National Dam Safety Program Technical Seminar #22 Thursday February 19 th 2015 Emmittsburg, MD When is Flood Inundation Mapping Not Applicable for Forecasting Victor Hom Hydrologic Services Division National Weather Service 1
Objectives Describe types of Flood Inundation Maps (FIM) Categorize the different purposes Define NWS Goals for Real time Flood Forecast Inundation Maps Describe the Process for Near to Real time Flood Forecast Modeling and Mapping Ensuring the Maps convey Dam Scenarios and Uncertainities 2
Flood Inundation Mapping (Various Purposes) Types of Maps A Priori, Near Real Time, Real Time, A posterori NOAA National Weather Service 3
Flood Inundation Mapping (Various Purposes) Types of Maps A Priori A posterori For Various Types of Risks Probability versus Consequence Consequence Current NOAA NWS AHPS FIM Key Reference: ASFPM Foundation Forum Quantifying Flood Risk, Dr. Gregory Baecher Probability 4
Flood Inundation Mapping (Various Purposes) Types of Maps A Priori A posterori For Various Types of Risks Probability versus Consequence Conveying Varying uncertainties. Aleatory versus Epistemic See NTIS#21 NOAA Presentation on Precipitation Frequency and PMP 5
Flood Inundation Mapping (Various Purposes) Types of Maps A Priori A posterori For various Types of Risks Probability versus Consequence Conveying Varying uncertainties. Aleatory versus Epistemic NOAA National Weather Service 6
NOAA NWS Mission Mission NOAA s NWS provides weather, water, and climate data, forecasts and warnings for the protection of life and property and the enhancement of the national economy. Strategic Goals (4 of 6 Relevant to NDSP) Improve Weather Decision Services Improve Water Forecasting Services Enhance climate services and adapt to climate related risks Improve sector relevant information in support of economic productivity 7
NOAA NWS FIM Goals What are the NWS goals? A Priori, Near Near Real time Real time to Real time Predictive to Modeling Real time Predictive Modeling What risks are NWS trying to capture? High Probability, High High Consequence Risk Risk Events Events What are the uncertainties to be conveyed? Epistemic 8
NOAA NWS Hydrologic Forecasting Modeling (Dynamic Variable Inputs) Precipitation Estimates Radar Data Satellite Data River Gage Data Operations Data Hydrologic Modeling Precipitation Forecasts Snow Temperature Forecasts 9
NOAA NWS Hydrologic Forecasting Modeling (Sample Inputs from WPC) SNOW QPF Deterministic Forecast From preferred model blend Forecaster modifies contours Human deterministic + Ensemble Spread = Probabilistic Prob SNOW >1 95th Percentile QPF Probabilistic Forecast Fully automated via post processing NOAA National Weather Service 1 0
NOAA NWS Community Hydrologic Prediction System (CHPS) I/O Observed precipitation Reservoir Releases Diversion Forecast Precipitation Forecast Temperature Observed flow CHPS Model states Soil Moisture States Deterministic/Probabilistic River Forecasts 11
NOAA NWS Community Hydrologic Prediction System Snapshot Forecast Watersheds Mean Areal Precipitation Sac States: Runoff, Upper Zone (TW,FW) Lower Zone (TW, FZS, FZP) Input (Temp, Precip, SWE, and Hydrograph Time Series) 12 12
Real time Flood Inundation Modeling and Mapping Similar Approaches Modeling (Hydrologic, Hydraulics) Mapping (DEM, Structures, Water Surface) Assessments (Impacts) but More Focus on High Probability, High Consequence, Epistemic Events across various spatial and temporal resolutions. 10,000 m 1000 m 100 m 1 m 13
Flood Inundation Modeling with A Priori Dam Conditions Enhanced Modeling Procedures (Upstream) Dam Failure and Non Failure Scenarios Range of Hydrologic Loading Conditions A Priori Courtesy of Jason Sheeley, USACE 14
Flood Inundation Mapping (A Priori and Real time) Enhanced Modeling and Mapping Procedures Map the Maximum Water Surface Elevation Label the Time of Peak Document the Consequence Store Results in Library During dam incident, 1. issue flash flood warnings based on stored results, 2. rerun forecasts based on dam breach flows and current/forecast conditions, 15
Flood Inundation Modeling (Dam and Downstream Conditions) Enhanced Modeling and Mapping (Downstream) 3. Route the Flood flows to other Downstream Locations, 4. Issue Observed and Forecast Flows with Peak Travel Times 5. Map the Water Surface Levels 6. Determine the Downstream Impacts A Priori, Near Real time, Real time 16
FIM Path Forward Integrated Water Resources Science and Services (IWRSS) Flood Inundation Mapping Requirements Design for the mutual sharing, exchanging, and consuming of current, existing, and futuredelivered FIM (Stream Reach, Historical Flood, Event based Maps) products, its associated metadata, and the documentation of the mapping methodologies for the respective products Implementation 17
When is Flood Inundation Mapping Not Applicable for Forecasting Answer: When the inundation maps do not reflect current/forecast conditions and the likely dam scenario The inundation model needs to include Observed river levels and Real time flood forecast With maps dynamically served based on modeled physics, current in situ conditions, anticipated operations and regulations e.g. dam conditions, and higher degree of certainties 18
Key References Risk, Consequence, and Assessments ASFPM Foundation Forum Quantifying Flood Risk, Dr. Gregory Baecher Workshop on Probabilistic Flood Hazard Assessment, NRC Past NDSP Technical Seminar References Precipitation Frequency PMP, Geoff Bonnin (2014) NWS Communications in Dam Emergencies, Victor Hom (2009) NWS Instruction 10 921 Mapping and Modeling Federal Guidelines for Inundation Mapping of Flood Risks Associated with Dam Incidents and Failures, FEMA P 946 19
Thanks NOAA s National Weather Service Contact Info: Victor Hom (victor.hom@noaa.gov) National Flood Inundation Mapping Services Leader Hydrologic Services Division