Dispersive-Soil Highway Geohazards in Alberta

January 7, 2026

The Badlands of central Alberta are recognized for iconic geologic formations such as hoodoos and buttes. Several provincial highways crossing the Badlands valley slopes are subject to associated geohazards resulting from dispersive soils, slope instability and erosion. Dispersive-soil related geohazards include excessive erosion in ditches, and void and tunnel formation in natural soils, bedrock and fill, which over time can enlarge to impressive dimensions. Eventually the voids and tunnels may collapse, creating sinkholes and trenches that can be hazardous to the traveling public. The results of site inspections, geotechnical and vegetation assessments, and monitoring and risk mitigation work completed on various dispersive-soil geohazard sites are discussed in this paper. The types of repairs completed to address dispersive-soil geohazards, and lessons learned from the inspection, monitoring, evaluation, and risk management of these challenging geohazard sites are also presented.

Grapel, C., Mackenzie, K. 2025 " Dispersive-Soil Highway Geohazards in Alberta,” in Proceedings of the GeoManitoba 2025 Conference, 21-24 September 2025, Winnipeg, Manitoba: Canadian Geotechnical Society and Canadian Permafrost Association (CGS and CPA)