A Practical Approach to Understanding Urban Ground Conditions: A Case Study from the City of Varanasi, India

Urbanisation is a key global issue and a majority of the human population will live in cities by 2050. Hence an understanding of urban resilience and managing the combined socio-economic impacts of migration and climate change on our cities are at the forefront of UN 2015 Sustainable Development Goal 11. The evaluation of the urban ground conditions based on the spatial variability of subsurface geological and geotechnical conditions is an initial step to understanding the city’s resilience to the threats of natural hazards. This approach should be given utmost importance in modern sedimentary basins where the subsurface is characterised by heterogeneous alluvium and weak geotechnical conditions. This chapter addresses the importance of an integrated urban geoscientific framework to highlight the challenging ground conditions within the Quaternary Gangetic alluvium in and around Varanasi City, India. A multi-criterion-based integrated urban development vulnerability map has been prepared to inform the ground strength conditions relevant to the potential for collapse and settlement of the foundation and other surficial infrastructure due to artificial loading and/or natural disasters. This map offers an initial database to planners and design engineers prior to the excavation plan not only within the region but potentially in other similar geological environments and hence informs the decision-making process.