Current and future vulnerability of Argyle International Airport to combined river & coastal flooding

Abstract

Argyle International Airport is at risk from coastal and fluvial flooding, especially when coarse sediments are deposited in the northernmost tunnel mouths (through which the River Yambou flows) and constrict the carrying capacity. Building on previous research which employed a “bathtub” approach to show areas of St. Vincent at risk from flooding, we use rainfall-runoff, inundation and storm impact models to formulate storm conditions based on Hurricane Ivan, with sea levels representative of the present-day, 2100 (+ 1.10 m) and 2500 (+ 5.48 m) under the Relative Concentration Pathway 8.5 scenario. Combining these with constricted tunnel flow regimes of 20-100% (representing 1-5 tunnels becoming blocked), we assess the risk of flooding to the runway and the rear access road.

We find that the Airport’s drainage system adjacent to the runway copes reasonably well with the applied flood conditions. In presentday and 2100 sea-level scenarios with flow constrictions of≥80%, only the northern Runway End Safety Area (RESA) is flooded. However this flooding may be sufficient to render the RESA incompliant with International Civil Aviation Organisation regulations by reducing its effective width. The greater and more immediate risk is likely to be to the access road which runs around the eastern side of the runway, which is shown to be vulnerable under Hurricane Ivan conditions (a water level of 4.40 m above mean sea level, consisting of astronomical tide, storm surge and wave setup) with no sea-level rise superimposed.

These results must be interpreted with caution as there is no subdaily precipitation data nor River Yambou flow data, both of which would be required for a more rigorous assessment of the flood risk to the airport. The simplistic representation of the tunnels is also likely to introduce uncertainty by applying an approximate flow solution once the tunnels are full. The main outcome from this work is a modelling framework which could be applied in the future, should better observational data become available to increase the accuracy and robustness of subsequent flood risk assessments.

More information

Identifiers

Catalogue record

Export record