Pound lock Lock (water navigation)

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a pound lock on keitele-päijänne canal @ Äänekoski in central finland


a pound lock type of lock used exclusively nowadays on canals , rivers. pound lock has chamber gates @ both ends control level of water in pound. in contrast, earlier design single gate known flash lock.


pound locks first used in medieval china during song dynasty (960–1279 ad), having been pioneered song politician , naval engineer qiao weiyue in 984. replaced earlier double slipways had caused trouble , mentioned chinese polymath shen kuo (1031–1095) in book dream pool essays (published in 1088), , described in chinese historical text song shi (compiled in 1345):



the distance between 2 locks rather more 50 paces, , whole space covered great roof shed. gates hanging gates ; when closed water accumulated tide until required level reached, , when time came allowed flow out.



the water level differ 4 feet (1.2 m) or 5 feet (1.5 m) @ each lock , in grand canal level raised in way 138 feet (42 m).


in medieval europe sort of pound lock built in 1373 @ vreeswijk, netherlands. pound lock serviced many ships @ once in large basin. yet first true pound lock built in 1396 @ damme near bruges, belgium. famous civil engineer of pound locks in europe italian bertola da novate (c. 1410–1475), constructed 18 of them on naviglio di bereguardo (part of milan canal system sponsored francesco sforza) between years 1452 , 1458.








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