Environmental Engineering Reference
In-Depth Information
FIGURE 3.10 Measuring streamlow through a V-notch weir. (Photograph by Alan Cressler, USGS
Multimedia Gallery.)
Wing dikes, which are common on many of our river systems, are rock structures extending from
the riverbank out into the river channel for distances up to 1 mile or more. Dikes help to reduce
sedimentation in the main channel by constricting lows and increasing velocities. Dikes can protect
banks from erosion. They can also form protected areas, often with plunge pools, that provide ish
habitats. Dikes are typically placed in straight reaches and long radius bends. While they are com-
monly used in wide and shallow streams, dikes are also used in large rivers to increase their depth
for navigation and to stabilize banks and channel alignment.
Bendway weirs are similar to a dike but are directed at an angle to the low. Bendway weirs
were developed by the U.S. Army Corps of Engineers to increase the channel width in bends on the
Mississippi River to improve navigation conditions and to reduce maintenance dredging require-
ments (Derrick et al. 1994). Bendway weirs are also commonly constructed on smaller streams
and rivers (Figure 3.11) as a streambank protection measure, also providing a substrate for benthic
organisms and cover for ish (Biedenharn et al. 1997).
FIGURE 3.11 Bendway weirs on Harland Creek. (From Biedenharn, D.S., Elliott, C.M., and Watson,
C.C., The Stream Investigation and Streambank Stabilization Handbook , U.S. Army Corps of Engineers,
Waterways Experiment Station, Vicksburg, MS, 1997.)
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