Lock & Dam 24


Construction on Lock and Dam 24 began on July 20, 1936 and was finished on March 12, 1940. A major rehab of the lock and dam was completed in 2005. This work consisted of replacing a large portion of the concrete in the lock chamber walls, walkways and work areas. Also, new gate and valve machinery was installed elevating the electrical components above the 1993 flood levels.

The dam consists of 15 fully submersible tainter gates. These gates pivot vertically to control water flow. In times of high water, these gates are raised completely and the river flows almost unimpeded, allowing a more natural flow of the river.

The lock chamber is only big enough for a half size tow (a normal tow is one towboat pushing 15 barges). The barges going through this lock must perform a double lockage. During a double lockage, the first set of barges (up to nine) are disconnected and put through the lock chamber. Since these barges are no longer connected to a towboat, they are pulled through using a tow-haulage (cable and hoist system). After the barges are locked through, the rest of the tow locks through and rejoins its entire load. This process can take up to two hours to complete. Recreational boats must also lock through the lock on their journeys up or down the river.

Vital Statistics

Location: Clarksville, Mo.
Mississippi River Mile: 273.4
1st Day of Operation: Mar. 12, 1940
Average lift: 15 feet
Pool size: 29,750 Acre Feet
Pool length: 27.8 miles
Lock characteristics:
Single Lock, 600 feet long, 110 feet wide
Dam Characteristics:
1,340 feet long, 15 Tainter Gates
Phone number: (573) 242-3524
Marine Radio: 14

Nine-Foot Navigation Channel

Located in Clarksville, Missouri, Lock and Dam 24 is part of the Upper Mississippi River Nine Foot Navigation Project. The Project, authorized by the Rivers and Harbors Act of 1930, created and ensured a nine-foot deep navigational river channel.

On the upper Mississippi River, a total of 29 lock and dam systems were constructed, forming a stairway of water from Minnesota to Illinois. From the first lock and dam at Minneapolis-St. Paul, Minnesota to the last one at Granite City, Illinois, there is a drop in elevation of 420 feet. The locks are necessary at each of the dams to allow boats to navigate from one pool (the water backed up behind each dam) to the next. These locks were constructed to aid in navigation only, they were not designed for flood control.

On the lower Mississippi, the river does not need locks and dams because, with the addition of the Missouri, Illinois, Arkansas, Ohio, and other rivers, it is naturally wide enough and deep enough for navigation.

Locking Process

The lock chamber consists of four miter gates (two at each end of the chamber), and four valves (two at each end). All boats wishing to pass through a dam must lock through the lock chamber, even during open river conditions.

Lockage is completed by using a system of valves to raise and lower the water level in the lock chamber. This is an elevator system for boats, raising or lowering them to the same level as the pool they want to get to. There are two sets of valves, the filling valves (located at the upper pool) and the emptying valves (located at the lower pool). The filling valves are opened to allow water to enter the chamber, making it the same height as the upper pool, and the emptying valves are opened to allow water to drain out, making the chamber the same height as the lower pool. During the process, no pumps are used; the chamber is operated solely on gravity.

Annual Tonnage

Year Tonnage Lockages
2009
26,682,701
4,282
2008
23,133,551
3,616
2007
30,145,700
4,816
2006
31,061,559
4,642
2005
28,932,976
4,403
2004
27,883,604
4,370
2003
33,761,938
5,268
2002
38,864,614
6,196
2001
34,785,352
5,601
2000
38,697,993
6,282
1999
39,296,994
6,504
1998
34,747,480
5,767
1997
33,614,330
5,835
1996
36,181,599
6,481
1995
37,540,528
6,537
1994
30,735,288
5,331
1993
26,581,272
4,657
1992
39,423,782
7,078
1991
37,595,771
6,897
1990
42,352,920
7,670
1989
36,137,676
6,719
1988
37,885,828
7,060
1987
35,313,874
6,459
1986
28,162,425
5,199
1985
26,101,054
5,040
1984
35,962,865
6,536
1983
37,345,441
7,039
1982
32,731,049
6,264
1981
34,002,095
6,729
1980
32,731,049
6,601
1979
28,562,788
Na
1978
28,928,612
5,893
1977
25,057,500
5,248
1976
24,588,373
5,386
1975
23,713,451
5,058
1974
24,522,995
5,157
1973
22,940,935
4,914
1972
24,941,149
5,384
1971
21,563,788
5,250
1970
22,209,505
4,938
1969
18,371,594
4,344
1968
16,663,104
4,688
1967
16,312,126
4,211
1966
15,915,016
4,078
1965
13,312,470
3,585
1964
13,312,470
4,084
1963
12,611,627
3,827
1962
10,865,245
3,801
1961
9,638,452
3,367
1960
9,711,261
3,408
1959
9,180,898
3,398
1958
8,446,256
3,386
1957
7,437,070
3,288
1956
6,783,763
3,146
1955
6,505,230
2,001
1954
5,649,694
2,437
1953
5,053,533
2,337
1952
4,042,095
2,028
1951
4,199,346
1,991
1950
4,305,665
2,260
1949
3,645,372
2,553
1948
3,224,357
2,179
1947
3,149,689
1,706
1946
2,977,872
1,818
1945
2,029,925
1,214
1944
1,878,290
1,120
1943
1,669,539
1,051
1942
1,968,730
1,410
1941
1,975,878
2,214
1940
1,578,624
1,719