Nov. 26, 2014
Yellow River Decade (5) Examining silt at the Sanmenxia Hydropower Station

 

Reported by: Lina Wang and Yongchen Wang 

We had never expected that on our first visit to the Sanmenxia Hydropower Station, the silt in the Yellow River would put on such a wonderful "show".

It was 7am on August 15, 2010.  As our bus had been having some problems, all 37 passengers disembarked and decided that the focus of today would be to go and check out the Sanmenxia Hydropower Station. From the outset, we had given up on Sanmenxia as we felt that the jury had already delivered its verdict on the project: a fairly unanimous vote of no confidence.   In particular, our colleague Qi Pu, senior engineer from the Yellow River Water Resources Council, held firm views on the taming of the Yellow River, insisting that the idea to construct Sanmenxia was fundamentally flawed.

Mr. Qi Pu had also gone to great lengths to contact a guide from the Sanmenxia area with a direct connection to the project to explain it to us in depth.

 


A map of the Yellow River

A topographic map of the Yellow River Basin

A model of Sanmenxia

Cut down the middle

The tour guide told us that Sanmenxia Dam was China’s first large-scale water management project constructed on the Yellow River and was now honoured as "The Great Yellow River Dam." The dam is located in the northeast of the Sanmenxia district in Henan province, neighboured to the north by Shanxi Province and to the west by Shaanxi Province, in an area known as "The Golden Triangle." The first ground was broken in April 1957 and in only about four years the bulk of the dam’s construction was virtually complete.

Our  guide proudly explained that Sanmenxia was constructed entirely using manual labour, whereas dam construction these days, including the Three Gorges Dam, is all done my machines. She drew our attention to a poem by He Jingzhi called "The Sanmenxia Dressing Table", but explained that she would only recite a couple of lines since it was rather long. One of the lines she chose was written before the construction of the dam while the other was written afterwards. The first was: “The waters of the Yellow River flow from heaven” and the other one was: “The waters of the Yellow River flow from the hands of men”.
In the guide’s view, the construction of the Sanmenxia Dam was simply a testament to the ability of  human beings to manipulate the Yellow River.

“The waters of the Yellow River flow from the hands of men”

  The “dressing table”, which has since been inundated by water.

  The canyon pictured is no more.

These two photos of what was called the Sanmenxia “dressing table” or “dresser ”are extremely rare, as they show the which now rests at the bottom of the reservoir. They are also the sole remaining record of what the area looked like before the dam’s construction. Photos are the only reference we have of the “Goddess River Gorge”, whose sheer cliff faces were also inundated after the dam’s construction.
In this highly biased exhibition centre, surprisingly we did obtain some new information: From the two photographs we learned that the Yellow River floods four times a year, with the silt content rising sharply during flooding months.


Information of the four flood periods of the Yellow River.

Samples of river water.

The four flood periods of the Yellow River are named Spring flood, Summer flood, Autumn flood and Winter Flood. The names of the floods are pretty self-explanatory; however, what wasn’t obvious from the exhibition was whether the construction of Sanmenxia Dam had affected the annual flood cycle.

Examining the row of twelve test tubes in this display case, I had an inspiration. Originally, we chose to come on this trip to take a number of water samples and examine the differences in water quality between them. However, several experts we spoke to felt that in reality, this method of fieldwork would not offer any significant insights. This is because there was nothing profound about the sites or periods where we were taking samples. However, if we were to use the samples collected on this trip to monitor sediment instead of water quality, perhaps we would be able to determine variances in the sediment levels along the entire Yellow River. The realization of new possibilities for our water samples would end up being the most productive result of the day.
The exhibition centre contained so much material that would be considered controversial by today’s standards. Touting only the project’s triumphs while failing to mention a single word from alternative points of view, the exhibition actually provoked a sense of pity towards it.

 Of course, the times are always changing. Thinking back to the past, Tsinghua University water management expert Professor Huang Wanli, and Wen Shanzhang, an intern from the State Administration of Radio, Film and Television (SARFT) put forward a challenging view of the Sanmenxia Dam project. They argued that the use of high dams and large reservoirs to store water and capture sediment was not suitable for the Yellow River with its  high silt content, and would lead to numerous problems upstream. However, during that period when the dominant ideology of the times was to build a new China that was bigger, better and bolder, any opposition to  the dam’s construction  was considered almost counter-revolutionary.


The islands depicted in this mural have since been submerged in water

Stepping across two provinces

As expected, the advice of Huang Wanli and Wen Shanzhang, and barely a year into the engineering project, 1.5 billion tonnes of silt had already been deposited into the reservoir. Once the project began generating power, it not only failed to contain the silt, but also created problems on the upper reaches of the Wei River. At this location a dam had been built that steadily raised the height of the riverbed, leading to increased flooding and the salinization of more than 50 million mu (8.3 million acres) of farmland on the Guanzhong Plain.

In 2006, I went to investigate Hua County in Shaanxi Province. Locals showed me one result of the continuously rising Wei River riverbed: a bridge over the river had been buried so deeply by silt that they were forced to build a new bridge where the original bridge had once stood. It had then reached the stage where a bridge on a bridge soon became a bridge on a bridge on a bridge.


When I visited the Wei River the previous year in 2005, the Autumn floods led to the Wei River disaster. By Chinese New Year of the following year, the water had still not receded and victims were still living in emergency shelters.

According to senior engineer Qi Pu , although this project was considered one of the biggest engineering failures since the founding of the Republic,  it is undeniable that the lessons it provided were incorporated into the construction of the later projects such as Xiaolangdi Reservoir and the Three Gorges Dam.


The overwhelming force of the silt


Silt in the reservoir.

 Regardless of peoples’ attitude towards the Sanmenxia Dam Hydropower Station before our visit, all of us could not help but be struck by the sight of the battle occurring before our eyes once we saw the site up close: The Yellow River had morphed into an entirely different form; an awesome sight that was worthy of a painting. In one sense, you could say that the river had been ‘sculpted’ by manual labour into a form that laid bare the inherent beauty of its raw power.
 
Yesterday we witnessed the thundering waves of water and sediment being released from the Xiaolangdi Reservoir. And today again the Sanmenxia Dam shook heaven and earth as the reservoir was emptied of silt. Standing above this world of silt, it looked like as if the silt was dancing; just looking at photographs of it causes the mind to wander off into far-away places. I think I speak for most people when I say that the fantastic world of silt had captured my interest far more than the intricate details of hydroelectric generation.

A world of silt

The howling silt

Silt, silt and more silt!

Qi Pu tells us that the process of flushing the accumulated silt out of the reservoir involves draining its contents and then using upstream floodwaters to wash away any remaining sediment. This not only sends the existing build-up of silt further downstream but also brings new deposits of silt from upstream. As a result, the silt discharged from the dam is dense, comprised of both accumulated silt and newer silt from upstream.


Qi Pu has devoted his whole life to understanding the Yellow River, and considers himself a scholar on the topic. In recent years, wherever he goes, he articulates his position on the river’s management to our national leaders, to his colleagues and to people in different industries. Even those who don’t agree with him entirely have to admire him for his persistence in making his case.


In this photo, the Sanmenxia Power Plant is not generating electricity, but discharging sediment.

Collecting water samples.


A water sample from Sanmenxia Reservoir.

Back on the bus, Qi Pu tells us that the sediment contained within the Yellow River is deposited naturally during the flood season and that these floodwaters ultimately disperse the sediment into the sea, which has far-reaching significance for downstream river management. The large number of reservoirs on Yellow River, the construction of reservoirs on the Yellow River basin in groups, the application of soil and water conservation practices, and the development of irrigation have caused big changes to the underlying riverbed. These changes to the riverbed have dramatically decreased the frequency of floods and reduced the range of the river’s peak flow rate. In order to maintain the natural process whereby floodwaters shape the riverbed and transport sediment to the sea, Qi Pu explained that we should cease broadening the river and abstain from trying to limit its peak flow. In recent years, we have adopted a new view of the Yellow River’s natural narrow, deep channel and the cyclical floodwaters that transport silt downstream. We are beginning to understand that the downstream waters of the Yellow River have a strong capacity to transport sediment and discharge floodwater, and that silt build-ups are not necessarily related to the river channel’s degradation. This sort of thinking is pointing the way for how the lower reaches of the Yellow River can be administered going forward. Until now, it had been thought necessary to construct artificial levees along the river.  In the future, however, allowing silt to build up could lead to the formation of natural levees.

According to Qi Pu, after the reconstruction of Sanmenxia reservoir, the principle of storing clear water and discharging muddy water has greatly reduced the silt content of the water. As a result, the upper channels of the River, above the town of Huayuankou are almost clear. Permanent settlements have developed on the Wen and Meng riverbanks around the Xiaolangdi Reservoir. Since the Xiaolangdi Reservoir has gone into operation, most of the banks along the lower river have suffered erosion. There are sections of the river above Gao Village where the river’s average flow-rate has increased to more than 5000m3/s. However, in places where the river becomes wide and shallow, the most advanced practices available are urgently needed to restabilize the riverbanks and restore deep and narrow channels.  After many years of adjusting the sediment levels of the Xiaolangdi Reservoir, we should be able to restore the natural cycle of silt build-up and discharge that occurs during flood periods, and prevent the main riverbed from rising too high.  If the main channel’s current can be increased, the flood plain will decrease and the debate over constructing new levees will no longer be necessary.  This would be the rational solution to all these problems encountered along the riverbanks. It should be noted that the approach to river management we are currently advocating, in which silt is allowed to accumulate according to natural patterns, applies to wide sections of the river up to the Xiaolangdi Reservoir. It does not account for the unique circumstances of the lower reaches of the Yellow River, downstream of Xiaolangdi Reservoir.  As it does not reflect the unique conditions along the entire Yellow River, it should not be taken as such.


An expert in front of Sanmenxia Reservoir.

Recording the roar of the mud.

Wang Jian, another expert who was traveling with us, explained how from an ecological perspective the production of hydropower can disrupt the delicate balance of nature.  Meanwhile, Luo Kanglong asked why we hadn’t seen a single wetland at any of the places we had visited on our fieldtrip. Was it because wetlands had never existed at all, or was it because the ‘taming’ of the Yellow River had caused the natural surroundings to lose their natural free and wild appearance?

Part of an inscription on the reservoir which reads: “The Yellow River is calm”

The inscription on the reservoir reads: “The Yellow River is calm, the country is prosperous and the people live in peace”

From an academic perspective, it is hard for those of us with a strong concern for the environment and the health of our rivers to speak with Qi Pu and not feel a strong sense of dismay. However, in recent years, as increased attention has been paid to river management and as our understanding of hydropower has also grown, the question is not whether or not we should build hydropower stations, but where and how to build them in order to avoid future disasters.

Often technical problems are easy to solve. What is difficult is juggling the interests of the upper, middle and lower reaches of the river. While we can use a variety of methods to “tame” the Yellow River, it is pointless to try to change its natural state. In some places the silt will build up, while in others it won’t. If we draw too much water here, there will be too little water left there. When we are confronted with problems, perhaps we should take a moment to consider whether it is the river that requires modification or human behavior that requires modification.  Perhaps it is possible to reduce our own self-interest and have more consideration for those people who live along the entire Yellow River basin. Maybe when we dream of the huge economic returns that engineering projects and power generation bring, we should also think of the ecological and social consequences of our endeavors.

A view of the entire Sanmenxia Reservoir

The Mainstay Stone, saved by Premier Zhou Enlai.


According to legend, when the Great King Yu (the third of the legendary emperors who created the Chinese state) was managing the country’s waterways, he once came to this site and found a huge stone blocking the river. With two swipes of his sword, he sliced the stone into three pieces: Renmen (Peoples') Stone, Shenmen (Spirits') Stone and Guimen (Devils') Stone. In doing so he created three channels, or gateways for the river to flow through and it is from this myth that the name "Sanmenxia" (Gorge of the Three Gateways) is derived. Nowadays, these three rocks are inundated by water and have become foundation stones.

Anthropologist Luo Kanglong tells us that from the source of the Yellow River to the point at which it reaches the sea, there is evidence of Qi Lu Culture, Zhong Yuan Culture, Jin Shang Culture, Mongolian Culture, and Tibetan Culture following each other in succession. However, with the construction of over 3000 reservoirs of varying size along the Yellow River, we may never know how many other cultures once thrived along the river as we have not had enough time to study and record them.

Nowadays, there still exists a large stone in the water in front of Sanmenxia Dam. Remarkably, though the river has been rising and falling over thousands of years before the dam's construction, this stone has never been inundated by water. For this reason, it is called the Mainstay Stone and has often been taken as a symbol. When the dam was built, some people suggested blowing up the stone, fearing that it would block the current and affect the generation of electricity. However, then Premier Zhou Enlai issued a decree stating that the stone should be protected and the stone proved to have no effect on electricity generation.

Is that a water reservoir or a silt reservoir?

A vista of silt.

From the drainage outlet spews a torrent of mud that looks a yellow dragon struggling to wriggle itself free. The poet Li Bai once wrote of the river: “See how the Yellow River’s waters move out of heaven, entering the ocean, never to return.” It is rare that one would come across such a poetic line these days and generally we can only imagine such a scene.

So it comes as a surprise when, while waiting for the bus to be repaired one afternoon, we visited Shaanxi National Park in Sanmenxia city and were able to witness a section of Yellow River in all its natural glory.  Perhaps it is because we had spent the last two days examining the tremendous energy of the artificially-constructed Xiaolangdi Reservoir and Sanmenxia Dam that we felt how natural and untouched the Yellow River appeared here.  Moreover, it is rare to see rivers in their natural state these days; such a precious experience that revives the hope of maintaining a harmonious relationship between people and rivers should be treasured.

The natural Yellow River.

Recording the river now to preserve it for future generations

The following day we would go to Tongguan, at the mouth of the Wei River. The ancient County of Tongguan, which had been located in the reservoir area, was entirely relocated after the construction of Sanmenxia Dam.  We were going to meet the people that live there now and see how their lives were progressing. There, we would seek out families whose lives on the Yellow River we had been tracking over the past ten years and will continue to track for the next ten.

 

 

Translator: Ding Xiaoxin; Li Xiaoxia

Proofreader: Jeremy Sung; Ken





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