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The Sanaga River is one of Sub‐Saharan Africa's largest and greatly regulated rivers. Available flow data for this hydrosystem largely cover the pre‐ and post‐regulation periods. From comparisons between unregulated (hypothetical) and observed scenarios, it has been possible to separate and to quantify hydro‐climatic (groundwater + rainfall) change effects from anthropogenic impacts (especially dam‐related alterations). To appreciate shifts in the river regime, discontinuity detection tests and the IHA model were applied to discharge data series reflecting average and extreme flow conditions, respectively. Results obtained principally from the Hubert segmentation method reveal that a major discontinuity occurred in 1970–1971 separating a surplus phase between 1945–1946 and 1969–1970, and a deficient and much contrasted one, from 1971/1972. This implies that the Sanaga catchment is dominantly affected by hydro‐climatic changes. However, wide land cover/land use changes experienced here since 1988 have resulted in an increase in surface runoff. Additional quickflows linked to these changes may have partly compensated for the substantial decline in the dry season rainfall and groundwater inputs observed from this date. Although at the monthly scale, dam‐related impacts on average flows increase with stage of regulation, the seasonal variability of the river regime remains generally unaffected. A comparison of the IHA statistics, calculated from unregulated and observed streamflow data, show that hydrologic shifts occurring in maximum and minimum discharges are mostly significant from 1971/1972 and are mainly due to the action of dams. Minimum flows appear, however, widely impacted, thus reflecting the prime objective assigned to the existing reservoirs, constructed to supplement flows for hydroelectricity production during the dry season. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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以猴场水电站为例,探讨了小型水电站水轮机导叶关闭规律的优化。在水轮机组的GD2值因制造难度等原因不能加大时,采用导叶关闭的方法,通过优化导叶关闭规律,以满足水电站水力过渡过程计算的要求,从而可以有效地解决机组甩负荷后转速上升和蜗壳进口压力上升的问题。 相似文献
4.
采用一维水动力数学模型和水质数学模型,对梯级电站建设前后的CJ江干、支流的水质变化进行研究,预测CJ江2020年5个梯级电站建设后干流水质主要参数的变化情况。结果表明,各梯级电站水库蓄水后各坝址处平均DO质量浓度将较建库前略有下降,BOD5和NH3-N的质量浓度呈下降趋势,TP质量浓度变化较小。 相似文献
5.
Comparison between dynamic programming and genetic algorithm for hydro unit economic load dispatch 总被引:1,自引:0,他引:1
The hydro unit economic load dispatch (ELD) is of great importance in energy conservation and emission reduction. Dynamic programming (DP) and genetic algorithm (GA) are two representative algorithms for solving ELD problems. The goal of this study was to examine the performance of DP and GA while they were applied to ELD. We established numerical experiments to conduct performance comparisons between DP and GA with two given schemes. The schemes included comparing the CPU time of the algorithms when they had the same solution quality, and comparing the solution quality when they had the same CPU time. The numerical experiments were applied to the Three Gorges Reservoir in China, which is equipped with 26 hydro generation units. We found the relation between the performance of algorithms and the number of units through experiments. Results show that GA is adept at searching for optimal solutions in low-dimensional cases. In some cases, such as with a number of units of less than 10, GA's performance is superior to that of a coarse-grid DP. However, GA loses its superiority in high-dimensional cases. DP is powerful in obtaining stable and high-quality solutions. Its performance can be maintained even while searching over a large solution space. Nevertheless, due to its exhaustive enumerating nature, it costs excess time in low-dimensional cases. 相似文献
6.
Creative hotspots have become a key driver for urban policies to stimulate social, cultural, environmental and organisational growth of creative and knowledge-based clusters, districts and hubs. However, their functional and spatial characteristics vary due to their different evolving structure as new spaces of economic activity in different contexts. This article points to a consideration of new foci for both land use and urban economic policy through a mapping of formal and informal creative hotspots in Brisbane, Australia. The study found two distinctive development patterns: (a) earlier top-down approaches as instigated by national and international innovation policies, and; (b) recently emerging bottom-up spaces for creativity, knowledge and innovation practices. This study examines how formal creative strategies and emerging informal creative spaces shape cities and urban policies. The methodology comprises online data collection and a review of creative and knowledge strategies and implementation policies. Data was then analysed via multiple mapping techniques illustrating the spatial distribution of creative hotspots, formal and informal formations, scale and land use characteristics. The research findings consolidate our understanding of Brisbane’s creative ecosystem and suggest new urban policy mechanisms to better foster the interrelationship between top-down and bottom-up approaches in cities, that is, between formally planned and large-scale interventions and small-scale organic and informal creative activities. 相似文献
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国家能源结构调整加速了水力资源的开发,四川省占有全国水力资源四分之一的经济可开发量.水力资源可持续开发与利用成了四川省发展水电业必须考虑的问题.基于循环经济理论,提出用循环经济原理来指导四川水电开发的思路,并提出了具体的实施方式. 相似文献
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运用系统观点,综合考虑工程及其上游已建成的水利枢纽的共同作用,对施工截流标准的优选进行了研究,提出了多目标风险决策模型,并研究了决策准则和方法。最后给出了计算实例,验证了此法的可行性 相似文献
9.
电力电量平衡算法及其应用研究 总被引:4,自引:0,他引:4
电力电量平衡法原是水电站规划设计中确定装机容量的基本方法,通过对该方法的研究,总结出其应用于水电系统短期调度的突出特点是原理简单、可较好地处理机组连续开停机问题,并可有效地减少优化计算工作量;同时还提出了该原理的数学计算方法及其在水电站群短期优化调度数学模型求解中的应用方法,为计算机软件系统的开发奠定了基础。实际应用表明,该方法合理、实用。 相似文献
10.
以农村水电增效扩容改造试点项目群及浙江省小水电世行贷款项目群为对象,比较研究了项目特性、管理政策、管理模式,以及项目实施流程和项目管理关键环节,在此基础上提出了细化项目约束分析、加强项目关键环节控制等优化我国项目群管理的建议,对优化我国类似项目群管理具有借鉴意义。 相似文献