Coastal Vulnerability Index

Coastal Vulnerability Index (CVI) mapping to evaluate impacts of sea-level rise


 

Project description

The vulnerability of the coast is intimately correlated to its characteristics and the intricate physical processes that would affect its evolution. Geological Survey Ireland is undertaking a new coastal vulnerability mapping initiative. Maps produced in this project will provide an insight into the relative susceptibility of the Irish coast to adverse impacts of sea-level rise through the use of a Coastal Vulnerability Index (CVI). This method, based on physical parameters, was adapted to the local context to explore the relationships between drivers, (e.g.: sea level rise), geological boundary conditions and the coast's responses.

CVI will offer an easy visual representation of sensitive areas, enabling coastal managers to prioritize or concentrate efforts on adaptation. The main areas of vulnerability will be identified by both CVI and the analysis of individual variables, also called coastal indicators: geomorphology, cliff type, coastline orientation, regional coastal slope, tidal range, significant wave height, relative sea-level rise, and long-term shoreline erosion and accretion rates.

 

Outputs

  • The first phase of CVI mapping (2019-2020) will map areas from north Co. Louth to Co. Wexford. This mapping will also include several data layers of the most relevant coastal indicators to allow the user to view both the coastal vulnerability index (CVI) and the data from which the CVI is calculated.
  • The maps and data here presented can be regarded as a base for developing a more complete inventory of variables influencing the coastal vulnerability to future sea-level rise to which other elements can be added as they become available.

 

Pilot case study

The Coastal Vulnerability Index (CVI) has already being tested on a pilot study run from Portrane to Arklow (Caloca-Casado, 2018). Most vulnerable areas from CVI analysis are shown in high (red) to low (blue) vulnerability ranking.

Coastal Vulnerability Index Map on pilot study from Portrane to Arklow 

Video

https://youtu.be/hOq7ND7ygd4

 

 

Potential flooding areas in Dublin projected by 2100

The combination of a highly-vulnerable environment identified by means of the CVI (High), and detailed assessment of future impacts of sea-level rise (from extreme water levels events), will help to identify vulnerable areas to sea-level rise. The highest depths of inundation expected in the Dublin area from the 200-year return period event (AEP 0.5) are 5.76m OD by the end of the century. These projections are developed using the current understanding of the high-end, worst case scenario of 1.98 m of sea-level rise (RCP 8.5) (Caloca-Casado, 2018).

Potential flooding areas in Dublin projected by 2100 map 

'Potential flooding areas in Dublin from a 0.5 Annual exceedance probability (AEP) event and 1.98m sea-level rise, worst case scenario, projected by 2100'.

This potential flooding projection 2100 is part of Silvia Caloca's thesis published in 2018 using available data at the time. It is not intended to be used for planning or uses other than support the study of the coastal vulnerability mapping project.