Compared with the size of territory, Korea has many rivers and streams and a dense river network.
There are thousands of small and medium rivers. The Amnok, Tuman, Taedong, Raktong and Han rivers are called five long rivers in Korea and those plus the Chongchon, Ryesong, Kum, Somjin and Yongsan rivers are called ten long rivers. The Amnok (803km) is the longest in Korea, having the widest area of basin (64 740 sq km).
There are over 100 natural lakes and 1 700 artificial lakes. The latter is used for irrigation, power generation, flood control, industrial and urban water supply, transport, fish farming, landscaping and so on.
Noted man-made lakes are Suphung, Jangjin and Thaechon lakes for power generation and Unpha, Sohung, Yonphung, Thaesong and Paengma lakes for irrigation and Lake Kumsong for flood control.
There are many mineral springs. North Hamgyong and South Hwanghae provinces have lots of hot spas, whereas North Phyongan and Jagang provinces are blessed with mineral water.
There are more than one hundred mineral springs like famous spas including Paektu, Yangdok, Talchon, Kyongsong and Onpho spas and Kangso, Okryu, Myohyangsan, Sogwangsa and Yodok mineral water.
They all have bicarbonates as main component, of which spas have sodium bicarbonate as main component and mineral water has calcium bicarbonate as main component.
Onpho Spa is located in Onpho-ri, Kyongsong County, North Hamgyong Province. It was discovered about 500 years ago. Thousands of tons of water gush out of tens of spring outlets a day. The water temperature is 57°C.
It is efficacious for the prevention and treatment of neuralgia, neuritis, arthritis, hypertension, dermatosis and chronic eczema.
Kangso Mineral Water
The spring is situated in Yaksu-ri, Kangso District, Nampho. The water temperature is 7-15°C. It is highly efficacious for curing mouth disorders and gastric and duodenal ulcer and other chronic troubles such as gastritis, hepatitis, pyelitis, cystitis, enteritis and colitis.
As the production bases have been expanded and the quantity has increased, the mineral water is supplied to Pyongyang and local areas.
Sindok Spring Water
The spring is in Onchon County, Nampho, and is widely known to the world. Local people live for over 100 years.