Professor Qi Pu was invited to give a talk on the recent flood
risk of the lower Yellow River after Xiaolangdi Reservoir was operated in 2000.
The abstract of my paper is:
Representing the most important
influence on the land-ocean sediment fluxes in the world, dams and reservoirs
alter the continuity of sediment transport and decrease the supply of sediment
to downstream reaches. After the operation of Xiaolangdi Reservoir, channel bed
of the lower Yellow River has been strongly eroded, and the discharge capacity
increased gradually. In recent decades, the trend of flow and sediment alters
due to the massive harnessing projects on the upper and middle reaches. The
amount of sediment entering the lower reach has been gradually reduced
significantly, and there are no big flood events. There are no floods exceeding
the warning water stage, thus the flood control situation of the downstream
reach has changed dramatically. In addition, the volume of sediment which is
transported to the estuary has also been greatly reduced, so as the siltation
and extension at the river mouth, thus its impact on the upper reaches can be
ignored. With the multi-year sediment regulation of Xiaolangdi Reservoir, we
can take full advantage of sediment discharge by flood to further scour the
riverbed of the lower reach. The current downstream reach becomes one of the
most secure rivers in the world, which will inevitably affect the future
prospects of governing the Yellow River basin. In order to prevent situations
similar to the excessive river management in North China, which can cause the
environment of the lower Yellow River to deteriorate, we should maintain the
healthy life of the river, and it is necessary to adjust the scale of
harnessing projects on the upper and middle reaches, as well as to construct
Taohuayu Project in the lower reach for better control of floods.
The presentation was
well-received by the audience, and the participants from the conference joined
in-depth discussion after my talk. Everyone was very interested in the reasons for the great changes in the flooding of the lower Yellow River after the completion of Xiaolangdi Reservoir. This is also a good learning opportunity and communication effect for young hydraulic workers and researchers.
