The Yellow River is the second-longest river in China after the Yangtze and the sixth-longest in the world. Rising in the Yueguzonglie Basin 4.5 km above sea level in the northern side of Bayankala Mountains, the Yellow River loops north, bends south, then flows eastwards for 5,464 kilometers until it empties into the Bohai Sea.
As the world’s most silt-laden river, the Yellow River owes its name to the perennial ochre-yellow colour of the water and is famous for its excessive sediment. The river has an average annual runoff of 58 billion m3 and the average annual sediment transported in the Yellow River is approximately 1.6 billion tons. These numbers make the average annual sediment concentration as high as 35kg/m3, which is unique compared to other river courses in the world.
The maximum sediment concentration recorded at Xiaolangdi gauging station in 1997 is as high as 941 kg/m3. Both the average sediment concentration and the total annual sediment load of the Yellow River are the highest in the world. For instance, the Ganges of India carries the second-largest sediment load, corresponding to an average of 1.45 billion tons of sediment annually. But its annual runoff, 371 billion m3, is more than six times that of the Yellow River. The Colorado River of America, another famous silt-laden river, has a very high level of sediment concentration of 27.5kg/m3. However, its annual sediment load is 135 million tons, less than 10 percent of the Yellow Rivers’.
Known as the cradle of Chinese civilization, the earliest human settlements found in the Yellow River basin date back to a million years ago. The basin is the birthplace of ancient Chinese civilization and the most prosperous region in early Chinese history. The Han Chinese, comprising 98 percent of the country’s population, claim to be descendants of the Yan Huang Emperor (2697 to 2597 BC); they lived along the middle and lower reaches of the river. Two of China’s famous and influential philosophers, Confucius (551 to 479 BC) and Mencius (372 to 289 BC), were born and lived in the Yellow River basin.
Currently, home to hundred and ten million people-approximately nine percent of China’s population-the river drains a basin of 795,000 km2 As the main water source of northwest and north China, the Yellow River accounts for 2.2 percent of the total runoff of all rivers in China, but supports 12 percent of the nation’s population and shoulders the water-supplying duty of 15 percent of the irrigation area.
Managing the Yellow River reflects the origins and evolution of Chinese Bureaucracy. For over 2000 years, Chinese emperors in every ancient dynasty regarded the management of the Yellow River as a great task concerning a nation’s stability and prosperity “Whoever rules the Yellow River, rules China,” said Yu the Great (2200-2100 BC, 大禹治水). Yu was famous for introducing an effective method of flood control.
The Yellow River watered the cradle of Chinese civilization, but also rose in tremendous natural disasters caused floods and droughts. Immense efforts have been made both to control the river to avoid natural disasters, and also to develop the river as a resource. Recorded in the History of Former Han, the first major flood in China was caused by a disastrous channel-changing of the Lower Yellow River in 2297 BC.
Shortly after this flood, Emperor Yao appointed the first Minister of water management for the Yellow River. Since 540 BC, there have been 1590 recorded dike bursts along the lower Yellow River and 26 significant river channel shifts. Due to low precipitation and uneven distribution of rainfall, the river basin has always suffered from serious droughts. From 1766 BC to the present, over 1070 major droughts have been recorded. For instance, the 1877-1879 drought lasted three years, causing 13 million deaths. The 1929 drought, together with the WWII and the Chinese Civil War between 1927 and 1949, resulted in over an estimated 34 million deaths.
Two historial approaches to managing the Yellow River
After 1949, China’s government took the lead in managing the Yellow River. There were two historical strategic approaches to management of the Yellow River; namely, narrow channel and wide channel strategies. The narrow channel strategy refers to confining the river within high levees. The concept of narrow channel involves encouraging fast flow which keeps sediment in suspension, thus boosting the sediment transport efficiency.
This approach, however, increases potential flood vulnerability due to limited reserve capacity for major floods, and so even the high levees will inevitably be overtopped in periods of very high flow. Costs for constructing and maintaining the levees are also enormous. The wide channel strategy works in the opposite way; it suggests making space for floods by confining the river in a wider flood plain thus allowing a much higher capacity for flood discharge. With small diversion dams, the mainstream can be kept at the centre of the channel, avoiding the problem of scouring of the levee foundations.
This option, however, requires that more floodplain area is reserved for flood alleviation, and further promotes silt deposition, which leads to increase in riverbed level. In the 1950s and 1960s, a traditional narrow channel approach involved strengthening and raising the levees. Since the 1960s, a more integrated approach has been implemented to manage the Yellow River; this approach includes engineered spillways and levees set to protect a wider river course. Two tiers of levees were built: an outer set to confine large floods, and an inner one to concentrate the low-flow river and encourage it to scour away its load of silt.
The runoff in the Yellow River has gradually reduced since the 1980s. In addition to this reduced runoff increased socioeconomic development that followed China’s Open Door Policy (1979) required more water resources for agriculture, industrial, and domestic uses and increased the amount of wastewater discharged back to the river without adequate treatment. YRCC developed a new framework in 2004 to restore the river’s ecological condition and support socio-economic development: the One-Four-Nine-Three Yellow River Management Strategy. The ‘One’ refers to the new concept, to maintain the healthy life of the Yellow River. The ‘Four’ refers to the “Four Nots Objectives”; namely, the dike does not breach, the channel does not have zero-flow, the pollution does not exceed the standard, and the riverbed does not rise up. To achieve this, YRCC proposed nine approaches (listed below). Finally, the ‘Three’ represents three technical tools adopted: a numerical model, a physical model, and a comprehensive database of the Yellow River.
Nine approaches to maintain the health of the Yellow River are:
1. To reduce the sediment load.
2. To manage the water resources utilization more effectively.
3. To increase the water resources through diverting water from other river basins.
4. To build the water and sediment regulating system.
5. To work out and execute a scientific and rational general plan for regulating the downstream channel.
6. To create a runoff process that does not cause shrinkage of the main channel.
7. To adopt water resources protection measures that meet the requirement of water quality functions.
8. To harness the estuary of the Yellow River so as to maximally reduce the impacts on the river channel.
9. To create a runoff process that meets the requirement of maintaining the benign cycle of the ecological system in the delta region.
Yellow River stands at the centre of emerging challenges in terms of water security, population growth, economic development, food production, as well as climate change. This addresses the need for a coherent multidisciplinary regime to manage basin water resources and their users in order to identify and to meet environmental and socioeconomic demands. The new management regime of the river basin reflects the institutional capacity to recognize and incorporate broader objectives and long-term perspectives.
This article is based on the research paper Integrated river sustainability assessment: case studies of the Yellow River and the Ganges. Huijuan Wu is a research fellow at the Institute of Water Policy, Lee Kuan Yew School of Public Policy, National University of Singapore.