Hydrodynamic effect of deforestation on the Jilmoe-neup, a Ramsar Wetland in Korea

Abstract

This study evaluates the effect of deforestation on wetlands by hydrodynamic modeling. CAESAR-LISFLOOD is used in this study for the hydrodynamic modeling, which adopts the finite element method to solve the SaintVenant equation and Manning's equation for kinematic wave flow. This study focuses on Jilmoe-neup wetland, a Ramsar wetland, in Korea. Although Jilmoe-neup wetland was once located in a thick forest, most trees were removed in the 1970s to expand the pasture. The simulation result shows that a reservoir effect is crucial to form the wetland, which is mainly due to the narrow and deep drainage channel at the outlet of the wetland. On the other hand, deforestation is found to have significantly changed the hydrodynamic characteristics of Jilmoe-neup wetland. In particular, increased flow velocity is found to induce hillslope erosion and sedimentation in the wetland area. More sand is likely to flow into the wetland, which must also hinder the formation of peat layers. Finally, with a moderate restoration of forest, it seems possible to recover and maintain Jilmoe-neup wetland along with the current peat layer.