Oregon Flood Hazard Data Standard v2.0 Summary of Proposed Amendment Collaborative Effort of: Jed Roberts (DOGAMI), Steve Lucker & Christine Shirley (DLCD)

Oregon Flood Hazard Data Standard v2.0

Summary of Proposed Amendment

Collaborative Effort of: Jed Roberts (DOGAMI), Steve Lucker & Christine Shirley (DLCD)

GIS Framework Forum ‘14 November 5, 2014

Photo: Andy Cripe, Corvallis Gazette-Times

Willamette Valley Flood 2012

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


• 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

Why Are We Amending?

1. FEMA Flood Insurance Study Data (Old)• Probabilistic flood inundation (100-, 500-year, etc.)• For administering the National Flood Insurance Program

2. Other Flood Study Data (New)• Probabilistic flood inundation• Produced by other agencies or local government• Not necessarily for flood insurance purposes

3. Observed Flood Inundation Data (New)• Flood inundation from actual events• Created from surveyed high water marks

4. Flood Warning Gages (New)• Not captured in OWRD or USGS stream gage databases

Elements of Amendment


FEMA Flood Insurance Study Data

1. Flood Hazard Zones• 100-year zone most common (where flood

insurance is required)• Sometimes 500-year zone is shown

2. Cross-Sections• Locations where flood elevations are calculated• Flood elevations are interpolated between cross-

sections3. Study Reach

• Section of river or stream that was studied


100-Year Flood Hazard Zone

Study Reach

Cross-Section

Elevations

FEMA Flood Insurance Study Data


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)


Other Flood Study Data

City of Portland – East Lents Floodplain Restoration Project


Observed Flood Inundation Data

1. 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)

2. High Water Marks• Points where flood elevations are surveyed• High water marks can be used to re-create flood

inundation zone


Observed Flood Inundation Data

2007 Vernonia flood inundation re-

created from high water marks


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 WatchGIS Framework Forum ‘14 November 5, 2014

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


Oregon Flood Hazard Data Standard v2.0 Summary of Proposed Amendment Collaborative Effort of: Jed Roberts (DOGAMI), Steve Lucker & Christine Shirley (DLCD)

Documents

flood mapping

observed flood inundation

vernonia flood inundation

flood insurance purposes

flood hazard zones

calculated flood elevations

fema flood insurance

fema flood insurance