The first wet dock in Britain was opened in Liverpool in 1715, and the town's population grew from some 6,000 to 80,000 during the 18th century. The need to develop and protect the port led to a chain of lighthouses being built along the north Wirral coast. The commercial expansion of Liverpool, and the increase in stage coach traffic from Chester, also spurred the growth of ferries across the River Mersey. By the end of the 18th century the Wirral side of the Mersey had five ferry houses, at Seacombe, Woodside, the Rock, New Ferry and Eastham. Other communications were also improving. Turnpike roads linking Chester with Eastham, Woodside, and Neston were built after 1787. In 1793, work began on the Ellesmere Canal, connecting the Mersey with Chester and Shropshire through the fluvioglacial landform known as the Backford gap, and the town of Ellesmere Port began to develop. The excavation of the New Cut of the Dee, opened in 1737, to improve access to Chester, diverted the river's course to the Welsh side of the estuary and took trade away from the Wirral coastline. Although plans were made to overcome its gradual silting up, including one in 1857 to cut a ship canal from a point between Thurstaston and Heswall to run along the length of the Wirral to Chester, this and other schemes came to nothing, and the focus of general trade moved irrevocably to the much deeper Mersey. However, from the late 18th century there was coal mining near Neston, in tunnels stretching up to under the Dee, and a quay at Denhall was used for coal exports. The 19th century The first steam ferry service across the Mersey started in 1817, and steam-powered ships soon opened up the Wirral's Mersey coast for industrialisation. The 1820s saw the birth of the area's renowned shipbuilding tradition when William Laird opened his shipyard in Birkenhead, later expanded by his son John Laird. The Lairds were largely responsible for the early growth of Birkenhead, commissioning the architect James Gillespie Graham to lay it out as a new town modelled on Edinburgh. In 1847, Birkenhead's first docks and its municipal park, the first in Britain and the inspiration for New York's Central Park, were opened, and the town expanded rapidly. Bolstered by migration from Ireland, Wales and rural Cheshire, Birkenhead's population of less than one thousand in 1801 rose to over 33,000