In Memory of Professor Cao Chusheng: A Life Dedicated to Hydraulic Engineering

At 7:00 pm on November 19, 2017, the 91-year-old pioneer of modern dam design in China, a famous hydraulic engineer and Academician of the Chinese Academy of Engineering, Professor Cao Chusheng of Tianjin University, passed away in Beijing. The 81-year-old former vice general manager of the China Three Gorges Project Development Corporation Yuan Guolin came to bid farewell to his old friend early in the morning, "I have said before that, for people who do hydraulic projects like us, chasing the rivers throughout life, regardless of the ups and downs. Chief Cao is our model." From the Huaihe River, to the Yellow River, and to the Changjiang River, Cao traveled the mountains and rivers.

A life dedicated to hydraulic engineering

In 1948, Cao graduated from Shanghai Jiao Tong University’s Department of Civil Engineering and stayed on as a teaching assistant. The then demand of the country ignited the heart of this young college assistant. He led the students out of the university and into the fiery governance site of Foziling. This chance created an enduring bond with water conservancy, and made his life "flow" together with the motherland's water conservancy and hydropower construction program.

He pioneered a number of "firsts" in the history of China's water conservancy projects: the Foziling Multi-arch Dam, the Mozitan Double-Pier Dam and the Xiang Hongdian Gravity Arch Dam which were designed in the 1950s. These three designs have different features, which were national initiatives; first as a design chief engineer, designing the Yellow River Salt Lake Gorge Project, which is the first power station on the Yellow River hydroelectric power station in the 1960s; then in the 1970's, presiding over the design of the Bailong River’s Bikou dam, which is the first Seat large-scale crushed earth and rock dam in China, and withstood the test of the 2008 Wenchuan earthquake.

The Panjiakou water conservancy project is a Water Diversion Project from the Luanhe River to Tianjin, and this design was presided over by Cao in the 1980s. The project was China's first large-scale hybrid energy storage plant, and the first-stage of the project has saved more than 50 million yuan for the country, winning the national Excellence in Design award. More importantly, many of the dams he designed are well-known water conservancy projects in China, which still to this day work well. He deserves to be called the "country's first ‘master of engineering' in China".

The Foziling Reservoir was the first design of a dam that Cao was involved in. He had just left the school teaching post and went into dam design, where Cao’s endeavors and his indomitable fighting spirit would leave an indelible mark on the nation. At that time, under the mentorship and support of Wang Huzhen, a well-known water conservancy expert in China, the Foziling reservoir engineering headquarters had just been established, he organized the Dam Design Team to design the Foziling Multi-arch Dam. At that time, the dual-arch dam had never been built in China, and had just recently appeared in the world. Cao, was a bold pioneer. At that time, there was no information about arch dam in domestic literature, so the team read and studied foreign texts for information. They learned from books and they consulted or acquired from other engineering and technical personnel and workers.

To increase their knowledge, engineering and technical personnel also organized on-site study classes, having an engineering class in an empty conference room every night, which was called "Buddha Ridge University." Everyone was both student and teacher. In addition to lectures by Wang Huzhen, Zhang Guangdou and Gu Dezhen, many young people also held lectures. Wang Huzhen recalled: "Cao Chusheng's content was the most effective among them. After his lecture, everybody knew how to calculate the stress in the arch dam and the stack, and Caoalso systematically reviewed the material mechanics and structural mechanics we had learned." Led by Cao, the young engineering and technical personnel calculated the structural mechanics of various loads clearly and proved that the strength of these stress-ability structural materials was competent, after completing many hours of theoretical analysis and calculation. As a result of these proofs, the technical design department could issue construction drawings and the Public Works Office could issue orders to pour concrete for the dam.

In April 1954, the Foziling Reservoir was finally completed and became the first reinforced concrete dam in China. Even foreign experts gave their approval and praised the Chinese engineers. As a result of his outstanding contribution to the Foziling project, Cao was awarded the title of the first-class hero, and later he was selected as one of the advanced producers of agriculture and water conservancy and the advanced producer of the country. In 1956, he joined the Chinese Communist Party with honor in the Huaihe Commission.

Starting with the Foziling Dam, Cao demonstrated his outstanding skill in structural mechanics calculations. After years of engineering practice, Cao Chusheng gradually solved many problems of high dam construction, and advanced a "rigid body limit equilibrium” calculation method to solve the non-slip stability problems between dam and dam foundation; he made use of basic principles of dynamics and successive correction of a combination to solve arch dam earthquake stress problems; using the impermeability and frost resistance of the full cross-section "zero slump" concrete technology, he improved concrete resistance and reduced costs. These innovative approaches have not only been proven by practice, but have also been adopted and developed by many projects. In the last century, when there were only manual calculators, these innovative approaches have greatly enhanced the effectiveness, quality and safety of dams.

Quality is the lifeblood of the project

In the water industry, Cao is widely known for his strict requirements and meticulous work. In the specific design process of the project, a small number, a less obvious connection, would bring immeasurable impact on the entire project. He often said that water conservancy projects cost a considerable investment and the projects have a bearing on people's lives and property. As a result, even if the problems in the design of projects were very minor, they could significantly affect the quality of dam construction and the scale of investment.

He was not only seeking to increase perfection in design, but also enforcing strict quality control during construction. In some cases, the construction unit did not follow the design requirements during the creation of a building. As soon as he discovered this lapse, he would try his best to correct the mistakes, and sometimes he even fought the contractor until the construction unit resumed construction according to the design requirements. Many construction units were respectful and intimidated by Cao Jusheng's "stubbornness," but after many years his insistence and decisions at that time were vindicated.

In the 1960s, when the Bikou project site on the Bailong River came into being, the construction did not go well during the "Cultural Revolution", and the quality often did not meet the requirements. With the spirit of responsibility for the motherland, the people and future generations, Cao led engineering and technical personnel, who regarded the power station construction as their own business and life’s work, and upheld the exact quality standards and risked the destruction of their personal reputations. They withstood the pressure and argued for rescinding unreasonable or wrong decisions and those which did not meet the quality requirements or construction standards.

He Bosen, a former professor of the Water Conservancy and Management department at Tianjin University, recalled that, during the construction of Bikou hydropower station, there was a backfilling of the clay core wall during a massive rain storm. At that time the conditions of the site did not meet the requirements; the clay was drenched, so the moisture content of clay had increased. If the clay was used for backfill, it would not meet the standard. Cao Chusheng demanded a quick work stoppage and cessation of backfill operations. After the rain stopped, the water in the foundation pit needed to be removed. Only then could it be backfilled. At that time the person in charge of the project did not agree, saying, "Fill in the line, and why dig it out?" Cao Chusheng stood firm in his insistence on the excavation and water removal. He was answered by the person in charge, "Then you dig it by yourself." Cao Chusheng immediately returned to the design team, calling on all engineering staff to stop work, bring the tools needed to drain the water from the area. It was Cao Chusheng's insistence that ensured the quality of the project. He Bocheng commented on Cao Chusheng that: "Intellectuals must have the conscience of intellectuals. On the key issues, especially the technical issues, they should adhere to the principle, should not follow the call and could not bow to the pressure of power. Cao was an excellent example for this."

Designers who arrived at the construction site of the Bikou project during the preliminary stages had formed an open field for a 1:50 scale Bikou Hydropower Station model test. From drawings to models, and from models back to the drawings, Cao Chusheng studied the project thoroughly. He usually went to the field and tirelessly investigated the locations and relationships of the buildings with the designers and scientists. He also repetitively calculated and rechecked the scale and the structure of the discharge constructions by comparing the design drawings with the model. At that time, Cao always had a small 10cm slide rule in his pocket, listening to the reports and calculating meticulously as Cao was responsible for both the design and the scientific research. However, as a result of the busy work schedule and the tough living conditions, Cao suffered from migraine. In order, not to interrupt the work, he bought traditional Chinese medicine on the market for self-treatment. Cao, just in his 40s, was already grey-headed.

This Bikou Hydropower Station, built with Cao’s great dedication, is located at 3 kilometers upstream of Bikou town, Wenxian, in Gansu. This was the first large hydropower hub built on the main stream of the Bailong River. After the Wenchuan earthquake on May 12, 2008, Cao continuously paid attention to the effect of the earthquake and the dam safety. In September 23, he re-traced his steps on the familiar land at 82. Despite the rough road, Cao noted the BiKou dam was designed by himself. This half-century old, large-scale rolled earth-rock fill dam was better constructed than Cao Chusheng imagined. After the earthquake, there was basically no trouble. Only forty-four hours after the earthquake, the Bikou hydropower station re-started work and sent electricity to the local disaster area. What’s more, it provided electricity to the Sichuan power grid 58 hours later, offering reliable power for disaster relief. Thus, the hydropower project played a significant role in earthquake relief.

With a serious scientific attitude and precise working style, Cao participated in the assessments and evaluations of Sanmenxia, Liujiaxia, Three Gorges, Ertan, Xiangjia, Xiluodu, Gezhou, Xiaowan, Lijiaxia, Qingtongxia dams and a number of key projects. Cao played an important role in solving key technical issues for these projects.

Ecologically harmonious and the fulfilling the Chinese dream

It was mentioned in the repot of 19th National Congress of the Communist Party of China that building an ecologically sound civilization is vital to sustain the Chinese nation’s development. We must pursue a model of sustainable development featuring increased production, higher living standards, and healthy ecosystems. We must continue the Beautiful China initiative to create good working and living environments for our people and to play our part in ensuring global ecological security. Cao has been insisting on and struggling for the development of water resources exploitation within this whole process since the founding of the People’s Republic of China. Cao’s goal was to establish eco-friendly water conservancy and hydropower projects, at the same time protecting the environment and adhering to sustainable development.

Cao led the construction of Panjiakou Hydro Project in the 1980s, which was China's first large-scale hybrid pumped-storage power station. The so-called pumped-storage power station refers to the use of power to pump water from the lower pond to the upper pond by using the power at low load in the power grid. When the power grid is at its peak load, the water is discharged back to the lower pond to generate electricity. “Although water resources and water energy are renewable, they are valuable”, Cao said. Hydropower and a pumped-storage operation can transform the surplus electric energy when the load of the network is low high value electric energy in the peak period. It is also suitable for Frequency Modulation (FM), Phase Modulation (PM), and stabilizing the frequency and voltage of the power system.

Taking Panjiakou hydropower station as an example, it includes a conventional unit of 150 thousand kilowatts and three reversible stand-alone storage units of 90 thousand kilowatts, for a total installed capacity of 420 thousand kilowatts. This pumped-storage power station system is composed of an upper pond and a lower pond. When the power system is at peak load, four power generation units operate at the same time. The maximum discharge rate is 712 cubic meters per second and the water is temporarily stored in the lower pond. When the system is at low load, the pumping system is operated using the remaining electric power in the network. Water in the lower pond can be pumped back to the upper pond with the maximum pumping flow at 390 cubic meters per second. This routine runs in cycles, can meet the needs of the peak load of the power system and power generation using the same water supply and does not affect each other. Panjiakou Hydro Project has the different functions including water supply, flood control, conventional hydropower and pumped storage, and is a unique way to utilize water resources. To date, it still makes a significant contribution to the Beijing-Tianjin-Hebei region's economic development. The Shisanling Station, Zhang Hewan Station, and Fomo Station are all pumped storage electric power stations which Cao advocated and participated in.

For a long time, Cao was the director of China Pumped-storage Specialized Committee. In 1990, he went to London to attend the International Conference on Pumped-storage. He described the Panjiakou Hydro Project and pointed out that the economic benefits of pumped-storage power stations cannot be undervalued. His views were widely endorsed by the experts at the conference. To his surprise, at that time, the pumped-storage unit was widely used and was known as a conventional unit abroad.

The total amount of water resources in China is 676 million kilowatts, and the developable water resources is 378 million kilowatts. However, in some areas, the water resources and hydropower resources are about to be overdeveloped and exhausted. The construction of new projects will be restricted, which will affect the sustainable development of water resources and hydropower. Cao believes that currently China is in the new and old energy changeover period and the rapid development of thermal power and hydropower has reached its climax. Because of the shortage of coal, water and other resources, it will soon be slowing down each year. New energy sources, such as nuclear energy, wind energy, and solar energy, will gradually replace the former. Pumped-storage, as a supplement of hydropower, can play a special role such as storage and transformation, recycling and regeneration. It is conducive to the harmonious co-existence of new energy and older power systems such as thermal power and hydropower, and to their smooth running.

So far, more than 30 pumped-storage power stations have been built or are under construction in China, and Cao has been involved in most of these stations. These outstanding pumped-storage power stations demonstrate Cao's arduous efforts for the sustainable development of water conservancy and hydropower and the building of a beautiful China.

A scholarly mentor and valuable friend for students, adhering to moral education

From 1987, Cao served as an Adjunct Professor at Tianjin University and also hosted the dissertation presentation for the first foreign Master of Hydraulic Engineering. In 1999, Cao became a Professor of Hydraulic Engineering at the Tianjin University School of Civil Engineering. It has been more than 50 years since he was a teaching assistant at the Shanghai Jiao Tong University and then returning to Tianjin University. He has always been tightly bound to the profession.

In 2004, Zhang Conglin, a freshman of Hydraulic and Hydro-power engineering at the School of Civil Engineering, Tianjin University, was Cao's ‘big fan’. “At that time, I often went to the No.4 Building for study. On the first floor, there were photographs and related deeds of Professor Cao. Every time I saw these materials, I encouraged myself to be a postgraduate student of Cao” he recently recalled. After hard work, Zhang’s dream came true and he became a postgraduate and Ph.D. student of Cao. He still clearly remembered the first time he saw Professor Cao: “With a dark blue Chinese tunic suit, white framed glasses, a pair of ordinary shoes, Professor Cao smiled at me.”

The subject of Zhang's doctoral study was the study of the optimal allocation of capacity of the water-thermal-wind complementary power generation systems. This was a research subject of theoretical and practical significance that had great research value. After determining his study proposal, Cao offered various assistance for Zhang, including a great many relevant books in the field, site inspections to wind energy sites and opportunities of exchanging views with other experts to expand his research ideas.

Although being over 80 years old, Cao visited 16 provinces, autonomous regions, and municipalities with Zhang, such as the Three Gorges project, the South-to-North Water Diversion Project, the Laxiwa Hydropower Station, Jiangsu Longyuan offshore wind farms, the Xinjiang Dabancheng wind farm and the Inner Mongolia Siziwangqi wind farm and solar power plant. Zhang found that Cao was always simply dressed and had not changed his cell phone and suitcase for years. ‘Professor Cao never nitpicked his diet. Comfort and taste were all he needed. He never wasted food. “It's a shame to waste, Professor Cao told me often” Zhang said.

Cao believed that water conservancy and hydropower is a great industry which is related to the economic development of the country and the safety of the people. In addition to the cultivation of postgraduates, he also led the faculty and students of his department to conduct research according to the overall strategy planning of the party and the state. Scientific research work and focusing on the major needs of the country as his fundamental requirement, Cao actively took responsibility for national engineering research and key technology research. While continuously promoting the rapid development of scientific research, he could identify his value and make a great contribution.

Initiating the doctoral program as a first class discipline of Hydraulic Engineering, being awarded the “National Key Laboratory of Hydraulic Engineering Simulation and Safety”, cultivating outstanding young and middle-aged talent who have both ability and integrity, all these improvements made in Hydraulic Engineering were under the leadership of Cao. Lian Jijian, the "Chang Jiang Scholar", Professor of Tianjin University, Cao’s students, all witnessed these developments. ‘Professor Cao encourages young teachers to be innovative and teaches students to be pragmatic. He is not only a scholarly mentor, but also a valuable friend.’

Cao wrote for the "Yellow River" at its 60th anniversary: “I will continue to make new contributions to train high quality talent.” He was always concerned with the growth of the younger generation. On June 2, 2015, Cao’s 90th birthday, he departed from Beijing and returned to the School of Civil Engineering, Tianjin University early in the morning. He took out a draft which has been prepared for 20 days and made a report for the students for an hour. He said: “I have been dedicated to China’s water conservancy construction for 67 years. I hope to share my experience with you that you have to learn from the job and work while learning. Sticking to the practical work and seeking truth.” Cao thought that we should cultivate innovative talent in science and technology, and train them with the necessary skills and comprehensive qualities, including morality, culture, science, business and psychology. In addition, they should be ‘bold to explore, bold in innovation, bold in design ideas, but to be meticulous in structural calculation and detail design".

By reviewing the life experience and encouraging students, Cao was glad to celebrate his birthday. After the seminar, he said: "The University invited me today. I hope I will also celebrate my 100th birthday here."

Editors: Sun Xiaofang, Qin Mian and Ross Colquhoun