Calculating the potential for natural cavities in areas underlain by chalk with a GIS-based algorithm

Karst Susceptibility Hazard Map

South Oxfordshire District Council (SODC) faces mounting pressure to develop land for residential, industrial, and commercial purposes. However, the soluble nature of the chalk bedrock that underlies much of the county can develop extensive karstic features under the right circumstances. Associated subsidence events and ground instability can impact public health and safety and present geotechnical and financial constraints to developments.

Collaborating with SODC, we developed an algorithm based on geographic information systems (GIS) that uses the Edmonds 2001 Subsidence Hazard Rating Formula to calculate the potential for natural cavities to be present in areas underlain by chalk. The result is the innovative, visually powerful, interactive Karst Susceptibility Hazard Map.

The tool can be used by SODC to identify ground instability hotspots and generate a karstic hazard rating that can be passed on to developers, prospective purchasers, or asset owners to ensure that early, informed, cost-effective decisions are made on investment and development across the county and improve awareness when developing in areas of higher risk.

This project was shortlisted for the Ground Engineering Awards 2023 Technical Excellence Award.