9.5 PRACTICAL EXAMPLES OF RIVER ENCROACHMENTS
In the preceding paragraphs, a series of conceptual cases were discussed. Each case
considers the interactions between the river and the encroachment over a period of time. In
general, the particular practical examples presented in this section are not as complex as
some of the earlier conceptual cases. For example, there is no consideration of water
resources development throughout the basins, including construction of reservoirs
transmountain diversions, and so forth.
9.5.1 Cimarron River, East of Okeene, Oklahoma (Example 1)
The bridge and a rock dike on its north abutment were built in 1934 (Figure 9.2a). A high
discharge year in 1938 caused the south bank to erode. A Kellner jetty field was installed to
prevent further erosion of the bank. The jetty field was ineffective due to the lack of debris and
suspended sediment load. A large flood in 1957 spread out over the floodplain in several
places. After the flood, seven timber pile diversion units and a riprapped dike were installed in
the old jetty field location to prevent future damage to the highway (Figure 9.2b). As of 1968,
the south bank had been held in line by the timber pile diversion structures and the dike
(Figure 9.2c).
9.5.2 Arkansas River, North of Bixby, Oklahoma (Example 2)
The bridge was built in 1938. A Kellner jetty field was installed on the north bank in 1939 to
protect the north bridge abutment (Figure 9.3a). In 1948 minor floods eroded the south bank.
A Kellner jetty field was installed to prevent further erosion (Figure 9.3b). Some time after,
riprap was put on the south bank up- and downstream of the jetty field (Figure 9.3c). In 1959,
a 50-year frequency flood eroded the north bank and washed out a section of the north
approach to the bridge. The flood also washed out two sections of roadway further north on
the floodplain. The approach was rebuilt and riprap was installed on the embankment. A
riprapped spur dike (guide bank) was also constructed just south of the north abutment. Five
pile diversion structures were built to prevent further erosion of the north bank (Figure 9.3c).
As of 1968, the south bank has remained stationary, and the north bank has filled (Figure
9.3d).
9.5.3 Washita River, North of Maysville, Oklahoma (Example 3)
In 1949, floods washed out the north span of the bridge. Also, both banks upstream from the
bridge were damaged. A temporary structure was installed in place of the north span of the
bridge. In October of 1949, two Kellner jetty fields were completed upstream from the bridge
to provide bank protection (Figure 9.4a). In 1950, a new bridge was constructed just
downstream from the old bridge. State Highway 74 was realigned to conform to the new
bridge. In eight months of operation, the Kellner jetty field on the northeast bank had
completely silted in. This was largely due to the clay content in the suspended sediment and
the large amount of drift in the stream (Figure 9.4b). The floods of 1957 did very little damage
to the new bridge site or the banks. Floods in 1968 and 1969 have caused bank erosion on
the north bank upstream of the jetty field which could eventually cut in behind the jettyfield
(Figure 9.4c).
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