts are <br /> created due to the proposed project. <br /> 4. KFA will develop an Opinion of Probable Construction Cost for each of the <br /> selected alternatives.The cost estimates will include all major construction items <br /> with an overall contingency of 25%as well as long term maintenance cost <br /> associated with each alternative. Unit cost will be based on the City standard bid <br /> items and other regionally applicable data. <br /> 5. After alternative analysis is completed, KFA will meet with the City to discuss the <br /> benefits and preliminary costs associated with the alternatives. The City and KFA <br /> will select a final altemative(s)to move into detailed design. <br /> 6. KFA will create GIS level graphics for the preliminary design to be included in the <br /> Preliminary Engineering Report. <br /> 3 <br /> Page 13 of 20 <br />