A river is a natural watercourse, usually freshwater, flowing toward an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names including stream, creek, brook, rivulet, tributary and rill; there is no general rule that defines what can be called a river, although in some countries or communities a stream may be defined by its size. There are number of rivers in the world but most of them these days are polluted. But still in this world of pollution and contamination, there are few rivers which are completely clean. So here is a list of five cleanest rivers of the world. Have a look!
1. River Thames
The River Thames is the cleanest river in the world that flows through a major city. This is a major feat considering that 50 years ago the river was so polluted that it was declared biologically dead. From 1830 to 1860 tens of thousands of people died of cholera as a result of the pollution in the Thames. Sewage was being discharged directly into the Thames. It was decided that ‘Treatment plants’ should be built to clean the water from the Thames before it was pumped to homes. The treatment plants also cleaned dirty water from homes before it went back into the Thames. Not only did the people’s health improve, but also the water in the Thames became cleaner. In the 1960s new laws were made to stop factories letting their dirty water go into the river. Today more than half of London’s sewage sludge is sold in pellet form as fertilizer for agricultural use.
2. Tara (Drina)
The Tara river is known for its cleanest water. The Tara is a river in Montenegro and Bosnia and Herzegovina. It emerges from the confluence of the Opasnica and VeruÅ¡a Rivers in the Prokletije mountain, part of Dinaric Alps of Montenegro. The total length is 144 km, of which 110 km are in Montenegro, while the final 34 km are in Bosnia and Herzegovina; it also forms the border between the two countries in several places. The Tara flows from south to north, then north-west and converges with the Piva at the Bosnia and Herzegovina and Montenegro border between the villages of Å Äepan Polje (Montenegro) and Hum (Bosnia and Herzegovina) to form the Drina river.
3. St. Croix River
The St. Croix River is a tributary of the Mississippi River, approximately 164 miles (264 km) long, in the U.S. states of Wisconsin and Minnesota. The lower 125 miles (201 km) of the river form the border between Wisconsin and Minnesota. The river is a National Scenic Riverway under the protection of the National Park Service. A hydroelectric plant at St. Croix Falls supplies power to the Minneapolis-St. Paul metropolitan area. The St. Croix River rises in the northwestern corner of Wisconsin, out of Upper St. Croix Lake in Douglas County, near Solon Springs, approximately 20 miles (32 km) south of Lake Superior. It flows south to Gordon, then southwest. It is joined by the Namekagon River in northern Burnett County, where it becomes significantly wider. A few miles downstream the St. Croix meets the boundary between Minnesota and Wisconsin, which it demarcates for another 130 miles (210 km) until its confluence with the Mississippi River.
4. Torne River
The Torne River is a river in northern Sweden and Finland. Approximately half of the river’s length is a part of the border between these two countries. It rises at Lake Torne near the border with Norway and flows generally southeast for a distance of 522 kilometers (324 mi) into the Gulf of Bothnia. It is the largest river in Norrbotten both by length and by watershed area and is also one of the cleanest rivers in the world. The source of the Torne River is generally considered to be Lake Torne near the border with Norway. Lake Torne is fed by NjuoraÃ¤tno and KÃ¥ppasjÃ¥kka in the west. Beyond the lake, the Torne rivers flows unhindered by any concentrations of human inhabitants until the village of Kurravaara, around 12 kilometres (7 mi) northeast of Kiruna.
5. Li River (Guangxi)
The Li River originates in the Mao’er Mountains in Xing’an County and flows in the general southern direction through Guilin, Yangshuo and Pingle. In Pingle the Li River merges with two other streams, and continues south as the Gui River, which falls into the Xi Jiang, the western tributary of the Pearl River, in Wuzhou. The 437-kilometer course of the Li and Gui Rivers is flanked by green hills. Cormorant fishing is often associated with the Lijiang (see bird intelligence). Its unusual karst topography hillsides have often been compared to those at Halong Bay, Vietnam.