The ultimate objective was to improve the efficiency of operation and the sustainability of Vietnam’s publicly-managed irrigation systems, and to develop and implement a comprehensive system of performance evaluation.
Vietnam’s food supply is critically dependent on irrigated agriculture. About 80% of the 4 million hectares of cultivated paddy have some form of irrigation, although the area effectively irrigated is probably just over 2 million ha due to incomplete systems, planning and design inefficiencies, and poor operation and management.
With population growth, Vietnam’s food requirements are expected to double by 2030. However, the current standard of operation, management and institutional arrangement for irrigation and drainage in Vietnam is inadequate to meet the challenge of such a large increase in food output.
Earlier ACIAR-funded focused on improving the technical capacity of the main irrigation system, and on establishing the institutional arrangements and legal framework needed to meet the changing socio-economic conditions. Scientists applied the IMSOP (Irrigation Main System Operation) model to the La Khe irrigation system in the Red River Delta. This project transferred and adapted project outcomes to suit the Dan Hoai irrigation scheme (also in the Red River Delta) and to the Cu Chi irrigation scheme in the Saigon River system.
In essence, ACIAR project 9834 is a technology transfer exercise, with a limited research component. The overall objectives of ACIAR 9834 are quite ambitious and rely on a lot of basic work being undertaken by the three irrigation companies, who are partners in the project. To date, progress against project objectives has been slow, despite some adjustments made to the workload of various partners in the course of 2000. Most of the basic data collection required in the project has been done by the end of the year, but progress with modelling and diagnosis and action concerning operational and management improvements has been limited. Various initiatives to promote rapid data collection (such as the use of GPS) have not proved to be as effective as hoped, although the technology is clearly very good.
The operation of La Khe main system appears to have improved year by year since 1998, with improvements in the consistency and height of water levels at the lower end of the canal, and improved distribution uniformity between up and down-stream service areas. This shows that even simple improvements to operational rules can have an impact in systems with relatively poor infrastructure.
The main thrust of the modelling work in 2001 will be to establish the historical performance of water deliveries at Dan Hoai and Cu Chi. This will be followed by further investigation of water delivery requirements at Cu Chi for anticipated cropping when the development of command area is complete. A set of operational rules will be formally drawn up. Following this work there will be some analysis of how water savings (for on-sale to the municipality of Saigon) can be obtained, and what storage requirements are implied. A priority task is to establish routine use of IMSOP at Cu Chi for weekly operation, especially as the level of computer literacy there is already good.
At Dan Hoai, work will focus on the development of a set of operational rules which will include the optimisation of pumping and gravity inflow, water sharing between upper and lower reaches and recommendations for improved hydraulic structures to adequately control water levels in the newly lined main canal. At Dan Hoai there is a significant change to growing non-rice crops in the Spring season, and suitable operational regimes will be investigated to service these high value growers adequately.
Institutional development is by nature a long term process, and work has progressed well at N5 secondary canal in La Khe, but is very much confined to this one location. It is proving difficult to obtain sufficient commitment at appropriate levels of government to scale up this work and see it through. Institutional reform in water management is an unknown arena in the south of the country, but there are strong indications that this work will proceed rapidly in 2001 at Cu Chas a results of company’s progressive management style.
In brief summary, we have seen very good commitment and effort by the staff of Cu Chi irrigation system in the south, but technical support has been less effective due, in part, to the relatively limited experience of the researchers who started this project without grounding from ACIAR 9404. We note that there is, however, a good spirit of co-operation between the irrigation company and SIWRR and UTS. In the north, we have seen a relatively poorer response from the irrigation companies, especially at Dan Hoai. Unfortunately, there has been a high rate of staff turnover in the north especially at VIWRR due to key staff going overseas for post-graduate training, and this has resulted in a loss of technical capacity and experience, particularly with modelling.
At the inception workshop, it was foreseen that data management would be very important, and that timely analysis of data, using considerable local initiative, would be required. The relative lack of data available in this report is an indication that the project should strive to improve this aspect in 2001 and, as far as is possible, operationalise routine work at the irrigation company level and develop sustained commitment to the work-plan agreed at the inception workshop. It is also clear that the institutes will need to provide more assistance and leadership for the irrigation companies to better handle field data collection.
The project has suffered from the untimely death of Mike Bryant, in terms of a loss of economic direction and expert manpower. The project has investigated sourcing local economic expertise, but has concluded that an Australian-based replacement is needed to give clear direction and guidance. The project has been very fortunate to obtain the services of Tim McGrath, to assist in the institutional sphere, not least because of his excellent language skills and continuous presence in Vietnam.
Research on the application of radar remote sensing to map rice by growth stage has proceeded according to schedule, with some minor delays in data acquisition due to a delay in the PACRIM flight programme of three months and subsequent security clearance problems in Vietnam. A comprehensive set of data has been collected on 450 ha in the Philippines, with both radar and optical data available for analysis in 2001. Synthetic aperture radar images (AIRSAR) and optical data (MASTER) were obtained by NASA in September 2000 and requests for detailed imagery at the two groundtruth sites have been submitted. The groundtruth data covered all rice growth stages, with relatively large blocks sampled as well as areas with significant plot to plot variation. The groundtruth data will be co-registered to maps and aerial photographs in early 2001 and preliminary analysis will be conducted when the radar imagery is received. A fully methodology for analysis of the data has been developed. The project aims to have some preliminary supervised classification of rice and estimates of accuracy from training and test locations by the end of 2001.
This project comprises a mix of two sets of activities: (a) Technology Transfer and (b) Research and Development. The technology transfer component is focused on basic aspects of water management at the farm and main delivery system level and an exploratory analysis of prevailing institutional arrangements in Vietnamese irrigation and proposal of alternative arrangements. Project 9834 comprises three subprojects, which are carried out at two project sites: Northern and Southern Vietnam. The activities were designed to accommodate the agriculture features of each region and the resources and capacity of local staff to carry out the field activities. Subproject I focuses on the application of computer modelling to guide the operation of the irrigation system and application of institutional framework. Data collection for the application of the model is continued this year. A Vietnamese version of the software was developed and is installed for use by company staff.
In Cu-Chi the whole system is divided into 19 service areas and monitoring and water balance of each service area can be carried out using the model. The diagnostic analysis in Cu Chi suggests that there is a large volume of over supply in most of the service areas. The quantity oversupplied was estimated as 62 MCM in 2002 and 119.5 MCM in 2001. This indicates that there is ample opportunity for reducing supply to the level demanded by crops and satisfies the increasing demand for water by the HCMC metropolitan area.
Two new operational scenarios were planned and tested in the field to enable the Cu Chi Company to reduce oversupply and improve equity of distribution between service areas. This process has enabled company staff to understand the advantages of using the new operational rules, which can save a large quantity of irrigation water and make the operation simpler. Company staff is now fully capable of planning new scenarios using the IMSOP model. A preliminary analysis of the operation field trial revealed a significant reduction in supply and improved uniformity of distribution among service areas. The modelling analysis has progressed further in Cu Chi to determine the availability of surplus water currently allocated to the system to potential transfer to Ho Chi Minh City. A comprehensive analysis of water reallocation to HCMC and effect on the security of supply in the Cu Chi system was undertaken using three levels of rainfall probability. The IMSOP model was used to estimate the irrigation requirement for all the three seasons. It is concluded that at 90% of probability of occurrence of rainfall the company will be able to supply three times more than the proposed 150,000 m 3 /day assuming a flow availability of 11 m 3 /sec at the head of the system.
The retrospective operational analysis in Dan Hoai suggests a consistent under supply of water in the system. Since most of the offtakes in the system are uncontrolled, it is very difficult to implement any rotational scenario over the entire system. The overall distribution of irrigation water in the system is also very inequitable: in some canals it is over supplied and in some others it is under irrigated. After discussing with the company staff, a single scenario has been selected which will be field-trialled in the upcoming Spring season.
Presently the irrigation companies lack a system to generate the future investment requirements and the overall cost of delivering irrigation water. The project team designed and developed a GIS based software facility for the management of assets in Dan Hoai and Cu Chi. The GIS forms the backbone of the asset management display software interface. It can be used to maintain an up-to-date database of asset condition and carry out various financial calculations including depreciation and condition based renewal costs. The basic capabilities of the model have been tested and used to explore the sensitivity of infrastructure cost to several parameters including prevailing interest and inflation rates and asset life. Further analysis shows that current levels of maintenance of 0.2 to 0.4% of capital cost are highly inadequate to ensure the sustainability of the hydraulic infrastructure.
A seven-step development process leading to the formation of a Water User Association under the Cooperative Law in secondary canal N5 in the La Khe irrigation system was completed and trialled for 2 years. The WUAC model had provided benefits to farmers although it is largely viewed by local authorities as an advisory body. A WUA charter, internal regulations and constitution were developed. Whilst the model was shown to function well as a locally managed irrigation and drainage organization the future extension of this model to other systems is closely linked to the ability of the Vietnamese authorities to speed up reforms in the irrigation sector.
The main effort in Subproject II was directed to the evaluation of water productivity in Cu Chi and economic analysis to evaluate the water management changes. Water balance measurements were carried out in the experimental area for the main crops in 2001 and 2002 and Winter-Spring crop in 2002. The analysis of water balance shows very low water productivity of rice in Cu Chi in both the years. During Winter-Spring season the farmers cultivated peanuts and corn in addition to rice. Corn was found to be substantially more productive than rice and peanut.
The economic component of the study focused on the assessment of farmer’s gross margins, the financial situation of water supply companies and the impact of available water supply on rice yields, returns from agriculture and household income. The impacts of different water availability levels on rice yields and farmer’s income was found to be statistically insignificant. The approach of estimating the demand for water using an evapotranspiration rate, as is used in the IMSOP operation model is the most logical approach for these systems. The data for the analysis of the financial performance of the water supply companies in Dan Hoai and Cu Chi has been collected and the analysis is currently in progress.
During 2002, an extensive analysis of the economic survey of 44 farms in the Cu Chi irrigation scheme was undertaken. The results indicate that water supply for irrigated rice production in Cu Chi will not affect rice yield and the income levels of farmers. The study also revealed that the cost of water paid by farmers is so insignificant that a relative increase in price would provide little or no incentive for farmers to reduce water application to rice fields suggesting that alternative measures need to be explored to curtail excessive water use. The analysis of AirSAR imagery commenced in early 2002 and is still in progress.
The analysis of the ground truth data at Gapan (District 4) UPRIIS was completed but the classification accuracy statistics could not be derived due to some data errors. A set of successful image classifications have been performed using the Mahalanobis distance classifier. However the confusion matrices of the classifications yield very disappointing statistics in comparison to the visual pattern and inspection of the image classification. A process of fine tuning the image classification parameters (class threshold statistics) is carried out and at the moment 18 classes are defined including urban land.
This project focused on the investigation of engineering, agricultural, institutional and economic aspects of improving irrigation management in publicly managed irrigation schemes in Vietnam. It comprised three subprojects which were carried out at three irrigation schemes: two pump-operated schemes located in Ha Tay Province: Dan Hoai and La Khe; and the other, the Cu Chi scheme a gravity-fed scheme located in Southern Vietnam. The project aimed to improve the standard of operation and management of the three irrigation systems by improving their technical capacity to manage water distribution and by introducing new institutional arrangements. It built upon the improvements of the technical capacity of the Le Khe irrigation company and associated new institutional arrangement tested in an earlier project (LWR1/1994/004). The project also developed a system of performance evaluations in terms of resource use, operation, infrastructure use, and finances. Performance evaluation aimed to allow measurement of changes in response to the improved water distribution and institutional arrangements introduced by the project. New areas of research in the project included means of improving infrastructure survey methods and new methods for crop identification and area estimation. The latter were derived from data collected in Australia and the Philippines using airborne synthetic aparture radar.
The project completed the development and application of the Irrigation Main System Operation model (IMSOP) in all three irrigation systems (available in English and Vietnamese). The process involved implementation of the IMSOP model to simulate the operation, retrospective analysis of the system, monitoring existing operation and field trial of alternate operational scenarios.
Project scientists designed and developed a GIS based Asset Management Framework and Software which can be used to manage infrastructure in any irrigation scheme. The software tool can be used to maintain an up-to-date database of asset condition and carry out various financial calculations and modelling including depreciation and condition based renewal costs.
A seven-step development process leading to the formation of a Water User Association under the Cooperative Law in secondary canal N5 in the La Khe irrigation system was completed and trialled for 2 years. The Water Users Association model had provided benefits to farmers although it is still largely viewed by local authorities as an advisory body. A WUA charter, internal regulations and constitution were developed. Whilst the model was shown to function well as a locally managed irrigation and drainage organisation, the future extension of this model to other systems is closely linked to the ability of the Vietnamese authorities to speed up reforms in the irrigation sector.
The main effort in Subproject II was directed to the evaluation of water productivity in Cu Chi and economic analysis to evaluate the water management changes. Water balance measurements were carried out in the experimental area for the main crops in 2001 and 2002 and Winter-Spring crop in 2002. The analysis of water balance showed very low water productivity of rice in Cu Chi in both the years (0.6 kg/m3). During the Winter-Spring season farmers cultivated peanuts and corn in addition to rice. Farmers’ income from rice was estimated at A$400 per ha, whereas combined crop of rice, corn and peanut would give a higher income (A$860 to A$970).
The economic component of the study focused on the assessment of farmers’ profitability, the impact of available water supply on rice yields, returns from agriculture and household income. The study of gross margin in the three systems concluded that a wide diversity exists between systems and within them. Variability in the availability of water within the system appears to have little effect on the yields and incomes of farmers in La Khe. In Dan Hoai there is some evidence that Winter-Spring rice yields are lower for farms located at the end of the irrigation system. In Cu Chi, yields for all rice crops were lower for farms at the end of the system, and net returns per hectare from cropping activities highest at the top of the system. It should be remembered however that many factors other than water availability affect crop yields and this study does not account for other possible factors influencing yield variability.
The process of implementing volumetric prices in Vietnam is difficult, due to institutional immaturity, and the nature of the irrigation infrastructure in Vietnam. The project proposed that water should be charged according to a two-tier formula based on the water user associations buying water on a volumetric basis from the irrigation management company and charging farmers on an area basis. Such an approach will provide incentives for water users associations to buy as little water as possible and for farmers to ensure that the water is distributed as equitably as possible within the WUA.