... and the design and construction of the bridge foundations in an alluvial flood plain where the rock formation lies several km below the river bed. The scale of that undertaking, both with regard to river training and to foundations, is without precedent and makes the achievement of particular engineering...

...ROM WILLIAMS; T P HOUGHTON © Thomas Telford and ICE 1996 OWEN WILLIAMS MOTORWAYS DESIGN M4 ROADS HIGHWAYS VIADUCTS COSTS RIVERS FLOOD PLAINS RAFTS ROCKS CUTTINGS PLANNING ALIGNMENT A48 WIDENING IMPROVEMENT CROSSINGS BRIDGES PILED SOUTH WALES WEST GLAMORGAN...