I was born in Liuxiayu Village Beijing Yellow River is not the same river as it was 50 years ago. The understanding of it should not be the same as 50 years ago, nor should the management strategies. Discovering the natural hybrid rice by Mr. Longping Yuan lead to a revolutionary of rice, but the discovery of the formation of Beiluohe River Yellow River .
1. Inspiration from the Formation of Beiluohe River
In the 1970’s I participated in the second-round design of the Yellow River , and we investigated the Sanmenxia Reservoir. At the end of the backwater, I discovered the lower reach of Beiluohe River Beihuohe River Weihe River Beiluohe River Yellow River , the conclusion can be drawn that narrow and deep channel is suitable for transporting hyperconcentrated flow. The suitable sediment concentration is not low concentration, and the main reason for sediment deposition along the lower Yellow River is because of the shallow and wide channels. When the majority of the sediment of a river is transported by hyperconcentrated flood, a narrow and deep wandering channel can be developed. The Sediment Research Commission of Chinese Water Resources Society paid great interests in the result of my research, and recommended it to Journal of Hydraulic Research. Finally a journal paper entitled “Sediment Transport Characteristics of Hyperconcentrated Flow and the Formation of Its Bed of Yellow River” published in Volume 8, 1982. In the following days, centered around the impact of hyperconcentrated flow on flood protection, I researched the abnormal phenomena due the strong adjustment of the river bed during the transport process of hyperconcentrated flow on wandering channel, how the “muddy river” is developed, and why flood peak discharge increases along the river. All those research results, can not only answer the questions of flood protection issues in reality, but also consolidate the understanding of the transport characteristics of hyperconcentrated flow.
In order to manage the wandering river channel that is not suitable for sediment transport, in-depth analysis were carried out to study the principle of channel adjustment under different incoming sediment and flow condition, and the phenomena that fine sediment particle is easy to suspend due to the steep slope of the wandering channel. Under such condition, channel adjustment is interrelated and influenced, but the shallow and wide shape is kept. Even with the slope change after siltation, sediment transport capacity doesn’t increase and the equilibrium condition cannot be achieved. On the contrary, the vicious cycles were created, and the evolution characteristics are just like an unstable channel with no drop structure built. Only the narrow and deep river can form a stable wandering channel. These research results were published entitled “Formation of the Wandering Channel of Yellow River and the Transformation Approach” in Journal of Sediment Research in Volume 4, 1989.
2. The Attentions from Academia Prompt the Development of Further Research
The preliminary research results drew attentions from the academia. As early as in 1987, during the Sino-America Symposium on Yellow River Research, member of the Chinese Academy
Based on the reaction from the academia, from 1989 to 1991, Dr Zhaohui Wan led the National Science Foundation funded project entitled “Principles for the Dynamics of Hyperconcentrated Flow and Prospects of Its Application in the Yellow River”, which included the latest research results from Tsinghua University, China Institute of Water Resources and Hydropower and Yellow River Institute of Hydraulic Research. The rheological properties of hyperconcentrated flow, dynamic and sediment transport characteristics, and prospects of its application on the Yellow River . Prefaced by Mme. Zhengying Qian and Mr. Bingwei Huang, members of Chinese Academy Yellow River will never happens today as it was in history. By regulating Xiaolangdi Reservoir, the management of the Yellow River can be achieved through developing a suitable water and sediment condition that sediment is mainly transported by hyperconcentrated flow.
In 1998, during the concluding speeches in the Symposium on Managing the Lower Yellow River , Mme. Zhengying Qian thought the idea of using narrow and deep channel to transport hyperconcentrated flow is a great breakthrough, and hoped it can be reflected in the long term river plans. Under her urges, making full use of the sediment transport characteristics of hyperconcentrated flow to resolve the siltation issue of the lower Yellow River , was listed in the research topics of the Eighth Five Year Plan. This research project was led by me, and it was in collaboration with Yellow River Institute of Hydraulic Research, Yellow River Planning and Design Institute, Tsinghua University
The research results also drew many attentions from the famous scientists. In 1996, 10 members from Chinese Academic of Science or Engineering, namely Kai Yan, Guoren Dou, Binnan Lin, Qianqing Xu, Jiazheng Pan, Bingwei Huang, Dongsheng Liu, Wenxi Huang, Shupeng Chen, Yueding Li, with nine other experts in water resources fields, presented my research results to Premier Mr. Peng Li by Mr. Zhenhuai Yang, former Minister, Ministry of Water Resources. They suggested future collaboration research, and include this in the research topics of the “Ninth Five Year Plan”. However, due to different opinions from other people, it was not successful. But the General Planning Institute, Ministry of Water Resources still provided funding for my research, which made further exploration possible.
3. Formation of the Wandering Reach of the Lower Yellow River and River Training Method
After the Xiaolangdi Reservoir was operated, clear water was released at the early stage. Based on the experiences gained from Sanmenxia Reservoir, clear water scour results the collapses of banks and widens of river, which is not suitable for transporting sediment released by reservoir in channel. During the initial stage of the sediment release from the reservoir based on multi-year sediment regulation, in order to shape the narrow and deep channel, lots of depositions will occur, and the reduction of siltation is not as obvious as water saved for sediment transport. In the long run, if the suitable narrow and deep channel can be formed through river training, not only the siltation can be reduced, but also the flood protection issues of shallow and wide channel can also been resolved. So the research on new river training method for the wandering reach began.
The research on the wandering reach of the lower Yellow River shows, the strong deposition on the main channel results in a lower main channel but a higher floodplain, which keeps the main channel moves frequently, and it is not good for flood protection. After Sanmenxia Reservoir was operated as “store clear water and discharge muddy water”, the effect of small discharge resulting siltation in the channel will decrease. With the control of the river training project, the river channel gradually becomes stable. Although it has positive impact on flood protection, without the fundamental change of incoming flow and sediment for the wandering reach, it also controls the location of sediment deposition, and changes the evolutionary principles that the natural river will shift to balance the elevation differences between the main channel and the floodplain, and results in the increase of the main channel becomes faster than the increase of the floodplain. This is the main reason for the “Secondary Suspended River
The major training task for wandering reach is to stable the main channel, and develop the flood discharge and sediment transport corridor. The idea of using “minor curves” to train the wide reach thinks, since the flow line always follows a curvature path, and river training should be based on this rule to stabilize the channel. This idea is based on the training experiences gained from the transition reach downstream of Gaocun. However, the successful example of Gaocun is due to the channel geometry, a narrow and deep channel, not due to the horizontal curvature. To develop a narrow and deep channel through two-bank training is based on the stochastic characteristics of the channel evolution, the adjustment for the channel bed is developing towards the vicious circle. The “minor curve” training method cannot control the river regime to develop a narrow and deep channel. Narrow the channels can only reduce losses due to the inundation on the floodplain, while two-bank training can develop an efficient flood discharge and sediment transport corridor, and control the bed elevation not to increase.
4． Unsteady Features of Flood and Understanding the Principle of “Scour during Rising of a Flood, and Deposit during Falling of a Flood”
Based on multi-year’s research on the dynamics of sediments in the Yellow River , it should be noted that the mechanics behind the phenomena need to be figured out. Since only by understanding the process and the reason of this phenomenon, the knowledge of the Yellow River can really be obtained. Take the “Deposit on the floodplain while sour the main channel” as an example, after a big flood, there are significant depositions on the floodplain, while there are strong scours in the main channel. From the appearance, they have close relationship, but after the sour process in the channel, it is found that the scour always happens during the rising of a flood. During the falling of a flood, no matter the high or low concentration, there is always deposition on the main channel, even when there are 10 time differences in the channel slopes. From this perspective, the hypothesis of channel scours due to the return of the clear overtopping flow is not true. But how could this happen? It cannot be explained based on the outdated theory of steady flow and single-valued relationship of sediment carrying capacity. From the reality of the Yellow River , we should first learn the theory that narrow and deep channel has the characteristics of “the more sediment input, the more sediment output” (Please refer to Journal of Sediment Research, No.2, 1994). The former director of Institute of Sediment Research, Mr. Lianzhen Ding read this paper and wrote me a letter, and suggested it be published in the Internal Journal of Sediment Research (in English) he edited. With the help of Translation into English, this paper was finally published in No.2, 1995 of this journal. Based on the theory, correct understanding can be obtained with the analysis of the unsteady feature of the flood, as well as the relationship between the change of the forces on the channel bed, and the scour and deposition of the channel. It took us almost 10 years to research on this complex problem, before the research results were published in Journal of Hydraulics, No.6, 2005.
The unsteady feature of the sediment transport by flood, and the understanding of the theory of “Scour during rising of a flood while siltation during falling of a flood”, opens the new path of harnessing the lower reach of the Yellow River . We finally understand that why the rivers with either high or low sediment concentrations, steep or mild slopes, will always be scoured during rising of a flood, and silt during the falling of a flood. With the progress of the understanding this feature, the principles of flood discharge of narrow and deep channels, no-defined relationships between silt on the floodplain while scour on the main channel, long distance sediment transport by flood, regulation of sediment release from reservoir have been greatly advanced. Based on the new understanding, we proposed “non-river bed aggredations” should be set as the strategic aim of harnessing the lower Yellow River .
5. The Difficulties of Applying the Scientific Concept of Development
At the early stage when a new academic theory emerges, there are always strong objections from the traditional opinions, which is perfectly normal for the development of science. Mr. Zhaozhong Ding once said, the development of science always follows a rule that the majority of people will agree with minority of people. When new ideas emerge, it is common to have disputes, and it is also normal that most people will object to them. It is a difficult thing to change the traditional opinions.
Faced with a complex river like the Yellow River , it is natural to have debates in understandings. The debates between different academic theories are the motives for the development of science. We wrote letters to related leaders many times and provided our suggestions. For example, we wrote more than ten suggestion letters to Planning and Strategy Research Center, General Institute of Water Resources Planning, entitled “How to Harness the Lower Yellow River Channel” to be included in the Water Resources Analysis and Research Report in China. However, the research results have not drawn sufficient attentions from the administrative agencies.
For the ideas of harnessing the Yellow River in 21st Century, Ministry of Water Resources proposed overall management objectives for the Yellow River : “no embankment breaching, no river course running dry, no pollution over standard and no river bed rising”. Among them, the most difficult one will be “no river bed rising”. Former Minister of Ministry of Water Resources, Mr. Shucheng Wang paid great attentions to our research results. In 2001 when Yellow River Conservancy Commission analyzed the new idea of harnessing the Yellow River in the 21st century, I was appointed as the member of the writing group by luck. The functions of narrow and deep channel in harnessing the lower reach have already been included in the preliminary report, but not in the final formal report of New Management Ideas of 21st Century. In 2005, the agreement on how to manage the lower reach after the operation of Xiaolangdi Reservoir has been reached between Prof Ye’an Zhao, me and Commissioner Mr. Guoying Li. After the meeting, the minutes were documented on developing the main channel suitable for flood discharge and sediment transport, so that the highest efficiency of sediment transport can be realized. But no follow-up happened. In 2008, I reported this issue to Vise Minister Mr. Yong Jiao who’s in charge of planning. He agreed to prompt this idea by select a wide reach, and carry out experiments on two-bank training as a pilot case study. He has talked with the directors from Yellow River Conservancy Commission, but nothing happened afterwards, which made us dwell a lot.
Member of Chinese Academy
6. The Prospects of Harnessing the Lower Yellow River Are Broad, But There Is A Long Way to Go with Huge Responsibilities.
The famous expert on sediment research, Prof. Ning Qian (1922-1986) initialized new research areas of studying hyperconcentrated flow. The famous expert on managing rivers, Prof. Zongdai Fang (1911-1991) first proposed to harness the lower Yellow River by using hyperconcentrated flow. As the student of them, based on the practices gained from the reality closely, I concluded the experiences of their successes and failures. By tracking the changes of flow and sediment in the Yellow River , based on the sediment transport characteristics of hyperconcentrated flow, I proposed a whole new method to overcome the sediment problems of the lower Yellow River , and develop and use the water resources properly. I also sincerely hope that the decision should be made promptly to apply the research on hyperconcentrated flow resulting from generations of scholars in the real engineering practices, which can contribute to the management and development of the Yellow River .
The rivers in North China are turning into dry rivers gradually, with very few floods occurred. The Yellow River watershed is also located in semi-arid region. With the construction of reservoirs, soil and water conservation project, and the development of irrigation, the field observed discharges of the flood also reduced significantly.
Due the combined operations of Longyangxia Reservoir and Liujiaxia Reservoir, and the increase demands from industrial and agricultural uses, the incoming flow can reduce as much as 10 billion m3 during the flood season in a wet year. With the reduction of flow peaks, the bed shaping function has been weakened, which results in more and more conflicts between less water and more sediment. The trend for significantly reduced possibilities of flood occurrence is irreversible. But the flow and sediment condition entering the low reach can be regulated through Xiaolangdi Reservoir on a multi-year basis, and it can be optimized by using sediment release by flood. This also creates condition for making full use of the powerful flood discharge and sediment transport capacities of the narrow and deep channel.
Operation rules, known as “Store clear water and release muddy water” of Sanmenxia Reservoir avoid the sediment deposition on the main channel with small discharges during non-flood season. This operation rules was implemented since 1973, by using the reservoir capacity to regulation sediment downstream of Tongguan, although there were occasions that sediment was released with small discharges, the siltation is still reduced for the channel of the lower Yellow River . River channel upstream of Huayuankou is basically non-aggradated. Xiaolangdi Reservoir is also operated on a multi-year basis, based on the theory that more sediment will be transported during flood seasons. The water resources of Yellow River can be fully used, and better conditions are created for training the wandering reaches. The solid scientific support of the comprehensive sediment management methods like “block, discharge, regulate, release and dredge”, while “regulate” is the key component, is also provided for developing the narrow and deep channel of the lower reach. Sediment release due to the empty of reservoir, and the collapse of sediment deposition which can be reused for a long time, create better incoming flow and sediment condition to ensure the long term non-aggradations of the lower Yellow River channel.
After the operation of Xiaolangdi Reservoir, due to the optimal operation rules, river channels in Henan Shandong Provinces Henan Shandong
Through the multi-year sediment regulations of Xiaolangdi Reservoir, the sediment is regulated to be transported by flood. By using this method, the goal of non-rising of the main channel can be achieved or even decrease. The reason is when the hyperconcentrated flow occurs; the main channel is always scoured. During the initial stage of Xiaolangdi Reservoir when clear water is released, after the sediment deposition volume is all filled up, the multi-year sediment regulation rule will be implemented. The sediment is regulated to be released during flood. By using both methods, most of the channel bed will not be raised.
The increase of flow capacity of the main channel will reduce the opportunity of the flood overtopping onto the floodplain, which can make a harmony relationship between the people living in the floodplain with the nature. 1.8 million people living in the floodplain can be totally free of worries, and 3.59 million mu of farmland can be fully utilized. This is the objective request from people-oriented, scientific development point of view for managing the lower Yellow River .
After the operation of Sanmenxia Reservoir, the regulation rules already been in effect which achieve non-aggradations of river bed upstream of Huayuankou (The floodplain of Meng County Wen County
Scientific development view has already become the major national policy. The innovation of technology should be strengthened, which can turn fruits of science and technology to realistic prolificacy. But until now, the administrative agencies still don’t recognize the huge flood discharge and sediment transport capacity of narrow and deep channel, and they don’t pay much attention to the feasibility of its application in harnessing the Yellow River .
Members of Chinese Academy Yellow River : “Scientifically regulating flow and sediment can better shape the downstream channel, and more sediment that enters into lower reach can be transported to sea.” The existence of production dykes already made the lower Yellow River channel as a “narrow channel”. The most pressing matter of the present, should be including the two-bank training strategy which aims at developing a stable, narrow and deep channel, in the long term plans of harnessing the lower Yellow River, and promoting this strategy vigorously. By doing this, we can prove the science and technology are primary productive forces, and it can have an irreplaceable effect on managing and developing the Yellow River . The dreams from various people who care about harnessing this river can be realized soon.
7. My Declaration
The publication of this book is the public reply for various people who wish the research results from hyperconcentrated flow can be applied on managing the Yellow River . The author of this book has devoted unremitting efforts during his lifetime in this research, and all the related issues have been resolved. However, I cannot contend the change in the reality of this society!
1. The strong objections from the traditional researchers of the Yellow River
In regards to our river management strategy, people who are not favorable of it has similar characteristics, that is, they objected not from the technical point of view, like whether or not the channel has the huge capacity of flood discharge and sediment transport? They based their objections emotionally, like the argument “When Pangu created this world, the river is a wide river, so there is no need to change it to a narrow one today”. When the leaders of Ministry of Water Resources wanted to carry out the experiment using my idea on the lower Yellow River, someone said things like, “We cannot allow this experiment, since we do not want to give him chance.”, “Even if we were wrong, we won’t change our plan.”, “Are we all wrong?”, Since the wide river plan can attract more funding. Traditional researchers do not want to recognize the sediment transport potentials of the channels in the lower Yellow River . If they do accept this idea, the whole river training plans need to be changed. One person who is objected to my idea once announced publicly, “If what you said is all true, 5000 years history of harnessing the lower Yellow River will be rewritten. If the huge flood discharge and sediment transport characteristics of the narrow and deep channel is recognized, the famous saying of “less water but more sediment in the lower Yellow River will not be true anymore”, which will weaken the theoretical foundations of traditional management strategy!
2. There are no long term objectives for planning the Yellow River
Under the thinking that “nothing has been understood of the Yellow River ”, there are no best solutions, and “it’s difficult to manage this river” becomes a very good excuse. In 2000, Yellow River Conservancy Commission proposed a 500 billion RMB budget on important issues of the Yellow River . Members of Chinese Academy Yellow River reaches to 900 billion RMB, but there is still no clear management objective. In fact, it appears more like attracting funding. Following Mr. Jiazheng Pan’s suggestions, Chapter 20 was added in the planning document, but there is no change for the previous 19 chapters, which cannot be used to achieve the goals prescribed in the 20th chapter. There are contradictories on regulating water and sediment in the middle reach, but harnessing lower Yellow River as a wide river and storing sediment on the floodplain. The economic society is the outside condition for why the issue above occurs.
3. Drawbacks of the current design and research
From the realistic benefits, deign institutes only concern about if they could win big investment for a project. Regardless of the design method, the payment is based on certain percentage of the overall investment. The design institutes only worries about if they could be paid a full salary to their employee including benefits, and they are busy with launching projects. For many years, it is the reason that nobody is interested in discussing this issue seriously. Research and design institutes are only responsible for the owner of the project, but lack the spirits of being responsible for people. Even there is something wrong, they don’t investigate into the details. It won’t be easy for us to change the money-oriented society today.
4. The application of the research results is extremely difficult.
Everyone wants to contribute to harnessing the Yellow River , so they will feel uncomfortable about new ideas and achievements proposed by other people. For instance, the non-project based river managers thought our research is a monstrous crime. Even after the acceptance from the reviewers, my research paper was rejected by the acting editor based on the following reason, “The practices of managing rivers in 20th century have demonstrated that to radically remove the river related hazard, is not economic, unnecessary, and even impossible. Trying to pursue the objective of radically remove the river related hazard is even harmful.” Our research is fully based on measured data collected along Yellow River , so we do want our opponents to show their realistic proofs.
For such a complicated river like the Yellow River , it is natural to have different opinions. The debate between different opinions will motive the development of science. We should organize an active academic discussion. However currently there are few discussions in journals. Journal of Hydraulic Research is the technical journal published by Chinese Association of Hydraulic Engineers, and it should become the academic media which allows a hundred schools of thought to strive. Once I told the editor-in-chief, Mr. Bingxin Chen, “Whoever has different opinions about my paper, please let him published in this journal, and we welcome such suggestions. If your paper got some issues, and other person is willing to help you revise it, we should be appreciated for their assistance.”
During the symposium on “Wide River Narrow River
5. The hope for the solution still exists.
Based on the research findings of my paper, only the respected senior level of researchers can express their attitude. However, suggestions given by those experts do not draw enough attentions from the river management administrations. No solutions can be offered to solve the above issues in our society yet.
It is true that Mr. Guanhua Xu once said, “when faced with debates, opportunity and risk, waiting is never the best solution. The government should take full responsibilities and make the decision with audacity. It all depends on whether the leader is willing to have their determination, their capability and their guts to make those decisions. For the current merchandise prevailed society, the decisions from the upper administrations appear to be more important.
Member of Chinese Academy
Serious research on sediment transport by using the characteristics of hyperconcentrated flow to reduce the siltation on the lower Yellow River channel have been conducted for forty years. A whole new plan of harnessing the Yellow River has been proposed. The administrative leaders should pay attention to the result from this research. I sincerely wish the early application of my research on the Yellow River .
The spirit is willing, but the flesh is weak. I cannot turn the expectations from eight perishing members of Chinese Academy Chinese Academy
By Pu Qi
August, 2010.
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