Webpages with more detailed information.
Thesis, CO2 adsorption/emissions
Land Classes and Areas
Impact, including CO2 emission
Problems, including CH4 emissions
Water Management System
Swamp Development has
a considerable impact on environment. The most important is the disappearance of the
natural vegetation and its flora and fauna which is unique and in great danger to
disappear completely for large areas in Indonesia.
However the way to
protect the environment is still a subject of controversy. Most of
the Swamp forests will be lost in the near future. This already happened for large areas on Sumatra and Borneo
(Kalimantan). This development will not be stopped. For that reason it would be now more than ever of great
importance to protect the National Parks
in the swamp areas of Indonesia. The most difficult task will be to avoid illegal logging.
That requires constant monitoring (by satelite images and visits to the Parks) and
most important the assistance of the local government.
Beside the loss of an unique flora and fauna there
are other negative impacts. Some impacts of development are important but some of them are less important than
often claimed. I will explain:
Development/reclamation of peat soils
will contribute to greenhouse gas emissions, especially CO2. The main problem
occurs when there is deep drainage with constant groundwater levels deeper than
below surface. Fossil peat will be oxidized and will make a major contribution
to CO2 emissions. Levels of 70 ton CO2 emissions per hectare per year
might be possible. (or 1900 g C/m2 /year, that equals 10 cm/year subsidence of which 60% is
compaction of the peat and 40% is emission by oxidation of fossil peat that has
a bulk density of 0.1g/cm3 and a C content of 0.5 ton C in weight for each 1 ton
of peat). That means also
that when all of the
11 million ha of peat in Indonesia
is reclaimed in this way, there will be a C emission of
209 x 10 12 g C/year, or 2.6% of
total worldwide yearly CO2 emissions from fossil fuel (= 8000 x 1012
g C/year). However when groundwater levels can be reduced to 40 cm below
surface, than emissions per hectare of fossil peat
might be reduced to close to zero.
problem is that in that case only forestry will be suitable with trees that can
grow well in these conditions and not oilpalm. (Oilpalm in these conditions of
40 cm groundwater are still possible but yield will be considerably reduced). It is also essential that a water water
management system will be introduced that allows constant water levels at 40 cm
during dry periods.
This means that the central part on a peat dome should work as a constant
supplier of water towards the borders of the peat dome. Blocking the
canals will not stop the flow through the soil, as permeabilities of peat soil
are high. But with the availability of an undisturbed central peat dome, the
flow of the groundwater from the central dome (called
interflow) will be sufficient to keep waterlevels high during the dry
Only the edges of the peat dome should
be drained to preserve the use of the peat areas as long as possible and
avoid excessive subsidence and a short life-time for the plantation forest.
It should be made clear that the
Nation Wide Survey of coastal and near-coastal swampland in Indonesia (1984), covering 25 million
ha Nation wide, only has found 11 million ha of peat soil with more than 0.7 m peat
thickness. This is considerably less area than presently is claimed in many
publications. The remaining 14 million is according the Nation Wide Survey
mainly occupied land, shallow peat and mineral soil in Tidal Lowlands and deeply
flooded riverplains in coastal and near coastal lowland and saline mangrove
areas. (See also
It can be reasonably assumed that only 2 m peat ,
on average, can be oxidized after which the peat is not drainable by gravity
anymore (2 m peat oxidized will cause more than 4 m drop of land level on deep
peat soils), or only mineral soil remains. That means that the total quantity of
peat soil that in total can be oxidized in Indonesia is 11 x 106 x
104 x 2 = 22 x 1010 m3 peat. This equals 22 x 1010 x 106 x 10-1
= 22 x 10 15 g of peat soil , which is about 11 x
10 15 g C = 11000 Mt C = 11000 x 44/12 = 40333 Mt
CO2. (Total worldwide yearly emissions of fossil fuels is estimated at
29333 Mt CO2= 8000 Mt C)
See also thesis
To see the maps of the Nation Wide
Study of coastal and near-coastal swamplands of Indonesia (1984) click
Nation Wide. This study is still the
most reliable and intensive swampland survey ever be done at Nation Wide level;
concerning: soil types / depth of peat / natural vegetation / agro climate / hydrology and topography
movements / tidal ranges / tidal levels / salinity. Click the map you want to see or
Right Click the map you want to download and use
Save Target as.. (for Windows Internet Explorer) or Save Link as.. (for Mozilla
fossil peat oxidation will contribute to the greenhouse effect. All other
CO2 emissions from the peat soil are part of the CO2 rotation in a forest.
This means that use of gas flux measurements with closed chamber on peat soil
never can make a proper separation between fossil peat emissions and the normal
CO2 rotation of the forest. Better to use the Driessen/Soepraptohardjo (1974)
file; right click link and use Save Target as.. (for Windows Internet
Explorer) or Save Link as.. (for Mozilla Firefox)). This method still needs several years measurements and careful bulk
density measurements each 10-15cm depth until deepest groundwater level (and at
least 3 samples per layer). See at least pages 45 and 46 of the paper where the
distinction is made between subsidence by compaction and by
sponge working of swamps during high rainfall is not valid for peat soil
domes; domes are characteristic for peat swamps in Indonesia. There is no
extra storage possible in the already saturated peat soil and water will
disappear directly to the adjoining lower lying areas, mainly by interflow
(sub-surface flow on a slope). As a prove I can
show you developed tidal lowland areas bordering peat soil domes that could
suffer severe deep flooding during high rainfall when there is no
interception drain and dike bordering the peat soil dome. There are
United Nations Assessment and Coordination Team Mission on Forest Fires,
that says that during high
rainfall the peat works like a sponge: wrong thus!
Peat domes work only as a sponge during dry periods
when it still releases water to lower lying areas. (correctly, luckily, also mentioned
in this paper of the Mission). For more information on peat domes see
webpage: Thesis: peat soils and acid
flat low lying areas of the Tidal Lowlands (usually not peat soil, but clay
soils) there is surface water storage possible from mainly local rainfall during high
rainfall periods. When these areas are developed and used for wetland rice
this storage is still available and probably has even a bigger storage than
before development, including the canals. With the intensive canal system tidal flooding is
possible over a much and much larger areas than before the
development in undisturbed swamp forests and these extra tidal flooded areas
in developed Tidal Lowlands will reduce the flooding problem from the river elsewhere.
Tidal Lowlands are developed for housing and industry, like in Palembang
then a flooding problem is also highly likely because all local flooding storage
potential has disappeared. Still even in this case the Tidal Lowlands have much better
potentials for drainage than the areas more upstream, in the river flooding
areas. Gravity drainage for Tidal Lowlands is still possible during low tide,
but only when the proper drainage system is installed that is needed for the
changes on landuse usually have only a minor influence on river flows in Tidal
Lowlands, a great advantage for the Tidal Lowlands in comparison with the
river flooded areas more upstream! However more flooding might occur
in areas on the border of the Tidal Lowlands upstream.
In natural conditions the groundwater level will
also drop below the pyrite layer in acid sulphate soils during a long dry season, but not
as frequently as in areas developed for agriculture. The reason is that under natural
conditions the soil is often inundated at the end of a wet season, after which it takes a
long time before the water layer will evaporate and the groundwater drops below the pyrite
layer. It might be clear that in developed areas for agriculture such a deep continuous
flooding can never be allowed and therefor pyrite will be exposed more often than under
natural conditions. Frequent exposure of pyrite applies to conditions when only one rice
crop is grown per year, or tree crops are cultivated. After a number of years a new
balance will be found between drop of groundwater level and acidity release when
sufficient leaching will be applied and the pyrite layer will drop to lower levels in the
pollution within a Scheme.The increased pyrite exposure after
reclamation will release large quantities of acids to the direct environment at the
beginning of the wet season, mainly in the adjoining canals.
This leaching is essential to maintain healthy growth of
rice plants. Farmers should be encouraged to improve the leaching conditions
at field level. See Thesis. However the acidity
release will have a negative
effect on fisheries and domestic water uses. Water quality management in the canals is
still an aspect of the infra-structure development which is under-valued in importance.
Much more could be done here by better water management and improving the flushing
capacity of the canals by promoting one-way-flow in the canals based on gate operation
within the system. An important way to tackle the acidity problem is also the introduction
of double connected canals. The
main problem is found deep inside the Schemes far away from the rivers where slackwater
Examples of acidity problems and effects of stagnant groundwater
in the root-zone of the rice-plant.
Acid release to surrounding
environment. In Swamp development often the acidity release to the environment is
mentioned. See also an Australian
Website that warns against the construction of floodgates in the Vietnam Mekong Delta.
My comment: As mentioned above, the proper water
management within a scheme is extremely important. However the effect of the water
management on the environment, surrounding the scheme, is in all cases very limited. The
buffer working of the adjoining water courses is apparently enormous in comparison with
small amounts of acids and other toxic components which are released daily
to the surrounding environment. Years of monitoring in Indonesia proved that no
significant pollution can be found at the borders of the schemes near the rivers and
natural tidal water courses. Based on the data I have seen in Vietnam during a Consultans
Mission to that country, also in Vietnam in the Mekong Delta, before and after the gates
have been constructed, the acidity release from the Rice
growing Schemes to the surrounding estuaries
and tidal environment can not be measured at the borders of the Schemes.
But problems are reported for fish-and shrimp ponds in the mangrove areas.
Here the sudden release of large quantities of acids from bunds and dikes
during and directly after construction may damage the direct environment of
experience and Computer Modelling (Duflow and SMASS) shows that the best
strategy in Indonesia and Vietnam will be leaching from the soil and flushing
in the canals, by one-way flow
in the canals, during the first rains after the dry season.
Pollution from agricultural chemicals. Farmers
apply little land preparation and weeding and prefer direct planting of the seedlings in
plant holes (TOT). The presence of acids causes usually low yields. Farmers do not have a
tertiary field drain system (Micro-system) By the absence of a Micro system there is
little drainage- and flushing-potential to remove the acids. Because of the acidity
problems the rice plants are weak and susceptible to diseases and pests. The absence of
good weed control contributes to rat problem in tidal lands. The wide spread of the
planting season by the lack of manual labour even more contributes to the rat problem.This
all increases the need for herbicides and pesticides with as a result a strongly polluting
effect on the environment. See under web page Thesis, need for mechanisation,
how this problem can be minimised.
Sea-level rise by
greenhouse effect: The possible sea-level rise
in the coming hundred years will have relatively little effect in the swamps of Indonesia
as long the rise is not more than a few decimeter. (say less than 50 cm). The positive
effect will be that the tidal irrigation potential will increase. The negative effect of
an increased need for flood protection in low lying areas will be limited and will not
require large inputs. Most of the developed tidal swamp land is situated above mean high
water level, so dikes will be relatively low.
The statement on the web
Indonesia: vulnerability to climatic change and adaptation that 20 % of
the tidal rice and other swamp uses will be lost by a sealevel rice of 60 cm is
questionable. ( I have also a feeling that the report on the web mixes coastal
land subsidence by intensive urbanization, with possible sealevel rise)
The main worry is for the areas with a
small tidal range, like in West Kalimantan, where the drainage potential may become very
small, especially peatlands
(not used for tidal rice) are in
danger. However the vast majority of the developed rice land in the swamps of Indonesia
has tidal ranges of more than 2 meter. These areas will maintain sufficient drainage
potential after a sea-level rise.
There is also an
unexpected positive impact of swamp development:
Swamp Schemes could be
important for fisheries and waterbird life. In places with good water quality lots of fish can be found
everywhere and during high rainfall periods also in the fields. Large groups of waterbirds
can been seen in many places. The access from the river to land and food through the many
canals will provide for the fish even a much larger habitat than in the original natural
swamp land conditions. Original Swamp Land in Indonesia under natural conditions has not a
significant fish and waterbird life at places away from the river. It is therefore
important that Swamp Scheme Developers will be aware of this new fish and waterbird life
and will take into consideration how to manage the Schemes such that these resources will
not be lost.
The destruction of the Forest in the Forestry
Concessions of South Sumatra province.
Management and Technology Development to protect them. See what happens when you
ignore or oppose!
Two thumbnails of Landsat TM images (Left 26
June 1992, Right 7 May 2000, each covering about 30,000 km2, showing major
parts of the Musi River Basin).The dark green colours on the left image are mainly the
forestry concessions in the Swamps of South Sumatra. On the right image you can see the
forest has gone almost completely. What remains is only secondary low bush land. On the
left image I have drawn the deep
peat areas with a black line, the Swamp Schemes encircled with a red line
and the border between swamp and upland has a purple line.
Swamp Schemes are Government sponsored and
spontaneous local development. Note that 1992 was a very dry
year; the red/purple colours are mainly burnt bush and degraded forest land.
That the forest has gone
in these years is not
the result of Swamp Scheme development, but the result of uncontrolled wood cutting
and wrongly managed forests by big Concession Holders. The Swamps
as a whole have been neglected too
long, because of lack of clear management policies for them. The Environmentalists have been trying
too long to stop the use of swamps in all aspects. The
Developers ignored too long what was happening in the forested Peat Swamps. Better find strategies to manage the swamps as a whole,
including the forested peat lands, the degraded peat lands and the Swamp
More information about the
Musi River Basin and its catchment areas for comparison, see webpage Potentials.
believe in certification to protect the natural environment such as in Berbak
National Park and its buffer zone. (Certification means you pay the stakeholders
when they protect the Natural Environment). May be that might help, but first of
all, I believe, we need a technology in the degraded forests and bush lands in
the swamps that is sustainable and profitable such that nobody will be
interested in the wood of the protected forest areas. Otherwise the wood of the
Natural Forest will remain an attractive income. The combination of
certification and new economic forestry technologies might strengthen the effort
to protect the original natural forest in peat swamp areas.
On the Webpage
Problems I explain the main problems in peat soil: hydrophobic peat and
subsidence of peat soil below sealevel. The problem of hydrophobic peat soil is
solved by planting tree crops instead of annual cropping.
However the problem of subsidence is not solved. Oilpalm needs for
instance a watertable at 60-80 cm below surface for good production. That means
a subsidence of 8-10 cm per year for deep peat! With as a consequence many oilpalm plantations
will be not drainable after 20-30 years and the land will become useless,
putting an extra strain on the remaining protected natural forests! On Webpage
Problems I provide a
suggestion in which direction research should go in my opinion to sustain the
use of peat lands.
information about the problems with peat soils is found on webpage
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