This story is about a 20-year journey taken by the Harza Engineering Company, a global leader in the period 1920 to 2000 in the development of river projects – a byline on the letterhead being used when I joined the firm in 1968 and where I worked until 1979.
While Harza Engineering Company is the focal point as the entity that led the effort in bringing large-scale hydroelectric power development to China, it is also about a multinational team working collaboratively towards a common goal of creating a project that would generate 3300MW upon its completion.
Hydro development in China
The Ertan project on the Yalong River in Sichuan Province of the People’s Republic of China, was conceived as a potential source of clean renewable energy at a grander scale than previously developed hydroelectric projects in the region. At the time, China had embarked on several significant hydropower installations with projects up to 178m in height and the largest generator units of 300MW. In the final project configuration, the Ertan project included a 245m high double curvature arch dam, three unique spillway configurations, and an underground powerhouse housing 6x550MW generating units.
The starting point for work in China dates to the late 1970s when many internationally recognised design firms in the west were interested in the exceptionally large hydroelectric market in China. Oddly enough it was the first time anyone had heard of the Ertan project at Harza, so what followed was a bit of a surprise. Harza put together an all-star team that I had previously worked with during my eleven years at Harza, most notably on the Bath County pumped storage project.
First, Roman Wengler, who advanced the science of the double curvature thin arch dam (see article in IWP&DC, November 2022), and Arvid Zagars, with the world’s most significant expertise in powerhouse design, met with design engineers at the Chengdu Hydroelectric Investigation and Design Institute (CHIDI) and then went to the site of the proposed Ertan Dam.
After this trip, Harza put together a proposal to begin the development of the project based on a preliminary concept of a thin double curvature arch dam, along with an underground powerhouse – a departure from what was initially envisioned as a gravity arch dam and powerhouse at that toe of the dam by Harza’s Chinese counterparts. Patience became a virtue, as Harza did not hear back from colleagues in China for six more years.
Team building
An agreement was signed between the US and China in 1979 for cooperation in the development of hydropower, with engineers from both countries’ government and private sectors to visit one another. China had done its homework by looking to the engineering and geological sciences expertise available in the US for what was to become major investments in hydropower development over the next two decades.
The US government then organised two delegations; one in 1981 and a second delegation in 1983 that went to China. Harza sent Avid Zagars in 1981 and followed that in 1983 with Dr. CH Yeh, along with the participation of delegations representing different specialties from other private sector firms in the US.
On the same trip, the US team of government and private sector engineers met with Qinghua University professors on seismic design criteria, along with professors from Tianjin University on the various aspects of the project for similar discussions and presentations involving the current project status. At the end of this second delegation visit, the team presented, in Chengdu, comments on the various aspects of the project for discussion amongst many Chinese engineers of various disciplines.
The bonds between both countries in these fields were strengthened and grew through this collaboration and teamwork. After visiting CHIDI offices, the team of Chinese and American engineers traveled on the famous Chengdu-Kunming Railroad on the 14-hour ride to the city of Dukou at the confluence of the Jinsha and Yalong Rivers. The Chinese hosts took care of visitors and treated them exceptionally well, catering to their dietary needs while seeking at every turn to make their guests comfortable on the long train ride back and forth from the project site where presentations were made on the then current status of the design.
Many meetings occurred regarding the dam design; including its thickness, as might be expected, at the feasibility level of study at the site where these briefings occurred. The team made another site visit to look at topographic and geologic data, while at the same time inspecting the adits at the project site to get a closer look at the geologic features of the foundation and abutments. Subsequent detailed briefings occurred.
Along with the exploration of the features of the civil design back in Chengdu, the team visited the Dongfang Electric Machinery Factory. This factory was commissioned to build heavy machinery anticipating that hydropower projects would be constructed in the southwest part of the country in Sichuan and Yunnan Provinces.
The design and tender phase of Ertan dam
Harza got some good news during the 15th ICOLD Congress in Lausanne Switzerland in Mid-1985 as the head of the Chinese Delegation, Vice Premier, Li Edin informed Dr. Yeh they wanted Harza to do consulting work on the Ertan Project. Importantly CHIDI accepted the general layout that Harza had suggested with an underground powerhouse and thin arch dam, which departed from the original scheme of a gravity arch dam and powerhouse at the toe of the dam.
The negotiation proceeded in 1986 with a proposal and work scope involving all the project’s major features including the arch dam and powerhouse design, hydraulics and geological aspects and rock mechanics, together with construction considerations. After significant back and forth in the negotiation of the scope of work, agreement was reached with Dr Eugene Chang (Geotechnical Engineer), and Dr. Yeh (arch dam) representing Harza in the negotiation. Of importance to reaching an agreement for the design phase of the work was the prior team building engagements between Chinese and US counterparts, who worked through the feasibility work on a side-by-side basis to a common end goal. The contract was signed by Dr. Chang seven years after Wengler’s first trip to China in 1979.
The team building continued during the design phase as engineers from CHIDI came to Chicago to meet with counterpart engineers at Harza, with each guest from the client being provided with office space. One of the most interesting exercises that occurred was the iterative design development on the arch dam along with other project features. Briefly, the dam design evolved to a parabolic arch dam with the base thickness being reduced from 71m to 57m with a corresponding volume of the dam being reduced from 4.79 Mm3 to 3.83Mm3, thus reducing concrete volume by almost 1Mmm3. The reduction in dam thickness reduced the construction period by one year.
Professor Zhang Guangdou of Qinghua University said to Dr. Yeh that: “the stress analysis of arch dam is a science. The design is an art. And therefore, you are an artist.” Dr Yeh noted that was the first and only time he was called an artist.
By the end of 1986, the design of the Ertan Project was complete for tender documents. The overall project layout was accomplished for all the major project features. Harza was then awarded a second contract to help prepare the tender document which was needed to meet World Bank terms for a loan along with the World Bank requirement for international bidding.
As part of the exchange and work, three key individuals from Harza, including Dr. Jan Veltrop, Harza’s Chief Engineer (member National Academy of Engineering; President of ICOLD 1988-1991), Dr. Eugene Chang and Ken Leonardson went to Chengdu and stayed for six months working with CHIDI’s designers and draftspersons to prepare contract level drawings, quantities and cost estimates, and specifications sections. Other engineers from Harza joined them periodically to contribute to the development of contract documents. The process was tedious, with all documents going through an internal review by the Chinese government including presentation of a report of all the findings to the Ministry of HydroPower Industry.
The construction phase
Following the review, the World Bank loan application was initiated with construction starting in 1991 and ending in 1999. During construction, a Joint Venture of Harza and the Advisory Group of Norway provided support as foreign advisors with 10-20 engineers on-site for the eight-year construction period. There were two boards of experts, one of international experts and the other of domestic experts, along with a Dispute Review Board for resolving disputes between the owner and contractors.
Construction was divided into two lots, with Lot 1 being above ground construction and Lot 2 being underground work. With construction underway, the thoroughness of the CHIDI underground exploration programme during the design phase led to the discovery of no major faults or joints during foundation excavation. Construction proceeded smoothly, thanks to the completeness of the CHIDI work.
Successful resolution
During construction, one example of a successful resolution of a genuine problem concerned the diversion tunnel gates in a meeting with project owner, Ertan Hydropower Development Company (EHDC), involving the gates matching the gate slots. The diversion tunnels were 23m wide and the contractor proposed a solution to the dimensional problem of the gates that would have cost US$20M. EHDC, however rejected the contractor’s scheme and produced its own that cost $US200,000. EHDC took responsibility for the solution, thus solving the problem for 1/100 of the initial cost estimate. The scheme worked when implemented.
The first 550MW unit went on line in August 1998 while construction continued on the arch dam that was completed in late 1999. Construction continued up to the completion date with claims being processed by the contractor and being resolved by EHDC leading to completion of the project. A dedication by President Jiang Zemin (1993-2003) on one of several visits to the Ertan project demonstrated the importance of this project to economic growth in China.
The dedication occurred on 1 December 1999, with many dignitaries from Chengdu and Beijing, along with many reporters to document the completion of this massive project adding 3300MW to the grid. EHDC honored Roman Wengler and Dr. Eugene Chang of Harza as special guests, amongst the dozen or so other members of the Harza team, paying their expenses and recognising their significant contributions to the design of a project with such a profound impact in China.
Construction continues beyond Ertan
Following Ertan, projects in China reached heights of 305m for a double curvature thin arch dam at the Jinping-1 Project with 3600MW of installed capacity. Five more arch dams were constructed, all with significantly more installed capacity than Ertan including:
• Baihetan on the Jinsha River at 289m with 16,000MW installed capacity.
• Xiluodu on the Jinsha River at 286m with13,860MW installed capacity.
• Wudongde on the Jinsha River at 270m with 10,200MW installed capacity.
• Xiaowan on the Lanchang River at 292m with 4200MW installed capacity.
• Laxiwa on the Yellow River at 250m with 4200MW installed capacity.
