Effectiveness Analysis of Canal Blocking in Sub-peatland Hydrological Unit 5 and 6 Kahayan Sebangau, Central Kalimantan, Indonesia

Abstract

The height of canal blocking has a significant influence on re-wetting peatland, depending on the canal’s distance. An effective canal in good condition has to raise the groundwater table to -0.4 m below ground level according to the Indonesian Ministry of Environment and Forestry (MENLHK). The effectiveness of different canal blockings was modeled by Freewat software with variation of canal distance (200 m, 250 m, 300 m, 350 m, and 400 m) and blocking height (0.2 m, 0.3 m, 0.4 m, 0.5 m, 0.6 m). This simulation was carried out using recharge and evapotranspiration data covering 20 years. The input of the conductivity value was done using 50 m/day according to the calibration. From the modeling, 0.6 m high canal blockings give a satisfactory result at every canal distance. The study took place during the annual dry season, when recharge was almost zero and average evapotranspiration was 6 mm/day. Adjusting the canal blocking to a maximum of 0.6 m and the canal distance to 400 m, the groundwater table slowly rose 0.38 m and it took 30 days to reach full-re-wetting capacity. This study revealed that the effectiveness of canal blocking is directly related to evapotranspiration and recharge, which has a positive correlation with the groundwater rise and the re-wetting period.

Restoration of Degraded Tropical Peatland in Indonesia: A Review

“…Canals that are constructed parallel to contour lines do not require as many dams. Dam construction needs to account for the difference between the height of water in the canal and the peat surface (Ritzema et al 2014), with simulation modelling suggesting that canal blocking can be most effective when the vertical distance between dams is 0.6 m [112]. This study also revealed that the effectiveness of canal blocking at maintaining the groundwater level is directly related to the balance between evapotranspiration and recharge, and the length of the drought period.…”

Performance assessment of existing canal-blocking in restoration management of peatland conservation

“…In the Block-C ex PLG on the thick peatland, further development has to be prevented, has to be carried out the channel closure and available drain, and the groundwater surface will increase. The analysis of hydrology that is carried out can be shown as follows [13], [14]: 1. Now, the edge of the channel is 1 metre or > under a level of peat dome.…”

“…The main principle for decreasing and preventing the fire and smog in the peatland is hydrology restoration action [1]. It is based on the fact that as a result of too much drainage canal construction when the opening of one million ha area (PLG), mainly in the work area of block-C, has caused peatland damage which impacts the local economy at a time supporting the happening of global GRK emission.…”

Effects of climate anomaly on rainfall, groundwater depth, and soil moisture on peatlands in South Sumatra, Indonesia

“…1). The canal system drains the water from peatlands and thus affect the groundwater near the canals, so that the groundwater level at the OKI-1 becomes lower (Ivan et al 2020;Lu et al 2021;Suryadi et al 2021;Sutikno et al 2020).…”