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Redwood City Stormwater Roadmap <br />Appendix A: Data Review <br />September 2025 A-11 Schaaf & Wheeler <br />Green infrastructure measures are maintained by the owner of the facility but are inspected by <br />City officials once every five years. <br />A.4 Structures <br />A.4.1 Dams <br />A.4.1.1 Existing Studies <br />The City retains detailed records for the Emerald Lake 1 Lower Dam, a privately owned facility <br />located upstream of Redwood City and classified as an “Extremely High Hazard” structure by <br />the California Division of Safety of Dams. Although outside city limits, the dam lies within the <br />Redwood Creek watershed and represents a potential source of downstream flooding. <br />Key documentation includes: <br /> Emerald Lake 1 Dam Break Inundation Study (Schaaf & Wheeler, 2018) <br />This study modeled a sunny-day piping failure scenario using HEC-RAS, estimating a <br />peak breach flow of 5,800 cfs. The analysis detailed downstream attenuation and arrival <br />times within the channel and adjacent developed areas. <br /> Emerald Lake 1 Emergency Action Plan (Spector, 2023) <br />Prepared by the dam’s EAP Coordinator, the Emergency Action Plan defines notification <br />protocols, emergency procedures, and agency responsibilities in compliance with <br />California Water Code and FEMA guidelines. It outlines downstream impact zones and <br />interagency coordination measures for dam-related emergencies. <br />These documents are essential for regional emergency preparedness and should be referenced <br />in future drainage planning and flood response coordination efforts involving Redwood Creek. <br />A.4.2 Bridges <br />A.4.2.1 Inspection Reports <br />Bridge inspection reports are available from the City for six structures. Inspections for bridges <br />35C0074L and 35C0074R (Marine World Lagoon), 35C0033 (Redwood Creek at Veterans <br />Boulevard), 35C0073 (Belmont Slough east of S.H. 101), and 35C0153 (Redwood Creek south <br />of Maple Street) were conducted in 2015. The most recent inspection, for bridge 35C0050 <br />(Cordilleras Creek at Stafford Street), was completed in 2022. <br />A.5 Sea-Level Rise <br />A.5.1 Tidal Data <br />Tidal predictions and data are publicly available through NOAA. Stations Smith Sough, Bay <br />Slough (East End), and Bay Slough (West End) should be utilized for Redwood City tidal data <br />analysis. <br />11.A. - Page 50 of 53 <br />481