SIMULATION OF CO2 EMISSION AND LAND SUBSIDENCE IN RECLAIMED TIDAL PEAT SWAMP IN BERBAK DELTA, JAMBI-INDONESIA
Keywords:peat land, CO2 and subsidence simulation, drainage
Environmental impacts of agricultural drainage in a reclaimed tidal peat swamp in Jambi, Indonesia are investigated. A 3-Dimensional (x,y,t) model is developed to simulate the drainage-driven CO2 emission and land subsidence. The initial condition of water table was obtained from a coupled groundwatercanal model. In the first simulation, several scenarios of drainage width ranged from 0.1 m to 1.5 m are analyzed. Model output for 100-year simulation shows that the 0.8 m drainage (e.g. real condition) releases about 794,000 ton of CO2 or equal to IDR 61.2 billion. In addition, the 0.8 m drainage also causes land subsidence of about 52 cm, and reduces the drainable area up to 62.3%. Note that the impacts are robustly lower (higher) when shallower (deeper) drainage depths are applied. The second simulation uses drainages that are appropriate for particular plants and analyze the selling-profit/emission-loss ratio. Among 16
plantation scenarios, it is found that the highest CO2 emission and land subsidence is caused by industrial forest (e.g., oil palm). Therefore, it reduces the profit significantly. On the other hand, the food crops, such as paddy field, have higher profit/loss ratios than the industrial forests.