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Planning hydrological restoration of peatlands in Indonesia to mitigate carbon dioxide emissions

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Extensive degradation of Indonesian peatlands by deforestation, drainage and recurrent fires causes release of huge amounts of peat soil carbon to the atmosphere. Construction of drainage canals is associated with conversion to other land uses, especially plantations of oil palm and pulpwood trees, and with widespread illegal logging to facilitate timber transport. A lowering of the groundwater level leads to an increase in oxidation and subsidence of peat. Therefore, the groundwater level is the main control on carbon dioxide emissions from peatlands. Restoring the peatland hydrology is the only way to prevent peat oxidation and mitigate CO2 emissions. In this study we present a strategy for improved planning of rewetting measures by dam constructions. The study area is a vast peatland with limited accessibility in Central Kalimantan, Indonesia. Field inventory and remote sensing data are used to generate a detailed 3D model of the peat dome and a hydrological model predicts the rise in groundwater levels once dams have been constructed. Successful rewetting of a 590 km² large area of drained peat swamp forest could result in mitigated emissions of 1.4–1.6 Mt CO2 yearly. This equates to 6% of the carbon dioxide emissions by civil aviation in the European Union in 2006 and can be achieved with relatively small efforts and at low costs. The proposed methodology allows a detailed planning of hydrological restoration of peatlands with interesting impacts on carbon trading for the voluntary carbon market.
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Planning hydrological restoration of peatlands
in Indonesia to mitigate carbon dioxide emissions
Julia Jaenicke &Henk Wösten &Arif Budiman &
Florian Siegert
Received: 18 September 2009 /Accepted: 5 January 2010 /
Published online: 3 February 2010
#The Author(s) 2010. This article is published with open access at
Abstract Extensive degradation of Indonesian peatlands by deforestation, drainage and
recurrent fires causes release of huge amounts of peat soil carbon to the atmosphere.
Construction of drainage canals is associated with conversion to other land uses, especially
plantations of oil palm and pulpwood trees, and with widespread illegal logging to facilitate
timber transport. A lowering of the groundwater level leads to an increase in oxidation and
subsidence of peat. Therefore, the groundwater level is the main control on carbon dioxide
emissions from peatlands. Restoring the peatland hydrology is the only way to prevent peat
oxidation and mitigate CO
emissions. In this study we present a strategy for improved
planning of rewetting measures by dam constructions. The study area is a vast peatland
with limited accessibility in Central Kalimantan, Indonesia. Field inventory and remote
sensing data are used to generate a detailed 3D model of the peat dome and a hydrological
model predicts the rise in groundwater levels once dams have been constructed. Successful
rewetting of a 590 km² large area of drained peat swamp forest could result in mitigated
emissions of 1.41.6 Mt CO
yearly. This equates to 6% of the carbon dioxide emissions by
civil aviation in the European Union in 2006 and can be achieved with relatively small
efforts and at low costs. The proposed methodology allows a detailed planning of
hydrological restoration of peatlands with interesting impacts on carbon trading for the
voluntary carbon market.
Keywords Dam construction .Drainage canal .Groundwater level rise .
Hydrological modelling .Illegal logging
Mitig Adapt Strateg Glob Change (2010) 15:223239
DOI 10.1007/s11027-010-9214-5
J. Jaenicke (*):F. Siegert
GeoBio Center, Ludwig-Maximilians-University Munich & Remote Sensing Solutions GmbH,
Wörthstrasse 48, 81667 München, Germany
H. Wösten
Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen,
The Netherlands
A. Budiman
WWF-Indonesia, Kantor Taman A9, Unit A-1, Kawasan Mega Kuningan, Jakarta 12950, Indonesia
1 Introduction
Of the tropical peatlands worldwide 70% are located in Southeast Asia, 22 million ha of
these in coastal and sub-coastal regions on the islands of Sumatra, Borneo and West Papua
in Indonesia (Page and Banks 2007). Tropical peat is an accumulation of partially decayed
organic matter which has been formed over thousands of years in waterlogged environ-
ments that lack oxygen. In Indonesia peat deposits with up to 20 m in thickness store huge
amounts of carbon (Whitten et al. 1987; Sorensen 1993; Jaenicke et al. 2008). Under
undisturbed conditions, tropical peatlands are covered with peat swamp forests which
comprise ecosystems with many endemic species and high biodiversity. Since the 1980s the
Indonesian peatlands have been extensively logged, drained and converted to plantation
estates as a result of economic development (Curran et al. 2004; Rieley and Page 2005;
Hansen et al. 2009). In Southeast Asia 12 million ha of peatlands are currently deforested
and drained, including over 1.5 million ha of tropical peat swamp forests in the Indonesian
province of Central Kalimantan (Hooijer et al. 2006). Canals and ditches are not only built
to control and lower the groundwater level for plantation operations and small-scale
agriculture but also to facilitate access to peat swamp forests and to extract timber logs. The
extent of these diverse canals and thus the impact on drainage depth varies. For example,
the drainage depth of oil palm plantations in Sarawak, Malaysia, is 60 cm (Melling et al.
2005) whereas it is about 30 cm in farm fields in Central Kalimantan, Indonesia
(Jauhiainen et al. 2004).
Once peat is drained, it oxidises due to microbial activity and releases stored carbon to
the atmosphere as carbon dioxide. This ongoing rapid peat decomposition leads to the
irreversible process of peatland subsidence. In developed peat, drainage depth is related to
peat organic matter oxidation rates and peat subsidence (Wösten et al. 1997; Furukawa et
al. 2005). On average 60% of peat subsidence is caused by oxidation and 40% by
irreversible drying or shrinkage of the peat (Wösten et al. 1997). Lowering the groundwater
level which naturally is close to the peat surface throughout the year while fluctuating with
the intensity and frequency of rainfall, results in an increase in CO
emissions. In a recent
review it is estimated that an increase of drainage depth by 10 cm results in the emission of
about 9 t CO
(Couwenberg et al. 2009).
Another severe consequence of drainage is the occurrence of peat fires. Under natural
circumstances peat consists of 90% water and 10% plant matter and hardly ever burns.
However, if the groundwater level falls below a critical threshold of 40 cm, the dry peat
surface becomes susceptible to fire (Takahashi et al. 2003;Usupetal.2004; Wösten et al.
2008). Fires are most severe during El Niño events, as in 1997/98 when about 2.46.8 million
ha of peatlands burnt in Indonesia releasing huge amounts of the greenhouse gas CO
et al. 2002; Van der Werf et al. 2008). With a groundwater level at about 100 cm the burn
depth was estimated to be 51 cm on average releasing up to 9.4 Gt of carbon dioxide in
Indonesia (Page et al. 2002). The failed Mega Rice Project, a resettlement project initiated in
1995 in Central Kalimantan, contributed largely to this ecological devastation. Drainage
canals, up to 30 m wide and 10 m deep, with a combined length of 4,500 km disrupted the
peatland ecosystem over an area of more than 1 million ha. There exists a positive feedback
of recurrent fires which leads to progressive forest degradation and continuous release of CO
with regional and global consequences for the environment and climate (Siegert et al. 2001;
Cochrane 2003; Langner et al. 2007).
Complete rewetting is the only way to prevent fires and peat oxidation by microbial
decomposition. Due to its high permeability peat acts as a sponge, i.e. it shrinks when dried
and swells when rewetted, unless water contents fall below a threshold value at which
224 Mitig Adapt Strateg Glob Change (2010) 15:223239
irreversible drying occurs (Wösten et al. 2008). Therefore, one of the most important peatland
restoration measures is blocking of drainage canals by dams and thus raising the groundwater
level of the surrounding peatland. Damming activities performed in the former Mega Rice
Project area, in Sebangau National Park and in Merang peatland of South Sumatra have
shown that the water retention upstream of dams could be increased thereby decreasing peat
desiccation during the dry season (Suryadiputra et al. 2005;CKPP2008;Jauhiainenetal.
2008). Few rehabilitation attempts have been undertaken in the past (Page et al. 2008),
however within the context of ongoing discussions concerning climate change tropical
peatlands have now been recognised as major sources of greenhouse gas emissions (Rieley
and Page 2005; Hooijer et al. 2006;Uryuetal.2008). The carbon content of the peat soils in
Indonesia is about 18 times higher than that of pristine peat swamp forest (Jaenicke et al.
2008). Therefore, peatland rehabilitation projects are of high interest for carbon trading on the
voluntary carbon market. While peat oxidation causes continuous release of carbon dioxide,
peat fires are the source of huge amounts of CO
emissions in short time. These emissions
can be mitigated if peatland rewetting measures are implemented.
The objective of this study was the development of an efficient and cost-effective
methodology to plan hydrological restoration of disturbed tropical peatlands. The study was
conducted in the Sebangau catchment in Central Kalimantan under supervision of the
World Wildlife Fund (WWF) aiming at mitigation of carbon dioxide emissions. The surface
of tropical peat shows little slope; with gradients of only 0.21 m per kilometre in the centre
they appear virtually flat (Page et al. 1999; Rieley and Page 2005). In addition, the
Sebangau peat dome is covered with dense vegetation which makes an in situ assessment of
the entire hydrology impossible. The proposed restoration programme comprises several
steps: 1) planning: selection of locations best suited for effective restoration measures and
dam construction, 2) hydrological modelling: predicting the effect of dams, 3) implemen-
tation: dam construction, 4) monitoring: monitoring the performance of dams in time. The
methodology presented here for steps 1) and 2) builds on a combined approach of field
inventory, remote sensing, geospatial analysis and 3D peat dome topography assessment as
well as sophisticated hydrological modelling. Steps 3) and 4) are briefly discussed in
Section 4and will remain as a future research topic.
2 Study area, materials and methods
2.1 Study area
The hydrological restoration project will be carried out in a 1,480 km² area of the Sebangau
catchment which is located in the Indonesian province of Central Kalimantan on the island
of Borneo (Fig. 1). The catchment is part of a 7,347 km² large peat dome which contains
the largest remaining continuous area of dense peat swamp forest in Borneo and stores
about 2.3 Gt of peat soil carbon (Jaenicke et al. 2008). The extent of the study area is
defined by natural, hydrological borders, i.e. the Sebangau River to the east, tributary
streams to the southwest and north and the highest elevation of the peat dome to the
northwest. As most Indonesian peatlands the Sebangau peat dome is ombrogenous, i.e.
rainfall is the only source of water and nutrients. Organic matter accumulation started
around 26,000 years ago (Page et al. 2004). The climate of Central Kalimantan is
determined by a dry season which usually begins in May and lasts until October and a wet
season from November until April. Annual rainfall varies between 2,000 and 4,000 mm and
is influenced by periodic El Niño events which cause a prolonged dry season. During the
Mitig Adapt Strateg Glob Change (2010) 15:223239 225
dry season the groundwater level in the peat drops as precipitation decreases. The Sebangau
ecosystem is renowned for its high conservation value and important natural resource
functions. Consequently, the Sebangau catchment was designated as National Park in 2004,
also to protect the largest population in the world of the endangered Bornean orang-utan.
Nevertheless, the Sebangau peat dome is suffering from serious drainage in recent years
due to the construction of hundreds of canals by illegal loggers. Until 1997 timber
concessions constructed thousands of kilometres of simple railway tracks to transport felled
timber to the Sebangau River (Boehm and Siegert 2004). The concession companies
removed their infrastructure equipment but illegal loggers excavated canals along the
former railway tracks to enable timber transport (Fig. 2). Difficult access restricts the
knowledge of the total number of canals in Sebangau peat dome to estimations by local
fisherman and environmental organisations. In this study, field surveys were conducted to
map all canals within two specific areas located in the eastern part of the peatland. Burn
scars occurring on Landsat satellite imagery since 1997 as well as fire hotspots yearly
detected by the MODIS satellite sensors (FIRMS 2009) demonstrate the negative impacts
of canal drainage on the Sebangau peatland.
The eastern part of the Sebangau catchment was selected for hydrological restoration due
to its vicinity to the city of Palangka Raya and its relative easy access via the Sebangau
Fig. 1 Landsat ETM+ satellite image from August 2007 showing the study area located in Central
Kalimantan on the island of Borneo, Indonesia. Dark green: peat swamp forest, red: fire scars in the year
226 Mitig Adapt Strateg Glob Change (2010) 15:223239
River and tributary streams. Two water sub-catchments, named after their main outlet rivers
Bakung and Bangah, were identified for the project (Fig. 1). Outlet rivers give loggers
access to the forest and thus most drainage canals start there. On the basis of a Digital
Terrain Model (DTM) the two catchments were delineated comprising a total area of
590 km². It is assumed that if all canals actually draining the peat within a specific
catchment are blocked, it will be possible to permanently raise groundwater levels to the
original situation in which groundwater levels are normally at or close to land surface.
2.2 Remote sensing
Difficult access of tropical peat swamp forests and limited project funds, require the use of
remote sensing data and modelling techniques in combination with field surveys of canal
attributes. Optical satellite imagery from Landsat ETM+, SPOT HRVIR and ALOS AVNIR
sensors, radar satellite data from the Shuttle Radar Topography Mission (SRTM) and high
resolution airborne laser scanning data (LIDAR) were used to: 1) generate a Digital Terrain
Model (DTM) of the peat surface and determine peat thickness, and 2) localise drainage
canals for hydrological modelling of groundwater levels. Hydrological modelling allows
identification of areas with good restoration potential and helps to optimise the number and
location of dams required for rewetting a specific area. Canal location, length, width, depth
and slope as well as peat bulk density, hydraulic conductivity and the stratification by peat
thickness are required parameters for the modelling.
LIDAR (LIght Detection And Ranging) measurements were acquired in August 2007 for
the northern part of the study area along a 34 km long and 0.4 km wide flight stripe running
from west to east. LIDAR systems are active, airborne remote sensing systems which
radiate pulses of laser light to the terrain and measure the time delay between transmission
of the pulse and measurement of the reflected signal by the sensor. The three dimensional
clouds of points were differentiated into ground points and non-ground points reflected
from vegetation. To extract ground points from vegetation points the terrain-adaptive bare
Fig. 2 Typical drainage canal in the Sebangau catchment used to transport timber
Mitig Adapt Strateg Glob Change (2010) 15:223239 227
earth filtering algorithm from Cloud Peak software was applied (Ballhorn et al. 2009).
LIDAR measurements allow assessing the terrain height beneath forests with unrivalled
accuracy. The ground surface generated by airborne Laser data has a spatial resolution of
1 m. LIDAR data were used to assess the peat dome topography across the Sebangau
catchment and to validate the DTM generated for the study area.
The elevation of the DTM was calculated from SRTM imagery acquired in February
2000. Kriging interpolation in ArcGIS was used to generate a dome shaped peat surface
model as indicated by the LIDAR and SRTM data. For this surface grid points at 500
1,000 m intervals extracted from the SRTM data, were interpolated. SRTM data represent in
deforested peat areas a Digital Terrain Model (DTM), i.e. bare-earth model. However, in
forested areas they display a so called Digital Surface Model (DSM) because the SRTM C-
band radar sensor does not penetrate the dense peat swamp forest cover. The tree canopy
height was estimated by means of deforested patches, like burn scars, rivers and canals.
Different peat swamp forest types were identified by analysing their texture variations in the
radar imagery in combination with spectral information from a Landsat ETM+ image also
acquired in February 2000. The terrain model, together with peat drilling data, formed the
basis for modelling peat thickness. Peat thickness drillings using manually operated peat
corers are laborious and expensive. The limited terrain accessibility restricts these drillings
usually to sites adjacent to drainage canals and along logging railway tracks. A total of 129
drilling measurements were available for the study area but not evenly distributed to
directly apply spatial interpolation. Therefore, correlation was used to provide missing peat
thickness information (Jaenicke et al. 2008). The correlation function makes use of a
biconvex shape model typically for ombrogenous, tropical peatlands (Rieley and Page
2005; Jaenicke et al. 2008). A strong correlation coefficient of r=0.87 was obtained
between peat surface and peat thickness.
2.3 Hydrological modelling
For hydrological modelling, the physically-based SIMGRO (SIMulation of GROundwater
flow and surface water levels) model was used to simulate water flow in the saturated zone,
unsaturated zone, river channels and over the peat surface (Querner et al. 2008; Querner
and Povilaitis 2009). Using the DTM and the watercourses map, delineations of the project
area were determined with the hydrology extension in the GIS package ArcView. Saturated
groundwater flow was modelled using the finite element method for which the model area
was subdivided into triangular segments. The top of the mineral layer was set as aquifer
bottom. Hydraulic conductivity of the peat is an essential element of hydrological
modelling. In turn, the hydraulic conductivity and also the moisture retention relationship
of the peat is strongly influenced by the degree of humification of the peat. Based on
hydraulic conductivity measurements using the pumping test method as reported by Ong
and Yogeswaran (1992) and by Takahashi and Yonetani (1997) the peat profile in this study
is schematised in a two layer system consisting of a fibric to hemic peat top layer (01m)
with an average hydraulic transmissivity (cumulative thickness multiplied by conductivity)
of 30 m
and a deeper, sapric peat layer with an average hydraulic transmissivity of
2.2 m
. While using these average values it should be realised that the relatively few
measurements available for tropical peatlands show a considerable range. In addition, a peat
water storage coefficient is required as a model input parameter. This coefficient was not
measured directly but obtained in the model calibration process and set to 0.5 (Wösten et al.
2006). Groundwater levels calculated using both the original and calibrated model for the
test site directly south of Palangka Raya (Fig. 1) are shown in Fig. 3a. The correlation
228 Mitig Adapt Strateg Glob Change (2010) 15:223239
coefficient (R
), the root mean square error (RMSE) and the mean square error (MSE) for
the calibrated model are 0.74, 5.22 and 7.79 respectively. After calibration the model was
validated and the results are shown in Fig. 3b. The calibrated and validated model
represents groundwater levels measured in a dip well at the test site with acceptable
accuracy (within 0.10 m).
3 Results
3.1 Peat dome 3D topography
The 3D topography of the peat layer is an essential input for hydrological modelling of
groundwater levels. The DTM of the peat dome surface was used for slope calculations to
identify water sub-catchments and to determine the number and location of dams for
hydrological restoration. LIDAR data analysis showed that the surface of the Sebangau peat
dome towards the centre is elevated by a maximum of 13 m above its margins with an
average gradient of 0.7 m per kilometre which appears flat when in the field (Fig. 4). The
SRTM derived peat dome surface correlates very well with the LIDAR measurements; the
average discrepancy is only 0.35 m (Fig. 4). The LIDAR as well as SRTM DSM reveal
Fig. 3 Measured and calculated groundwater levels relative to land surface at the test site (Lat = 2.323S, Lon =
113.903 E) versus time. aModel calibration, bModel validation
Mitig Adapt Strateg Glob Change (2010) 15:223239 229
different peat swamp forest types (low, medium, tall pole), which in accordance with field
investigations have different maximum canopy heights depending on local substrate
conditions (Page et al. 1999). Biomass data, i.e. breast height diameter, tree height and tree
species, were collected in October 2007 and 2008 along the transect shown in Fig. 4and
these data confirm the results. Even across large distances with little relief it is possible to
derive the DTM from the SRTM DSM using spatial interpolation between deforested
patches. The result was a detailed DTM of the Sebangau peat dome and its sub-catchments
with 30 m spatial resolution. Figure 5shows the fine topography along cross sections in the
middle of Bakung and Bangah catchments. The slope of the southern part of Bakung
catchment appears relatively steep but the gradient is only 1 m per kilometre at maximum.
Besides detailed peat dome topography, hydrological modelling requires peat thickness and
bedrock data. The result of the thickness modelling reveals an average peat thickness of
5.4±0.95 m within the study area and a maximum depth of approximately 10.7 m in the
centre of the Sebangau peat dome. The margin of error results from comparison of the peat
thickness model with in situ measurements. The large deviations result probably from
bedrock unconformity, which is not taken into account in the model. About half of the in
Fig. 4 The LIDAR DTM and the peat surface derived from SRTM data (Model) agree very well. The SRTM
DSM data reveal relative canopy heights of various peat swamp forest types
Fig. 5 DTM cross sections in the middle of the Bakung and Bangah catchment (from north to south)
230 Mitig Adapt Strateg Glob Change (2010) 15:223239
situ thickness values are larger than the model result, while the other half are smaller. This
suggests that discontinuities in the mineral ground topography are balanced by spatial
Kriging interpolation and thus the modelled volume results are close to reality (Jaenicke et
al. 2008).
3.2 Canal delineation
During field surveys in the Bakung and Bangah catchments the origin of 65 drainage canals
was recorded. Eventually all these canals need to be blocked to rewet the surrounding
peatland. The field team also recorded direction, length, width and depth of all canals as
well as water depth, water flow, mud sedimentation or weed growth. With an average depth
of 0.7 m and an average width of 2.4 m the canals are relatively small in terms of their
cross-sectional dimensions, but they are closely spaced with an average distance of about
200 m in the Bakung and of about 800 m in Bangah catchment and they extent for distances
up to 13 km. All information was stored in a geodatabase and a ranking was assigned
indicating the priority of a canal to be closed. Long, wide and deep canals with a high water
level and flow were assigned a high priority, whereas canals filled with mud and weeds
were categorised as low priority. Twenty-two canals showed a high or medium need for
closure. Canal lengths were estimated by consulting local people since access to the canals
is very laborious and because GPS recordings are inaccurate due to dense forest cover
hampering the GPS receiver. Narrow canals were invisible even from high resolution
satellite images (SPOT and ALOS AVNIR, both at 10 m spatial resolution) because the tree
canopy covers the streams (Fig. 6). However, knowing the outlet of the canal, the direction
and approximate length it was possible to delineate most canals.
Fig. 6 SPOT satellite image
from May 2004 showing the
course of canals and railway
tracks in the Bangah catchment as
bright green lines as well as sites
of illegal logging (pink and bright
green dots). The origin of
drainage canals recorded during
field work is superimposed as
yellow dots
Mitig Adapt Strateg Glob Change (2010) 15:223239 231
3.3 Identification of locations for dam construction
Dams act as flow barriers but they cannot store water for long periods as water will
eventually seep through the surrounding peat. As dams restrict water flow rather than stop
all water movement, they do not have to be watertight and thus construction can be
relatively simple. To determine the optimal number and location of dams required for
efficient drainage reduction, the surface slope was determined along each canal selected to
be closed. Hydrological model simulations revealed that a cascade of closely spaced dams
is most effective for water control (Wösten and Ritzema 2001). The steeper the slope, the
more dams are needed to reduce drainage. Figure 7shows the slope of a medium priority
canal in the Bangah catchment (length 10 km, width 3 m, depth 1 m). The absolute
elevation difference of the canal from its origin at the top of the peat dome to its outlet into
Bangah river is 3.1 m. Because the slope of the canal is not constant over its total length it
was subdivided into two sections: an upper, relatively flat section (Fig. 7, Slope1) and a
lower, steep section (Fig. 7, Slope2). The distance between dams required to reduce
drainage is determined by the hydraulic head difference, i.e. difference between upstream
and downstream canal water level across a dam. Field experiments showed that for small
canals the water level over each dam should be limited to about 25 cm to reduce seepage
and to prevent erosion. Thus, the canal in Fig. 7requires a series of 13 dams to overcome
the 3.1 m elevation difference
. In the upper section of the canal a spacing of 975 m
between dams is sufficient to keep water level differences low, while in the steeper section
the spacing needs to be reduced to 320 m. The Bakung catchment requires the construction
of 141 dams to efficiently reduce drainage. For the Bangah catchment 84 dams are
needed in addition to 30 dams previously constructed. Figure 8shows the location of
dams planned and already built, as well as the priority status of the canals superimposed on
the DTM. The Bakung catchment is smaller than Bangah catchment but requires more
dams because of the steeper topography and higher density of canals to be closed. Figure 9
shows an example of a relatively simple dam in the Bangah catchment mainly made of
locally available material.
3.4 Prediction of groundwater level rise
The effect of dams on groundwater levels is predicted by hydrological modelling comparing the
situation before and after dam construction. Figure 3shows that in wet years calculated
groundwater levels are at or close to land surface whereas in dry years they drop to about 1 m
below land surface. On average the groundwater level at the undisturbed test site is 16 cm.
This value provides an indication of the intended long-term average groundwater level after
successful blocking of drainage canals in the Bakung catchment. The calibrated and validated
hydrological model was applied to the whole of the Bakung and Bangah catchment for the 25
November 1997, an extremely dry period. Figure 10a shows that dams can raise groundwater
levels up to 5070 cm under these very dry weather and peat conditions. For larger areas the
H slope1ðÞ=0:25 þH slope2ðÞ=0:25 þ...þH slopen
ðÞ=0:25 ¼N damsðÞ
D slopen
=N dams
¼S dams
H maximum elevation difference of the canal within each slope section
N optimum number of dams (rounded up to be on the save side)
D distance of each slope section
S spacing between dams
232 Mitig Adapt Strateg Glob Change (2010) 15:223239
rise is approximately 1030 cm. Rise in groundwater levels is presented in classes rather than
as absolute values to reflect the uncertainty in the calculated results. The areas affected by
rewetting are strongly influenced by the slope of the peatland area surrounding the canal as this
determines the catchment area draining to the canal. Figure 10b shows surface water levels in a
12 km long canal. Compared to the situation without dams, the result is a rise of the canal water
level of up to 35 cm in the upstream part of the canal. The resulting rewetting of the peatland
area surrounding this canal is up to 50 cm. Hydrological modelling of the rise of groundwater
levels on a daily base for the years 2006, 2007 and 2008 shows that on average this rise is
20 cm during the dry season. As a consequence, construction of dams considerably increases
Fig. 7 Slope of the peat surface
next to a canal in Bangah catch-
ment as measured in the modelled
DTM (0 marks the most upstream
part of the canal). 13 dams are
required to reduce large scale
Fig. 8 Location of dams to be
constructed for an efficient re-
duction of drainage in the
Bakung and Bangah catchments.
Only canals ranked as medium
and high priority should be
closed. Data are superimposed on
the peat surface DTM
Mitig Adapt Strateg Glob Change (2010) 15:223239 233
the water retention capacity of the blocked areas thereby creating favourable wet conditions for
vegetation re-growth and eventually peatland restoration.
3.5 Mitigation of carbon dioxide emissions
Rewetting of drained tropical peatlands will potentially lead to large mitigations of carbon
dioxide emissions (Couwenberg et al. 2009). Quantifying the rise in groundwater levels of
hydrological restoration projects in peatlands together with an estimation of the mitigation
in CO
emissions caused by this rise, is important information to make greenhouse gas
emission mitigations tradable under the voluntary carbon market or REDD (Reducing
Emissions from Deforestation and Degradation) mechanism. Continuous, long-term
groundwater level measurements in tropical peat swamp forests are rare. The only available
12 year average groundwater level recorded at the relatively intact test site is 16 cm,
whereas this level in an adjacent, drainage affected, selectively logged forest is 47 cm for
the years 2004 and 2005 with normal precipitation (Jauhiainen et al. 2008). Preliminary
groundwater level measurements in the drainage affected Bangah catchment indicate an
average level of 49 cm. Consequently, an average annual groundwater level of 50 cm
was assumed to be a baseline level for the project area before hydrological restoration
started. After construction of all dams, hydrological modelling indicates a rise of annual
average groundwater levels of 20 cm. With a reported emission mitigation of approximately
0.80.9 t CO
per centimetre groundwater level rise (Couwenberg et al. 2009;
Hooijer et al. 2006), rewetting of the 590 km
area of the combined Bakung and Bangah
catchments results in an estimated mitigated emission of 1.41.6 Million tons CO
annually. This estimated emission mitigation will not be achieved in the first year after all
dams have been constructed because only with time sedimentation of organic and mineral
material upstream of the dams makes them fully effective. Higher emissions are expected
during El Niño years, such as in 1997, 2002, 2006 and 2009 due to very low groundwater
Fig. 9 Simple dam in the Bangah catchment made of locally available material (3 m long, 1 m wide and
2.5 m deep)
234 Mitig Adapt Strateg Glob Change (2010) 15:223239
levels in addition to drainage. In the project area, long-term measurements of groundwater
levels (before and after dam construction) as well as subsidence and gas flux emissions are
needed to confirm these preliminary results. In this study, conservative estimates were used of
both the reduced CO
emission rate per centimetre groundwater level rise (Couwenberg et al.
2009; Hooijer et al. 2006) as well as of the magnitude of the groundwater level rise itself.
Results are reported as a class to reflect the uncertainty in the calculations. Other greenhouse
gases such as methane (CH
) and nitrous oxide (N
O) are not taken into account because they
are relatively unimportant in tropical peatlands (Furukawa et al. 2005; Strack 2008).
4 Discussion
Canals constructed for drainage and illegal logging have destroyed the hydrological integrity of
many tropical peatland ecosystems (e.g. Giesen 2004;Wöstenetal.2006; Hoekman 2007;
CKPP 2008). The only way to prevent soil subsidence, peat decomposition, peat fires and
Fig. 10 Hydrological modelling
applied to the Bangah catchment
for very dry conditions on 25
November 1997. aGroundwater
level rise in the whole area after
construction of 114 small dams b
Rise of the surface water level
(swl) in a single canal after dam
Mitig Adapt Strateg Glob Change (2010) 15:223239 235
associated carbon dioxide emissions is the restoration of the hydrological integrity by raising
groundwater levels and thus rewetting the peat to its original situation. Many studies have
shown that groundwater levels control greenhouse gas emissions from tropical peatlands (e.g.
Furukawa et al. 2005; Hooijer et al. 2006; Hirano et al. 2008; Jauhiainen et al. 2008;
Couwenberg et al. 2009). However, very few practical hydrological restoration measures of
degraded tropical peatlands have been reported (Jauhiainen et al. 2008;Pageetal.2008). The
aim of this study was to develop a detailed plan to rewet a 590 km² large area of highly
inaccessible peat swamp forest drained by a dense network of small canals that are used by
illegal loggers. The case as such is typical for many tropical peatlands in Indonesia and the
proposed methodology is transferable to other drained tropical peatlands thereby increasing the
knowledge base for future hydrological restoration activities. A detailed 3D peat dome model
generated using remote sensing data, together with identified dam construction sites, provided
input for hydrological modelling to quantify the effects of dams on raising groundwater levels.
To verify the calculated groundwater levels a monitoring programme is under construction
aiming at measurement of these levels in wells installed at a dam along two transects left and
right, and perpendicular to the canal at 5, 25, 50, 150 and 300 m distances from the canal. Also
water discharges will be measured in both blocked and unblocked canals. In this study wider
canals were clearly visible in high resolution satellite imagery, while hardly visible, smaller
canals were determined as follows: 1) canals do not run parallel to the river or cross each other
because they are constructed to facilitate extraction of timber logs from the forest, 2) while in
reality the course of the canals might be not completely straight, small meanders do not have
any impact on the number of dams required for rewetting. Dams need to be adapted to the
characteristic high hydraulic conductivity (Wösten and Ritzema 2001) and low load bearing
capacity (Salmah 1992) of tropical peat. Reduced water flow in the canals allows sedimentation
of organic and mineral material upstream of the dam which in turn facilitates the re-growing of
vegetation. Eventually, original peat forming vegetation will fill in the canal thereby restoring
the resistance to water flow in the peat swamp forest to its original value of approximately
30 m/day. To keep subsidence of the area surrounding the dam low, dam construction should
not be too heavy. Materials like gelam timber poles and peat are suitable for dam construction
and they are locally available. Blocking of a canal can be regarded successful if the blocked
canal sections continue to hold water during the dry season. Since some drainage canals are
used for navigation and transportation by local people, ownership of each canal should be
considered and consensus should be reached before dam construction starts. Failure to do so
can result in damage to the dam structures as has happened frequently in the past. After
construction, monitoring and maintenance of the dams is very important, especially in the first
years (CKPP 2008). Previous work in the Bangah catchment demonstrated that a field team can
build 30 dams in 7 days, i.e. 53 days are required to construct all 225 dams required for the
Bakung and Bangah catchments together. Labour costs for one dam (transport and material
costs excluded) are approximately 150,000 IDR which is equivalent to about 10 Euro. An
annual emission mitigation of 1.5 Mt CO
from restored tropical peatlands is a significant
amount corresponding to 6% of the carbon dioxide emissions by civil aviation in the European
Union in 2006 (UNFCCC 2009), and therefore of interest for carbon crediting on the voluntary
carbon market. This mitigation can be achieved with relatively small efforts and at low costs by
focusing on construction and maintenance of simple dams made of locally available material. In
case oxidation by drainage is limited to the top 50 cm of an active peat layer the total carbon at
stake is 2.1 times higher than that of the aboveground biomass
. This total amount of carbon at
A carbon content of 140.5 t/ha for peat swamp forest (Uryu et al. 2008) and of 58 kg/m³ for peat soils
(Neuzil 1997; Shimada et al. 2001; Supardi et al. 1993) is assumed.
236 Mitig Adapt Strateg Glob Change (2010) 15:223239
stake increases to 22 times the aboveground biomass if no hydrological restoration measures
were implemented and continuous oxidation of the whole 5.4 m thick peat layer was allowed to
take place. Increased awareness of the large amounts of carbon at risk due to tropical peatland
drainage and fires promotes interest in alternative funding mechanisms such as REDD and
carbon credits to safeguard these carbon stocks. Canal blocking in tropical peatlands is not only
a technical but also a social challenge. Illegal logging was, besides gold mining, a main source
of income for people in Central Kalimantan. Now that funding through REDD and carbon
credits becomes a realistic alternative it should also be used to improve livelihoods of local
people. Restoration can only be successful if local communities are actively involved in
planning and implementation of restoration measures as demonstrated in this study by WWF.
Acknowledgments The authors would like to thank Guenola Kahlert, WWF Germany, for financial
support. Special thanks to the WWF Indonesian field team for collecting canal data and to Prof. Hidenori
Takahashi, University of Hokkaido, for the long-term measurements of rainfall and groundwater level at the
test site. We gratefully acknowledge the Global Land Cover Facility (GLCF) for providing SRTM data
without expense, and the US Geological Survey (USGS) for providing Landsat ETM+ imagery.
Open Access This article is distributed under the terms of the Creative Commons Attribution
Noncommercial License which permits any noncommercial use, distribution, and reproduction in any
medium, provided the original author(s) and source are credited.
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... For maintaining ecological and economical sustainability, many scholars (e.g., Miettinen, Shi, & Liew, 2017;Murdiyarso, Hergoualc'h, & Verchot, 2010; highlighted the need for protecting and rehabilitating the degraded PSF in SEA (Erwin, 2009;Jaenicke et al., 2010). Although, numerous ecological restoration initiatives including tree planting had been undertaken in the last few decades; however, scholars (e.g. ...
... Restoration is one of the common use word in the field of ecological restoration that typically involves recovering the damaged or degraded ecosystems to its pre-undisturbed natural state (Erwin, 2009;Jaenicke et al., 2010). Previous studies (e.g. ...
... Hobbs & Cramer, 2008;Aronson et al., 2010) suggested that the main aim of ecological restoration is to regain degraded ecosystem structure and function to its original features by employing a number of restoration measures and techniques. However, in comparison to temperate regions, the understanding and implementation of tropical PSF restoration is still new (Jaenicke et al., 2010;Graham, 2013). For instance, among Southeast Asian countries, Indonesia first introduced peatland restoration activities principally by peatland rewetting through canals blocking only in the early 2000s (Suryadiputra et al., 2005;. ...
Peat swamp forest (PSF) is an ecosystem of global significance. It sequesters and stores atmospheric carbon, regulate hydrological system, provide habitat for many endemic wildlife, and deliver livelihoods support to thousands of local people. Despite these values, during the last several decades PSF have been subject to extensive deforestation and degradation globally. A significant portion (7%) of the Malaysia’s total land mass is PSF that are traditionally managed with the state governance system. However, depletion of this PSF has been continued due to various anthropological causes including intensive logging, drainage, fire, conversion to agriculture, oil pam, settlement, industry etc. Continued depletion of PSF with the centralized governance system (in other ways, here, state forest management, SFM system), and the success of community-based forest management (CBFM) approach in many countries of the world motivated several South-East Asian (SEA) countries to impart changes in their governance system from traditional centralized/state governance approach to CBFM approach. Recently, in Malaysia, specifically State Government of Selangor introduced CBFM approach in the governance of depleted PSF at Raja Musa Forest Reserve (RMFR) in collaboration with Global Environment Centre (GEC, a national non-government organisation). However, the success and/or failure of the newly applied CBFM approach in terms of PSF restoration and community development has not been fully explored yet. The aim of this research was to understand the effectiveness of community participation toward restoration and sustainable conservation of degraded PSF of RMFR in Peninsular Malaysia, with the following objectives: (i) ascertain characteristics of peat, peatland and peat swamp forest, and activities involve in PSF restoration through literature review, (ii) examine the formation and functions of social capital, and the level of community participation in PSF restoration, (iii) analyse the impacts of institutional setting and governance on sustainable conservation and community-based PSF restoration, (iv) assess ecological outcomes of community-based PSF restoration programme, and (v) examine the effect of management regimes of the PSF on local peoples’ socio-economic and environmental benefits. To attain these objectives, the study deployed a pluralistic research approach of social research and ecological (e. g. vegetation survey) study. For social research, both qualitative and quantitative data were collected through a stakeholders’ workshop (with the presence of 49 participants from federal and state Forestry Department, other government agencies, NGOs, local government, academics, local community leaders), four focus group discussions, five key informant interviews and 200 household interviews in four adjacent villages of RMFR. In addition, secondary data was collected from official documents of GEC local office. Building on the concepts and theoretical framework of social capital and level of participation, this research found that some social capital has been developed through forming three local organizations viz. Friends of North Selangor Peat Swamp Forest (FNSPSF), Junior Peatland Forest Ranger (JPFR) and Peatland Forest Ranger (PFR), and integrating another existing organization (Homestay agro-tourism Sungai Sireh) in the restoration programme. In addition, some structural social capital (bonding, bridging and linking) among local community, other similar organizations, NGOs and SSFD have also been developed. But trust (cognitive social capital) among local community, and GEC and SSFD was in question and economic development activities were also very minimal, which demotivated local community and thus showed low level of their participation in the restoration programme. I concluded to reform the organizational structure of local community-based organizations (CBO) by forming two site specific CBOs on local environment namely Forest Conservation and Recreation Village (FCRV), and Forest Restoration Village (FRV), in addition to the current FNSPSF for improving local involvement in the PSF restoration and community development programme. Based on Institutional Analysis and Development framework and concepts of forest property rights (specifically de facto rights), empirical qualitative and quantitative research was carried out on the effectiveness of the local community participation on PSF governance at RMFR; and the impacts of CBFM approach on the de facto rights. I found that CBFM regime had a significant impact on the reduction of exercising de facto rights, which might be related to improved monitoring and enforcement. Further, I identified seven major categories of actors who are actively involved in the PSF restoration programme; however, two actors such as GEC and SSFD play the key role in all governance functions and interact with most of the actors. FNSPSF (key local CBO), have very insignificant role and limited interaction with other actors in the current governance structure. The actors’ participation was enabled by a number of regional, national and local level strategy, policy, and agreements. Although the emergence of the current CBFM showed its effectiveness in the PSF restoration programme; however, limited participation of local community (in particular FNSPSF) in PSF governance posed the major threat to the sustainability of this multi-stakeholder PSF restoration programme. I recommended to put FNSPSF at the centre of the collaborative organizational structure with policy, capacity building and funding support to improve the efficacy and to sustain this newly emergent multi-stakeholder PSF governance. The study on the ecological outcomes of the community-based restoration programme was assessed by collecting data through focus group discussions and key informant interviews (for data on restoration approach), official documents (for data on plantation establishment, water table monitoring and fire incidences) and vegetation survey (for data on planted tree growth and natural regeneration data). Results revealed that PSF rewetting (e.g. improvement of water table) can be achieved with canal blocking and clay dyke construction; further, fire incidences can be reduced through improving water table, providing training on fire drill, creating awareness, and involving local community in forest vigilance. However, annual rate of plantation (about 30 hectares (ha) per year) was found low compared to the total targeted plantation area (1,000 ha). The composition of planted species is limited to only Euodia redlevi with some few other species e.g. Shorea leprosula, Myristica lowiana and M. pruinosa. The average survival rate is 65% with a MAI (mean annual increment) of diameter and height of E. redlevi decreased from younger plantations (3-year) toward older (5-, 7-year). Sixteen regenerating species was identified with an average of 17,798 seedlings ha-1. Natural regeneration was dominated by E. redlevi and only 10.6% of the regeneration could survived to the young tree stage. I recommend to expedite the plantation with diverse potential native species and giving emphasis on post-plantation maintenance. The perceived environmental and socio-economic benefits derived from the community-based restoration programme and local community’s willingness to participate revealed through four focus group discussions, five key-informant interviews and 200 household interviews. I found that CBFM approach has helped to improve some societal and economic benefits including introduction of nature-based recreation, increased income from eco-tourism and community nursery establishment, and nature education and research, and declined PSF conversion to other land uses. On the other hand, perceived environmental benefits including water storage and supply for irrigation, biodiversity and habitat conservation, carbon sequestration capacity of the community-based PSF restoration programme and the material benefits from timber and non-timber forest products (NTFP) supply has not showed any significant improvement yet. This study provides a number of recommendations which highlights institutional such as local level CBOs and multi-stakeholder governance structure, and legal reform, and capacity building of the local community through training and fund streaming to strengthen the community-based PSF governance in Malaysia. In addition, recommendations regarding ecological restoration points out to continue the canal blocking activities with proper maintenance and community patrolling, expedite the annual tree planting rate, increase the number of planted species, and enrichment plantation with diverse species in the planted and assisted natural regeneration forests. I highlight the potential of this study to influence policy space in Malaysia and other SEA countries, as they have similar socio-economic conditions, PSF degradation contexts, and community-based restoration possibilities.
... Process based models have been applied to simulate WTD in tropical peatlands in multiple studies (Wösten et al., 2006;Cobb et al., 2017;Baird et al., 2017;Urzainki et al., 2020). Only few of those have dealt with the question of block performance (Jaenicke et al., 2010;Ishii et al., 2016;Putra et al., 2022). The studies by Ishii et al. (2016) and Jaenicke et al. (2010) did not consider different peat hydraulic properties 50 or weather scenarios, therefore limiting the generalizability of their results. ...
... Only few of those have dealt with the question of block performance (Jaenicke et al., 2010;Ishii et al., 2016;Putra et al., 2022). The studies by Ishii et al. (2016) and Jaenicke et al. (2010) did not consider different peat hydraulic properties 50 or weather scenarios, therefore limiting the generalizability of their results. Putra et al. (2022), on the other hand, presented a good experimental setup to analyze block efficiency, but their simulations were confined to an area of 20 ha. ...
... The WTD difference between 370 the blocked and non-blocked scenarios was, on average, 3 cm at 400 m from the canals, and it was 1 mm at a 1 km distance (see Figure 8). Several studies support this claim (Sutikno et al., 2019(Sutikno et al., , 2020Evans et al., 2019;Putra et al., 2021Putra et al., , 2022Ishii et al., 2016;Jaenicke et al., 2010). Sutikno et al. (2019), using dipwell measurements, claimed that the radius of action of dams in tropical peatlands is around 170 m, and Ishii et al. (2016) found the modelled WTD rise due to blocks to be about 10 cm at a distance of 400 m. ...
Full-text available
Drainage in tropical peatlands increases CO2 emissions, the rate of subsidence, and the risk of forest fires, among other negative environmental impacts. These effects can be mitigated by raising the water table depth (WTD) using canal or ditch blocks. The performance of canal blocks in raising WTD is, however, poorly understood, because the WTD monitoring data is limited and spatially concentrated around canals and canal blocks. This raises the following question: how effective are canal blocks in raising the WTD over large areas? In this work we composed a process-based hydrological model to assess the rewetting performance of 168 canal blocks in a 22000 ha peatland area in Sumatra, Indonesia. We simulated daily WTD over one year using an existing canal block setup and compared it to the situation without blocks. The study was performed across two El-Niño Southern Oscillation (ENSO) scenarios, and four different peat hydraulic properties. Our simulations revealed that while canal blocks had a net positive impact on WTD rise, they lowered WTD in some areas, and the extent of their effect over one year was limited to a distance of about 600 m around the canals. We also show that canal blocks are most effective during dry periods and in peatlands with high hydraulic conductivity. Averaging over all modelled scenarios, blocks raised the annual mean WTD by only 0.9 cm. This value was 2.78 times larger in the dry year than in the wet year (1.39cm versus 0.50 cm), and there was a 2.76 fold difference between the scenarios with the maximum and minimum hydraulic conductivity (1.50 cm versus 0.54 cm). Using a linear relationship between WTD and CO2 emissions, we estimated that, averaging over peat hydraulic properties, canal blocks prevented the emission of 1.03 Mg ha-1 CO2 in the dry year and 0.37 Mg ha-1 CO2 in the wet year.
... An estimated 25.1% of Indonesian peatlands are considered degraded land (Wahyunto & Dariah 2014). Degradation of peatlands causes a decrease in ground water levels and leads to increased oxidation and drainage of peat which can cause fires (Jaenicke et al. 2010). Langner and Siegert (2009) said that fire-affected area in El Niño conditions was usually three times larger than in normal weather conditions. ...
... Nina years (Figure 9) based on the Trenberth's (1997) showing that degraded land is more susceptible to burning than non-degraded land (Langner & Siegert 2009;Jaenicke et al. 2010). ...
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Peat fires have caused carbon emissions and damage to local and regional communities in Indonesia. An effective fire prevention system is required for mitigating climate change and enabling sustainable development of peatlands. This study examined the fire regime in a peatland restoration area in Central Kalimantan in order to assist the establishment of a fire prevention system. The fire regime was analysed using spatial-temporal analysis, land cover change mapping, and logistic regression analysis. Spatial-temporal analysis was done using monthly Niño 3.4 sea surface temperature anomalies, daily rainfall, and MODIS Active Fire (MCD14DL) hotspots from 2006 to 2015. Land cover change was mapped using Landsat imagery from2014, 2015 and 2016. Logistic regression analysis was conducted to identify significant factors that increase fire risk. The temporal analysis showed that the strongest El Niño occurred in 2015, when the region experienced a 140-days drought period. The highest number of hotspots was also observed in this year, with hotspots concentrated in the latter half of drought period. Moreover, spatial analysis using Kernel Density Estimation (KDE) showed fire recur in degraded areas. The logistic regression analysis used topographic and proximity factors, land cover classes, and soil types as independent variables. It showed that fire in 2014 and 2015 was associated with several land cover classes and was related to historical fire occurrence areas based on KDE results. Several area of peatland forests burned in 2015 and occurred at the forest edge areas located near cultivated or degraded land (e.g. shrubland) and oil palm plantations. Based on the results, the fire regime in the study area is characterized by fires that occurring/recurring in relation to climatic conditions, especially drought periods, and are typically located in cultivated or degraded land cover classes. These parameters should be considered in developing a fire prevention system in the restoration area.Rezim Kebakaran Hutan dan Lahan di Area Restorasi Lahan Gambut: Studi dari Kalimantan TengahIntisariKebakaran di lahan gambut menyebabkan emisi karbon dan kerusakan sistem kehidupan masyarakat lokal dan regional. Sistem pencegahan kebakaran yang efektif diperlukan untuk mitigasi perubahan iklim serta mendorong pembangunan lahan dan hutan yang lestari di kawasan gambut. Studi ini meneliti tentang rezim kebakaran hutan dan lahan di suatu kawasan restorasi gambut di Kalimantan Tengah. Rezim kebakaran hutan dan lahan dianalisis menggunakan analisis spasial-temporal, perubahan tutupan lahan, dan regresi logistik. Analisis spasial-temporal menggunakan parameter nilai rata-rata sea surface temperature (SST) bulanan, curah hujan harian, dan hotspot dari MODIS Active Fire (MCD14DL) tahun 2006-2016. Perubahan tutupan lahan dipetakan dengan analisis citra Landsat tahun 2014, 2015 dan 2016. Regresi logistik digunakan untuk menganalisis faktor yang berpengaruh pada peningkatan resiko kebakaran. Analisis temporal terhadap nilai SST tahun 2006-2016 menunjukkan bahwa El- Niño terparah terjadi di tahun 2015 yang memiliki hari tanpa hujan selama 140 hari berturut-turut dan ditemukan titik hotspot terbanyak. Kernel Density Estimation (KDE) digunakan dalam analisis spasial dan hasilnya menunjukkan bahwa kebakaran terjadi dan dapat berulang di area terdegradasi. Regresi logistik menggunakan parameter yang terdiri faktor topografis, kedekatan dengan sungai/kanal, tipe penutupan lahan, serta jenis tanah. Hasil analisis menunjukkan bahwa kebarakan tahun 2014 dan 2015 berhubungan dengan beberapa tipe tutupan lahan di area yang secara historis pernah terbakar berdasarkan analisis KDE, sehingga area tersebut terindikasi telah terdegradasi sebelumnya. Beberapa area hutan di lahan gambut juga mengalami kebakaran pada tahun 2015 khususnya di area tepi hutannya. Berdasarkan hasil, rezim kebakaran di area studi dapat dijelaskan bahwa kebakaran terjadi dan dapat berulang karena pengaruh iklim.
... First, the canal blocking is made in the middle of the peat dome of the protected area (upstream). Then the network is expanded gradually towards the edge of the crown or the cultivation area (downstream) [29], [30], [31], [31], [33] , [34]. ...
... Peat restoration, the mentoring process restoration of degraded or damaged peatlands to their original natural conditions, goes one step further. Unlike the established study of ecological restoration of temperate peatlands [18], [53], knowledge of tropical peatland restoration is still quite limited [36], [35], [1], [29]. However, proper water management is the key to restoration because it minimizes carbon loss due to oxidation and fire and allows plants to grow back [51], [52]. ...
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Tropical peat swamp forest is one of the wetland ecosystems on tropical peatlands with many ecological, economic, and socio-cultural functions. In Indonesia, the peat swamp forest ecosystems have been experiencing deforestation and degradation due to land clearing for plantations and agriculture and forest fires. In Central Kalimantan, especially in the ex-area of the 1 million hectares mega rice project (MRP)n in the 1990s, hydrological restoration is done by blocking the canals. We compared the three methods of canal blocking and the areas without canal blocking and the community’s preference on what form of canal blocking is more beneficial for them. Large canal blocking, medium canal blocking, and small canal blocking had positively affected the groundwater level in the driest month above the fire-prone critical point. In contrast, the locations without blocking exceed the necessary fire-prone water level. Small, large, and medium blocking are equally capable of optimizing the peat soil water table. However, the local communities preferred small blocking over other methods because it was simple, labour-intensive, and improved their livelihood when involved in its construction. The local communities choose the big canal blockings less because they block transportation access in and out of the peat swamp forest.
... Degraded peatland has reduced many ecosystem functions, such as water quality and quantity, biodiversity, and climate regulations (Bonn et al., 2016). Many studies have indicated that huge amounts of carbon have been emitted into the atmosphere due to peatland deforestation and degradation, draining, and repeated fires (Ballhorn et al., 2009;Jaenicke et al., 2010;Hooijer et al., 2014). The removal of above-and below-ground biomass, peat decomposition and oxidation caused by drainage, and peat combustion are all major sources of carbon loss and CO 2 emissions into the atmosphere. ...
... Peatland formation results from flooding or waterlogged conditions, which results in the inhibition of organic materials decompositions, specifically plant materials, due to the oxygen diffusion being impeded by the flooding conditions (Dise, 2009). As a result, peatland drainage is being done by constructing drainage canals to lower the groundwater table, which allows peatland conversion to various land uses such as agriculture, plantation, forestry, and mining (Jaenicke et al., 2010;Rydin et al., 2013). However, the depletion of the groundwater leads to peat oxidation, consolidation, and shrinkage resulting in peat subsidence, carbon emissions, and increased fire hazards, all of which exacerbate climate change (Hooijer et al., 2012;Dohong et al., 2017). ...
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Degraded peatland reduced many ecosystem services such as water quality and quantity, biodiversity, carbon storage, climate regulations and other cultural benefits. Therefore, several initiatives for the restoration of degraded peatland (RDP) have been attempted to restore the ecosystem processes, productivity and services of the degraded peatland to its original natural condition. Notwithstanding the popularity of RDP research among researchers and industry practitioners, a quantitative technique to map a comprehensive survey of the intellectual core and the general body landscape of knowledge on RDP research does not exist. In this study, a scientometric analysis was employed to analyze 522 documents using VOSviewer and CiteSpace. The Web of Science database was used to retrieve bibliographic records using the advanced search “TS (topic) =(‘ drained peatland restoration’ OR ‘drained bog restoration’ OR ‘drained mire restoration’ OR degraded peatland restoration’ OR ‘degraded bog restoration’ OR ‘drained peatland reclamation’ OR ‘drained bog restoration’ OR ‘degraded peatland reclamation’ OR ‘degraded bog reclamation’ OR ‘drained mire restoration’ OR ‘degraded mire reclamation’ OR ‘degraded fen restoration’ OR ‘drained fen reclamation ’). The outcome sought to provide relevant information in RDP research such as (i) publication trends (ii) research outlets (iii) most influential keywords (iv) most influential institutions and authors (v) top influential countries active in RDP research. In addition, four clusters were identified for ascertaining the central theme of RDP research in which cluster one is linked to the central research theme-“impact of drainage on peatland ecosystem services; cluster two focused on the impact of peatland restoration on greenhouse gas emissions; cluster three is associated with peatland restoration and biogeochemical properties and cluster four is related to peatland restoration and species richness. A new research hotspot such as soil respiration was identified via the keywords with the strongest citation bursts. This study will provide the various stakeholders such as industry, journal editors, policymakers and researchers instinctive understanding of the research status and the development frontier of RDP research
... Many severe wildfires occurred in the extremely dry El Niño year (Langner and Siegert, 2009), leading to peatland degradation, which causes irreversible peat subsidence (Wösten et al., 1997). To protect the peatland from wildfires, it is necessary to maintain a high groundwater level in the peat layer, one of the most important restoration measures of tropical peatlands is blocking of drainage canals with dams and thus raising the groundwater level of the surrounding peatland (Suryadiputra et al., 2005), (CKPP, 2008), (Jauhiainen et al., 2008) and (Jaenicke et al., 2010). Rewetting effect by damming were evaluated using remote sensing (Jaenicke et al., 2011). ...
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Carbon emission from the abandoned field of the Mega Rice Project is one of the global environmental problems in Indonesia. To cope with the problem, JICA-JST SATREPS program "Wild Fire and Carbon Management in Peat-forest in Indonesia" will adopt numerical model of groundwater flow for restoring the area. To adopt model, the ground water levels and canal water levels have been measured continuously in Block C of Mega Rice Project, Central Kalimantan to investigate the groundwater movement of in the tropical peat. More than 40 observation wells were installed to measure the fluctuations of the groundwater in an area of 20 km 2. GPS has been used to ensure the accuracy of the position and elevation of each measurement pipe in observation wells. The study showed, in the Block C area, ground water levels of the main canals (Kalampangan Canal and Taruna Canal) were always much lower than the groundwater levels of the surrounding areas. It means that the groundwater levels in the surrounding area of canals changed independently and has negative correlation with the canal water levels. The fluctuation of the water in the canal is also affected by the amount of rainfall and evapotranspiration.
... Efforts to rehabilitate and manipulate the environment where peat grows are (i) inventory, mapping, and land clearing, (ii) construction of gated block canals, water management, drainage irrigation, (iii) keeping them from burning, (iv) acceleration of peak pioneers, (v) making compact mounds previously with wood reinforcement, (vi) planting adaptive seedlings on growing media, backfilling media, reinforced walls and stakes, before the rainy season, (vii) empowering the role of local microbes, (vii) replanting dead seedlings with new plants healthy, (viii) cleaning of discs/mounds of wild vegetation (shrubs, shrubs, herbs, lianas). The effect of canal blocking on the hydrological characteristics of peat is the fluctuation of ground and surface water, water storage, water retention, and greenhouse gas emissions [36]. In areas where weirs are installed, the groundwater level tends to increase significantly and remains at a level of 40 cm (even though it is located upstream). ...
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Moisture and hydrological conditions have a close and fundamental relationship with tropical wetland ecosystems’ existence, characteristics, and function. Peatlands and mangrove ecosystems are wetland ecosystems but both have different unique edaphic characteristics so they are interesting as reference ecosystems. Events like land clearing, drainage, flooding, drought, and fires cause the degradation of peat and mangrove ecosystems in Indonesia. Moisture dynamics and hydro-topography will affect the quality of the land and the environment, so it is very important to study them to provide ecological information for the successful management and restoration of wetland ecosystems. This paper will discuss the role of moisture regimes and hydro-topography in the management of tropical peatlands and mangroves. This study uses a review method by data and information analysis from study reports, field observation notes, and journals simultaneously and in an integrated manner. Moisture regime and hydro-topography conditions on peatlands and mangroves indicate differences in vegetation types and key species. Hydrological characteristics and edaphic conditions are expected to become critical references in the effort to preserve and restore tropical wetland ecosystems, in this case, peatlands and mangrove ecosystems.
... A number of studies have suggested that peat subsidence and loss of carbon are the main consequences of peat oxidization and drainage (Ketcheson and Price, 2011;Hooijer et al., 2012). However, the majority of investigations describe the positive impacts of peat dams, most of all the rapid reestablishment of high water levels and restoration of past hydrological conditions (Jaenicke et al., 2010;Ketcheson and Price, 2011;Gonzalez et al., 2013;Ritzema et al., 2014). Two additional consequences of compaction identified also in this study were a higher soil carbon and nitrogen density observed at the peat dam and drained area, which result from increased peat oxidation and decomposition under the dry conditions. ...
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This study presents the results of field measurements from the Himmelmoor peatland and laboratory incubations, with the aim of examining overall GHG fluxes at the site and comparing fluxes from drained and “rewetted” peat areas. New findings on GHG emissions from dry peat dams are presented for different typical land use types in degraded peatlands under restoration, the properties and GHG fluxes, which are not well covered by the published literature. It was found that all five study sites (peat dam, ditch refilled with peat, extraction area, area rewetted in 2009 and in 2004 with vegetation) differed considerably in their soil-physical and -chemical properties, SOC and total nitrogen, water table level, and vegetation cover. These differences reflect the former management types at the various sites and show that after the first ten years of flooding, peat soils remain strongly affected by the previous environmental conditions under drainage and extraction.
... Tropical peatlands represent only 12% of the world's peatlands (38 Mha); however, they store more than 20% of the world's peatland carbon stocks [1][2][3], and 47% (21 Mha) of global tropical peatlands are located in Indonesia, containing about 65% (57 GtC) of the world's peat carbon [4]. Despite being a global carbon sink, Indonesia's peatlands face extensive degradation and transformation to large-scale plantations and industries, which make them prone to fire and produce a large amount of greenhouse gases (GHGs) [2,5,6]. ...
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Indonesia’s tropical peatlands are one of the world’s largest carbon sinks, and they are facing the threat of extensive degradation and conversion. The Indonesian government is committed to peat restoration. However, restoration is still a costly, top-down approach lacking community participation, and is focused on the 3R scheme (rewetting, revegetation, and revitalization). Peatland restoration businesses are part of the innovative effort to finance this endeavor. Unfortunately, there is not much information available about the pre-conditions required to create a restoration business. This study seeks to understand the enabling conditions for the development of peatland restoration, with a focus on the tamanu oil business, and to assess whether the same situation might apply in the context of the restoration of degraded peatland. PEST analysis is used to describe the macro-environmental factors of the tamanu oil business and its development opportunities in degraded peatlands. Tamanu oil-based peat ecosystem restoration businesses offer good prospects because of the growing it has grown the bioenergy and biomedical markets, and they can cover a larger area of degraded peatland landscape. For tamanu oil businesses to succeed in peat ecosystem restoration, we recommend that policy documents at various levels include tamanu as a priority commodity for peatland restoration and alternative community businesses, followed by planting programs by all stakeholders. The government and social organizations must take positions as initiators and catalysts, establish a significant number and extent of pilot tamanu plantations, and create a mutually supportive business climate between entrepreneurs and peatland managers.
Tropical peatlands are a globally important carbon store. They host significant biodiversity and provide a range of other important ecosystem services, including food and medicines for local communities. Tropical peatlands are increasingly modified by humans in the rapid and transformative way typical of the “Anthropocene,” with the most significant human—driven changes to date occurring in Southeast Asia. This review synthesizes the dominant changes observed in human interactions with tropical peatlands in the last 200 years, focusing on the tropical lowland peatlands of Southeast Asia. We identify the beginning of transformative anthropogenic processes in these carbon-rich ecosystems, chart the intensification of these processes in the 20th and early 21st centuries, and assess their impacts on key ecosystem services in the present. Where data exist, we compare the tropical peatlands of Central Africa and Amazonia, which have experienced very different scales of disturbance in the recent past. We explore their global importance and how environmental pressures may affect them in the future. Finally, looking to the future, we identify ongoing efforts in peatland conservation, management, restoration, and socio-economic development, as well as areas of fruitful research toward sustainability of tropical peatlands.
Technical Report
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The report provides an introduction to the peat swamp forests of Southeast Asia, including a brief overview of past studies, remaining area of this habitat (33 million ha, of which 82% in Indonesia), and a general description of features. It also provides an introduction to floristics and vegetation of Southeast Asian and Sumatran peat swamp forests. It analyses present (2003) condition of Berbak NP in Jambi Province, Sumatra, and assesses the causes of decline. This is followed by an assessment of natural peat swamp forest regeneration in the region and in Western Indonesia. Lastly, it provides various recommendations for approaches to regeneration and restoration of peat swamp forest at Berbak.
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Peat deposits cover 48,000 km2 on the lowlands of Riau Province, Sumatra, Indonesia. Two areas containing typical dome-shaped peat deposits were selected for study. These peat deposits are topographically highest in the geographic interior of the deposit and are drained radially outward by blackwater streams. The source of the water in the peat is precipitation, which exceeds évapotranspiration throughout the year. In cross section, the peat deposits are biconvex; they rest on a nearly level surface, which is within a few meters of sea level. The peat accumulated in the past 5,000 years after stabilization of sea level following the rapid sea-level rise during glacial retreat. In the interior area of the peat deposits, the initial peat accumulation rate was rapid (4-5 mm/yr) for approximately 1,000 years; the rate decreased to less than 2 mm/yr for the past 3,500-4,000 years. These peat deposits have a fibric to hemic texture with slight to moderate humification, a low ash yield, and a low sulfur content; and they contain acid water. A thin layer at the bottom of the deposits tends to be more sapric in texture, more humified, higher in ash yield, higher in sulfur content, and less acid than the overlying peat. Proximate and ultimate analyses of a suite of samples from the interior of each peat deposit show no significant differences in peat quality between the Siak Kanan and Bengkalis Island peat deposits. A primary goal of this study was to evaluate peat resources. The 6.6 × 109 m 3 of peat in the Siak Kanan peat deposit and 3.0 × 10 9 m3 of peat in the Bengkalis Island peat deposit constitute a significant fuel resource. This resource study has contributed a three-dimensional framework and peat quality data that can provide insight into the earliest stage of certain types of coal formation.
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SUMMARY The province of Central Kalimantan contains about three million hectares of peatland, which is one of the largest contiguous areas of tropical peatland in the world. Peat Swamp Forests (PSF) are among the earth's most endangered and least known ecosystems. They have a huge carbon storage capacity but are extremely fragile and liable to disturbance. Local communities have used them extensively for centuries without significant impact on the environment. This changed in 1995 when a programme of massive peatland conversion, the so-called Mega Rice Project (MRP), was initiated with the aim of converting one million hectares of peatland, in Central Kalimantan, Indonesia, into rice fields. Between 1996 and 1998 more than 4000 km of drainage and irrigation channels were constructed in the designated area. Boosted by the El Nino Southern Oscillation (ENSO) episode in 1997, many fires initiated for land clearance purposes spread into pristine forest areas where they continued to burn with great intensity. The newly established drainage and irrigation system aggravated fire impacts, fostering this disaster. The multi-temporal analysis of six LANDSAT TM images acquired between 1991 and 2000 shows extremely high rates of deforestation during this time. Between 1991 and 2000 the area of forest was reduced at the rate of 3.2% per year. If the situation continues there is a very high risk that most of the peat swamp forest resource in Central Kalimantan will be destroyed within a few years with grave consequences for the hydrology, local climate, biodiversity and livelihood of local people. Unless land use policies are changed to control logging and the drainage of the peatland is stopped recurrent fires will lead to an irrecoverable loss of this unique rainforest ecosystem and release of huge amounts of carbon to the atmosphere. Keywords: logging, remote sensing, GIS, land use, deforestation, tropical rainforest, peat swamp forest, Kalimantan, Borneo INTRODUCTION Approximately half of the study site (2 million hectares) around Palangkaraya, the provincial capital of Central Kalimantan, is covered by peatland that supports a natural vegetation of peat swamp forest (Rieley et A,
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Peat fire in tropical peatland not only releases a large amount of carbon into the atmosphere, but also causes significant damage to peatland ecology and the landscape. It is important to understand peat fire and to establish more effective methods to control peat fire. In this paper, the results of field and laboratory research elucidate the combustion and thermal characteristics of peat fire. Field studies were carried out at 9 study plots in actual peat fire areas along the Trans Kalimantan Highway of Central Kalimantan in 2002. Laboratory analyses using a bomb calorimeter and TG-DTA were carried out to obtain low and high ignition temperatures and calorific values of various peat fire fuels. Results of field studies on weather conditions, temperatures in peat layers during fire, patterns of peat fire fronts, peat fire spreading speeds, fuel composition, moisture contents and fuel losses during fires are described in this paper. This study clarified the nature of fire movement and the smoldering process in an actual peat fire in tropical peatland. Based on our results, a more effective method for controlling peat fire can be developed.
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SUMMARY Although tropical peatlands are said to be globally significant carbon sinks that store large amounts of carbon, the data on which this information is based are subject to uncertainty and error. It is estimated that over half of the tropical peatland area is located in Southeast Asia, but there are no up-to-date and accurate measures of the precise location and extent of this resource, especially because of rapid land-use change developments in recent years. When areal extent and thickness data are combined to derive estimates of carbon content and compute the magnitude of tropical peatland carbon pools, uncertainties are compounded. This paper reviews the current state of knowledge and degree of uncertainty on the extent of tropical peatlands globally and their carbon stocks. Recent interest in the carbon storage potential of tropical peatlands, the magnitude of emissions from them and their importance in climate change processes should lead to more detailed field and remote sensing surveys and accurate data inventories in order to improve the state of knowledge.
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Lake Žuvintas, located in southern Lithuania in the Dovinė River basin, is one of the largest lakes and oldest nature reserves in the country. However, changes in the hydrology of the Dovinė River basin, caused by large-scale land reclamation and water management works carried out in the 20th century, have resulted in a significant decrease in the biodiversity of the lake and surrounding wetlands. In order to halt the ongoing deterioration of the lake and wetlands, solutions have to be found at the basin level. Using the SIMGRO model, various measures were therefore analysed to evaluate their impact on the water management in the Dovinė River basin. The results show that it is impossible to fully restore the water dynamics and flow pattern in the Dovinė River to their original state. However, a good measure for improving the hydrological conditions is to block drainage ditches and remove bushes and trees from the wetlands.
Please do not request full text of this old conference abstract. Only preliminary results are presented in it. The full study is available in the following peer reviewed papers; Jauhiainen, J., Takahashi, H., Heikkinen, J.E.P., Martikainen, P.J. & Vasander, H. (2005). Carbon fluxes from a tropical peat swamp forest floor. Global Change Biology 11(10): 1788-1797. DOI: 10.1111/j.1365-2486.2005.001031.x Hirano,T., Jauhiainen, J., Inoue, T. & Takahashi, H. (2009). Controls on the carbon balance of tropical peatlands. Ecosystems 12: 873-887. DOI: 10.1007/s10021-008-9209-1
The visual uniformity of tropical peat swamp forest masks the considerable variation in forest structure that has evolved in response to di¡erences and changes in peat characteristics over many millennia. Details are presented of forest structure and tree composition of the principal peat swamp forest types in the upper catchment of Sungai Sebangau, Central Kalimantan, Indonesia, in relation to thickness and hydrology of the peat. Consideration is given to data on peat geochemistry and age of peat that provide evidence of the ombrotrophic nature of this vast peatland and its mode of formation. The future sustainability of this ecosystem is predicted from information available on climate change and human impact in this region.