Trends in low flows of German rivers since 1950: Comparability of different low‐flow indicators and their spatial patterns

Climate change, land‐use shifts, reservoir storage, and water withdrawals impact low flows in rivers, creating challenges for ecological integrity and human uses. A systematic investigation of river discharges was carried out for 79 stream gauges in Germany. Available time series between 1950 and 2013 were analysed for trends in annual minimum low flows, discharge deficits, and low‐flow durations. The application of different low‐flow indicators led to similar spatial patterns, although each metric is used for different purposes in water management applications. Statistical tests identified significant discharge trends at more than half of the stations investigated. Low‐flow trends since 1950 tended to be catchment specific, suggesting that climate change has not been the dominant driver. Most of the gauges investigated showed statistically significant increases in low flows. This can be mainly attributed to reservoir management. For rivers showing snow‐ and icemelt‐dominated flow regimes, such trends are probably overlain by climate‐driven changes (increasing amounts of rainfall, earlier snowmelt in spring). In contrast, stations showing statistically significant decreases in low flows were correlated with areas of decreasing mining activity. Hydrologic impacts of climate change are widespread and significant, but the results here suggest that human river management remains the dominant hydrologic driver on many rivers.     

高崖水库现代化水库运行管理矩阵建设探析

阐述了高崖水库现有标准化系统面临的问题,从建设目标、建设任务、建设成效等几个层面介绍了水库现代化运行管理矩阵建设情况。通过现代化水库运行管理矩阵建设形成了可推广、可复制的数字化应用成果和经验,以点带面、统筹推进,为类似水库现代化运行管理矩阵建设提供经验、样板,并引领和带动全国现代化水库运行管理矩阵建设。     

Multi‐scale modelling of land‐use change and river training effects on floods in the Rhine basin

Land‐use changes effects on floods are investigated by a multi‐scale modelling study, where runoff generation in catchments of different sizes, different land uses and morphological characteristics are simulated in a nested manner. The macro‐scale covers the Rhine basin (excluding the alpine part), the upper meso‐scale covers various tributaries of the Rhine and three lower meso‐scale study areas (100–500 km²) represent different characteristic land‐use patterns. The main innovation is the combination of models at different scales and at different levels of process representation in order to account for the complexity of land‐use change impacts for a large river basin. The results showed that the influence of land‐use on storm runoff generation is stronger for convective storm events with high precipitation intensities than for long advective storms with low intensities. The simulated flood increase at the lower meso‐scale for a scenario of rather strong urbanization is in the order of 0 and 4% for advective rainfall events, and 10–30% for convective rain storms with a return period of 2–10 years. Convective storm events, however, are of hardly any relevance for the formation of floods in the large river basins of Central Europe, because the extent of convective rainstorms is restricted to local occurrence. Due to the dominance of advective precipitation for macro‐scale flooding, limited water retention capacity of antecedent wet soils and superposition of flood waves from different tributaries, the land‐use change effects at the macro‐scale are even smaller, for example at Cologne (catchment area 100 000 km²), land‐use change effects may result in not more than 1–5 cm water level of the Rhine. Water retention measures in polders along the Upper and Lower Rhine yield flood peak attenuation along the Rhine all the way down to the Dutch border between 1 and 15 cm. Copyright © 2007 John Wiley & Sons, Ltd.     

Reservoir system management and environmental flows

Considerable attention has been paid to the downstream effects of reservoirs on the ecology of rivers, streams and wetlands. However, most reservoirs were constructed well before ecological concerns became prominent. Little attention has been given to the question of what extent existing structures and management systems can accommodate changes. The paper discusses this matter and a range of associated issues. It is concluded that many problems can be rectified by structural means but that such rectification will be very expensive. While based primarily on Australian systems, the conclusions and examination are considered to be globally applicable.     

The impacts of power boating and water skiing on lakes and reservoirs

Over the last 30 years, the use of motorised recreational craft on inland waters has increased significantly, and it is likely that this trend will continue. This growing use of rivers, lakes and water storage reservoirs for recreational purposes has led to concerns about increasing anthropological pressures on freshwater environments. As a result, numerous studies focusing on the possible impact of power boats on inland waterbodies have been undertaken since the early 1970s, when attention started to be drawn to environmental impacts associated with this type of recreation. This paper presents an overview of identified and documented physical, chemical and biological impacts as a result of motorised recreational activities on lakes and reservoirs. Relevant literature, including research papers, government reports and bibliographies, was consulted in the preparation of this review. It has become obvious that in the past, biological impacts have been underestimated. Thus, there is a need for further, more focused, research into the impacts on not only freshwater ecosystems but on terrestrial biota surrounding recreational waters.     

One hundred years of applied storage reservoir theory

The paper summarizes what the author considers to be the most important and most interesting aspects of the development of the applied deterministic as well as stochastic theory of reservoir storage during the past century.     

清江梯级水库HEC-ResSim模型调度规则研究

采用美国陆军工程兵团的水库调度软件模型HEC-ResSim对清江梯级水库进行了模拟调度演算和效益评估.模型分别选用1955～2005年丰、平、枯典型年3小时历史实测径流资料,通过与常规调度方法的结果相比较,提出了适宜于该流域梯级特性的调度规则.模拟研究的结果表明,HEC-ResSim模型对于丰水年、平水年以及所有年份的蓄水期调度效果优于常规的方法,而在枯水年及所有年份的供水期的调度效果改进不明显.     

神府,东胜煤田矿点井田区综合治理模式探讨

随着矿区建设，煤矿生产与区域瓣相互影响日益突出。根据神府，东胜煤田煤矿开发方式和分布位置的不同，将矿点井田区份为井矿，缓丘高平原区露天矿和河道滩区露天矿三种类型，针对其生产布局特点和环境影响的差异，提出了相应的治理模式。     

A Modeling System for the Evaluation of Water Resources Management Strategies in Thessaly,Greece

A modeling system was developed to evaluate the sustainability of water resources management strategies in the two major basins of Thessaly Region in Greece, namely the Pinios River and the Lake Karla basins. The intense and extensive agriculture of water demanding crops, such as cotton, and the absence of reasonable water resources management have lead to a remarkable water demand increase, which is usually fulfilled by the over-exploitation of groundwater resources. This unsustainable practice has deteriorated the already disturbed water balance and accelerated water resources degradation. The modeling system consists of a hydrological model, a reservoir operation model and methods for the estimation of water demands. The study area was sub-divided into sub-basins and water balance analyses were performed for each sub-basin and each control node of the system for a number of water resources management strategies. Four strategies of hydro-technical project development were coupled with two strategies of groundwater withdrawal and three water demand strategies. In total, more than 24 water management strategies were evaluated. The results showed that, under the existing water resources management, the water deficit of the Pinios River and Lake Karla basins is very large. However, the development of proposed hydro-technical projects in the Pinios River basin coupled with water demand management measures, like improvement of existing water distribution systems, change of irrigation methods, and changes of crop cultivation could alleviate the problem and lead to sustainable and ecological use of water resources in the study area.     

长江流域上游控制性水库群联合防洪调度研究

长江流域水系复杂,防洪对象分布范围广,控制性水库的防洪调度目标具有多元化、分布多区域特征,如何科学运用水库防洪库容,有序兼顾各区域防洪是流域控制性水库群联合防洪调度的关键。选取溪洛渡、向家坝与三峡水库组成的水库群为对象,基于大系统分解协调原理,先通过逐次分解各防洪区域对溪洛渡、向家坝两库预留防洪库容的要求,在结合区域间洪水遭遇关联性分析的基础上,提出两库防洪库容在协调川江与长江中下游两区域防洪中的分配方案;同时对三峡水库的防洪调度方式深入优化,提出适当扩大对城陵矶防洪补偿库容分配方案。研究成果表明,联合调度方案可进一步减少长江中下游分洪量,对于提高整个流域防洪减灾水平,完善长江流域库群防洪调度体系具有重要意义。     

深圳小型水库在现代化城市中的功能效用思考

深圳市小型水库在城市防洪、供水、生态体系中有着重要作用,但其功能效用没有得到很好的发挥。通过分析深圳市小型水库所面临的水库泄洪能力不足、日常管理信息化程度不高、应急应变能力差等问题,提出从法律法规建设、管理系统和自动化建设、应急体系建设、人才队伍建设等方面来加强小型水库管理的建议,以更好地发挥小型水库在现代化城市体系中功能效用。     

浙江省小型水库土石坝病险分析及对策

浙江省共有小型水库3800多座,占水库总数的95．8％,其中土石坝又占小型水库总数的90％以上。通过对全省小型水库土石坝的病险分类和失事原因分析,并有针对性地为千库保安建设标准提供依据。     

The downstream impacts of the burgomillodo reservoir,Spain

The Burgomillodo Dam, located in the middle Rio Duraton (north Spain, Duero Basin), has created a small eutrophic reservoir with a capacity of 15 × 10⁶ m ³ and a maximum depth of 40m. Burgomillodo Reservoir is solely used for producing hydroelectric power. The regulated flow pattern of hypolimnial waters is characterized by higher daytime flows than those by night, with low flows at weekends all the year round. The environmental impact generated by this hydropower scheme on the river downstream was assessed by comparing physiochemical characteristics and aquatic communities of an upstream site (reference station) with those of three downstream stations, which were located 0–2, 2–5, and 7–6 km below the dam. Water temperature, pH and dissolved oxygen were significantly lower downstream from the reservoir. Hardness, alkalinity, suspended inorganic matter, and conductivity had reduced annual variability below the dam. Photosynthetic activity was directly involved in the recovery of dissolved oxygen and pH values. Species richness and abundance of macrophytes increased just below the dam. Macrobenthic and fish communities were composed of higher numbers of potamic species. Number of taxa, density, biomass, and diversity were higher at the reference site, recovering their values as the distance below the reservoir increased. Macrobenthic trophic structure was changed by an increase in predators and filter feeders and a decrease in shredders. Environmental impact values for the macrobenthic community living just below the dam were higher than those for the fish community. It is concluded that the main physiochemical factors involved in environmental impacts were dissolved oxygen deficit and short-term flow fluctuations for the macrobenthic community, and oxygen deficit for the fish fauna. Benthic macroinvertebrates appear to be the best aquatic organisms for detecting changes and for reflecting the spatial recovery of environmental conditions.