1.2.3 Industry and agriculture

The Yellow River Basin has been the agricultural economic development zone in our country since very early time. The Hetao Plain between Ningxia and Inner Mongolia Autonomous Regions on the upper reach is a successful model project of ¡°Greenland Agriculture ¡±for the improvement and practices on the arid-area. And the basin between Fen River and Wei River on the middle reach is one of the major grains and cotton production bases of our country as well, like the wheat, cotton, oil and tobacco agricultural products, which plays an important role in China.

A number of newly built industrial bases and cities have been set up in the Yellow River basin. Energy industries including coal, power-generation, petroleum and natural gas have obviously superiority in resources. The raw coal production output occupies more than half of the total that of the country and petroleum production output roughly covers one fourth of the nationwide. Nonferrous metallurgical industries, like Lead, zinc, aluminum, copper, molybdenum, tungsten and gold as well as rare-earth industry also have comparative superiority. And the textile industry has an important position in our country as well.

1.2.4 Culture and human activities

The Yellow River Basin is the cradle of Chinese nationality. In the very long historical period, the Yellow River basin has been the center of politics, economy, and culture of China. As early as one million years ago, ¡°The Lantian Man¡± had been living in the Yellow River Basin, and ¡°Dali Man¡± ¡°Dingcun Man¡± and ¡°Hetao Man¡± etc. ancestors one generation after another had been living and working along the Yellow River, and created magnificent ancient civilization. The remains of ancient culture like Yangshao Culture, Majiayao Culture, Dawenkou Culture and Longshan Culture can be found everywhere in the whole river basin from upper reach to the lower reach.

About 4000 years ago, the tribe had been set up in the Yellow River Basin typically represented by Yan Emperor and Huang Emperor, and descendants of Yan and Huang Emperors mixed together with other tribes and established ¡°Chinese Nation¡±. From the founding of the Xia dynasty in 21 century BC to now, more than 4000 years have passed. China¡¯s capital has been settled in the Yellow River basin for 3000 year odd. Four out of the six most famous ancient capitals in China are in the Yellow River basin.

Natural landscapes of the Yellow River basin are grand and spectacular in viewing. Tourist resources are very rich. Mountain Riyue, Mountain Jishi, Mountain Helan, Mountain Liupan, Mountain Luliang, Mountain Zhongnan, Mountain Hua, Mountain Tai, and the Longyangxia Valley, Liujiaxia Valley, Yumenkou Valley, Sanmenxia Valley, etc. are precipitous and deep. The famous Hukou waterfall is located in the Valley between Shanxi and Shaanxi, Water gallops and roars through the valley with a heroic spirit that conquers mountains and rivers.

1.3 History of river evolution

The formation of the Yellow River has passed through long geological era. As early as one million years ago, it was Pleistocene, many lakes spread within the Yellow River Basin, they did not link with each other, and each lake had formed its independent water system. But later on, the movement of the Himalayas made a large area of earth rising and falling vertically, and western plateau quickly rose and North China plain gradually subsided. The drop of topography from west to east became bigger. In addition, the lakes and basins had merged with each other gradually by the long term erosion and invasion, and finally, the large river had been formed as a whole from the upper to the lower part. By the synthetic analysis and deduction, it has 1.5 million years long history since the formation of the ancient Yellow River. The Yellow River got its name because of the yellow color of muddy water, and in the ancient books, it was called the River. The Yellow River was firstly called in the ¡°Book of Han Dynasty¡±.

1.3.1 River channel shifting and flood protection area

1.3.1.1 Shifting of the river channel

In the past historical period, normally, there were no great shifts occurring for the river channel of upper and middle reach. Only the river channel on the lower reach shifted frequently. Taking Zhengzhou city as axle center, it shifted to Tianjin in the North, and reached Yangtze River and Huaihe River in the south, crossing the plain among the Yellow River, Huaihe River and Haihe River with total area of 250,000 km². And tracks of the shifting can be found almost everywhere. There were eight times of major shifts occurring on the lower reach of the Yellow River during 2000 years odd since the Warring States to now. The first major shifting occurred in the fifth year of Zhouding Emperor (602 BC) by the historical record. Since then to the early year of Jin Dynasty, it was 1700 years odd, and the lower river channel only shifted in the northern part of the Yellow River and flowed into Bohai sea. Since second year of Jianyuan of South Song Dynasty (1128 AD), Duchong who was the officer in charge of Dongjing (Kaifeng city) breached dykes of the Yellow River in order to stop the troops of Jin State going to the south, which caused the Yellow River flow into Huanghai sea crossing Huaihe River. After that time, the shifting had occurred frequently in the south of current river channel for 700 years. In the fifth year of Qingjianfeng (1855 AD), the dyke breached at Tongwaxiang (Dongbatou, Lankao county, Henan province) which caused the Yellow River flow into Bohai sea after crossing the Daqinghe River. In 1938, the Guomindang Authority burst dyke at Huayuankou near Zhengzhou City in order to stop Japanese invasion to the west, which caused the Yellow River flow into Huaihe River. In 1947, after closing the dyke at Huayuankou, the Yellow River recovered its old course and remains its downstream channel till now.

At present, the river channel has been formed steadily between the dykes during the process of long-term flood release and sediment transportation. The riverbed is normally 3-5m higher than backside ground on average, the maximum 10 m higher, and will be raised 0.05-0.1m high on average annually. The section above Gaochun is the meandering section with width of 5-20m between dykes. The section between Gaochun and Taochengfu is called transition section, 1.5-8.5m wide between both dykes; and section between Taochenfu and Lijing is called wandering section with 0.4-5m width between both dykes; the section below Lijing is called estuary section. And 1 billion ton sediment will be transported into estuary area on average annually, with extending of aggradation, the new land with area of 25-30km² will be created annually on average. In order to control the shifting of river mouth, and properly arrange channel to the sea, the river channel have been artificially shifted for three times since 1949. The current channel to the sea has been formed since artificial shifting of Qingshuigou in 1976.

1.3.1.2 Protection area of flood control

The protection range of flood control on the lower reach is taking Zhengzhou as axle center, and it reaches Haihe River in the north, and Yangtze River and Huaihe River in the south, the total area is 120,000km². Based on the information of historical floods, combining with analysis and deduction of variation of topography and ground matters, if the dyke burst once in the north or in the south and keeping the current river channel without occurrence of major shifting, the maximum impacted range in the north would be 33,000 km² and 40,000 km² in the south. The total area would be 120,000 km², and cultivated land 7.33 million hm², population 78.01 million within flooding affected area.

1.3.2          Flood features of the river

The Yellow River has four kinds of floods in a year called peach flood, summer flood, autumn flood and ice run flood. The summer flood is caused by heavy storms. The autumn flood is caused by an unbroken spell of wet weather during the period from September to October. The summer flood and autumn flood are the most dangerous, usually called ¡°summer and autumn flood¡±. The ice run flood is caused by ice blocks in winter which make the water level rising suddenly and threatening the safety of the embankments in the sections of Ningxia, Inner Monggolia, Henan and Shandong. The peach flood happens during March and April when peach trees are blossoming and ice and snow melt in the upper reaches, causing water level rises in the lower reaches.

The floodwater, being characterized by high flow peak, short duration and abruptly rise and fall, mainly comes from the Middle Yellow River. There are three floodwater original sources on the Middle Reach; the first one is between Hekouzhen-Longmen, the second one between Longmen-Sanmenxia and the last between Sanmenxia-huayuankou. Different floods from different areas will all form their own major and extraordinary floods in different formations at Huayuankou station. The occurrence of flood above Sanmenxia is called ¡°Upper Main Flood¡±. For events of floods of 1843 and 1933, both are the typical ¡°Upper Main Floods¡±, which are characterized by high flow peak, huge flow and sediment that normally forming high sediment laden flow and the flood-control is significantly threaten. The flood in between of Sanmenxia to Huayuankou is called ¡°Lower Main Flood¡±, the floods of 1761 and 1958 are the typical ¡°Lower Main Flood¡± with characteristics of water level rise and fall abruptly, high flow peak, less sediment laden flow and short predict period that had mostly threaten the flood-control in all. The historical survey shows us that the biggest flood occurred in 1843 with peak flow 36,000 m³/s at Shanxian Observation, and the observed occurred in 1958 with peak flow 22,300 m³/s at Huayuankou Observation.