Water Supply Source Options
Attributes
Medium: Water
Country: Vietnam
Analytical Framework(s): Other
Study Date: 2007
Publication Date: 2008
Major Result(s)
Functional Transfer: Linear Probability Model - This was used to forecast the demand or supply in the ground water market. The results of the model allow one to make a prediction about the probability of a non-GSU household switching to GSU water and the probability of a higher amount of GSU water being sold during the dry season compared with the volume sold during the rainy season as determined by specific characteristics of nonGSU households and GSU managers, respectively. The model is stated as follows: Yi = a0 + a1X1i + a2X2i + … + akXki + … + anXni + ui,
where Yi: dependent variable (dichotomous variable: 1 for willingness to switch to GSU water; 0 for otherwise)
Xki: explanatory variables representing the socio-economic characteristics of the kth non-GSU household or GSU manager and the technical nature of the ith GSU plant
ai: estimated coefficients
ui: error term
Study Note: This study was developed to identify clean water use options, explore the advantages and disadvantages of each option, and analyze household switching behavior across water sources. A survey of non-GSU users (i.e., households that own private tube-wells) and GSU users (i.e., households that buy water from GSUs) was undertaken. An analysis of switching behavior from non-GSU use to GSU use was made. For current GSU users, factors that affected the choice of GSU water in terms of water quantity and quality were identified. Moreover, the reasons for the preferences in water sources were explored for both GSU and non-GSU users. Finally, the factors affecting the operation and management of GSU plants were also studied.
Study Details
Summary: This report identifies the options available to households in the Mekong Delta of Vietnam (VMD) in dealing with the quality of their water sources and presents an analysis of their switching behavior across such sources. The VMD is home to 18 million people who account for 21 per cent of the country's population. There is a huge demand for clean water by its residents. In the rural area especially, although there is a network of rivers, the use of clean water is limited due to pollution from agricultural production activities, aquaculture, and salination in the dry season. A fraction of clean water comes from ground water. Currently, ground water is mostly extracted from shallow tube-wells at the household level and ground water plants that are installed by the government via a rural development program. The objective of the rural clean water supply program in the MRD is to provide rural people with access to clean water for domestic use. The fact that the river water is highly polluted and of inferior quality in the dry season and rainwater is hard to collect and store makes ground water the best source of clean water. Clean water supply in the MRD is complex. This study identified six possible management alternatives to deal with the problem of clean water supply using three main water sources: rainwater, surface water, and ground water in the MRD. Clean water alternatives depended on the availability of water resources and the economic condition of the households as well as the type of pollution affecting the water resources. This study found that the water consumption of ground water supply unit (GSU) users was significantly lower compared with those using private tube-wells for their water needs. Even at the highest consumption level, the mean GSU water consumption was only at 109 liter /person/day, which was less than half that of private tube-well users. This result supports the conclusion that switching from private tube-wells to GSU water would encourage water saving, thus preventing ground water resources from being over-extracted. For non-GSU users, the probability of switching to GSU water was found to be 37 per cent. Income played an important role in encouraging households to switch to using GSU water. In addition, the interaction effects between income and the education level of the head of the household and the length of the time the household had settled in the community increased the probability of switching to GSU water.
Site Characteristics: This study was conducted in Can Tho City and Hau Giang Province (formerly part of Can Tho Province). The study site was located in the centre of the VMD covering a total land area of 2,986 km2. The area has two seasons a year: dry and rainy. The dry season is from December to April while the rainy season is from May to November with an average rainfall of about 92-97% of the year's total (1,635 mm per year). The average temperature is 27°C. Can Tho City has abundant surface water and ground water reserves. A network of rivers and canals is interlaced with a total length of 4,300 km and a density of 1.8 km/km2 . The rivers are a rich source of water in the rainy season. However, in the dry season, most rivers and canals are salinized and polluted by agro-chemicals. Consequently, surface water cannot be used for domestic purposes in the remote areas. Can Tho's total ground water reserve is about 5.5 million m3 with a potential extractable quantity of 763,531 m3/day, 384,562 m3/day, and 1,450,407 m3/day for the Pleistoxen, Plioxen, and Mioxen layers, respectively. So far, the ground water is extracted mostly from the Pleistoxen layer. In the year 2000, the total extracted amount of ground water for domestic use was about 57,000 m3/day.
Comments: The analysis of household behavior of private tube-well and GSU water users, as done in this study, helped to identify the demand and supply situation of ground water. Meanwhile, the proper management of ground water is certainly necessary to prevent the possibility of deterioration of this valuable natural resource. Water pricing is the usual recommended solution to this problem. How ground water should be priced, however, is a question that should be answered in a future study on this topic.