 In 1976 , the BWB decided after a meeting with local councils that the Forth and Clyde canal , fragmented by various developments , was to have its remaining navigability preserved by building new bridges with sufficient headroom for boats and continuing to maintain the existing locks . Restoration of sea @-@ to @-@ sea navigation was deemed too expensive at the time , but there were to be no further restrictions on its use . A 1979 survey report documented 69 obstructions to navigation , and sought the opinions of twenty interested parties to present the Forth and Clyde Local ( Subject ) Plan in 1980 . 
