Use of Locks in River Navigations
When a stretch of river is made navigable a lock is required to bypass an obstruction such as a rapid, dam, or mill weir — because of the change in river level across the obstacle.
In large scale river navigation improvements, weirs and locks are used together. A weir will increase the depth of a shallow stretch, and the required lock will either be built in a gap in the weir, or at the downstream end of an artificial cut which bypasses the weir and perhaps a shallow stretch of river below it. A river improved by these means is often called a Waterway or River Navigation (see example Calder and Hebble Navigation).
The lowest lock on a navigable river separates the tidal and non-tidal stretches. Sometimes a river is made entirely non-tidal by constructing a sea lock directly into the estuary.
In more advanced river navigations, more locks are required.
- Where a longer cut bypasses a circuitous stretch of river, the upstream end of the cut will often be protected by a flood lock.
- The longer the cut, the greater the difference in river level between start and end of the cut, so that a very long cut will need additional locks along its length. At this point, the cut is, in effect, a canal.
Read more about this topic: Lock (water Transport)
Famous quotes containing the words locks and/or river:
“He’s made a harp of her breast-bane,
Whose sound wad melt a heart of stane.
He’s ta’en three locks o’ her yellow hair,
And wi’ them strung his harp sae rare.”
—Unknown. Binnorie; or, The Two Sisters (l. 41–44)
“We approached the Indian Island through the narrow strait called “Cook.” He said, “I ‘xpect we take in some water there, river so high,—never see it so high at this season. Very rough water there, but short; swamp steamboat once. Don’t paddle till I tell you, then you paddle right along.” It was a very short rapid. When we were in the midst of it he shouted “paddle,” and we shot through without taking in a drop.”
—Henry David Thoreau (1817–1862)