2. Severn barrage: site investigation and barrage layout

A marine site investigation was undertaken consisting of a geophysical survey of an area 16km × 5km, 23 boreholes carried out from a barge and probes in intertidal mud areas carried out from a small hovercraft. The investigation broadly confirmed the anticipated sequence of Jurassic, Triassic and Carboniferous Limestone bedrocks and their suitability to support the barrage. Four alternative barrage alignments were considered. An alignment was selected and developed into a detailed layout incorporating 216 turbines, sluices, locks, electrical transmission and a public road.

• INTRODUCTION

• GEOPHYSICAL SURVEY

• GEOTECHNICAL SURVEY

• SUMMARY OF GEOLOGY

• SITE INVESTIGATION RESULTS AND INTERPRETATION

• BARRAGE ALIGNMENT

• BARRAGE LAYOUT

• ACKNOWLEDGEMENTS