インドネシア・中央カリマンタン熱帯泥炭湿地林における地下水流動解析

Abstract

In 1980s, 'Mega Rice Project' for the expanded agricultural production was planned in Indonesia, and so many drainage canals have been constructed for irrigation and drainage of tropical swamp peatland in Kalimantan Island. But it brought the groundwater level drawdown in the drained swamp peatland, so that it caused a huge amount of carbon dioxide emission by forest fires and soil degradations. In order to conserve the groundwater level by the canal water level management, the canal backfilling and/or gate construction should be discussed in the civil engineering viewpoint. In this study, two-dimensional groundwater flow model related with the river flow condition and the land surface process was integrated for quantitative evaluation of the effect of canal repair management. Simulation results of groundwater level drawdown by the canal construction suggest the conservation of the hydrological environment and the CO2 emission reduction by canal management in the tropical swamp peatland.