Search

Peatlands rewetting for hydrological restoration plays an important role in fire prevention and peatland restoration of degraded peatland. One of the methods for the rewetting is canal blocking. The impact of canal blocking for peatland rewetting is further analyzed in this research. This study focused in Pulau Tebing Tinggi peatland hydrological unit (PHU), which is located in Kepulauan Meranti Regency, Riau Province. To analysis the rewetting impact, 15 dipwells were installed with the distance of 1 m, 51 m, 101 m, 201 and 301 m from the canal for each transect of the three transects. A transect was set in the downstream and two transects were set in the upstream of canal block. The ground water level (GWL) in the 15 dipwells was recorded using water-loggers for one year. This research found that canal blocking has a good effect on maintaining groundwater levels and keeping peatlands in always wet or humid conditions up to a distance of 201 m perpendicular to the canal if the rise in water level in the canal due to canal blocking is more than 0.6 m. It is able to maintain the ground water depth in peatlands around 0.4 m, where the peatlands become low risk to the fire, emission rates and subsidence.

Changes in land use of tropical peat will lead to the release of carbon (C) on the condition that initially stabilized, and resulting in land subsidence. Peatland clearance which is preceded by the construction of the canals will cause the ground water table in peatlands fell. Along with that, the subsidence occurs, which at the beginning of peatland reclamation rate of decline very fast and gradually slow down over time with reduction of organic materials that decompose or burn. Therefore, knowledge of the rate of subsidence is very important to plan drainage and optimal use of peat land in order to preserve the peat. The method or scientific approach used is the assessment directly, include: measurement of the location of groundwater levels, land subsidence at various existing condition of land in different locations, peat soil sampling and calculation with the empirical formula. The calculation of land subsidence using average data groundwater levels during the dry season, in addition to the types of land cover took into account as well. This paper presented the results of the analysis of land subsidence and the projected decline in the next 50 years peatlands in Sei Ahaz, Kapuas, Central Kalimantan and Sungai Buluh, Tanjung Jabung, Jambi and comparative results between the two locations. The implications of this study indicate that the regulation of groundwater levels will control land subsidence.