Worked Example 11.2
A thrift lock has four basins of the same length (225 m) as the lock, and
each of width 20 m. If the width of the lock chamber is 12 m, its total lift is
24 m, and the residual head on each thrift basin is 0.20 m, determine the
efficiency of the thrift lock and the daily saving in water consumption if
there are 18 lockings per day.
Solution
From equation (11.26) with K12/200.6,
x 7.143 m.
Normal water consumption for one lockage is 12 24 225 m^3 , and thrift
lock consumption for one lockage is 127.143225 m^3. The efficiency of
the thrift lock is (24 7.43)/2470%. The saving of water per day is
18 225 12(24 7.143)819 250 m^3.
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2 0.2 4 1.6 24
4 0.6 1
2 en(K1)H
nK 1
494 INLAND WATERWAYS
