Hydropower Exploitation Research Articles

Hydrological responses and adaptive potential of cascaded reservoirs under climate change in Yuan River Basin

AbstractThe ongoing cascading hydropower exploitation in southwestern China has been the subject of debate and conflict in recent years. This study aims to assess the climate change impacts on the hydropower system of Yuan River and to quantify the future potential in operation optimization of Gasa-Madushan (GS-MDS) Reservoir system. The Community Climate System Model version 4 (CCSM4) projections are bias-corrected and downscaled to drive the Soil and Water Assessment Tool hydrological model, aiming to predict the climate and runoff changes for the future. Then, an adaptive operation chart model of cascaded reservoirs is established to balance hydropower generation and ecological requirements under climate change. In the future, the decadal average temperature and annual average precipitation will possibly increase by 0.80–2.22 °C and 2.56–4.65%, respectively; the monthly average runoff may increase by 6.89%, 6.17%, and 18.26% for GS Reservoir Basin, and by 8.89%, 8.14%, and 23.14% for MDS Reservoir Basin under Representative Concentration Pathways (RCPs) 2.6, 4.5, and 8.5, respectively. The adaptive operation chart results in a reduction of 52.66–70.77% in the total water shortage at a cost of 2.09–4.54% decrease in total power generation of the GS-MDS cascaded hydropower system compared to that of non-adaptive operation chart.

Combined Flow Abstraction and Climate Change Impacts on an Aggrading Alpine River

AbstractRecent climatic warming and associated glacial retreat may have a large impact on sediment release and transfer in Alpine river basins. Concurrently, the sediment transport capacity of many European Alpine streams is affected by hydropower exploitation, notably where flow is abstracted but the sediment supply downstream is maintained. Here, we investigate the combined effects of climate change and flow abstraction on morphodynamics and sediment transfer in the Borgne River, Switzerland. From photogrammetrically derived historical Digital Elevation Models (DEMs), we find considerable net aggradation of the braided river bed (up to 5 m) since the onset of flow abstraction in 1963. Reaches responded through bed level steepening which was strongest in the upper most reach. Widespread aggradation however did not commence until the onset of glacier retreat in the late 1980s and the dry and warm years of the early 1990s. Upstream flow intake data shows that this aggradation coincided with an increase in sediment supply, although aggradation accounts for no more than 25% of supplied material. The remainder was transferred through the studied reaches. Estimations of bed load transport capacity indicate that flow abstraction reduces transport capacity by 1–2 orders of magnitude. While residual transport rates vary with morphological evolution, they are in the same order of magnitude as the sediment supply rates, which is why significant transport remains. However, the reduction in transport capacity makes the system more sensitive to short‐term (annual) changes in climate‐driven hydrological variability and climate‐induced changes in intake management and sediment delivery rates.

Smart Design and Development of a Small Hydropower System and Exploitation of Locally Sourced Material for Pelton Turbine Bucket Production

Small hydropower (SHP) systems are known to be an environmentally friendly, cost-effective and simple form of renewable energy production, appropriate for rural and standalone electrification. Greater access to power in sub-Saharan Africa (SSA) can be facilitated through domestic design and development of SHP components and systems. Domestic participation in the design, manufacturing of SHP components and application of SHP systems can be promoted through SHP capacity building and the use of locally sourced materials. This study, therefore, involves the design of both civil and mechanical aspects of SHP, and the use of locally sourced materials and manufacturing processes, in the design and production of Pelton turbine buckets. The study succeeded in the coding of a SHP system design and the development of design charts using MATLAB. A390 and A390-5 Mg cast aluminium alloys were selected and investigated as Pelton bucket materials using Solidworks modelling and simulation software. The performance of the materials as measured by von Mises, displacement and strain results were outstanding: the probe maximum stress was 6.7 × 107 N/m2, located along the splitter; the FOS was 4.5; fatigue damage and load safety for fully reversed loading at 106 cycles were 0.001 and 2.03, respectively.

Ecological footprint analysis of environmental impacts by cascaded exploitation of diversion-type small hydropower: a case study in southwest china

Cascaded exploitation of diversion-type small hydropower (SHP) offers a source of new energy as well as socioeconomic benefits; however, it inevitably causes environmental disturbance and damage. Previous studies on the cumulative effect of cascaded diversion SHP rarely discussed using quantitative analysis method. In this paper, the ecological footprint analysis approach is proposed to assess the positive and negative impacts of cascaded diversion SHP on environment of a small-scale river in Southwest China. Positive impact is defined as ecological supply footprint (ESF), which refers to vegetation protection by replacing firewood with SHP. Negative impact is defined as ecological loss footprint (ELF), which includes fish and net primary productivity loss, vegetation destruction and soil erosion. With the raising in the number (n>4) of diversion SHP stations, the difference between ELF and ESF increases remarkably, suggesting that the adverse impacts of cascaded diversion SHP accumulate in the study area. Compared with vegetation destruction and soil erosion, the cumulative loss of fish and net productivity is the most important aspect of the adverse impacts which needs more attentions.

Green small hydropower in China: Practices and drivers

After more than one hundred years of development, the small hydropower (SHP) development rate of China has reached 58% with limited potential for hydropower exploitation in many provinces. In addition to the challenges of safety, efficiency, and social benefit-sharing, the environmental impact has become a tough challenge for the development of SHP in China. Based on successful experiences with green hydropower certification internationally [Bratrich et al., River Res. Appl. 20(7), 865–882 (2004); Low Impact Hydropower Certification Program (Low impact Hydropower Institute, New Jersey, USA, 1999); and Hydropower Sustainability Assessment Protocol (IHA, London, UK, 2010)], Green Small Hydropower [Yu et al., Water Power 33(7), 1–4 (2007)] (GSHP) certification has been proposed in China. The goal is to find the balance between river conservation and renewable energy production. With the introduction of the status quo and challenges of the development of SHP in China, practices of GSHP in China have been summarized, covering the transformation of development philosophy, GSHP assessment, policy improvement, and technical progress. Furthermore, this paper illustrates the major drivers of GSHP, which include the increasing awareness of environmental protection, change of supply and demand balance, and weak regulatory framework. Finally, this paper points out the priorities and suggestions for future work.

Runoff and Sediment Response to Cascade Hydropower Exploitation in the Middle and Lower Han River, China

With the rapid development of hydropower exploitation in China, changes in runoff and sediment transport have become a significant issue that cannot be neglected. In this study, the Han River was selected as a study case, where the runoff variation and changes in sediment load at the Baihe, Huangjiagang, Huangzhuang, and Xiantao stations were analyzed in different time periods. The results indicate that impact of cascade hydropower exploitation on runoff and sediment transport is significantly different even during the same time periods. After reservoir regulation, the decreasing of sediment load is faster than that of runoff. Strong positive correlation between runoff and sediment load exists during different time periods, while reservoir operation leads to different turning points at the Baihe, Huangjiagang, Huangzhuang, and Xiantao stations in the middle and lower Han River. As a key driving factor, runoff variation contributed to sediment transport with different impact indexCR. The impact indexCRbefore and after the first change point at the Baihe, Huangjiagang, Huangzhuang, and Xiantao stations is 43.35%, −3.68%, 11.17%, and 30.12%, respectively. This study helps us understand and evaluate the hydrological changes under cascade hydropower exploitation in the middle and lower Han River.

Использование методики гидроэкологического мониторинга при анализе гидроэнергетических и ирригационных сооружений Узбекистана

The article is devoted the issue of cre-ating the geoinformation systems for hydroecological monitoring as a support tool for information systems in the Aral sea basin and the optimization models in the development of environmentally acceptable modes of operation of hydraulic structures. In this scientific work presents the experience of works on creation of geoinformation systems using remote methods La information support, with a study of the technical parameters of the hydropower and irrigation facilities on the pool level of the river Amudarya and Syrdarya. The results allow to organize a more rational use and conservation of land and water resources with sustainable exploitation of hydropower and irrigation structures of Uzbekistan.

Climate change sensitivity of threatened, and largely unprotected, Amazonian fishes

Abstract Climate change is poised to have fundamental impacts on the freshwater environments of the Amazon River Basin, and protected areas are routinely proposed as a possible management strategy to conserve freshwater fishes. However, there remains a paucity of information regarding the sensitivity of threatened fish species to climate‐induced changes in water quantity and quality. An expert‐based survey was used to address the following questions: (1) Are currently threatened fish species in Brazil also sensitive to projected effects of climate change? (2) Does the current conservation status of fish species also reflect their degree of sensitivity to climate change? and (3) What are the specific aspects of climate change that are likely to contribute the most to species sensitivity? Survey respondents evaluated 35 species (11 families) representing 50% of the threatened species in the Brazilian Amazon. The results suggest that the majority of threatened Brazilian fish species are considered highly sensitive to climate change impacts. Climate‐induced changes in water quality were, on average, considered a greater threat to species persistence than potential changes in water quantity. Survey results also suggest that fishes exhibit high sensitivity to changes in temperature and dissolved oxygen, and moderate to high sensitivity to changes in high‐flow (i.e. flood) and low‐flow (i.e. drought) regimes. A considerable mismatch was found between species conservation status and sensitivity to climate change, suggesting that perceptions of present‐day extinction risk do not necessarily provide insight into future risks associated with climate change. Species sensitivity to climate change showed no relationship to dispersal ability, indicating that protected areas may serve as important refugia for those species unable to keep pace with climate change. Despite this, the number and size of protected areas in Brazil have decreased over the past decade, largely to support the exploitation of hydropower and mining. Strategic conservation planning that involves existing and new protected areas for those species most at risk to climate change is warranted. Copyright © 2016 John Wiley & Sons, Ltd.

Hy:Con: A Strategic Tool For Balancing Hydropower Development And Conservation Needs

Hydropower (HP) is an important renewable energy source contributing 65.7% to Austria's national electricity generation. However, HP is also associated with ecosystem degradations jeopardizing the aims of the EU Water Framework Directive (WFD) and Habitats Directive. Based on the EU Renewable Energy Directive (RED), the Austrian Energy Strategy has defined goals to further increase HP production by 3.5 TWh until 2015. Because national strategies for HP development are widely missing, hydropower plants (HPPs) are planned and approved on a local and regional level, often neglecting the overall optimum for energy supply and ecology. Therefore, a decision support tool (Hy:Con) was developed to integrate the energy-economic characteristics of planned HPPs and conservation needs of ecologically sensible river stretches. Based on 102 planned HPPs in Austria, Hy:Con identified HPPs with high economic attractiveness and low conservation concerns. The results show that owing to the already high HP exploitation in Austria, only a minor number of projects are without conservation conflicts. Upgrading of existing HPPs was associated with least ecological impacts, while HPPs with reservoirs are favoured over run-of-river plants. Cumulated ecological effects of numerous small HPPs are significant, whereas their contribution to overall energy production is comparatively small. Hy:Con represents a strategic instrument that can help decision makers to govern the implementation of the RED and WFD in a transparent way to pinpoint the limitations of future HP development and to avoid conflicts and stranded investments. © 2015 The Autors. River Research and Applications Published by John Wiley & Sons Ltd

Comparison between natural and impacted Alpine lakes six years after hydropower exploitation has ceased

AbstractMany lakes in mountain regions have been used for hydropower generation since the 1950s. It has been estimated that as many as 79% of the rivers in the Alps have been affected by the presence of hydropower plants. In this context, the shutting down of hydropower plants on a group of Alpine lakes represented a good opportunity to study the ecological impact on them. We selected nine lakes that had been affected and nine that had not, and analysed the differences in environment, littoral diatoms and zoobenthos, phytoplankton, zooplankton, and fish. Results showed that benthic biota -diatoms and zoobenthos- were the most affected by water-level drawdown during winter months. Even six years after the end of hydroelectric operations, diatom species richness and diversity were lower in impacted lakes. Assemblage structure was different for both diatoms and zoobenthos. Phytoplankton and zooplankton were similar in impacted and unaffected lakes in terms of both species richness (and diversity) and assemblage structure. The degree of impact on fish was unclear because illegal stocking of lakes with allochthonous fish species had taken place. This study showed that compared to limnetic biota, littoral communities were the most affected by the decrease in water volume every winter. Six years after the end of hydroelectric operations, diatoms, and to lesser extent zoobenthos, were still different compared to those in natural (unaffected) lakes. Planktic communities seem to be either more resistant to the disturbances, or else able to recover more quickly to their former condition.

Watermills in the historic irrigation system ‘Palmeral de Elche’, Spain: an example of early hydropower exploitation

With more than 180,000 date palms, the Palmeral de Elche is the largest palm grove in Europe. In 2000, United Nations Educational, Scientific and Cultural Organization (UNESCO) declared a part of it a World Heritage Site. Actually, the Palmeral is a historic irrigation system with rows of palm trees flanking rectangular fields and serving as a windbreak and shade for the cultivation of wheat, alfalfa, fruit trees and vegetables. This system and its cultivation methods were mainly developed during the Islamic period and maintained after the Christian Reconquista in 1265 until recently. The main canal Acequia Mayor supplies irrigation water from the Vinalopó River which is then distributed through secondary canals to the different subsystems and fields as well as for domestic purposes. With an average slope of 1:260 (4‰) the main canal has a flow capacity of about 600 L/s. Owing to the topography, the canal must overcome a number of vertical drops where hydraulic energy must be dissipated. Beside the drop structures, at the same time watermills generate water power for flour production. These watermills have been built since the Islamic era and operated until the last century, when they were abandoned or converted for other uses. There are some descriptive publications and documents dealing with the mills, but there has not yet been any attempt to conduct a technical survey and interpretation. This study explores the remains of 11 watermills and determines the dimensions and technical parameters of this hydro-system. The mills were equipped with turbine-type horizontal waterwheels with hydraulic heads between two and more than 15 m. The observations allow conclusions on mill operation, power yield and flour production. A comprehensive description of this early example of waterpower generation in a multipurpose system is undertaken.

Climate change impacts on bedload transport in alpine drainage basins with hydropower exploitation

AbstractSediment transport is known to have a significant impact on hydropower infrastructures and changes in sediment transport rates are important for sediment management measures and hydroelectricity production. In this study, we present how climate change may affect bedload transport in 66 high alpine catchments used by hydropower companies in the Valais, Switzerland. Future sediment yield is estimated with a runoff‐based sediment transport model for the two future 30 year time periods 2021–2050 and 2070–2099. The analysis is integrated into a modelling chain in which error‐corrected and downscaled climate scenarios generated in the framework of the ENSEMBLES project are coupled to the hydrological model PREVAH, glacier retreat and bedload transport. To calibrate the sediment transport model, we used the observed sediment volumes in water intakes and reservoirs if such data were available. The results obtained show on average a decrease of sediment yield due to the reduced runoff generation during summer, especially for the scenario period 2070–2099. A shift of the seasonal sediment transport regime with a current maximum during July and August to earlier months in the year is predicted. Projections of future sediment yield rely on the accuracy of the individual modeling chain elements. The different sources of uncertainty are discussed qualitatively. Copyright © 2015 John Wiley & Sons, Ltd.

Study on the Variation of Landscape Pattern under the Influence of Hydroelectric Development: A Case Study of Madushan Hydropower Station, China

Based on 3S Technology, this paper mainly focuses on studying temporal dynamic changes of landscape pattern in the upper reaches of the Madushan of Yunnan Province before and after the construction of Madushan hydropower station. From 2006 to 2011, the woodland area showed a downward trend, while those of some savanna, cropland, bench land, residential land, transportation land and industrial land were in adverse circumstances. The woodland area dropped from 1374.37km 2 to 1230.88 km2 by 10.4% compared to 2006. The water area increased from 6.99 km2 in 2006 to 11.72 km2 in 2011. What's more, some inter-transitions between different landscape types were also frequent, especially for woodland, cropland and savanna. Actually, the integrated variation of landscape degree was 6.2%. And all the landscape types presented a growing trend except for woodland. The fastest trend was 26.3% in industrial land, the slowest trend was 0.4% in cropland. In conclusion, there was an apparent change in the landscape pattern for the study area before and after the hydropower station construction, and this study could be significant for better understanding of the landscape ecological effects of hydropower exploitation.

How many more dams in the Amazon?

The Amazon watershed harbors a megadiversity of terrestrial and aquatic plants and animals. Mechanisms that sustain this biodiversity are the water level fluctuations the fluvial dynamics and the intense gene flux due to permanent integration of climatological, geomorphological and biological components of the system. The construction of hydroelectric reservoirs to support economic development of Brazil and other countries that share the Amazon basin will interfere with the ecological dynamics of this ecosystem changing the hydrological, hydrosocial and fundamental processes. Furthermore the construction of Andean reservoirs can disrupt the connectivity with the lower Amazon ecosystem. Principles of ecohydrologies, ecological engineering and preservation of key river basins, have to be applied in order to optimize energy production and promote conservation practices. Long term planning and integration of countries that share the Amazon basin is a strategic decision to control and develop the hydropower exploitation in the region.

Influence of a reservoir chain on the transport of riverine inorganic carbon in the karst area

The Wujiang River is an important tributary to the Changjiang River that has been intensively impounded for hydropower exploitation. To understand the potential impact of reservoir construction on the riverine inorganic carbon transport, seasonal longitudinal sampling was conducted in four reservoirs Hongjiadu (HJD), Dongfeng (DF), Suofengying (SFY) and Wujiangdu (WJD) along the Wujiang River from April 2006 to January 2007. Results indicated that damming the river induced an obvious discontinuity of water chemistry in the warmer seasons. δ 13C of dissolved inorganic carbon (DIC) ranged from −3 to −11.4 ‰, likely as the results of photosynthesis, respiration and carbonate weathering. During periods of thermal stratification, the addition of CO2 from respiration to hypolimnion and the deep water release for hydropower generation led to higher pCO2 downstream, as well as 13C depletion in DIC and undersaturated to calcite. An estimate of DIC budget indicated that only DF reservoir was the sink for DIC while reservoirs HJD, SFY and WJD were the sources for DIC. However, when the retained water was taken into account, for the reason of water storage occurring mainly in HJD and DF, all reservoirs became the sources for DIC with exporting rates of 26.68, 7.97, 6.22 and 11.80 % for HJD, DF, SFY and WJD, respectively.

Opportunities from low-resolution modelling of river morphology in remote parts of the world

Abstract. River morphodynamics are the result of a variety of processes, ranging from the typical small-scale of fluid mechanics (e.g. flow turbulence dissipation) to the large-scale of landscape evolution (e.g. fan deposition). However, problems inherent in the long-term modelling of large rivers derive from limited computational resources and the high level of process detail (i.e. spatial and temporal resolution). These modelling results depend on processes parameterization and calibrations based on detailed field data (e.g. initial morphology). Thus, for these cases, simplified tools are attractive. In this paper, a simplified 1-D approach is presented that is suited for modelling very large rivers. A synthetic description of the variations of cross-sections shapes is implemented on the basis of satellite images, typically also available for remote parts of the world. The model's flexibility is highlighted here by presenting two applications. In the first case, the model is used for analysing the long-term evolution of the lower Zambezi River (Africa) as it relates to the construction of two reservoirs for hydropower exploitation. In the second case, the same model is applied to study the evolution of the middle and lower Paraná River (Argentina), particularly in the context of climate variability. In both cases, having only basic data for boundary and initial conditions, the 1-D model provides results that are in agreement with past studies and therefore shows potential to be used to assist sediment management at the watershed scale or at boundaries of more detailed models.

The Legal Regulation of the Small-Scale Rural Hydropower

The source of small-scale rural hydropower in our country is numerous. The exploitation and construction of small-scale hydropower plays a vital part in the economy, environment and ecology in our rural area. Meanwhile, the experience which we have learnt has promoted the development of small-scale hydropower in the whole world. However, there still exist certain problems. This thesis has summed up those problems, and gives some legal regulations. In this way, the small-scale rural hydropower would make a big impact in our country.

Evaluation Research about the Post Environmental Impact Assessment of Cascade Hydropower Engineering which Based on Matter-Element and Analytic-Hierarchy Coupling Model

The environmental post evaluation index system is proposed to evaluate the cascade hydropower project`s post environmental impact assessment. We also constructed an evaluation method based on Matter-element and Analytic-hierarchy coupling model (FME-AHP) to apply to the environmental impact assessment of Yuan Shui cascade hydropower stations. It can test the index system and evaluation method is scientific and validity or not. We hope we can provide some experience and reference for the environmental impact assessment of the hydropower exploitation in key river basin both in China and abroad.

Water Quality Assessment of Gufu River in Three Gorges Reservoir (China) Using Multivariable Statistical Methods

To provide the reasonable basis for scientific management of water resources and certain directive significance for sustaining health of Gufu River and even maintaining the stability of water ecosystem of the Three-Gorge Reservoir of Yangtze River, central China, multiple statistical methods including Cluster Analysis (CA), Discriminant Analysis (DA) and Principal Component Analysis (PCA) were performed to assess the spatial-temporal variations and interpret water quality data. The data were obtained during one year (2010~2011) of monitoring of 13 parameters at 21 different sites (3003 observations), Hierarchical CA classified 11 months into 2 periods (the first and second periods) and 21 sampling sites into 2 clusters, namely, respectively upper reaches with little anthropogenic interference (UR) and lower reaches running through the farming areas and towns that are subjected to some human interference (LR) of the sites, based on similarities in the water quality characteristics. Eight significant parameters (total phosphorus, total nitrogen, temperature, nitrate nitrogen, total organic carbon, total hardness, total alkalinity and silicon dioxide) were identified by DA, affording 100% correct assignations for temporal variation analysis, and five significant parameters (total phosphorus, total nitrogen, ammonia nitrogen, electrical conductivity and total organic carbon) were confirmed with 88% correct assignations for spatial variation analysis. PCA (varimax functionality) was applied to identify potential pollution sources based on the two clustered regions. Four Principal Components (PCs) with 91.19 and 80.57% total variances were obtained for the Upper Reaches (UR) and Lower Reaches (LR) regions, respectively. For the UR region, the rainfall runoff, soil erosion, scouring weathering of crustal materials and forest areas are the main sources of pollution. The pollution sources for the LR region are anthropogenic sources (domestic and agricultural runoff, hydropower exploitation and municipal waste). The study demonstrates the utility of multivariate statistical techniques for river water quality assessment, identification of pollution sources, and exploring spatial and temporal variations of water quality.

WATER-ECONOMIC PROBLEMS IN NORTHEASTERN MONTENEGRO

The paper discusses the problems of water economic northeastern Montenegro municipalities Berane, Andrijevica and Plav. It points to the problem of exploitation of water, protection of water and water protection. Within exploit water resources, the possibilities of water supply of population and industry, water supply, agriculture, hydropower exploitation, tourism and recreational use. Current and future use of water resources considered GeoScape, requires a new approach, which should be in accordance with the concept of active protection of the environment.