Agmt21 Environmental Science Associates

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Karl Heisler June 18, 2021 Page 2 n\m\c\Redwood City\LP\2021 ESA\Gatekeeper SCOPE OF WORK Our proposed Scope of Work is divided into four key tasks, described in more detail below. • Task 1. Perform Water System Analysis • Task 2. Evaluate Recycled Water Systems • Task 3. Prepare Engineering Report • Task 4. Meeting and Project Management Task 1. Perform Water System Analysis In this task, West Yost will perform a potable water system analysis to determine infrastructure requirements to serve the Project. The following work will be performed: • Update the Hydraulic Model: Update the City’s existing water system hydraulic model to include conceptual pipelines identified in the Preliminary Utility Study and allocate demands provided by the developer’s civil engineer. • Calibrate the Model: Calibrate the model using the field hydrant flow test data provided by the City to verify that the hydraulic model simulates the field test conditions. West Yost will provide a map of all existing fire flow data at existing fire hydrants in the study area. Existing fire hydrant flow test reports will be provided by the City. Locations for the flowing and residual pressure hydrants for each new test will be selected by West Yost and reviewed by the City. Field work for the hydrant tests will be performed by the City. West Yost will perform a minimum of three fire flow test calibrations of the hydraulic model, or up to four hours of model calibration, and will adjust roughness coefficients as needed. To ensure the hydrant flow test field conditions are accurately captured in the hydraulic model for calibration, the City will need to provide current flow rates and pressure information at the SFPUC turnouts that supply the City’s Main Pressure Zone and the time of day that the tests were performed. West Yost will work with the City to estimate the water demand in the Main City area. West Yost will work with the City to estimate zone demand based on seasonal and diurnal information developed for the Water Master Plan, if West Yost cannot satisfactorily determine the Main City Zone demand from the turnout flow rates information. West Yost will review the calibration results to determine if pipeline roughness coefficients that are assigned to pipelines within the Project area in the hydraulic model should be adjusted based on the calibration results. If the pipeline roughness coefficients in the Project area need to be adjusted, West Yost will use the field data to determine the roughness coefficients. Results of the calibration will be presented in the report. The final calibrated hydraulic model shall be submitted to the City as an EPANET file. • Perform Hydraulic Evaluation for Maximum Day Plus Fire Flow Conditions: Conduct a fire flow analysis to determine available fire flows in the Transit District project area under existing demand conditions (existing conditions in the current water system hydraulic model) and for water system buildout conditions with the Project demands. Fire flow requirements will be provided by the Redwood City Fire Department. If available fire flows at buildout of the system are less than the required demand with the Project demand included, West Yost will identify potable water system improvements within the project area to meet fire flow requirements. West Yost shall prepare a map showing pre- and post-project fire flow rates at each hydrant in the project area. REV: 06-23-21 MI ATTY/AGR.2021.150/Environmental Sciences Associates (Gatekeeper Projects) (Page 52 of 58)