24STM1-3L10 Alisal Rd Storm Damage Repairs

On February 8, 2024, a significant storm event, down poured throughout the County of Santa Barbara. Alisal Road and the surrounding area experienced intense rainfall. The storm event caused unusually high runoff volumes due to the high precipitation. The increase in stormwater flow exceeded the capacity of the existing 48" CMP culvert and caused it to clog and led to the excess stormwater to overtop onto Alisal Road. This caused localized flooding and created unsafe driving conditions. The event was designated as emergency event "24STM1" and immediate emergency work was required to restore Alisal Road and the natural alignment of Nojoqui Creek. To prevent or mitigate a future emergency event at Alisal Road, a hydraulic analysis determined that the existing single 48" culvert needs to be replaced with four 48" diameter reinforced concrete pipes to allow the expected stormwater volumes to flow through this area of Nojoqui Creek. Concrete headwalls will be constructed at both the inlet and outlet of the new culvert system, to provide structural support and protect against erosion. These design improvements will be done by open trench excavation, meaning that Alisal Road will be fully closed during construction. Full closure of the road will allow the construction crew to complete the culvert replacements more efficiently and safely, therefore minimizing the construction duration and long-term disruption to traffic. Immediate emergency repair work that was completed previously was statutorily exempt on May 10, 2024, a Notice of Exemption was filed on that basis, and the approved action can be found below: https://santabarbara.legistar.com/LegislationDetail.aspx?ID=6662545&GUID=F7A15D32-BE74-4DD0-AE55-28E07FE744E5.?