From the fast Nakdong river that shown a high degree of river use have had many back wetlands. Though back wetland such as Jeongyang wetland and Baksil wetland was developed in the flat river, most of the wetlands were cleared. The area of back wetland filled for several purposes of agricultural land, roads, embankments, land, industry was gradually decreasing. The wetland is supplied with flow rate through precipitation, surface water, ground water flow and influx with wetland. The loss of influx water is achieved through ground water, evaporation, and outflow of flow rate. The elements which compose wetland are hydrology, biology and abiotic. Though causal relationship among these factors is difficult to identify, the most essential elements in maintaining structure and function of wetlands are hydrological conditions of wetland, because these are related with inanimated elements.
The reduction of wetland area was not because natural causes but because human's economic activity. As a result flood control, soil stabilization, pollution control, hydrological stability and nutrient cycling were diminished. If flow of flood was inhibited, damage could occur in the region near because of high flood level and fast flow. Wetland which is the world's most important water resources, from the fast, has been managed with several methods according to purpose human uses. Efficient management of wetlands is needed. Though the water resources management of hydraulics and hydrology is existing many difficulties by using the wetland, effective methods should be prepared for the reduction of flood, water-purity control, soil stability, hydrology and stability because of difficult situation for systematic management of wetlands. The scientific assessment data of wetland is needed for preservation of wetlands and development sustainable.