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The reservoirs play a crucial role in the development of civilization as they facilitate the storage of water for multiple purposes like hydroelectric power generation, flood control, irrigation, a...

Dams must provide human development with economic viability, social equitability, and be environmentally sustainable However, environmental and social impacts are often negative and seldom considered in the design of these projects. We made a multitemporal analysis classifying 26 satellite images of several Mexican hydroelectric power stations between 1972 and 2016 to evaluate the effect of dams on the change in land use. Eleven socio-economic indicators were also compared before and after the construction of the dam to document effects on local communities. We use the Land Change Modeler to quantify the net changes in land use and land cover. We found a mean decrease in tropical forest (1,404.19 km2) and temperate forest (1,191.26 km2) and an increase in agriculture (2,241.26 km2) and urban use (92.9 km2). The results also show that although some indicators improved, the environmental deterioration around these projects shows that they are not sustainable.

Hydroelectric projects are often pursued on the promise of economic development and environmental co-benefits as a source of low-carbon energy. We analyse the case of the Muskrat Falls hydropower mega-project (located in Labrador, Canada) to understand why this project failed to live up to its promised benefits, but instead delivered a double disaster of economic cost and environmental risk. The key concepts of anti-reflexivity and deep stories help us understand why the project assumed an aura of inevitability in political and public discourse until it was too late to change course. Drawing on publicly available data and secondary sources, we identify the constellation of social forces that maintained political anti-reflexivity about the economic and environmental risks of the project and led to a double economic and environmental disaster. Our analysis identifies vital lessons for countering anti-reflexivity and improving environmental governance related to energy mega-projects.

We employed statistical techniques to assess the quality of surface water measured before and after filling the reservoirs of four important hydroelectric power plants (HPPs) established in the Brazilian Amazon (Belo Monte, Jirau, Teles Pires, and Santo Antonio do Jari). A cluster analysis efficiently identified distinctions between the dendrograms obtained for the pre- and post-filling phases in the four projects and indicated changes in water quality after the reservoirs were filled. The Mann-Whitney U test (at the 5% significance level) allowed for the identification of parameters that exhibited significant changes after filling the reservoirs. Across the four HPPs, a total of 45 monitoring points and 54 water quality parameters were analyzed. The results revealed 14 parameters that changed significantly at a greater number of monitoring points in more than one HPP, namely water temperature, pH, dissolved oxygen, electrical conductivity, oxidation-reduction potential, transparency, total dissolved solids, chlorophyll-α, thermotolerant coliforms, alkalinity, total phosphorus, and calcium, sulfate, and sulfide ion concentrations. These parameters were identified as the most important for explaining the changes in water quality after filling the reservoirs. All monitoring points located within the reservoirs (41 points) and immediately downstream of the dams (4 points) revealed significant changes in water quality. Thus, changes in the quality of surface water were observed along the entire lengths of the reservoirs, including the initial stretches. This study contributes to the understanding of the temporal and spatial effects of the formation of reservoirs on surface water quality parameters.

Downstream of hydroelectric plants, hydropeaking can cause frequent flow variations, resulting in habitat modifications (e.g. hydraulics, reach morphology, temperature, water quality), which can im...

Although storage-reliability-yield (SRY) relationships have been widely used in the design and planning of water supply reservoirs, their application in hydroelectricity is practically nil. Here, w...

Small hydroelectric power (SHP) facilities are proliferating around the world, including in Brazil where legislation encourages SHP over other hydropower development, defining SHP as facilities with installed capacities of 3–30 MW and reservoirs

This research was performed to optimize the performance characteristics of the Nigerian Jebba Hydropower Plant in order to enhance its generation of electricity. Pertinent hydropower data were hour...

Altered rivers and managed flows are a hallmark of civilization and dams are a principal agent of alteration. Peak dam construction occurred at the turn of the last century in Western countries, and many of the largest dams are reaching the end of their service life. As a result, dam operators are increasingly facing a complex renewal/removal decision‐making process in a large part because the economic and social values of dams have changed. The Mactaquac Hydroelectric Generating Station (New Brunswick, Canada), operated by NB Power Corporation (NB Power), is Canada's 25th largest dam and it is reaching the end of its service life. A decision is required for the dam's future state and three options were originally proposed: renew, rebuild, or remove. An overarching science framework was developed with NB Power to inform and support decision‐making for the dam's decision process and an impending Environmental Impact Assessment. The framework guides research and monitoring for dam renewal/removal using science‐based solutions that aim to minimize impacts on the aquatic environment while supporting an efficient and cost‐effective decision‐making process. The framework has five components: (a) establish long‐term baselines of environmental conditions; (b) develop normal ranges describing the river's natural variability; (c) integrated physical and biological modelling; (d) assess the specific and cumulative state of fish passage; and (e) create and sustain a user‐friendly geospatial data management system. In this paper we present a case study that implements the science framework (Part 1) through the Mactaquac Aquatic Ecosystem Study (MAES) with a view to revisit and assess its final impact post‐project completion (Part 2).

This paper attempts to design statistical models to forecast annual precipitation in the Neuquen and Limay river basins in the Comahue region of Argentina. These forecasts are especially useful as ...

Even in the twenty-first century, myths of preindustrial forms of energy utilization are woven around watermills, waterwheels, and traditional millscapes. Along German watercourses, many grinding shops and hammer mills held on to waterwheels and delivered mechanical rather than electric power well into the twentieth century. It is not the case that the days of these “old technologies” (Edgerton 2008) were numbered as soon as hydroelectricity and “modern” hydraulic turbines appeared in the 1880s. When analyzing the dominating contemporaneous discourses around hydropower, it is easy to overlook these tendencies of historical persistence. This is not surprising, considering that scientific, literary, and preservationist narratives around 1900––actively and subtly––propagated and spread the idea ofMuehlensterben, or the myth of dying watermills that has been rehearsed over and over again in reflections on hydropower history. In this article, we challenge the popular imaginaries of “old” and “outmoded” watermills in a two-step approach. Firstly, we contrast the well-known transition at the advent of hydroelectricity with hydropower activities, which took place simultaneously in Germany’s traditional commercial landscapes. Here, waterwheels remained in good use, despite the electrification and scientific development of hydraulic turbines. Secondly, we deconstruct the romantic bias towards the preindustrial symbolism of the waterwheel by analyzing different arguments in professional journals as well as romanticizing and nostalgic literature. We combine approaches and empirical material of both historical and literary sciences to gain a better understanding of how different narratives reinforced the image of watermills and waterwheels being outdated. In this respect, the interdisciplinary approach contributes to the emerging field of theEnvironmental Humanities.

Quantifying the downstream survival of migrating fish past dams is critical for conservation efforts. Regulators require assessments of survival as a condition of operation. Failure to meet an established survival standard may result in required operational or costly structural changes at a facility. Establishing the survival standard, as well as the rules of assessment, is a point of contention between regulators and operators. Management goals are based on biological criteria, but there are inherent statistical and probabilistic trade‐offs when choosing a standard value and the method for assessment. We make a distinction between a “biological” goal (the conservation goal) and a “statistical” standard (a function of the biological goal, sample size, assessment method, and years of consecutive evaluation). An effective statistical standard maximizes true positives (passing the standard when the biological goal is being met) and true negatives (failing the standard when the goal is not being met), while minimizing false negatives and false positives. We explored the effects of sample size, true survival, and assessment methods on the probability of passing different statistical standards by simulating survival studies (simulating mark‐recapture experiments). We observed a strong influence of assessment methods on the probability of making the right decision (true positive or true negative), especially when sample size, and recapture probability was low. As a support tool, we developed an interactive user interface to explore specific scenarios, and to aid communication among decision‐makers.

There are 104 hydroelectric facilities proposed to be installed in the watersheds that feed the Pantanal, a vast floodplain wetland located mostly in Brazil. The Pantanal is host to 23 long‐distance migratory fish species that ascend upland tributaries to spawn. A Geographic Information System was used to predict the impact of hydroelectric dams on potential migration routes for these species. Both anthropogenic (hydroelectric dams) and natural barriers were included in the analysis. Natural barriers were identified by river slope. Critical river slopes of 10 and 25%, above which fish were predicted to be incapable of ascending, were modeled as natural barriers. Based on this model, we show that between 2 and 14% of rivers in the Pantanal watershed are naturally blocked to fish migration. An additional 5 to 9% of rivers are currently blocked due to 35 existing hydroelectric facilities. If all proposed dams are built, the area flooded by new reservoirs will triple and the river kilometers blocked will double, blocking 25 to 32% of the river system to fish migration. The Taquari and Cuiaba River sub‐basins will be the most impacted, each having more than 70% of their rivers blocked. The impact of individual proposed facilities on the loss of migration routes is related to their proximity to existing barriers. Fourteen of the proposed dams are upstream from existing barriers and will therefore not further restrict long‐distance fish migration routes while proposed dams are predicted to close an additional 11,000 to 12,000 km of river channels.

Extreme climatic events, such as flooding and drought, can abruptly modify the amplitude of the river level of a river, promoting new environmental conditions and impacting aquatic communities. Furthermore, an increasing frequency of extreme droughts in dammed rivers is expected because dams homogenize the flood pulse and decrease the river level. In this study, we evaluated the effects of extreme river-level oscillations on the benthic macroinvertebrate communities in a floodplain river. We analysed 47 years of river-level data and 17 years of benthic macroinvertebrate data. Our findings indicated that (1) extreme river-level oscillations promoted environmental conditions that were distinct from the regular oscillation; moreover, environmental characteristics were more heterogeneous in extreme oscillations than regular oscillations; (2) extreme oscillations were associated with a decreased richness, density, and diversity of benthic macroinvertebrates, promoting the dominance of tolerant taxa. Furthermore, in the studied river, a large hydroelectric power plant was built 19 years ago, which (3) decreased the river-level downstream, accentuating the occurrence of extreme drought, which has become more common after damming. We emphasize the importance of long-term biological monitoring considering the more frequent occurrence of extreme river-level oscillations in response to factors such as dam building and climate change.

To enable prioritization among measures for ecological restoration, knowing the expected benefits and consequences of implementation is imperative but rarely explicitly quantified. We developed a novel method to prioritize among environmental flow measures to rehabilitate ecosystems in the Ume River catchment in northern Sweden, a river system heavily regulated for hydropower production. Our strategy was to identify measures with minimal impact on hydropower production while providing substantial environmental benefits. Based on field surveys of remaining natural values and potential for ecological rehabilitation, we quantified the projected gain in habitat area of implementing environmental flows for target organism groups, for example, lotic fish species and riparian vegetation, along the whole river length. We quantified the consequences for hydropower production by identifying a set of hydropower operational rules reflecting the constraints added by environmental flows. We then used production optimization software to calculate changes in hydropower production and revenues. Implementing restrictions on zero-flow events by mandating minimum discharge at all run-of-river hydropower stations and allocating 1%–12% of mean annual discharge to bypassed reaches in the entire catchment would result in a 2.1% loss of annual electricity production. Adding flow to fishways would increase the loss to 3.1% per year. With implementation of more natural water-level fluctuations in run-of-river impoundments, the loss increases to 3.8%. These actions would increase the habitat for lotic species like the grayling Thymallus more than threefold and increase the area of riparian vegetation by about 66%. Our method forms a basis for ongoing implementation of nationwide environmental rehabilitation schemes. Originally included in thesis in manuscript form.

The Santo Antonio is the fifth largest hydro plant in Brazil. Due to the environmental constraints, the plant follows a run-of-river operation and, to handle inflow variability, possesses t...

The need for reducing the CO2 emissions and fossil fuel dependence of several countries generated a growing interest for the Renewables. The Caribbean Sea is characterized by persistent and high magnitude winds, which suggest an important source of offshore wind energy. Recent studies reported that the Colombian Caribbean has a relevant opportunity for developing the offshore wind technology which could complement the energy production when the hydroelectric system is under low generation due to persistent dry conditions generated by El Niño events. The offshore wind energy may complement the energy offer of Colombia. Hence, understanding the impact of climate variability events in the Caribbean over the wind magnitude, contributes to the knowledge of the resource availability for a better planning of future offshore wind farms. In this sense, this study analyzed 39 years of Reanalysis wind data through a time series analysis of the Caribbean to identify the lowest wind speed velocities and when and why they occurred. The results showed that winds of the study area represented by the Caribbean Low level, showed the lowest wind speeds in the short, mid, and long term due to the influence of the seasons, El Niño-Southern Oscillation (ENSO) and the Atlantic Multidecadal Oscillation (AMO).

This study presents a process that uses the method of alliances, conflicts, tactics, objectives, and recommendations (MACTOR) to inform integrated water resources management (IWRM) strategi...

The current theme is the impact that the awareness of the non-stationarity of hydrological phenomena, and of river hydrology in particular, has on hydraulic engineering and hydropower [...]

In the second half of the twentieth century, a cascade of reservoirs was constructed along the Angara: Irkutskoe, Bratskoe, Ust-Ilimskoe and Boguchanskoe, which were intended for producing renewable hydroelectric energy for providing transportation through the Angara and Yenisei Rivers, and for avoiding floods. The upper reservoir (Irkutsk Dam) is used to regulate the level of Baikal Lake. The cascade of Angarsk reservoirs is managed using the dispatch schedules developed in 1988. This article contains a multi-criteria analysis of the “Lake Baikal–Irkutsk Reservoir” operating modes in a changing climate, based on statistical summaries of performance criteria: reliability, resilience, vulnerability. Studies have shown that dispatch schedules need to be developed on the historical series of recent years, updated more often and optimization methods should be used for real-time management. This article discusses mathematical methods, algorithms and their implementations for the formation of reservoir operation modes based on dispatch schedules (DS) and optimization methods. Furthermore, mathematical methods, algorithms and programs have been developed for the formation of reservoir operation modes in real time, based on optimization approaches and long-term series of observed inflows, taking into account a given hierarchy of priorities of water users’ requirements. To solve the integer nonlinear large-dimensional task of performing water resource calculations, a special optimization algorithm was developed that allows decomposition of the task into a series of two-year dimensional independent subtasks.

To balance the water demands of different departments and produce a win–win result for reservoir operation, a series of conflict-resolution methods have been developed to define the socio-optimal operation strategy for specific conflict problems. However, given the inherent uncertainty of reservoir operation brought by climate change, the compromised strategies selected by conflict-resolution methods can vary. Therefore, quantifying the impacts of climate change on the decision characteristics of conflict-resolution methods can help to address questions about whether conflict-resolution decisions are sustainable given unforeseen changes. In this study, the Yangtze River is regarded as study area. As a world-class hydropower project located on the midstream of Yangtze River, Three Gorges Hydroelectric Power Station can transfer plenty of water energy into electricity. To alleviate the ecological water shortage caused by hydropower operation, sustainable and balanced operation strategies considering the water demands of two departments needs to be studied. In the context of hydropower-environmental conflict-resolution management, the decision behaviors of two fuzzy social choice methods and four game-theoretical bargaining methods under 25 kinds of future climate scenarios are analyzed. Comparing the strategy selection results of different methods for a future period (2021–2082) shows that in all proposed climate scenarios, the decisions of the Nash bargaining method, alternating offer method, and unanimity fallback bargaining method in game-theoretical bargaining methods are more stable than other studied methods, which means that climate change affects the decision behaviors of these three methods slightly. In addition, balanced strategies selected by these three methods could formulate adaptable reservoir operation policies that would satisfy the interests of hydropower and environmental stakeholders equally, and avoid a very low satisfaction level of individual stakeholder and whole stakeholders in the water-conflict year. Therefore, against the background of an increasing demand for environmental protection, these three methods can provide socio-optimal strategies considering social and economic benefits for water resource management.

The water rights analysis package simulates surface water development, allocation, management, and use and performs reliability and frequency analyses of simulation results. The computer modeling system facilitates assessments of hydrologic and institutional water availability and reliability in satisfying requirements for reservoir storage, water supply diversions, environmental instream flows, and hydroelectric energy generation. Reservoir system operations for flood control can be simulated. Capabilities are also provided for tracking salinity concentrations. Basin-wide impacts of water resources development projects and management practices are modeled. The modeling system is generalized for application anywhere, with input datasets being developed for particular river systems of concern. The water availability modeling system maintained by the Texas Commission on Environmental Quality and routinely applied by the professional water management community consists of the water rights analysis package and simulation input datasets for all of the river basins of Texas. Model-users modify the input datasets as appropriate to evaluate alternative water use scenarios, development projects, and management strategies of interest. This paper explores concepts and methodologies incorporated in the water rights analysis package and other comparable modeling systems, implementation of water availability modeling in Texas, and contributions to effective water management., Texas Water Journal, Vol. 12 No. 1 (2021)

The penetration of multiple integrated renewable energies to the power grid are relevant for decision making in energy policy, environment and business. Such an electricity penetration is affected by the intermittent and volatile characteristics of integrated energies, mostly significantly related to the safe and stable electricity production and supply in real world. Here, this paper focuses on the low frequency oscillation analysis of the hydropower generation response to the wind and solar variability. To enable this analysis, a hybrid model of hydropower system integrating with the wind and solar power system is presented. The Nyquist and root-locus stability methods are used to investigate the sensitivity performance of the hydropower governor to the fluctuation of the integrated renewable energies. Additionally, to quantify the risk of the hybrid system, the low frequency oscillation response of hydropower system to wind/solar/hydropower quota and transmission line distance ratio is extensively investigated in this study. The results show that under the case of the wind, solar and hydropower ratio is 40:1:150, the optimal values for maximally reducing hydropower low frequency oscillation are finally determined as kp = 0.8, ki = 0.25 and kd = 0.5. Regarding a certain wind/solar/hydropower quota, it is a promising strategy to increase the solar-load transmission line in order to achieve the safe and stable operation of the hybrid system and a relatively excellent dynamic regulation capacity of the hydropower governor. The model, methods and results implemented in this study are exploited to markedly improve new knowledge applications, policy management, low carbon emissions and investment competitiveness of future energy systems.

Hydropeaking, a hydroelectricity generation strategy involving rapid changes to flow releases from dams in response to fluctuations in hourly-adjusted electricity markets, has been widely applied due to its economic efficiency. However, these operational practices produce sub-daily flow fluctuations that pose substantial hazards to riverine ecosystems and human activities. To ascertain the downstream impacts of hydropeaking, features of hydropeaking have been analyzed with respect to ecologically relevant hydrologic variables. However, since studies aiming to characterize hydropeaking regime often require manual feature extraction, they are limited to small temporal and spatial scales. Additionally, riverine ecologists have commonly treated hydropeaking as a broadly similar flow-alteration pattern regardless of the complexities of the electricity market and differences in the natural settings where it is applied. Therefore, this study sought to determine whether significantly different hydropeaking patterns exist on a regional scale, as revealed by the variation in hydropeaking over a long temporal scale (>five years). To fulfill this goal, a new algorithm, the Hydropeaking Event Detection Algorithm (HEDA), was developed in R to automate the characterization of hydropeaking flow regimes. Clustering analyses were conducted to explore the similarities and differences of hydropeaking regimes among 33 sites in numerous hydrologic regions of California. Four distinct classes of hydropeaking flow regimes were identified and distinguished by the duration and frequency of hydropeaking. Meanwhile, rate of change, amplitude and timing of hdyropeaking played less important roles in the classification.

Conflicts around the multi-purpose water uses of Lake Diefenbaker (LD) in Saskatchewan, Canada need to be addressed to meet rapidly expanding water demands in the arid Canadian prairie region. This study explores these conflicts to advance collaborative planning as a means for improving the current water governance and management of this lake. Qualitative methodology that employed a wide participatory approach was used to collect focus group data from 92 individuals, who formed a community of water users. Results indicate that the community of water users is unified in wanting to maintain water quality and quantity, preserving the lake’s aesthetics, and reducing water source vulnerability. Results also show these users are faced with water resource conflicts resulting from lack of coherence of regulatory instruments in the current governance regime, and acceptable management procedures of both consumptive and contemporary water uses that are interlinked in seven areas of: irrigation, industrial, and recreational water uses, reservoir water level for flood control and hydroelectricity production, wastewater and lagoon management, fish farm operations, and regional water development projects. As a means of advancing collaborative planning, improvements in water allocation and regulatory instruments could be made to dissipate consumptive use conflicts and fill the under-regulation void that exists for contemporary water uses. Additionally, a comprehensive LD water use master plan, as a shared vision to improve participation in governance, could be developed to direct the water uses that have emerged over time. This study suggests that these three areas are practical starting conditions that would enable successful collaborative planning for the seven areas of water uses. Focusing on these three areas would ensure the current and future needs of the community of water users are met, while avoiding reactive ways of solving water problems in the LD region, especially as the water crisis in the Canadian Prairie region where LD is located is expected to intensify.

The morphology of rivers and deltas, like many features of the Earth’s physical geography, is today subject to dramatic and rapid changes due to human actions. Deprived of sediment from their basins and besieged by rising sea levels, many deltas are at risk of complete disappearance. Despite a rich historical scholarship on rivers, we know little about the history of these important geomorphological processes. This paper sheds light on the geomorphological history of rivers by investigating the case of the Po River basin and its delta during the twentieth century. By combining the insights of fluvial geomorphology and a historical methodology, the paper analyses three main drivers of geomorphic alterations in the catchment that had an impact on the delta: hydroelectricity, sand and gravel mining, and methane extraction. In each case, it focuses on how experts, policy-makers, and overseers understood and regulated (or not) these geomorphic alterations. During much of the twentieth century, engineers and hydrologists monitored geomorphic processes with increasing detail, while state and business actors practiced multiple forms of sediment management. For most of the twentieth century, however, experts did not acknowledge the scale and nature of human-induced geomorphic alteration. Sediment management, moreover, did not take into account sediment scarcity until late in the century, and remained exclusively motivated by local concerns. Through this particular case, this paper offers insights on the historical limits to environmental expertise and policy when facing long term and large-scale geomorphic processes, and encourages a more sustained incorporation of fluvial geomorphology into the history of water systems.

While hydroelectric dams play a significant role in meeting the increasing energy demand worldwide, they pose a significant risk to riverine biodiversity and food security for millions of people that mainly depend upon floodplain fisheries. Dam structures could affect fish populations both directly and indirectly through loss of accessible spawning and rearing habitat, degradation of habitat quality (e.g., changes in temperature and discharge), and/or turbine injuries. However, our understandings of the impacts of dam life span and the initial fishery conditions on restoration time and hence the dynamic hydropower (energy)-fish (food) nexus remain limited. In this study, we explored the temporal energy-food tradeoffs associated with a hydroelectric dam located in the Penobscot River basin of the United States. We investigated the influence of dam life span, upstream passage rate, and downstream habitat area on the energy-food tradeoffs using a system dynamics model. Our results show that around 90% of fish biomass loss happen within 5 years of dam construction. Thereafter, fish decline slowly stabilizes and approaches the lowest value at around the 20th year after dam construction. Fish restoration period is highly sensitive even to a short period of blockage. The biomass of alewife spawners need 18 years to recover with only 1-year of blockage to the upstream critical habitats. Hydropower generation and loss of fish biomass present a two-segment linear relationship under changes in dam life span. When the dam life span is less than 5 years, generating 1 GWh energy cause around 0.04 million kg loss of fish biomass; otherwise, the loss of fish biomass is 0.02 million kg. The loss of fish biomass could be significantly decreased with minimal energy loss through increasing upstream passage rate and/or the size of downstream habitat area.

The Ethiopian government is undertaking the construction of Grand Ethiopian Renaissance Dam (GERD), the largest hydroelectric power plant in Africa with a storage volume corresponding to approximately 74 Billion Cubic Meters of water at the full supply level and is expected to produce 6000 MW power. The dam is located upstream of the Ethiopian–Sudan borders to utilize the water resources potential, and energy security to reduce poverty, but is controversially debated in the public and the scientific literature. The main objective of this research is to find out the extents of the long-term potential impact of the introduction of new upstream reservoir, GERD, on the downstream High Aswan Dam (HAD) of the Nile waters using the MODSIM simulation model. For model calibration and validation using the monthly flow data of 1956–2003, a good agreement was observed between simulated and gauged data at Dongola and Tamaniat stations. The correlation coefficient R2 values for those stations were found to be more than 0.92 for each station. Due to the presence of GERD, the energy production of Egypt from HAD will decline by 5.243%, but in contrast GERD will create additional energy of 15,000 GWh/year for the eastern Nile power grid system. The loss of water due to evaporation decreases significantly by 9.922%. This GERD will affect the inflow amount which is reached on Egypt by 2.755% and the reservoir storage elevation will not affect at much as expected (which fluctuates with range of 0.609%).

The Pettitt test is widely used in climate change and hydrological analyses. However, studies show difficulties of this test in detecting change points, especially in small samples. This st...

Plankton community samples from a reservoir were compared to samples from a river downstream of a large hydroelectric generating station on the lower Saint John River, New Brunswick, Canada...

We present an assessment of the potential impacts of climate change on hydropower production within a paradigmatic, very highly exploited cryospheric area of upper Valtellina valley in the Italian Alps. Based on dependable and unique hydrological measures from our high‐altitude hydrometric network Idrostelvio during 2006–2015, we set up the Poly‐Hydro model to mimic the cryospheric processes driving hydrological flow formation in this high‐altitude area. We then set up an optimization tool, which we call Poly‐Power, to maximize the revenue of the plant manager under given hydrological regimes, namely, by proper operation of the hydroelectric production scheme (reservoirs, pipelines, and power plants) of the area. We then pursue hydrological projections until 2100, feeding Poly‐Hydro with the downscaled outputs of three general circulation models from the Intergovernmental Panel on Climate Change Fifth Assessment Report, under the scenarios Representative Concentration Pathway (RCP) 2.6, RCP 4.5, and RCP 8.5. We assess hydrological flows in two reference decades, that is, at half century (2040–2049), and end of century (2090–2099). We then feed the so obtained hydrological scenarios as inputs to Poly‐Power, and we project future production of hydroelectric power, with and without reoperation of the system. The average annual stream flows for hydropower production decreases along the century under our scenarios (−21 to +7%, on average − 5% at half century; −17 to −2%, average − 8%, end of century), with ice cover melting unable to offset such decrease. Reduction in snowfall and increase in liquid rainfall are the main factors affecting the modified hydrological regime. Energy production (and revenues) at half century may increase under our scenarios (−9 to +15%, +3% on average). At the end of century in spite of a projected increase on average (−7 to +6%, +1% on average), under the warmest scenario RCP 8.5 decrease of energy production is consistently projected (−4% on average). Our results provide an array of potential scenarios of modified hydropower production under future climate change and may be used for brain storming of adaptation strategies.

Several researchers have extensively investigated the flow-induced vibrations caused by flood release because numerous structures have been destroyed by such release. Nevertheless, none of the previous research has considered vibration safety during flood control operation. In this study, a hedging scheduling model considering the near-field vibrations induced by flood release and hydrological uncertainty is proposed to optimize the discharge process. The dispatch model was applied to the Xiangjiaba reservoir due to the reservoir’s classic problem of near-field vibrations induced by flood release. The measured root-mean square (RMS) data for the acceleration in the vertical direction of near-field vibrations were used to summarize safety constraints. The vibration safety discharge ceiling was determined according to field test records and was regarded as an operational safety constraint for the dispatch model. Based on this innovative safety constraint, this paper demonstrates the development of an optimal dispatch model for reservoirs by considering forecast uncertainty. The proposed strategy utilizes storage capacity to optimally allocate the gap between the expected flood volume and vibration safety discharge capacity (GBEV) in the discharge process. Optimal flood control operation considering the near-field vibrations induced by flood release falls into four categories, with each category corresponding to one optimal operation strategy. The solution set to this model can provide decision support for reservoirs with similar flood-induced vibration problems and optimize the power output of hydropower stations.

Water resources can play significant roles in development pathways for water-endowed, low-income countries like Nepal. This article describes three visions for water resource development in...

Hasanlar Dam and Hydroelectric Power Plant are located on Kucuk Melen Creek in the Western Black Sea Basin of Turkey. The dam was constructed in 1974 to provide domestic water needs of the Duzce Province, to supply irrigation water need, to control and mitigate floods and to produce hydroelectric power. This dam has been subjected to severe sedimentation since its construction in 1974. Therefore, bathymetric field survey studies were conducted to determine storage loss in the Hasanlar Dam reservoir by sedimentation. Bathymetric survey data from the reservoir site of the Hasanlar Dam were obtained in 1979, 1999 and 2014. Analysis of the bathymetric data, GIS and remotes sensing techniques showed that storage loss in reservoir active volume between 1974 and 1999 was 24% and between 1974 and 2014 storage loss was 26%. Analysis of the bathymetric maps also showed that sediment accumulation is severe near and around the dam body and the spillway whose discharge capacity was decreased by sediment accumulation. This is extremely critical because the flood of May 1998 caused the high risk of collapse of dam due to reduced capacity of the spillway. Remote sensing technique was used to determine the future deposition of sediment in the reservoir. For this purpose, 35 points in the reservoir area were determined by comparing the relative water depths and actual water depths using satellite image of the bathymetry in July 2017 and Lake Observation Station. High correlation (R2 = 0.833) was calculated by using logarithmic nonlinear regression analysis between actual and relative water depths for those 35 control points. The average of absolute values of differences between the estimated and actual water depths was found as 1.06 m, and RMSE was calculated as 1.25 m. This analysis shows that in the future, remote sensing data can be used in the studies of determining the depth of water and the total sediment thickness. In addition, the volume of the entire reservoir can be predicted by measuring the actual water depth only at those 35 control points without making a bathymetric map of the whole dam reservoir.

Water resources optimal allocation in large complex water systems such as multi-reservoir dams is a challenging task for decision makers. Wide range of decision variables as well as difficult nonlinear optimization problems (highly nonlinear problems) make it difficult to use optimization approaches. Alternatively, simulation–optimization approaches are then providing more realistic and applicable solution. This study presents a simulation–optimization framework for extracting monthly long-term operation rules. This method is applied to Karun River Basin including six multi-objective (hydropower generation, agricultural and environmental water supplement) cascade dams. In this regard, Water Evaluation and Planning System is used as the simulation model coupled with an optimization model. Decision variables include (1) monthly variation of top of buffer parameter in reservoirs where the reservoir releases water to meet the required demand and (2) monthly priority for filling of the reservoirs. Two-objective NSGA-II algorithms are used to minimize sum of squares unmet energy and agricultural water demands within two scenarios. The results show that the reliability of the generation of hydroelectricity in Karun River Basin has been increased sufficiently. Results showed that the scenario 2 (an aggregate energy demand at the system level) has better performance in terms of reliability (91.4% compared to 89.6%) and efficiency of centralized approach in which all reservoirs are operated in an integrated management scheme.

Recent major droughts in Brazil have given rise to discussions about water availability and security in relation to energy production. The relationship of the two resources, the water-energy nexus, is recognised as being of importance in literature and metrics for its estimation and understanding are sought after. One important aspect in understanding the water-energy nexus of hydroelectricity is estimating its water consumption and also its water footprint. In order to do this, this study uses a modified Penman-Monteith method to estimate evaporation from Brazil’s reservoirs for the period 2010-2016 and subsequently calculates the water footprint of hydroelectricity reservoirs. The results show the evaporation variation in space and time in the reservoirs and the differences of water consumed per unit of energy in Brazil. The discussion provides insight as to how the results can be valuable for future management and planning purposes.

The concept of sustainable development is gaining popularity and hydroelectric projects designed and operated on this concept require sediment management as prime design criteria. Drawdown ...

Three hydroelectric reservoirs (Kralkizi, Dicle and Batman) in the Tigris River basin (Turkey) were sampled monthly during one year in order to reveal spatial and seasonal changes in aqueous partial pressure of CO2 (pCO2) and to estimate diffusive fluxes of CO2 from the reservoirs’ surface water. pCO2 concentrations did not show significant spatial differences, while they showed significant seasonal variations. Temperature, precipitation and biological CO2 uptake through photosynthesis controlled pCO2 seasonality in the reservoirs, with maximal concentrations in the winter (ranging from 516.9 µatm in Kralkizi to 1299.2 µatm in Dicle) and minimal concentrations in the spring (ranging from 47.7 µatm in Batman to 140.7 µatm in Kralkizi). Most studies reported that reservoirs worldwide are net sources of CO2 to the atmosphere. However, the reservoirs in this study were sinks for atmospheric CO2 during the spring, summer and autumn seasons, while they were CO2 sources to the atmosphere during the winter. Air-water CO2 fluxes in Kralkizi, Dicle and Batman dam reservoirs were 2.39, 32.88 and 8.12 mmol/m2/day in the winter, respectively. On an annual basis, all three reservoirs acted as a sink for atmospheric CO2. These estimated CO2 fluxes were in the lower range for temperate reservoirs, despite the potential for winter conditions that shifted the reservoirs from sink to net source for atmospheric CO2.

Despite public awareness of unintended impacts (1980s) and well-developed international standards (2000s), downstream impacts of large hydropower projects still very often are not properly assessed. Impacts of (hydropower-regulated) interbasin water transfers (IBWTs) are considered self-evidently positive, although they can have far-reaching consequences for hydrogeomorphological systems and consequently river-dependent communities. In this study, the downstream direct and indirect impacts of the Ethiopian hydropower-regulated Tana-Beles IBWT are evaluated in an interdisciplinary way. The components of the framework of rural livelihoods are considered and changing contexts, resources’ availabilities and livelihood strategies are analysed. Mixed methods are applied, combining hydrogeomorphological field observations, GIS analyses, scientific literature, policy documents, and semi-structured interviews with local people and local to federal authorities. Results show that the IBWT drastically increased the Beles river’s discharge (with an average release of +92 m3 s−1 at the outlet; *2 in rainy season and *12 in dry season 100 km downstream of the water release) and introduced dangerous situations for local communities (over 250 people drowned in the river). River bank erosion resulted in the uncompensated loss of farmland (163 ha) and the establishment of large-scale commercial farms increased the pressure on land and led to the impoverishment of displaced communities (4310 households). The project was implemented top-down, without any transparency, benefit sharing or compensation for external costs. This stresses the importance of downstream interdisciplinary impact assessments and highlights the need for decent in-depth ex post-analyses of hydropower projects. Environmental impact assessments should be taken seriously and cannot be considered a formality. In Ethiopia and in many developing countries, the hydropower industry is booming. Although dams and IBWTs can be the best solution for water-related problems in specific contexts, national development goals (such as the expansion of the electricity network) should not be at the expense of rural livelihoods.

Longitudinal connectivity is one of the prime issues addressed in river restoration our days. At the same time, mitigation of climate change impacts by modes of renewable energy increasingly puts pressure on the remaining free flowing river stretches for hydroelectricity production. At the site level, this trade‐off manifests in the negotiation of water for upstream and downstream fish passage versus losses for hydroelectricity production. This study has compiled and analysed 193 studies evaluating fish passes designed to provide upstream migration for all species and size classes of the respective river system. The overall assessment of functioning and discharge dedicated to fish pass maintenance, site, and river characters were provided by the studies. The main objective here was deriving general guidance for the minimum amount of water needed for fully functioning upstream fish passage in relation to river size. There was a significant correlation between functionality and design discharge of a fish pass. Fully functioning fish passes (N = 92) had median design discharge of 5% of the mean average discharge of the river, restrictedly functioning of 1.1% and not functioning of 0.22%. A power model could be derived of design discharge needs in relation to river discharge, which is inversely related to river size. In large rivers, a rather small share of mean discharge is sufficient, whereas in small rivers, it cannot be further downscaled due to dimensions. This model might provide first guidance in adjusting needs for both hydroelectricity generation and fish conservation in regulated rivers.

Erosion on reservoir margins causes losses in the production of energy in Hydroelectric Power Plants (HPPs), making it necessary to implement control techniques that ensure the reduction in sediment deposits inside reservoirs. Among these techniques, geomats (geosynthetic erosion mats) are widely used to control erosion processes in slopes and watercourses. This material protects the margins both in the short and long term, contributing to strengthening the vegetation’s roots developed in the erosion areas. This paper studies the performance of geomats (with and without sack gabion) installed in six margin sections distributed in three experimental units of the Brazilian HPPs called Porto Colômbia and Volta Grande. The geomat performance was evaluated over four years of monitoring through a qualitative evaluation matrix and differential bathymetry. The influence of ultraviolet (UV) radiation on the degradation of geomats installed in each section (natural conditions), as well as on geomat ultraviolet-aging samples in the laboratory (accelerated conditions), was also evaluated using differential scanning calorimetry (DSC). The results showed no significant difference in performance between using the erosion control technique consisting only of geomats and the technique consisting of geomats and sack gabion. The highest bathymetric difference value obtained in the present study was 1.62 m in the experimental unit VG1, controlled with geomat without the application of sack gabion on the margin.