Urban Geology in Wales: 3 (UGW3) is the fifth compendium of case histories that the NMW has published in the past 10 years. The aim is to promote applied geology and draw public attention to issues that affect many lives, such as the increasing need for geochemical investigations, renovation of land occupied by industrial sites and aspects of hydro-geological work. Case histories include solutions to problems resulting from mining sites in North Wales and arsenic in South Wales. Topics for geophysical investigations are current, such as using standard tools in major construction projects.
The volume contains 24 diverse papers reflecting the ‘continuing array of challenges that engineering geologist face on a daily basis—not only in Wales but throughout the world’. A non-specialist would find it difficult to read, except for reference to a particular case study. The papers are organized under three sections (1–3): urban areas and construction; geohazards and geoenvironmental issues; and general projects. UGW3 is fully illustrated with relevant photographs, maps, tables, etc., all reproduced in black and white. Most figures and tables are clear, but not all; for example, figure 148 needed to be larger and in colour to clarify the Lower and Middle Coal Measures stratigraphic sequence—the tonal changes are inadequate to clearly differentiate between sequences.
In Section 1, Venus et al. considered the uses and limitations of thematic mapping in the Lampeter district of a set of six applied thematic geological maps commissioned in 2000 by the Welsh Assembly. This was part of a grant-aided project, ‘Applied Geological Mapping in central Wales’, covering three British Geological Survey 1:50 000 scale sheet areas—Builth Wells, Lampeter and Llangranog. Venus et al. concluded that, despite various omissions and lack of relevant data, the series may be used together as a tool for making evidence-based planning decisions. Other papers in this section cover geotechnical challenges, for example, aspects of the A55 Conwy Crossing drift geology (Arber), soft ground conditions on a new bridge design at A5 Pont Melin Rûg, Corwen (Solera & Milne) and the treatment of unstable rock cuttings on the Cambrian Coast Railway (White & Carter).
Geohazards and geoenvironment themes (Section 2) that are covered range from landslide geohazard assessment and remedial measures to rockfall protection on a highway network, slope stabilisation using willow trees, geochemical legacies of mining in the Conwy Valley, volcanic deposits of Snowdonia and Montserrat, and management of arsenic contamination. So-called general projects (Section 3) range from ‘Stratigraphical relationships of Ordovician bentonites’ to the ‘Fforest Fawr Geopark’, and issues from geo-exploitation to geo-tourism. Typically, case studies cover such aspects as site description, geology and history of the area, followed by ground investigations, inspections and the scope of remediation.
Thematic maps by mineral, flood and land-use planners has clearly demonstrated the need for more thematic data, particularly as much rural development in Wales takes place near and along valley bottoms where flooding and landsliding present significant risks. Mining in the 19th century has left many unstable mine entrances, underground workings and deposits of mine waste which can lead to pollution of groundwater. Sustainable long term management of resources and geohazard in rural areas can be achieved only by using the best available geosciences information.
UGW3 covers problems throughout Wales (and elsewhere) and highlights the need for greater guidance focussed on the needs of the engineering sector, addressing potential geomorphological hazards to infrastructure network and how they can be bet avoided or negated. Greater understanding of the dynamic nature of unconstrained river systems in Wales is required and, in particular, their potential to migrate across floodplains. The ongoing problem of contaminated land and pollution of groundwater from past primary and secondary industries is being and will continue to be relevant for the future. Extreme events and climate change continue to cause concern for flood risk.