Current Situations of Water Resources of the Yellow River

Living Lab: Yellow River

(1) Water consumption exceeds the bearing capacity of the Yellow River, and the water shortage is very severe.

The mean runoff is 58 billion m³. With the development of economy and society, water consumption will increase constantly. Water consumption in life and production rises from 12 billion m³ in the 1950s to 30.7 billion m³ now (other regions out of the basin consume 10.6 billion m³). This causes a serious problem of zero-flow in the lower stream. In the past 27 years from 1972 to 1998, zero-flow occurred in 21years with a total duration of 1051 days. Every year from 1990 to 1998, zero-flow occurred and the lasted time was longer and longer, so was the length of the river reach. In 1997, the situation was the most serious. Lijin cross-section, nearest to the estuary had zero-flow for 226 days in a year, the zero-flow section extended upward even to Kaifeng City in Henan Province. Frequent zero-flow and less water flowing into the sea cause the aggravation of the contradiction between supply and demand and the deterioration of ecological environment and water-pollution. These extremely threaten swamps in the estuary and the ecological diversity, increase the channel deposit, weaken the discharge capacity and burden the flood-control.

After the unified dispatch of water in the trunk in 1999, zero-flow has been lessened. But, because of water shortage in this zone and the weak supervision system in the basin, an authoritative, effective and harmonious supervision system has not been formed, and the management is still weak. There are neither essential laws or policies nor economic means for unified regulation. So water shortage and zero-flow can not be settled thoroughly.

(2) With the development of economy and society, the gap between supply and demand of water is even more serious.

It is estimated that in 2010, considering water saving, the total water consumption in the basin and the neighboring areas will increase to 52 billion m³. Considering sand transport in the down stream in flood season and the minimum ecological flow in other seasons, the Yellow River Basin can provide a maximum water volume of 48 billion m³ in normal years (including 11 billion m³ ground water), with a gap of 4 billion m³. In moderately dry year, water shortage will reach 10 billion m³. Water shortage has been a basic restricting factor of the sustainable development of economy and society in the Yellow River Basin and the pertinent areas.

The loss of water and soil and the deterioration of water environment not yet controlled effectively.

(1) Water and soil losses have not been controlled effectively.

There are some conspicuous problems in the harnessing of water and soil losses:

Firstly, for a long time, the investment is extremely deficient with slow progress of harnessing. The existing standards are fairly low without corollary equipment, and the survival rate of trees and grass is very low.

Secondly, the harnessing in some areas which have more sand and coarse sand, is extremely lagging and the gully works and dam works are few. The Loess Plateau is a chief sand-production area covering 7.86 thousand square kilometer, where the economy is very backward and the ecology is weak. Due to the lack of gully and dam works, the measures of intercepting and reducing sand are not so effective.

Thirdly, the prevention, supervision and management are not effective. In some areas, the phenomenon of harnessing and destroying at the same time is very common. During the mining of coal and nonferrous metal in the bordering areas of Shanxi, Shaanxi and Inner Mongolia, and Henan, Shaanxi and Shanxi, the relationship between economy and ecology has been ignored, which deteriorates the weak ecology itself. The area of forest belt in Ziwu Mountain and Liupan Mountain is decreasing year by year. With the increase of human demands from the nature, new factors leading to water and soil losses arise, and the pressure on ecology is heavier and heavier.

(2) Water pollution is more serious.

The industry in the basin is usually of low investment, high consumption and heavy pollution. There are so many enterprises which consume more water and produce more contaminations. Especially, from the mid-1980s to the early 1990s, paper-making, chemical plant, tan and other heavy-pollution factories developed quickly. So the pollution sources and its discharge capacity have greatly increased; at the same time the treatment of pollutant was not sound for the lack of effective supervision. Then plenty of raw effluent that could not reach the standards was drained into the river. In the early 1990s the effluent load reached 4.2 billion m³, which is twice as much as that of the early 1980s. Water quality deteriorated sharply. The Official Gazette of Chinese Environment Condition by the National Environmental Protection Bureau in 1997 showed that, compared with other rivers in China, the polluted length of the Yellow River ranked the second. Compared with the water-quality of 1985, in 2000 the length with the water-quality standards of Ⅳ, Ⅴor inferior to Ⅴ increased by 30.4%. The deterioration of water quality not only does harm to life and health of the people directly, but also aggravates water shortage greatly.

It is estimated that the pollution discharge in the whole basin will exceed 6.5 billion m³ in 2010. At the same time the pollution caused by fertilizer will spread further. If effective measures can not be taken in time, water quality in the trunk stream and tributary nearby the large or middle cities will possibly exceed the water-quality standard of Ⅴ. This will threaten the safety of water supply.

(III) Main cognitions

In the long-time of harnessing and developing of the Yellow River, through the continuous exploration of “practice-cognition-practice again”, the following cognition about the particularity and regularity of the Yellow River is deepened gradually.

1. The Yellow River has less water but more sand and is very difficult to harness. The urgency and importance of the harnessing and developing must be realized. Its protracted nature and complexity must also be completely considered.

2. All factors must be taken into consideration as a unity which can influence and restrain each other. The factors include natural conditions, ecological environment, economy and society. Great emphasis should be put on their correlation for calamity elimination and benefit generation.

3. Considering the correlation of water consumption for ecology, industry and agriculture, water-saving measures must be practiced. To realize the sustainable utilization of water resources, the optimized distribution, conservation and saving must be intensified.

4. Sediment problems are still the key. Equal attention must be paid to sand control and flood control. Water and soil conservation must be looked on as a radical measure to the harnessing.

5. To solve the problems of the Yellow River, both engineering measures and non-engineering measures, particularly the up-to-date techniques must be emphasized.

6. Guided by the theory of socialist market economy, the harnessing and developing of the Yellow River must esteem the laws of nature and economy.

Flood Control of the Yellow River

A Journey Down the Yellow River

Flood-control measures include flood-control engineering in the downstream, flood-control reservoir in the trunk and tributary, channel improvement in the upstream and midstream, stabilizing reservoirs in dangerous places, flood-control for key cities and non-engineering measures, etc. The key is the flood-control engineering in the downstream.

1.       Flood-control engineering in the downstream

Flood-control construction in the downstream focuses on stabilizing all the dykes, accelerating the channel improvement, constructing the detention area in the Dongping Lake and shoals, and regulating the estuary.

(1) The stabilization of dykes

Long-time practices show that it is a long-term strategic step for flood control to stabilize dykes in the downstream by “warping, digging, silting and deposition to form a relative underground river”.

Build standardized dykes. According to the requirement of flood control in the downstream, the dykes with less than 12m width on the top, and the 1109.3-kilometer-long dykes whose cross-section can not satisfy the  anti-seepage requirement must be widened. According to the standard of the third grade highway, the dyke tops must be hardened to the width of 6m. In order to cover the danger that occurs on the back land of the river and guarantee that there is no seepage and landslide in the back dyke, based on the requirement of constructing ‘a relative underground river’, we will stabilize 1239.6 km dykes, including strengthening 1180.4km dyke by warping (50km by digging channel), with a width of 100m and the equal height with the designed flood level. Wave prevention forest inside the dykes and ecological forest in the silt-back top must be planted. Cutoff wall of a 59.2km length must be stabilized, 135 dangerous works must be modified and stabilized. 91 guard dams of the dykes along which there is frequent flood must be built, the existing 146 guard dams must be heightened and stabilized. The dykes in the downstream will be a flood-control line, a traffic line in emergency and an ecological landscape line.

(2) Channel improvement

There is a great change of scouring and silting in the wide river section above Gaocun in the downstream. The river regime wanders without regularity. It is very difficult to harness. The application of Xiaolangdi Reservoir has controlled the silting of this river section for a certain period of time. It creates a favorable condition for controlling the Yellow River. This river section must be paid more attention.

Based on the practical experience of channel improvement in the lower channel in recent years and the existing projects, it is planned to build and rebuild 53 controlling and diversion works with a length of 93.1 kilometers in the section above Gaocun; and 45 controlling and diversion works with a length of 41 kilometers in the section below Gaocun. To reduce dangers, it is necessary to increase the quantity of using the sausage-mattress dam and the concrete-post dam besides the traditional willow-box stone structures. And at the same time, we should heighten and strengthen 177 controlling and diversion works which can’t reach the required standard.

(3)  Estuary improvement

The estuary improvement is an important part of the flood-control engineering in the downstream of the Yellow River. Considering the present condition that the height of dykes and the strength of some cross-sections are not adequate to the flood-control requirements, left-dike of 43.7 kilometers long should be heightened and widened; 36.5-kilometer-long top should be hardened. 77.5 kilometer-long anti-wave forest should be planted along the river. Meanwhile, 4 dangerous works and 7 control-diversion works should be continuously built and 9 control-diversion works should be heightened and strengthened.

(4)  Flood control engineering in the downstream of the Qinhe river

Part of the dikes along the downstream of the Qinhe River below Wulongkou are not stable enough and there exist many hidden dangers. It is planned to widen 44.3 kilometer left levee and stabilize 19.5 kilometer dyke by warping; to strengthen 42 kilometers banquette on the back of the right dike. Pressure grouting and crown hardening should be done, and 13 gates be transformed, 17 dangerous works be built or expanded.

(5)  Dongpinghu Flood Detetion District

Although the Xiaolangdi reservoir has been set up, Dongpinghu detention project is still the critical flood control engineering, which is related to the safety of the narrow part of the river in Shandong Province, it is the focal part of future construction. So it is planned to strengthen 77.8 kilometer dikes by using cut-off walls; to transform the secondary lake dike -- Baliwan Gate Station; to dredge the culverts; to height and strengthen the Daqinghe River embankment; and to reinforce and alter the control and diversion works and dangerous works.

To ensure the safety of the residents in the Dongping Lake’s detention district, it is planned to adopt two ways--building village pedestal and temporary withdrawal to avoid the flood on the spot. In the new lake area, we will adopt the temporary withdrawal and build 100km retreating road; in the old lake area, we will build village pedestal to avoid flood on the spot, the pedestal is 391.6 million square meters.

(6) The safety construction in the shoal

To ensure the safety of the shoal along the downstream, it is planned to organize migration of the residents living within 1 km from the bank. The number of the migration is 467 thousand. According to the building standard of the migrants town, an area of 7.946 million square meter on the habilitation is needed, and village pedestal of 76.44 millions square meters are needed for the safety of 1.274 million people to avoid the flood. In the down-draught area in Fengqiu County, we will build 200km retreating road to facilitate the temporary withdrawal of 228 thousand residents.

2. Flood control reservoir in the trunk stream and tributary

(1) Utilize the combining force of the present reservoirs, and make full use of their sediment reduction and flood control. 

In recent terms, while strengthening the forecast of flood, runoff, and sediment, it is necessary to comply a yearly plan about water and sand regulation, conduct the real-time operation carefully, carry out the flood control and sediment reduction in the flood period to optimize the relationship of water and sand, enhance the efficiency of sediment transport in the downstream, and alleviate the sedimentation accumulated in the downstream.

(2) Further improve the system of flood control and sediment reduction engineering system

For the improvement of the system of flood control and sediment reduction, it is planned to finish building the Hekou reservoir by 2010 and to accelerate the preparatory work of Guxian multi-purpose project to start the construction as early as possible.

Guxian multi-purpose project is located in the downstream of Shanxi and Shaanxi Gorge on the north trunk of the Yellow River. It can basically control the flood from Hekouzhen to Longmen and 59 percent of sediment in the Yellow River. The total storage capacity is 15.3 billion cubic meters, the usable storage is 4.65 billion cubic meters. Guxian reservoir can intercept sand and reduce 7.7 billion tons of sedimentation in the downstream channel. When it is combined with the Xiaolangdi reservoir, it can control silting and riverbed rising significantly for a long period of time, meanwhile, it can reduce nearly 5.4 billion tons of sedimentation in the channel from Yumenkou to Tongguan, and lower the elevation of Tonguan, create favorable conditions for the improvement of the channel from Yumen to Tongguan and the downstream of the Weihe River. The application of reservoir to flood control can lower the detention level and sedimentation of Sanmenxia reservoir in big flood, and reduce the rate of flood downdraft into the Wehei River.

Hekoucun Reservoir is located in the downstream mouth of the last gorge of the Qinhe River. The total storage capacity is 3.3 billion cubic meters. After completion, flood peak discharge at Xiaodong Station of the Qinhe River can be reduced from 9500 cubic meters per second to 4000; flood control return period can be raised from 20 years to 200 years, and the threat on the downstream of the Qinhe River can be largely mitigated. At the same time, the flood peak discharge can be further cut down in the downstream of the Yellow River.

3.Channel training in the upper and middle reaches  

(1) Section between Ninxia and Inner Mongolia

The section between Ninxia and Inner Mongolia is plain, and it is 869.5 kilometers long. The height of most dikes is not enough, channel training works are insufficient, the mainstream swings frequently, and the trans-dike buildings can not meet the standards, which is a threat to flood control. Since 1986, the dike has been breached 4 times in ice flood, which greatly affected the economic and social development in the region.

To solve the problem of flood control and ice prevention in this section, it is necessary to heighten 670.6 kilometers long dike, build 17.4 kilometers long dike and 6 anti-danger works, and expand 13 anti-danger works. The trans-dike projects will be merged and transformed, meanwhile, the gullies’ inlets of the Yellow River should be regulated. 18 control and diversion works ought to be established, 31 control and diversion works should be expanded, 1,9000 residents who live in the floodplain below Shizuishan should migrate to outside.

(2) Section from Yumenkou to Tongguan

The length of this section is about 130 kilometers. It’s an alluvial river. Scouring and silting are especially violent there. The shore usually collapses, which often triggers the lift-irrigated stations on both banks to lack water. The building of 15 control and diversion works and bank protection works is in great need, 19 works should be heightened and strengthened.

(3) Section from Tongguan to Sanmenxia dam and the downstream of the Weihe River

This section is about 110 kilometers long. It belongs to Sanmenxia reservoir area. To effectively control the shore-collapse, it is necessary to build and rebuild 8 channel regulation works, 26 anti-erosion and anti-wave works, and heighten and strengthen 3 works.

To resolve the problem of flood control in the downstream of the Weihe River, 98.3 kilometers long main dikes should be heightened, 15.7 kilometers long dykes should be strengthened by warping, 143.1 kilometers long dike should be grouted by cone drilling, and 98.3 kilometers long crown should be hardened. Besides, 11 channel regulation works should be rebuilt, and 15 kilometers long dikes on Nanshan tributary should be stabilized.

In the area below 335 m elevation in the downstream of the Weihe River, 23,000 people return from outside. According to the flood-control principles, protection-dike should be heightened and strengthened according to requirements. 197,000 m2 refuge platform should be constructed to avoid the flood, and 37 kilometers long retreat road should be built.

In order not to let the elevation of Tongguan continuously goes up, it is planned to dredge the section close to Tongguan based on the rational utilization of the Sanmenxia reservoir. If Guxian multipurpose project can be put into practice, Tongguan elevation will be further lowered and controlled in the future.

4. Dangerous reservoir reinforcement and the flood control in major cities

(1) Dangerous reservoir reinforcement

At present, there are still 83 large and medium-sized reservoirs running with problems along the Yellow River (including 12 large ones and 71 medium-size ones). To guarantee the safety of the life and property in the downstream, it is imperative to accomplish the reinforcement of dangerous reservoirs.

(2) Flood control in major cities

At present, there are 8 provincial capital cities and 5 district cities in the Yellow River Basin. They are Xining, Lanzhou, Yinchuan, Huhehaote, Taiyua, Zhengzhou, Ji’nan, Baotou, Kaifen, Shizuishan and Luoyang. The flood control in these cities still can’t meet the standards. For the safety of these cities, it is essential to reinforce the flood control constructions in the above 13 cities and to make it reach the standards soon. We should pay attention to the flood avoidance while constructing cities. It is forbidden to occupy the poundage area and flood channel. The requirement of river flood control should be taken into consideration comprehensively when developing various fundamental facilities. Special emphasis should be laid on storm drainage facilities in downtown area.

5. Non-engineering flood control measures

To increase the accuracy of hydrologic prediction and observation, it is planned to enhance the construction of hydrologic measurement facilities and equipment, and hydrologic prediction service system. Emphasis should be put on upgrading the equipment of the hydrologic stations on the trunk and the control stations at the tributary inlets, such as Tongguan Station, Huayuankou Station and Gaocun Station. A flood warning system covering the section from Xiaolangdi to Huayankou and a weather observation radar detection system covering the section from Hekou to Sanmenxia should be established.

Flood control teleconference system, decision-making and command system and flood control information net need to be set up to enhance the ability of flood control decision-making. In order to reduce the investment for dealing with emergency, shorten the time of handling emergency, and quickly control the danger, 15 “24-hour, prompt, flexible” mobile emergency-handling teams should be established, and the current 20 teams ought to be upgraded.

A Reasonable Approach to Manage the Floodplain of the Lower Yellow River

Book Review on Flood Discharge and Sediment Transport of the Yellow River (by Pu Qi)

Recently, as an important book of Henan Province sponsored by the publishing fund of Managing the Yellow River from the Yellow River Conservancy Commission, China, Flood Discharge and Sediment Transport Positional of the Lower Yellow River and Development of an Efficient Flood Discharge Channel, was officially published by Yellow River Conservancy Press. Former Minister of the Ministry of Water Resources, China, Mr. Wang Shucheng, former Deputy Director of Chinese Academy of Engineering, Mr. Pan Jiazheng, and former Director of Yellow River Conservancy Commission, Mr. Li Guoying, wrote prefaces for this book, respectively.

The Yellow River, the second largest river in China, is well known as a highly sediment-laden river. The average annual sediment inflow entering the Lower Yellow River is 1.6 billion tons. Every year, there are around 400 million tons of sediment deposited on the lower reach of the Yellow River, which results in raising of river bed with a speed of 10 cm per year. Unbalanced relationship between water and sediment with less water but more sediment is the outstanding issue of the Yellow River. The main direction of managing the Yellow River should focus on developing a harmony relationship between water and sediment. With the implementation of Water and Soil Conservation Project of the Loss Plateau, sediment that comes into Yellow River can be reduced significantly. At the same time, how to make full use of the sediment transport characteristics of the hyperconcentrated flood, and the potential sediment transport capacity of the natural channel to transport as much sediment as possible to sea, becomes the key technical issue when dealing with the hyperconcentrated flood.

There are four parts, seventeen chapters in total in this book. It demonstrates the research results of one decade from the 1980’s to the operations of Xiaolangdi Reservoir, as the followings:

1.        Part One (five chapters) introduces flood discharge/sediment transport characteristics and potentials of the narrow and deep channel. With the analysis on the mechanism and the condition of a phenomenon called “the more sediment comes in, the more sediment will be transported.”,  it also explains the dynamics and evolution rules of the hyperconcentrated flood, reasons for abrupt increase of flood peaks, friction characteristics of hyperconcentrated flow, influences of the change in sediment concentration and energy slope on sediment transport, erosion during rising and deposition during falling of a flood event in an alluvial river, and reasons for the powerful flood discharge and sediment transport capacity of narrow and deep channel.

2.        Part Two (two chapters) illustrates the principles of variation in the meandering reaches, and conditions of the river pattern transformation, and it provides methods to regulate the meandering reaches.

3.        Part Three (four chapters) explains the key technologies of flow and sediment regulation by the reservoir, application rules and control conditions of multi-year sediment regulations,   mechanical properties of reservoir sediment, possibilities that the hyperconcentrated flood can be created during reservoir emptying, flow and sediment regulation by combined reservoir operations, results of the reduced sediment deposition after multi-year sediment regulations, and the amount of water required for sediment transport that can be saved.

4.        Part Four (four chapters) explains the outstanding issues in harnessing meandering reaches, causes for the secondary suspended river, analysis on whether the production dykes should be demolished or not, comparisons of the pros and cons between various river training plans, and the necessities of two-bank training. It also provides theories and technologies of how to construct an efficient channel for flood discharge and sediment transport.

5.        Chapter 16 analyzes the favorable condition of transporting sediment of Yellow River to the ocean by floods.

6.        Chapter 17 illustrates the bright prospects of managing the lower Yellow River channel.

This book summaries the author’s research results for years, and it illustrates in greater details the fundamental characteristics of the hyperconcentrated flood, and the analysis on comparing the field data collected along the main stem and tributaries. From the results of this study, the channel with narrow and deep shape was found suitable for transporting hyperconcentrated flow. The necessity of developing the hyperconcentrated flood was also proposed. With the research on the operation mode of Xiaolangdi Reservoir, the authors proposed “sediment should be regulated on a multi-year basis, and it should be released at the right time”, and they proved the feasibility of creating hyperconcentrated flood by combined reservoir operations. Sediment in Yellow River comes from the floods, so let the floods carry it away is the best solution. If we can make full use of sediment transport by flood, even when Xiaolangdi Reservoir cannot be used for flushing sediment by clear water, the downstream channel can still be scoured. With the research on regulations of meandering reaches in the lower Yellow River, the authors proposed the two-bank training strategy to stabilize the main channel, and they studied on developing an efficient flood discharge and sediment transport channel.

This book analyzed the new problems and significant changes of the lower Yellow River channel after the operations of Xiaolangdi reservoir for a decade. Since October, 1999, when Xiaolangdi Reservoir began operations for storing sediment, creating flood to scour downstream channel, the total amount of sediment that was scoured in the downstream channel has reached 1.3 billion m³. The water surface elevation in the channel upstream of Gaocun has decreased 2 m for the same discharge. Bankfull discharge at Gaocun has reached 5,300 m³/s or more. The water depth also reduced 1 m in the channel downstream of Aishan. But the river reach upstream of Jiahetan is still shallow and wide, which needs two-bank regulation urgently to develop a narrow and deep channel. The operations of this reservoir is also creating beneficial conditions for the multi-year sediment regulations, sediment transport into the ocean by flood, and the non-rising of the river bed elevation. If the above regulation measures can be successful, then the outstanding issues of the Yellow River, the so-called “unbalanced relationship between water and sediment with less water but more sediment” can be totally overcome.

The Yellow River is the most sediment-laden and the most difficult river to manage in the world, yet there is great hope to harness it. The publication of this book clearly points out the most crucial points for managing the downstream Yellow River channel. If the proposed multi-year sediment regulations and an efficient flood discharge and sediment transport channel in the lower reach can be achieved, the complete removal of the flood hazards, the development of the water resources and the control of the downstream channel will all be accomplished. The appendix of this book contains seven important documents, including the proposal by ten Chinese Academy of Science and Engineering members, with Mr. Pan Jiazheng, and etc. in 1996.

The preface by Mr. Wang Shucheng emphasized the necessary technical measures to achieve the non-river bed rising of the lower Yellow River. The preface by Mr. Pan Jiazheng emphasized the four major problems that need to be overcome for managing the lower Yellow River channel. The preface by Mr. Li Guoying underlined the important research results obtained by the author throughout years, and at the same time he indicated that some views and opinions in this book are still in debate at the theoretical and practical level of studying the Yellow River issues. In the postscripts of this book, the author introduced how the understandings of the Yellow River were developed throughout the years, and he pointed out the reason that the management measures can not be applied for the Yellow River is, traditional river managers do not want to recognize the powerful sediment carrying capacities of the lower Yellow River in reality. If they admit this, the famous saying of “less water but more sediment” will not hold any more! This will definitely shake the theoretical foundations of the traditional river management strategies on the Yellow River!

My Retrospect and Prospect for Managing the Yellow River

I was born in Liuxiayu Village, North of Changxindian in the City of Beijing, 1942. In 1963 I began working at the Sediment Research Division, China Institute of Water Resources and Hydropower, when I first exposed to the sediment issues of the rivers. It has been 47 years since that time. In retrospect, I deeply feel that 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 channel didn’t promote the revolution of the management of Yellow River.

1. Inspiration from the Formation of Beiluohe River’s Channel

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 flowing into the reservoir has a narrow, deep and stable channel, just like a man-made wandering canal, which gave me great impression. When I asked this question, Prof Ning Qian meditated for a while, and then said “high sediment concentrations”. In the following years, I analyzed the research results from previous studies, and found the incoming flow and sediment, the channel evolutionary characteristics of Beihuohe River and Weihe River. There were frequent floods of Beiluohe River with sediment concentration around 700-900 kg/m3. The narrow and deep channel was shaped by the flood, and great amount of sediment can be transported over several hundred kilometers reach with strong scour on the main channel. The sediment transport characteristics of Weihe and Beiluohe’s channel have greater similarity with that of the hyperconcentrated flow in the canals and pipelines. For the muddy flow in pipelines, just like the sediment size distribution of hyperconcentrated flow with particles smaller than 0.08 mm in diameters, can all be treated as gravity media. As long as the resistance force can be overcome, the particle can be transported without considering the sediment carrying capacities. Through the analysis of field-observed hyperconcentrated flow data collected from different reaches along the main stem and major tributaries of the 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 of Science, Mr. Bingwei Huang (1913-2000) pointed out “Among various strategies, using the properties of hyperconcentrated flow to transport sediment to sea and eliminate the sediment deposition on the channel bed of lower reach, might be an effective technical measure.” “If we were sure that hyperconcentrated flow cannot be used for sediment transport now, I do want to know the reason to reject it.”

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 of Science and Engineering respectively, the results from this project were published, with their sincere hope on the research of the hyperconcentrated flow. The history of flood hazard of lower 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 and China Institute of Water Resources and Hydropower. Through three years of hard work, this research project was successfully completed. The research results were published officially in a book entitled “Research on the Change of Water and Sediment in the Yellow River and the Measures to Reduce the Siltation in the Lower Reach” by Yellow River Water Resources Publishing Co. Ltd. This book was the first one to propose new flood protection function of Xiaolangdi Reservoir, which is sediment discharge by flood instead of eliminating hyperconcentrated flow. This operational method of this reservoir is also changed from the traditional “store the clear water during non-flood season, and discharge muddy water during flood season” to “regulate sediment on a multi-year basis, and discharge it at the right time.” It clearly indicated that during dry years the sediment should not be discharged to downstream, and the reservoir should be operated by the maximum benefit mode. The calculation results also showed, the benefit of using this method will be greatly increased and the water demand for sediment transport can also be reduced by 2/3, with an average annual demand of only 6 billion m3. The sediment discharge will be arranged only during the flood season in wet year when Xiaolangdi Reservoir cannot be regulated. 

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”, and the situation becomes worse with the contribution from the production dykes, creating new threats for flood protection. Shallow and wide channels are also the main obstacles for transporting sediment to sea by using channel itself.

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 of Science, Mr. Jiazheng Pan once said, “Any new idea, as long as it’s named new, means it lacks practical experiences, and there is certain uncertainty involved. The impact of whether a water conservancy project is success is huge. How to secure the project while promoting new technologies becomes a controversial issue. As a vivid example, it’s like who’s going to be the first person to eat crab. In my opinion, there are two methods to resolve this. The first point is to emphasize both “Caution” and “Active” as the basic rules, and either one of them can be neglected. “Caution” means to keep a clear mind, never do anything that has no solid foundation, or there is uncertainty involved. Everything should be experimented and based on the results obtained; the conclusion and decision can thus be made. Especially for the curial projects or part, we can never be careless. “Active” means from our minds, we should believe the innovation and development should be the right way on earth. We should warmly welcome new things with faithful hearts, and conduct in-depth analysis, and create everything we can to ensure their mature and feasibility. We should have the courage to be the first in the world, and not the passive wait, “wait until someone else try it first”. The second point, from the strategy, we should emphasize “seek truth from facts, and treat differently”. (Taken from Pan’s book entitled “The Philosophies in the Constructions of Water Conservancy Projects”.)

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 and Shandong Provinces have all been scoured. In Henan, the scour depth is about 1.8 meters. In Shandong, the sour depth is 1 meter. The total amount of scoured sediment reached 1.3 billion tons.

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 and Wen County has already been turned into residential areas for reservoir resettlement. The multi-year sediment regulations of Xiaolangdi Reservoir, and sediment release by using flood can achieve the non-deposition of channel upstream of Gaocun, or even Aishan. The major issues of the secondary suspended river and management of floodplain can be resolved. The management plan proposed by Mme. Zhengying Qian of  using a narrow channel can also be realized reach by reach.

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 of Science, Mr. Jiazheng Pan once pointed out in his suggestions on managing the 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 of Engineering, Mme Zhengying Qian, commented on this budget, “the thinking is not clear, and there is no operability.” This time the budget of planning of 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 or Narrow River”, in front of hundreds of audiences, I have also declared that “on my personal website, there are numerous technical papers of my research.  I sincerely wish the young generations to find flaws in any fundamental theory in these papers. I have a monthly salary of several thousand RMB after retirement, which can be used as the bonus. However, eight months passé,d and no one can claim the bonus.

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 of Science, Mr. Bingwei Huang wrote the following in the preface of my book published in 1993. “I am 80 years old, and I don’t have many days left in my life. But I still hope before I die, I will witness the water and soil conservation and hyperconcentrated flow research can really contribute to eliminate river hazards radically, and people can enjoy the peaceful life forever.  Flood hazards will not happen today as it was in the history. People of Central China will have happy lives ever since, and our ancestors who worked diligently on managing the Yellow River throughout years will be pleased to rest in peace. I am a senior citizen who’s close to seventy years old, and will soon leave the earth to go to heaven. Now I have the same feeling as Mr. Huang.

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 of Science and Chinese Academy of Engineering, as well as other senior scientists who care about harnessing the river, into practices. I really hope in the future, people with lofty ideas will fulfill my unaccomplished historical task.

By Pu Qi

August, 2010.