Yangtze

The Yangtze River (English pronunciation: /ˈjæŋtsi/ or /ˈjɑːŋtsi/), known in China as the  Cháng Jiāng (literally: "Long River") or the  Yángzǐ Jiāng, is the longest river in Asia and the third-longest in the world. It flows for 6,300 kilometers (3,915 mi) from the glaciers on the Qinghai-Tibet Plateau in Qinghai eastward across southwest, central and eastern China before emptying into the East China Sea at Shanghai. The river is the longest in the world to flow entirely within one country. It drains one-fifth of the land area of the People's Republic of China (PRC) and its river basin is home to one-third of the country's population. The Yangtze is also one of the biggest rivers by discharge volume in the world.

The Yangtze River plays a large role in the history, culture and economy of China. The prosperous Yangtze River Delta generates as much as 20% of the PRC's GDP. The Yangtze River flows through a wide array of ecosystems and is itself habitat to several endemic and endangered species including the Chinese alligator, the finless porpoise, the Chinese paddlefish, the (possibly extinct) Yangtze River dolphin or baiji, and the Yangtze sturgeon. For thousands of years, the river has been used for water, irrigation, sanitation, transportation, industry, boundary-marking and war. The Three Gorges Dam on the Yangtze River is the largest hydro-electric power station in the world.

River

A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as stream, creek, brook, rivulet, and rill. There are no official definitions for the generic term river as applied to geographic features, although in some countries or communities a stream is defined by its size. Many names for small rivers are specific to geographic location; examples are "run" in some parts of the United States, "burn" in Scotland and northeast England, and "beck" in northern England. Sometimes a river is defined as being larger than a creek, but not always: the language is vague.

Rivers are part of the hydrological cycle. Water generally collects in a river from precipitation through a drainage basin from surface runoff and other sources such as groundwater recharge, springs, and the release of stored water in natural ice and snowpacks (e.g. from glaciers). Potamology is the scientific study of rivers while limnology is the study of inland waters in general.

Shanghai Yangtze River Tunnel and Bridge

The Shanghai Yangtze River Tunnel and Bridge is the collective name given to the bridge-tunnel complex across the south fork of the Yangtze River near the river mouth in Shanghai. The tunnel connects the Pudong District of Shanghai on the south bank of the river with Changxing Island, while the bridge connects Changxing Island with Chongming Island. In combination with the Chongqi Bridge (opened in December 2011), which connects Chongming Island to the north bank of the Yangtze, the bridge-tunnel complex forms the final crossing of the Yangtze before it empties into the East China Sea.

The bridge and tunnel were built from 2005 to 2009 at a cost of 12.6 billion yuan (US$1.84 billion), and opened on 31 October 2009. Their combined length is 25.5 km (15.8 mi), forming part of the G40 Shanghai–Xi'an Expressway.

Tunnel

The Shanghai Yangtze River Tunnel starts on the south bank of the Yangtze at Wuhaogou, Pudong and ends in the south of Changxing Island. It is 8.9 kilometres (5.5 mi) in length, and has two stacked levels. The upper level is for a motorway, and has three lanes in each direction, with a designed speed of 80 kilometres per hour (50 mph). The lower level is reserved for a future Shanghai Metro line, line 19.

China

China, officially the People's Republic of China (PRC), is a sovereign state in East Asia. It is the world's most populous country, with a population of over 1.35 billion. The PRC is a one-party state governed by the Communist Party, with its seat of government in the capital city of Beijing. It exercises jurisdiction over 22 provinces; five autonomous regions; four direct-controlled municipalities (Beijing, Tianjin, Shanghai and Chongqing); two mostly self-governing special administrative regions (Hong Kong and Macau); and claims sovereignty over Taiwan.

Covering approximately 9.6 million square kilometers, China is the world's second-largest country by land area, and either the third or fourth-largest by total area, depending on the method of measurement. China's landscape is vast and diverse, ranging from forest steppes and the Gobi and Taklamakan deserts in the arid north to subtropical forests in the wetter south. The Himalaya, Karakoram, Pamir and Tian Shan mountain ranges separate China from South and Central Asia. The Yangtze and Yellow Rivers, the third- and sixth-longest in the world, run from the Tibetan Plateau to the densely populated eastern seaboard. China's coastline along the Pacific Ocean is 14,500 kilometres (9,000 mi) long, and is bounded by the Bohai, Yellow, East and South China Seas.

Yangtze River Delta

The Yangtze River Delta, Yangtze Delta or YRD, also called Yangzi Jiang Delta, Changjiang Delta, River Chang Delta, Lake Tai Region or the Golden Triangle of the Yangtze, generally comprises the triangle-shaped territory of Wu-speaking Shanghai, southern Jiangsu province and northern Zhejiang province of China. The area lies at the heart of the region traditionally called Jiangnan (literally, "south of the Yangtze River"). The Yangtze River drains into the East China Sea. The urban build-up in the area has given rise what may be the largest concentration of adjacent metropolitan areas in the world. It covers an area of 99,600 square kilometres (38,500 sq mi) and is home to over 115 million people as of 2013, of which an estimated 83 million is urban. If based on the greater Yangtze River Delta zone, it has over 140 million people in this region. Having a fertile soil, the Yangtze River Delta abundantly produces grain, cotton, hemp and tea.

Early history

Since the fourth century, when the national capital was moved to Jiankang (present-day Nanjing) at the start of the Eastern Jin dynasty (AD 317–420), the Yangtze River Delta has been a major cultural, economic, and political centre of China. Hangzhou served as the Chinese capital during the Southern Song dynasty (1127–1279), and Nanjing was the early capital of the Ming dynasty (1368–1644) before the Yongle Emperor moved the capital to Beijing in 1421.