 Following a parliamentary survey of the route by Charles McNiven , the bill received Royal Assent on 13 May 1791 and became an Act of Parliament for the construction of the canal , by which " the proprietors were empowered to purchase land for a breadth of 26 yards on level ground , and wider where required for cuttings or embankments . " The Act allowed the company to raise £ 47 @,@ 000 , with shares of £ 100 . The intention was that at Prestolee the route would divide into two branches ( arms ) , with one branch towards Bolton and the other to Bury , but it would not , however , join the River Irwell . The proprietors were entitled to take water from any brooks within 1 @,@ 000 yards ( 910 m ) of the canal , or within 3 miles ( 4 @.@ 8 km ) of the canal summits at Bolton and Bury . 
