The effectiveness of canal blocking for hydrological restoration in tropical peatland

Abstract

The Peatland Restoration Agency of the Republic of Indonesia (BRG-RI), an agency that is mandated to restore 2 million hectares of degraded peatland by 2020, has developed a 3-R approach towards tackling the problem based on the program of rewetting, revegetation, and revitalization of livelihood for the peatlands restoration in Indonesia. The Rewetting program that aims to rehabilitate hydrologically a peatland to a near natural state is carried out by canal blocking, canal backfilling, and construction of deep wells. To know the progress of the restoration activities by BRG, it is very important to understand the effectiveness of canal blocking on rewetting of the tropical peatland. The effectiveness of canal blocking was investigated through the monitoring of groundwater level (GWL) fluctuation around the canal block. This study was carried out at a canal block that is located at the peatland of Sungai Tohor Village, Kepulauan Meranti Regency, Riau Province. For monitoring of GWL fluctuation as the impact of canal blocking, five dipwells were set at the peatland that are perpendicular to the canal with the distance of 20 m, 70 m, 120 m, 170 m, and 220 m respectively. The results of this study show that the impact of canal blocking could raise the water table in the peatland at the radius of about 170 m from the canal. The radius impact of the re-wetting might be bigger or smaller, that strongly depends on the hydrotopography situation of the area.