These cold areas support most of the endangered or rare freshwater fishes, like some species of loaches, salmons, sculpins.
Streams, from the Mountain to the Sea
Dae-Min Kim
* See The Map of Administrative Divisions of South Korea
! To find names of waterways in the pictures you are looking at, please place your mouse cursor on a picture and wait a few seconds !
1. Mountain Streams - Upper river region
(mountain headwaters, creeks, highland riffles, mountain small rivers)
Compared to continental plain areas, South Korea supports a great number of mountains. Of the South Korean territory, at least 70% are dominated by forested mountains that contain an abundance of intrusive igneous rock.
Kangwon-do province and northern Gyeongsangbuk-do province together have mountain chains occupy elevations ranging from 1,600 to 5,500 feet.
Streams of these areas are lively waterways that roil and tumble over rock-strewn bottoms, forming waterfalls, gorges, and scenic pools. Uncommon insects, crayfishes, various amphibian including salamaders, highland frogs, toads, and watertoads are thriving here.
These cold areas support most of the endangered or rare freshwater fishes, like some species of loaches, salmons, sculpins.
2. Medium Rivers - Middle river region
(open and disturbed rivers, gravel riffles, sand riffles, drains)
Medium Rivers mean streams 25~50m wide during the average conditions. These rivers that flow through mountains, hills, towns, cities, or disturbed areas shows continuous riffles. Most of the Korean bodies of running water, excluding main bodies of river regarded as the major drainages, are this medium rivers. They have mainly complex environmental conditions, but herein, followings include remarkable stream conditions.
* Open and Disturbed : Any running water through the some medium-sized cities and industrial areas is suffering from pollution, damming, overabstraction, and low water level. All houses and buildings produce sewage. Harmful chemicals and wastes are often jettisoned into the streams through their illegal drains or underground pipes for rain water. Damming kicks out fishes that need riffles or gorges. It also has resulted in a collapse of many fish populations even in case where the dam has a fish-pass. Water abstraction and covering lands with what does not have water-permeability are making underground aquifer dried up. It has resulted in low river level and finally reducing fish stocks.
* The following map shows distribution of disturbed waterways in South Korea
* Gravel Riffles : Gravel riffles, a meander stream, tumble over rock and gravel-strewn buttom. It represents a typical lotic ecosystem and provides such nice habitats as riffles, pools, floatstone zones, and terraces. It has a few aquatic plants. Most of the Korean endemic freshwater fishes, very rare species, inhabit these gravel riffles.
Some riffles including Naerin River(KA), Inbuk River(KA), Song River(KA) are suffering from polluted sediments from highland-croplands in the upper river regions.
* The following map shows distribution of main gravel riffles in South Korea
* Sand Riffles : Sand riffle, a meander stream, is relatively quite runs of water over sand. It has afew aquatic plants and a little less aquatic insects than gravel riffles and large rivers, lakes, and ponds. Some of the Korean endemic and endangered species such as Iksookimia choii(미호종개) and Gobiobotia nakdongensis(흰수마자), live in these sand-bottomed riffles. If these sand riffles alerted by impoundment and damming, they will be disappeared.
* The following map shows distribution of sand riffles in South Korea
* Drains : Drains are deep drainage channels cut through low-lying region to turn marshlands into farmlands. They also include human-made waterways originally designed to use water to rice paddies, reclaimed lands along with waterways, and managed resorviors.
Because most of the drains tend to occur in lowland areas, the water tends to have a lot of plant nutrients and these produce lush weed and plankton growths. The fish species occupying these drains depends largely on species shared with eastern China where has lots of flattend areas with sluggish waters.
.jpg)
Drains close to cities had shallow margins on the side, usually richly vegetated, with weedbeds extending to the deep channel. However, today's revetment construction for flood control destroys shore vegetation. It has resulted in polluted water and reducing all fish, shellfish, crustacean, insect, amphibian, reptile, plant, bird, and mammal stocks.
3. Large Rivers - Lower river region
(alluvial rivers, gravel, sand or complex riffles)
Alluvial Rivers : The large alluvial rivers that flow through southeastern Korean Pen., Nakdong River, is well known. Thanks to the Gyeongsang Basin-slope that slopes gently down(from 5,000 feet to sea level) to the Korean Strait, South Sea, Nakdong River would be able to have the country's largest estuaries wetlands. Lower Nakdong River is sluggish and silty waterways rich in organic matter, with fishes and invertebrates living and breeding in and on the water. Bordering floodplain swamps, which could be over several miles wide, were regularly flooded especially in summer with silt-rich waters, creating ideal habitats for birds, crabs, and wetland plants.
In 1987, Nakdong Estuary Dam, the country's biggest estuary dam, was built. After that, swamps, tidal mudflats, and pools were reclaimed. The size of wetland is decreasing steadily, and now is no more than 2.5 miles. The abundant sea life and estuary life on upper dam areas had gone away. Although the dam has a fish pass, there have been a few fish species passing through this unfunctional path. Eulsukdo, an alluvial island, located at the center of Nakdong estuary area, was the biggest shelter for the migratory birds of whole world and it was designated as a "Natural Monument No.179" in 1966. However, environmental conditions around these areas have been alerted rapidly since the estuary dam was built.
These two pictures of Nakdong River Estuary are from the following web site:
http://konect.ktu.or.kr/wetlandtour
/anas_falcata/anas_falcata.htm
Han River, the country's largest and the second longest river following Nakdong, running through the capital of South Korea, Seoul, was also an alluvial river. Lower Han River had many islands called Hongdo, Nanjido, Yooldo, Tukseom, Samjeon, Burido, Seokdo, and Dangjangee, in wetlands areas along the shore. However, since 1982, beginning of The Han River Developments, almost all natural wetlands along the river and tiny creeks in Seoul Metropolitan Areas had been completely disappeared. The biggest islands in Han River main stream, Samjeon and Burido, have been forgotten from history after a massive development for Downtown Jamsil. Only a few people still know Seokchon Lake in the Lotte World Amusement Park was a deep pool in the main body of Han River and Nanjido was an actual island.
4. Lakes
(natural lakes and artifical lakes)
* Natural Lakes : South Korea has a few natural lakes since it has been a mountainous land. Natural lakes in South Korea tend to be relatively small, sluggish, and shallow. Most of these lakes have been reclaimed and turned into farmlands, industral fields, or even towns. Southeastern part of Korean Pen., Gyeongsangnam-do Province, has most of the Korean natural lakes, especially middle-lower and lower Nakdong River, lower Nam River-one of the tributaries to Nakdong- , and Changnyeong County near Nakdong River. They are more of wetlands than lakes and they play an important ecological role. These natural lakes' vegetations are luxuriant, and wildlife is abundant, including many species of insects, amphibians, reptiles, birds, and mammals. They also provide ideal habitats for migratory birds. Woopo(in Changnyeong County), the largest natural lake in South Korea, was designated as the nation's second Ramsar site. Woopo supports over 400 species of vertebrates including many endangered species and Natural Monuments.
Woopo Cyber Ecological Park : http://www.upo.or.kr/index.asp (These 2 pictures are from this web site)
Across the lower Nakdong River region, freshwater marshes border ponds, lakes, rivers, and streams. Their saturated soils and standing water support many herbaceous water loving plants, which can be either submergent or emergent.
Several decades ago, there were many marshes and natural lakes along lower Yeongsan River in Jeollanam-do Province and Dongjin River in Jeollabuk-do Province. Most of them are, however, reclaimed and turned into drains and farmlands.
* The following map shows distribution of natural lakes(including volcanic, e.g. Jeju Island) in South Korea
* Artificial Lakes : Many lakes in South Korea are human-made resorviors managed for hydroelectric power generation, flood control, and agricultural and industrial use. Dams, the biggest human-made resorviors, are built at narrow valley of the main streams in the mountainous areas. Most of the dam in South Korea are suffering from eutrophication. Soyang Dam, the 2nd largest dam in Asia and 5th in the world, was oligotrophic in 1970s through 1980s but nowadays also eutrophic.
5. Natural Ponds
(dumbeong)
* Dumbeong : Small ponds and spring-fed streams dot around the country, especially hill - rice paddy borders. South Koreans traditionally call them "Dumbeong". They provide clean water for rice paddies and small farmlands and ideal habitats for many aquatic insects, mountainous clams(Pisidium spp.), aquatic plants including a few insectivorous plants, and some freshwater fishes including Lefua costata, Misgurnus anguillicaudatus, Monopterus albus, Oryzias spp. Also they support breeding populations of many species of amphibians. 
6. Typical streams in the Jeju Island (e.g. Hyodon River)
Upper stream(mountain streams, waterfalls, and gorges) - Middle stream(underflows) - Lower stream(underflows) - Estuary(spring runs, gravel riffles, or gorges)
(See "Tidal Waterways" to find more!)
All contents are copyright © 2007 by Dae-Min Kim. All rights reserved.
