Huang Ho

(also Great Huang Ho Coalfield), a collective name for the group of large coalfields that are located along the middle and lower course of the Huang Ho and that formerly were regarded as a single coal-bearing area.

The central group of coalfields includes the Shansi Coalfield, which, with an area of 150,000 sq km, is China’s largest. The coal of the Huang Ho is found in Upper Paleozoic and Mesozoic deposits. Important Paleozoic deposits formed during the Upper Carboniferous (Taiyüan formation [svita]) and the Lower Permian (Shansi formation). The Taiyüan formation has 6–13 workable seams, with a combined thickness of 18–25 m; the Shansi formation has 2–3 workable seams, with a combined thickness of approximately 4 m. The largest deposit being worked in Shansi is the Tat’ung, which covers an area of approximately 2,200 sq km, has total coal reserves of more than 100 billion tons, and produces approximately 20 million tons annually. The principal formations of the Huang Ho Coalfield are the Tat’ung (Lower Jurassic) and Taiyüan. The former has as many as 12 workable seams located close to one another, with a thickness of 0.6–5.7 m each. In addition to the Kaip’ing, one of the Huang Ho’s oldest deposits, the major known deposits are the Hsishan, Yangch’üan, (Yenyüan), and Chinghsing.

The Huang Ho Coalfield contains hard coal. The Paleozoic is represented by low- and medium-ash coal, 18–29 percent of which is volatile matter, and by low-sulphur coal, primarily caking and coking coal, with a heat value of 31–32 megajoules per kg. The Jurassic coal has a volatile-matter content of approximately 31 percent. Because the workable seams of the Huang Ho Coalfield are comparatively simple in structure, slope gently, and lie close to one another, they are easily developed.

(also Yellow River), a river in East China; one of the great rivers of Asia. The Huang Ho is 4,845 km long and drains an area of 745,000 sq km (according to some data, 771,000 sq km). It rises in the eastern part of the Tibetan Highlands, in the Payenk’ala Shan, at an elevation of more than 4,000 m. In its upper course, the river crosses the Odon-Tala Basin and two lakes, Oling Hu (Orin-Nur) and Chaling Hu (Zharin-Nur); in this stretch its fall is relatively slight. Emerging from the highland, the Huang Ho cuts its way across the southeastern spurs of the Kun-lun Mountains and the Nan Shan through deep gorges, forming rapids and waterfalls. As it receives numerous tributaries, such as the T’ao Ho and the Huang Shui, the Huang Ho gradually becomes a large mountain river with a torrential current.

In its middle course, the Huang Ho forms a large loop, flowing initially northward along the western boundary of the Ordos Plateau, then eastward across the Hot’ao Plain, and finally southward across the Loess Plateau. In these areas of semidesert and steppe, which extend for approximately 2.000 km, the river’s water volume increases only slightly, and in the Hot’ao Plain, where water is lost through irrigation and seepage, the volume actually decreases. Intensively eroding the Loess Plateau, the Huang Ho cuts deep gorges in the friable rocks; these gorges alternate with broader sections of the river valley. There are small waterfalls and cascades including the Huk’ou Waterfall, which has a height of approximately 17 m.

The Huang Ho and such tributaries as the Wuting Ho, Wei Ho, and Fen Ho carry a considerable sediment load, which gives their waters its characteristic yellow color—hence the name “Huang,” or “Yellow.” Below its confluence with the Wei Ho, the Huang Ho turns eastward and crosses the mountains of Shansi through deep, rocky gorges, such as the Sanmenhsia; its lower course then flows along the North China Plain for a distance of 700 km. The Huang Ho empties into the Pohai Wan (Gulf of Chihli), where it forms a delta.

The Huang Ho is fed primarily by rain, but in the mountainous areas of the river basin it is also fed by snow. The mean flow rate is 1,105 cu m per sec at the city of Lanchou and 818 cu m per sec at Paot’ou; in the lower course, at Lek’ou, the rate is approximately 2,000 cu m per sec. High water occurs in July and August during the monsoon season. The mean flow rate in the lower course reaches a maximum of 22,000 cu m per sec and during catastrophic freshets may reach 30,000 cu m per sec. The river carries a water volume of approximately 50 cu km per year. During high water, the water level sometimes rises by 10–20 m in the gorges and 4–5 m in the plains. In winter the river carries a small amount of water, and it freezes over for 2–3 months in its middle course and 2–3 weeks in parts of the lower course.

The Huang Ho carries an average of 35–40 kg of suspended load per cu m; the load is estimated to total 1.3 billion tons per year, which places the Huang Ho at the head of the world’s great rivers in this category. In the lower course large quantities of silt are deposited on the riverbed, which consequently rises over time. On the North China Plain the riverbed is generally 3–10 m higher than the surrounding lowland. This disparity has created a constant threat of flooding, and as a preventive measure the Huang Ho and its tributaries have been lined with dikes 5–12 m high that extend for a distance of approximately 5,000 km. The alluvial deposits cause the delta to grow by as much as 290 m annually.

In the past the dikes have given way, causing the riverbed to shift markedly on numerous occasions. Over the past 4,000 years the lower course of the river has moved more than 20 times, on seven occasions dramatically; the attendant catastrophic floods gave the river its nickname, “China’s Sorrow.” Major changes in the river’s course, which have been as great as 800 km, have caused the Huang Ho, on separate occasions, to merge in the north with the Hai Ho and in the south with the Huai Ho; the river has emptied into the Yellow Sea both north and south of the Shantung Peninsula. The last major shift of the river’s course occurred in 1938, during the war between China and Japan, when the dikes were blown up and the Huang Ho consequently emptied into the Yellow Sea south of the Shantung Peninsula. After the dikes were repaired in 1947 the river again emptied into the Yellow Sea north of the peninsula.

The Huang Ho and its tributaries have a great hydroelectric potential, estimated at 23 gigawatts (GW). Two major hydroelectric power plants were constructed on the Huang Ho with the help of the USSR: the Liuchiahsia Hydroelectric Power Plant, near Lanchou (capacity, 1.1 GW); and the Sanmenhsia Hydroelectric Power Plant (capacity, 1.2 GW). The Huang Ho is navigable in some stretches, with a total navigable length of 790 km, mostly on the North China Plain. The river is used extensively for irrigation, primarily in its lower course and on the Hot’ao Plain. The densely populated basin of the Huang Ho is inhabited by more than 200 million people, according to a 1970 estimate. The cities of Lanchou, Yinch’uan, Paot’ou, Chengchou, K’aifeng, and Tsinan are situated on or near the Huang Ho.