چارچوب اقتصاد محیط زیست برای ارزیابی جریان های محیط زیست : در مورد انتقال آب بین حوضه ای در لسوتو

This paper used the Lesotho Highlands Water Project (LHWP) that transfers water from the Orange River Basin in Lesotho to the Vaal River Basin in South Africa as a case study to show how environmental sustainability aspects can be integrated into economic development planning. Using the Ecological Social Accounting Matrix (ESAM) for Lesotho that integrates ecological implications of the LHWP with economic benefits of the project, the paper analysed the impact of lost ecological services downstream the LHWP dams in Lesotho on the well-being of households directly affected by the project (riparians) and the general economy of the country. The results revealed that despite significant economic benefits, the project has unintended impacts on ecological resources and services with resultant deleterious well-being implications for riparians. The results from the ESAM analysis indicated that not only the income of riparians is likely to suffer, but also that of other households and social groups, as well as the general economy of Lesotho. While results of the ESAM analysis did not indicate large income impacts on the economy at large, they were significant for riparians. The importance of integrating ecological consequences into impact assessment of IBWT before such transfers can be implemented to ensure sustainable development and considering economy-wide impacts associated with IBWT was proven necessary for a holistic impact assessment of IBWT.

Water is scarce in many regions of the world. But even in countries with an overall abundance of water, demand exceeds supply in many areas. To overcome water deficits, water is often imported through inter-basin water transfers (IBWT) at international, national, regional and local levels to meet increasing off-stream demands in agriculture, industry, hydropower and household for economic and social development. However, offstream gains from IBWT are achieved at high ecological costs downstream. This is because transferring water from one basin to the other can enormously reduce water required for instream uses leading to negative impacts on ecological resources and processes, which provide direct and indirect benefits to riparians. Environmental Impact Assessments (EIAs) for inter-basin transfer projects usually leave out in-stream ecological effects of such projects. The assessments are also often done after important projects' elements have been designed (Hirji, 1998). The Lesotho Highlands Water Project (LHWP) that transfers water from the Orange River in Lesotho to the Vaal River Basin in South Africa is one good example. Recently, the Lesotho Highlands Development Authority (LHDA) commissioned a study to determine Instream Flow Requirements (IFRs) necessary to sustain riverine ecology of rivers downstream the dams of the project in Lesotho (LHDA, 2002a). However, this was done after important elements of the project had been implemented, e.g. part A of the first phase of the project had already been completed and part B had already commenced. It is important that instream impacts of IBWT are measured and included in IBWT impact assessments before such projects are implemented, and that mitigation and compensation measures against possible losses are put in place to ensure sustainable flow of instream benefits to riparians. Otherwise, IBWT may result in unintended negative impacts that threaten the sustainability of such projects in the long run. The major objective of this paper is to develop and apply an ecological economics framework that integrates ecological considerations into economic assessments models to enable more comprehensive evaluation and analysis of the sustainability of IBWT. The LHWP is used as a case study to empirically apply the developed model. The paper is divided into five sections. The next section gives a brief background to the case study area. The analytical framework for assessing economic and ecological impacts of IBWT is discussed in Section 3. Section 4 presents the data and results of the study and conclusions are drawn in Section 5.

Although the magnitudes of the fall in income are small, they are significant for households directly affected by the project. Also, the results clearly show the significance of integrating instream impacts of IBWT in an economy-wide impact assessment. Leaving out instream impacts of IBWT may lead to un-intended deleterious impacts on availability of ecological resources and services direly needed by riparians for survival and hence unsustainable livelihoods in the long term. Because of multiplier effects, instream impacts are not only felt by riparians directly affected by the project, but by the whole economy. Hence, for sustainable development, instream impacts of IBWT have to be measured and compensated or mitigated against to ensure sustainable development.