Hydroelectric dams

The slogan "Water is Life" rallies anti-extractive movements across the Americas. Critical theorists, however, decry the circumscription of environmental politics by the vitalist attribution of political agency to liveliness. This article tempers that critique by juxtaposing it to the Catholic Church's claims to sovereignty over life, deploying the resulting slippages between water and life to explore the theopolitical potencies that emerge in water's oscillations between non-life and the divine. Exploring these oscillations in a dam conflict in Chilean Patagonia, I argue that they allowed a flooding phenomenon on a river threatened with damming to be heard as a prophetic call to action. The uprising that followed produced a rare victory for dam opponents, suggesting that a theopolitics of life has powers that exceed vitalism.

Transboundary hydropower dams are sources of hydroelectricity supply that sit in shared international rivers or watersheds, and/or generate benefits and costs that flow across national borders. Scholars have been exploring the impacts of hydropower dams at a local, regional and national scale for decades, however the transboundary impacts of hydropower ventures have been less studied. Nonetheless, the advent of a new hydropower boom, where a large proportion of untapped hydropower potential lies in transboundary settings, means that there is a need to better understand the specific benefits and costs in those contexts to foster more equitable and just outcomes, and to better examine the dynamics shaping the future of hydroelectricity. To depict the state-of-the-art within this critical field of research, we conduct a systematic review of 1264 peer-reviewed articles published on transboundary hydropower dams from 2009 to 2019. We find that most studies in our sample focus on issues related to water management and water allocation, whereas fewer focus on the scope of hydropower benefits, their temporal and spatial variation, and equity and justice dimensions. Moreover, there is minimal exploration of how differences in relative economic and financial capabilities can impact the distribution of transboundary hydropower benefits. Whether transboundary hydropower dams lead to optimal outcomes is highly dependent on underlying benefit sharing arrangements as well as an explicit acknowledgement and tackling of governance asymmetries. The study concludes that there is an urgent need to systematically assess these conditions to favour just outcomes for all stakeholders.

Rapid expansion of hydropower dams threatens many of the remaining free-flowing rivers in the biodiverse tropical regions of the world, interrupting the migrations of freshwater fishes on which millions of people rely directly for their livelihoods 1-3. As a consequence, there is a growing need to carefully balance the trade-offs between hydropower production and ecosystem functioning to avoid biodiversity losses and ensure long-term food security and income 3,4. Considerable scientific activity and international scrutiny remain focused on LHPs, whereas the environmental repercussions of smaller projects have been largely overlooked in broad-scale energy policies and garner little public attention. Despite (and perhaps due to) this oversight, a series of political and economic incentives for renewable energies have been implemented across the world to benefit projects that are labelled as SHPs-which are often defined as plants with a generation capacity of less than 10 MW-but this threshold may vary among countries 5. These incentives assume that, in addition to the lower energy generation capacity of SHPs, 'small' also equates to low environmental impacts. This has ultimately led to licensing exemptions, favoured energy prices (for example, feed-in tariffs) and subsidized loans that fuel increased construction 5-8. However, emerging scientific evidence suggests that the ecological impacts of SHPs can be dispro-portionally high for their societal benefits 9,10. The primary concern with rapid SHP development is that their number dwarfs that of LHPs. Today, more than 80,000 SHPs are operating in at least 150 countries (11 times the number of LHPs) and the construction of tens of thousands of new dams is projected 5. Despite being widespread, the aggregate contributions of SHPs to electrical grids are often quite low. For example, according to Brazilian regulations, SHPs are defined as those with a generation capacity below 30 MW. Although they represent more than 85% of the 1,517 hydropower plants operating in the country, they are responsible for only 7% of total generation capacity 11. The imbalance between the number of power plants and their generation capacity calls into question whether the marginal contributions by SHPs to national-level energy requirements are worth their potential environmental and societal costs. The cumulative impacts of SHPs on basin-wide hydrology and habitat connectivity may exceed that of LHPs when standardized by hydropower generation 9,10 , therefore challenging the majority of environmental policies that focus on the impacts of individual, and often large, dams 5,12. Owing to their sheer number and geographical extent, the widespread proliferation of SHPs may be an important, yet underappre-ciated, threat to the persistence of migratory fishes and the fisheries and diverse societal values that they support 3,13. Dams constrain the movement of migratory fish along river networks and isolate critical habitats that are necessary for their life history (for example, spawning and feeding grounds), resulting in local extinctions, population declines and collapses of fishery stocks 14-16. As a consequence, migratory fish species are among the most vulnerable organisms to hydropower development in the tropics 17 , which is concerning considering their high ecological and socioeconomic importance. For example, migratory species have key roles in food webs and ecosystem functioning 18,19 , and are included among the top-ranked inland fisheries on the basis of market values and cultural preferences 15,20. Past and planned dam construction greatly exacerbates the loss and fragmentation of habitat in dendritic river networks through the cumulative effects of multiple barriers 21,22 and therefore threatens the persistence of migratory fish and the resilience of fisheries 23. Optimal siting of new dam construction is paramount when attempting to balance the trade-offs between hydropower generation and the river fragmentation that threatens migratory fish 24 , yet it is noticeably absent from many national energy plans. Managers and decision makers have a wide range of options to help to guide the location on the landscape at which prospective hydropower projects may be constructed 25. Recent attention has focused on the use of trade-off assessments of multiple objectives to identify win-win management opportunities and provide more prescriptive recommendations , which are both highly desirable in decision-making 26. Small hydropower plants (SHPs) are proliferating globally, but their cumulative threat to blocking migratory fish and the fisheries that these fish sustain has been underappreciated when compared with large hydropower plants (LHPs). Here, we quantified the trade-offs between hydroelectric generation capacity and the impacts on river connectivity for thousands of current and projected future dams across Brazil. SHPs are the main source of river fragmentation, resulting in average connectivity losses of fourfold greater than LHPs. Fragmentation by SHPs is projected to increase by 21% in the future, and two-thirds of the 191 migratory species assessed occupy basins that will experience greater connectivity losses due to SHPs than LHPs. A Pareto frontier analysis identified future dam portfolios that could halve the number of hydropower plants that are required to deliver the same energy-generation capacity compared with the least-favourable solutions, while simultaneously resulting in lower river fragmentation and protecting numerous undammed basins. Our results highlight the need for strategic planning that considers the unprecedented growth and cumulative effects of SHPs.

The Mekong River, well known for its aquatic biodiversity, is important to the social, physical, and economic health of millions living in China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. This paper explores the social and environmental impacts of several Mekong basin hydropower dams and groupings of dams and the geographies of their impacts. Specifically, we examined the 3S (Sesan, Sekong Srepok) river system in northeastern Cambodia, the Central Highlands of Vietnam, and southern Laos; the Khone Falls area in southern Laos; the lower Mun River Basin in northeastern Thailand; and the upper Mekong River in Yunnan Province, China, northeastern Myanmar, northern Laos, and northern Thailand. Evidence shows that these dams and groupings
of dams are affecting fish migrations, river hydrology, and sediment transfers. Such changes are negatively impacting riparian communities up to 1000 km away. Because many communities depend on the river and its resources for their food and livelihood, changes to the river have impacted, and will continue to negatively impact, food and economic security. While social and environmental impact assessments have been carried out for these projects, greater consideration of the scale and cumulative impacts of dams is necessary.

This paper examines the relationship between built infrastructure, space, place, and mobility within the context of India's prolonged occupation of Kashmir. Using the example of the 330 MW Kishanganga dam, built on the transboundary Kishanganga River, I argue that the dam was an outcome of India and Pakistan's territorial contestations over Kashmir as well as India's attempt to assert greater control over Kashmir's strategic resources. While India used the rhetoric of integration to normalize its extractive interventions in Kashmir, the dam imposed new and systemic constraints on people's movements along the LoC. Foregrounding people's resistance practices, the paper examines the intersections between regimes of immobility and India's extractive politics of integration in Kashmir.

Plans are underway to construct twelve large hydropower projects on the
un-dammed lower and middle mainstream Mekong River in Laos, Thailand, and
Cambodia. One of the planned projects is a 30–32 meter–high hydroelectric dam
with an expected 240 MW installed generating capacity to be built on the Hou
Sahong Channel, less than one kilometer north of the Laos–Cambodia border, in
the Khone Falls area of Khong District, Champasak Province, southern Laos. The
project’s objective is to generate revenue by exporting electricity to Thailand or
Cambodia. Concerns have been raised about the Don SahongDam(DSD), however.
The main ones relate to potential repercussions on aquatic resources, and especially
wild-capture fisheries dependent on migratory fish. This article examines the
regional implications of the DSD, including possible impacts on food security, nutrition, and poverty alleviation. Fisheries losses in the Mekong Region from the DSD
would negatively affect the nutrition of hundreds of thousands or even millions of
people, especially in parts of Laos, Cambodia, and Thailand where nutritional standards are already low. Mekong fisheries are integral to food security in the region,
and the DSD would make it difficult for governments, especially in Laos and Cambodia, to reach their health-related United Nations Millennium Development Goals
and their objectives for reducing poverty.

Designing concrete based on aggregate packing and optimized gradations can result in 25 % less cement content to reach a targeted compressive strength and less water-reducing admixture to obtain a required consistency. In this research, two studies were conducted: (1) an experimental analysis to determine the effects of aggregate packing on concrete strength and consistency; and (2) an investigation of the relationship between the traditional dry-rodded and the vibrated aggregate packing. Excellent correlation was found between 240 packing results, which can be applied to the modified mixture design method presented. Also, 40 slump and 120 compressive strength standard tests were performed to evaluate the effects of reducing cement content by 7.5, 15, 20, and 25 % to slump and compressive strength of concrete mixtures. The compressive strength of the optimized mixture demonstrated less susceptibility to variations due to cement content reductions when compared to nonoptimized mixtures. The Modified Coarse Factor Chart can be used to design an optimized concrete mixture efficiently in conjunction with aggregate gradation and packing, cement content, and concrete consistency.

In this work we study long-term maximization of hydroelectric energy generation from complex multipurpose reservoir systems, using the reservoir system of the Aliakmon River, Greece, as an application example. This system serves various purposes, like urban water supply, irrigation, hydroelectric energy production, cooling thermoelectric power plants and flood control, while preserving environmental flow. The system operator uses institutional rules for the annual scheduling of the outflows of the 2 largest reservoirs (Ilarion and Polyfyto) for additional safety and smooth distribution of energy production through the year. In this work, we focus on maximization of energy production. We have considered three different hydrological scenarios (dry, average and wet), both for the current and for anticipated future water demand. The multi-reservoir system's operation was simulated and then optimized using a rather simple form of genetic algorithms, in order to maximize hydro energy production. All other water uses were taken into account as constraints. Our conceptual and computational approach succeeded to identify and quantify hydro energy production increase and to indicate necessary changes to the operating rule curves of the reservoirs. The methodology can be easily adapted to other large-scale multi reservoir systems.

Resumo: A barragem hidrelétrica de Tucuruí foi construída nas margens do rio Tocantins, no Pará, entre 1974 e 1984. Este artigo trata da implantação de uma verdadeira sociedade da barragem através da instalação de uma cidade-empresa para abrigar os diversos trabalhadores e trabalhadoras implicados nessa construção. Aqui, partiremos da lógica empresarial e institucional para tratar da implantação, organização e funcionamento desse espaço particular, tentando por um lado caracterizar quem são as pessoas que participam da construção dessa barragem e refletir sobre a maneira como esse tipo de espaço controlado por uma empresa participa da disciplina dos corpos e da vida dos trabalhadores dentro e fora do canteiro, visando à maximização da produtividade. Como espaço de controle, inevitavelmente há reações que também farão parte desta análise. Esta pesquisa segue o curso das fontes institucionais e técnicas da construção de barragens para tentar caracterizar a implantação e a gestão de um canteiro de obras durante a ditadura militar.

 Brazil’s President Jair Bolsonaro has announced his administration’s priorities for
Amazon dams, including the planned Bem Querer dam on the Rio Branco in the farnorthern
state of Roraima.
 Bem Querer is primarily intended to increase the energy supply to industries in
locations outside of Amazonia, rather than for residents of Roraima.
 Probable environmental impacts include blocking fish migrations and flooding a
riparian forest that possesses extraordinary bird diversity. Downstream flow alteration
would impact protected areas, including two Ramsar wetland biodiversity sites.
Riverside dwellers would also be impacted.
 Sediment flow blockage would impact fisheries and the unique Anavilhanas
Archipelago, a spectacular Brazilian national park. These adverse impacts need to be
fully evaluated before a decision to build is made.

 O atual Plano Decenal de Expansão de Energia do Brasil prevê a
construção de mais três grandes usinas hidrelétricas na Amazônia até 2029 e
o Plano Nacional de Energia 2050 inclui várias outras.
 Ambos os planos contêm trechos preocupantes que indicam um aumento na
lista de hidrelétricas se for resolvida a “incerteza” com relação à atual
legislação sobre povos indígenas e áreas protegidas.
 O Congresso Nacional está examinando projetos de lei que eliminam o
licenciamento ambiental: uma proposta apresentada pelo presidente Jair
Bolsonaro permitiria hidrelétricas em terras indígenas.
 Os planos do Brasil para construir usinas que atendam à demanda de
energia de 2050 se estendem às nações amazônicas vizinhas, incluindo Peru
e Bolívia.

A Amazônia já tem mais de uma dúzia de grandes hidrelétricas, e a história não é boa, com severos impactos humanos e ambientais e com benefícios muito aquém dos que foram imaginados pelos proponentes na hora das decisões [1]. As lições desta história não foram aprendidas, e hoje o governo avança rapidamente nos seus preparativos para mais uma barragem com sérios questionamentos-a Usina Hidrelétrica (UHE) Bem