CITY COUNCIL REGULAR AGENDA PACKET

City of Pleasanton | Stormwater System Management Plan | PWD 25.601 | PAGE 12 elevations. The LiDAR‐derived facility rim or ground elevations will be used in conjunction with inspection data to verify the record drawing data. The spatially‐rectified facilities will be used in conjunction with the georeferenced record drawings to realign storm drain alignments and to identify other paved‐over facilities, such as junction boxes and transition structures. The georeferenced record drawings will also be used to record storm drain materials, diameter/dimensions, lengths, and upstream and downstream inverts (both original and converted NAVD 88 datum). The geodatabase will include an inventory of all the storm drains, grade breaks (storm drain invert slope changes), maintenance holes, outfalls, junction boxes, large trash capture devices and transition structures. Deliverable(s): Georeferenced as‐builts for 10 miles of drainage facility | Updated geodatabase Task 2.6 – Survey & Inspection Wood Rodgers will perform site visits, surveys, and inspections to supplement the data gaps identified in the Data Collection task (Task 2.3) and to collect sufficient storm drain condition information for assessment. Wood Rodgers will prioritize, survey, and inspect storm drain facilities at crucial locations along the storm drain systems. This strategic approach minimizes the need for extensive inspection and closed‐circuit television (CCTV) efforts, allowing us to focus on the quality of the survey. The prioritization of sites for inspection will be based on the likelihood of deficiencies, which will be determined through our technical analysis, modeling results, topography, and previous inspection experience. This approach typically incurs only 10‐20% of the total spot or CCTV inspection costs. Wood Rodgers’ strategic prioritization approach (see Exhibit 5) has been developed and refined through our extensive experience with storm drain inspections. This cost‐saving strategy focuses on surveying and inspecting facilities at crucial locations including upstream and downstream ends, major junctions or bends, metal pipes beyond their service life, steep systems at open spaces, systems prone to high backwater sediment, areas with joint separation risks, andlocations with high trash loading. Our experience has found that this approach allows for the accurate collection of overall storm drain system geometry and materials. Additionally, it enables us to predict and inspect up to 80% of existing deficiencies. A system‐wide survey and inspection plan will be developed for City review prior to beginning field work. Wood Rodgers will document the storm drain survey technique, procedures, and equipment used to accurately measure pipe inverts, diameters, and locations. Conventional maintenance hole dipping surveys will not yield accurate pipe diameters or inverts because the eyeballing technique is not accurate when the ground is 10 to 20 feet above the pipes. Wood Rodgers’ technique with modified equipment and LiDAR scanners (see Exhibit 6) has been used successfully with high accuracy for multiple agencies. Maintenance holes, junction boxes, transition structures, and storm drains’ horizontal GPS coordinates (X,Y) will be surveyed; storm drains’ diameters and inverts will be measured; storm drains’ materials and flow directions will be recorded; sediment and debris depths will be estimated and documented with pictures and field notes; and any structural deficiencies such as corroded metal pipes and cracked walls, will be documented with field notes and pictures. Wood Rodgers will also visit major storm drain outfall structures to inspect for any structural integrity, sediment, and erosion problems. Outfall structure flap gate and cathodic protection system conditions will also be assessed and documented. The collected data, pictures, and notes will be stored in the geodatabase. We will provide a survey and inspection report for each site as shown here in Exhibit 7. Exhibit 7 Exhibit 5 Exhibit 6 EXHIBIT A Page 169 of 376