Assessing Water Quality of Three Gorges Reservoir, China, Over a Five-Year Period From 2006 to 2011

Understanding temporal variability in water quality in the Three Gorges Reservoir (TGR) is crucial for evaluating environmental effects of damming and protecting China’s largest freshwater resource. This study examined water quality changes in the main channel of the Yangtze River after dam completion as well as its relationship with water level fluctuation (WLF), controlled by annual impoundment operations and conditioned by flooding. Finally, the mass balance budget and integrative water quality indexing (WQI) methods were applied to elucidate the status of overall water quality since dam completion. Results showed that TGR outlet water (Yichang) exhibited higher pH and CODMn values and lower concentrations of dissolved oxygen (DO) and ammonia nitrogen (NH3-N) than inlet water (Zhutuo). Temporal variations in water quality parameters displayed similar trends for the outlet and inlet. Water quality parameters all showed negative correlations to water level, revealing the different effects of damming on water quality. It was estimated that reservoir impoundment led to a DO depletion of 1495.5 (±1482.0) × 103 tons/yr and a CODMn increase of 564.0 (±405.0) × 103 tons/yr, likely deriving from various internal pollutant loads from the WLF zone and tributary watersheds. According to WQI, TGR water quality remained at healthy levels. However, WQI linear regression showed that water quality at the outlet significantly decreased over time, indicating that the construction of the Three Gorges Dam generally caused water quality deterioration. Further investigation is required to determine the spatial distribution of point and non-point pollution sources and to identify major factors that influence TGR water quality.

[1]  Ping Xie,et al.  A novel flushing strategy for diatom bloom prevention in the lower-middle Hanjiang River. , 2012, Water research.

[2]  Shaw L. Yu,et al.  Planning for Implementation of Riparian Buffers in the Feitsui Reservoir Watershed , 2010 .

[3]  C. Stow,et al.  Long-term changes in watershed nutrient inputs and riverine exports in the Neuse River, North Carolina. , 2001, Water research.

[4]  Zhilin Huang,et al.  Reductions in non-point source pollution through different management practices for an agricultural watershed in the Three Gorges Reservoir Area. , 2010, Journal of environmental sciences.

[5]  S. McLachlan.  The rate of nutrient release from grass and dung following immersion in lake water , 1971, Hydrobiologia.

[6]  EMILY H. STANLEY,et al.  A Geomorphic Perspective on Nutrient Retention Following Dam Removal , 2002 .

[7]  G. Morris,et al.  Reservoir sedimentation handbook : design and management of dams, reservoirs, and watersheds for sustainable use , 1998 .

[8]  Xihua Cao,et al.  Nutrient characteristics in the Yangtze River Estuary and the adjacent East China Sea before and after impoundment of the Three Gorges Dam. , 2009, The Science of the total environment.

[9]  Nan Zhang,et al.  Influence of Reservoir Operation in the Upper Reaches of the Yangtze River (China) on the Inflow and Outflow Regime of the TGR-based on the Improved SWAT Model , 2012, Water Resources Management.

[10]  Meng Jijun.  Integrated Landscape Ecology Evaluation Based on RS/GIS of Three-Gorge Area , 2005 .

[11]  M. Mustapha.  Assessment of the Water Quality of Oyun Reservoir, Offa, Nigeria, Using Selected Physico-Chemical Parameters , 2008 .

[12]  M. Rahman,et al.  Deterioration of water quality of Surma river , 2007, Environmental monitoring and assessment.

[13]  M Rode,et al.  Long-term behaviour and cross-correlation water quality analysis of the River Elbe, Germany. , 2001, Water research.

[14]  Ze-cheng Wang,et al.  Effects of Submerged Macrophytes on Sediment Suspension and NH4-N Release under Hydrodynamic Conditions , 2010 .

[15]  Jun Xia,et al.  Impact of Water Projects on River Flow Regimes and Water Quality in Huai River Basin , 2010 .

[16]  M. Xenopoulos,et al.  Natural lake level fluctuation and associated concordance with water quality and aquatic communities within small lakes of the Laurentian Great Lakes region , 2008, Hydrobiologia.

[17]  Philippa J. Mason,et al.  Landslide hazard assessment in the Three Gorges area of the Yangtze river using ASTER imagery: Zigui–Badong , 2004 .

[18]  Idris Mushrifah,et al.  Water Quality Changes in Chini Lake, Pahang, West Malaysia , 2007, Environmental monitoring and assessment.

[19]  Seockheon Lee,et al.  Application of Water Quality Indices and Dissolved Oxygen as Indicators for River Water Classification and Urban Impact Assessment , 2007, Environmental monitoring and assessment.

[20]  A. Wüest,et al.  Nutrient retention in the Danube's Iron Gate reservoir , 2006 .

[21]  K. Yürekli,et al.  Effects of Kilickaya Dam on concentration and load values of water quality constituents in Kelkit Stream in Turkey , 2006 .

[22]  Liu Guo-gang.  Status of Water Quality in the Three Gorges after the Water Storage Period , 2007 .

[23]  F. Fang,et al.  Seasonal variation of nitrogen and phosphorus in Xiaojiang River—A tributary of the Three Gorges Reservoir , 2009 .

[24]  Yuan Jin-fang.  Non-Point Pollution from Farmland of the Three Gorges Reservoir Region , 2007 .

[25]  Qinghua Cai,et al.  The influence of topography and land use on water quality of Xiangxi River in Three Gorges Reservoir region , 2009 .

[26]  Saleh A. Wasimi,et al.  Planning for a Large Dam Project: The Case of Traveston Crossing Dam , 2010 .

[27]  J. Garnier,et al.  Modelling nutrient fluxes from sub-arctic basins: Comparison of pristine vs. dammed rivers , 2008 .

[28]  S. T. Meirelles,et al.  Impact of damming the Mogi‐Guaçu River (São Paulo State, Brazil) on reservoir limnological variables , 2008 .

[29]  C. Wen,et al.  CHANGES IN WATER QUALITY IN THE NEWLY IMPOUNDED SUBTROPICAL FEITSUI RESERVOIR, TAIWAN 1 , 1997 .

[30]  Michael A. Stevens,et al.  Reservoir Sedimentation Handbook—Design and Management of Dams, Reservoirs, and Watershed for Sustainable Use , 2000 .

[31]  Fanghua Hao,et al.  Cascade Dam-Induced Hydrological Disturbance and Environmental Impact in the Upper Stream of the Yellow River , 2011 .

[32]  Zhenyao Shen,et al.  Ammonia adsorption and nitritation in sediments derived from the Three Gorges Reservoir, China , 2010 .

[33]  Desiree Tullos,et al.  Assessing the influence of Environmental Impact Assessments on science and policy: an analysis of the Three Gorges Project. , 2009, Journal of environmental management.

[34]  R Core Team,et al.  R: A language and environment for statistical computing. , 2014 .

[35]  F. Muthuri,et al.  Nutrient relationships in shallow water in an African Lake, Lake Naivasha , 1981, Oecologia.

[36]  Bing Li,et al.  Impact of Dam Construction on Water Quality and Water Self-Purification Capacity of the Lancang River, China , 2009 .

[37]  D. Wunderlin,et al.  Reply to comment on "Use of water quality indices to verify the impact of Cordoba city (Argentina) on Suquia River". , 2000, Water research.

[38]  C. Howard-Williams,et al.  Nutrient leaching from the swamp vegetation of Lake Chilwa, a shallow African Lake , 1978 .