Chelmer and Blackwater Navigation - Operation

Operation

When completed, the length of the navigation was 13.8 miles (22.2 km). 12 locks lowered the level of the navigation by 75 feet (23 m) from Springfield Basin in Chelmsford to the sea lock at Heybridge Basin. An additional stop lock protected the new cut from flooding at Beeleigh. Here, the navigation left the course of the River Chelmer, and joined that of the River Blackwater, before entering the final 2.5 miles (4.0 km) of cut to Heybridge Basin. The waters of the River Blackwater were diverted into the Chelmer, flowing over a weir between Beeleigh Lock and the stop gates. The navigation was constructed with only 2 feet (0.61 m) of water, which was the lowest statutory draught for any of the English commercial waterways. The locks were constructed to take barges which were 60 by 16 feet (18 by 4.9 m) and each could carry around 25 tons. They were horse-drawn, and remained so until the 1960s, when diesel outboard motors were fitted. The only branch was a cut to Langford Mill, built privately by Mr Westcomb. It was well used until the 1870s, but was unused after 1881.

There were teething problems, with floods in 1797 creating shoals which prevented the passage of barges. These got steadily worse, until Rennie was called back in 1799 to address the problem. Rennie was again recalled in 1805, when the mill owners complained about leakage through the locks and requested damages. Further improvements were made, including the rebuilding of Heybridge sea lock by James Green, and trade developed steadily. The first inland gasworks in Britain was built in Chelmsford in 1819, using coal brought up the navigation. Besides coal, bricks, stone, timber and general cargo was carried from Heybridge to Chelmsford, and the major cargo in the reverse direction was grain and flour. Local wharfs served the communities of Little Baddow, Boreham, Ulting and Heybridge. At its peak in the mid 19th century, the canal was carrying over 60,000 tons of cargo per year.