Water Balance of Various Peatland Typologies in Central Kalimantan

Abstract

The water balance of a peatland area is important information for the management of water resources. This study aims to predict the water balance in several typologies of peatlands in Central Kalimantan, Indonesia. The method used is a Thornthwaite Mather water balance analysis model. This method is based on input data in monthly rainfall and temperature in 2019 at the study locations. The output of this method is predicted monthly runoff. The method analyzes the evapotranspiration process and the soil’s ability to hold water. There are four types of peatlands analyzed: (1) primary forest (Mangkok), (2) secondary forest (Forest Area with Special Purpose/FASP Tumbang Nusa), (3) Shrubs (RePeat), and (4) open area. Research results show that the annual rainfall in Mangkok is 2,555 mm/year, with the actual evapotranspiration of 1,594 mm/year, yield the annual water of 653 mm/year. In the FASP Tumbang Nusa, the annual rainfall is 2,570 mm/year, with the actual evapotranspiration of 1,592 mm/year, yield the annual water of 648 mm/year. In the RePeat location, the annual rainfall is 2,550 mm/year, with the actual evapotranspiration of 1,580 mm/year, yield the annual water of 549 mm/year. The open area location (Kahayan) has an annual rainfall input of 2,375 mm/year, then the actual evapotranspiration is 1,598.98 mm/year, while the annual water yield is 823.08 mm / year. The water deficit in the four study locations occurred from July to September, while the water surplus occurred from January to June and continued from October to December. August to November is the month with the lowest water yield in the four study locations.