Vice Director and Senior Engineer of the Office of the Executive Committee of the ... is the largest internal drainage Basin in China with a total area of about 1 ...
International Commission on Irrigation and Drainage, 2nd Asian International Conference, Australia. 2004
INTEGRATED MANAGEMENT OF THE TARIM RIVER BASIN, XINJIANG CHINA3 C Lyle1, Mu Gaofeng2 1
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Team leader and water resources specialist for the project ‘Integrated Environmental Management of the Tarim Basin’. Clive Lyle & Associates, 8 Renown St, Balwyn North, Victoria 3104, Australia. Vice Director and Senior Engineer of the Office of the Executive Committee of the Tarim Basin Water Resources Committee The project ‘Integrated Environmental Management of the Tarim Basin’ project was supported by the World Bank and AusAID and was undertaken by Overseas Projects Corporation of Victoria.
ABSTRACT The Tarim River Basin is located in the Xinjiang Uigher Autonomous Region (XUAR) in far Western China and is the largest internal drainage Basin in China with a total area of about 1 million square kilometres with total annual surface runoff of 40 billion cubic metres. The Basin is of similar size to the Murray-Darling Basin of Australia and experiences many similar issues including achieving effective cooperation between semiautonomous jurisdictions responsible for managing the Basin’s resources, returning water to the River for ecological purposes and, better managing land and water salinity. Jurisdictionally, the Tarim Basin includes 5 Prefectures who have delegated responsibilities for managing their respective land, water and environmental resources under the guidance of the XUAR Regional Government. The Tarim Basin is an important part of the XAUR’s economic development. Irrigation is extensive with about 1.5 million ha of irrigated land using 15 Bm3 of surface water and 0.3 Bm3 of groundwater annually. The Basin produces one sixth of China’s cotton as well as grains and fruit. Serious eco-environmental problems have developed over the last 40-50 years. For example, until recently, the lower 300 km of the Tarim River had not received water for 20 years and this seriously degraded the natural ‘green corridor’. Shallow watertables and soil salinity are also endemic in the irrigation areas and surface drains are widely used to drain shallow watertables. The quality of drainage effluent is often of 8-10 g/L and as a result has a major impact on river water quality. The Chinese government and the World Bank have implemented a program of integrated river basin management. AusAID through the Overseas Projects Corporation of Victoria has provided assistance with institutional development, land and water resources planning, and irrigation and salinity management aspects of the program over the last 4 years. This paper describes some of the issues confronting water resources management in the Basin and the approaches being taken. Initiatives that are outlined include the establishment of the Tarim Basin Water Resources Commission and associated management systems, the introduction of a reduced quota on water diversions, reform of rural irrigation agencies, and participatory land and water management planning. INTRODUCTION Human occupation and development of the Tarim Basin has been taking place for several thousands of years with the Basin’s rivers providing the primary corridors for the ancient Silk Road and the oases along the river being the sites of major settlements. In the last 50 years there has been a rapid development of the land and water resources of the Basin. The Chinese and Xinjiang governments have become increasingly conscious of the problems of resource over-exploitation and sustainability over the last decade. With the support of the World Bank and AusAID, Chinese agencies are implementing initiatives to achieve a balance between ecological conditions and, economic and social development. THE TARIM RIVER BASIN AND ITS WATER RESOURCES The Tarim River Basin is 1.02 million square kilometres in area and is located in the Xinjiang Uigher Autonomous Region (XUAR) in far Western China (Figure 1). It is the largest internal drainage basin in China.
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International Commission on Irrigation and Drainage, 2nd Asian International Conference, Australia. 2004 Figure 1: Location of Tarim Basin
Tarim Basin
www.lib.utexas.edu/maps/china
The Basin is bounded to the north, south and west by major mountain ranges with peaks greater than 7,000 m and mountain ranges which are perennially snow covered. The floor of the Basin is about 480,000 square kilometres. The Taklamakan desert which is 60% of the Basin area is the second largest desert in the world and is of low relief with wind blown sand ridges. The Tarim River (Figure 2) which is over 1,300 km long is fed by four major river systems (Hotan, Yerchiang, Kasgar, and Aksu rivers). The Kaidu-Konque river system, is connected to the Tarim river system hydraulically via man-made canals although there have been natural connections previously in past times as river paths have changed with major flood events. The climate in the Basin is classified as Middle Latitude Desert. In the Aksu oasis, during January the average monthly temperature is about -7C and in July it rises to about 26C. Extremes in temperature may range from minus 27C in winter to 39 C in summer. Average rainfall is 48 mm/y and pan evaporation is 1900 mm/y. Upland elevations experience a cooler, more humid climate than that of the plains. There are 1.5 million ha of oasis based irrigated farmland in the Basin. Cotton, wheat, maize are the major crops with some oil seeds, rice and increasingly horticultural produce. The population of the Basin is around 8.8 million with the great majority (85%) being ethnic Uigher peoples. Poverty is a major issue and there are more than 20 national level classified poverty Counties which have average per capita incomes of less than $US 1 per day. Irrigated agriculture accounts for 90% of employment in the Basin. Consequently balancing the sustainable use of the natural resources and ecology whilst improving the living and social conditions of the local people is a huge challenge.
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International Commission on Irrigation and Drainage, 2nd Asian International Conference, Australia. 2004 Figure 2 Schematic Representation of Rivers of Tarim Basin Aksu R.
Kasgar R.
Konque R ALER
YINBAZAR
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Tarim River Yerqiang R.
River Gauging Station Hotan R. Taetima L.
The water resources of the Tarim River are sourced from its tributaries. Annual flow in the major tributaries is shown in Figure 3. Figure 3: Annual Runoff of the Major Tributaries of the Tarim River Tributary Kaidu-Konque Aksu Yerqiang Hotan Other tributaries Total
Annual surface runoff (billion m3) 4.1 8.1 7.5 4.5 15.6 39.8
The natural river flow pattern is shown in Figure 4 and shows low river flows and hence water availability in spring and early summer. This results in a ‘spring drought’ where there is insufficient water for the crops which can be comfortably irrigated during the irrigation season. As a consequence of the spring drought, an ‘excess’ of water during the late autumn-early winter period is used for so-called ‘winter irrigation’ to refill and leach the soil profile before the next growing season. Figure 4: Average seasonal flow at Aler
Aler Average Flow Percentiles for 1984 - 1998 2500
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International Commission on Irrigation and Drainage, 2nd Asian International Conference, Australia. 2004 WATER RESOURCE DEVELOPMENT IN THE TARIM BASIN The water resources of the Tarim Basin are largely unregulated other than small weirs along the rivers where water is diverted for agriculture. Figure 5 shows the significant reduction in river flow at key monitoring sites along the river that has occurred over the last 40 years River flow as a result of increased irrigation. As a result and until recently, the lower Green Corridor (the bottom 300km of river before it reaches its terminal lake system; Taetima Lake) had not received water since the early 1970’s. This led to significant degradation of the local ecology which is dependent on groundwater recharged from the river for its water supply. In 1996, the Lower Green Corridor was estimated to be only 13,300 hectares which is 75% less than its original extent. Figure 5: River flows at Monitoring Points along the Tarim River
RIVER SALINITY There are extensive shallow watertables in the irrigation areas with typically 30% of the soils being saline to some degree. In order to reduce salinisation, leaching of soil profiles and surface drainage are widely used. Surface drains cut specifically to intersect and drain the watertable and which drain to the rivers, cause elevated levels of salinity in the Tarim River, particularly in the low flow periods of spring and early summer (Figure 6). Figure 6: Mineralization along the Tarim River Mineralisation at sites on Tarim River Aler
Mineralisation (g/L)
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International Commission on Irrigation and Drainage, 2nd Asian International Conference, Australia. 2004 The salinity levels reached exceed human health guidelines. Cotton the most common crop is tolerant to salinity and would be little affected at levels of 2-3 g/l, whereas horticultural crops would suffer significantly at levels of 1-2 g/L. INSTITUTIONAL GOVERNANCE OF THE RIVER BASIN The water resources of the Tarim Basin are under the overall responsibility of the XUAR Regional government, however responsibility for planning and operational management of the Basin’s land, water and environmental resources rests with the 5 respective Prefecture governments in the Basin. In order to achieve cooperative management of the Basin’s water resources, the XUAR government has introduced regulations for the cooperative management of the Tarim Basin which involves the XUAR government and each of the Prefecture governments. The Tarim Basin Water Resources Commission (TBWRC) includes representatives from the XUAR agencies (water, agriculture and land management, environment, finance, planning) as well as the leaders of the five prefecture governments in the Tarim Basin. It is supported by an executive which undertakes a coordinating, technical and policy role. The institutional arrangements for the TBWRC are shown in Figure 7 and are broadly styled on the arrangements for the Murray-Darling Basin Commission in Australia. The TBWRC’s overarching principles include coordinated development of the Tarim river resources, balanced economic development and environmental protection; and water resources development which conforms with comprehensive and integrated River Basin planning. As well as implementing the national water law, the TBWRC’s charter includes river basin planning; planning and implementing water sharing and the water diversion quota; organising water licences and collection of water fees; implementing measures to ameliorate the impacts of droughts and floods, water and soil conservation measures, and environmental management; river course management; managing water distribution at the main control points; and examining water development proposals for approval. Figure 7: Institutional Arrangements for the Tarim Basin Initiative XUAR Government
TBWRC
TBWRC Executive Arrangements Executive Committee Office of the Executive Committee Tarim Basin Management Bureau
Prefectures Akesu Bayingol Hotan Kasgar Kisilzu State Farms
Coordination and Consultation Mechanism Water Resources Coordination Committee
RIVER BASIN MANAGEMENT ISSUES There are many water resources and Basin governance issues that the TBWRC is addressing. At this early stage of implementation of the TBWRC institution, the urgent priority is to:
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International Commission on Irrigation and Drainage, 2nd Asian International Conference, Australia. 2004 •
Develop a cooperative and on-going institution which will result in the sustainable management of the Basin’s water and land resources (through the TBRWC institutional arrangements)
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Implementing new water sharing arrangements (a quota for water diversions) and further developing the Masterplan for the Tarim River including improving environmental flows and ecological conditions along the lower Tarim River in particular, whilst also protecting other river reaches. Increasing the efficiency of water use in irrigation areas to improve economic, social and environmental conditions in an environment of decreasing water allocations.
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Quota on Water Diversions A quota on water diversions for irrigation by Prefectures was introduced in 1999. The objective of the quota is to improve the Tarim River environment, raise groundwater to a depth of 4 metres of the soil surface within 1 kilometre along the Lower Green corridor so that it can be accessed by the riparian vegetation and, to deliver water to Taetima lake which is the terminal lake of the river system. The new quota amounted to significant reductions in water allocated to irrigated agriculture in the order of 20- 30% in some Prefectures. This was understandably a very contentious issue at the time which nevertheless, was negotiated through the TBWRC institution. The quota comprises allowable monthly diversion limits. Quota implementation is closely monitored and ‘real’ time reports of monthly diversions are prepared and, where the monthly quota is not met, official notices are issued to the offending Prefectures and future monthly diversion quotas lowered accordingly. More significant breaches of the water diversion quota have resulted in prohibitions on diversions for periods of 14 days. After only 3 years of implementation, quota implementation appears to be proceeding according to agreed quota levels. Since the introduction of the quota 1.7 billion cubic metres have been delivered to Taetima Lake from the KaiduKonque system. This has resulted in a Lake water area of 80-100 square kilometres, groundwater has risen by 57m, plant ecological conditions have been improved over about 800 square kilometres, and the area of rehabilitated Lower Green Corridor is 18,000 ha. In parallel with the reduced quota, the Chinese government has provided major funds ($US 1.3 billion equivalent) to assist with improving ecological conditions along the Tarim River and to improve water management and raising system efficiencies throughout the River Basin. This includes the construction of a 610 km system of levees with flood regulators along the mid Tarim river to assist the transfer of water to the lower river. This section of the river has high flood losses and there is a high Non Beneficial ET and resulting highly saline groundwater discharge sites. An afforestation program is underway along the lower green corridor to reestablish and rehabilitate the natural vegetation. A system of monitoring the vegetation along the river is being implemented including use of remote sensing satellites to monitor vegetation type and condition. BOTTOM-UP INTEGRATED WATER AND ENVIRONMENTAL MANAGEMENT The major reduction in water diversion quota threatens much reduced livelihoods of the dependent communities many of whom already live under difficult economic conditions. A number of studies have shown low irrigation system efficiencies (around 40%) and as a consequence, the Chinese government and World Bank are providing funds to raise the efficiency of water use in the Basin’s irrigation areas. A community based and integrated Land and Water Management Plan, based on experiences from Australia, is being developed on a trial basis in the Fengshou Irrigation Area. Novel aspects of the approach which are being tailored to local conditions include a management Board involving farmers and government officials, a formal planning process with extensive community consultation; identification of a wide range of possible management options (including no-intervention), followed by a sieving and prioritisation process to develop preferred implementation packages. The base package is one that can be largely self-implemented and managed locally. A continual improvement process, whereby the Plan is not a static document but one that is being continually upgraded as new and better information becomes available is also included. As well as the LWMP, an additional
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International Commission on Irrigation and Drainage, 2nd Asian International Conference, Australia. 2004 product will be a community based planning template suited to Chinese conditions which can be rapidly applied to other irrigation areas (probably at a County level) throughout the Tarim Basin. The Plan includes the following aspects: Self Managed Irrigation and Drainage District Self management arrangements for irrigation and drainage are being developed in the study area. This includes a Water Supply Company (WSC) which is responsible for delivering water allocations through the main canal system to 17 Water User Associations (WUAs). Each will be responsible for the management of infrastructure from their respective lateral off-takes, delivery of water allocations to individual household areas and, water fee collection. The plan includes introduction of a specific water allocation for each WUA according to the River Basin Quota conditions; clear and acknowledged responsibilities for the WSC and WUAs; consumption based water pricing following introduction of water measurement and recording facilities down to a household level; capacity building of the WSC, WUA and farmers to assist transition to a water licence and volumetric pricing and fee collection system. Raising Water Use Efficiency A high priority in the plan is to raise water use efficiency. Results of satellite based remote sensing estimates of ET (Waterwatch, 2002) indicate an overall water use efficiency of 40% with consumptive use amounting to 47% of the total ET which implies that the majority of the water resource is used by Beneficial (eg forests) and Non Beneficial (eg wasteland) ET. Water productivity was estimated as 0.24 kg/m3 which is 30% less than global averages. Historically there has been a heavy emphasis on expensive canal lining to reduce water losses. A detailed salt and water balance developed for the project has led to a more targeted approach to canal lining and directed greater emphasis to improving field irrigation practices. Whilst alternative irrigation methods, such as drip irrigation have been considered and are being trialed, laser grading has been introduced and a ‘Whole WUA Planning’ approach taken in order to reconfigure irrigation and drainage layouts to achieve much greater water and management efficiencies. Reducing Winter Irrigation Winter irrigation is widely used to replenish the water held in the soil profile so as to reduce the impacts of the spring ‘drought’ as well as to leach salt. This sets up a viscous cycle of wasteful irrigation causing salinity which requires leaching, which necessitates more wasteful irrigation. It is not feasible to prohibit winter irrigation without great economic cost unless there are water storages to store water from periods when it is in excess of demand. In the meantime, a land use planning approach will be taken to prohibit winter irrigation of highly permeable soils, spring irrigation will be restricted to areas which were not irrigated in winter, and the water allocations during the winter period will be reduced. Salinity Management Salinity has been historically managed by networks of surface drains and heavy leaching especially in winter periods. This has resulted in inefficient use of water, shallow watertables and salinity, and drainage with impacts on downstream water quality. Improved irrigation and drainage practices are expected to reduce salinity conditions, whilst quality and flow based rules are to be introduced to reduce drainage returns to rivers. Equipment (EM38) to rapidly survey soil salinity has been successfully introduced to target soils which should be retired from irrigation due to high salinity. Only 22% of the area had what could be considered as low soil salinity.
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International Commission on Irrigation and Drainage, 2nd Asian International Conference, Australia. 2004 CONCLUSION Impressive progress has been made in introducing an integrated and participative approach to river Basin management in the Tarim Basin. As well as development of the river Basin institution, a diminished water quota has been introduced and measures taken to improve the river and riverine ecosystems. A local participative approach to LWMP including development of water management institutions has been developed on a trial basis and provides a template for more widely introducing LWMP to improve economic, environmental and social conditions. Future evolution of the initiative will involve on-going commitment to the cooperative TBWRC arrangements, further operationalising the current quota and environmental flows system, addressing the environmental water requirements of some of the tributary rivers in the Basin, as well as extending an appropriate participative approach to local Land and Water Management throughout the highest priority Counties in the Basin. ACKNOWLEDGEMENTS The studies which have contributed to this paper have been undertaken by many people and agencies and supported financially by the Xinjiang and Chinese governments with support from the World Bank and AusAID. Acknowledgements are due to all parties. REFERENCES Overseas Projects Corporation of Victoria (1999). Environmental Studies Report. Report to the World Bank. Waterwatch (2003). (www.waterwatch.nl)
Remote Sensing Monitoring in the Awati Pilot Area.
Report to World Bank.
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