Adaptation Analysis#
💡 Which road interventions are worth the investment?#
When a road network is repeatedly exposed to flood events, it is not enough to know how much damage occurs. Decision-makers also need to know whether an intervention is cost-effective. The Adaptation module in RA2CE answers this question by comparing one or more adaptation options against a business-as-usual reference using a Cost-Benefit Analysis (CBA).
What is a Cost-Benefit Analysis?#
A CBA compares the total expected costs of an intervention against the total expected benefits, both expressed in present-day monetary value.
In the context of road network adaptation:
Costs — discounted construction and maintenance expenditures, expressed per metre of road.
Benefits — discounted avoided damages: the reduction in flood damage compared to the reference (no-adaptation) scenario, accumulated over the analysis time horizon.
The key output metric is the Benefit-Cost Ratio (BCR):
BCR > 1 — the intervention pays off: avoided damages exceed its costs.
BCR < 1 — the intervention costs more than it saves.
BCR = 1 — break-even point.
Future costs and benefits are discounted back to present value using a user-supplied discount rate, and the increasing likelihood of events under climate change is captured via an annual climate factor.
How RA2CE Runs an Adaptation Analysis#
The analysis follows four steps:
Build the network and overlay it with a single-event hazard raster (e.g. a flood depth map). The hazard file must not use a return-period prefix (
RP), as that triggers the separate risk-based damages workflow.Configure damages — choose a manual damage curve (
DamageCurveEnum.MAN) that maps flood depth to road damage fraction. This curve is defined independently for each adaptation option, allowing the reduced vulnerability of the adapted surface to be captured directly.Define adaptation options — each option gets its own folder of input files under
input/<option_id>/. The first option (AO0) is always the reference case; subsequent options represent the interventions being evaluated.Inspect results — the output GeoPackage contains one row per road segment with benefit, cost, and BCR columns for every non-reference adaptation option.
👉 Follow the complete step-by-step example in the adaptation tutorial notebook.
Note
The adaptation module currently requires an event-based setup (single hazard map). Risk-based adaptation across multiple return periods is not yet supported.