  Homeowners around the world elevate houses to manage flood risks. Deciding
how high to elevate a house poses a nontrivial decision problem. The U.S.
Federal Emergency Management Agency (FEMA) recommends elevating existing houses
to the Base Flood Elevation (the elevation of the 100-yr flood) plus a
freeboard. This recommendation neglects many uncertainties. Here we analyze a
case-study of riverine flood risk management using a multi-objective robust
decision-making framework in the face of deep uncertainties. While the
quantitative results are location-specific, the approach and overall insights
are generalizable. We find strong interactions between the economic,
engineering, and Earth science uncertainties, illustrating the need for
expanding on previous integrated analyses to further understand the nature and
strength of these connections. Considering deep uncertainties surrounding flood
hazards, the discount rate, the house lifetime, and the fragility can increase
the economically optimal house elevation to values well above FEMA
recommendation.
