Assessing Nutrient, Biomass, and Sediment Transport of Drainage Ditches in the Three Gorges Reservoir Area

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• 作者：Mathieu Nsenga Kumwimba ; Bo Zhu ; Zhixin Dong ; Jialiang Tang ; Tao Wang ; Liwei Xiao and Diana Kavidia Muyembe
• 刊名：CLEAN – SOIL, AIR, WATER
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：45
• 期：1
• 全文大小：1636K
• ISSN：1863-0669

文摘

The contributions of drainage ditches to the accelerated eutrophication of rivers have rarely been assessed, especially for the Three Gorges Reservoir (TGR) drainage ditches. Forty drainage ditches in the TGR from multiple land use types were extensively investigated for 10 parameters of water quality. The results showed that the concentrations of total nitrogen (TN) and total phosphorus (TP) in the TGR drainage ditches were generally far higher than the internationally recognized eutrophication threshold. Based on this study, both ditch water and sediments from residential land and roadside land had the highest concentrations of nutrients. Possible sources of these nutrients include sewage water and septic tank overflow. Forestland had significantly lower concentrations of nutrients. Residential ditches had higher values of electrical conductivity (EC) and total dissolved solid (TDS) values and lower dissolved oxygen (DO) concentrations. Forestland had lower values of EC and TDS values and higher DO concentrations. The results indicate that the nutrients that have accumulated in the sediments have significant impacts on the water quality in adjacent ditches. A long-term plan must be developed to more strictly control the external loading of nutrients from surrounding land. Action plans to promote the growth of wetland plants in drainage ditches are important for increasing agrochemical retention in the TGR drainage ditches. TGR drainage ditches from residential zones must be actively managed by cleaning and sediment removal to control the risk of nutrients being released into the reservoir.