Estuary and Firth

Catchment Description

The Firth of Forth is the estuary (firth) of several rivers including the River Forth. It meets the North Sea with Fife on the north coast and Lothian on the south. It was known as Bodotria in Roman times. In the Norse sagas, it was known as the Myrkvifiörd.

The Firth of Forth is a sheltered arm of the North Sea and the estuary of the River Forth. From the tidal limit at Stirling to the Isle of May the Forth is long and covers an area of 1,670 km². At Stirling, the waters are shallow and brackish i.e. a mix of sea and freshwater from the river. Great expanses of mudflats exposed at low tide are rich feeding areas for birds. Further down the narrow channel between North and South Queensferry has been bridged first by the Forth Rail Bridge and then later by the road bridges. A deep channel allows large ships to pass under the bridges to the ports of Rosyth and Grangemouth. Further down the Forth widens out and the shores become sandy and rocky interspersed with fishing villages.

Historic influences

The Forth was seen as a major trade route for goods coming from all over the world. This has continued to this very day with many container ships arriving at Grangemouth and Rosyth, the two major ports. Industry has modified the estuary with many area’s being straightened and reinforced to protect important sites for industry.  

Did you know ?

A tunnel existed under the Firth of Forth, dug by coal miners to link the Kinneil colliery on the south side of the Forth with the Valleyfield colliery on the north side. This went to depths of up to more than 2000m and up to more than two miles from its entrance.