Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia. By Dana Veltman

Transcription

1 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia By Dana Veltman

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3 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia Towards a Decision Support System on strategies of sustainable water management Commissioned by: International Institute for Land Reclamation and Improvement / Alterra-ILRI Thesis submitted to Larenstein University of Professional Education In partial fulfilment of requirements for the degree of Master of Science in Land & Water Management By Dana Veltman April 2006

4 iv Velp, The Netherlands

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6 PERMISSION TO USE In presenting this thesis in partial fulfilment of the requirements for a Postgraduate degree, I agree that the Library of this University may make it freely available for inspection. I further agree that permission for copying this thesis in any manner, in whole or in part, for scholarly purposes may be granted by the lecturer(s) who supervised my thesis work, or, in their absence, by the research coordinator of the MSc Land & Water Management. It is understood that any copying, publication, or use of this thesis of parts thereof for financial gain shall not be allowed without my written permission. It is also understood that due recognition shall be given to me and to the University in any scholarly use which may be made of any material in my thesis. Requests for my permission to copy of to make other use of material in this thesis in whole or part should be addressed in writing to: Research Co-ordinator MSc Land & Water Management Larenstein University of Professional Education P.O. Box GB VELP The Netherlands Fax: msclwm@larenstein.nl Keywords library search: agriculture/ animation / Balingian RGC / BOSDA / classification / CO 2 emission / dwarf coconut / forecasting / Geographic Information System / GIS / groundwater flows simulation / Internet / land-use / Malaysia / MODFLOW / oil palm / peat loss / sago / Sarawak / vi

7 scenarios / simulation/ strategies / subsidence/ tropical peat / visualisation / water management / Web design / World Wide Web.

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9 PREFACE About one quarter of the world s tropical peatlands (11 million hectares) occur in Borneo. Due to scarcity of agricultural land, there is an increasing interest to invest in cultivating these swamps. The Government of Sarawak (Malaysia) has identified the populated coastal zone of Sarawak as a major region for agricultural development. In total, 2 million hectares of coastal lowlands will be developed for oil palm, forest plantation, sago, aquaculture, paddy and miscellaneous crops including vegetables. When converting peatlands into land suitable for agriculture, drainage is required. As soon as peatlands are drained, the irreversible process of subsidence commences, resulting in waterlogged growing condition for the crops in the end. Another important issue is the oxidation of peat, which begins as soon as the peatlands are drained. Oxidation emits carbon dioxide (CO 2 ), which may negatively affect the global climate as it contributes to the greenhouse effect. This thesis aims at the development of the Decision Support System on strategies of sustainable water management on tropical peatlands. This thesis contains several land-use scenarios, visual supported by a web-based appendix; the CD-Rom placed on front of this thesis. The DSS should become a useful tool to support planners, decision-makers, and stakeholders who are involved in the development of tropical peatlands at decision-making level. It should offer the opportunity for democratic consultation. This thesis is commissioned by Alterra-ILRI, Institute for Land Reclamation and Improvement. Various projects, in which Alterra-ILRI is involved, aim at the formulation of strategies for implementing sustainable management of the tropical peatlands in Borneo. This research was carried out as the final work in order to obtain my degree from the MSc Land & Water Management. Dana Veltman Velp, April 2006 ix

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11 CONTENTS PERMISSION TO USE...VI PREFACE...IX GLOSSARY... XVII SUMMARY... XIX 1 INTRODUCTION Topic of this research Background Motive for this research Previous research history Social relevance Sustainability Sustainability for agriculture Sustainability for nature Classification of the scenarios Research objective and questions Research objective Research questions Guide to this report STUDY AREA Choice of the study area Landscape Land-use MATERIALS AND METHODS Formulating scenarios by forecasting Principle of projective scenarios Land-use forms in Balingian RGC Formulation of the scenarios Agricultural land-use and groundwater requirements Groundwater depth requirements of crops Establishment of the time span between update moments of the drainage system Subsidence of the ground level The effects of subsidence Calculating of the subsidence The effects of maintaining different growing conditions for crops on subsidence The effects of cultivating different crops on subsidence CO 2 emission The effects of CO 2 emission Calculation of the CO 2 emission due to peat loss Using BOSDA to classify Towards a Decision Support System by means of visualisation xi

12 3.6.1 Visualisation of data The advantage of a web-based Decision Support System on CD-Rom RESULTS CD-ROM to replace the appendices The effects of drainage on groundwater flows Optimum growing circumstances in the first years after applying a drainage system Agricultural land was getting (too) wet after a few years due to subsidence Agricultural land was getting (too) dry for sago Drainage near the sea Drainage of agricultural land affected nature in the surrounding areas Peat loss Subsidence Amounts of peat loss CO 2 emission Classification of the scenarios DISCUSSION CONCLUSIONS AND RECOMMENDATIONS Conclusions Recommendations REFERENCES & LITERATURE...85 EPILOGUE...89 LIST OF TABLES Table 3-1: Land-use by the stakeholders in the formulated scenarios Table 3-2: Colour of the area that is used for agricultural benefit, subdivided by smallholders and plantation owners Table 3-3: Range of the groundwater depths for optimum growing circumstances of crops (Source: Grobbe, 2003, p. 10) Table 3-4: Growing conditions of the cultivated crops used in the scenarios in relation to groundwater depths Table 3-5: Time span between update moments of the drainage system for different growing conditions of oil palm and dwarf coconut Table 3-6: Time span between update moments of the drainage system for different growing conditions of sago Table 3-7: The processes for the phases consolidation, oxidation, and shrinkage leading to subsidence of the ground level (Source: DID, 2001, p. 43) Table 3-8: Stakeholders and their goal with the development of tropical peatlands Table 3-9: Multi Criteria Methods that were available within the programme BOSDA Table 3-10: Measurement scales that can be used in BOSDA(source: programme BOSDA help function) Table 3-11: Criteria on which the scenarios were classified Table 4-1: Amounts of peat loss for the scenarios as a result of subsidence of the ground level after a period of 15 years Table 4-2: Amounts of CO 2 emission for the scenarios as a result of subsidence of the ground level after a period of 15 years xii

13 Table 4-3: Classification of the scenarios in benefit of the stakeholders...73 xiii

14 LIST OF FIGURES Figure 1-1: A facet analysis of topics relevant for setting up a Decision Support System (Source: Chenoweth, 1992, p. 248) Figure 2-1: Location of the river basin of Balingian in Sarawak and the location of the Balingian RGC (Derived from: DID, 2003, basin-map and DID, 2003, agriculture) Figure 2-2: Distribution of peat soils in Sarawak (Source: DID, 2003, peat) Figure 2-3: Typical cross section of a peat dome (Source: Puff, 2003, peat swamp forests) Figure 2-4: Schematic cross section of a peat dome including the transition of forest types (Composed from [Puff, 2003, peat swamp forests] and [Hazebroek et al., 2000, p. 46] Figure 2-5: Forest types of Sarawak. (Source: Hazebroek, 2000, p. 36) Figure 3-1: Schematic model for projective scenarios (Based on the model by Doorn et al., 1978, p. 66) Figure 3-2: Involved stakeholders and their interests Figure 3-3: Water storage method by the Water Management Guidelines (Source: DID, 2001, p.74) Figure 3-4: Formulated scenarios, used in this research Figure 3-5:[Scenario 0] Nature Figure 3-6: [Scenario 1] Present situation Figure 3-7: [Scenario 2] Smallholders Figure 3-8: [Scenario 3A] Smallholders + Oil palm plantation Figure 3-9: [Scenario 3B] Smallholders + Sago plantation Figure 3-10: [Scenario 3C] Smallholders + Oil palm & Sago plantation Figure 3-11: [Scenario 4A] Smallholders + Oil palm plantation (Water storage method) Figure 3-12: [Scenario 4B] Smallholders + Sago plantation (Water storage method) Figure 3-13: Growing conditions of sago in relation to the groundwater depths Figure 3-14: Growing conditions of oil palm and dwarf coconut in relation to the groundwater depths Figure 3-15: The location of the oil palm plantation Figure 3-16: Scenarios with different time spans between the update moments of the drainage system Figure 3-17: Subsidence of the ground level, allowing waterlogged growing circumstances of oil palm, no update moments of the drainage system occurred Figure 3-18: Subsidence of the ground level, maintaining acceptable growing circumstances of oil palm, established with a time span of 4.8 years between update moments of the drainage system Figure 3-19: Subsidence of the ground level, maintaining optimum growing circumstances of oil palm, established with a time span of 2.1 years between update moments of the drainage system Figure 3-20: Different amounts of peat loss, when the growth circumstances differ Figure 3-21: Crops scenarios Figure 3-22: Subsidence of the ground level, allowing acceptable growing circumstances of oil palm, established with a time span of 5 years between update moments of the drainage system Figure 3-23: Subsidence of the ground level, maintaining acceptable growing circumstances for sago, established with a time span of 10 years between update moments of the drainage system Figure 3-24: The cultivation of sago and oil palm results in different amounts of peat loss Figure 3-25: Greenhouse gases cause the warming up of the earth s surface and troposphere (Source: UNFCCC, 2003, p. 2) Figure 3-26: Schematic model of data visualisation for support of natural resource management and decision making (Source: Daniel, 1992, p. 262) Figure 3-27: Mapping an event; (a) by a single map; (b) by a series of maps; (c) with an animation (Source: Kraak et al., 2003, p. 161) Figure 3-28: Primary and secondary perception (Source: Wodtke, 2000, p. 31) xiv

15 Figure 4-1: Growing circumstances maintained optimum for crops in the first years after applying a drainage system, presented by scenario 3A: Smallholders + oil palm plantation...62 Figure 4-2: Creating optimum growing circumstances for the cultivation of crops...62 Figure 4-3: Growing circumstances became (too) wet after a few years after applying a drainage system, presented by scenario 3A: Smallholders + oil palm plantation Figure 4-4: Drainage caused the ground level to subside, resulting in growing circumstances that became (too) wet or even waterlogged Figure 4-5: Growing circumstances became (too) dry for sago in the areas next to oil palm, presented by scenario 3C: Smallholders + oil palm & sago plantation...64 Figure 4-6: Growing circumstances of sago became (too) dry as the groundwater table is draw down by drainage of the adjacent areas, which contained dwarf coconut or oil palm Figure 4-7: The growing circumstances became more waterlogged for crops cultivated at the coastline, presented by scenario 2: Smallholders...65 Figure 4-8:The groundwater table drops below sea level, when land is drained near sea Figure 4-9: To prevent saline intrusion the areas are drained to a depth of 0.05m above sea level...65 Figure 4-10: Drainage of agricultural land affected the surrounding areas also, presented by scenario 3C: Smallholders + oil palm & sago plantation Figure 4-11: By draining agricultural land, nature is also affected...66 Figure 4-12: Location of the cross-section over the peatdome...67 Figure 4-13: Cross-section of the peatdome for scenario 3A (Smallholders + oil palm plantation), showing the subsidence for a period of 15 years Figure 4-14: Scenario 1 (Present situation) compared with scenario 2 (Smallholders), showing the subsidence of the ground level after a period of 15 years Figure 4-15: Scenario 3A (Smallholders + Oil palm plantation) in comparison to 3B (Smallholders + Sago plantation), showing the subsidence of the ground level after a period of 15 years Figure 4-16: Comparison of scenario 3A (Smallholders + Oil palm plantation) with 3B (Smallholders + Sago plantation), showing the ground level after a period of 15 years...69 Figure 4-17: Amounts of peat loss in Mm 3 per year, for each scenario Figure 4-18: Cumulative amount of peat loss in Mm 3, for each scenario Figure 4-19: Amount of CO 2 emission in Mton per year, for each scenario Figure 4-20: Cumulative amount of CO 2 emission in Mton, for each scenario...72 Figure 4-21: Sensitivity of the scenarios...73 Figure 4-22: Classification of the scenarios in benefit of the smallholders who cultivate sago...74 Figure 4-23: Classification of the scenarios in benefit of the smallholders who cultivate dwarf coconut Figure 4-24: Classification of the scenarios in benefit of the plantation owners who cultivate oil palm Figure 4-25: Classification of the scenarios in benefit of the plantation owners who cultivate sago...75 Figure 4-26: Classification of the scenarios in benefit of nature conservationists LIST OF EQUATIONS Equation 3-1: Groundwater depth at point t in time (Source: Grobbe, 2003, p. 50)...43 Equation 3-2: The time spans between update moments of the drainage system, as the groundwater depth no longer met the requirements of a certain grow condition for a particular crop...43 xv

16 Equation 3-3: The time span between update moments of the drainage system for oil palm and dwarf coconut, maintaining acceptable growing conditions of those crops Equation 3-4: The time span between update moments of the drainage system for sago, maintaining acceptable growing conditions of this crop Equation 3-5: Subsidence rate of the ground level in relation to the groundwater depth Equation 3-6: Subsidence of the ground level for a specific moment in time in relation to the groundwater depth Equation 3-7: Ground level at point t in time Equation 3-8: Amount of peat loss at point t in time Equation 3-9: CO 2 emission in relation to the subsidence of the groundlevel LIST OF APPENDICES Consult the CD-Rom, placed in the front of this thesis. xvi

17 GLOSSARY : Sum. Bulk density: The mass of soil per unit volume in an undisturbed condition. CO 2 : Carbon dioxide (a greenhouse gas) Cum.: Cumulative. DID: Department of Irrigation and Drainage, Sarawak, Malaysia. Drainage: Removal of excess surface and subsurface water from land, including removal of soluble salts from the soil, to enhance crop growth. DSS: Decision Support System. LCDA: Land Custody and Development Authority. The LCDA was formed in Its task is to promote plantation agriculture by offering opportunities for joint-venture between landowners and private entrepreneurs. It is also involved in urban development. GHG: Greenhouse gas. Greenhouse gas: gas that contributes to the greenhouse effect. Green house effect: the warming up of the earth s surface, and troposphere. Groundwater: The water beneath the ground level, under conditions where the pressure is equal to, or greater than, atmospheric pressure, and where all the voids are filled with water. m-gl: meter below ground level m+msl: meter above mean sea level MLD: Ministry of Land Development, Sarawak Mm 2 : 1 Mm 2 = 1,000,000 m 2 Mm 3 : 1 Mm 3 = 1,000,000 m 3 msl: mean sea level NRC: Native Customary Rights PORIM: Palm Oil Research Institute Malaysia REpeat: REclamation Policy Evaluation & Analysis Tool. Preceding research, which provided a groundwater simulation model that supported the visualisations for this research. RGC: Rural Growth Centre. xvii

18 SLDB: Sarawak Land Development Board STRAPEAT: Strategies for implementing sustainable management of peatlands in Borneo. The STRAPEAT project aims at the development of guidelines, at the decision-making level, for the sustainable use of coastal peat zones in Sarawak, Malaysia and Kalimantan, Indonesia. Sustainable development: Sustainable development can be defined as a process of social en economic betterment that satisfies the needs and values of all interest groups, while maintaining future options and conserving natural resources and diversity (IUCN, 1989, p.2) UNEP: United Nations Environment Programme. Water table: The locus of points at which the pressure in the groundwater is equal to the atmospheric pressure. The water table is the upper boundary of the groundwater (DID, 2001, p.11). xviii

19 SUMMARY When peatlands are converted into agricultural farmland, drainage is often required causing the vulnerable hydraulic circumstances of peatland to change. The purpose of this study was to proceed with the development of a Decision Support System (DSS) on strategies of sustainable water management, by means of visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia. Background About one quarter of the world s tropical peatlands (11 million hectares) occur in Borneo. Due to scarcity of agricultural land, there is an increasing interest to invest in cultivating these swamps. The Government of Sarawak (Malaysia) has identified the populated coastal zone of Sarawak as a major region for agricultural development. In total, 2 million hectares of coastal lowlands will be developed for oil palm, forest plantation, sago, aquaculture, paddy, and miscellaneous crops including vegetables. It is estimated that between 300,000 and 535,000 hectares of the proposed agricultural area is on peat, located mainly in the Central Region (i.e. Sibu and Sarikei Division). The intensified and unsustainable demand for land, water, marine and coastal resources resulting from the expansion of agriculture and uncontrolled urbanisation lead to increased degradation of natural ecosystems and erode the life supporting systems that uphold human civilisation. Caring for natural resources and promoting their sustainable use is an essential response of the world community to ensure its own survival and well-being. Study area The area of the Balingian Rural Growth Centre (RGC) was chosen to serve as a case study in this research. The Balingian RGC served well as a study area as: 1. The area was situated on peatland, which made it therefore a good example to use for this research, as it had the characteristics of peatsoil. 2. Information and data were available as the site was addressed as a Rural Growth Centre. A development plan was available as well as study reports about crops, land-users, vegetation, inhabitants, etc. 3. For this research, a groundwater simulation model could be used to support the visualisation of land-use scenarios. The model represented the Balingian Rural Growth Centre. Grobbe made this model preceding to this research in his research REpeat (2003). This model was made with the MODFLOW-based programme PMWIN (Grobbe, 2003, p. 31). Land-use The agricultural sector is essentially dualistic, characterised by a smallholder sub-sector and a large-scale plantation sub-sector. The smallholder sub-sector is not uniform and describes a continuum from largely subsistence padi production to heavily commercialised peri-urban horticultural cultivation. The cultivation of oil palm dominates the plantation/estate sub-sector. Oil palm is one of the most important vegetable oil crops in the world. It is a typical crop for the tropics. Among all the promising crops that perform satisfactorily on peat soils, oil palm is the only one that has been grown profitably on large commercial scale in Peninsular Malaysia. Although they require higher production costs, well-managed oil palms growing on peatsoils often yield better than those cultivated on mineral soils. For the Balingian RGC crops cultivated by smallholders are mainly sago and dwarf coconut. Plantations are mainly involved in the cultivation of oil palm and sago. xix

20 Both stakeholders are interested in a sustainable development of agricultural land. Besides the agricultural land-use of peatlands, some areas are assigned as National Parks in benefit of nature. Formulation of the scenarios Land-use scenarios were formulated to support the visualisation of the effects of agriculture on tropical peatlands. Those scenarios were formulated based on the forecasting technique of projective scenarios. A pristine situation, in which a peatdome was left untouched by agriculture, formed the initial stage of which other scenarios were derived. Land-users defined the location and the kind of crop being cultivated. By varying in participating parties and different approaches of maintaining a water-balance, different scenarios were formulated. The following three main stakeholders were indicated to play a part in the formulation of scenarios; (i) smallholders, (ii) plantation owners, and (iii) nature conservationists. Eight scenarios were formulated in which the involvement of the stakeholders varied. Classification of the scenarios Each stakeholder has its own goal with the development of tropical peatlands. Nature conservationists have as goal the preservation of peatland, however smallholders or plantation owners intend to cultivate land to maintain acceptable or optimum growing conditions for their crops over a long period. The programme BOSDA was used as this programme could weigh up a finite set of alternatives and assess the most reasonable alternative (NSCE, 2004, definite). The scenarios were classified in order which scenario guaranteed the interest of the shareholders most. Groundwater depths; a management decision Smart land-use management requires an optimum balance between costs and profits. There has to be a balance between the costs for updating the drainage system, and the profits of crop yields. To what extend a groundwater table is allowed to deviate, is a management decision. Land-users have to decide how much the growing circumstances of crops may become less optimum, and reduce their yields. They have to find a balance between costs and profits. Frequency of updating of the drainage system The difference in time between the renewals of the drainage system also plays an important role in subsidence of the ground level, peat loss and CO 2 emission. If land is drained frequently in order to maintain the groundwater levels in optimum condition, this causes a faster subsidence, greater peat losses and more CO 2 emission than in land where acceptable ground water levels are tolerated. The decision when ground water levels have to be lowered again is a management choice where the costs of renewing the drainage system must be weighed up against the income of the product yield CO2 emission By implementing agricultural land-use on peatland, drainage is necessary. Peat is formed under waterlogged circumstances and it is stable under such circumstances. Once the situation is altered by drainage, the peat would gradually tend to disappear. Micro-organism would feed on the organic material and turn much of the carbon into carbon-dioxide. CO2 is one of the greenhouse gases and contributes to the greenhouse effect: the warming up of the earth s surface and troposphere. The earth s climate is already adjusting to past greenhouse gas emissions. Measurement records indicate an increase of 0.6±0.2 C in global average temperature since the late 19th century. The global average sea level has risen 10 to 20 cm over the past 100 years. It is likely that much of this rise is related to this increase. Drainage near the sea xx

21 Near the coast the farming sector experiences the detrimental effects of salt water intrusion in the event of drainage by gravity. This principle is explained in Eventually, drainage by gravity will become impossible due to a lack of sufficient altitude as the ground level falls as a result of drainage. The influence of drainage on adjacent areas The lowering of the groundwater table has an effect on the surrounding areas. In addition to the fact that drainage causes the subsidence of the ground level, peat loss and CO 2 emission, which has detrimental effects on nature, it is also difficult to combine agriculture and nature in one area. This arises because when lowering the ground water levels in farming areas, this also has a consequence for the surrounding area. A sustainable development of agriculture therefore always conflicts with a sustainable development in favour of nature. It can be noted here that drainage on the top of a peatdome is more damaging than drainage on the edges of a peatdome. The Water storage principle The water storage principle is favourable for the cultivation of crops and less damaging for nature. Due to the shape of and high permeability of the peatdome, an area op top of the peatdome will provide a continuous flow of groundwater towards the rim. The slow release of groundwater during the dry spells can be used to maintain groundwater tables in the lower parts of the peatdome. The best scenario There is no best scenario as it can be approached in several different ways, considering the different goals stakeholders have with the development of tropical peatlands. The goals of the stakeholders conflict with one another. There is not a homogenous outcome of which scenario is best for all involved stakeholders. Decision Support System The next step towards a Decision Support System on strategies of sustainable water management was this research. By visualising the impact of human interference by means of land-use scenarios on tropical peatlands, the DSS should become a useful tool to support planners, decision-makers, and stakeholders who are involved in the development of tropical peatlands at decision-making level. It should offer the opportunity for democratic consultation. A Decision Support System (DSS) can help parties in the planning process, to make a well-fit decision. Three main topics are relevant for setting up a DSS: (i) Bringing together scientists, decision-makers and stakeholders (users); (ii) achieving a scientific enterprise, motivate the environmental decision-making and encourage the communication (purpose); (iii) all within the social, political and organisational context. Visualisation In generating visualisations of environmental management issues, data is connected to the environments they represent only by a complex set of measurement and statistical processes (figure 3-15). Modelling can create possible future situations. Representations are generated entirely by manipulations of data; the environment represented does not (yet) exist. By visualising this data, human perception was enhanced. Humans are good at interpreting visual data (much more so than interpreting numbers, for example), but conventions are still necessary to impart the map s message. It is through mapping that the meaning of a spatial representation of the real world is communicated to users. Maps are models of reality. Maps offer represent complex processes. xxi

22 Animations can be very expressive in explaining these processes. Animations are an excellent means to introduce geo-spatial data s temporal component; the evolution of an event. In this case the representation of the effects of land-use on tropical peatlands. xxii

23 CD-ROM The CD-ROM Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia contains a WEB-based appendix with the results of the land-use scenarios. This CD- ROM replaces the ordinary appendices, which can normally be found at the end of a report. The advantage of the CD-Rom is that this digital publishing of information can be easily spread or even shared global by using the World Wide Web. The advantage of using a web-based design is that it can be extended by adding other disciplines as this medium is getting more accessible. This can increase the collaboration between those who are involved by the development of tropical peatlands. Sustainability As the IUCN stated in 1989: Sustainable development can be defined as a process of social en economic betterment that satisfies the needs and values of all interest groups, while maintaining future options and conserving natural resources and diversity. A good water-balance is an important factor for the growth of crops. Therefore, every form of agriculture on tropical peatlands required drainage, as those areas are in their natural circumstances too wet. The irreversible process of subsidence commences, resulting in peat loss, and CO 2 emission. A sustainable development of tropical peatlands by introducing agriculture is never is benefit of nature. We are obliged to take great care with the development of tropical peatlands, to minimise and compensate the damage. xxiii

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25 1 INTRODUCTION 1.1 Topic of this research When peatlands are converted into agricultural farmland, drainage is often required causing the vulnerable hydraulic circumstances of peatland to change. The purpose of this study was to proceed with the development of a Decision Support System (DSS) on strategies of sustainable water management, by means of visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia. 1.2 Background Motive for this research About one quarter of the world s tropical peatlands (11 million hectares) occur in Borneo. Due to scarcity of agricultural land, there is an increasing interest to invest in cultivating these swamps. The Government of Sarawak (Malaysia) has identified the populated coastal zone of Sarawak as a major region for agricultural development. In total, 2 million hectares of coastal lowlands will be developed for oil palm, forest plantation, sago, aquaculture, paddy, and miscellaneous crops including vegetables. It is estimated that between 300,000 and 535,000 hectares of the proposed agricultural area is on peat, located mainly in the Central Region (i.e. Sibu and Sarikei Division) (DID, 2001, p. i). Owing to a lack of awareness and understanding about sustainable land-use, many peatland development projects fail, resulting in serious environmental degradation and impoverishment of local communities (ALTERRA, 2003, p. 1). A good water-balance is an important factor for the growth of crops. In peatlands, drainage is required as those areas are in their natural circumstances too wet. As soon as peat swamps are drained, the irreversible process of subsidence commences. Another important issue is the oxidation of peat, which begins as soon as the peatlands are drained. Oxidation emits carbon dioxide (CO 2 ), which may negatively affect the global climate (DID, 2001, p. 6). As drainage enhances the circumstances for the agricultural sector, nature experiences the detrimental consequences. In this report, the effects of different land-use scenarios were studied and the consequences compared with each other Previous research history Various projects, in which Alterra-ILRI is involved, aim at the formulation of strategies for implementing sustainable management of the tropical peatlands in Borneo. The STRAPEAT project aims at the development of guidelines, at the decision-making level, for the sustainable use of coastal peat zones in Sarawak, Malaysia and Kalimantan, Indonesia. The project aims to promote wise use of tropical peatlands by integrating biophysical, hydrological and socio-economic data within strategies for sustainable management. It specifically seeks to implement the strategies once they have been formulated for practical use in critical peatland areas Chapter 1: Introduction 25

26 in Borneo. Local research capability will be strengthened enabling peatland managers to better understand and address the different, interrelated processes operating in tropical peatlands. The project will contribute positively to poverty alleviation, protection of the environment, improvement of the quality of life and diminishing health risks (ALTERRA, 2004, STRAPEAT). Grobbe made preceding to this research, a groundwater simulation model in his research REpeat (2003). This model was made for the Rural Growth Centre of Balingian in Central Sarawak, Malaysia. This model simulated the groundwater flows if groundwater levels were altered. In a way, this was a first step to visualise the hydrological consequences of human interference on tropical peatlands. The next step towards a Decision Support System on strategies of sustainable water management was this research in which the abstract outcomes of the REpeat research was translated into more concrete examples. By visualising the impact of human interference by means of land-use scenarios on tropical peatlands, the DSS should become a useful tool to support planners, decision-makers, and stakeholders who are involved in the development of tropical peatlands at decision-making level. It should offer the opportunity for democratic consultation. 1.3 Social relevance Many parties like decision-makers, planners, and stakeholders have their interest in tropical peatland. As the Government of Sarawak has identified the coastal zone of Sarawak as a major region for agricultural development, drainage of peatland will be involved. A Decision Support System, which shows the consequences of drainage, offers the opportunity to support them on a decision-making level. As each party has its own interest in tropical peatland, the DSS provides the opportunity for democratic consultation. A Decision Support System (DSS) can help parties in the planning process, to make a well-fit decision. Three main topics are relevant for setting up a DSS (Chenoweth, 1992, p. 247) as figure 1-1 shows: (iv) Bringing together scientists, decision-makers and stakeholders (users); (v) achieving a scientific enterprise, motivate the environmental decision-making and encourage the communication (purpose); (vi) all within the social, political and organisational context. 26 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

27 Figure 1-1: A facet analysis of topics relevant for setting up a Decision Support System (Source: Chenoweth, 1992, p. 248). Chapter 1: Introduction 27

28 In this framework, this research contributed to the DSS, providing information from the scientific enterprise by means of visualising land-use scenarios and their impact on tropical peatlands. Visualisation is the visual representation of a domain space using graphics, images, animated sequences, and sound augmentation to present the data, structure, and dynamic behaviour of large, complex data sets that represent systems, event processes, object and concepts (Williams et al, 1995, pp ). 1.4 Sustainability The intensified and unsustainable demand for land, water, marine and coastal resources resulting from the expansion of agriculture and uncontrolled urbanisation lead to increased degradation of natural ecosystems and erode the life supporting systems that uphold human civilisation. Caring for natural resources and promoting their sustainable use is an essential response of the world community to ensure its own survival and well-being (UNEP, 2004, natural resources). Sustainable development can be defined as a process of social en economic betterment that satisfies the needs and values of all interest groups, while maintaining future options and conserving natural resources and diversity (IUCN, 1989, p.2) This concept of sustainable development is impossible to establish by developing agriculture on peatlands. Required drainage causes the irreversible process of subsidence and the oxidation of peat thereby emitting CO2. The concept sustainability is therefore also given, seen from the perspective of nature and agriculture Sustainability for agriculture Drainage is a crucial instrument for achieving sustainable agricultural development. In the humid and sub humid tropics, excess water causes crop failure and reduces farmers freedom of choice of crops and varieties. Drainage is essential for sustainable and productive agriculture that will increase the prosperity of the rural population and minimise the risk of loss of life caused by natural disasters (FAO, 2001, p. i). Drainage installation brings significant twin benefits. First, it prevents decline and eventual loss of agricultural lands and helps to maintain fertility. Second, it can lead to increased crop yields through removal of excess moisture, salts and toxic elements from the root zone (FAO, 2001, p. 5). As soon as peat swamps are drained, the irreversible process of subsidence commences, restricting the future drainability of the area and leading ultimately to a shift from gravity drainage to pumped drainage. In the most extreme cases, if pumped drainage is not feasible, financially or otherwise, the peat swamps will have to be returned to nature (DID, 2001, p. 6) Sustainability for nature As the development of agriculture in peatlands requires drainage, the groundwater table is lowered. It disturbs the natural balance, which can harm the biodiversity and the environment of peatlands (DID, 2001, p. 6). Drainage of peatlands causes the irreversible process of subsidence to commence. Another important issue is oxidation of the peat, which begins as soon as the peatlands are drained. Oxidation emits carbon dioxide (CO 2 ), which may negatively affect the global climate (DID, 2001, p. 6). 28 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

29 The only way to arrest subsidence is to re-saturate the peat completely (DID, 2001, p. 34), and the only way to prevent it is to not drain at all. Protection of the environment is imperative for development to remain sustainable (FAO, 2001, p. 17). Sustainable development in peatlands in which agriculture can develop and nature will be preserved can never occur as drainage makes this impossible. For the development of the agricultural sector and the preservation of nature a compromise lies is maintaining the balance between development and conservation. In agricultural development, drainage is a factor that helps to keep the balance. Good drainage practices optimise development of agriculture and conservation of nature. 1.5 Classification of the scenarios Each stakeholder has its own goal with the development of tropical peatlands (see also 1.4). Nature conservationists have as goal the preservation of peatland, however smallholders or plantation owners intend to cultivate land to maintain acceptable or optimum growing conditions for their crops over a long period. The programme BOSDA was used as this programme could weigh up a finite set of alternatives and assess the most reasonable alternative (NSCE, 2004, definite). The scenarios were classified in order which scenario guaranteed the interest of the shareholders most. 1.6 Research objective and questions Research objective The objective of this research project was to develop the next step towards a Decision Support on strategies of sustainable water management by visualising the impact of human interference by means of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia. As described in 1.3, this research should contribute to the DSS, adding information available by the scientific enterprise about the consequences of drainage on tropical peatland for the benefit of the agricultural sector. This goal will be obtained by visualising the consequence of drainage for the agricultural sector and for nature. For the benefit of the agricultural sector, the sustainable development of the cultivation of crops in relation with drainage will be examined. For nature, the irreversible consequences of drainage, resulting in the subsidence of the ground level, peat loss, and CO2 emission will play a part in this research Research questions The central question in this research was: What are the consequences of converting tropical peatlands into agricultural land, causing alterations of the groundwater levels by means of drainage, regarding a sustainable agricultural development and nature preservation? How should those effects be visualised to support the Decision Support System? To give an answer to this central question, the following research questions were formulated: 1. Who are the stakeholders who profit by a sustainable agricultural development? 2. Who are the stakeholders who profit by nature preservation? 3. How can those stakeholders play a role by the formulation of land-use scenarios? Chapter 1: Introduction 29

30 4. What are the results of the alteration of the groundwater level, by means of the scenarios, on: a. The subsidence of the ground level? b. The amount of peat loss? c. The amount of CO 2 emission? d. The consequences for agricultural land-use? e. The consequences for nature? 5. How should the previous questions be visualised in order to contribute to the DSS? 6. What is the most sustainable land-use scenario? 1.7 Guide to this report It is probably not remained unnoticed, as a CD-Rom is placed on the front of this report. Before reading this report, I advise you to consult this CD-Rom to catch a glimpse of the consequence of drainage on tropical peatlands. This CD-Rom is the result of the methods used to obtain a clear visualisation of the consequences of human activities on tropical peatlands. The realisation of the CD-Rom is described in this report. This report contains the following chapters. This chapter is about the topic and background of this research. Chapter 2, in which background information is given about the study area, its natural environment and human interests for those tropical peatlands. The materials en methods used in this research are described in chapter 3. Chapter 4 contains the results, in which the consequences of drainage are lifted out, and goes further into the matter of those consequences. The discussion is placed in chapter 5, followed by the conclusions and recommendations in chapter 6. The report concludes with the list of references and an epilogue, containing a personal concise retrospection on the process of this research. Do not search for the ordinary appendices; consult the CD-ROM. 30 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

31 2 STUDY AREA 2.1 Choice of the study area This research focussed on the effects of agricultural land-use on tropical peatlands in Central Sarawak, Malaysia. To show those effects, a study area was chosen that could serve as a case study. This was the Balingian Rural Growth Centre (RGC). The Balingian RGC served well as a study area as: 4. The area was situated on peatland, which made it therefore a good example to use for this research, as it had the characteristics of peatsoil. 5. Information and data were available as the site was addressed as a Rural Growth Centre. A development plan was available as well as study reports about crops, land-users, vegetation, inhabitants, etc. 6. For this research, a groundwater simulation model could be used to support the visualisation of land-use scenarios. The model represented the Balingian Rural Growth Centre. Grobbe made this model preceding to this research in his research REpeat (2003). This model was made with the MODFLOW-based programme PMWIN (Grobbe, 2003, p. 31). Figure 2-1: Location of the river basin of Balingian in Sarawak and the location of the Balingian RGC (Derived from: DID, 2003, basin-map and DID, 2003, agriculture). The State of Sarawak is divided into 21 major river basins (figure 2-1) for development planning purposes (DID, 2003, basin-map). The Balingian RGC is situated in the river basin of Balingian and is part of the Daro-Mukah coastal zone. The Daro-Mukah coastal zone development plan was made for this region. Agriculture in the project area, as in other parts of Sarawak, is in a transitional phase, adjusting from tradition and subsistence agriculture to more commercial and permanent land-uses which particular emphases on tree crop plantations and cash crops (GOM, 1997, p. ix). Chapter 2: Study area 31

32 The Balingian site has the status of a Rural Growth Centre (RGC). The approach to develop an RGC will result in a more systematic, co-ordinated and integrated manner, than the development of the other rural areas in Sarawak. It is envisaged that the rural sector of Sarawak will be able to compete with the urban centres. In other words, the rural areas will be transformed into attractive places to live and work in. Inevitably, this programme will assist to speed up rural development as well as to eradicate poverty (DID, 2003, RGC). 2.2 Landscape There are about 2.7 million hectares of peatlands in Malaysia. Peatlands account for 8% of the total land area of the country, of which 1.7 million hectares (or 63%) are in the deltas and coastal plains of Sarawak (figure 2-2). Peatlands in Sarawak account for 13% of the state s total land area (DID, 2001, p. 1). Peatlands have global ecological significance, being some of the largest remaining areas of lowland rainforest in South East Asia, that provide the habitat of many endangered species (Alterra, 2003). Figure 2-2: Distribution of peat soils in Sarawak (Source: DID, 2003, peat). The lowland peat swamps occur mainly within 60 km of the coast. Deep peat deposits (>1.5 m) occur around the deltas of the main rivers that drain Sarawak. The depth of the peat near the coast is comparatively shallow. Under the current conditions, the lowland peat swamps of Sarawak are exclusively rain-fed. Along the coast of Sarawak, the tide fluctuates from 2 to 6 meters. The tide influences the levels of rivers and streams, which in turn influence the areas of the peat bodies that border these rivers: the tide influences the hydrology of the swamps. The peat deposits consist of individual peat bodies that may vary from tens to thousands of hectares in size. Usually the peat bodies are lens-shaped (figure 2-3), with a domed surface (DID, 2001, pp. 1-2). 32 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

33 Figure 2-3: Typical cross section of a peat dome (Source: Puff, 2003, peat swamp forests). The oldest deposits in Sarawak were probably formed about 4500 years ago. Peat formation takes place under waterlogged conditions. At the initial stage of formation, peat accumulation is estimated at mm a year. Over time, this accumulation decreases to around 0.5 mm a year at the centre of the peat areas. In most peat basins, the mineral substrata lie below the high water level of the adjacent river, rising above mean sea level only where they start to slope upwards tot meet the river levee (DID, 2001, p. 36). The lowland peat swamps in Sarawak are rain-fed (ombrogeneous), contain a lot of woody materials and the soils have a low mineral content (oligotrophic). They are very acidic (ph < 4) and have a very low mineral/ash content (often below 2%). Their bulk density is below 100 kg/m3 and they have a porosity of 80-90% and a high permeability. The very high average annual rainfall in Sarawak (between 3000 and 5000 mm), the seasonal wet and dry periods, and the wide tidal range all have significant effects on the hydrology of the lowland peat swamps. In its natural state, the water table is always near the surface (DID, 2001, pp. 2-3). Over the last 5400 years, sediment deposited in sheltered bays and within river deltas have been colonised by mangrove forests. This is continuing today and therefore, new land is acquired as the coastal line progresses seawards. This causes the more inland mangrove areas become less frequently flooded. When finally not flooded at all, peat swamps replace the inland mangroves. Figure 2-4: Schematic cross section of a peat dome including the transition of forest types (Composed from [Puff, 2003, peat swamp forests] and [Hazebroek et al., 2000, p. 46]. Chapter 2: Study area 33

34 In their natural state, peat swamps are entirely under forest. Detailed investigation of the flora by Anderson (1937) showed that the forest types occur in a regular sequence form the periphery to the centre (DID, 2002, p. 39). Five types of peat swamp forests gradually replace one another from the rim to the centre of the swamp (figure 2-4). Mixed swamp forest forms the perimeter of the inland swamps but also covers extensive areas of mainly shallow peat near the coast. This forest is replaced by alan forest. This is similar to mixed swamp forest except is it dominated by huge trees of alan (Shorea albida). This forest type usually forms a narrow zone. Nearer to the centre is alan bunga forest with an even canopy consisting almost entirely of alan trees and attaining a height of between 55 and 65 m. This in turn is replaced by padan alan forest, which forms the centre of many swamps. The trees have a pole-like aspect and are relatively small, most with less than 1.8 m girth and 38 m height. Padang kerentum forest only occurs in the centre of the oldest swamps in the Baram delta. This is an open savannah woodland in which all trees are small and stunted, not exceeding a height of 16 m (Hazebroek et al., 2000, p. 46). 2.3 Land-use About 57% of Sarawak is covered with mixed dipterocarp forest. This is considered the richest forest, estimated to contain over 2000 tree species. It represents the peak of rain forest development in Sarawak (Hazebroek, 2000, p. 37). Peat swamp forests are located near the sea. Figure 2-5 also shows large areas of secondary forests, land that is used as farmland and for other land uses. Forest that has been cleared and burnt for farming will eventually revert to secondary forest if there is no further cultivation (Hazebroek, 2000, p. 56). Figure 2-5: Forest types of Sarawak. (Source: Hazebroek, 2000, p. 36). The agricultural sector is essentially dualistic, characterised by a smallholder sub-sector and a large-scale plantation sub-sector. The smallholder sub-sector is not uniform and describes a continuum from largely subsistence padi production to heavily commercialised peri-urban horticultural cultivation. The cultivation of oil palm dominates the plantation/estate sub-sector (SPU, 1992, pp ). Oil palm is one of the most important vegetable oil crops in the world. It is a typical crop for the tropics. Among all the promising crops that perform satisfactorily on peat soils, oil palm is the only one that has been grown profitably on large commercial scale in Peninsular Malaysia. Although 34 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

35 they require higher production costs, well-managed oil palms growing on peatsoils often yield better than those cultivated on mineral soils (DID, 2001, p. 11). In the 1970 s and up to mid 1990 s most of the lands developed for plantations were on mineral soil. Most of the peat areas approved were allied to Land Custody and Development Authority (LCDA) as used for sago plantations. However, as the market price for oil palm increased and research by Palm Oil Research Institute Malaysia (PORIM) indicated reasonably good return from oil palm in peat areas, land applications for oil palm on peatland has dramatically increased (Drahman, 1999, p. 3). Sarawak s large scale land development of plantations has started in the early 1970 s with the opening of oil palm plantations in Miri and Mukah and rubber estates in Meradong by a statutory body, the Sarawak Land Development Board (SLDB) (Drahman, 1999, p. 3). Government agencies were the plantation pioneers in the 1970 s, gradually opening up inaccessible areas and building infrastructure into uncharted territories. Currently the momentum of plantation development has become increasingly driven by the private sector. The private sector is expected to be the engine of growth and to speed up land development activities considering they have the funds, management expertise and market orientation. The State Government will continue to play the active facilitator and co-ordinator role and assist investors with issues on land, labour storage and government matter on law and regulation (Drahman, 1999, p. 3). The smallholder landowners have plenty of land, but it is beyond their capability to develop all of it. They could not realise the full economic potentials of their land due to their lack of capital and expertise on how to develop their land on commercial basis. Those Native Customary Lands, which are subjected to the Native Customary Rights (NCR), can be used for commercial agricultural development by the private sector. On basis of a joint-venture construction, the combination of the land owned by native landowners, and the private sector with its capital and expertise, it is possible to develop the NRC lands for commercial estate (MLD, 1997, pp ). Landowners must identify contiguous block of 5,000 to 10,000 hectares of suitable land such as peat soil or undulating terrain of inland soil with a slope less than 25 degrees (MLD, 1997, p. 26). For the study area Balingian Rural Growth Centre, a development plan was made in This report for the Balingian RGC Development Area contains the consultant s proposals for an implementation of a comprehensive RGC Development Plan of the Sixth and Seventh Malaysian Plan, inclusive of infrastructure and utilities planning and socio-economic activities to sustain the Centre (RMA, 1994, p. 1). This plan sought to capitalise on Balingians comparative advantage in crops such as sago, oil palm and coconut, for which the market is the world market (RMA, 1994, p. 2.3). Integration would also be forged between the estate and smallholder sectors through junction by linkage of estates with smallholder outgrow, the Land Custody and Development Authority (LCDA) would function as the nucleus institution (RMA, 1994, p. 2.3). The main crops that are cultivated in the Balingian RGC are coconut, sago, and oil palm. The cultivation of coconut is situated at the seaside on sandy soils. They are suitable for coconut planting, but large quantities of fertilisers need to be applied to sustain yields (RMA, 1994, p. 3.4). The choice for developing sago plantations is obvious, as this crop is the traditional cultivated in this area. The demand for sago logs has increased tremendously in the last few years (RMA, 1994, p. 3.10). Smallholders, along the riverside, also cultivate sago (RMA, 1994, map 2.2). An oil palm plantation is situated in Balingian RGC. This estate is owned by FELCRA. In 1994, 104 hectares have been planted, and another 240 hectare of NCR land in the vicinity have been earmarked for expansion (RMA, 1994, p. 3.6). Chapter 2: Study area 35

36

37 3 MATERIALS AND METHODS 3.1 Formulating scenarios by forecasting Principle of projective scenarios Land-use scenarios were formulated to support the visualisation of the effects of agriculture on tropical peatlands. Those scenarios were formulated based on the forecasting technique of projective scenarios (fig. 3-1). A pristine situation, in which a peatdome was left untouched by agriculture, formed the initial stage of which other scenarios were derived. Land-users defined the location and the kind of crop being cultivated. By varying in participating parties and different approaches of maintaining a water-balance, different scenarios were formulated. Figure 3-1: Schematic model for projective scenarios (Based on the model by Doorn et al., 1978, p. 66). Projective scenarios give a possible representation of the development into a possible future situation. A scenario is not a prediction. It is rather a way of investigating the implications of particular assumptions about future trends, in this case: the consequences of several land-use forms on tropical peatlands. Depending on the assumptions, a scenario can project growing, stable, or declining trends (UNEP, 2002, p. 4.2). The purpose of creating scenarios was to provide decision-makers with insight of the differences between the scenarios, and to make them more susceptible for the causes (Doorn et al., 1978, p.65) Land-use forms in Balingian RGC The area of the Balingian Rural Growth Centre (RGC) was chosen to serve as a case study in this research ( 2.1). For the formulation of the scenarios of land-use forms on tropical peatlands in Central Sarawak (Malaysia), the same agricultural land-use forms that occur in the Balingian RGC set an example in the research. In the Rural Growth Centre, the agriculture is dualistic, characterised by a smallholder sub-sector and a large-scale plantation sub-sector (see also 2.3). For the RGC crops cultivated by smallholders are mainly sago and dwarf coconut. Plantations are mainly involved in the cultivation of oil palm and sago. Both stakeholders are interested in a sustainable development of agricultural land ( 1.4.1). This makes a sustainable development of peatland in general impossible, as drainage is required causing peat losses ( 1.4). Besides the agricultural land-use of peatlands, some areas are Chapter 3: Materials and methods 37

38 assigned as National Parks (fig 2-5). Although those areas are not situated near the Balingian RGC, they will play an equal role in the formulation of the scenarios, as they are a part of tropical peatlands. This third party was introduced to represent nature conservationists, who profit by the preservation of peatland. Figure 3-2 shows the participating stakeholders. Figure 3-2: Involved stakeholders and their interests. The way those stakeholders use peatland was significant for the formulations of the scenarios. The cultivation of crops by smallholders was restricted to areas at the rim of the peatdome. Plantations were situated on the centre parts of the dome as the private sector has the capacity to develop those areas, in many cases in a joint-venture construction (see also 2.3). Therefore, plantations were bound tot the centre of the peatdome. The centre of the peatdome could be reclaimed on basis of two principles, by situating plantations: 1. On the highest locations of the peatdome. 2. Around the highest locations of the peatdome (fig. 3-3). By leaving this part untouched, it could serve as a water storage area. Due to the shape and high permeability of the peatdome, this area will provide a continuous flow of groundwater towards the rim. The slow release of groundwater during the dry spells can be used to maintain groundwater tables in the lower parts of the peatdome. This principle is described in the Water Management Guidelines (DID, 2001, p. 74). Figure 3-3: Water storage method by the Water Management Guidelines (Source: DID, 2001, p.74). 38 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

39 3.1.3 Formulation of the scenarios As described in the previous paragraph, three main stakeholders were indicated to play a part in the formulation of scenarios; (i) smallholders, (ii) plantation owners, and (iii) nature conservationists. Eight scenarios were formulated (fig. 3-4) in which the involvement of the stakeholders varied. Figure 3-4: Formulated scenarios, used in this research. In supplement on the above-showed figure, table 3-1 shows when a stakeholder participates in a scenario. Nature conservationists have their interest in each scenario, as they pursue to reduce the negative effects of agriculture in tropical peatlands, such as CO 2 emission, peat loss, etc. No scenarios were formulated with only plantations and no participation of smallholders. Smallholders have their interest in each scenario containing agriculture as they occupy the rim in many occasions in reality. Table 3-1: Land-use by the stakeholders in the formulated scenarios. Land-use by stakeholders Scenario A 3B 3C 4A 4B Nature conservationists preserving peatland Smallholders cultivating sago and dwarf coconut Plantation owners cultivating oil palm Plantation owners cultivating sago Indicates the stakeholder participates in the scenario. - Indicates the stakeholder does not participate in the scenario. The figures 3-5 till 3-12 show the location of the areas that are used for agricultural purposes. Coloured areas represent the land-users and the crops they cultivate in that particular area (table 3-2). Table 3-2: Colour of the area that is used for agricultural benefit, subdivided by smallholders and plantation owners. Land-use by stakeholders Colour Smallholders cultivating: - Sago - Dwarf coconut Plantation owners cultivating: - Oil palm - Sago Chapter 3: Materials and methods 39

40 40 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

41 In scenario 0, the pristine situation was left untouched by the agricultural sector. No drainage occurred and the peatdome was left in its natural condition (fig. 3-5). Figure 3-5:[Scenario 0] Nature. Figure 3-6: [Scenario 1] Present situation. Figure 3-7: [Scenario 2] Smallholders. Scenario 1 presented the present situation (fig. 3-6). The location of the areas that were used by smallholders and plantation-owners was based on information provided by the RGC Development Plan Balingian (RMA, 1994). AutoCAD data, which was provided by the research REpeat by Grobbe (see also 2.1), was to assign plots to smallholders or plantation-owners. In scenario 2 (fig. 3-7) local farmers were the only stakeholder that used peatland for agricultural purposes. Figure 3-8: [Scenario 3A] Smallholders + Oil palm plantation. Figure 3-9: [Scenario 3B] Smallholders + Sago plantation. Figure 3-10: [Scenario 3C] Smallholders + Oil palm & Sago plantation. Scenarios 3A (fig. 3-8), 3B (fig. 3-9) and 3C (fig. 3-10) represented plantations that were situated on the highest location of the peatdome. Smallholders were situated at the rim. In those scenarios plantation-owners cultivated crops, such as oil palm, sago, or a combination of both. plantation (Water storage method). Figure 3-12: [Scenario 4B] Smallholders + Sago plantation (Water storage method). Figure 3-11: [Scenario 4A] Smallholders + Oil palm In scenarios 4A (fig. 3-11) and 4B (fig smallholders were represented at the rim and an oil palm or sago plantation around the centre of the peatdome, according to the water storage method (figure 3-3), which was described in Chapter 3: Materials and methods 41

42 3.2 Agricultural land-use and groundwater requirements In peatlands drainage is required as they are in their natural circumstances too wet for agricultural purposes. A high groundwater table reduces the uptake of potash, necessary for the nutrition of crops. Also, a high groundwater table negatively affects the uptake of nitrogen as a lack of aeration retards the formation of nitrate (Kanpathy, 1975, p. 24) Groundwater depth requirements of crops The chosen crops ( 3.1.3) are most suitable for cultivating on peatsoils in Sarawak (DID, 2001, p. 9). Table 3-3 presents the groundwater depth requirements for the chosen crops. Within this range, the crops will have the benefit of the most optimum growing circumstances in relation to the groundwater depth. Table 3-3: Range of the groundwater depths for optimum growing circumstances of crops (Source: Grobbe, 2003, p. 10). Crop Range of the groundwater depth for optimum growing circumstances (m-gl) Remark Minimum Maximum Dwarf coconut (Cocos nucifera) Estimated Oil palm (Elaeis guineensis) Sago (Metroxylon spp.) By keeping groundwater depths within optimum range for those crops, frequent updating of the drainage system is required, as the groundwater depth decreases due to subsidence. Updating of the system is obtained by lowering the groundwater table in order to regain optimum growing conditions. Smart land-use management requires an optimum balance between costs and profits. There has to be a balance between the costs for updating the drainage system, and the profits of crop yields. Therefore, the drainage system is not immediately updated when growing conditions of crops are no longer optimum. Deviating groundwater depths, and therefore less optimal but still acceptable for the growing conditions of crops, were allowed in this research (table 3-4, fig and 3-14). In this research, the conditions waterlogged and too dry were assumed unacceptable. Table 3-4: Growing conditions of the cultivated crops used in the scenarios in relation to groundwater depths. Crop Growing conditions of crops (m-gl) Waterlogged Slightly too wet Optimum Slightly too dry Too dry Sago < 0.15 m m m m > 0.50 m Oil palm & dwarf coconut <0.45 m m m m > 0.90 m 42 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

43 Figure 3-13: Growing conditions of sago in relation to the groundwater depths. Figure 3-14: Growing conditions of oil palm and dwarf coconut in relation to the groundwater depths. To what extend a groundwater table is allowed to deviate, is a management decision. Land-users have to decide how much the growing circumstances of crops may become less optimum, and reduce their yields. They have to find a balance between costs and profits Establishment of the time span between update moments of the drainage system It is needed to adjust the groundwater table, as growing conditions of crops become unacceptable ( 3.2.1). This means that the groundwater table has to lower as conditions become waterlogged, and rise as conditions become too dry. Subsidence of the ground level would solve the problem of growing conditions that are too dry, caused by a low groundwater table. The excessive groundwater depth decreases as the ground level subsides towards the groundwater table. This results in acceptable and optimum growing conditions of crops. As the ground level continues to subside, the groundwater depth decreases to unacceptable shallow depths, resulting in waterlogged conditions. It is needed to update the drainage system when conditions become waterlogged, by lowering the groundwater table. To calculate the groundwater depth for a particular moment in time, equation 3-1 was used in the research REpeat (Grobbe, 2003, p. 50). Equation 3-1: Groundwater depth at point t in time (Source: Grobbe, 2003, p. 50). Groundwater depth at point t in time (m-gl) = Initial groundwater depth (m-gl) * 0.9 t This equation was rewritten into equation 3-2 to retrieve the time span between update moments of the drainage system, as the groundwater depth was no longer within the range for a certain grow condition for a particular crop. Equation 3-2: The time spans between update moments of the drainage system, as the groundwater depth no longer met the requirements of a certain grow condition for a particular crop. Min. required groundwater depth for a condition (m-gl) Time span between update moments = log Initial groundwater depth (m-gl) of the drainage system log 0.9 Chapter 3: Material and Methods 43

44 In table 3-4 the ranges of groundwater depths were given, defining the growing conditions of crops. The equations 3-3 and 3-4 calculates the time span between the update moments of the drainage system for the crops sago, oil palm, and dwarf coconut maintaining acceptable growing conditions. Equation 3-3: The time span between update moments of the drainage system for oil palm and dwarf coconut, maintaining acceptable growing conditions of those crops. Time span between update moments of the 0.45 m-gl drainage system to maintain acceptable growing conditions = log 0.75 m-gl 4.8 years of oil palm and dwarf coconut log 0.9 Equation 3-4: The time span between update moments of the drainage system for sago, maintaining acceptable growing conditions of this crop. Time span between update moments of the 0.15 m-gl drainage system to maintain acceptable growing conditions = log 0.40 m-gl 9.3 years of sago log 0.9 For maintaining the groundwater depth within the range of acceptable growing conditions, the drainage system for oil palm and dwarf coconut had to be updated every 4.8 years. For sago this time span was 9.3 years. Table 3-5: Time span between update moments of the drainage system for different growing conditions of oil palm and dwarf coconut. Growing conditions of oil palm & dwarf coconut Waterlogged Acceptable Optimum Initial groundwater depth (m-gl) Minimum required groundwater depth (m-gl) Time span between update moments (year) Table 3-6: Time span between update moments of the drainage system for different growing conditions of sago. Growing conditions of sago Waterlogged Acceptable Optimum Initial groundwater depth (m-gl) Minimum required groundwater depth (m-gl) Time span between update moments (year) For the calculation of the time span between update moments for waterlogged conditions, the minimum required groundwater depth was set to the limit of 0.05 m-gl. By using equation 3-2 the diminution of the groundwater depth, which is the difference between ground level and the groundwater table, displayed a exponential trend. Therefore, the limit could not be set on 0.00 m- 44 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

45 gl, as the ground level and groundwater table would never be at equal levels when using those equations. Chapter 3: Material and Methods 45

46 3.3 Subsidence of the ground level The effects of subsidence Subsidence is defined in this research as the continuous lowering of the ground level. Subsidence occurs due to drainage of peatlands. Peat soils show characteristically different subsidence behaviour from mineral soils such as clay and sands. Over time, subsidence of mineral soils will stop, first with sands and than with clays. Subsidence of peat soils, however, continues over time at decreasing rates. The subsidence of the ground level of peat due to drainage is divided into three phases; consolidation, oxidation, and shrinkage (DID, 2001, pp ). Table 3-7: The processes for the phases consolidation, oxidation, and shrinkage leading to subsidence of the ground level (Source: DID, 2001, p. 43). Phase Consolidation Oxidation Shrinkage Process A process that results in the compression of permanently saturated peat layers. This very rapid subsidence occurs when virgin peat swamps are drained. In the beginning, it equals approximately the rate at which the groundwater level is lowered. Volume reduction of peat above the groundwater level that results from the loss of organic matter due to decomposition by biochemical processes. Oxidation starts as soon as the peat becomes unsaturated and air enters. The result is CO 2 emission. Volume reduction of peat above the groundwater level due to irreversible loss of water at highly negative water pressures. As table 3-7 shows, subsidence of the ground level contains the phases of consolidation, oxidation, and shrinkage. Other side effects, other than the lowering of the ground level, occur in those phases like the irreversible loss of organic matter and the emission of CO 2. More about CO 2 emission, which occurs in the oxidation phase, is described in 3.4, as this topic deserves more attention, because CO 2 contributes to the greenhouse effect (UNEP, 2002, p. 32.2). Due to subsidence, roots of trees are exposed and they eventually fall over. Peat, in particular deep peat, is therefore a very unsuitable medium for tree crops (Kanapathy, 1975, pp ). The sustainability of various cultivation practices on peat soil is threatened by subsidence of the ground level. Once the groundwater table is lowered to create an optimum groundwater depth for a certain crop, the drained land will subside over time, causing the groundwater depth to decrease. This causes that drained agricultural land loses its required groundwater depth that is required for crops to grow under optimum or even acceptable growing circumstances. Once peat has disappeared, due to subsidence, the mineral subsoil will surface. This will cause the available pyrite to oxidise, forming acid sulphate soils with a very low ph. Acid sulphate soils are problem soils that can be farmed only under conditions of well-controlled water management (DID, 2001, p. 48) Calculating of the subsidence There is a relationship between subsidence of the ground level and the groundwater level. This relationship for peatsoils in Sarawak is formulated in equation 3-5, provided by the Water Management Guidelines (DID, 2001, p. 47). Equation 3-5: Subsidence rate of the ground level in relation to the groundwater depth. Subsidence rate of the ground level (m/year) = 0.1 * Groundwater depth (m-gl) 46 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

47 Equation 3-5 was rewritten into equation 3-6, as it was relevant to know the subsidence of the ground level for a specific moment in time due to drainage of the peat lands. Equation 3-6: Subsidence of the ground level for a specific moment in time in relation to the groundwater depth. Subsidence of the Initial Initial ground level at point t = groundwater depth groundwater depth * 0.9 t in time (m) (m-gl) (m-gl) As equation 3-6 shows, subsidence of the ground level is a result of the alteration of the groundwater depth. Equation 3-7 was formulated to calculate how much the ground level had subsided at a specific moment in time. Equation 3-7: Ground level at point t in time. Ground level Initial Subsidence of the at point t in time = ground level ground level at point t in time (m+msl) (m+msl) (m) Equation 3-8 was formulated to calculate the amount of peat loss for a specific moment in time. Equation 3-8: Amount of peat loss at point t in time. Peat loss Subsidence of the at point t in time = groundlevel at point t in time * m 3 (m 3 ) (m) As appears from the preceding formulas the groundwater level relates to the subsidence of the ground level and amount of peat loss. To show what the consequences are of agricultural activities in tropical peat land areas the groundwater model, made for the Balingian RGC, was used. Grobbe made this model in his research REpeat (2003). This model, made with the aid of the program MODFLOW, simulates the groundwater flows after changing groundwater levels in benefit of the growing circumstances of the crops. Chapter 3: Material and Methods 47

48 3.3.3 The effects of maintaining different growing conditions for crops on subsidence An area situated on top of the peatdome of the Balingian RGC (fig. 3-16) stood example to show the effects of maintaining different growing circumstances for crops. Different time spans between update moments of the drainage system were applied. A peatland area was converted to an oil palm plantation. The land was drained to obtain the requirements for optimum growing circumstances of oil palm. The groundwater table was lowered 0.75m below ground level (see also table 3-4). Three possible scenarios were formulated in which the time span between update moments of the drainage system varied (fig. 3-16). Figure 3-15: The location of the oil palm plantation. Figure 3-16: Scenarios with different time spans between the update moments of the drainage system. In the first scenario no update of the drainage system occurred, and waterlogged growing conditions were allowed for the cultivation of oil palm. After 4.8 years the growing circumstances for oil palm became waterlogged. No updating caused the ground level to subside 0.60m after 15 years (fig. 3-17). 48 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

49 Figure 3-17: Subsidence of the ground level, allowing waterlogged growing circumstances of oil palm, no update moments of the drainage system occurred. In the second scenario a time span of 4.8 years was applied between the update moment, maintaining acceptable growing conditions. This caused the ground level to subside 0.94m after 15 years (fig. 3-18). Drainage update moment Figure 3-18: Subsidence of the ground level, maintaining acceptable growing circumstances of oil palm, established with a time span of 4.8 years between update moments of the drainage system. In the third scenario, the time span between update moments was set at 2.1 years, maintaining optimum growing conditions. As the drainage system was updated more frequently, the ground level subsided most compared with the other two scenarios. After 15 years, the ground level had subsided 1.06m (fig. 3-19). Drainage update moment Chapter 3: Material and Methods 49

50 Figure 3-19: Subsidence of the ground level, maintaining optimum growing circumstances of oil palm, established with a time span of 2.1 years between update moments of the drainage system. As the figures 3-17, 3-18, and 3-19 show, maintaining different growing circumstances results in different amounts of subsidence of the ground level. This is caused by the differences in time spans between the update moments of the drainage system; a frequent draw down of the groundwater table causes an increase in the subsidence rate (Equation 3-5). Figure 3-20 shows the cumulative amounts of peat loss for the scenarios. The biggest amount of peat loss occurred when growing circumstances of oil palm were kept in optimum condition. In the scenario that accepted growing conditions that became slightly too wet, but still acceptable, less peat was lost. The smallest amount of peat was lost, when no updating of the drainage system took place, and the circumstances became waterlogged in the end. Figure 3-20: Different amounts of peat loss, when the growth circumstances differ The effects of cultivating different crops on subsidence An area situated on top of the peatdome of the Balingian RGC (fig. 3-16) stood example to show the effects of cultivating different crops on tropical peatlands. Two scenarios were formulated (fig. 3-21) differing in the kind of cultivated crop. The cultivation of sago was compared with the cultivation of oil palm. Acceptable growing circumstances were allowed (table 3-4). The time span between update moments differ for those crops (tables 3-5, 3-6). 50 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

51 Figure 3-21: Crops scenarios. The time span between the update moments were rounded off for the simplicity of the use of the MODFLOW groundwater simulation model for the Balingian Rural Growth Centre. The time span between the update moments, for the scenario in which oil palm was cultivated, was set at 5 years, maintaining acceptable growing conditions. The groundwater table was lowered 0.75m below ground level. After 15 years, the ground level had subsided 1.09m (fig. 3-22). Drainage update moment Figure 3-22: Subsidence of the ground level, allowing acceptable growing circumstances of oil palm, established with a time span of 5 years between update moments of the drainage system. In the scenario in which sago was cultivated, the time span was set at 10 years between update moments, maintaining acceptable growing conditions. The groundwater table was lowered 0.40m below ground level. After 15 years the ground level had subsided 0.42m (fig. 3-23). Chapter 3: Material and Methods 51

52 Drainage updating moment Figure 3-23: Subsidence of the ground level, maintaining acceptable growing circumstances for sago, established with a time span of 10 years between update moments of the drainage system. As the figures 3-22 and 3-23 show, cultivating different crops results in different amounts of peat loss after 15 years. This is caused by the different frequencies the drainage systems were updated. For maintaining acceptable growing conditions it was needed to update the drainage system of oil palm twice as fast as it was needed for the cultivation of sago. The groundwater table for oil palm was lowered to a depth twice as deep as for sago. Those two factors resulted in a subsidence of the ground level of 1.09m for oil palm, and 0.42m for sago after a period of 15 years. Figure 3-24 shows the cumulative amounts of peat loss for those two scenarios. The cultivation of oil palm resulted in an amount of peat loss 2.5 times bigger than it was the case for sago. Figure 3-24: The cultivation of sago and oil palm results in different amounts of peat loss. 52 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

53 3.4 CO 2 emission The effects of CO 2 emission The main greenhouse gases are water vapour, carbon dioxide, ozone, methane, nitrous oxide, halocarbons and other industrial gases. Apart from the industrial gases, all of those gases occur naturally. Together, they make up less than 1% of the atmosphere. This is enough to produce a natural greenhouse effect that keeps the planet some 30% warmer than it would otherwise be essential for life as we know it (UNEP, 2002, p. 2.2). The dynamics of terrestrial ecosystems depend on interaction between a number of biogeochemical cycles, particularly the carbon cycle, nutrient cycles, and the hydrological cycles. Terrestrial ecological systems, in which carbon is retained in live biomass, decomposing organic matter, and soil, play an important role in the global carbon cycle. Carbon exchanges naturally between these systems and the atmosphere through photosynthesis, respiration, decomposition, and combustion (IPCC, 2000, p. 3). Human activities change carbon stocks in those terrestrial ecological systems and the exchanges between them and the atmosphere through land-use, land-use changes, forestry, and other activities (IPCC, 2000, p. 3). Human activities add an extra release of greenhouse gases into the atmosphere, bringing the natural balance of greenhouse gases out of balance, resulting in the global temperature to rise (UNEP, 2002, p. 1.2). By implementing agricultural land-use on peatland, drainage is necessary. Peat is formed under waterlogged circumstances and it is stable under such circumstances. Once the situation is altered by drainage, the peat would gradually tend to disappear. Micro-organism would feed on the organic material and turn much of the carbon into carbon-dioxide (CO 2 ) (Kanapathy, 1975, p. 24). CO 2 is one of the greenhouse gases (GHG) and contributes to the greenhouse effect: the warming up of the earth s surface and troposphere (figure 3-25) (UNFCCC, 2003, p. 2). The earth s climate is already adjusting to past greenhouse gas emissions. Measurement records indicate an increase of 0.6±0.2 C in global average temperature since the late 19 th century (UNEP, 2002, p. 6.2). The global average sea level has risen 10 to 20 cm over the past 100 years. It is likely that much of this rise is related to an increase of 0.6±0.2 C in the lower atmosphere s global average temperature since 1860 (UNEP, 2002, p. 11.2). Chapter 3: Material and Methods 53

54 Figure 3-25: Greenhouse gases cause the warming up of the earth s surface and troposphere (Source: UNFCCC, 2003, p. 2). Coastal zones are extremely vulnerable, as they have been modified and intensively developed in the recent decades. This made them more vulnerable for higher sea level. Already over 100 years 70% of sandy shorelines have been retreating. Flooding and coastal erosion would worsen (UNEP, 2002, p. 11.2). Rising seas could invade coastal freshwater supplies. Coastal freshwater aquifers may be polluted by saline intrusion as salty groundwater rises. The movement of the saltwater-front up estuaries would affect upriver freshwater-pumping plants, brackish-water fisheries, and agriculture (UNEP, 2002, p. 13.2). It is useful to monitor the CO2 emission and to be aware of the fact that different land-use forms will lead to different amounts of CO2 release. There is a need to strengthen institutional capacity for the collection and collation of data, and for further research to establish local emission factors for national GHG inventories to improve future communication (MOSTE, 2000, p. 97) Calculation of the CO 2 emission due to peat loss CO 2 emission is, like subsidence, a result of drainage of peatlands. There is a relation between those two. By the Water Management Guidelines (2001), it was assumed that an average subsidence rate of 1 cm results in a peat volume reduction of 100 m 3 per hectare per year. A bulk density of 0.1 gram per cm 3 and an average subsidence due to oxidation of 60% will lead to 6 tonnes of decomposed peat per hectare per year. If the carbon content of the peat is 60%, 6 tonnes of decomposed peat will produce 3.6 tonnes of carbon per hectare per year, which will result in a CO 2 emission of tonnes per hectare per year (DID, 2001, p.49). Equation 3-9: CO 2 emission in relation to the subsidence of the groundlevel. CO2 Emission (tonnes/ha/year) = x Subsidence (cm/year) 54 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

55 Therefore, equation 3-9 was used to calculate the CO 2 emission. The amount of subsidence was calculated by means of equation 3-7, and was used for the determination of the amount of CO 2 release. 3.5 Using BOSDA to classify The scenarios, which were formulated in 3.1.3, were classified with the aid of the programme BOSDA. They were classified in order which scenario guaranteed the interest of the shareholders most. Those stakeholders were formulated in Each stakeholder has its own goal with the development of tropical peatlands (see also 1.4). Nature conservationists have as goal the preservation of peatland, however smallholders or plantation owners intend to cultivate land to maintain acceptable or optimum growing conditions for their crops over a long period. Table 3-8 shows the interests in tropical peatlands of the involved stakeholders. Table 3-8: Stakeholders and their goal with the development of tropical peatlands. Stakeholders Goal Smallholders cultivating: - Sago Optimum growing circumstances for the cultivation of sago - Dwarf coconut Optimum growing circumstances for the cultivation of dwarf coconut Plantation owners cultivating: - Sago Optimum growing circumstances for the cultivation of sago - Oil palm Optimum growing circumstances for the cultivation of oil palm Nature Preservation of nature; no subsidence, CO 2 emission, or alteration of the groundwater table, maintaining peat s natural circumstances The programme BOSDA was used to support the Decision Support System as the programme could weigh up a finite set of alternatives and assess the most reasonable alternative. BOSDA contains a number of methods for supporting problem definition as well as graphical methods to support representation (NSCE, 2004, definite). Several Multi Criteria Methods within the programme BOSDA could be used for the classification of the scenarios (table 3-9). The choice for a method depends on the measurement types of the input data of the criteria. Chapter 3: Material and Methods 55

56 Table 3-9: Multi Criteria Methods that were available within the programme BOSDA. Method Measurement type Transparency Weighted summation Quantitative Good Electre 2 method Qualitative Moderately Regime method Only qualitative or qualitative and Moderately quantitative Evamix method Quantitative and qualitative Moderately Table 3-10 provides a survey of the different measurement scales with matching measurement types. Table 3-10: Measurement scales that can be used in BOSDA(source: programme BOSDA help function) Measurement scales Ratio scale Interval scale Monetary scale Ordinal scale Description The meaning/signification of a score measured on a ratio scale is proportional with the height of the score. In other words: a score twice as high, is twice as good or twice as bad. A meaningful zero point is absent. Only the difference between the scores has a meaning. This is a special form of the ratio scale. Scores on this scale are measured in money unit. Only the order between of scores measured is known when scores are being measured on an ordinal scale. No statement can be made about the extension of the difference between the alternatives /+++ scale This scale is used to describe the effects in a qualitative manner. This is a useful method, provided that the results are interpreted with some care. This is a schematic reproduction of the reality, which cannot be unambiguous expressed in numbers. Binary scale Nominal scale On a binary scale, it is exclusively indicated if effects occur or do not occur. Score that are measured on nominal scale cannot be used to classify the alternatives. The scores are not more than a further specification of the alternative, like the name or colour. Measurement type Quantitative Quantitative Quantitative Qualitative Qualitative Qualitative - In table 3-11 goals were converted into scores of which it was possible to obtain data. Those scores were derived from table 3-8 in which the goals for the involved stakeholders are formulated. Table 3-11: Criteria on which the scenarios were classified. 1. Smallholders cultivating sago % cultivated land with acceptable or optimum growing conditions 2. Smallholders cultivating dwarf % cultivated land with acceptable or optimum growing conditions coconut 3. Plantation owners cultivating sago % cultivated land with acceptable or optimum growing conditions 4. Plantation owners cultivating oil palm % cultivated land with acceptable or optimum growing conditions 5. Nature - Subsidence - Peat loss (average) m 3 /are/year - Peat loss (cumulative) m 3 - Land loss land used for agricultural purposes in are - CO 2 emission - CO 2 emission (average) ton/are/year - CO 2 emission (cumulative) ton - Land loss land used for agricultural purposes in are 56 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

57 According to table 3-10, those criteria are on a ratio measurement scale; this is a quantitative measurement type. The weighted summation method was used to classify the scenarios. This method was most suitable for the processing of quantitative measurement types. Chapter 3: Material and Methods 57

58 3.6 Towards a Decision Support System by means of visualisation There are three major abilities of a Decision Support System (DSS): (i) visualisation to illustrate existing and future environmental conditions; (ii) predictive modelling to examine the likely outcomes of change; (iii) and communication to share information and enable the development of jointly held knowledge (Orland et al., 2001, p.143). This research contributes to the DSS providing information from the scientific enterprise by means of visualising land-use scenarios and their impact op tropical peatland Visualisation of data In generating visualisations of environmental management issues, data is connected to the environments they represent only by a complex set of measurement and statistical processes (figure 3-15). Modelling can create possible future situations. Representations are generated entirely by manipulations of data; the environment represented does not (yet) exist (Daniel, 1992, p. 261). By visualising this data, human perception was enhanced. Figure 3-26: Schematic model of data visualisation for support of natural resource management and decision making (Source: Daniel, 1992, p. 262). Humans are good at interpreting visual data (much more so than interpreting numbers, for example), but conventions are still necessary to impart the map s message. It is through mapping that the meaning of a spatial representation of the real world is communicated to users. More recently, faster processing hardware and sophisticated computer graphics, including animation, has led to use of the term visualisation in scientific computing (ViSC) to describe the use of new technology and media to convey the multi-faceted messages of today s mapping (Longley et al., 2003, pp ). For this research, 3D models, maps, and diagrams were used as visual supports. 3D models represent shapes, texture or structure best. If this kind of information is not important, the image could be adequately represented in two dimensions, like a diagram or maps (Romiszowski, 1992, p. 103). Mapping an event in time can be done by means of the following methods (fig. 3-27). Single static map; specific graphic variables and symbols are used to show change in order to represent an event. In figure 3-27 value has been used to represent time. Darker tints indicate older and lighter tints newer development. 58 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

59 Series of maps; The single maps represent snapshots in time. Together the maps make up an event. Change is perceived by looking at the succession of individual maps depicting the event in successive snapshots. Animated map; Change is perceived to happen in a single frame by displaying several snapshots after each other. The difference with the series of maps is that the variations introduced to represent an event have to be deduced not from a spatial sequence but from real movement of the map itself. Within this category one can further distinguish between interactive and non-interactive animations. Examples of the latter are the animated gifs (a repeating sequence of bitmaps) often used in webpages (Kraak, et al., 2003, pp ). Figure 3-27: Mapping an event; (a) by a single map; (b) by a series of maps; (c) with an animation (Source: Kraak et al., 2003, p. 161). Maps are models of reality. Maps often represent complex processes. Animations can be very expressive in explaining these processes. Animations are an excellent means to introduce geospatial data s temporal component; the evolution of an event (Kraak et al., 2003, p.172). In this case the representation of the effects of land-use on tropical peatlands. Primary perception Mind Secondary perception Media Information Figure 3-28: Primary and secondary perception (Source: Wodtke, 2000, p. 31). Chapter 3: Material and Methods 59

60 Digital models can enhance primary perception (our recognition) and aid secondary perception (our interpretation). However, we do the cognitive and conative thinking, as well as judging, in our minds. Each of us determines what information means and what we are going to do about it. We recognise- and attach meanings to- images, written words, symbols, and patterns; we develop a sense of orientation that helps us discover and express new possibilities and make judgements to act upon them (Wodtke, 2000, p. 31). In this research the Geographic Information System-based programme ArcView GIS 3.2 was used to visualise the effects of drainage by means of 2D maps and 3D models. Geographic Information Systems (GIS) link spatial information, such as maps, with databases, such as land-use, and develop spatial models using layers of information. Composing information meeting certain criteria can generate suitable models. GIS links databases to spatial models (Wodtke, 2000, p. 29) The advantage of a web-based Decision Support System on CD-Rom In the past, the production of maps was the realm of cartographers only. Their skills were a guarantee that authoritative maps were produced. The rise of Geographical Information Systems has increased the numbers of those involved in making maps. The revolution of the World Wide Web has even further increased their numbers. This ranges from geo-professionals to anyone having access to this new medium. Maps play a prominent role in the geo-spatial data infrastructure, which itself relies on the WWW to present and disseminate geo-spatial data. The WWW is an ideal platform to combine different multimedia elements with maps. Multimedia is defined by interactive integration of sound, animation, text, and (video)images (Kraak, 2003, pp ). Planners increasingly find that there are numerous ways to present information and that benefits are gained from having a suite of visual and interactive media available to tell their stories. Addressing environmental issues is a problem in networking. Information is widely scattered as well as those trying to gain access. In this case, the Internet is the medium for bringing that information together (Orland et al., 2001, p. 145). The advantage of the CD-Rom is that this digital publishing of information can be easily spread or even shared global by using the World Wide Web. The World Wide Web is the network of sites with browsable pages of hypertext, images and sound which you can select and view by clicking on links. (Branston et al., 1996, pp ). 60 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

61 4 RESULTS 4.1 CD-ROM to replace the appendices The CD-ROM Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia contains a WEB-based appendix with the results of the land-use scenarios. This CD- ROM replaces the ordinary appendices, which can normally be found at the end of a report. The benefit of this digital appendix is that the results are animated. The outcome of the different land-use scenarios contains animated 2D and 3D maps, and histograms. Animation of those outcomes shows the evolution of the consequences of agricultural interferences; the subsidence of the peatdome (in cross-section, 2D and 3D maps), the growing circumstances of the cultivated crops, the CO2 emission per year and cumulative, and groundwater flows. 4.2 The effects of drainage on groundwater flows By implementing agricultural land-use on tropical peatland, drainage is necessary. The groundwater table was lowered, creating optimum growing circumstances for those crops. This alteration resulted in the following side effects: 1. After applying drainage to create the required groundwater depth (see also table 3-3), the growing circumstances of the crops became optimum in the first years ( 4.2.1); 2. Due to subsidence of the ground level, agricultural land becomes wet after a few years, resulting eventually in waterlogged circumstances ( 4.2.2); 3. On locations where sago was cultivated next to oil palm or dwarf coconut, a draw down of the groundwater table caused growing circumstances that were too dry for sago ( 4.2.3); 4. Cultivation of crops near the sea is getting impossible in the end, due to a lack of sufficient altitude of the ground level above sea level ( 4.2.4); 5. Drainage of agricultural land affected nature in the surrounding areas, as the lowering of the groundwater table of farmland caused the groundwater table to lower in those areas as well ( 4.2.5). Chapter 4: Results 61

62 4.2.1 Optimum growing circumstances in the first years after applying a drainage system Start of drainage After 1 year After 2 years Figure 4-1: Growing circumstances maintained optimum for crops in the first years after applying a drainage system, presented by scenario 3A: Smallholders + oil palm plantation. The groundwater table was lowered to create optimum growing circumstances for crops (fig. 4-2). Table 3-3 showed the required groundwater depth for the cultivated crops. After applying a drainage system, the growing circumstances for the cultivated crops maintained in optimum conditions in the first years (fig. 4-1). The areas, in which the growing circumstances are optimum, are green of colour. The natural condition of peatland: Peatland was drained in benefit of agriculture: Figure 4-2: Creating optimum growing circumstances for the cultivation of crops. 62 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

63 4.2.2 Agricultural land was getting (too) wet after a few years due to subsidence Start of drainage After 1 year After 2 years After 3 years Figure 4-3: Growing circumstances became (too) wet after a few years after applying a drainage system, presented by scenario 3A: Smallholders + oil palm plantation. The groundwater was lowered to create optimum growing circumstances for crops (fig. 4-4). As the groundwater table was lowered, the irreversible process of subsidence of the ground level occurred (see also 3.3). This caused the groundwater depth to decrease, resulting in (too) wet or waterlogged growing circumstances of crops (fig. 4-3). The areas turned from optimum growing circumstances (green) into slightly wet conditions (light blue) and even waterlogged conditions (dark blue). The areas that turned into light blue after 3 years contained oil palm and dwarf coconut. The green areas contained sago. The natural condition of peatland: Peatland was drained in benefit of agriculture: Peatland became (too) wet or waterlogged in the end: Figure 4-4: Drainage caused the ground level to subside, resulting in growing circumstances that became (too) wet or even waterlogged. Chapter 4: Results 63

64 4.2.3 Agricultural land was getting (too) dry for sago Start of drainage After 1 year After 2 years After 3 years Figure 4-5: Growing circumstances became (too) dry for sago in the areas next to oil palm, presented by scenario 3C: Smallholders + oil palm & sago plantation. To create optimum growing circumstances for sago, the groundwater table was lowered 0.40m below ground level. For oil palm en dwarf coconut, it was needed to lower the groundwater table 0.75m below ground level. This caused a draw down of the groundwater table in areas were sago was cultivated next to oil palm or dwarf coconut (fig. 4-6). On top of the peatdome a plantation is situated, containing sago at the right side, and oil palm at the left (fig. 4-5). The ground level and groundwater table, which was drawn down by the deeper drainage, did not subside with the same speed. The groundwater depth increased and caused slightly dry (orange) or too dry (red) growing circumstances for sago. The natural condition of peatland: Peatland was drained in benefit of agriculture: Peatland became (too) dry in the end: Figure 4-6: Growing circumstances of sago became (too) dry as the groundwater table is draw down by drainage of the adjacent areas, which contained dwarf coconut or oil palm. 64 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

65 4.2.4 Drainage near the sea Start of drainage After 5 years After 10 years After 15 years Figure 4-7: The growing circumstances became more waterlogged for crops cultivated at the coastline, presented by scenario 2: Smallholders. The ground level declined towards sea level at the coastline. In those areas it was not possible to lower the groundwater table enough to create optimum growing circumstances. Due to subsidence, more land became unsuitable for the cultivation of crops (fig. 4-8). Updating of the drainage system had no effect and land became waterlogged (dark blue). Cultivation of crops near the sea is getting impossible in the end, due to a lack of sufficient altitude of the ground level above sea level (fig. 4-7). The groundwater may get polluted by saline intrusion by salty groundwater ( 3.4.1). It is not desirable to drain salt water, and therefore those areas were drained to a depth of 0.05+msl (fig. 4-9). Figure 4-8:The groundwater table drops below sea level, when land is drained near sea. Figure 4-9: To prevent saline intrusion the areas are drained to a depth of 0.05m above sea level. Chapter 4: Results 65

66 4.2.5 Drainage of agricultural land affected nature in the surrounding areas Land use Start of drainage After 3 years Figure 4-10: Drainage of agricultural land affected the surrounding areas also, presented by scenario 3C: Smallholders + oil palm & sago plantation. The groundwater table was lowered to create optimum growing circumstances for the cultivated crops. This caused a draw down of the groundwater table in the surrounding areas. Therefore, the ground level subsided in the areas that were drained, as well as in the areas that were affected by this drainage (fig. 4-11). The effects of drainage reached far beyond the boundaries of agricultural land, affecting areas, which were reserved for nature preservation (fig. 4-10). The natural condition of peatland: The peatland is drained to benefit agriculture: The surrounded areas were affected by drainage: Figure 4-11: By draining agricultural land, nature is also affected. 66 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

67 4.3 Peat loss Subsidence Drainage is required by the reclamation of tropical peatlands for agricultural purposes. This causes the ground level to subside. This process is described in 3.3. Consult the CD- ROM for the results of drainage on subsidence of the ground level and peat loss for each scenario. This paragraph only explains the basics. Figure 4-12: Location of the cross-section over the peatdome. Figure 4-13 shows a cross-section for the scenario 3B (Smallholders + Sago plantation). Each line represents the subsidence of the ground level with a time span of 1 year between them. The black line represents the initial ground level. A red line marks the ground level every fifth year. As this figure shows, the areas that were used for the cultivation of oil palm or dwarf coconut show more subsidence than the area that was used for the cultivation of sago. Also, areas that were assigned for the preservation of nature are influenced by the drainage of the agricultural land; the ground level in those areas subsided. Figure 4-13: Cross-section of the peatdome for scenario 3A (Smallholders + oil palm plantation), showing the subsidence for a period of 15 years. Chapter 4: Results 67

68 Figure 4-14 compares the ground level after a period of 15 years of scenarios 1 (present situation) with scenario 2 (smallholders). As the figure shows, in scenario 1 subsided the ground level on top of the peatdome almost 0.70m more than it did in scenario 2. This was caused by plantations that were situated at the centre of the peatdome in scenario 1. In scenario 2, the centre of the peatdome was used for nature purposes only. The ground level did subside 0.10m, which was caused by groundwater being withdrawn by agricultural activities situated at the rim of the peatdome. Figure 4-14: Scenario 1 (Present situation) compared with scenario 2 (Smallholders), showing the subsidence of the ground level after a period of 15 years. In figure 4-15, the scenarios 3A (Smallholders + Oil palm plantation) and 3B (Smallholders + Sago plantation) are compared. The ground level on top of the peatdome subsided 0.88m for scenarios 3A. The ground level of scenarios 3B subsided 0.40m. The kind of crop that was cultivated caused the differences between those scenarios. In scenario 3A oil palm was cultivated on top of the peatdome. In scenario 3B sago was cultivated on top of the peatdome. Deeper drainage was required for the cultivation of oil palm, resulting in more subsidence of the ground level after 15 years. 68 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

69 Figure 4-15: Scenario 3A (Smallholders + Oil palm plantation) in comparison to 3B (Smallholders + Sago plantation), showing the subsidence of the ground level after a period of 15 years. In figure 4-16, scenario 3A (Smallholders + Oil palm plantation) and scenario 4A (Smallholders + Oil palm plantation [Water storage]) are compared with each other. Both scenarios contain an oil palm plantation. This plantation is situated on top op the peatdome in scenario 3A, causing the ground level to subside 0.88m. In scenario 4A, the oil palm plantation is still situated near the centre (as the rim of the peadome is reserved for smallholders), but not on the highest region of the peatdome. Therefore, the centre of the peatdome does not subside as much as it is the case in scenario 3A. Figure 4-16: Comparison of scenario 3A (Smallholders + Oil palm plantation) with 3B (Smallholders + Sago plantation), showing the ground level after a period of 15 years Amounts of peat loss The reclamation of land for agricultural purposes differs in each scenario. This had its effect on the amounts of peat loss. Table 4-1 shows the total amounts of peat loss for the scenarios after a period of 15 years. As the area size of land used for agricultural purposes differs in the scenarios, the average amount of peat loss per are per years was given. Table 4-1: Amounts of peat loss for the scenarios as a result of subsidence of the ground level after a period of 15 years. Scenario A 3B 3C 4A 4B Total Mm 3 of peat loss after 15 years Agricultural land in Mm Average m 3 of peat loss per are per year Figure 4-17 shows the amount of peat loss for the scenarios in Mm 3 per year. Every 5 years, the amount of peat loss increased. This was the result of the updating of the drainage system for oil palm and dwarf coconut that occurred with an interval of 5 years. In scenarios that contained bigger areas that were used for the cultivation of oil palm, this effect was amplified; Scenario 1 contained Chapter 4: Results 69

70 the biggest areas of oil palm plantation, resulting in clearly distinguishable peaks. Scenario 3C contained only a small oil palm plantation, which made peaks not clearly distinguishable. The updating of the drainage system every 10 years for sago is also visible. In the scenarios that contained bigger areas that were used for the cultivation of sago, this effect was more clearly to distinguish (scenarios 2, 3B, 3C and 4A). This effects occurred in each scenario, as each scenario contained the cultivation of sago by smallholders. It is not clearly distinguishable for scenarios containing large areas of oil palm, as those lands camouflaged the effect. Figure 4-17: Amounts of peat loss in Mm 3 per year, for each scenario. Figure 4-18 shows the cumulative amount of peat loss for each scenario. Most peat is lost in scenario 1, after a period of 15 years. Scenario 0 shows no sign of any losses, this is because this scenario contained no agriculture activities; this scenario maintained in its natural conditions. 70 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

71 Figure 4-18: Cumulative amount of peat loss in Mm 3, for each scenario. 4.4 CO 2 emission The reclamation of land for agricultural purposes differs in each scenario. This had its effect on the amount of CO 2 emission. Table 4-2 shows the total amount of CO 2 emission for the scenarios after a period of 15 years. As the area size of land used for agricultural purposes differs in the scenarios, the average amount of CO 2 emission per are per years was given. Table 4-2: Amounts of CO 2 emission for the scenarios as a result of subsidence of the ground level after a period of 15 years. Scenario A 3B 3C 4A 4B Total Mton of CO 2 emission after 15 years Agricultural land in Mm Average Mton of CO 2 emission per are per year Figure 4-18 shows the amount of CO 2 emission for the scenarios in Mton per year. Every 5 years, the amount of CO 2 emission increased. This was the result of the updating of the drainage system for oil palm and dwarf coconut that occurred with an interval of 5 years. In scenarios that contained bigger areas that were used for the cultivation of oil palm, this effect was amplified. Scenario 1 contained the biggest areas of oil palm plantation, resulting in clearly distinguishable peaks. Scenario 3C contained only a small oil palm plantation, which made the peaks not clearly distinguishable. The updating of the drainage system for sago every 10 years is also visible. In the scenarios that contained bigger areas that were used for the cultivation of sago, this effect was clearly to distinguish (scenarios 2, 3B, 3C and 4A). This effect also occurred in each scenario, as each scenario contained the cultivation of sago by smallholders. It is not clearly distinguishable for scenarios containing large areas of oil palm, as those lands camouflaged the effect. Chapter 4: Results 71

72 Figure 4-19: Amount of CO 2 emission in Mton per year, for each scenario. Figure 4-20 shows the cumulative amount of CO 2 emission for each scenario. Most CO 2 emitted in scenario 1, after a period of 15 years. Scenario 0 shows no sign of any emission, this is because this scenario contained no agriculture activities; this scenario maintained in its natural conditions. Figure 4-20: Cumulative amount of CO 2 emission in Mton, for each scenario. 72 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

73 4.5 Classification of the scenarios The scenarios, which were formulated in 3.1.3, were classified with the aid of the programme BOSDA. They were classified in order which scenario guaranteed the interest of the stakeholders most. Those stakeholders were formulated in Each stakeholder has its own goal with the development of tropical peatlands (see also 1.4). Nature conservationists have as goal the preservation of peatland, however smallholders or plantation owners intend to cultivate land to maintain acceptable or optimum growing conditions for their crops over a long period. Figure 4-21 shows the sensitivity of the classification of the scenarios, calculated with the aid of the programme BOSDA. The sensitivity shows the hierarchy of the scenarios, taking into account the benefits of the scenario for a specific stakeholder. The figure must be read as followed; For the stakeholder nature conservationists scored scenario 0 (Nature) the best. Scenario 2 came on the second place, followed by scenario 4B, etc. Scenario 3C is the only scenario that met the needs of all involved stakeholders quite well. The scenario scored quite high for each single stakeholder. This scenario came in a (shared) first place for smallholders who cultivated sago or coconut, and for the oil palm plantation. This scenario was not even the worst scenario for the nature conservationists. The lines cross each other often. This means that the goals of the stakeholders conflict with one another. There is not a homogenous outcome of which scenario is best for all involved stakeholders. This sensitivity shows the hierarchy on an ordinal scale (see also table 3-10). Only the order between of scores measured is known when scores are being measured on an ordinal scale. No statement can be made about the extension of the difference between the alternatives. RAN K Smallholder: Sago Smallholder: Dwarf Coconut Figure 4-21: Sensitivity of the scenarios. Plantation: Sago Plantation: Oil palm Nature conservationists PARTY OF INTEREST Scenario 0 Scenario 1 Scenario 2 Scenario 3A Scenario 3B Scenario 3C Scenario 4A Scenario 4B Table 4-4 shows the scores for the scenarios, calculated with the aid of the programme BOSDA, for each stakeholder. All scores are given on a scale from 0 till 1. When a scenario scores 0, it means that this scenario did not meet the goals of this stakeholder at all. If the scenario scores 1, it means that this scenario met the interests for that particular stakeholder completely. The scores between 0 and 1 should be read on a ratio scale; a score measured on a ratio scale is proportional with the height of the score. In other words: a score of 0.44 met the interests of the stakeholder twice as good, as a score of 0.22 did. Table 4-3: Classification of the scenarios in benefit of the stakeholders. Stakeholder Scenario A 3B 3C 4A 4B Smallholders: Sago Chapter 4: Results 73

74 Smallholders: Dwarf coconut Plantation: Sago Plantation: Oil palm Nature conservationists Scenario 0 did not meet the interests of smallholders and plantation owners. This scenario only met the goals of the nature conservationists. Stakeholder: Smallholders who cultivate sago For smallholders who cultivate sago, there are little differences between the scenarios (figure 4-22). Scenario 1 and 4A were slightly less good alternatives for this stakeholder than the other scenarios were. This was caused by the cultivation of oil palm on adjacent plots. Oil palm required deeper drainage, which influenced the growing circumstances for sago (see 4.2.3). Figure 4-22: Classification of the scenarios in benefit of the smallholders who cultivate sago. Stakeholder: Smallholders who cultivate dwarf coconut For smallholders who cultivated dwarf coconut (figure 4-23) not one scenario was optimal. This outcome was strongly affected by the problems of drainage near the sea, which is explained in paragraph The lack of sufficient altitude of the ground level above main sea level was the main cause why growing circumstances for the cultivation of dwarf coconut became too wet. Figure 4-23: Classification of the scenarios in benefit of the smallholders who cultivate dwarf coconut. Stakeholder: Plantation owners who cultivate oil palm The scenarios 1, 3A, 3C, and 4A, obtained an almost optimal score for plantation owners who cultivated oil palm (figure 4-24). The other scenarios had no score, because they did not contain an oil palm plantation. In 3A and 3C, the land maintained in optimum/acceptable growing conditions all the time. The plantation in 4A experienced little effect of the problems of drainage near the sea ( 4.2.4). 74 Visualisation of land-use scenarios on tropical peatlands in Central Sarawak, Malaysia.

75 Figure 4-24: Classification of the scenarios in benefit of the plantation owners who cultivate oil palm. Stakeholder: Plantation owners who cultivate sago The scenarios 1, 3B, 3C, and 4B obtained a score for the plantations on which sago was cultivated (figure 4-25). The other scenarios had no score, because they do not contain a sago plantation. In scenario 3B, the land maintained in optimum/acceptable growing condition for sago all the time. Scenario 1 and 3C experienced the influence of the cultivation of oil palm and dwarf coconut on adjacent plots, which made them less suitable alternatives for this stakeholder (see paragraph 4.2.5). Figure 4-25: Classification of the scenarios in benefit of the plantation owners who cultivate sago. Stakeholder: Nature conservationists The score for nature is given in figure Scenario 0 scored best, because no agricultural activities occurred in this scenario. The other scenarios contained agricultural activities and were therefore more harmful to nature. Scenario 2 (smallholders) is the best alternative, which contains agriculture, closely followed by scenario 4B, containing a sago plantation which is managed on basis of the water storage method (see 3.1.2). The cultivation of sago in the plantations was less harmful than the cultivation of oil palm, because sago did not require such a deep drainage as is required for the cultivation of oil palm. Figure 4-26: Classification of the scenarios in benefit of nature conservationists. Chapter 4: Results 75