10 research outputs found
A flood damage allowance framework for coastal protection with deep uncertainty in sea-level rise
Future projections of Antarctic ice sheet (AIS) mass loss remain
characterized by deep uncertainty (i.e., behavior is not well understood or
widely agreed upon by experts). This complicates decisions on long-lived
projects involving the height of coastal flood protection strategies that seek
to reduce damages from rising sea levels. If a prescribed margin of safety does
not properly account for sea-level rise and its uncertainties, the
effectiveness of flood protection will decrease over time, potentially putting
lives and property at greater risk. We develop a flood damage allowance
framework for calculating the height of a flood protection strategy needed to
ensure that a given level of financial risk is maintained (i.e., the average
flood damage in a given year). The damage allowance framework considers
decision-maker preferences such as planning horizons, preferred protection
strategies (storm surge barrier, levee, elevation, and coastal retreat), and
subjective views of AIS stability. We use Manhattan (New York City)\textemdash
with the distribution of buildings, populations, and infrastructure fixed in
time\textemdash as an example to show how our framework could be used to
calculate a range of damage allowances based on multiple plausible AIS
outcomes. Assumptions regarding future AIS stability more strongly influence
damage allowances under high greenhouse gas emissions (Representative
Concentration Pathway [RCP] 8.5) compared to those that assume strong emissions
reductions (RCP2.6). Design tools that specify financial risk targets, such as
the average flood damage in a given year, allow for the calculation of avoided
flood damages (i.e., benefits) that can be combined with estimates of
construction cost and then integrated into existing financial decision-making
tools, like benefit-cost or cost-effectiveness analyses