Page "Canal pound" Paragraph 7

The inverse of a summit pound is a sump pound.

In contrast to a summit pound, a sump pound is a point where every boat entering or leaving the pound causes an addition of water.

The longest one is the Fenny Stratford pound on the Grand Union Canal, between Cosgrove Lock, which starts the ascent to the Braunston summit to the north, and Fenny Stratford lock, which starts the ascent to the Bulborne summit to the south.

Every sump pound needs somewhere to discharge the surplus water, and in this case, a large viaduct and aqueduct immediately to the south of Cosgrove Lock carries the canal over the River Great Ouse, which serves that function.