RESEARCH ARTICLE Eutrophication in the Yunnan Plateau lakes: the influence of lake morphology, watershed land use, and socioeconomic factors Wenzhi Liu & Siyue Li & Hongmei Bu & Quanfa Zhang & Guihua Liu Received: 2 May 2011 /Accepted: 11 September 2011 /Published online: 27 September 2011 # Springer-Verlag 2011 Abstract Introduction Lakes play an important role in socioeconom- ic development and ecological balance in China, but their water quality has deteriorated considerably in recent decades. In this study, we investigated the spatial–temporal variations of eutrophication parameters (secchi depth, total nitrogen, total phosphorus, chemical oxygen demand, chlorophyll-a, trophic level index, and trophic state index) and their relationships with lake morphology, watershed land use, and socioeconomic factors in the Yunnan Plateau lakes. Discussion Results indicated that about 77.8% of lakes were eutrophic according to trophic state index. The plateau lakes showed spatial variations in water quality and could be classified into high-nutrient and low-nutrient groups. However, because watersheds were dominated by vegeta- tion, all eutrophication parameters except chlorophyll-a showed no significant differences between the wet and dry seasons. Lake depth, water residence time, volume, and percentage of built-up land were significantly related to several eutrophication parameters. Agricultural land use and social–economic factors had no significant correlation with all eutrophication parameters. Stepwise regression analyses demonstrated that lake depth and water residence time accounted for 73.8% to 87.6% of the spatial variation of single water quality variables, respectively. Redundancy analyses indicated that lake morphology, watershed land use, and socioeconomic factors together explained 74.3% of the spatial variation in overall water quality. The results imply that water quality degradation in the plateau lakes may be mainly due to the domestic and industrial waste- waters. This study will improve our understanding of the determinants of lake water quality and help to design efficient strategies for controlling eutrophication in the plateau region. Keywords Cropland . Land use . Trophic state index . Water depth . Water quality 1 Introduction Deteriorating water quality is of major concern at a time when freshwater supply is facing rapidly increasing demand in many developing countries, especially in China (Jin 2003; James et al. 2009). Eutrophication, characterized by high nitrogen and phosphorus concen- trations in water body and excessive growth of phyto- plankton and other aquatic plant, is a common consequence of water quality degradation in lakes, ponds, and other aquatic ecosystems (Wang and Dou 1998; Abell et al. 2011). Although eutrophication is generally recog- nized as a natural process in the aging of lakes, human activities (e.g., urban runoff, over-application of inorganic fertilizers, and sewage discharges) can greatly accelerate the process by increasing the rate at which nutrients enter Responsible editor: Zhihong Xu Electronic supplementary material The online version of this article (doi:10.1007/s11356-011-0616-z) contains supplementary material, which is available to authorized users. W. Liu (*) : S. Li : Q. Zhang : G. Liu (*) Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, People’ s Republic China e-mail: liuwz@wbgcas.cn e-mail: liugh@wbgcas.cn H. Bu Chinese Research Academy of Environmental Sciences, Beijing 100012, People’ s Republic China Environ Sci Pollut Res (2012) 19:858–870 DOI 10.1007/s11356-011-0616-z