The Witham Navigation was soon needing repairs, and the commissioners asked John Rennie for advice in 1802. His report, published in 1803, included recommendations to demolish High Bridge so that a waterway wide could be built under a new bridge, and improvements to the Foss Dyke costing £12,260. Neither action was followed. The canal was difficult to maintain, because much of it ran through sand and quicksand. The situation was more complex, because it had been leased to the Ellisons for three generations, and Richard Ellison III was not keen to spend any money on it. Income from tolls would have more than covered repairs, but there was little that could be done. A challenge to the legality of his lease was considered in the 1820s, but was not thought likely to succeed. He died in 1827, and Humphrey Sibthorp, his niece's husband, who was a proprietor on the River Witham, took over responsibility for it. He asked Isambard Brunel to survey it, and although he did so in 1833, no improvements were made.