Development in floodplains. Development in floodplains must not significantly or cumulatively increase flood hazard or be inconsistent with a comprehensive flood hazard management plan adopted pursuant to RCW 86.12 (provided the plan has been adopted after 1994 and approved by Ecology).
Development in floodplains. Development in floodplains must not significantly or cumulatively increase flood hazard or be inconsistent with a comprehensive flood hazard management plan adopted pursuant to RCW 86.12 (provided the plan has been adopted after 1994 and approved by Ecology). New development or uses, including subdivisions. New development or uses in shoreline jurisdiction, including the subdivision of land, must not be established when it would be reasonably foreseeable that the development or use would require structural flood hazard reduction measures within a floodway during the life of the development or use. Uses and activities within a floodway. The following uses and activities may be authorized where appropriate and/or necessary within a floodway: Actions that protect or restore the ecosystem-wide processes or ecological functions, including development with a primary purpose of protecting or restoring ecological functions and/or ecosystem-wide processes. Bridges, utility lines, outfalls, and other public utility and transportation structures where no other feasible alternative exists or the alternative would result in unreasonable and disproportionate cost. Where such structures are allowed, mitigation shall address impacted functions and processes in the affected section of the watershed. Repair and maintenance of an existing legal use, provided that such actions do not cause significant ecological impacts or increase flood hazards to other uses. Modifications or additions to an existing nonagricultural legal use, provided that the new development includes appropriate protection of ecological functions. Development where structures exist that prevent active channel movement and flooding. Measures to reduce shoreline erosion, provided that it is demonstrated that the erosion rate exceeds that which would normally occur in a natural condition, that the measure does not interfere with fluvial hydrological and geomorphological processes normally acting in natural conditions, and that the measure includes appropriate mitigation of impacts to ecological functions associated with the river or stream. Structural flood hazard reduction measures. New structural flood hazard reduction measures in shoreline jurisdiction may be allowed only when demonstrated by a scientific and engineering analysis that they are necessary to protect existing development and that nonstructural measures are not feasible, that impacts on ecological functions and priority species and habitats ca...
