dam site is at Sanduoping,Yichang City, Hubei province. The total
catchment area is about 1,000,000 square meters and there is
451,000,000,000 cubic meters of average annual runoff.
At the location of the Sandouping dam site, the river valley is relatively
open and broad, with a small islet known as Zhoubaodao in the river, which
is favorable for a river diversion scheme with phased construction. As
regards communications, there is a railway to Yichang and a waterway to
the dam site. A 26 km-long expressway has also been constructed from
Yichang to the dam site. The bedrock at the dam site is sound, intact
granite with a compressive strength of 100 developed. The rock mass has
only very slight permeability.
The main elements of the project are the dam, two power plants, and the
The spillway dam section is in the center of the river channel, that is,
on the original main river course, while the intake and non-overflow
sections are arranged on each side. The powerhouses are to be located at
the toe of the intake section. The navigation structures are on the left
The dam is of the concrete gravity type. The total length of the dam axis
is 2309.47m, with the crest elevation at 185 m, and a maximum height of
The spillway section is 483m long, with 23 bottom outlets and 22 surface
sluice gates. With a maximum discharge capacity of 102,500 cubic meters,
the project is designed to discharge the probable maximum flood PMF.
The two powerhouses will be at the toe of the dam. Fourteen sets of
generating units will be installed in the left bank powerhouse, and 12
units in the right one. The turbines will be of the Francis type each with
a rated capacity of 700 MW.
There will be 15 transmission lines, with 500 kV AC lines to Central China
and Chongqing and ± 500kV DC lines to East China.
The permanent navigation structures consist of the permanent ship lock and
a ship lift. The design capacity for annual one-way navigation is
The ship lock is designed as a two-way, five-step flight of locks; each
lock chamber is 280*34*5m.capable of accommodating a 10,000 t barge fleet.
The ship lift is designed as a single-stage vertical hoisting system with
a ship container sized at120*18*3.5m.capable of carrying one 3000 t
passenger or cargo boat each time.
of the dam
The total construction period will be 17 years, with the three stages
being as follows:
Preparation and first stage 5 years (1993 to 1997)
Second stage (construction) 6 years (1998 to 2003)
Third stage (construction) 6 years (2003 to 2009)
River diversion is being phased, and the construction schedule is divided
into the three stages.
In the first stage, the part of the river on the right side of the islet
has been enclosed. Advantage was taken of the islet to build an earth- and
rockfill cofferdam. In this stage, the open diversion channel was
excavated and the longitudinal cofferdam was constructed. Meanwhile,
construction of the temporary shiplock was being finished on the left
bank. During this construction phase, the river flow and navigation have
continued to be through the main river course.
In the second stage, now under way, the transverse cofferdam is being
constructed, to form, together with the completed longitudinal cofferdam,
the second stage construction pit, where the spillway, the intake dam and
the powerplant on the left bank will be built. Simultaneously, the
permanent shiplock and the shiplift are being constructed on the left
bank. In this stage, the river flow will be diverted through the diversion
channel, and the boats will be able to pass either through the open
channel or the temporary shiplock.
In the final stage, the third stage cofferdam is to be built in the open
channel, and the reservoir impounded up to el.135 m. The left bank power
station and permanent shiplock will then be put into operation. In the
meantime, the third stage cofferdams, together with the longitudinal
cofferdam, will form the third stage construction pit so that the right
bank dam and powerplant can be built. During this period, the river flow
will be discharged through the outlets in the spillway dam, and the boats
will pass through the permanent shiplock.