The varied geology beneath Swansea—from the Coal Measures and Pennant Sandstone in the north to the glacial till and estuarine alluvium along the Tawe corridor—makes a single borehole a risky basis for design. We see it often: a site on Kilvey Hill shows competent rock at 2 metres, yet three hundred metres toward the docks the same formation is deeply weathered and water-charged. Electrical resistivity surveying, and specifically Vertical Electrical Sounding (VES), lets us build a continuous profile of these transitions without running a drill rig across every square metre. The method measures how easily the ground passes an injected current; clay, saturated silt, and saline porewater all read quite differently from dry sandstone or intact limestone. For engineers working on piling layouts or footing designs near the waterfront, that contrast is the difference between a straightforward pad and an expensive over-excavation. Our field crews deploy Wenner and Schlumberger arrays calibrated to the urban noise environment typical of a compact city like Swansea, where buried services and tidal fluctuations in the Tawe add complexity that a textbook survey never accounts for.
A well-constrained VES survey in Swansea’s mixed alluvium-and-rock terrain can map a weathered bedrock trough that a grid of boreholes might miss entirely.
