Intro to RAFT Rapid Assessment of Flooding Tool Ryan Cahill Hydraulic Engineer USACE-Portland District June 25, 2015 US Army Corps of Engineers
Outline Motivation behind RAFT RAFT structure Target user group Development status Demonstration 2
When Flood Conditions arrive What resources are available to characterize the flood? How useful are these resources/what is missing? 3
waterwatch.usgs.gov Existing Tools Shows recent peak flows as percentile of historic flows for the same day Advantages Quick overview of current conditions Drawbacks USGS WaterWatch Percentile of current day 4
Existing Tools USGS WaterWatch 5
Existing Tools http://www.nwrfc.noaa.gov/rfc/ Shows 10-day river forecast Advantages Flood demarcations for context Some Impacts Drawbacks NOAA River Forecast Center Only a subset of gage locations No what-if functionality Limited sense of damage caused 6
Existing Tools NOAA River Forecast Center 7
Existing Tools NOAA Advanced Hydrologic Prediction Service (AHPS) 8
More info would be nice How rare really is this event? What levees are in danger? 9
Flood Frequency Curves Show how rare an event is Return Period vs. Annual Exceedance Probability Flood Frequency Curve Return Period 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr 500 yr 100000 Discharge (cfs) 10000 1000 50% 20% 10% 4% 2% 1% 0.2% Annual Exceedance Probability 10
Colorado 2013 Flood Headlines Discover Magazine: Colorado Deluge could be classified as a 1000-year event Time: The science behind Colorado s Thousand Year Flood University of Copenhagen: 25-50 year flood CU: 100-year flood in many drainages NWS warning: MAJOR FLOODING/FLASH FLOODING EVENT UNDERWAY AT THIS TIME WITH BIBLICAL RAINFALL AMOUNTS REPORTED IN MANY AREAS IN/NEAR THE FOOTHILLS 11
Introducing RAFT Rapid Assessment of Flooding Tool Real-time tool Consolidates data from many agencies Output Informative (e.g. flood frequency) Practical (e.g. levee freeboard) Assists in disaster declaration 12
RAFT Structure Flowchart RAFT RAFT Database Real-time Inputs RAFT Analysis Outputs 13
RAFT Structure Geospatial data (shapefile and kml) Outputs Gages color coded by frequency Levees color coded by freeboard HUCs color coded by frequency RAFT Database Real-time Inputs RAFT Analysis 14 Outputs
What is a HUC? HUC: Hydrologic Unit Code HUC-6 (Basin) HUC-8 (Sub-basin) 15
RAFT Gage KML Output 16
Automated retrieval RAFT Structure Flood forecasts from RFC Observed data from USGS (or others) Historic events Real-time Inputs Ability to manually modify data to run what-if scenarios RAFT Database Real-time Inputs RAFT Analysis 17 Outputs
RAFT Structure RAFT Database Gage/Levee information Flood frequency curves Impacts Historic Peaks RAFT Database Real-time Inputs RAFT Analysis 18 Outputs
RAFT: Frequency Curves Which frequency curve is best? Flood Frequency Curves Return Period 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr 500 yr 1000000 Discharge (cfs) Superseded,USGS Superseded,FEMA Superseded,USACE PRIMARY,USACE 100000 50% 20% 10% 4% 2% 1% 0.2% Annual Exceedance Probability 19
1. Gages Event frequency Impacts 2. Levees 3. HUCs Freeboard Event frequency RAFT Structure RAFT Analysis RAFT Database Real-time Inputs RAFT Analysis 20 Outputs
RAFT: Levee Analysis How to correlate gage stage to levees? 21
RAFT: Levee Analysis Levee Gage 2 22
RAFT Levee KML Output 23
RAFT: HUC Analysis How to tie HUCs to gages? Pick one most representative gage Gage not necessarily within HUC boundary Separate gage for observed and forecast 24
RAFT: HUC Analysis 25
RAFT HUC Results 26
Who can use RAFT? FEMA USGS River Forecast Centers Emergency Managers 27
RAFT User Levels Casual View RAFT output maps only Basic Run the RAFT tool Advanced Add/Edit underlying data in RAFT 28
RAFT output on the web Oregon Emergency Management web-map Updates daily (more frequently during floods) 29
Development Status Oregon version released in late 2014 Preliminary data added for AK, WA, ID by FEMA Full expansion to Washington is ongoing 30
Expanding to other states 1. Identify gages and compile information 2. Gather frequency curve data, decide primary 3. Gather levee data 4. Import geospatial data (HUCs, levees) 5. Import tabular data to RAFT Items requiring programming/scripting background 1. Retrieving data from the local RFC or other state agency website 31
Potential Enhancements Link forecasted stage to bridge overtopping Expand to precipitation as well as streamflow Long-term streamflow volume forecasts 32
Demonstration Microsoft Excel/Access combo with VBA Familiar format Easy to modify Any agency can use it (no IT issues) 33
Questions? Email: Ryan.cahill@usace.army.mil 34
RAFT Gage Dashboard 35
RAFT Gage Output 36
RAFT Gage KML Output 37
RAFT Levee Dashboard 38
RAFT Levee KML Output 39
RAFT HUC Dashboard 40
RAFT HUC Dashboard 41
RAFT Gage Information 42
RAFT: Frequency Curves Principles for selecting primary curve Unregulated sites 1. Western OR: USGS (2005) report 2. Eastern OR: OWRD (2006) report 3. FEMA FIS (tidally influenced) 4. OWRD Peak Estimation Program (with caveat) Regulated sites 1. USACE regulated frequency curves 2. FEMA FIS 43