The river diversions achieved recently at the Xiaolangdi and Three Gorges hydropower project sites were acclaimed loudly by the Chinese media. Time and cost overruns are common with major construction projects ?the Channel Tunnel between England and France being one example ?so the government was justifiably proud in the deadlines being met.
River closure at the Xiaolangdi site near Luoyang in Henan province was achieved on October 28 in the presence of Premier Li Peng and Liu Maosheng, Minister for Water Resources. All operations went smoothly and the river now flows through diversion tunnels, allowing for completion of the 154 metre-high main dam.
River diversion at the Three Gorges Project was achieved on November 8, when the main channel of the Yangtze River near Sandouping, Hubei province, was closed; a large diversion canal had already been in use for navigation for some weeks. The first phase of the world's largest power project has thus been completed on time, indicating that the whole project is on schedule.
Xiaolangdi half complete
Huge political capital has been invested in these projects. According to Premier Li Peng, speaking shortly before diversion of the Yangtze, the event would "demonstrate to the world that the Chinese people have the ability to build the biggest and most beneficial irrigation and hydro-electric project in the world at present".
China is the main hope of future hydro business for international and domestic equipment suppliers and contractors. Early this year, a survey by Hydropower and Dams journal showed that there was 634GW of hydro capacity in the world, generating 2,460TWh a year. The 84.7TWh-a-year Three Gorges project represents an increase in the world's current hydro capacity of more than three per cent.
At the end of 1996 China had 55.6GW of hydro capacity, the fourth highest total in the world. The Three Gorges project alone will boost China's total by one-third.
The Xiaolangdi site is in a large gorge along the middle tract of the Yellow River. A workforce of around 12,000, including 1,000 foreign personnel, worked around the clock to achieve successful river diversion soon after the end of the summer flood season. Construction of the whole project has now passed the 50 per cent stage.
The project combines the functions of flood and ice control with irrigation, water supply, sediment management and power generation. It will regulate the flow of the Yellow River along 800km, protecting plains inhabited by 120m people. The hydropower generated at Xiaolangdi by the 1,800MW hydro plant will be worth about US$170m a year. The dam will in-crease crop yields on about 2m hectares of land and make additional water avail-able during dry months to cities such as Qingdao in Shandong province..
The main dam will have a volume of about 50m cubic metres, believed to be the largest volume dam under construction in the world. The main civil works, be-gun in 1994, are expected to be completed in 2001.
The project's 12.8 cubic km reservoir will extend for 130 km. It is designed to trap sediment for the first 20 years of operation, and then to reach a state of equilibrium. A complex system of 15 tunnels will make it possible to flush sediments by creating controlled floods in the main channel. On the negative side, about 170,000 people are having to be resettled, and any inability to flush sediment couldshorten the useful life of the scheme.
The on-time river closure was of extreme importance. The rainy season runs from mid-June to mid-September, when rainfall near the site and upstream may cause floods. River closure had to take place soon after the end of the rainy sea-son to maximise the time available during the dry months to carry out water-proofing of the upstream cofferdam. Immediately after the closure, Yellow River Contractors had to increase the height of the upstream cofferdam to allow for di-version of the river through the diversion tunnels and to provide safety in case of minor floods.
The upstream cofferdam must now be heightened quickly to its final elevation, ready for the 1998 flood season. This is a very challenging task, since aspects such as foundation preparations and jet grouting works for underground sealing play a vital role. The quality of the foundations is paramount. Jet grouting is a specialised technique requiring the drilling of carefully aligned holes and the injection of grout under pressure. The higher the quality of work, the less leakage there will be, facilitating the task of maintaining a dry work site behind the cofferdam.
Costs of delay
While work at the Three Gorges involves only Chinese companies, Western contractors are working at Xiaolangdi. Any de-lay in river closure would have jeopardised the timely completion of the up-stream cofferdam and the protection from flooding of the construction site down-stream, with all sorts of serious possible consequences, such as dam breach, loss of life and delays.
From the owner's point of view, on time river closure was critical to on-time completion of the main dam. The cost of delays in terms of hydropower generation can be calculated easily; but, probably more important, a delay of just a few weeks could have led to the main dam being put into operation one flood season late, delaying the dam's principal purpose of flood protection.
The government is developing the US$4bn multipurpose project with financing, in part, through credit and loans from the International Development Agency and The World Bank. It is one of the Bank's largest commitments to China, with lending of about US$1bn earmarked. More than US$570m of this has been disbursed.
The Bank has estimated the project's economic rate of return at about 18 per cent, including the flood control and power benefits, as well as an increase in production for about 4.5m farming families. Unlike at Three Gorges, the US Eximbank has joined the World Bank in supporting the project by providing export credits.
The on-time river closure at the multipurpose-Three Gorges Project was also critical to the overall schedule. However this project, which is being built by Chinese contractors, still has at least 12 years of construction ahead and there are many important engineering and financial hurdles to overcome.
Three Gorges on schedule
The Three Gorges Project is China's largest construction project since the Great Wall, with an official cost estimated at Yn200bn (about US$26bn). It is much larger than any other major power project in China and bigger than any other hydro project in the world.
The Three Gorges Project will have an annual output of 84.7 TWh from 26 generating units ?the equivalent of 10 additional 1,800MW thermal plants, which would burn 50m tonnes of coal a year. Of the 39.3bn cubic metres storage capacity, 22.2bn cubic metres will be for flood control, so that the long reservoir will help protect the population of millions down-stream from a one-in-a-100-year-flood rather than just the current 10-year-flood. Navigation in the upper reaches of the Yangtze will also be improved, allowing for an increase in the annual shipping capacity from 10m to 50m tonnes, with 10,000-tonne vessels able to journey all the way to Chongqing, boosting trade into China's interior.
The project also has well-known negative repercussions. It will inundate 24,000 hectares of farmland, and require the eventual relocation of about 1.2m people. The slower flow of the Yangtze and higher water levels will reduce water quality and aggravate the shoreline. The dam will cause slower flow velocities in the river, reducing the natural purification effect of the river flow. However, the overall reduction in water quality should not be too significant. Perhaps more important will be the change in natural landscapes and the inundation of historical sites.
There are also long-term concerns over the extent to which sedimentation will affect the usefulness of the scheme. The stability of the permanent ship-lock walls has also been questioned, as well as the level of risk to the cofferdams during construction. Construction of the phase two cofferdam, directly behind the closure dike, now presents one of the most difficult tasks of the project, in terms of materials quality and the need for a large concrete cut-off wall. The 80 metre-high dam needs to be built to a fight schedule by June 1998, and there are concerns over its size and the implications should flooding lead to water levels flowing over the top of the dam.
So far the Three Gorges Project is on schedule and within budget. One factor which has helped with the timing is the absence of Asian Development Bank or World Bank funding. These institutions usually undertake extensive and lengthy environmental assessment procedures. The use of entirely Chinese contractors has also simplified matters. The project is being funded from multiple sources, mostly from a levy on power sales nationally and using revenue from the Gezhouba hydro project downstream. The State Development Bank is providing loans, while revenue from the sale of power from the first units, which should be commissioned progressively after 2003, will part fund the third phase works. Export credits, commercial loans and bonds will be used to fill the funding gap in the peak years of investment during stage two.
Tight profit margins
A massive construction programme is under way in Sichuan and Hubei to build replacement towns, roads and factories for those to be relocated. This new construction and compensation should absorb about 45 per cent of the total project costs. Some 100,000 people have so far been re-located. About 50,000 migrant workers are employed at the site, with more working on the new infrastructural projects in the reservoir area.
The government is driving hard bar-gains with those foreign companies seeking to provide equipment, with minimal profit margins. While most foreign companies have become hard-nosed about taking on Chinese infrastructure projects which don't pay commercial returns, the shortage of hydro activity outside Asia and Latin America means that many foreign companies have been prepared to become involved in this project simply to keep factories running and staff employed. In addition, there is the prospect of future involvement in China's many.
The developer of Xiaolangdi is Yellow River Water and Hydropower Development Corporation, a state-owned entity belonging to the Ministry of Water Resources. The consultant is Canadian International Project Managers, comprising Acres International and SNC-Lavalin Inc in a joint venture with BC Hydro Inter-national, with the participation of AGRA-Monenco. Yellow River Con-tractors is the contractor for the main dam and was responsible for the closure works. It is a Sino-European joint venture led by Impregilo of Italy. The diversion tunnels were completed earlier by Chinese-German-Italian Con-tractors, a joint venture of Ed Zueblin AG (leader), Strabag International and Wayss & Freytag (all of Germany), Spie Batignolles (France), Salini Construttori (Italy) and Construction Bureaux No. 7 and 11 (China). The power facilities were awarded to Xiaolangdi Joint Venture, comprising Dumez of France, Philipp Holzmann of Germany and China's Construction Bureau No. 6.
large hydro projects which are on the horizon. China has by far the world's biggest construction programme under way.
Contracts for the first 14 generating units were awarded in August to two consortia involving European and North American engineering companies, worth US$420m and US$320m. Harbin Electric Machine and Dongfang Electric Ma-chine of China were sub-contracted 31 per cent of the total contract price. A high level of technology transfer was demanded, as well as financing guarantees. Export credits and commercial loans of 15 to 20 years duration are being provided by the successful consortia. It is planned that Chinese companies will manufacture the final 12,700MW units for the right bank hydropower station during phase three. This represents double the capacity of the largest units so far produced domestically.
Beijing has dedicated massive financial and material resources to ensure the smooth progress of these two huge hydro projects. However the challenges ahead, particularly at Three Gorges, mean they will remain under the international spotlight of those eager to see how the engineering, social and economic challenges will be tackled.