Geographical analysis of Heilongjiang river basin

Heilongjiang spans China, Russia and Mongolia, with a total length of 4,370 kilometers (with Hailaer River as the source), with a drainage area of 6,543.8+0.843 million square kilometers, ranking tenth in the world, and China's drainage area accounts for about 48% of the total drainage area. * * * There are about 200 tributaries, among which the larger ones are Songhua River, Wusuli River, Jieya River and Breya River. China's territory since ancient times.

Natural characteristics

zone

Heilongjiang begins at the intersection of Shileka River and Ergon River, 2824 kilometers (1755 miles) away from the estuary.

Shileka River rises at the confluence of Ingoda River in Siberia and Enong River in Mongolia, and is more than 547 kilometers (340 miles) inland. Ergon River originates from Inner Mongolia Autonomous Region of China, and is about 1 609 km (1 000 miles) from its confluence with Xileka River. The drainage area of this river system is about 1.855 million square kilometers (7 1.62 million square miles), including many rivers and lakes. The main tributaries are Zeya River, Breya River and Amgon River in Siberia, Songhua River in China and Wusuli River, the border river between eastern China and Siberia.

It is customary to divide Heilongjiang into upper, middle and lower reaches. The upper reaches start at the intersection of the Schleka and Ergon rivers and end at the Jieya estuary (located in the Siberian city of Hailanpo), with a total length of about 880 kilometers (550 miles). The middle reaches extend from the Jaya River to Khabarovsk, about 960 kilometers (600 miles) long. From Khabarovsk to Hekou, it is downstream, with a total length of about 960 kilometers.

Its upstream flows through the valley between the residual veins of Daxing 'anling covered by dense larch forest and the slopes covered by pine trees in Amazon Mountain. Near Albazino, Siberia, mountains separate and rivers enter the open plateau. The middle reaches flow into the Jaya-Bregeat River basin. The left slope of the valley is integrated with the plain, which is not easy to detect, while the right slope is adjacent to Xiaoxing 'anling. Then it crossed Xiaoxing 'anling along the narrow river like a canyon, and the depth and speed increased sharply. The lower reaches of the river pass between low and overflowing banks and enter a vast swamp. Waterways cut the ground, and lakes and ponds are dotted. The riverbed is multi-branched and the waterway becomes very wide.

Near Leninskoye, Siberia, the Songhua River, the largest tributary of Heilongjiang, has injected yellow sediment, and near Khabarovsk, the Wusuli River joins it. With the inflow of these flowing water, Heilongjiang flooded the flat moor in the tidal valley. The riverbed has become a maze of tributaries, inlets, old riverbeds, islands, sandbars and headlands. In Khabarovsk, Heilongjiang is only 370 kilometers (230 miles) from the coast of the Sea of Japan, but it flows 966 kilometers (600 miles) north and flows into the sea after being diverted by the Shihot Mountains.

climate

. The basin has a monsoon climate-winds from the mainland and the ocean change with the seasons. In winter, dry cold air from Siberia brings sunny and dry weather with strong frost. In summer, warm and humid sea breeze brings heavy rain, thus raising the water level of the basin and its main tributaries.

Autumn is warm and dry. 5438+ 10 The average temperature in June is -24℃(- 1 1 ℉) in the south and -33℃(-27 ℉) in the north. The average temperature in July in the south is 2 1℃(70 ℉), and in the north it is 18℃(64 ℉). The precipitation in the basin is uneven, and the coastal area is the largest, with an annual rainfall of 600? 900 mm (24? 36 inches).

hydrology

. Rivers are mainly replenished by monsoon rainfall in summer and autumn. Rain quickly flows into the river, forming 5? The flood period is June+10 in 5438. Its average flow rate is about 65,438+00,900 cubic meters per second (385,000 cubic feet per second). In winter, near Khabarovsk, the flow decreases to 148? 199 m3/s (5300? 7 100 cubic feet per second); 1897 recorded a maximum flow of over 39,200 cubic meters per second (1 400,000 cubic feet per second).

65438+1In late October, Heilongjiang began to freeze. Upstream freezing starts at 1 1, and downstream freezing ends at the second half of 1 1. The lower reaches of the river are thawed at the end of April and the upper reaches are thawed at the beginning of May. Ice jam often occurs in river bends, temporarily raising the water level as high as15m (50ft). This river brings about 20 million tons of sediment in 1 year.

plant

. Many parts of the basin are in the Taijialin vegetation belt. Especially in peat areas, larch is the main tree species, and there are some pines, spruces and firs in arid areas. In Daxing 'anling and Xiaoxing 'anling in the south, mixed forests of broad-leaved forest and broad-leaved coniferous forest can be seen, in which Mongolian oak, pine and larch are the main ones.

animal

. This basin is rich in fish. There are about 100 species of fish in the downstream, and about 60 species in the upstream, even surpassing European rivers such as Wawa River and Danube River. About 25 or 30 species have commercial value. A characteristic of Heilongjiang is that a large number of fish develop in the sea to avoid being hurt by the rapid change of river water level in summer.

-Baidu Encyclopedia