Sand is the simplest capping material proposed to date to contain phosphorus in sediment in situ. This research was carried out to understand the role of sand capping in the speciation and release of phosphorus from sediment. Clean sand was laid on sediment sampled at a eutrophicated lake in one dimensional columns with different capping thicknesses. It could be understood from the experiments that sand capping with a thickness of less than 50 mm reduced the phosphorus concentration by over 85% and was effective in reducing the amount of phosphorus released from the sediment. Thicker sand capping reduces the amount of phosphorus released from the sediment to a greater extent. Since sand capping retards the release of phosphorus from the sediment, a higher fraction of non-apatite P (NA-P) was able to be converted into the less soluble Apatite-P (AP).

For effective improvement of water quality in Seokmun reservoir, this study implemented various analyses including the tributary water quality and flowrate monitoring, contamination of sediment, investigation of pollution source, selection of priority management target tributary by stream grouping method. The COD concentration of the majority of tributaries in Seokmun reservoir watershed was relatively higher than BOD concentration. The concentration of water pollutants regardless of water quality parameters in Yeokcheon, Dangjincheon, Sigokcheon, Baekseokcheon, small stream in Jinkwanri and Janghangri were higher than the other tributaries. The pollution sources in the Seokmun reservoir watershed were mostly distributed in the population, livestock, and industry. The pollutants, which located in Yeokcheon, Dangjincheon, Baekseokcheon, and small stream in Janghangri selected as priority management target tributary, should be preferentially reduced for improving the water quality in Seokmun reservoir. As the evaluation results of water quality in Seokmun reservoir for the effect of water quality improvement according to various scenarios using water quality model, it was found that the water quality in Seokmun reservoir due to the construction of a wastewater treatment plant for management of pollutants in the watershed would be satisfied the class V of water environment standard in reservoir.

No abstract