A Hyperconcentrated Flood Event of a Tributary of Yellow River (1994/09)

【Introduction】On September 1, 1994, there was a 50-year hyperconcentrated flood event of Beiluo River, tributary of Yellow River at its middle reach in northern China. Flow discharge is around 6,280 m3/s, sediment concentration is 690 kg/m3. Total sediment in 4 days of this event is almost 0.136 billion tons, and total water volume is 2.04 billion m3. This video shows the flood water passing through Daja County, Shannxi Province, China. The flood almost reached the roof of a building here.

Enjoy an Award-winning Song of "Life of the Yellow River"!

【Enjoy】A song "Life of the Yellow River", lyrics by Yiping Chao and the music by Xiaolu Wang. This is a song about keeping the healthy life of the Yellow River, and it has received many awards in China. You can also enjoy the beautiful scenery of the lower Yellow River.

【Lyrics in English】Pentium endless torrents, are your pounding pulse. Traveling through eternal time and space, are the green waves on both banks. Ah, Yellow River, my dear mother, coming along with grand songs, you cast a flow of history. Ah, take care of our mother river and dress her up, we will enjoy the sunshine and green with you together. Ah, love our mother river and repay her, we will sing the hymn of life with you together.

River course changing and levee breaching so many times, should not be your characteristics. River bed running dry again and again, is your silent whispers. Ah, Yellow River, my dear mother, keeping the healthy life of you, is our responsibility as your daughters and sons. Ah, take care of our mother river and dress her up, we will enjoy the sunshine and green with you together. Ah, love our mother river and repay her, we will sing the hymn of life with you together.

An Amazing Bridge in a Hyper-concentrated Flood Event in 1994

【Introduction】On September 1, 1994, there was a 50-year hyperconcentrated flood event of Beiluo River, a tributary of Yellow River at its middle reach in northern China. Flow discharge is around 6,280 m3/s, sediment concentration is 690 kg/m3. Total sediment in 4 days of this event is almost 0.136 billion tons, and total water volume is 2.04 billion m3. This video shows the flood passed through a bridge at Baishui County of the upper reach of Beiluo River. It is really amazing that the bridge can sustain such a huge flood event with a large amount of sediment!

Recent Pictures of the Lower Yellow River in China

Fluid Mechanics in Ancient China - How Do You Know the Weight of an Elephant?

This is a story about how the knowledge of fluid mechanics was first used for the real life problems in ancient China....Let me know your solution to this problem in the end!!!

More than 1000 years ago, there once was a child called Chong Chao, a very clever boy beloved by his father, Cao Cao, the prime minister in feudal China of the Kingdom Wei.

One day, his father was presented an elephant by the southern envoy. It was such a tall and large animal that nobody had ever seen at that time in Northern China. A question suddenly came into the father’s mind: how much does the elephant weigh? The understrappers, accordingly, assigned dozens of soldiers to build a huge steelyard with a big plate, where the elephant can be placed and weighed. However, the elephant is so heavy that wooden weigh-beam can not sustain its weight and cracked. Someone suggested to kill the elephant, cut him into pieces, and weigh each part individually, but the elephant will not be alive. No one can work out of any good idea to weigh an alive elephant.

Right at this moment, seven-year-old Chong jumped out and said to his father: "I can weigh it." The surprised father smiled: "You are only a little boy, what is your opinion? " Chong winked naughtily: “follow me, and just do what I required”, then ran onwards to the lake of the palace. Those adults who saw that all shaked their heads, and thought it was just a little joke. But his father Cao abandoned his dubitation, he called others to follow the little son to the lake to see how the elephant would be weighed. 

Dear blog reader, could you let me know how the elephant was weighed by Chong? Leave your message, thanks! Hint: Lake...

Yellow River Blues (Part 1 and 2)

【Introduction】As the sixth longest river in the world, the Yellow River and its basin have been associated with China's prosperity for thousands of years. In recent decades, rapid economic development has increased the river's pollution and sediment levels, posing major challenges in managing its water for agriculture, industry, power generation and domestic uses. A new study shows that climate change can reduce the volume of water, add pressure on all sectors to share water more efficiently and carefully. The same imperative of integrated river basin management applies to other river basins across China and Mongolia in northeast Asia.

This film captures the highlights of a 2008 study, Vulnerability Assessment of Freshwater Resources to Environmental Change, carried out by researchers in China and Mongolia for the United Nations Environment Program (UNEP).

Part 1

Part 2

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.