Valuation Study

Economic Analysis of Salinity Problems

Attributes

Medium: Land

Country: Sri Lanka

Analytical Framework(s): Economic Analysis

Study Date: 1998

Publication Date: 1998

Major Result(s)

Study Note: This study aimed to identify the nature of the soil salinity problem, to investigate its impact on rice production and on environment, and to assess the feasibility of reducing soil salinity for better water management and environmental protection in the Mahaweli system H Irrigation Project in Sri Lanka. Specifically, it aimed to assess the soil salinity and its distribution in the two study areas, measure the salinity impacts on rice productivity, resource use, and profitability under different soil salinity levels, identify the socio-economic and physical factors that influence the salinity control efforts taken by individual farmers, compare the cost of control such as the improvement in drainage and water management; and the benefits of salinity control measures in terms of production loss avoided, and assess farmers' perception on the effect of salinization on the quality of drinking water, health and vegetation in the two study areas.

Study Details

Reference: Selliah Thiruchelvam and S. Pathmarajah. 1998. An Economic Analysis of Salinity Problems in the Mahaweli River System H Irrigation Scheme in Sri Lanka. EEPSEA Research Report, No. 1998-RR.

Summary: Salinity problems are primarily associated with coastal areas and irrigated lands in the dry zone of Sri Lanka, where the total irrigated area is about 0.5 million hectares. Since irrigation has been practiced in these areas from ancient times, salinity might have been a problem at least in patches of irrigated lands. With the development of modern irrigation networks, it is anticipated that salinity would become a problem over the years as in many other countries. Only a few systematic studies exist on the soil salinization problem in Sri Lanka, and there are no records of the actual extent of lands affected by salinity, or data that indicate its trend. Most of the available information comes from sporadic surveys. Recently, however, concerns were expressed that most of the large-scale projects would face salinity problems. Due to the inadequacy of related studies, the actual extent of the problem, both in economic and environmental terms, is unknown in Sri Lanka. This study focused primarily on the problem of soil salinity in the Mahaweli irrigation scheme. The Mahaweli project is one of the largest irrigation projects in South East Asia. This study attempted to measure the impact of soil salinization on rice production and on the environment. It also assessed the optimal control of salinity at the farm and project level for better water management and environmental protection.

Site Characteristics: Land degradation due to salinity and waterlogging is primarily associated with coastal areas and irrigated lands in the dry zone of Sri Lanka, which covers half a million hectares. The dry zone of Sri Lanka is the most important area as far as irrigation is considered. In Sri Lanka the dry zone occupies nearly two thirds of the land where people depend mainly on arable farming for food and income.In Sri Lanka, although irrigation projects have contributed substantially in improving agricultural production, most of the large-scale projects today face salinity problems. The literature available on the salinity effect on production and environment and its trends in Sri Lanka is scarce; papers which examine the environmental impacts are even fewer. Relevant international researches have addressed the salinity problem, in isolation to production and environment.

Comments: Previous studies on salinity did not venture to establish any relationship between soil salinity and lower rice productivity. These also did not provide any clear indications of the threats posed by soil salinity to the sustainability of natural resources and agricultural growth in years to come. In view of these observations, this study investigated how salinity affects rice production and the environment. Mahaweli H area contributes 25%, 30% and 20% of the national production of paddy rice, chilli, and big onion, respectively. Nearly 28,000 families are dependent on agriculture in the 53,221 ha of old and 37,247 ha of newly developed irrigated areas. The growing salinity problem is likely to have a significant impact on the production and income of the people in these areas. However, the impact of salinity on production and environment has not been fully examined. A number of schemes in the developing countries failed to recover even their operating and maintenance costs, much more the capital costs. Cost recovery was around 7% of the total cost of supply (Sharma & RaO 1997). The growing salinity problem may lead to further management problems of the irrigation scheme and loss of production unless appropriate measures are taken at an early stage. Given the highly dynamic nature of the problem, it is imperative to thoroughly investigate salinization and to formulate strategies to counteract it as well as to reclaim and manage salt-affected areas. The study examined the possible causes of soil salinity in the H area to formulate possible early remedies to the problem in a big project like Mahaweli.

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