Application of groundwater modeling to predict the effectiveness of various peat dome restoration methods in Pulang Pisau District, Central Kalimantan Province

Abstract

A number of Indonesian Peat Hydrological Units (Kesatuan Hidrologis Gambut/KHG) have undergone severe degradation and require an effective restoration measure to increase their ecological, social, and economic function. A peat dome located in Garung village, Pulang Pisau District, Central Kalimantan Province, was selected in this research. It aimed to apply the mathematical modeling to predict the effect of various restoration methods on the sustainability of ecological functions of peak dome in this area and reveal the advantage and disadvantages of each specified method. The groundwater model was performed in this research to simulate the influence of four different restoration methods on the groundwater level of the peak dome. The water budget and the hydraulic conductivity of groundwater assigned in the modeling were derived from the previous research done in the other village within the same Peat Hydrological Units. Meanwhile, the soil property data and the other data related to groundwater and canal properties were obtained from the field measurement at the location during the rainy season. The result of modeling indicates that the restoration method employing a combination of canal backfilling and revegetation affects the most effectively the rising groundwater level of peat dome in the model domain, followed by the individual canal backfilling and canal blocking methods, respectively. The modeling approach enables us to prove the outcome of each applied restoration method toward the area of peak dome having groundwater level lower than 40 cm. In order to be able to apply this model in the other peatland area, a model validation utilizing the field measurement of hydraulic conductivity, groundwater level, and the canal water level is necessary to be carried out throughout the year, particularly during the dry season.