Inner Tay Estuary viridis" - a species normally found only in north-eastern North America. Scottish Natural Heritage has commissioned and published habitat survey reports for the Inner Tay Estuary. Public roads run within a few hundred metres of the both north and south shores providing easy access to view the estuary and its wildlife, though car parking is limited in many places: (south shore) Wormit, Balmerino, Newburgh, Elcho Castle; (north bank) Riverside Drive in Dundee by the railway bridge, Invergowrie, Kingoodie, Port Allen, Powgavie, Cairnie Pier; (in Perth) from both banks, the bridges, Moncreiffe Island; (in Bridge of Earn) the bridge. The minor
Tay Rail Bridge Bouch had used the technique for viaducts including the Belah Viaduct (1860)) on the South Durham & Lancashire Union Railway line over Stainmore, but for the Tay Bridge, even with the largest practicable caissons the pier dimensions were constrained by their size. Bouch’s pier design set six columns in a hexagon maximising the pier width but not the number of diagonal braces directly resisting sideways forces. The engineering details on the Tay Bridge were considerably simpler, lighter, and cheaper than on the earlier viaducts. On these the machined base of each column section docked securely into a machined enlarged section