Oregon Flood Hazard Data Standard v2.0 Summary of Proposed Amendment

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Oregon Flood Hazard Data Standard v2.0Summary of
Proposed Amendment
Photo Andy Cripe, Corvallis Gazette-Times
Willamette Valley Flood 2012
Collaborative Effort of Jed Roberts (DOGAMI),
Steve Lucker Christine Shirley (DLCD)
GIS Framework Forum 14
November 5, 2014
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What Are We Amending?

• Version 1.0
• Endorsed in December 2006
• Adopted FEMA digital flood insurance rate map
  (DFIRM) database as standard
• DLCD named as steward

GIS Framework Forum 14
November 5, 2014
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Why Are We Amending?

• Flood hazard data is more than FEMA flood
  insurance maps
• Need a standard for other flood mapping, high
  water marks, and flood warning gages
• Additional stewards of flood hazard data

GIS Framework Forum 14
November 5, 2014
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Elements of Amendment

• FEMA Flood Insurance Study Data (Old)
• Probabilistic flood inundation (100-, 500-year,
  etc.)
• For administering the National Flood Insurance
  Program
• Other Flood Study Data (New)
• Probabilistic flood inundation
• Produced by other agencies or local government
• Not necessarily for flood insurance purposes
• Observed Flood Inundation Data (New)
• Flood inundation from actual events
• Created from surveyed high water marks
• Flood Warning Gages (New)
• Not captured in OWRD or USGS stream gage databases

GIS Framework Forum 14
November 5, 2014
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FEMA Flood Insurance Study Data

• Flood Hazard Zones
• 100-year zone most common (where flood insurance
  is required)
• Sometimes 500-year zone is shown
• Cross-Sections
• Locations where flood elevations are calculated
• Flood elevations are interpolated between
  cross-sections
• Study Reach
• Section of river or stream that was studied

GIS Framework Forum 14
November 5, 2014
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FEMA Flood Insurance Study Data
Cross-Section Elevations
Study Reach
100-Year Flood Hazard Zone
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Other Flood Study Data

• Same elements as FEMA Flood Insurance Studies
• Often more scenarios modeled (2-, 5-, 10-year,
  etc.)
• Performed for a variety of reasons
• Need more detailed data than FEMA studies
• Planning
• Restoration
• Mitigation structures (levees, dikes, etc.)
• Dam/reservoir management
• Performed by
• U.S. Army Corps of Engineers
• U.S. Geological Survey
• DOGAMI
• Engineering firms (for cities/counties)

GIS Framework Forum 14
November 5, 2014
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Other Flood Study Data
City of Portland East Lents Floodplain
Restoration Project
GIS Framework Forum 14
November 5, 2014
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Observed Flood Inundation Data

• Flood Inundation Zones
• Extent of actual flooding from specific events
  (as opposed to probabilistic modeling)
• Existing data from 1996 Western Oregon floods,
  Vernonia (2007), Upper Sandy River (2011),
  Mid-Willamette Valley (2012)
• High Water Marks
• Points where flood elevations are surveyed
• High water marks can be used to re-create flood
  inundation zone

GIS Framework Forum 14
November 5, 2014
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Observed Flood Inundation Data
2007 Vernonia flood inundation re-created from
high water marks
GIS Framework Forum 14
November 5, 2014
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Flood Warning Gage Data

• Gages typically not included in
• USGS National Water Information System
• National Weather Service Advanced Hydrologic
  Prediction Service
• OWRD Near Real Time Hydrographics Data
• Gages are managed locally
• Temporary gages
• Staff gages

City of Salem High Water Watch
GIS Framework Forum 14
November 5, 2014
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Activity to Date

• May 5, 2014 Distribution of amended standard to
  Hazard FIT Team for review
• August 5, 2014 Distribution of amended standard
  to larger GIS community (45 day comment period)
• September 19, 2014 Comment period closed
• October 30, 2014 Addressed minor comments
  re-submitted to Framework Coordinator

GIS Framework Forum 14
November 5, 2014