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Appendix G. Flood Hazard Management Risk Areas

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APPENDIX G. FLOOD HAZARD MANAGEMENT RISK AREAS This appendix contains a complete listing of the flooding and erosion related risk areas identified by the River and Floodplain Management Program staff during the preparation of the 2006 King County Flood Hazard Management Plan. The approach to identifying and characterizing these risk areas varied from river to river and was influenced by both the characteristics of each river, and by the professional judgment of the team compiling this information. This risk identification was the first step in the development of project and program proposals contained in Appendices E and F of this Plan. These project and program recommendation are cross referenced in the last columns of this table. In many cases the magnitude of these risks described is not well understood but will be further evaluated through future technical studies and risk assessments. South Fork Skykomish River, Miller River, Maloney Creek, Tye River and Anthracite Creek (WRIA 7) In DS US Bank Flood or Channel Migration Risk Action Proposed Project RM RM Plan? 6.4 19.9 L, R South Fork Skykomish River Channel Migration Zone Y South Fork Skykomish Channel Migration Zone: Study and Map: Channel migration is a type of flood Conduct South Fork Skykomish River Channel Migration hazard. King County maps channel migration zones to Zone Study and Mapping. (Skykomish River, identify the extent of this flood hazard and regulate land use Unincorporated) in the affected areas. Historical and recent evidence indicates that this part of the South Fork Skykomish River is subject to channel migration. A South Fork Skykomish River channel migration zone study and map will be completed under this project for use by the King County Department of Development and Environmental Services in land use regulation within King County. (Skykomish River, Unincorporated) 7.8 7.8 L Parcel Number 7809400070: This existing home has Y South Fork Skykomish River Early Action Residential repeatedly experienced damage from flood events. Flood Hazard Mitigation: Purchase and remove structure, Repetitive damage to this structure was determined by or otherwise mitigate flood risks to, repetitive loss FEMA based on existence of a flood insurance policy and properties. (South Fork Skykomish River, Unincorporated) claims paid by that policy. Based on the amount and number of claims that have been paid, this property is identified as being at high risk for future flood damage. (South Fork Skykomish River, Unincorporated) Appendix G Page 1 2006 King County Flood Hazard Management Plan January 2007 In DS US Bank Flood or Channel Migration Risk Action Proposed Project RM RM Plan? 7.8 7.8 L Parcel Number 7809400090: This existing home has Y South Fork Skykomish River Early Action Residential repeatedly experienced damage from flood events in King Flood Hazard Mitigation: Purchase and remove structure, County. Repetitive damage to this structure was determined or otherwise mitigate flood risks to, repetitive loss by FEMA based on existence of a flood insurance policy properties... (South Fork Skykomish River, Unincorporated) and claims paid by that policy. Based on the amount and number of claims that have been paid, this property is identified as being at high risk for future flood damage. (South Fork Skykomish River, Unincorporated) 7.8 7.8 L Parcel Number 7809400100: This existing home has Y South Fork Skykomish River Early Action Residential repeatedly experienced damage from flood events in King Flood Hazard Mitigation: Purchase and remove structure, County. Repetitive damage to this structure was determined or otherwise mitigate flood risks to repetitive loss properties. by FEMA based on existence of a flood insurance policy (South Fork Skykomish River, Unincorporated) and claims paid by that policy. Based on the amount and number of claims that have been paid, this property is identified as being at high risk for future flood damage. (South Fork Skykomish River, Unincorporated) 7.9 7.9 L Parcel Number 7809300140: This existing home has Y South Fork Skykomish River Early Action Residential repeatedly experienced damage from flood events in King Flood Hazard Mitigation: Purchase and remove structure, County. Repetitive damage to this structure was determined or otherwise mitigate flood risks to repetitive loss properties. by FEMA based on existence of a flood insurance policy (South Fork Skykomish River, Unincorporated) and claims paid by that policy. Based on the amount and number of claims that have been paid, this property is identified as being at high risk for future flood damage. (South Fork Skykomish River, Unincorporated) 7.9 7.9 L Parcel Number: 7809400160: This existing home has Y South Fork Skykomish River Early Action Residential repeatedly experienced damage from flood events in King Flood Hazard Mitigation: Purchase and remove structure, County. Repetitive damage to this structure was determined or otherwise mitigate flood risks to repetitive loss properties. by FEMA based on existence of a flood insurance policy (South Fork Skykomish River, Unincorporated) and claims paid by that policy. Based on the amount and number of claims that have been paid, this property is identified as being at high risk for future flood damage. (South Fork Skykomish River, Unincorporated) Appendix G Page 2 2006 King County Flood Hazard Management Plan January 2007 In DS US Bank Flood or Channel Migration Risk Action Proposed Project RM RM Plan? 8.9 8.9 R Parcel Number: 7349800250: This existing home has Y South Fork Skykomish River Early Action Residential repeatedly experienced damage from flood events in King Flood Hazard Mitigation: Purchase and remove structure, County. Repetitive damage to this structure was determined or otherwise mitigate flood risks to repetitive loss properties. by FEMA based on existence of a flood insurance policy (South Fork Skykomish River, Unincorporated) and claims paid by that policy. Based on the amount and number of claims that have been paid, this property is identified as being at high risk for future flood damage. (South Fork Skykomish River, Unincorporated) 17.5 17.5 L Parcel Number 2526119037: This existing home has Y South Fork Skykomish River Early Action Residential repeatedly experienced damage from flood events in King Flood Hazard Mitigation: Purchase and remove structure, County. Repetitive damage to this structure was determined or otherwise mitigate flood risks to repetitive loss properties. by FEMA based on existence of a flood insurance policy (South Fork Skykomish River, Unincorporated) and claims paid by that policy. Based on the amount and number of claims that have been paid, this property is identified as being at high risk for future flood damage. (South Fork Skykomish River, Unincorporated) 7.1 7.4 R Montagna Park: The upstream end of NE 196th Street has N Feasibility and technical analysis required. been undermined by severe bank erosion during moderate flooding. Emergency revetment construction did not achieve a slope that will be stable over the long term. Both the road and one residence are at risk from this erosion problem. Several homes and nonresidential structures exist in both the floodplain and floodway; many were built after 1993. (South Fork Skykomish River, Unincorporated) 7.4 7.6 R Chamonix: Bank erosion threatens several homes built N Feasibility and technical analysis required. very near the edge of the river bank. A revetment of large rock riprap has slowed, but has not halted, this erosion. (South Fork Skykomish River, Unincorporated) 7.5 7.9 L Skylandia: Existing homes have been inundated by fast- N Feasibility and technical analysis required. moving flood waters. Erosion and deposition damages are locally severe. Residential damages included structural problems as high-velocity waters shifted homes on their foundations. Flood study shows 100-year depths as great as 8 feet at these homes. (South Fork Skykomish River, Unincorporated) Appendix G Page 3 2006 King County Flood Hazard Management Plan January 2007 In DS US Bank Flood or Channel Migration Risk Action Proposed Project RM RM Plan? 7.8 8.0 R Skyko Park: Several residential erosion problems have N Feasibility and technical analysis required. been patched with revetments and rockeries that are not showing recent damages but remain susceptible to extreme flood flow. Several homes and nonresidential structures exist in both the floodplain and floodway; it appears some were built after 1993. (South Fork Skykomish River, Unincorporated) 8.1 8.9 R Riverwood Park: Several residential erosion problems N Feasibility and technical analysis required. have been patched with revetments and rockeries that are not showing recent damages but remain susceptible to extreme flood flow. Several homes and nonresidential structures exist in both the floodplain and floodway; it appears some were built after 1993. Flood study shows 100-year depths of 3 to 6 feet through most of this large subdivision. (South Fork Skykomish River, Unincorporated) 7.9 8.4 L Baring Left: Severe channel erosion problems have been N Feasibility and technical analysis required. evident in this area, especially near the south end of 639th Ave NE, where one home was nearly undermined and perched over a tall vertical erosion scar that has been patched with concrete revetments. Although such revetments and rockeries are not showing recent damages, they remain susceptible to extreme flood flow. (South Fork Skykomish River, Unincorporated) 10.8 12.2 R Grotto: Extensive fill restricts natural floodplain N Feasibility and technical analysis required. conveyance and storage functions. (South Fork Skykomish River, Unincorporated) Appendix G Page 4 2006 King County Flood Hazard Management Plan January 2007 In DS US Bank Flood or Channel Migration Risk Action Proposed Project RM RM Plan? 12.6 13.2 L, R Money Creek: Logs and debris are jammed against the N Feasibility and technical analysis required. piers of the Miller River Road bridge over the South Fork Skykomish River at the Money Creek Campground. Downstream of the bridge, severe bank erosion has claimed residential property but does not imminently threaten residences.
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