All off-channel surface mining operations shall be provided with a minimum one-hundred (100) year flood protection. Off-channel excavations shall be designed to minimize the potential for levee breaching and/or pit capture. In addition, excavations shall be designed to prevent overtopping of channel banks or levees along Cache Creek and all tributaries and drainage channels (including, but not limited to, Willow Slough and Lamb Valley Slough).
The flood protection upgrades shall be designed and constructed to provide the necessary one hundred (100) year protection without creating a net increase of in upstream or downstream flooding elevations. Upstream flooding could be increased if additional levee construction serves to confine flows to a narrow width, thereby increasing the water surface elevation. Downstream flooding could be increased if floodplain storage areas were removed from the drainage system by constructing levees in areas where they did not exist before (or raising levees that are overtopped in floods up to the one hundred (100) year event). Where feasible, alternative or non-structural flood management designs (potentially using detention basins, infiltration galleries, and/or floodplain storage in noncritical areas) shall be incorporated. New development (such as buildings, levees, or dikes) located within the floodplain shall conform to all applicable requirements of the Yolo County Flood Protection Ordinance and the Federal Emergency Management Agency (FEMA).
(§ 1, Ord. 1190, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)