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2175 N California Blvd <br />Suite 315 <br />Walnut Creek, CA 94596 <br />www.woodardcurran.com <br /> T 800.426.4262 <br />T 925.627.4100 <br /> <br /> <br />Via Electronic Mail <br /> <br />September 3, 2025 <br /> <br />Michael Stella <br />City of Pleasanton <br />200 Old Bernal Avenue <br />Pleasanton, CA 94566 <br /> Re: Arroyo Lago Letter Proposal Sewer Impact Study Update <br />Dear Michael, <br />At the request of the City of Pleasanton, Woodard & Curran has prepared the following scope <br />of services for a task order to provide hydraulic modeling support related to evaluating the impact of the proposed Arroyo Lago development within the area known as East Pleasanton on the City’s wastewater collection system. The work will be based on the hydraulic model <br />developed and used for the Sanitary Sewer Master Plan (Master Plan), which is currently under development although the model has been accepted by the City as appropriate for this <br />purpose. <br />The work items included in this task order are described below. <br />Task 1 – Create Model Loading Scenarios <br />Woodard & Curran will create new model scenarios incorporating the proposed development. Proposed loads for the development will be based on information provided by the City and <br />unit loads consistent with what was used in the Master Plan (160 gpd/unit for single family <br />residential, 130 gpd/unit for multi-family residential). <br />Land Use Scenarios will include: <br />A. Future land use (inside City Boundary only, including proposed Kiewit development) <br />B. Future land use plus Arroyo Lago <br />C. Future land use plus Arroyo Lago plus East Lakes <br />D. Future land use plus Arroyo Lago plus East Lakes plus Amazon <br />Task 2 – Evaluate Adequacy of Sewer System and Assess Alignment Alternatives <br />Woodard & Curran will run the model for dry weather and design storm wet weather scenarios <br />and assess the capacity impact of the flows from the development included in the analysis on <br />the existing downstream sewers. Base wastewater flow unit flow factors, diurnal wastewater <br />flow profiles, infiltration/inflow parameters, design storm rainfall, and hydraulic criteria will be <br />based on those used for the Master Plan. <br />Two potential conveyance alternatives will be considered: <br />• Option 1 would convey Arroyo Lago and East Lakes flows through existing sewers along <br />Mohr Avenue, Palmer Drive, Kamp Drive, and Stoneridge Drive; Amazon flows would <br />follow Busch Road to Ironwood Drive to the above network. <br />Docusign Envelope ID: 0302045F-9523-48FC-9A90-361BBDC311F7Docusign Envelope ID: 3D1FEB1B-42D1-48A5-8938-A1A827EFEF43