Influence of influent tributaries on water quality changes in Lake Mogan, Turkey

Lake Mogan, located in the steppes of central Anatolia, is a vital Turkish ecological system, in terms of its water resources, flora and fauna. The lake also is a unique recreational area for Ankara, the capital of Turkey. However, the lake is currently threatened by severe pollution, being under the risk of serious degradation because of (i) uncontrolled urbanization; (ii) point and non‐point source pollution; (iii) inefficient sewerage systems; (iv) sediment transportation and pollution via influent creeks to the lake; (v) uncontrolled soil erosion in its drainage basin; (vi) inappropriate flood control measures; and (vii) severe degradation of the natural wetlands within its drainage basin. This study evaluates the influence of its influent creeks on the water quality of Lake Mogan, mainly because the creeks are believed to be responsible for the major pollutant load reaching the lake, and because the extensive database documenting this situation has not previously been critically evaluated. Accordingly, this study reviews (i) change in the water quality of Lake Mogan between 1993 and 2002; (ii) the water quality classification of the major influent creeks feeding Lake Mogan; and (iii) the influence of the influent creeks on the water quality of the lake between 1993 and 2004.     

骆马湖水环境变化趋势及对策研究

随着经济发展、城市化率的提高，加之滨湖开发，骆马湖的水质呈现一定的恶化趋势，生态系统遭受破坏，水体富营养化发展有越来越严重的趋势。通过对骆马湖营养化程度和污染原因的分析，提出了一些对策措施和解决办法，以期实现湖泊的生态、环境与经济的协调发展。     

东江河流生态评价及其修复方略

本文通过对大型无脊椎底栖动物状况的调查对东江河流水生态状况进行了分析,并在此基础上提出了生态修复方略。从上游到河口选12个点采集底栖动物样本,发现东江流域底栖动物生物多样性在上游和中游保持在较高水平,而到下游则迅速降低到零。对增江湾、西枝江牛轭湖等处的取样进行分析并探讨改善东江生态的方法。针对不同生态应力提出了3种生态修复方略:1.创造多样性的生物栖息地,开发和形成一系列类似增江湾那样的缓流滞流区,把已经隔离的牛轭湖和江边湖泊湿地重新与江水连通;2.调整大坝运用方式,采取大坝泄放的流量逐渐增加和减少的方式,给生物发出流速增大和降低的信号,使其得以准备和躲避;3.稳定岸坡、控制侵蚀、保护和发育河边植被。     

Phosphorus Inputs to Lake Simcoe from 1990 to 2003: Declines in Tributary Loads and Observations on Lake Water Quality

Total phosphorus (TP) inputs to Lake Simcoe have led to hypolimnetic dissolved oxygen (DO) depletion and loss of cold water fish habitat. Since 1990, efforts have been made to reduce the total TP input to the lake below a defined target of 75 t/year, which was predicted to lead to reductions in spring TP concentration and improvements in end-of-summer hypolimnetic DO concentrations. The total TP load to the lake during the most recent period of record (1998/99-2003/04) ranged from 53 to 76 t/yr and averaged 67 t/yr, compared to an average of 114 t/yr estimated between 1990/91 and 1997/98 (range 85-157 t/yr). Reductions in TP loads from the catchment via tributary discharge (∼26 t) accounted for the majority of the decrease in total load between the two time periods. Total P concentrations decreased significantly in four out of six long-term monitored tributaries; however, concentrations in all six tributaries remain above the level recommended to avoid nuisance plant growth (30 μg/L). Although TP loads to the lake are currently below the target 75 t/yr, excessive growths of filamentous algae and macrophytes continue to be a problem in the nearshore zone. End-of-summer minimum hypolimnetic DO concentrations (average 4.3 mg/L, 1998/99-2003/04) remain substantially below the level (7 mg/L) that is considered protective of lake trout. Efforts to reduce TP loads to the lake therefore need to continue.     

Variations in Spectral Slope in Lake Taihu,a Large Subtropical Shallow Lake in China

Spectral slope (S), describing the exponential decrease of the absorption spectrum over a given wavelength range, is an important parameter in the study of of chromophoric dissolved organic matter (CDOM) dynamics, and also an essential input parameter in remote sensing models. Furthermore, S is often used as a proxy for CDOM composition, including the ratio of fulvic to humic acids and molecular weight. The relative broad range in S values reported in the literature can be explained by the different spectral ranges and fitting methods used. A single exponential model is used to fit the S values for 17 investigations involving 458 samples in Lake Taihu from January to October in 2004. The average S value was 15.18 ± 1.39 μm⁻¹ for the range of 280–500 nm, which fell within the range reported in the literature. The frequency distribution of S value basically obeyed a normal distribution. Significant differences in S values between summer and other seasons showed that phytoplankton degradation was one of the important sources of CDOM in summer, whereas CDOM mainly came from the river input in other seasons. Furthermore, the estimated S value decreased with increasing wavelength range used in regression. The maximum and minimum values derived from the regression were 17.89 ± 1.25 μm⁻¹ and 13.62 ± 2.11 μm⁻¹ for the wavelength ranges of 280–380 nm and 400–500 nm, respectively, a decrease of 23.9%. S values significantly decreased with the increase of CDOM absorption coefficients. CDOM absorption coefficients could be more appropriately estimated from exponential model introducing the variation of S with absorption coefficients, making them useful for a remote sensing bio-optical model of Lake Taihu. DOC-specific absorption coefficient a*(λ) and the parameter M describing molecular size of the humic molecules could also be used as a proxy for the sources and types of CDOM. A general relationship was found between S and a*(λ), and M values. S increased with the decrease of DOC-specific absorption coefficient and the increase of M corresponding to the decrease of molecular weight.     

水动力作用下太湖底泥的再悬浮通量

对太湖梅梁湾水体开展了两次野外实验，利用沉积物捕获器收集沉积物，研究了太湖悬浮物的沉降特征，计算了悬浮物的沉降通量和再悬浮通量，并建立了其与风速的关系。结果表明：太湖无机颗粒沉降是悬浮物沉降的主要形式。太湖平均风速在8m/s以内时，总悬浮物、有机物颗粒和无机物颗粒的沉降通量和再悬浮通量均呈现随风速增大而增大的特性，风速大小直接影响悬浮物在垂向的分布及垂向的沉降通量分布，并且相关性较好。该结论说明Gansith公式法适合于计算太湖再悬浮通量。     

An Interval Fuzzy Multiobjective Watershed Management Model for the Lake Qionghai Watershed, China

Integrated watershed management is required to ensure the reasonable use of resources and reconcile interactions among natural and human systems. In the present study, an interval fuzzy multiobjective programming (IFMOP) method was used to solve an integrated watershed management problem. Based on system analysis, an IFMOP model suitable for a lake watershed system {IFMOPLWS} was developed and applied to the Lake Qionghai watershed in China. Scenario analysis and an interactive approach were used in the solution process. In this manner, various system components were incorporated into one framework for holistic consideration and optimization. Integrality and uncertainty, as well as the multiobjective and dynamic characteristics of the watershed system, were well addressed. Using two scenarios, two planning schemes were generated. Agriculture, tourism, macroeconomics, cropland use, water supply, forest coverage, soil erosion, and water pollution were fully interpreted and compared to identify a preferable planning alternative for local agencies. This study showed that the IFMOPLWS is a powerful tool for integrated watershed management planning and can provide a solid base for sustainable watershed management.     

浮选柱处理滇池污水的工艺初探

针对滇池水污染的状况和治理现状，对目前国内采用ICEAS工艺的污水处理厂脱氮除磷效果不佳的现状，此工艺采用浮选柱作为浮选设备，并采用充以臭氧等新的技术，能更有效地解决滇池污水中的氮、磷、有机悬浮物、COD污染物，预计会有很好的研究价值和应用前景。     

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本文采用流动模拟实验方法,以渗透率损害率为评价气层损害的定量标准,对以川东石炭系为主的完井液损害程度及滤失深度进行了试验研究,并对地层损害进行了预测。     

鄱阳湖区冬季水灾考证

根据史料记载和近期水文资料进行考证分析,表明鄱阳湖区历史上曾出现过冬季水灾,既有涝灾也有洪灾.