US Flood risk management in changing times

The traditional regulatory and policy approach to flood risk in the US has been the optimization of benefits and costs, broadly mandated by federal policy. However, optimization may not be the best approach to flood risk management in light of the deep uncertainties we now face. A more incremental approach using a satisficing strategy may be. Flood risk is a function of the hydrologic factors that produce a hazard and the consequences of the hazard interfacing with the people and property exposed. Regretfully, both hydrologists and climatologists seem unable to provide the clairvoyant guidance needed by the water community facing major decisions on flood risk management in the coming years. As the seminal ‘Red Book’ noted, two things have become second nature to policy analysts and risk managers: absolute safety is unachievable, and it is necessary to distinguish between science and policy. The forcing elements and largest unknowns in determining risk rest with understanding the hydrologic factors involved in shaping the hazard.