20.1 Introduction
Peat is formed through a long-term accumulation (may take several hundred up to
thousands of years) of organic matters, particularly decayed plants, in waterlogged,
acidic, and low-nutrient environment (Rieley and Page 2008; Yule 2010). Further,
accumulation of peat layer only occurs when the rate of organic matters production
exceeds the rate of decomposition (Hooijer 2013). An area covered by peat is
commonly called as peatland (Rieley and Page 2008). Ninety percent of natural
peat consists of water, ten percent of which constitutes decayed plant remnants
(Jaenicke et al. 2011; Dohong et al. 2017a, b).
Tropical peatland constitutes only about 12% of the global peatland area and is
mainly located in East Asia, Southeast Asia, Southern Africa, the Caribbean, as well
as Central and South America (Rieley and Page 2008; Jaenicke et al. 2010; Page
et al. 2009a, b). Over 56% (equivalent to 24.78 Mha) of the global peatland area is
situated in Southeast Asia (Page et al. 2009a, b).
Currently, according to official government data, Indonesia has a total of 14.9
million hectares (Mha) of peatland area, with total peatland hydrological unit (PHU)
of 865 units covering total area of 24.22 Mha (Ritung et al. 2011). This peatland is
spatially distributed in three main islands, namely Sumatra (6.44 Mha, 43.22%),
Kalimantan (4.78 Mha, 32.08%), and Papua (3.69 Mha, 24.77%). Based on the peat
depth class, Indonesia’s peatland is divided into shallow peat (<3 m), comprising
around 9.60 Mha (64.40%), and deep peat (>3 m), comprising about 5.30 Mha
(35.60%) (Wahyunto and Agus 2016). In addition, peatland in Indonesia stores
carbon in the peat range between 13.6 and 57.4 GtC (Harrison et al. 2019). This
immense carbon storage plays an important role, namely controlling climate change
at the regional and global level.
Despite the tremendous socio-ecological values and services as mentioned above,
peatland in Indonesia has experienced high rate of degradation due to land use
conversion and transformation such as through logging, large-scale industrial plantation, drainage, and recurrent fires taking place due to the conversion (Hooijer et al.
2006, 2012; Koh et al. 2011; Miettinen et al. 2012; Margono et al. 2014; Dohong
et al. 2017a, b).
Moreover, the construction of artificial drainage canals to support activities,
namely logging, agriculture, and industrial plantation has scaled up the degree of
peatland degradation in Indonesia. The existence of artificial canals has impacted the
hydrological balance in peatland due to the increase of surface water runoff and
decrease of the water table in the peat. This disrupts the integrity of the peatland’s
hydrological properties, which in turn promotes drying out and aerobic decomposition, leading to substantial losses of peat profile and peat carbon (Hooijer et al. 2006;
Wosten et al. 2006; Page et al. 2009a, b).
One strategy to address the disturbed hydrology of peatland is hydrological
restoration through the implementation of hydrological intervention measures such
as canal blocking, canal backfilling, and other suitable water control measures to
maintain the desired groundwater and surface water level in the drained peatland
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A. Dohong and L. Tanika
Peat is formed through a long-term accumulation (may take several hundred up to
thousands of years) of organic matters, particularly decayed plants, in waterlogged,
acidic, and low-nutrient environment (Rieley and Page 2008; Yule 2010). Further,
accumulation of peat layer only occurs when the rate of organic matters production
exceeds the rate of decomposition (Hooijer 2013). An area covered by peat is
commonly called as peatland (Rieley and Page 2008). Ninety percent of natural
peat consists of water, ten percent of which constitutes decayed plant remnants
(Jaenicke et al. 2011; Dohong et al. 2017a, b).
Tropical peatland constitutes only about 12% of the global peatland area and is
mainly located in East Asia, Southeast Asia, Southern Africa, the Caribbean, as well
as Central and South America (Rieley and Page 2008; Jaenicke et al. 2010; Page
et al. 2009a, b). Over 56% (equivalent to 24.78 Mha) of the global peatland area is
situated in Southeast Asia (Page et al. 2009a, b).
Currently, according to official government data, Indonesia has a total of 14.9
million hectares (Mha) of peatland area, with total peatland hydrological unit (PHU)
of 865 units covering total area of 24.22 Mha (Ritung et al. 2011). This peatland is
spatially distributed in three main islands, namely Sumatra (6.44 Mha, 43.22%),
Kalimantan (4.78 Mha, 32.08%), and Papua (3.69 Mha, 24.77%). Based on the peat
depth class, Indonesia’s peatland is divided into shallow peat (<3 m), comprising
around 9.60 Mha (64.40%), and deep peat (>3 m), comprising about 5.30 Mha
(35.60%) (Wahyunto and Agus 2016). In addition, peatland in Indonesia stores
carbon in the peat range between 13.6 and 57.4 GtC (Harrison et al. 2019). This
immense carbon storage plays an important role, namely controlling climate change
at the regional and global level.
Despite the tremendous socio-ecological values and services as mentioned above,
peatland in Indonesia has experienced high rate of degradation due to land use
conversion and transformation such as through logging, large-scale industrial plantation, drainage, and recurrent fires taking place due to the conversion (Hooijer et al.
2006, 2012; Koh et al. 2011; Miettinen et al. 2012; Margono et al. 2014; Dohong
et al. 2017a, b).
Moreover, the construction of artificial drainage canals to support activities,
namely logging, agriculture, and industrial plantation has scaled up the degree of
peatland degradation in Indonesia. The existence of artificial canals has impacted the
hydrological balance in peatland due to the increase of surface water runoff and
decrease of the water table in the peat. This disrupts the integrity of the peatland’s
hydrological properties, which in turn promotes drying out and aerobic decomposition, leading to substantial losses of peat profile and peat carbon (Hooijer et al. 2006;
Wosten et al. 2006; Page et al. 2009a, b).
One strategy to address the disturbed hydrology of peatland is hydrological
restoration through the implementation of hydrological intervention measures such
as canal blocking, canal backfilling, and other suitable water control measures to
maintain the desired groundwater and surface water level in the drained peatland
568
A. Dohong and L. Tanika