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City of Pleasanton—Villages at the Quarry Project Consistency Checklist 15183 Consistency Checklist 230 The proposed project would drain into two separate sewer sheds: Boulder Street and Lift Station 6 and Busch Road and the East Amador Lift Station. A majority of the proposed project (235 single-family homes and 102 multi- family homes) drain to Boulder Street and Lift Station 6, while 75 parcels drain to Busch Road and the East Amador Lift Station sewer shed. Boulder Street and Downstream Sewers With the proposed project, the design storm PWWF flowing west along Boulder Street, just downstream of the proposed project, is proposed to increase from approximately 31,800 gpd to 124,100 gpd (a 289 percent increase in total flow from existing conditions). Despite the significant increase in flow, the analysis does not predict any capacity issues on Boulder Street or Lift Station 4 during PWWF or PDWF scenarios. The additional sewer flow does ultimately drain to Lift Station 6, which experiences significant backup surcharge during PWWF events. The additional flow from the development causes incrementally more backup at Lift Station 6 and decreases the available freeboard upstream of Lift Station 6 along Arroyo Mucho Trail and Hopyard Road during PWWF events. This in turn increases the risk of an overflow at Lift Station 6. The City has recently performed some maintenance on the pumps at Lift Station 6 to try to improve lift station performance. However, updated testing has not been performed, and the City should limit additional flow loading to Lift Station 6 where possible to minimize further backup surcharge. Busch Road and Downstream Sewers With the proposed project and other expected future developments in the East Pleasanton area, the design storm PWWF going west along Busch Road, just downstream of the proposed project, is projected to increase from 27,900 gpd to 223,300 gpd. The resulting flow can be conveyed by the existing sewer along Busch Road to the Nobhill Siphon during PDWF. However, during PWWF, the additional flow causes several pipes to surcharge on Stoneridge Drive and Kamp Drive. The sewer on Kamp and Stoneridge Drive was identified as a capacity deficiency in the 2024 Sewer Capacity Evaluation Report (triggered by the additional flow from other developments included in the evaluation) and an improvement project was proposed (Capacity Project 4). The proposed project would somewhat increase the surcharge identified as a capacity deficiency. However, the proposed Capacity Project 4 would resolve the capacity deficiency associated with the development when implemented.