actively applied the strengths of the examples of peat management by other companies and improved the technologies by conducting a thorough scientific examination,
while comprehensively eliminating the weaknesses. Finally, WSL-MTI have
become familiar with proposing responsible peatland management in Indonesia,
taking into consideration the hydrology of the peat ecosystem, mainly the peat dome.
The GWL should be kept 0.4 m below the soil surface as stated in the government
regulations (ex. P.71/2014; P.57/2016) regarding the utilization of peatlands for
palm oil and pulpwood production (Indonesian Government Regulation 2016).
Although opinions that differed regarding the regulation of 0.4 m, WSL-MTI
considered 0.4 m to be the most preferred standard to avoid peat fires based on
observations of the relationship between the GWL and soil moisture content during
the dry season. Acacia trees also grow normally, as long as there are no major
fluctuations in the GWL. Conversely, drainage-based water management has only a
drainage function and no mechanism to control the water level, so the GWL cannot
be kept constant throughout the year, which sometimes leads to large fluctuations in
the GWL with the changing climate. Consequently, a constant standard for the GWL
regulated by the government has prevented good growth of acacia trees.
The water is sustained in peat by Intermolecular Force (van der Waals force). As
the intermolecular force of peat and water is not strong enough, water can easily be
released from peat when canals and ponds are made in peatland. In a degraded
peatland, a well-designed canal system is required to control GWL, distribute water
to the whole area, and plant trees for reforestation. Two types of canals are
recommended in the WSL-MTI plot design (Fig. 3.3). The main canal with a
width of 10–12 m and depth of 3 m, and branch canals with a width of 6–8 m and
depth of 3 m. The main canal should be constructed from the lower to the near upper
area such as the backbone in an animal body. The main canal should be completely
blocked by a peat dam every 0.5–0.6 m in elevation to prevent water from flowing
down to the lower side due to gravity. In the case of unpredictable heavy rain,
spillways, which are constructed at the same point of the peat dam, play an essential
role in discharging excess water from the upper to the lower side. Without spillways,
the planted area would be flooded by excessive water and severely damaged by an
extreme water level. It should be noticed that the spillway has a function of
controlling the flow volume and the speed of the excess water to prevent flooding
in the lower plantation area. The specifications of the spillway should be calculated
by an estimation of excess water volume and expected flow speed in relation to
maximum rainfall predicted.
The branch canals are connected to the main canal at a right angle. It should be
constructed along with the contour line and never cross it to avoid water flowing to
the lower side. To achieve this goal, a detailed topographic survey is required, which
is described in detail below.
Both canals help the transportation of seedlings, materials, and equipment, as well
as laborers. In the case of forest/peat fire, the canals become fire belts to prevent
further spread of the fire. The canal water could also be used to extinguish fire.
Fortunately, WSL-MTI have never used to fight fire because such an incident has
never occurred in the plantation area.
3 Large-Scale Practice on Tropical Peatland Eco-Management
99
while comprehensively eliminating the weaknesses. Finally, WSL-MTI have
become familiar with proposing responsible peatland management in Indonesia,
taking into consideration the hydrology of the peat ecosystem, mainly the peat dome.
The GWL should be kept 0.4 m below the soil surface as stated in the government
regulations (ex. P.71/2014; P.57/2016) regarding the utilization of peatlands for
palm oil and pulpwood production (Indonesian Government Regulation 2016).
Although opinions that differed regarding the regulation of 0.4 m, WSL-MTI
considered 0.4 m to be the most preferred standard to avoid peat fires based on
observations of the relationship between the GWL and soil moisture content during
the dry season. Acacia trees also grow normally, as long as there are no major
fluctuations in the GWL. Conversely, drainage-based water management has only a
drainage function and no mechanism to control the water level, so the GWL cannot
be kept constant throughout the year, which sometimes leads to large fluctuations in
the GWL with the changing climate. Consequently, a constant standard for the GWL
regulated by the government has prevented good growth of acacia trees.
The water is sustained in peat by Intermolecular Force (van der Waals force). As
the intermolecular force of peat and water is not strong enough, water can easily be
released from peat when canals and ponds are made in peatland. In a degraded
peatland, a well-designed canal system is required to control GWL, distribute water
to the whole area, and plant trees for reforestation. Two types of canals are
recommended in the WSL-MTI plot design (Fig. 3.3). The main canal with a
width of 10–12 m and depth of 3 m, and branch canals with a width of 6–8 m and
depth of 3 m. The main canal should be constructed from the lower to the near upper
area such as the backbone in an animal body. The main canal should be completely
blocked by a peat dam every 0.5–0.6 m in elevation to prevent water from flowing
down to the lower side due to gravity. In the case of unpredictable heavy rain,
spillways, which are constructed at the same point of the peat dam, play an essential
role in discharging excess water from the upper to the lower side. Without spillways,
the planted area would be flooded by excessive water and severely damaged by an
extreme water level. It should be noticed that the spillway has a function of
controlling the flow volume and the speed of the excess water to prevent flooding
in the lower plantation area. The specifications of the spillway should be calculated
by an estimation of excess water volume and expected flow speed in relation to
maximum rainfall predicted.
The branch canals are connected to the main canal at a right angle. It should be
constructed along with the contour line and never cross it to avoid water flowing to
the lower side. To achieve this goal, a detailed topographic survey is required, which
is described in detail below.
Both canals help the transportation of seedlings, materials, and equipment, as well
as laborers. In the case of forest/peat fire, the canals become fire belts to prevent
further spread of the fire. The canal water could also be used to extinguish fire.
Fortunately, WSL-MTI have never used to fight fire because such an incident has
never occurred in the plantation area.
3 Large-Scale Practice on Tropical Peatland Eco-Management
99