6 Conclusion
The comprehensive function value of the channel connectivity increases
gradually with time, so the channel connectivity increases from 1955 to
2015 in the Jingjiang River. The average values of —Shashi-Jianli
reach, Jianli-Luoshan reach and Zhicheng-Shashi reach are 0.97, 0.99 and
1.00, respectively.
In the Zhicheng-Shashi reach, the comprehensive function value of the
channel connectivity decreased from 1967 to 1972, with a range of
0.72-0.85, which may be caused by river straightening. Then, the value
increased due to the impoundment of the Gezhouba Dam after 1980.
However, the values were basically greater than 1.0 since 2003, which
shows that reservoir construction will improve downstream channel
connectivity.
In the Shashi-Jianli reach, the comprehensive function value of the
channel connectivity fluctuates across 0.85 from 1965 to 1972, and the
range of the value was 0.9-1.0 from 1972 to 2002. After the impoundment
of the TGD in 2003, the value continued to increase with good channel
connectivity.
In the Jianli-Luoshan reach, the change in channel connectivity can be
divided into two processes: the comprehensive functional value of the
channel connectivity fluctuated across 0.87 from 1956 to 1987; then, the
value increased and ranged from 0.9 to 1.1 after 1988. In addition, the
construction of the TGD has little effect on the channel connectivity of
the Jianli-Luoshan reach because the influence of reservoir regulation
is reduced by the upper reaches.
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Data Availability Statement : Research data are not shared