국내 하천 형상을 반영한 SWAT 모형 내 하천폭 및 홍수터폭 산정 회귀식 도출

초록

In this study, the channel and floodplain widths are indirectly measured for three different watersheds using satellite images to reflect the shape ofKorean channels in the Soil and Water Assessment Tool (SWAT) model. For measuring the channel and floodplain widths, multiple satellite imageswere referred to ensure the widest width of certain points. In the single channel, the widths at the multiple points were measured. Based on themeasured data, the regression equations were derived to estimate the channel and floodplain widths according to watershed areas. Applying thesedeveloped equations, this study evaluated the effect of the change of channel and floodplain widths on the SWAT simulation by comparing to themeasured streamflow data. The developed equations estimated larger channel width and smaller floodplain compared with those calculated in the currentSWAT model. As shown in the results, there was no considerable changes in the predicted streamflow using the current and developed equations. However, the flow velocity and channel depth calculated from the developed equations were smaller than those of the current equations. The differenceswere caused by the effect of different channel geometries used for calculating the hydraulic characteristics. The channel geometries also affected thewater quality simulation in channels because the hydraulic characteristics calculated by the channel geometries are directly related to the water qualitysimulation. Therefore, application of the river cross-sectional regression equation reflecting the domestic stream shape is necessary for accurate waterquantity / quality and water ecosystem simulation using hydrological model.

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