WOOD RODGERS, INC. (#2026291) - Laserfiche WebLink

City of Pleasanton | Stormwater System Management Plan | PWD 25.601 | PAGE 13 Based on Wood Rodgers’ inspection experience, there is approximately one deficient drainage structure for every 1,500 to 2,000 feet of pipes. This interval translates to an estimated 180 deficient structures with diameters equal to 24‐inch and greater that are likely present in the City’s 70 miles of pipes. Wood Rodgers proposes to survey and inspect up to 90 targeted sites to identify critical condition issues. Upon reviewing the findings from the first phase of inspections, and if warranted by the conditions observed, Wood Rodgers may propose an additional 90 inspection sites. Upon reviewing the collected data in Task 2.3, we will refine our inspection plan and recommend additional sites if necessary. Wood Rodgers will provide traffic control services for up to two days, if necessary. Deliverable(s): Storm drain inspection plan | Inspection photos and notes + survey and inspection reports for 180 sites | Updated geodatabase Task 3 | Hydraulic Model Development/Capacity Evaluation To ensure an accurate hydrologic runoff simulation, Wood Rodgers will import and integrate existing HEC‐HMS models ‐ previously calibrated by both the Alameda County Flood Control & Water Conservation District (ACFCD) and Zone 7 ‐ into the InfoWorks Integrated Catchment Modeling (ICM) model developed for this project. To enhance the model’s versatility for both maintenance assessment and flood control planning, the ICM model will be further calibrated using both small and large historical storm events. In order to accurately assess flood risk and optimize improvement strategies, detailed drainage infrastructure and street network data within the City’s boundaries will be incorporated into the ICM. To precisely identify flooding locations and support future grant applications, Wood Rodgers proposes modeling all critical drainage facilities (including pipes, open channels, pump stations, and street networks) using integrated one‐ and two‐dimensional software. To evaluate facility capacity accurately, the model will incorporate calibrated hydrologic parameters, groundwater inflows, and small catchment runoff. To assess climate change impacts, simulations will include the effects of groundwater emergence and extreme precipitation on the City’s drainage infrastructure. (See Exhibit 10) This analysis will provide quantifiable and defensible flood risk information, laying the foundation for optimized improvements. Task 3.1 – Catchments and Hydrologic Parameters Catchment boundary accuracy is crucial for hydrologic modeling and runoff simulation, especially in determining facility sizing. Overly conservative parameters derived from ‘textbook’ standards could lead to exaggerated design flows and, consequently, cost‐prohibitive capital projects. Wood Rodgers has developed a precise catchment delineation tool that is utilized by other public agencies such as Marin County, Alameda County Flood Control District, and Santa Clara County Valley Water. This tool automates boundary delineation and hydrologic parameter interpretation processes, providing efficiency, consistency, and accuracy. Exhibit 10 EXHIBIT A Docusign Envelope ID: DF86282A-2A84-404C-9F8A-A035AEFBCFF8