The Ecological Changes And Its Influence In Manwan Reservoir Area For Twenty Years

Manwan Power Station, built in1993, is the first major hydropower project built on the Lancang River in China. This paper attempts to analyze the major ecological changes of the Manwan reservoir area since the construction of the dam nearly20years ago utilizing the results of previous studies in the region and recent remote sensing and field survey data. This research provides an assessment of the ecological impact of the power station and provides the basis for future assessment of the Manwan Power Station and furthers our ability to assess the ecological impact of the construction and operation of other hydropower stations. The following three aspects are discussed in this paper:1) the main eco-environmental changes of the reservoir area,2) the main driving factors behind these changes and3) the impacts on the local immigration livelihoods. Our conclusions are summarized below.(1) Since the Manwan Power Station was built nearly20years ago, farmland and building sites have increased in1991-2004, while the woodland and other undeveloped land have decreased. These indicate that the ecological condition, immigration livelihood resources and environmental conditions of the reservoir area have not improved.(2) There are several factors that can explain this phenomenon. First, most of the reservoir human resettlement is placed in situ, which leads to an increasement of population density surrounding the reservoir area and increases pressure on the arable land. Second, due to a serious arable land pressure, more and more sloping land reclamation and forest land reduction, there is further deterioration of the ecological environment.(3) Changes in the ecological environment and immigration livelihoods are largely driven by policy factors. Inadequate compensation and the decline in the quality of the reservoir area of cultivated land, has led to the decline in reservoir resettlement food production and income, so that the standard of living of many of the reservoir resettlement population has become lower while the standard of living of a few more prosperous farmers has increased significantly, resulting in a very large disparity in standard of living.(4) In recent years, as immigration policy shifted to the "blood" by the "blood type", there also was more financial support from the Government and continued guidance and encouragement for immigrants to adjust agricultural structure to change the original monoculture practices. With this change, grain production achieved good results and the reservoir resettlement, production and living standards after a few years improved.(5) This case study found that with recent immigration support efforts, immigrant support in the later stage of the capital increased by200yuan per year, with the major source of income of reservoir resettlement being agricultural income, while other sources of income were less and availability of capital became more difficult than before.