Determination of the status of stakeholder participation in the management of the Lake Malawi basin through application of Integrated Lake Basin Management

Lake Malawi is the southernmost of the Great Rift Valley Lakes of Africa and boasts the world's greatest freshwater fish biodiversity. Along with its basin, the lake provides many benefits to the country of Malawi. Settlements, agriculture and fishing are some of the major uses of the lake basin, making community involvement a necessary component of its management. With the use of key informant interviews, questionnaire survey, document review and site observations, this study demonstrates the applicability of the Integrated Lake Basin Management framework in the Lake Malawi Basin in regard to stakeholder participation. The main objective was to assess the participation of stakeholders, especially local communities, in the management of the lake basin. The framework applied in this study is discussed. The study findings indicate strong to very strong stakeholder participation, with notably high levels of awareness and women's involvement. Enhancing the understanding of the complex nature of lake basin issues, especially those related to the linkages between the water body and the basin, is a topic requiring further attention.     

基于总入流概念的鄱阳湖设计洪水计算

由于受到江河湖槽自然演变和人类活动的影响,鄱阳湖出湖控制站实测资料无法满足一致性和可靠性要求,再加上湖区水情复杂、观测资料匮乏,导致设计洪水计算面临较大困难。基于入库洪水理论,引入了总入流的计算方法,对于湖区各支流控制站和无控区间来水的流量过程,只考虑传播时间的叠加,避免了对各种自然、人为因素影响的定量计算,计算结果真实反映了洪水量级与时程分配过程,满足设计洪水计算规范要求。计算成果可为鄱阳湖区综合规划、水利枢纽设计提供依据。     

洞庭湖区土地覆被对长江水位变化的响应分析

为了研究长江水位的变化对洞庭湖区土地覆被的影响,基于洞庭湖区近26 a土地覆被遥感影像的解译成果,分别构建了东洞庭湖区和西+南洞庭湖区水域、泥滩、草洲、芦苇地、裸地和防护林面积与对应时段城陵矶水位之间的回归方程。分析结果显示：东洞庭湖区水域、泥滩、草洲面积和西+南洞庭湖区水域面积与城陵矶水位之间具有极显著的相关关系,而芦苇地、裸地和防护林等面积与城陵矶水位之间的关系并不显著;城陵矶水位变化对东洞庭湖区土地覆被的影响明显高于对西+南洞庭湖区土地覆被的影响。此外,依据所构建回归方程,预测长江上游大型梯级电站运行将导致洞庭湖区呈现泥滩和草洲挤占水域的态势。     

碟形湖在鄱阳湖湿地生态系统的作用和意义

"碟形湖"是指鄱阳湖湖盆区内枯水季节显露于洲滩之中的季节性子湖泊,具有特殊的地貌特征和水文特性、复杂多变的湿地景观和丰富的生物多样性等特征.在碟形湖及其周边,湿生与水生植物群落有序分布、季节性演替;静水水域有利于底栖动物和鱼类生长育肥;缓慢下降的水位、逐渐伸展的泥滩为越冬候鸟持续提供丰富的食物和歇息环境,全湖80%以上的水鸟在碟形湖区域越冬.高低不一、分布广泛的碟形湖群有效地缓解了干旱、洪水灾害对鄱阳湖湿地生态系统的冲击,对于维护全球生态系统的完整性和生物多样性具有重要作用.最后提出了加强碟形湖保护和管理的对策.     

基于水资源核算的太湖流域水环境退化成本分析

为合理制定流域水价,加强流域水资源统一管理,提高水资源节约利用水平,促进水资源可持续利用,对水环境与经济社会产生的关系进行综合考量;在核算太湖流域2010年水资源的基础上,分别利用基于防护费用的评估方法和基于损害的水环境退化估价方法,计算分析2010年太湖流域水环境退化成本。结果表明:对污染物进行源头治理不仅是出于对环境保护的考虑,更是尽可能地降低水环境退化成本、避免经济损失的最佳选择。水环境退化分析为合理制定水价及水资源统一管理提供了重要参考。     

阳宗海浮游生物群落结构研究

采用生物多样性指数方法,对2013年阳宗海湖泊的浮游生物群落结构进行研究。结果表明,阳宗海湖泊共检出浮游植物7门39属,蓝藻门的拟鱼腥藻和泽丝藻为优势种群;浮游动物鉴定出33种,轮虫为优势种;浮游植物和浮游动物的香浓多样性指数在1.10~2.83之间,均匀度指数在0.37~0.88之间,属于中度污染,阳宗海湖泊已处于中营养状态,并有向富营养化过渡的趋势。     

太湖流域西部地区面源污染特征及其控制技术

针对太湖流域西部地区源污染的主要来源,依据由单元田间试验和小流域出口营养盐输出监测值与流域土地利用结构关系推算获得输出系数,计算了种植业典型土地利用类型的COD、TN、NH3-N和TP的排放量,结合其他种类面源排放量,指出太湖流域西部地区农业面源污染呈现出农村生活污水和种植业污染为主的排放特征。提出了面源污染适宜推广的处理模式,梳理不同种类面源污染处理存在的主要问题并相应提出面源污染控制建议,为太湖流域面源控制提供参考。     

Distribution, relative abundance, and prey demand by double-crested cormorants on Manitoulin Island lakes vs. Lake Huron Coast

An aerial distance sampling survey of double-crested cormorants (Phalacrocorax auritus) was conducted in the northern region of Lake Huron (North Channel; four largest lakes of Manitoulin Island; South Shore of Manitoulin Is. facing the main body of the lake) to assess the relative distribution, abundance and prey demand by cormorants on inland lake vs. coastal habitat. On a per area basis, the density (approx. 1-2 cormorants ? km^− 2) and prey demand (approx. 1.2 kg ha^− 1) of cormorants in the four inland lakes matched that of the North Channel. The South Shore had approximately half the density and prey demand as the other two areas. Cormorants on the inland lakes of Manitoulin Island represented 13% early in the season and a high of 33% of the total population for this region of Lake Huron later in the summer. Estimating regional distributions of cormorants within the Great Lakes basin is important because mapped nest colonies and nest counts are not representative of the actual distribution of foraging cormorants during and after the nesting season. There are two general conclusions to emerge from this survey. First, aquatic productivity from both Great Lakes coast and inland lakes contributes to trends in population and distribution of cormorants in the northern region of Lake Huron and perhaps elsewhere. Second, inland aquatic ecosystems are important throughout a season for foraging cormorants from the Great Lakes and may become more important as Great Lake productivity trends downward.     

Thiamine concentrations in lake whitefish eggs from the upper Great Lakes are related to maternal diet

Thiamine deficiency is responsible for reproductive impairment in several species of salmonines in the Great lakes, and is thought to be caused by the consumption of prey containing thiaminase, a thiamine-degrading enzyme. Because thiaminase levels are extremely high in dreissenid mussels, fish that prey on them may be susceptible to thiamine deficiency. We determined thiamine concentrations in lake whitefish Coregonus clupeaformis eggs from the upper Laurentian Great Lakes to assess the potential for thiamine deficiency and to determine if thiamine concentrations in lake whitefish eggs were related to maternal diet. Mean thiamine concentrations in lake whitefish eggs were highest in Lake Huron, intermediate in Lake Superior, and lowest in Lake Michigan. Some fish had thiamine concentrations below putative thresholds for lethal and sublethal effects in salmonines, suggesting that some larval lake whitefish may currently be at risk of at least sublethal effects of low thiamine concentrations, although thiamine thresholds are unknown for lake whitefish. Egg thiamine concentrations in lake whitefish eggs were statistically significantly related to isotopic carbon signatures, suggesting that egg thiamine levels were related to maternal diet, but low egg thiamine concentrations did not appear to be associated with a diet of dreissenids. Egg thiamine concentrations were not statistically significantly related to multifunction oxidase induction, suggesting that lower egg thiamine concentrations in lake whitefish were not related to contaminant exposure.     

Bed morphology, flow structure, and sediment transport at the outlet of Lake Huron and in the upper St. Clair River

An integrated multibeam echo sounder and acoustic Doppler current profiler field survey was conducted in July 2008 to investigate the morphodynamics of the St. Clair River at the outlet of Lake Huron. The principal morphological features of the upper St. Clair River included flow-transverse bedforms that appear weakly mobile, erosive bedforms in cohesive muds, thin non-cohesive veneers of weakly mobile sediment that cover an underlying cohesive (till or glacio-lacustrine) surface, and vegetation that covers the bed. The flow was characterized by acceleration as the banks constrict from Lake Huron into the St. Clair River, an approximately 1500-m long region of flow separation downstream from the Blue Water Bridge, and secondary flow connected to: i) channel curvature; ii) forcing of the flow by local bed topography, and iii) flow wakes in the lee side of ship wrecks. Nearshore, sand-sized, sediment from Lake Huron was capable of being transported into, and principally along, the banks of the upper St. Clair River by the measured flow. A comparison of bathymetric surveys conducted in 2007 and 2008 identifies that the gravel bed does undergo slow downstream movement, but that this movement does not appear to be generated by the mean flow, and could possibly be caused by ship-propeller-induced turbulence. The study results suggest that the measured mean flow and dredging within the channel have not produced major scour of the upper St. Clair River and that the recent fall in the level of Lake Huron is unlikely to have been caused by these mechanisms.