Despite the lack of scientific publications presenting facts on spatial and temporal
distribution of artificial drainage canals in Indonesia, a number of studies showed
that the spatial extent of artificial drainage canals on peatland is enormous. For
instance, there were about 4400 km of artificial canals constructed for the development of one million hectare of rice farming project or known as the Ex-Mega Rice
Project (EMRP) in Central Kalimantan during the period of 1994–1996 (Dohong
and Lilia 2008). In addition, a study commissioned in a total area of 148,000 ha in
Sebangau National Park in Central Kalimantan found that there were 65 artificial
drainage canals constructed to support logging activities in past years (Jaenicke et al.
2010).
20.2.2 Prolonged Drought
During the extreme and prolonged drought event such as due to El Niño, peatland
experienced hydrological disturbance caused by, among others, the lack of precipitation and high evaporation resulting in physiological water deficit (Page and
Waldes 2008). This water deficit influences the water balance in peatland ecosystem
which is represented in groundwater drawdown particularly during the dry season.
Studies in Central Kalimantan proved that groundwater table during the dry
season can be several meters lower below the peat surface (Wosten et al. 2006;
Ballhorn et al. 2009). This disproportionate drawdown of groundwater level during
extreme dry season can affect the temperature of peat, rendering it to become
extremely hot, which in turn can kill the planted and natural seedlings and saplings
of woody and non-woody species on the ground (Page et al. 2009a, b). In the long
run, this situation will influence the hydrological dynamics in peatland ecosystem.
One of the significant impacts of GWL drawdown resulted from the water balance
deficit during drought is the deepening of the acrotelm layer (the oxidative upper
layer of peat), which in turn will exacerbate the peat subsidence and increase the
vulnerability of peatland against hydrophobic problem which can hamper hydrological restoration efforts.
20.3 Restoring Tropical Peatland Hydrology: Experience
in Indonesia
20.3.1 Peatland Hydrological Restoration in Indonesia
at a Glance
Restoration of drained peatland in Indonesia is considered still at the early development stage and many initiatives to restore peatland hydrology are still conducted
partially and in small scales in terms of nature and magnitude (Dohong et al.
570
A. Dohong and L. Tanika
distribution of artificial drainage canals in Indonesia, a number of studies showed
that the spatial extent of artificial drainage canals on peatland is enormous. For
instance, there were about 4400 km of artificial canals constructed for the development of one million hectare of rice farming project or known as the Ex-Mega Rice
Project (EMRP) in Central Kalimantan during the period of 1994–1996 (Dohong
and Lilia 2008). In addition, a study commissioned in a total area of 148,000 ha in
Sebangau National Park in Central Kalimantan found that there were 65 artificial
drainage canals constructed to support logging activities in past years (Jaenicke et al.
2010).
20.2.2 Prolonged Drought
During the extreme and prolonged drought event such as due to El Niño, peatland
experienced hydrological disturbance caused by, among others, the lack of precipitation and high evaporation resulting in physiological water deficit (Page and
Waldes 2008). This water deficit influences the water balance in peatland ecosystem
which is represented in groundwater drawdown particularly during the dry season.
Studies in Central Kalimantan proved that groundwater table during the dry
season can be several meters lower below the peat surface (Wosten et al. 2006;
Ballhorn et al. 2009). This disproportionate drawdown of groundwater level during
extreme dry season can affect the temperature of peat, rendering it to become
extremely hot, which in turn can kill the planted and natural seedlings and saplings
of woody and non-woody species on the ground (Page et al. 2009a, b). In the long
run, this situation will influence the hydrological dynamics in peatland ecosystem.
One of the significant impacts of GWL drawdown resulted from the water balance
deficit during drought is the deepening of the acrotelm layer (the oxidative upper
layer of peat), which in turn will exacerbate the peat subsidence and increase the
vulnerability of peatland against hydrophobic problem which can hamper hydrological restoration efforts.
20.3 Restoring Tropical Peatland Hydrology: Experience
in Indonesia
20.3.1 Peatland Hydrological Restoration in Indonesia
at a Glance
Restoration of drained peatland in Indonesia is considered still at the early development stage and many initiatives to restore peatland hydrology are still conducted
partially and in small scales in terms of nature and magnitude (Dohong et al.
570
A. Dohong and L. Tanika