 To allow steamers to bring day trippers to Weston @-@ super @-@ Mare from ports on both the English and Welsh side of the Bristol Channel , a landing jetty was extended on the west side of the island . The Severn Estuary has one of the highest tidal ranges in the world , up to 48 ft ( 15 m ) , second only to the Bay of Fundy in Eastern Canada . The estuary 's funnel shape , its tidal range , and the underlying geology of rock , gravel and sand , produce strong tidal streams and high turbidity , giving the water a notably brown colouration . The tidal range means that the legs of the pier are largely exposed at low tide and hidden at high tide . 
