Tài liệu Sustainable water management for rural development in the Mekong river delta, Vietnam pptx

The second International Symposium on Southeast Asian Water Environment Hanoi, Vietnam, 1-3 December, 2004 1 SUSTAINABLE WATER MANAGEMENT FOR RURAL DEVELOPMENT IN THE MEKONG RIVER DELTA, VIETNAM L.A. TUAN 1* , G.C.L. WYSEURE 2 , L.H. VIET 1 1 College of Technology, CanTho University, Campus II, Street 3/2, CanTho City, Vietnam. * E-mail: latuan@ctu.edu.vn 2 Laboratory for Land and Water Management, K.U Leuven, Kasteelpark Arenberg 21, B-3001 Heverlee, Belgium Abstract: The Mekong River Delta (MD) in Vietnam has an area of 4 million hectares. The economical production in this region is highly dependent on water from the river and canal system. More than two-third of 17 million inhabitants of the MD live in rural areas and depend totally on the water resources for rice, upland crop irrigation, aquaculture of fish and shrimp, domestic drinking and industrial water supply and for transportation on rivers and canals. In the MD agricultural production consumes around 85% of the total water supply. Approximately 2 million tons of rice, produced in the MD, are yearly exported from Vietnam to the rest of the world. The rapid expansion of intensified agricultural cultivation and urbanization leads to water resources pollution. Shortage of good quality water becomes increasingly a great challenge to the sustainable water management. How to control the quantity and quality of the water efficiently is an important key factor for rural development. This paper will present some data figures and discussion concerning the current problems and strategies to alleviate the bottlenecks in water management. Keywords: sustainable water management, rural development, water quantity and quality. 1. INTRODUCTION The Mekong river (see figure 1) with the length of 4,200 kilometers is the 12 th longest river in the world, its source originates at an altitude of 5,181 meters on the Tibetan Plateau. The river flows down through Southwest China, passes a part of Myanmar, runs a long the boarder between Thailand and Laos, then goes throughout Cambodia and finally reaches out into the East Sea in Vietnam. From year to year, the Mekong River Delta (MD) of Vietnam have been deposited alluvium by the over bank flooding that this land becomes a typical river delta as a great potential region for agricultural production for the whole country. The Delta accounts only 5% of the total the water basin of the Mekong river, about 4 million hectares, but it supplies for more than 50% of staple food, 60% of fish and shrimp and 70% of tropical fruits. It has contributed approximately 2 million tons of exported rice yearly to the world. The second International Symposium on Southeast Asian Water Environment Hanoi, Vietnam, 1-3 December, 2004 2 There are three water quality problems and two water quantity problems that are the principal limit factors of agricultural production in the Delta (i) The salinity intrusion: There are more or less 2.1 million hectares of the MD coastal areas (50%) affected by salinity during the dry season from December to May. (ii) The acid sulfate soils (ASS): Large areas of Long Xuyen Quadrangle and Plain of Reeds and other scattered lands, cover 1.6 millions hectares (40%) of the MD are holding the soil with high iron sulfide content. (iii) The polluted water: The Mekong river is facing more and more water pollution by agricultural and industrial chemicals and domestic untreated wastewater. In some places, this situation is threatening seriously the public health and socio-economic development. (iv) The shortage of fresh water: In the dry season, the average discharge of the Mekong river is lower then 2,500 m 3 /s down to 1,700 m 3 /s. In addition the groundwater table lowers by 2 to 3 m. This water amount is not enough to irrigate nearly 1,5 million hectares of cultivable lands in the dry season. The shortage of freshwater leads to increasing salinity intrusion throughout the MD coastal provinces. (v) The floods: Discharge of the Mekong river during the wet season averages of 39,000 m 3 /sec. About 1,2 - 1,9 million of hectares of the southwestern part of the Delta can be flooded where farming becomes impossible. Although seawater intrusion and floods are considered as limiting factors for agricultural cultivation, they also have positive impacts: Many coastal farmers need saltwater to raise shrimp; and flood flows are to bring alluviums for the fields, to flush polluted water, crop insects to the sea and to supply fishes for the people. All the socio-economic activities in the MD highly depend on the water resources for living and production A typical characteristic of a very flat delta as the MD is the small difference natural level between the sea level in river estuaries and the inner lands. Also the MD is Figure 1: The Mekong River and the MD map The second International Symposium on Southeast Asian Water Environment Hanoi, Vietnam, 1-3 December, 2004 3 affected simultaneously by 2 different types of complicated tides from the East Sea (irregular semidiurnal tide) and the West Sea (irregular diurnal tide) with a great difference amplitude. These create technical difficulties to drain the excess and polluted water to the East Sea. 2. RURAL DVELOPMENT IN THE MEKONG DELTA The MD is affirmed as a biggest agricultural region of Vietnam. It contributes for more than half of Vietnam's total agricultural output, and 27% of Gross Domestic Product (GDP). The MD has 17 million inhabitants (22% of country total), more than two-third among them, farmers and agricultural related workers, are living in the rural and coastal areas where the natural conditions such as lands, water and plants closed density exist. The rest of the MD's population concentrated in the cities, peri-urban areas, mainly along the major roads and waterways. Along the Tien river and Hau river in Vietnam of the Mekong river system every 60 kilometers we have a major city or town. The human settlement points fit a compromise between East Sea tidal effects and the Mekong river flow. The population pressure and the economic development needs have also driven the farmers to increase their income by increasing and diversifying their agricultural and fishery production. Since the past 20 years, the area of cultivable lands have been growing by an expansion the irrigation and drainage canals density system in the Delta. However, parallel with the fast increasing agricultural yields and production, the region is facing more and more water pollution problems by human and animals waste, agro-chemicals as pesticides, herbicides, fertilizers. Flood disasters in the MD led to the loss of more than 1,000 human life and about 1 billion USD damages by in the past decade. For rural and agricultural development in coming years, water needs for the whole MD will mainly include:  irrigation water in dry season for 1,8 million hectares of rice fields as roughly 1.1 to 1.2 liter per second per hectare (l/s.ha) and for nearly 200.000 hectares of perennial fruit trees and industrial crops. Water use in the Mekong delta in 1995 was estimated as 210 million m 3 as compared to 534 million m 3 used by the whole Vietnam (Su, 1996).  domestic water supply for 11 million people in rural areas with the water rate 60 litres per person per day. The need for the rural population is established as approximately 1 million cubic meter per day. 3. DISCUSSION ON SUSTAINABLE WATER MANAGEMENT Sustainable water management (SWM) should not only control the water resources towards the present needs but also consider water-related problems in the future. Processes of the urbanization and industrialization parallel to the rapid population growth lead to a greater water demand for upholding and developing the regional economic. This issue in the MD is also unique for whole Vietnam and the water needs of people may be linked the effort of poverty reduction and living conditions improvement as well. There are three issues to be noticed for SWM in the MD:  Water quantity and quality control  Water distribution and use  Water-related health and environmental needs The second International Symposium on Southeast Asian Water Environment Hanoi, Vietnam, 1-3 December, 2004 4 3.1 Water quantity and quality control Water resources in the MD should be monitored and controlled both in their quantity (discharge, water level, …) and quality (pH, TSS, turbidity, BOD, COD, DO, total nitrogen, total phosphorus, total coliform number, …) according the economical and environmental development requirements. The changes in space and time their characteristics need to be recorded for making a necessary balance analysis. The water quality monitoring routines may be suggested as figure 2: Figure 2: Suggested water quality monitoring routines 3.2 Water distribution and use Water in the MD flows though natural and artificial streams by gravity and open channel flow. In principal, we could try to distribute water according to the human demands by solving the water balance problems and by building a water resources distribution system, which includes pumping stations, sluices, canals, pipelines networks… (see figure 3). As every place has in their close vicinity open water a water distribution solvency is not an economic option. In some cases, shift into less water demanding crop cultivation or a resettlement of the rural living and production into less water consumption is imposed. 3.3 Water-related health and environmental needs In the rural areas of the MD, farmers access water directly from rivers, canals, ponds or shadow wells (Tuan, 2003). By lack of adequate water sanitation facilities the increase and prevalence of Anopheles and Dengue mosquitoes together with other disease vectors is observed. The seasonal transition periods are mostly affected. Some going- on industrial projects have caused pollution of freshwater, intrusion of salinity, water logging of agricultural land, destruction of wetlands and loss of biodiversity in mangrove forest and coastal areas. These negative impacts are slow the rural development in the MD down in the present and future. It is necessary to assess the economic development benefits with the health and environmental impacts in early planning stages. Each result should be presented fully for the entire Water Monitoring Network Water Sampling Collection n Laboratory Analysis and Data Handling Water Quality Modelling Result Information Decision- Making The second International Symposium on Southeast Asian Water Environment Hanoi, Vietnam, 1-3 December, 2004 5 population by the public media. Consideration and feedback is required in order to establish a balance of good quality water with sufficient quantity (figure 4). Figure 3: Establishing water resources systems in the MD Figure 4: Relationship concerned health and environmental needs WATER RESOURCES  Flow forms: + Rainfall + Surface water + Groundwater  Water characteristics: + Quantity + Quality + Dynamics WATER DEMANDS  Irrigation  Domestic uses  Fisheries  ASS reclamation  Salinity prevention  Pollution control  Land washing  etc. WATER BALANCE WATER RESOURCES SYSTEMS WATER DECISION-MAKING Satisfy ? No Adjust demands Yes Monitoring National and Regional Policies Economic Development O bjectives Water Budget Monitoring Network Water Demand and Supply Analysis Community Public Information and Feedback Water Alternatives Solutions and Environmental Impact Assessments Cost-Benefit Analysis and Nonprofit Consideration Decision Makers Decision Reports Implementatio n Health and Environmental Monitoring The second International Symposium on Southeast Asian Water Environment Hanoi, Vietnam, 1-3 December, 2004 6 4. CONCLUSION Some past rural development projects concerning water management in the Mekong River Delta are evaluated as non-sustainable. Some projects only considered the single objectives advantages and did no study human health, environmental impacts, water quantity-quality relations. The decision-making process was top-down with little or no public involvement of the different stakeholders. Water in the MD is important factor in all future planning activities. Although the quantity of water inthe delta is large, the sufficient good quality could become a bottleneck as pollution increases along with a higher demand. So a sustainable water management should be interpreted with the targets of the rural development as meaning water resources system has used to be efficient. 5. ACKNOWLEDGEMENTS Authors would like to say sincerely thanks the Belgium - CanTho University VLIR-E2 project and project staff members for their support. REFERENCES P. J. Haest (2003). The Influence of Long Xuyen City on the Water Quality of the Hau river (Mekong Delta). Master Thesis. K.U.Leuven, Belgium. K.A. Keola (1997). Water Quality Monitoring Network in the Lower Mekong Basin. MRC Workshop "Urbanization and Safeguarding Water Resources in Mekong Riparian Countries", CanTho University, Vietnam. Ministry of Agriculture and Rural Development (2003). Atlas of Some Selected Hydraulic Works of Vietnam. Hanoi, Vietnam. L. Q. Minh (2002). Transboundary Cause-effects of Upstream Development to Environment and Livelihoods in the Mekong Delta, Vietnam. Mekong Dialogue Workshop “International transfer of river basin development experience: Australia and the Mekong Region”, Australia. P. X. Su (1996). Country Paper of Vietnam. In (W. L. Arriens, J. Bird, J. Berkoff, et al., eds.) Towards Effective Water Policy in Asian and Pacific Region: Volume 2 - Country Papers. Proceedings of the Regional Consultation Workshop – Towards a Policy for Water Resources Development in the Asian and Pacific Region. Manila, Philippines, 10-14 May 1996. ADB Manila. L. M. Triet, D. H. L. Chi, N. P. Dan (1997). Environmental Quality Monitoring Results of some Mekong Delta Provinces In the Two Years 995 - 1996. Proceedings of the workshop on "Urbanization and Safeguarding Water Resources in Mekong Riparian Countries". CanTho University, Vietnam. L. A. Tuan (2002). An Overview of the Drinking Water Supply Situation in the Mekong River Delta. Proceedings of the SANSED Project Workshop. CanTho University, Vietnam . in the past decade. For rural and agricultural development in coming years, water needs for the whole MD will mainly include:  irrigation water in. and the Mekong river flow. The population pressure and the economic development needs have also driven the farmers to increase their income by increasing