Preface II of My Book on Yellow River Research and Management Strategy by Mr. Jiazheng Pan, Former Minister, Ministry of Water Resources, China

I was asked by Mr. Qi Pu for his a new published collaborators’ research monograph to write this Preface. The book contains their long-term research results of the sediment problems in the Yellow River. I did it late because I do not feel to have the floor on the book due to that I am little known about the Yellow River circumstance, and in a layman especially on the sediment dynamics and the problem of sediment transport. After considering for a long time, I hold a pen and write the following words, this is a preamble, rather some feelings. I write out it for authors and experts to be referred and commented on.

The Yellow River is the China’s mother river , and the Yellow River basin is the cradle of Chinese civilization. Beyond the memory of men and throughout the history, floods and drought disasters in the Yellow River basin are very frequent and serious, especially due to that the sediment concentration in the river is huge, the downstream river bed silts up unceasingly, the river becomes the suspended river higher than its banks, and the river bank bursts durring large floods, causing the vast area to be flooded, even river diversion maks disaster-ridden, therefore the Yellow River is also called China's misery, and is rivers which in the world is most difficult to be governed with. Since 1949, although the harnesing of the Yellow River has made great achievements, but did not solve the problem of sediment ultimately, the river bed is continuously siltted up, forming a second-order-suspended river. After completion of the Xiaolangdi Multipurpose Dam project, very good results have been achieved via the reservoir regulation of water and sediment dischage to scour the sediment in the reservoir and its lower river channels. But how to optimize the operation of water and sediment discharge and make the most favorable effect of washing sediment deposition, it relates to the harnesing orientation of the lower Yellow River and still has all sorts of disputes.

The key research project by the authors to work with perseverance for 30 years is emphases on how to use the hyperconcentration flood flow larger than 3000m³/s to transport the sediment into the sea, enable the sediment in downstream river channels basically to achieve the equilibrium of sediment erosion and deporsition. This possibility exists according to the authors’ comparative analysis of measured data and their summarization of the river sediment transport law, the premise is to create a stable downstream of narrow-deep river channel, and optimize a mode of water-sediment regulation in Xiaolangdi Reservoir to release an artificial flood, carry out overyear regulation of sediment, change incoming water and sediment composition of the lower river channels, which enable to suit the longe distance flowing condition of hyperconcentration flow, thereby the flood can be fully used to discharge the sediment. If those could be achieved, the major part of sediment would be transported entering the sea, to create a balanced condition of sediment erosion and deposition in the lower river channels. From this understanding, the authors propose the different opinion to the current harnessing theory and practice of the Yellow River. 

If the author's scenario can be achieved, of course, it is very good: the lower Yellow River channels can no longer be silted up, the Xiaolangdi  Reservoir can bring into play in long term (instead of trapping), and also the floodplain can be released due to that it do not have to rely on both sides of the floodplain used for silting. Because of the complexity of problems and influencing severity, the author's research results and the corresponding harnesing programmes exist in different point of views, and this is understandable. Science progress constantly in discussions and debates, the truth is radicated under the continuous research, testing and in practice. However, no matter what scenario is adopted, it is consistent that a stable and deep river channel would be wanted to be created in the lower River reaches, and is always right that the orientation of to deep study it and give fully play to its sedment transport potential. The book published will facilitate debates. I hope the people of all circles concerned the Yellow River harnesing, especially the colleague who research sediment transport law of the Yellow River can discuss the viewpoints and conclusions of the book, and also the authors being calm and even-tempered to deal with various discussions and oppugned opinons, deepening and improving their work, and to reach a consensus, for the realization of the Yellow River's ultimate goal to make more contributions.

In addition, for the deeping research on harnessing of the lower Yellow River reaches, I thought that also has several major problems to be worth further discussing:

1. In history, flood disasters in the lower Yellow River reaches were very serious, but large floods here have not happened in recent decades due to various reasons, even in the flood seasons the larger flood peaks are also not to be formed. How the defence standard for the lower Yellow River flood from now on is determined in reason? Can the defence flood discharge be cut down largely? How to deal with the above-norm flood when meets? These problems must have clear conclusions approved by the State, as the objectives and warranty of the Yellow River harnessing.

2. After a variety of harnessing measures (including the author's programme) to be adopted, how to secure a reasonable and reliable estimate of the annual sediment deposition quantity in the lower river channels in the near future? When can anticipatorily the sediment erosion and deposition equilibrium be completely reached? Meantime what are the gross sediment deposit amount and siltation shape in downstream river course? What is the impact of the flood control? How is the reliability of that the authors believe that their harnessing programme to be adopted can maintain the river channel to be not deposited? How much room should be left? Whether should the sediment deposition and flood discharge function of the floodplain be reserved?

3. The Yellow River emptys itself into the Bohai Sea that is a shallow sea, sediment discharged out of the river mouth can not automatically entering the deep sea area, and it appears as the continuous extension of the Delta and smoothout of the riverbed slope, as a consequence those have a gradual impact of sediment transport into the sea. How to recognize in macroscopic way and specific solution to this problem seems to be doing more in-depth research (see Chapter 16 of the book).

4. The harnessing orientation of the lower Yellow River relates the 1,800,000 farmer's development direction who depend upon more than 3,000,000 Chinese acres of floodplain by both banks for making a living. this is currently the most real problems on the lower Yellow River harnessing. If the author's suggestion was accepted, farmers housing on the floodpains within both banks would enjoy a good and prosperous life gradually. If according to the current river harnessing planning to put into practice, a early planning would be needed to do that how to scientifically and rationally use the floodplains in both banks, and whether or not the resident on the floodplain to be requalification or change the position. In the river harnessing opinion can not be temporarily in the consistent situation, to shape a stable and deep river channel in the downstream river reaches is a scenario of compromising all sorts of assumption and advantageous  exploration step by step. Meanwhile, the operation mode for water and sediment regulation of the Xiaolangdi Reservoir may be explored and optimized, to closely monitor the sediment deposition reduction of the lower river channels, to see that whether the river bed sedimentation can be controlled or not, and whether the river channels’ flood dicharging capacity can be increased unceasingly or not, then to decide what river harnessing scheme can be adopted, it seems a positive and safe way.

Certainly, these questions do not belong to the research scope of this book, I just like to take this opportunity to put forward for leaderships and observant and conscientious persons to be taken into account.

Above is my preface for authors and readers to refer to and comment.

                               

Pan Jiazheng 

                                                                                                                                            on June 17, 2010 

Preface I of My Book on Yellow River Research and Management Strategy by Mr. Shucheng Wang, Former Minister, Ministry of Water Resources, China

The Yellow River is the most challenging river to manage in China, possibly even in the world. Generations of water resources engineers painstakingly applied unremitting effort in exploring the research, development and protection of this river. As early as in 1955, a comprehensive plan on Controlling the Flood and Developing the Water Resources of the Yellow River was passed in the Second Session of the First National People’s Congress. After a half century’s research and engineering practices, great achievements attracted worldwide attentions have been made.

However, it is still an extremely complex task to manage and protect the Yellow River. Sediment problems of the Yellow River have not been completely resolved. In the lower Yellow River, issues such as aggraded river bed due to siltation, secondary suspended river, transversal/diagonal river and floodplain inundation are still great threats. Flood protection remains a concern with potentially severe consequences.

Managing the complex lower reach is interrelated with managing the entire upper and middle reaches of this river. Flooding of the lower Yellow River is primarily caused by continuous siltation, which results in rising of the channel bed. A crucial element of sustainability is how to realize “no channel bed rising” in the lower reach. This condition can be achieved through water and sediment regulation employing combined operations of reservoirs in the middle reach, and regulations of the channels in the lower reach. This strategy will increase the sediment transport capacities by flood, and solve many problems such as secondary suspended  river, and sedimentation on the floodplain and bayou.

In recent years, Committee of the Chinese Communist Party, 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”. Inspired by these objectives, many theoretical and practical research results have been obtained by numerous water resource engineers. The author of this book is one of them. For many years, he has focused on how to manage the Yellow River, especially the sediment problems of the lower reach. This book emphasizes on the author’s own view and in-depth analysis on the mechanisms of flood discharges and sediment transport capacity of the channels in the Lower Yellow River, the evolution and the reformation of the braided reach of the Lower Yellow River, water and sediment regulation based on combined operations of reservoirs, and construction of the high efficient flood discharge and sediment transport channel.  The publication of this book should be celebrated, since it opens new path in understanding the sediment problems of the lower Yellow River. I sincerely wish more and more engineers would devote themselves to the research of managing and developing the Yellow River, and contribute to the ambitious goal of “no river bed rising”.

Shucheng Wang,

Former Minister, Ministry of Water Resources, China.

(Thanks for the revision of the translation from Mr. Daniel O'Leary, P.E. of NMP Engineering Consultants, Inc., Baltimore, Maryland, http://www.nmpengineering.com)

Yellow River's Research and Management Strategy

Forward of My Book "Sediment Transport Potentials of the Lower Yellow River Channel and Development of the High Efficient Flood Discharge and Sediment Transport Channel". 

Google Book Link.

The Yellow River is the cradle of Chinese nationalities, and it is famous for its abundant sediment in the world. Due to the severe soil losses from the middle reach, a great amount of sediment is washed away by flood, and deposits in the channel of the lower reach. This process has resulted in a “suspended river” and frequent levee breaches, which brought grave disasters to people living in this region.

As early as in 1955, a comprehensive plan on Controlling the Flood and Developing the Water Resources of the Yellow River was passed in the 2^nd Session of the First National People’s Congress. After half century’s research and engineering development, great achievements attracting worldwide attentions have been made. However, sediment problems of Yellow River have not been completely resolved. In the lower Yellow River, issues such as aggraded river bed due to siltation, secondary suspended river, transversal/diagonal river and floodplain inundation are still great threats. Flood protection remains a concern with potentially severe consequences. Seeking a strategy that can radically eliminate flood hazards becomes a high priority task.

Siltation is the main reason for flood hazard in the lower Yellow River. In the early days of the foundation of P.R. China, based on the planning principles of “store water and trap sediment by reaches”, a comprehensive plan on the Yellow River was proposed. This goal was trying to keep all the sediment in the upper and middle reaches, which could thus alleviate the sediment deposition and flood threats in the lower reach. As the preliminary results in reality showed, the effect of Water and Soil Conservation Project of Losses Plateau and management of sediment-laden tributaries to reduce sediment was not so obvious. Sanmenxia Reservoir was forced to be reconstructed twice, and its function was altered from “store water and trap sediment” to “detent flood and release sediment”. In the book published in 1987 entitled “My River Management Practices”, the famous river training expert Mr. Huayun Wang pointed out during his conclusions of the experiences gained on managing the Yellow River, “In the past, it was always thought that managing the Yellow River should focus on issues related with the upper and middle reaches. Once those issues are resolved, so are the issues related with lower reach. From the failures and frustrations, I have learned that to manage the Yellow River, we should not solely focus on upper and middle reaches, but rather on all reaches as a long and painstaking task, also on the lower reach (page 200).” In the preface of this book, he also pointed out “The thinking of water and sediment regulation is still in the developing stage, and the experiences gained are not completed yet. But in my opinion, this approach is more scientific, and meets the realistic situation better. In the future development, great breakthroughs can be achieved from this aspect.

There are more than 10 major water conservancy projects on the main stem of the Yellow River. The total flood control capacities of Longyangxia Reservoir, Liujiaxia Reservoir, Sanmenxia Reservoir and Xiaolangdi Reservoir reach 15.62 billion m³. On the major tributaries, there are also many big reservoirs, such as Luhun Reservoir on Yihe River,  and Guxian Reservoir on Luhe River, with flood control capacity of 0.677 billion m³ and 0.698 billion m³, respectively. Once in 1,000 year flood at Huayuankou Hydrologic Station has reduced the peak discharges from 42,300 m³/s to 22,500 m³/s. Once in 100 year flood has reduced from 29,200 m³/s to 15,700 m³/s. If the 1958 flood of 22,300 m³/s happened today, the peak discharge would be reduced to 9,620 m³/s. After the 1982 flood of 15,300 m³/s, for almost 30 years, peak discharges at Huayuankou have never exceeded 8,100 m³/s, which means the flood is under fully control. The key issue of managing the floodplains of the lower Yellow River is how to achieve the non-aggregation of the river bed.

Due to the combined operations of Longyangxia Reservoir and Liujiaxia Reservoir, and the increased industrial and agricultural water demand, the amount of water flowing into the lower Yellow River has been reduced significantly. The peak discharges have also been reduced, which weakens the bed-shaping function of a flood, and the conflicts between less water and more sediment are more and more severe. The planned function of Sanmenxia Reservoir, “store clear water and release muddy water” now faces more and more challenges, and the limitation is more and more obvious.  There are new situations and tasks emerging for the flood protection of the lower Yellow River.

In the past, people always concluded the main reason for the severe depositions on the lower Yellow River as “less water and more sediment” in general. Compared with other major rivers in the world, the average annual sediment of 1.6 billion ton with the discharge of only 50 billion m³ should really be called “less water and more sediment”. However, does a heavily sediment-laden river always lead to a “bad” river? The answer is “no”. As an example of the major tributaries like Weihe River and Beiluohe River in the middle Yellow River reach, sediment-laden rivers do not necessarily lead to a severely deposited meandering river.

As the research on hyperconcentrated flow initialized by Prof Ning Qian demonstrates, the reason for the huge sediment carrying capacities by hyperconcentrated flow is due to the existence of fine particles which change the characteristics of the fluid. With the dramatic increase of the flow viscosity, and the decrease of fall velocity for coarse particles, even the coarse particles are easier to be transported in the hyperconcentrated flow. The resistance force of the river bed to flow does not increase accordingly, which can still be calculated by Manning’s equation. Under the conditions of same slope and water depth as the clear water flow, the velocity of hyperconcentrated flow will not be decreased. Therefore, sediment transport by using the characteristics of hyperconcentrated flow in Yellow River is really an economic and ideal technical measure.

Mme Zhengying Qian, member of the Chinese Academy of Engineering, has paid great expectations on the research of the hyperconcentrated flow and its application on the Yellow River. She has emphasized the importance of related research many times during her speeches, and wished its applications on managing the Yellow River.

As early as in 1988, she pointed out, “Concerning the river training issues, I feel that there is a great breakthrough in understanding the lower Yellow River channel.   Besides the levees can be strengthened by siltation inside and outside of the banks, researchers from the Yellow River Institute of Hydraulic Research proposed sediment transport by using hyperconcentrated flow and management of medium and small discharges to reduce siltation, which deserves in-depth studies and analysis. If there is a breakthrough in research, the amount of water needed for sediment transport, and the sediment carrying capacity of the channel will likely to change dramatically. The amount of water needed for sediment transport, from some reference I have read, ranges from 10 m³/ton to 30 m³/ton. That means, for transporting every 100 million tons of sediment to sea, some people think 3 billion m³ of water is needed, while some other people think only 1 billion m³ is needed. Now the planned water quantity for sediment transport is 20-24 billion m³, and 8-10 billion m³ during non-flood season. We should really pay attention to different opinions about water needed for sediment transport, and the sediment carrying capacity of the channel. I hope in the future plan, there are evaluative comments about those opinions, and the future work direction should be proposed.”

On April 15, 1992, during the working conference with the Yellow River Conservancy Commission, she pointed out “Yellow River is the most challenging river to manage in China, possibly even in the world. During the past years, we achieved great accomplishments with the efforts from generations of researchers and engineers. For future plans, we need to keep up the good spirits, and try to combine the diligent work on current issues with early explorations based on reality and innovative thinking. That is from my personal experience. Since every year there is a realistic flood protection task, we need to accomplish this task first with great performance. However, only finishing the flood protection task, but no future explorations based on reality and innovative thinking, is not enough. That is to say, both tasks are important to us, and we need to combine them closely to manage the Yellow River.

In 1993, when she wrote the preface for my book entitled “The Dynamic Principles of Hyperconcentrated Flow in the Yellow River and Its Applications”, she said “The Yellow River is the most sediment-laden river in the world, and it is the most difficult river to manage. With the construction of big reservoirs like Longyangxia Reservoir and Liujiaxia Reservoir in the upper river, the amount of water flowing into the main stem has been reduced significantly. The conflicts between less water and more sediment become more and more prominent. The Yellow River flows through the most arid region like Northwest China and North China, which needs urgent compensation by more water sources. How to make full use of the limited water resources of the river, and try to furthest satisfy water demands, becomes the most important issue in developing and managing the Yellow River.

This book emphasizes on illustrating the fundamental research on the rheological properties, dynamics and sediment transport characteristics of the hyperconcentrated flow. Based on the field surveyed data, the principle of sediment transport theory was studied, and the conclusion was the narrow and deep channel has significant sediment transport capacity. Make full use of the channel to transport sediment to sea, reduce the deposition on the river bed, save water needed for sediment transport, can be very worthy research topics to be explored.

Initialized by Prof. Ning Qian in the 1950’s, it has been several decades for the basic research on hyperconcentrated flow in the Yellow River. The research topics gradually evolve from pure theories to engineering practices. Active researches are now focusing on how to regulate the water and sediment more scientifically with the current and future projects on the Yellow River. I hope both the old and young colleagues in the water resources engineering field can cooperate to achieve greater accomplishments in developing the theories and practices of hyperconcentrated flow.”

The Yellow River is the most sediment-laden river in the world, and it is perhaps the most difficult river to be managed. However, it is also a promising river to be harnessed. After several generations’ research and engineering practice in our country, there is a major breakthrough in the knowledge and understanding on sediment transport of the Yellow River, i.e. the high flood discharge and sediment transport capacity of the narrow and deep channels can be used to transport sediment to sea. Ministry of Water Resources proposed the overall management objectives for the Yellow River in 21^st century, “no embankment breaching, no river course running dry, no pollution over standard, and no river bed rising”. The most difficult objective is to achieve “no river bed rising”. For the new situations emerged since October 1999, after the Xiaolangdi Reservoir began operations for trapping sediment and creating a flood to scour downstream channel, the Yellow River Conservancy Commission also proposed detailed technical measures for managing the downstream channel, “stabilize the main channel, regulate the water and sediment, widen the river and strengthen the levees, and compensate the flood inundation”. Among the five major sediment managing measures, “trap, discharge, regulate, release and dredge”, “regulate” is the most important component. Only when the sediment is regulated to be transported during flood season, the transport characteristics of the narrow and deep channel called “more sediment coming in, and more sediment will be transported” can be fully used to transport more sediment to sea. Only when the sediment concentration in the flow is regulated to a certain high level, the water required for sediment transport can be reduced. As conclusion, constructing a straight narrow channel with certain sediment discharge capacities can form an efficient flood discharge and sediment transport corridor in lower Yellow River. By using the multi-year sediment regulation operation of Xiaolangdi Reservoir and sediment discharge capacity of the narrow and deep channel, the deposition on the main channel can be controlled, and the non-aggradations of the river bed in the lower Yellow River can be achieved.

Located just upstream of the lower reach of the Yellow River, Xiaolangdi Reservoir is the last big valley-type reservoir with large regulation capacity. After its operation, better conditions can be provided for improving the flood protection, silt reduction and water supply for residents living in the vicinity. Thus, how to make full use of its advantages to regulate water and sediment more wisely, transform the channel shape from shallow and wide to narrow and deep, make full use of the sediment carrying capacities of the channel, and save the water needed for sediment transport, have great strategic significances for managing the middle and lower reaches of the Yellow River. There are two major criteria to judge the pros and cons of the water and sediment regulation rules of a reservoir: 1) how much sediment can be regulated to be transported during flood season; 2) how much water can be utilized through the reservoir regulation.

Based on the understanding of the flood discharge and sediment transport principles of the narrow and deep channel of the Yellow River, this book proposes the future direction of managing the meandering reaches. Stabilizing the main channel and developing a narrow channel can secure the flood protection, and the sediment transport capacity of the channel can thus be increased. As a result, the sediment transport capacity during flood season can be fully used to transport more sediment to sea. From this perspective, developing a narrow and deep channel with certain flood discharge and sediment transport capacities should be the major objectives for managing the meandering reaches. The increased of flow capacity of the main channel will reduce the opportunity of overtopping flood on the floodplain, which will develop a harmony relationship between the people living in the floodplain with the nature. The 1.8 million people living in the floodplain can be totally free of worries, and 3.59 million mu of farmland can be fully used. From the people-oriented, scientific development point of view, the management method introduced in this book is the objective requirement for managing the lower Yellow River. Only when the channel is regulated to narrow, deep, straight, smooth and stable with high efficient flood and sediment discharge capacity, the objectives of the non-aggregation of the river bed can be achieved. The problems of water resources shortage, secondary suspended river and its floodplain, sediment of the bayou, etc. can thus be resolved properly. What will appear in front of us is a deep main channel with floodplain at high elevations. The strategic objectives of non channel bed rising can then be accomplished.

Since October, 1999, the Xiaolangdi Reservoir began operations for trapping sediment, creating flood to scour downstream channel, and regulating medium and small discharges to reduce the siltation in the channel downstream of Aishan.  The total amount of scoured sediment in the downstream channel has reached 1.3 billion m³. Channels upstream of Gaocun and downstream of Aishan have all been scoured. Between Huayuankou and Jiahetan, for the discharge around 2000 m³/s, the water depth reduced about 1.8 m. This value also reduced 1 m in the channel downstream of Aishan. Bankfull discharge at Gaocun station has reached 5,300 m³/s or more. With the effect from the production dikes, average flood will not overtop the levee. But the reach upstream of Jiahetan is still shallow and wide, with an average width of 2,000 m to 3,000 m, which needs two-bank regulation urgently.

After the sand fills the sediment-regulation volume of Xiaolangdi Reservoir, regulate the sediment on a multi-year basis, release the sediment at the right moment, transport most sediment during flood season, can all contribute to the non-rising of the river bed, or even scoured river bed. Since every time when hyperconcentrated flood occurs, the main channel is always scoured, and the sediment transport characteristics can be described as “scour during the rising of flood and deposition during the falling of the flood”. Release clear water from Xiaolangdi Reservoir at the initial stage, regulate sediment on a multi-year basis after the sediment fills the sediment-regulation volume, release the sediment at the right moment, can be successfully combined to achieve the non-aggradations of the river bed.

The traditional opinions believe the extended siltation at the bayou is the main reason for aggradations of the channel in the lower reach. The only solution is to reduce sediment source. The impact of the optimal incoming flow and sediment condition on scour and deposition in the channel of the bayou has greater effect than that of sediment deposition and extension in the bayou on the upstream channel. The sediment transport potential could be fully utilized to transport more sediment to sea during flood season, and bed-shaping function of flood and sediment transport capacity can also be increased. The impact on the upstream channel can be adjusted by varying the river width to reach the new equilibrium of sediment transport.

Sediment transport by flood will create density current at bayou, and the sediment will be deposited in a larger area. By using the wave dynamics from the ocean along the coastline, sediment can be transported to open sea. The flow path in bayou will not extend any more, and the negative impact on channels in the upper reach can be mitigated.

Proposed by Senior Engineer Mr. Zegang Li, a flood and sediment diversion project at bayou should be constructed. By making full use of the wave dynamics of the ocean and storage capacity of the sediment in the sea area, and the better incoming flow and sediment condition henceforth, impact of the extended siltation at the bayou on the channel of the lower reach can be minimized, and non-aggradations of the river bed will be achieved.

The publication of this book clarifies the critical issues of managing the channel of the lower reach, and it will continue to contribute to the process of eliminating the flood-hazard and developing the water resources. With the implementation of bayou management and regulations of the lower reach channel, multi-year sediment regulations and constructing the high efficient sediment transport corridor are proposed by the author of this book. The flood hazard will not occur again in the future as it was in history, and people will enjoy their peaceful life forever.

The main reason that the understandings of managing the Yellow River can not be reconciled at present can be concluded as the following. Traditional river managers do not want to recognize the flood discharge and sediment transport potentials of the lower Yellow River channel. Everyone saying “less water with more sediment” is the crucial issue of this river. But if we do admit the findings in this book, the major management issues of the Yellow River will change. The understandings of this river and the regulation strategies will also have significant improvements. The process of how I researched the Yellow River will be introduced in the postscript of this book.