Intro to RAFT Rapid Assessment of Flooding Tool

Transcription

1 Intro to RAFT Rapid Assessment of Flooding Tool Ryan Cahill Hydraulic Engineer USACE-Portland District June 25, 2015 US Army Corps of Engineers

2 Outline Motivation behind RAFT RAFT structure Target user group Development status Demonstration 2

3 When Flood Conditions arrive What resources are available to characterize the flood? How useful are these resources/what is missing? 3

4 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

5 Existing Tools USGS WaterWatch 5

6 Existing Tools 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

7 Existing Tools NOAA River Forecast Center 7

8 Existing Tools NOAA Advanced Hydrologic Prediction Service (AHPS) 8

9 More info would be nice How rare really is this event? What levees are in danger? 9

10 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 Discharge (cfs) % 20% 10% 4% 2% 1% 0.2% Annual Exceedance Probability 10

11 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: 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

12 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

13 RAFT Structure Flowchart RAFT RAFT Database Real-time Inputs RAFT Analysis Outputs 13

14 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

15 What is a HUC? HUC: Hydrologic Unit Code HUC-6 (Basin) HUC-8 (Sub-basin) 15

16 RAFT Gage KML Output 16

17 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

18 RAFT Structure RAFT Database Gage/Levee information Flood frequency curves Impacts Historic Peaks RAFT Database Real-time Inputs RAFT Analysis 18 Outputs

19 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 Discharge (cfs) Superseded,USGS Superseded,FEMA Superseded,USACE PRIMARY,USACE % 20% 10% 4% 2% 1% 0.2% Annual Exceedance Probability 19

20 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

21 RAFT: Levee Analysis How to correlate gage stage to levees? 21

22 RAFT: Levee Analysis Levee Gage 2 22

23 RAFT Levee KML Output 23

24 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

25 RAFT: HUC Analysis 25

26 RAFT HUC Results 26

27 Who can use RAFT? FEMA USGS River Forecast Centers Emergency Managers 27

28 RAFT User Levels Casual View RAFT output maps only Basic Run the RAFT tool Advanced Add/Edit underlying data in RAFT 28

29 RAFT output on the web Oregon Emergency Management web-map Updates daily (more frequently during floods) 29

30 Development Status Oregon version released in late 2014 Preliminary data added for AK, WA, ID by FEMA Full expansion to Washington is ongoing 30

31 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

32 Potential Enhancements Link forecasted stage to bridge overtopping Expand to precipitation as well as streamflow Long-term streamflow volume forecasts 32

33 Demonstration Microsoft Excel/Access combo with VBA Familiar format Easy to modify Any agency can use it (no IT issues) 33

34 Questions? 34

35 RAFT Gage Dashboard 35

36 RAFT Gage Output 36

37 RAFT Gage KML Output 37

38 RAFT Levee Dashboard 38

39 RAFT Levee KML Output 39

40 RAFT HUC Dashboard 40

41 RAFT HUC Dashboard 41

42 RAFT Gage Information 42

43 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