And the border. Han ma also said water, tang said the yalu river in the beginning, because of the color dark green such as duck head. From the changbai mountain peaks mount paektu located at an altitude of 2300 meters. Through the mountains, steep slope flow hurry, GuKuan 50-150 meters. Below middle reaches the river, to the southwest, the slope is slow, GuKuan 200 ~ 2000 meters. Under the downstream from the water abundance, valley open expansion, low mountain hills and plains of narrow, on both sides of jiangxin sandbars. The river on the island of nearly 200, with an beach is the largest. Dandong Jiang Kuan 5 kilometers, near the stream to the points donggou two into the yellow sea, 795 km, the basin area of 6.3788 square kilometers, China accounts for about half. Water system developed, a tributary of the construction control, and more main stream into rectangular. North main tributaries have HunJiang, PuShiHe, Ai river, south main tributaries have XuChuanJiang, long jin jiang, bald LuJiang, loyal boundless hone, etc. HunJiang 415 kilometers long, the catchment area of 1.14 square kilometers, the valley deep 600 meters, is a typical mountain meander. The yalu river flows through the temperate humid regions, the annual rainfall of 870 mm, from upstream to downstream, and increasing 70% concentration of 6 ~ 9 months. Average flow 1040 cubic meters per second, annual runoff is 32.76 billion cubic meters. Every year spring flood are formed when the snow melting ice. Often appear during dry 5 ~ 6 months. Summer in August 7 to sin, and maximum flow generally 15 ~ 25 times of the average annual flow. Climate cool wet whole basin, the distribution, which is mainly composed of Korean pine, maple, birch needle broadleaf mixed forest, downstream oak forest. There are many wild animals and plants. Small river sediment concentration and sediment discharge. The yalu river flows through the changbai mountain, steep narrow valley, slope, 2.3 million kw hydropower resources. Good cansu more dam site. Abundant water power station is China in the first large scale power station joint venture, in addition to yunfeng, devoted, HuiLongShan and taipingshao is given priority to with power generation, combined with the flood control, irrigation, shipping and other large and medium-sized comprehensive water conservancy project. Ann, estuaries and dandong have railway highway bridge connection on both sides, for China and the DPRK traffic arteries, among them with dandong - sinuiju bridge (sino-korean friendship bridge), the most spectacular. Yalu river because of water shallow freezing winter, aggregate beach water more urgent, shipping limited, under water abundant reservoir navigable, the biggest port of dandong. The yalu river in 1988 was approved as national key scenic spot.