River Tay
The River Tay emerges from Loch Tay at Kenmore, and flows from there to Perth which, in historical times, was its lowest bridging point. Below Perth the river becomes tidal and enters the Firth of Tay. The largest city on the river, Dundee, lies on the north bank of the Firth. On reaching the North Sea, the River Tay has flowed from west to east across central Scotland.
Stockton-on-Tees
Downstream on the River Tees is Portrack Marsh Nature Reserve, a nature reserve by the northern bank of the river between the Tees Barrage and the Tees Viaduct near Portrack housing estate. It is the last remaining wetland on the lower Tees. Ownership of the reserve is split between Tees Valley Wildlife Trust and Northumbrian Water, but the reserve is managed by Tees Valley Wildlife Trust. The west and north part of the reserve is mature marsh while there are a series of man – made ponds in the remainder.