The Reconstructure of Paleo-Hydrography by Diatom Analysis in Moat No. 1 of Wolseong, Kyeongju

To reconstucte the paleo-hydrological environment of the sediment in the Wolseong 1st moat, diatom analysis and DAIpo (Diatom Assemblage Index to Organic Pollution) were used. The four diatom zones identified with the diatom assemblages corresponding to the period of the Pit moat being DI, DII, and DIII. Relative pollution was highest in period DII, followed by an improvement in pollution in period DIII. This corresponds to a decrease in flow velocity and the second lowest water depth of all periods. Therefore, it is likely that there was a water quality management of the moat contaminated by human activities. The DIV period corresponds to the time of the stone-structured moat, and pollution levels tend to increase again as the moat decreases in width. The subsequent improvement in water quality is likely due to artificial remediation of the increased pollution during the construction of the initial stone-structured moat.