Flood Defense and Water/Sediment Management—With Particular Reference to The Yellow River - River Dynamics and Integrated River Management - page 341

shown in Fig. 6.1. As a comparison the Mazhai cross section is in the wide river reach near Huayuankou,
as shown in Fig. 6.10.

Fig. 6.9 The narrow Lijin cross section (upper, about 600 m wide), at which the most downstream hydrological station
of the river Lijin Station is located

Fig. 6.10 Mazhai cross section in the wide river reach near Huayuankou

6.2.3 Reservoirs
In the past decades, the watershed experienced marvelous economic wonders. Eleven reservoirs were
constructed in the Yellow River from 1957-2002, namely: Longyangxia, Lijiaxia, Liujiaxia, Yanguoxia,
Bapanxia, Qingtongxia, Sanshenggong, Wanjiazhai, Tianqiao, Sanmenxia, and Xiaolangdi Reservoirs.
The total capacity of the reservoirs is 55.8 billion m 3 , equal to the annual runoff of the whole watershed.
Most of the upper floods (flood water comes from the watershed of the upper and middle reaches of the
Yellow River) can be controlled with these reservoirs.
The Sanmenxia Dam is the first one built on the Yellow River, which was completed in 1960.
Impoundment of the Sanmenxia Reservoir caused siltation of the Yellow River and the Weihe River and
endangered Xian—capital city of Sha-anxi Province. The operation of the reservoir had to be altered
from storing water and trapping sediment to retaining flood water and discharging sediment, and to
storing clear water and releasing turbid water. Details of the management of the reservoir is presented in
Section 6.5.