In 1812 another act was passed, entitled, An Act to explain, amend, and enlarge the Powers of certain Acts passed for making and maintaining the Grand Junction Canal, by which the proprietors were enabled to complete their truly arduous undertaking, and, agreeably to the provisions of the said act, to make a sufficient reservoir for supplying the mills situated on the River Colne; they were also pledged by this act to make similar reservoirs for the mills upon the Berkhampstead or Bulbourne River, and on the united Rivers Bulbourne and Gade; which however they did not do; but, in lieu thereof, erected a steam engine near Nash Mill, on the Bulbourne and Gade, and also made and worked side-ponds at four locks, situate near Nash Mill aforesaid, in order to diminish the consumption of water. Disputes having arisen between the company and the owners of the various mills, through the ponds of which, by some great error, the line of canal passes, and great delays having occurred in passing the above-noticed locks, the company applied for and obtained another act, bearing date 17th March, 1818, entitled, An Act to enable the Grand Junction Canal Company to vary the Line of Part of their Canal in the county of Hertford, and for altering and enlarging the Powers of several Acts relating to the said Canal.
By this act that part of the canal between Frogmoor Swing Bridge, in the parish of Hemel-Hempstead, and its junction with the Tail Water of Nash Mill, was abandoned, and the line of canal carried into the united Rivers Bulbourne and Gade, as far as Nash Mill aforesaid, thereby preventing waste of water and loss of time in navigating. The company are also enabled to borrow a further sum of £30,000 for the purposes of the act; for completing the said deviation; and for making any other improvements on the same.
The next act was obtained in June, 1819, and entitled, An Act to vary and alter certain Acts of his present Majesty, relating to the Grand Junction Canal, the Grand Junction Water Works, and the Regent's Canal, in order to effect an Exchange of Water, for the better Supply of the Regent's Canal Navigation and Grand Junction Water Works.
It will be now necessary to state the different levels on which the canal is constructed, from its junction with the Oxford Canal
