Sediment in Lake Soyang as Integrating Archive of Catchment Process and Potential Effect on Lake Water Quality
2 Department of Environmental Science, Kangwon National University, South Korea
3 Institute for Landscape Ecology, University of Muenster, Germany
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Abstract: Lake Soyang is the largest dam in South Korea and has an important meaning for the supply of supping drinking water. Lake Soyang is a warm monomictic. The water body is stratified by density difference during summer. During stratification oxygen depletion occurs in the hypolimnion through decomposition of organic matter. In these conditions, phosphate, N2O and CH4 can be released from sediment. Korea has a monsoon climate. In monsoon season with high rainfall, a large amount of terrestrial materials, including nutrients and organic matter flows into the lake from watershed. We hypothesize that the processes controlling the water quality in the lake are strongly related to the climate. During the monsoon period lake water quality is controlled by external processes. On the other hand, during the non-monsoon period, the lake is controlled by internal processing. The purpose of this study is to understand the extent to what catchment processes affect the nutrient dynamics in the Lake.
We hypothesize that materials released from the sediment, which are formed under anoxic condition and become distributed to the entire water body during the mixing period and can impact the water quality during dry season. In contrast, external input during the monsoon season with high loads of nutrients and carbon which mainly depend on catchment process will control internal sediment process and composition during the monsoon season.