Rural Floodplain Zones

10-50.90.040 Floodplains

1. Urban Floodplains

All watercourses and associated floodplains not defined as rural floodplains are urban floodplains. Urban floodplains are typically located in urbanized areas and have typically been altered from their natural state by channelization. Urban floodplains may be altered to address conveyance and erosion concerns, provided that all necessary requirements of the City’s Stormwater Regulations as administered by the Stormwater Manager are addressed. However, certain urban floodplains that have characteristics conducive to water quality, wildlife habitat, and stream ecology should be preserved. Proposals for any disturbance of these watercourses shall be reviewed by the Stormwater Manager and must address these attributes and provide for mitigation if necessary. Undergrounding of urban floodplains is strongly discouraged and a justification must be provided prior to any approval of undergrounding.

2. Rural Floodplains

Rural floodplains are natural undisturbed open spaces that are unsuitable for development purposes due to periodic flood inundation and the need to preserve the stream corridor for beneficial uses such as the preservation of important ecological resources. Rural floodplains are delineated in Section 10-90.50.030 (Rural Floodplain Map) and defined as areas of delineated 100-year floodplain that cannot be disturbed or developed except for roadway and utility crossings. Rural floodplains cannot be altered through a floodplain map amendment or revision and must remain undisturbed (i.e. 100 percent protection). The extension of rural floodplains beyond the limits of the delineated floodplains, both upstream and laterally, may be required based on more current or extended floodplain studies, master plan documents or other studies or documents related to hydrology, hydraulics, stream geomorphology, wildlife habitat, or wildlife corridors.