Formation of Cheorwon Plains and Ecological Transition

Saemtong belongs to a basaltic lava land, where a fountainhead gushes forth ukewarm water and creates a swampland that does not freeze in winter, thus offering a natural condition favorable to the habitation of wild fowl, and it has been designated as Natural Monument No. 245 and is preserved as a habitat for migratory birds. The region of Cheorwon plains belongs administratively to Woljeong-ri and Daema-ri, Cheorwon Township, and Hagal-ri, Dongsong Township, Cheorwon County, Gangwon-do Province, and occupies the area between the latitudes of 38° 15' N and 38° 18' N and the longitudes of 127° 09' E and 127° 18' E.

Parts of Dongsong Township and Cheorwon Township located in a basin formed along Sangnyu-cheon, Yeokgok-cheon and Daegyo-cheon streams, all tributaries to Imjin-gang and Hantan-gang Rivers, are relatively flat and have hilly lands 200 to 300 meters above sea level. The area has a river system consisting of large and small streams such as Yeokgok-cheon and Sangnyu-cheon, along which agricultural flatlands are cultivated with an abundance of agricultural water resources. There are man-made reservoirs for agricultural purposes, including Hagal Reservoir (9.5 ha), Gangsan Reservoir (74.9 ha) and Sanmyeong Lake (79.4 ha), and, despite numerous hillocks of more or less than 300 meters' height, including Baengma-san (395 m), Somi-san (362 m), Gunnyang-bong (320 m), Sapsong-bong (219 m) and other low-lying hills, the whole area is relatively flat and provides favorable conditions for the habitation of winter birds such as red-crowned cranes, wild geese and ducks. Cheontong-ri (alias known as Saemtong), Cheorwon Township, is now designated as Natural Monument No. 245 for the habitation of migratory birds. This region is a basaltic lava land created in the past by a volcanic eruption in a hilly area, and, thanks to its fountainhead gushing forth lukewarm spring water (15 degrees Centigrade even in winter), this place is frequented by people for water supply.

Consequently, a wide variety of cranes and other species flock here due to its naturally attractive conditions; as it is a civilian control zone where unauthorized persons are not allowed to enter, its natural advantages are well kept. The Cheorwon plains have been abandoned to nature from the ceasefire in 1953 till the 1970s and the military buffer zone south of the Ceasefire Line, together with the neighboring rice paddies and farms, has been greatly transformed by meadows and shrubbery; the area north of the Cheorwon plains has now a mass of grasslands harboring swamplands.

Ever since the 1970s, red-crowned cranes, white-naped cranes and other protected species visit here regularly to spend winter seasons and during the passage periods of spring and late autumn, a massive group of white-naped cranes fly over this area. In Cheorwon County, though 70 percent of its area consists of mountains, very few mountains are 1,000 meters above sea level; under the geographical influence of Chuga-ryeong Gorge and Gwangju-sanmaek Mountains, it has flat hills and plains which, while belonging to the temperate zone of the Korean peninsula in terms of climactic conditions, is also near the cold latitudes in the north so that animals and plants inhabiting both temperate and cold climates populate the place. Though this region had been covered with plush forestry just before the Korean War with a lot of animals inhabiting there, it became a battleground widely known as Cheor-ui-samgak-jidae (Triangular Zone of Iron) where deforestation and gunshots made it no longer possible for animals to live. However, now that over 50 years have passed since the ceasefire, the whole area thrives again with thick forests and, in the zone inside the Civilian Control Line where private individuals are prohibited from entering, a wide variety of trees and grasses have grown in primitive forms, furnishing a safe haven for all kinds of animals.

Though rare alpine animals and plants are very few in this district, because, while incorporated as part of the Civilian Control Zone together with Yanggu, Inje, Goseong etc., it is relatively devoid of rugged and precipitous mountains and ranges, it represents the greatest paradise for migratory birds' habitation. Cheorwon County, located right in the middle of the Korean peninsula, nestles in the northernmost plains in Gangwon-do Province west of Taebaek Mountains against the backdrop of Gwangju-sanmaek Mountains ranging southwest from Geumgang-san (Diamond Mountain) in Taebaek Mountains to Gyeonggi-do Province and facing Chugaryeong Gorge ranging from Seoul to Wonsan in the west.

Of the whole length of the 155-mile (or 249.4-kilometer) Armistice Line drawn in the middle of the Korean peninsula, 28.1 %, or 43.6 miles (70.2 Km) pass through Cheorwon. That part of the Armistice Line starts in the east from the boundary between Bangsan-myeon, Yanggu County, and Imnam-myeon, Cheorwon County, and passes westward through Sudong-ri in Imnam-myeon; Sehyeon-ri in Wondong-myeon; Jukdae-ri of Wonnam-myeon; Bangtong-ri and Gwangsam-ri in Geundong-myeon; Geumyok-ri, Sangcheong-ri and Yosu-ri of Geunbuk-myeon; Hyangyeon-ri (Heukyok-dong) in Nam-myeon, Pyeonggang County; Junggang-ri, Gangsan-ri and Hongwon-ri of Buk-myeon; Sanmyeong-ri, Gayeon-ri and Igil-ri in Mujang-myeon. Major birds of passage observed include such winter birds as red-crowned cranes, white-naped cranes, wild gees and ducks.