query: Is the Firth of Tay a natural waterway?
passage: River Tay
The River Tay (Scottish Gaelic: Tatha) is the longest river in Scotland and the seventh-longest in the United Kingdom. The Tay originates in western Scotland on the slopes of Ben Lui (Scottish Gaelic: Beinn Laoigh), then flows easterly across the Highlands, through Loch Dochart, Loch Iubhair and Loch Tay, then continues east through Strathtay (see Strath), in the centre of Scotland, then southeasterly through Perth, where it becomes tidal, to its mouth at the Firth of Tay, south of Dundee. It is the largest river in the UK by measured discharge.[1] Its catchment is approximately 2,000 square miles (5,200km2), the Tweed's is 1,500 square miles (3,900km2) and the Spey's is 1,097 square miles (2,840km2).
passage: Taymouth Castle
Taymouth Castle is situated to the north-east of the village of Kenmore, Perth and Kinross in the Highlands of Scotland, in an estate which encompasses 450 acres. It lies on the south bank of the River Tay, about a mile from Loch Tay, in the heartland of the Grampian Mountains. Taymouth is bordered on two sides by mountain ranges, by Loch Tay on the third and by the confluence of the rivers Lyon and Tay on the fourth.