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Call to Action Progress and Issues. Lewis E (Ed) Link, PhD Department of Civil and Environmental Engineering University of Maryland. Early Flood Risk Management. Historical Approach. Living with Floods. Current Practice. Flood Control. Deterministic Extrapolation. Flood Risk Management.
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Call to ActionProgress and Issues Lewis E (Ed) Link, PhD Department of Civil and Environmental Engineering University of Maryland
Historical Approach Living with Floods Current Practice Flood Control Deterministic Extrapolation Flood Risk Management Emerging Approaches Risk-Informed Extrapolation Risk Reduction (+ community resilience) Long Term goals
Corps of Engineers Water Resources Infrastructure: Deterioration, Investment or DivestmentNRC, 2012 • “Funding streams in the U S federal budget over the past 20 years consistently have been inadequate to maintain all of the infrastructure at acceptable levels of performance and efficiency.” • “WRDA was developed when new water project construction was at a high point, it was not designed to deal with OMR issues and priorities.”
Hurricane Hazard 500-year peak surge 100-year peak surge
Missouri River Basin - Annual Runoff above Sioux City, Iowa 1 Maf = 1233 Mm3 .2% .2%/97 1% 1881 Flood = Design Criteria 1%/97
The Project Design Flood consists of 3 historical rainfall events • One of the main premises for the PDF rainfall events was that the combination of events had to be considered plausible from a meteorological viewpoint and that they had to have a reasonable probability of occurrence. • The three rainfall events determined for the PDF consisted of the: • 6-24 January 1937 storm (top left) over all areas with the rainfall excess increased by ten percent • Followed four days later by the 3-16 January 1950 storm (top right) • Three days later by the 14-18 February 1938 storm (bottom) transposed 90 miles northward and rotated 20º.
Total PDF Precipitation Observed Apr 19-May 4 2011 Precipitation • Comparison between the Project Design Flood (PDF) Precipitation events and the observed 2011 precipitation event.: • The PDF occurred in 3 events. • The axis of maximum precipitation for the PDF was along and south of the Ohio River. • Maximum rainfall totals for PDF were 24-32” over KY and along the Ohio River • The 2011 precipitation event occurred during 2 events 4/19-4/28 and 5/1-5/4. • The axis of maximum precipitation for the 2011 event was along and just north of the Ohio River in unregulated areas. • Maximum rainfall totals for 2011 event were 12-24” along and just north of the Ohio River. • It should be noted that stages at Cairo were elevated (+10ft or 127% of normal) at the onset of the 2011 rainfall event due to heavy rains in late Feb/early Mar that produced a crest of 53.41’ on 3/18.
Floodways and Backwater Areas 2011 Flood (of Record) Hazard 69% PDF Rainfall ~ 500,000 cfs snowmelt = 80% of PDF discharge System 55% Spillway capacity 20 % Backwater storage !00% channel Improvements Consequences Repair of structures Restoration of floodways Probabilities?????
1900 1960 2010
RISK • Acceptable Risk Policy • (Consider three views): • Personal Risk (equity) • Societal Risk (efficiency) • Cost Benefit Analysis • Group Risk • Policy factors
Infrastructure ResilienceFatalities - Orleans Parish (Model)
Value of Infrastructure Resilience, HSDRRS 20 % 25 % Sample Data, USACE
Philosophy In times of change, learners inherit the Earth, while the learned find themselves beautifully equipped to deal with a world that no longer exists. Eric Hoffer • “You’re going to have to wait (on probabilistic approaches) until the current generation dies off.” • Prof. Ron Hirschfeld, MIT, 1972