抄録
Sea-dyke is sometimes constructed, so one part of bay has been enclosed. This kind of situation is also observed at Isahaya of Nagasaki, that is a big project of construction of sea-dyke and reclamation. In order to make clean the enclosed water bodies, integrated management based on rivers and watershed should also be emphasized. On this viewpoint, pollutant runoff analysis by means of the Digital Elevation Model (DEM) has been carried out, and how to make available the water environmental management has been discussed, considering the environmental changes around at the enclosed sea area.
Following to the purpose described above, in this paper, runoff rate of nitrogen from the watershed has been estimated, using the two-dimensional model of pollutant runoff by DEM. Even though parameter included in the model should be identified based on a lot of field data, it has been shown that proposed model might be useful for the prediction and control of non-point pollutant sources distributed over the watershed.
