REWETTING OF DEGRADED TROPICAL PEATLAND BY CANAL BLOCKING TECHNIQUE IN SEBANGAU NATIONAL PARK, CENTRAL KALIMANTAN, INDONESIA

摘要

Sebangau National Park is a tropical peat swamp forest previously used for logging activities (illegal and legal) between the 1970s until 2006. Logging activities created the canal networks used for transportation of logs and led to over-drainage in peatland. Two-hundred and seventy three canals were recorded over a total length of 673.486 km in nine locations at the Sebangau National Park. Restoration of degraded peatland area started by rewetting peatland using canal blocking technique in which the dam increases the water table level. This technique was implemented in the Bulan River, Katingan Catchment, southwest of Sebangau National Park. The location of canal blocking were determined using canal elevation, estimated every 25 cm by combining field survey and imagery data from digital terrain model. Final decision on canal blocking was reached through compromised discussions with the villagers in order for them to understand the aims of canal blocking and to come to an agreement with the beneficiaries of non-timber forest products and fisheries around the affected area. The canal blocking have resulted in 645 dams being built along the 92 canals with total length measuring 226 km. Measurement impacts of canal blocking were monitored by monthly data of surface water level (swl) in 16 locations and groundwater level (gwl) in 112 pipes for the period from June 2013 to July 2015. The analysis shows that canal blocking effect is significantly positively correlated with water level controlled by rainfall (p < 0.05). The positive impact after the canal blocking is on the increase of swl (mean of swl: before = -33.966 cm, after = -26.099 cm; rainfall = 191.0398 mm) and gwl (mean of gwl: before = -19.442 cm, after = -11.925 cm; rainfall = 191.0398 mm). Other efforts that should be done to promote restoration include peat fire prevention, reforestation and community involvement.