Context
Following the earlier urban flood risk assessment, the same coastal municipal authority commissioned a longer-range study projecting flood risk under 2050 and 2080 climate scenarios to inform long-term capital planning.
Approach
The existing calibrated hydraulic model is being extended with CMIP6-based downscaled rainfall projections (SSP2-4.5 and SSP5-8.5) and relative sea-level rise scenarios, with results feeding into a capital planning framework the city can use to sequence infrastructure investment over a 30-year horizon.
Status
This engagement is ongoing, with interim 2050 scenario results delivered and the 2080 scenario and final capital planning framework due in the coming project phase.
Methodology
Extension of the existing calibrated EPA SWMM / HEC-RAS 2D model with CMIP6-downscaled rainfall projections under SSP2-4.5 and SSP5-8.5; relative sea-level rise scenario integration for tidal boundary conditions; capital planning framework development linking modeled risk reduction to investment sequencing.
Results & Outcomes
- Interim 2050 scenario results delivered on schedule
- Established a reusable climate-scenario modeling framework for future studies
Challenges
Reconciling global CMIP6 rainfall projections with the resolution needed for urban-scale hydraulic modeling required a statistical downscaling step validated against the existing calibrated baseline model.