What lies beneath the surface?

7. oktober 2021

Underneath the surface, our cities hold resources: soil, water, energy, raw materials and space. Unfortunately, the urban subsurface also holds an increasing number of pitfalls, which manifest as flooding, ground movement and contaminated soils. How can we ensure that our cities hold up under population growth, resource demand, increasing commercial activities and more frequent extreme weather events? Knowledge to make good decisions is available. The Urban Geology Expert Group (UGEG) vision is that urban decision-makers have access to tools, data, and knowledge that they need to understand responsibly manage our urban subsurface resources and hazards fully. Under this EuroGeoSurvey expert group, the geological surveys in Europe are united to safeguard our cities.

Digital twin

Living sustainably and in harmony requires a holistic approach to city planning, supported by science-based policy, at every level.

What happens when essential urban subsurface information is overlooked during planning? The services the subsurface provides (our urban geo-ecosystem) are often not maximised or worse ignored completely. For example, unforeseen ground conditions during construction are one of the primary causes of project delays and overspending. Providing relevant and more accessible geological data to the user at the right time and in the right format is crucial to help save money, improve efficiency in planning and development, in resource extraction (water, geothermal, minerals) and to reduce the impacts of geological hazards.

How should this subsurface information be provided? Geoscience data (and, if available, 3D geological models) should be combined with existing information (built structures, both surface and subsurface). For example, Building Information Modelling (BIM) and City Information Modelling (CIM) philosophy will enable users to develop a “Digital twin”, which includes the city below ground. UGEG aims to facilitate collaborations to ensure that geoscience information is fully represented, maintained, and kept up to date to contribute to the planning and construction digital workflows

Nature in cities

A key strategy for attaining sustainable cities is naturalising and re-naturalising the urban surface and subsurface.

Cities have been characterised by their maturity and economic status, resilience and readiness for transformation, but the role of nature, including geology, for city resilience and sustainability is under-appreciated.

For example, water flows in the subsurface and on the surface of our cities – and water does not generally respect boundaries. However, those working with urban water management understand that water flow in urban areas cannot be treated in isolation - the rural-urban connection must be assessed.

A similar approach is needed to understand the impacts of climate, demographic, resource, waste flows and land-use change in the context of the wider geo-environmental setting, which includes the area beyond the city boundary.

This approach would allow decision-makers to assess how:

to support a city’s natural resource needs without causing environmental degradation

multiple pressures, including geo-hazards, effect a city and its services

cities impact on the wider geo-environment, and so determine the long-term interaction of artificial and natural environment with each other

Expert groups

A United Europe to future-proof our cities

The complexity of our cities is increasing. Attaining the goal of sustainable, future-proofed and resilient cities depends on evidence-based decision-making. For example, a city’s subsurface can continue to provide opportunities for retail space, storage, transport tunnels, recreation, energy and natural resources for countless generations to come. However, the subsurface also continues to present hazards to those living and working above and below ground, including flooding, subsidence, toxic soil, radon gas and catastrophic collapse. Geological Surveys are the national, publicly funded agencies that offer knowledge that can help reduce and eliminate hazards and identify subsurface opportunities. These agencies are found in nearly every European country. The subsurface knowledge they produce is readily available online in databanks and user-friendly mapping services aimed at a range of experts, educators, administrators and the general public.

Geological Surveys have long recognised that sharing knowledge and experience can save resources and lives. EuroGeoSurveys (EGS) is comprised of individual members from 38 national Geological Survey organisations. The main objective of all the EGS is “to contribute to improving the operational capacity and economic capabilities of governments, institutions, organisations, businesses, and individuals and define measures and actions.” Urban Geology is one of the many topics that EGS hopes to highlight by establishing the Urban Geology Expert Group (UGEG). Currently, 24 surveys participate in UGEG.

Urban Geology Expert Group (UGEG) members

UGEG supports Europe’s Urban Agenda and urban policies to fulfil the requirements of European Commission Directives and the UN Sustainable Development Goals. Below is a list of geological surveys that have named representatives to the UGEG. In addition, we have randomly selected a few services and publications that have been produced with urban planners and decision-makers in mind.

Geological Surveys participating in UGEG

United Kingdom – Chair of UGEG

British Geological Survey/British Geological Survey (BGS)

Online services for urban decision-makers: