What's that SMELL??!!! The creation of the Underfall...
After the Bay of Fundy in Nova Scotia the Bristol Channel has the second greatest tidal range of any in the world - it can be as much as 14 metres at Avonmouth but even in Bristol itself it can rise and fall as much as 1 metres!
With Bristol becoming a more and more popular port, causing congestion on the river, there were many good reasons for building the Floating Harbour but perhaps the most important was that as the tide went out in the docks, the ships that were moored there would sink to the bottom and get stranded in the mud. As it was so crowded the danger of a fire starting on one ship and spreading to all of the others, with no chance of controlling the spread, was increasingly high. Boats were also in real danger of tipping over and getting damaged. The phrase 'Shipshape and Bristol fashion' was first used to describe a ship that was strong enough to survive entering, docking and leaving Bristol's port.
But what about the negatives for building a Floating Harbour? One of the biggest was the stink!
By closing off the harbour with a series of locks, sewage was trapped inside and built up. Areas of the Floating Harbour began to silt up especially by Prince's Bridge which is next to the Arnolfini, along Welsh Back near to the Old Vic and opposite Canon's Marsh where the M Shed is today. There were even complaints made that there was less space to moor - 'vessels drawing more than 16 feet cannot find a berth'.
Some thought the terrible smell was due to sewage being dumped in the water, others thought it was waste water from ships. The foul smelling vapour was blamed by some for fevers and sickness.
It got so bad that in 1832 Isambard Kingdom Brunel designed sluices, known as the Underfall. He also made a special boat known as a dredger to help take the mud away. It used a blade like a bull-dozer's.