The loss of a safe crossing in 1621 contributed to a decline in the town’s fortunes, and in 1766 Thomas, Earl of Kinnoull headed an effort to obtain funding for a new bridge. Financial backing from the government and the Earl himself, as well as public subscription led to the commission of John Smeaton, architect of the Eddystone Lighthouse, to build a new bridge at Perth. Smeaton’s bridge was completed in 1771and is generally known as Perth Bridge. It was soon put to the test. In February 1774, during a rapid thaw, broken ice became wedged under the bridge, and blocked up the river channel. Most of the town and both Inches were flooded, but the bridge stood firm. Smeaton’s bridge has survived many floods since. Some of the flood levels are marked on the north side of the west most pier. Increasing traffic during the 19th century resulted in the bridge being widened by A. D. Stewart in 1869. The stone parapets were removed, and footpaths projected over iron brackets. Until Tay Street was built and the river bank was raised the River Tay was much wider and there was frequent flooding each winter with the marks on the wall of the dry arch of the bridge noting some of the more recent heights.
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