An analysis of the limitations of the thought of governing the Yellow River in past dynasties

There have been five great leaps in understanding in the past dynasties. At the same time, accompanied by five major breakthroughs in the thought of governing the Yellow River, China's primitive thought of governing the Yellow River in the early ancient times, Pu Su's thought of governing the Yellow River in the middle ancient times of China, China's preliminary thought of governing the Yellow River in the late ancient times, and modern comprehensive thought of governing the Yellow River and contemporary China's highly comprehensive thought of governing the Yellow River were formed.

China's thought of harnessing the Yellow River in ancient times was generally confined to the lower reaches of the Yellow River (later extended to the middle reaches), and his main idea was to "discharge flood and sediment" into the sea. The control measures adopted are also extremely simple, that is, "blocking, dredging and dredging" (dredging rivers and building dikes). Among them, in the early and middle period of ancient times, the idea of "diversion (distribution)" was the main idea. In the early period of ancient times, people did not see the harm of sediment, but only considered "simply" discharging floods into the sea. The difference is that in the middle of ancient times, Zhang Rong opposed a diversion. He first recognized the sand damage of the Yellow River and put forward the rough qualitative relationship between sediment deposition and velocity for the first time. However, just like Jia Rang's combination of "treatment (drainage and sediment discharge)-use (irrigation and sediment discharge)", it did not attract people's attention at that time.

Table 13. 1 Brief analysis and periodic comments on the thoughts of harnessing the Yellow River in previous dynasties

In the late ancient times, when it was clearly recognized that the harm of the Yellow River was "sediment" and the need of "both flood discharge and sediment discharge" was taken into account, the idea of "combining water (i.e. collecting water)" represented by Pan Jixun and Wan Gong gradually took the dominant position, replacing diversion as the dominant idea of governing the Yellow River in this period. However, as far as the effect of its implementation is concerned, whether it is the idea of "diversion" or "confluence", it only reduces the harm of flood and sandstorm in a certain time, in a certain range and to a certain extent, and has received temporary results. Diverters only know that the potential is small, but they don't know that long-term diversion will cause serious siltation in the river below the diversion mouth. They only pay attention to "flood", but they don't see the "sediment" characteristics of the Yellow River, and they don't realize the inherent law that "the sediment transport capacity of rivers is proportional to the flow". Therefore, "weak water" and weak potential will inevitably lead to adverse consequences of sediment deposition. The riverbed is rising year by year, and the reciprocating change of the river course is out of control. However, the confluence only sees "great combination" and "great potential for sand attack", hoping that the river channel will become deeper and deeper and the flood discharge capacity will become stronger and stronger. However, due to the lack of water and more sediment in the Yellow River, the water and sediment are extremely uncoordinated and the flow changes greatly. Therefore, the result of "confluence and water collection" can only be a bunch of water in the end, but it can't attack (wash) sand well. As far as the whole river course is concerned, it is still inevitable that the riverbed will continue to accumulate and rise on the whole. The main reason for these situations is that we only saw the flood and didn't realize the sediment; Or they are aware of sediment, but they lack understanding of the changing law of riverbed erosion and deposition.

Compared with ancient times, the understanding of the essential laws of the Yellow River in modern times has made a major breakthrough, and the idea of governing the Yellow River has made great progress. Horizontally, the scope of river regulation is not limited to the downstream, but extended to the middle and upper reaches of the Yellow River. It is the first time to put forward the idea of comprehensive development of river regulation that pays equal attention to the upper, middle and lower reaches, flood control, shipping, irrigation and hydropower, instead of the simple idea of "separation and integration" and "discharging flood and sand into the sea" in the past. Vertically, it is clearly pointed out that "the harm of the Yellow River lies in sediment", the harm characteristics and causes of the Yellow River, and a more detailed soil and water conservation control method of "combining biological measures with engineering measures" is given for the first time. But as far as the problem of "sand control" is concerned, except for the idea of "storing water to stop sand" in the middle reaches, the idea of "sand control" in the lower reaches has not progressed, and it has not yet broken away from the ancient idea of "attacking sand with water" and "flooding the beach" At the same time, the research on the law of water and sediment transport and the micro-mechanism of soil and water conservation has just started, and many things are still poorly understood. There is only some theoretical research, but there is still a lack of necessary practice to test the Yellow River regulation.

On the basis of summing up and absorbing the thoughts and experiences of predecessors, the contemporary Yellow River regulation has carried out large-scale practical activities for the first time, and revised and improved the Yellow River regulation thoughts of past dynasties in practice. Horizontally, the scope of understanding has been extended to the whole Yellow River basin area of this river and its tributaries; Vertically, the scientific work of harnessing the Yellow River has been strengthened, such as water and sediment transport, soil and water conservation and river stability experimental research. On the issue of "sand control", the management ideas of "combination of blocking and discharging, silting on both sides of the strait" and "combination of blocking and discharging" are clearly put forward, which are clearer in the thinking of "governance" and closer to the reality of the Yellow River. To a certain extent, the rapid development of soil erosion and desertification in the middle reaches of the Yangtze River has been curbed, and the goal of flood prevention in a certain period of time has been achieved.

Generally speaking, with the development of science and technology and social productive forces, people's practice and understanding of managing the Yellow River are gradually deepened, and the idea of managing the Yellow River is constantly improved and tends to be perfect.

However, when we further examine the practical effect of the contemporary thought of harnessing the Yellow River, we find that its achievements are beyond doubt, but the key problem of harnessing the Yellow River has not been well solved, and even many problems are just a point and far from being solved. For more than 60 years, "going to the dam" has not stopped, and the average sediment discharge for many years has not decreased significantly; The "discharge" has not been discharged, and the downstream channel is still growing year by year; "Cross-strait siltation" has limited effect and is not a long-term solution. In recent years, Xiaolangdi Reservoir has been used for water and sediment regulation. In the long run, it may be difficult to form a dynamic scouring and silting situation in the whole downstream river. Therefore, in the past, the nature of the Yellow River was "rich in sand, good at siltation, good at determination and good at luck". For more than 60 years, the temporary An Lan, which has been continuously obtained by relying on a huge engineering system, has hidden a greater crisis, and the threat of the Yellow River is still the "great worry" of the Chinese nation.

The main reason for this result should be that there are still deeper limitations and problems in our current thinking of governing the Yellow River. As far as the current observation is concerned, its performance may be in the following aspects:

13. 1.2. 1 The idea of soil and water conservation in the middle reaches is rigid, which ignores or slows down the exploration of other ways to stop and reduce sediment.

So far, the idea of soil and water conservation and sand control in the middle reaches has been "confined to the middle reaches" It is true that the middle reaches of the Yellow River, especially the Loess Plateau, is the main source of sediment in the Yellow River, and 90% of the sediment, especially coarse sand, comes from here. However, I don't know that this "middle reaches" is not a closed and isolated area. It is not only closely related to the downstream, but also closely related to the upstream in terms of soil erosion (sediment transport). It may be naive if we simply discuss and implement the "blocking" of various schemes in the "middle reaches" regardless of the "upstream". This kind of "blocking" is fragile, and the governance practice of the past 60 years tells us that blocking is also very difficult. The reason is not only determined by natural factors such as lithology, climate, vegetation and topography, but more importantly, the most fundamental reason is that the influence of upstream factors on the middle reaches is unclear and mixed. Trying to "separate" the influence of upstream factors on soil erosion in the middle reaches is an imperfect "sand control idea" with no way out. Practice has proved that the rigid idea of "local sand control" is doomed to have little effect.

13. 1.2.2 The research and implementation of "water diversion, confluence and diversion" and other control schemes are all carried out in the lower reaches of the Yellow River, lacking overall consideration and planning on a larger spatial scale in the whole basin and even outside the basin.

Vertically, the research and practice of "water diversion, confluence and diversion" to control the Yellow River, including today, are all carried out in the lower reaches of the Yellow River and have never set foot in the middle and upper reaches. They either "divide water to reduce potential" for flood control, or "jointly attack sand" for scouring and silting, or "find another way" considering the aging of the existing downstream rivers. On the surface, these "downstream measures" seem to have produced certain effects in a short time and in a small scope. However, judging from the current governance results, it is almost ineffective in the whole downstream area for a long time. Here, we can say with certainty that any "downstream measures" may be expedient measures or temporary "speculation" behavior. It is difficult to realize the fundamental control of the Yellow River when the total amount of sediment flowing into the middle reaches has not been effectively changed and the sediment discharge has not been effectively controlled or greatly reduced.

Horizontally, the understanding of the Yellow River in past dynasties was mostly limited to the areas where the Yellow River flowed. Even in the modern harnessing of the Yellow River, its maximum horizontal extension is only the whole Yellow River basin, while the collaborative research and overall planning of harnessing the Yellow River outside the basin are "scarce".

Although in the Ming and Qing Dynasties and contemporary times, some people put forward the viewpoints that "the Huaihe River keeps clear water to wash the turbid current in Huang Zhi" and "the river washes the sand and brushes the bed", which expanded the scope of understanding to areas outside the Yellow River basin. However, they are only mentioned by chance in some cases, and there is a lack of specialized and in-depth and meticulous governance research of "all-round development in many aspects and objectives". For example, it is when the Yellow River meets the Huaihe River (in fact, it is a river basin) that Pan Jixun saw the role of clear water in sand washing. In recent years, in view of the small amount of water in the Yellow River in peacetime, reducing sediment is also an idea. However, this idea has the following shortcomings: First, compared with the world, in China, where per capita water resources are not much, this "single and pure" activity of borrowing water to wash sand is not allowed. If we don't take the road of comprehensive development combining "treatment and utilization", the result will not repeat the mistake of "simply discharging flood and sand into the sea" in history. On the premise of wasting a lot of water resources, this paper tries to improve the scouring and silting environment of downstream rivers. Secondly, on the premise that the sediment interception measures in the middle reaches can not produce obvious sediment reduction, in fact, just like any of the above-mentioned "downstream measures", they can only divert water to "wash sand" but not "reduce sand" well. Under the "pull-up and pull-down" action of erosion source, it is not only difficult to create the dynamic balance of erosion and deposition of downstream rivers, but also will lead to the increase of sediment transport and accelerate the erosion and depletion of the Loess Plateau.

13. 1.2.3 The current effect of "water and sediment regulation" in the lower reaches is not optimistic, and it is difficult to truly create a dynamic balance of river erosion and deposition in the long run.

At present, it is believed that the main culprit of sedimentation and uplift in the lower reaches of the river is the imbalance of water and sediment from Dachuan. There is often less water and more sand, and small water increases sand. Therefore, it is hoped that after optimizing the proportion of water and sediment structure, Bingham-type high-sediment flow can be used in "water and sediment regulation" to achieve the purpose of reducing siltation by washing sand and brushing bed. However, from the past practice of water and sediment regulation in Sanmenxia Reservoir and the current application results of water and sediment regulation in Xiaolangdi Reservoir, the situation is not optimistic. Especially after Xiaolangdi Reservoir loses its function of retaining sand (mainly coarse sand), the downstream channel will restore its original properties to a great extent. Therefore, in the long run, no matter how we adjust the proportion of water and sediment structure, it is still difficult to get rid of the final situation of "rushing at this time, silting at that time, rushing at this stage and silting at that stage" caused by "bundling water to attack sand". As far as the whole downstream is concerned, it is difficult to create a dynamic balance between erosion and deposition.

The main reason is that only by adjusting the proportion of water and sediment structure of the Yellow River system, the total amount of water and sediment and its energy contained in the Yellow River system (basin) itself have not been fundamentally changed.

13. 1.2.4 Up to now, the research and practice of harnessing the Yellow River are mostly confined to the field of water conservancy projects, lacking practical activities such as multidisciplinary cross-consultation and syndrome differentiation treatment such as geological engineering.

So far, the research and practice of harnessing the Yellow River are mostly confined to the field of water conservancy projects. In order to harness the Yellow River, Huang Heren tried his best to use or combine the "Eighteen Martial Arts" in turn and made great achievements. However, due to the limitation of a single discipline of water conservancy engineering, some practices will inevitably have the problem of bias or edge ball, and the contribution is out of proportion to the income. From the perspective of Quaternary geological environment evolution and the formation of the Yellow River basin, there is a lack of multidisciplinary consultation and regulation practice activities in geological engineering and other fields, especially around the development and evolution of the Yellow River and the lack of "health examination and prevention at all growth stages". However, it is not enough to use earth system science to reveal the evolution law of the Yellow River and explore the "healthy Yellow River" at a deeper level, and there is still a problem of "treating the head and feet with a single discipline" in the practice of regulating the Yellow River to varying degrees.

The above shortcomings and limitations of the Yellow River regulation have seriously affected our current Yellow River regulation. It is an important and urgent task for the 2 1 century that how to break through the shackles of the previous thought of controlling the Yellow River, jump out of the limitations of the above-mentioned strange circle in time, and find another way to seek the fundamental way of "controlling the Yellow River with new sand".