Comparison of Three Gorges specifications in Canadian feasibility study with those chosen by Chinese officials

By Other News Sources on January 12, 2011 • ( Leave a comment )

(January 12, 2011) Comparison of specifications recommended by the Canadian engineering feasibility study[1] with those chosen and built by the Chinese Government for the Three Gorges dam.

Item	Unit	Chinese Study	Canadian Study	Note

NPL	metres	175 metres	160 metres	The World Bank, in its review of the Three Gorges Water Control Project Feasibility Study, Volume 1,Feasiblity Report, August 1988, CIPM Yangtze Joint Venture feasibility study (page 4-1) said: “The feasibility report contains evidence to indicate that increasing the NPL from 160 m to 170 m and higher would not be an economically viable proposition. This would not substantially increase flood control benefits and the incremental cost most likely would exceed the additional economic benefits. Resettlement problems at higher pool events may become unmanageable.” See here.
Crest elevation	metres	185 metres	185 metres
Flood Control Level	metres	145 metres	140 metres
Maximum Flood Control Operating Level	metres	180.4 metres	181 metres
Generating capacity	MW	18,200 MW	16,750 MW	18,425 if 225 MW of the new underground power station is included
Flood control capacity	Billion m3	22.15	31*	Chinese: high 175 m and low 145 mCanadian: high 181 m** and low 140 m
People to move		Planned: 1,130,000	Planned: 727,000	Actual: 1,400,000
Cost	Billion yuan RMB	Estimated price in 1986 yuan: 29.828Estimated price in 1993 yuan: 90.09	Estimated price in mid 1987 yuan: 24.6	Official Chinese Government cost: Static Investment: 90.09 (at 1993 price level)Dynamic Investment: 200Independent cost estimates: Ten members of the CPPCC: between 200 and 500 (Dynamic Investment) 1) Qiao Peixin: 320 (or US$40; Dynamic Investment) 2) Lu Qinkan: 600 (or US$75; Dynamic Investment)

* “The flood control storage of 31 billion m3 is fixed by the dam crest level at EL. 185 m and the flood control level at EL. 140 m.” See page 1-1, Three Gorges Water Control Project Feasibility Study, Volume 1,Feasiblity Report, August 1988, CIPM Yangtze Joint Venture. Also see “Flood control storage is 31 billion m3 between 140 m FCL (Flood Control Level) and 181 m MFL (Maximum Flood Control Operating Level).” See p 1-12, Three Gorges Water Control Project Feasibility Study, Volume 1,Feasiblity Report, August 1988, CIPM Yangtze Joint Venture.

Definitions:

NPL (normal pool level) or Normal water surface elevation: The lowest crest level of overflow on a reservoir with a fixed overflow level (spillway crest elevation). For a reservoir whose outflow is controlled wholly or partly by movable gates, siphons, or other means, it is the maximum level to which water may rise under normal operating conditions, exclusive of any provision for flood surcharge.

Crest: The top surface of the dam. A roadway may be constructed across the crest to permit vehicular traffic or facilitate operation, maintenance, and examination of the dam. Also, the high point of the spillway control section.

Crest elevation (crest of dam, top of dam, dam crest): The elevation of the uppermost surface of a dam, usually a road or walkway, excluding any parapet wall, railing, curb. etc. The crown of the roadway or the level of the walkway, which crosses the dam. On embankment dams, the crest of the dam is the top of the embankment, not including camber, crown, or roadway surfacing.

Elevation: The height of a point above a plane of reference. Generally refers to the height above sea level.

Prepared by Probe International, January 12, 2011

[1] CIPM Yangtze Joint Venture (CYJV), Three Gorges Water Control Project Feasibility Study. 1988.

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Further readings and updates:

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