Geoscience Reference
In-Depth Information
Lock and Dam No. 1 consists of an 84-feet by 685-feet lock and dam structure
located at pre-project river mile 45 in east central Louisiana. Shortly after con-
struction, Lock and Dam No. 1 experienced significant sediment deposition during
the high water season that resulted in structural damage. Though sediment depo-
sition was expected, the amount received silted the lock chamber rendering it
inoperable. The continued operation of the lock during the high water season
resulted in damage to the lower miter gates. Structural modifications had to be
made in order to either reduce the amount of sediment deposition or at least
relocate the deposition into areas assessable by maintenance dredges. Dikes were
constructed in the upper approach channel, and the riverside lockwall was elevated
as well as extended to manage sediment deposition.
Lock and Dam No. 2 consists of an 84-feet by 685-feet lock and dam structure
with an uncontrolled overflow section and fixed guidewalls, located approximately
14 miles downstream of Alexandria. To identify and reduce potential sedimen-
tation problems in this lock, a series of physical and numerical models were
performed; one sediment control dike extending downstream from the riverside
lockwall, three reverse angle dikes extending from the right descending bank
immediately downstream the bank, and narrowing of the approach channels to
increase velocities were installed. After much investigation and study, the
Vicksburg District designed and installed a high-velocity jet system to resuspend
the unwanted sediments at the miter gates. This measure has been extremely
successful in reducing sediment depositions at the upstream miter gates. The
sediment management measures developed for Locks and Dams No. 1 and 2 were
subsequently incorporated into the design of Locks and Dams No. 3, 4, and 5,
which included moving the downstream guidewall from the landside of the lock to
the riverside, installing a permanent more elaborate jet system for either the upper
miter gates or both sets of miter gates, and engineering the river channel cross
section to more closely approximate the natural river section. The five sets of
Locks and Dams control the flow of the lower Red River, raising it a total of 141
feet. The locks can accommodate a total of six barges (two across by three
lengthwise).
Conclusions
Throughout its history, significant interest has been placed on navigation of the
Red River and settling its valley. The Red River Raft presented many challenges to
those wishing to use the Red River as a path to connect the eastern US to the west.
This Raft was first encountered by Native Americans and described in writings by
Europeans. It is believed that Spanish explorer, Hernado de Soto's expedition first
explored the region in the early AD 1540s; it is likely that the raft had been in
place for about 1,500 years. In AD 1714, a French settlement was established at
the toe of the Raft; this territory was later purchased by America. Clearing of the
raft was begun in AD 1832 and was seen as an answer to westward expansion. A
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