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The present paper aims to evaluate the empirical as well as analytical approaches normally adopted for the computation of desilting efficiency of pressure type desilting basin used in hydroelectric project (H.E.P) constructed in Himalayan regions. Due to limited availability of space and steep topography, pressure type desilting basins are mostly preferred. Four significant projects in the Himalayan region are chosen for the performance analysis of desilting chamber: Kholongchhu H.E.P, Mangdechhu H.E.P, Teesta Stage-IV H.E.P, and Punatsangchhu Stage-II. Theoretical efficiency (function of shear velocity (µ*) and mixing coefficient (ℇ)) of all the four projects were computed by existing as well as modified formulae as suggested by Camp-Dobbin (1946) and Sinha and Singh (2019), respectively. It is concluded that particle removal efficiency obtained from model studies for these four hydropower projects and that computed by Camp-Dobbin's approach (1946) are in close agreement. The outcome of this paper suggests that out of six commonly used approaches, the approach recommended by Camp-Dobbin (1946) is most suitable methodology to design the desilting basin in Himalayan region. It is envisaged that the present study will enable the designer to select a most appropriate approach to design an efficient and suitable desilting basin for construction in Himalayan region. [ABSTRACT FROM AUTHOR]

Building flood reduction dams for territory protection is very often necessary as it allows the reduction of peak flows during flood events by creating a storage in upstream areas. An online structure with such characteristics is outlined, presenting one or more openings in order to allow normal and moderate flows to pass downstream. A stilling basin is provided downstream of the openings and, on one side of the flooded area, a spillway weir is set. For low river flows, the openings will act as free-surface weirs. The openings are equipped with a sill in such a way to let the discharge independent of the downstream flow conditions. For moderate flood flows, the water level upstream of the dam will rise, and the openings will become submerged, effectively behaving as an orifice arrangement. For large flood flows, the crest of the flood spillway weir is reached and they will be discharged via both the orifice structure and the flood spillway structure. The silled openings and the stilling basin are one only hydraulic complex. Since no examples exist of their behavior as a whole, the aim of this paper is to give the designers the opportunity to size them given the basic requirement of the flood reduction dam, i.e. the max discharge allowed downstream. For this reason, the paper will focus on the opening discharge coefficients, the stilling basin energy dissipation and water level. Both the orifices and the stilling basins were studied starting from the hydraulic models of three dams that were built in Calabria (Italy). The structures of the stilling basins are original. The results appear in dimensionless form and offer useful guidance for similar hydraulic cases, with the exception of specific terrain related issues. Finally, an example of a preliminary design of orifices and stilling basin is presented. [ABSTRACT FROM AUTHOR]

While the benefits of mega-dams are irrefutable, the destruction they entail necessitates critical attention. This paper engages with alternative histories on Kariba Dam to index the precarization of indigenous people and the degradation of the environment. I make the claim that the rhetoric and architecture of hydro-modernity drowns the brutal violence that subtends it. The paper pursues a close hydro-critical reading of three selected texts on Kariba Dam: Frank Clements' Kariba: The Struggle with the River God (1959), David Howarth's The Shadow of the Dam (1961) and Bob Nyanja's film Nyaminyami: The River God (2018). Although the selected works are largely binary and are informed by colonial schemas, my watery analysis aims to lay bare these structures and highlight the points at which these binaries become unsustainable. I draw on Isabel Hofmeyr, Sarah Nuttall and Charne Lavery's lens of the hydro-infrastructural (2022), Hofmeyr's concept of hydrocolonialism (2022) and Rob Nixon's notion of slow violence (2011) as a combination of theories that offer ways to think about water infrastructures and hydrological themes from an ecological and postcolonial perspective. [ABSTRACT FROM AUTHOR]

Balancing between sediment removal discharge and dam reservoir storage loss considering river environmental impact is of major and practical concern. The paper presents indices for evaluating the sediment removal performance of a Vertical Multi-hole Hydrosuction System (VMHS) in view of environmental impacts. A new hole arrangement on the vertical pipe of VMHS was experimentally examined. The compiled data of the temporal variations of the sediment concentration and the cumulative volume of removed sediment demonstrated that the arrangement of the holes on the vertical pipe of VMHS has profound impact on the speed of sediment removal and on the reservoir water loss. The high concentration of the outflow from the reservoir, however, might affect the downstream water course environment. The proposed indices could be applied to determine the proper duration for terminating the hydrosuction process in order to obtain a balance between the storage capacity and the downstream water course environment. [ABSTRACT FROM AUTHOR]

What if cycling infrastructure such as nationwide bikeways becomes part of an engineering project that is an antithesis of sustainability? How do cyclists reconcile between their pride in cycling as a healthy way of appreciating nature and the environmental destruction observed along their cycling paths? This paper complicates the familiar characterization of cycling as easily compatible with sustainability agenda by examining South Korean cyclists' response to the construction of the Four Rivers Bikeway. The Bikeway was planned as a part of the Four Rivers Restoration Project, the largest and most controversial environmental engineering work in the nation's history. Whereas environmental groups, academics, and concerned citizens strongly opposed the so-called restoration project for its potentially devastating impact on the rivers' ecosystem, many cyclists welcomed and then enjoyed the nationwide network of cycling paths built along the rivers. In doing so, the cyclists came to consider the new bicycle haven as a space insulated from broader environmental politics within which their riding was made possible. The healthy, nature-loving cyclists on the Four Rivers Bikeway manifested a peculiar kind of "cycling citizenship" – "the links people make between cycling and the worlds outside the bicycle" – that endorsed the state's investment in cycling infrastructure while evading the question of the state's responsibility for environmental destruction. This paper suggests that the future sustainability of cycling may not be considered separately from the broader concerns for environmental sustainability and the inevitable political debates around it. [ABSTRACT FROM AUTHOR]

The developmental projects like dams and other capitalist structures in India, allocate the natural water reserves to elite industrialists and state apparatuses, leaving the local ecosystems impoverished and in the hands of capitalism driven policies, which milk the indigenous population to mollify the materialistic needs of the affluent. This predicament is vividly illustrated in Subhash Vyam's graphic narrative Water that employs the traditional Gond Art to anchor the consequences of the 'Slow Violence' rendered to the local ecosystems owing to the development policies. As the revered natural sources of water in Vyam's village are regulated through a dam, the rural Indigenous community is deprived of its basic rights to survive, vandalising the pious 'human-water' relationship, resulting in 'a serious ecological crisis'. Drawing theoretical insights from Rob Nixon, Ramachandra Guha and Vandana Shiva, the proposed paper attempts to emphasize that the graphic narrative Water, through its remarkable graphic visuals, conjoined with local customs and folklores, is a reflection of the agony of the indigenous communities. Further, the paper analyses the grim reality that privatisation not only leads to exploitation and consequent depletion of the natural resources, but also robs the local communities of their ways of survival and resource sharing practices. [ABSTRACT FROM AUTHOR]

The present paper evaluates the impact of stress history on yielding, shear and energy dissipation response of earthen dam soil under static and cyclic loading conditions by conducting consolidated undrained (CU) triaxial tests and cyclic simple shear (CSS) tests respectively. The current research has been performed at four different stress histories (over consolidation ratio = 1, 2, 5, 10) on loose, medium and very-dense specimens under static and cyclic loading conditions. The generation of stress history enhanced the soil particle interlocking and stability of the soil structure resulting in substantial improvement in the undrained static and cyclic strength of the soil. Loose and medium-dense specimens' shear response exhibited metastable structure formation; conversely, the very-dense specimens revealed more stable structural adjustments. The 'teardrop' shaped yield surface grew substantially as the density state changed from loose to medium-dense to very-dense. The incremental strain vectors at pre and post-instability states indicated highly compressive behaviour in loose and medium-dense specimens. The undrained static and cyclic shear behaviours were analysed in the context of energy dissipation under different stress histories. All soil specimens (loose to very dense) exhibited liquefaction susceptibility under cyclic loading conditions at all stress histories. [ABSTRACT FROM AUTHOR]

This paper analyzes agricultural pathways and the impacts of land requisition from dam construction in a Catholic community in Tibetan Southwest China. Cizhong Village is unique for its Catholic religion and unique agroecology of growing paddy rice and grapes for household winemaking, one of the very few ethnic Tibetan communities to do so. This unique agriculture is due to the community being located at the boundary between two larger culinary/agricultural spheres, rice boiling, and wheat grinding peoples. The situation has changed with a construction of a large dam, which caused another community to be moved on top of the village's paddy fields. In the context of this issue on food politics, the paper also highlights the ways in which new global forces related to infrastructure (dam building), are disabling unique interfacing forms of self-sufficient food production, leading to emotional responses among rural farming communities. [ABSTRACT FROM AUTHOR]

The Andes, located along South America's western side, is among the world's longest mountain ranges and is one of the most intense seismic activity areas caused by the Pacific Oceanic plate sliding under the South American continent, mainly when the range passes through Peru and Chile, covering an area of 3.37 million km2. The Himalayas mountain range is among the most seismically active regions in the world, mainly when the range passes through Nepal, China, India and Pakistan, due to the collision between the Indian and the Eurasian continental plates, covering an area of 1.09 million km2. Eastern Anatolia mountain range of Turkey covering an area of 0.15 million km2 is also one of the most seismically and tectonically active regions due to the frequent occurrence of earthquakes. These three areas and other few in the vicinity of high seismicity were considered for this paper based on in situ working experience for several dam spillways and large dams with heights up to 335 m. Of these 50% under operation, 25% under construction and 25% under final design stages. The earthquake safety of dams is an important topic in dam engineering and dam safety, and the seismic behavior of dams subjected to severe earthquakes and mainly their consequences downstream must be very well defined providing the adequate seismic factors not only from the engineering point of view but also thinking on damage risks, for a proper application. This paper evaluates the main concept of seismic hazard analysis and the PGA value defined for these dams in the Andean, Himalayas and Eastern Anatolia mountain ranges for the MDE, SEE and OBE earthquakes and their implications for the dynamic and static analysis. [ABSTRACT FROM AUTHOR]

The Grand Ethiopian Renaissance Dam (GERD) has created disputes between the Nile River's lower and upper riparian zones in North Africa. Ethiopia sees the GERD as a project to prosper, while Egypt considers that it will imperil the country's economy. After the African Union (AU) failed to resolve the disputes over GERD, the matter reached to the United Nations Security Council (UNSC) which, after discussions, stated that the matter should be resolved at the regional level. This paper examines the theoretical and conceptual aspects of transboundary river waters and why riparian states shy away from cooperative arrangements. The paper then discusses the history of water disputes in the Nile Basin region and analyses the history of water distribution and projects in North and eastern Africa. Finally, the paper analyses the role of other countries, the AU, and the UNSC in disputes over the GERD project. [ABSTRACT FROM AUTHOR]

The problem of steady-state seepage flow underneath diversion dams on permeable soil of infinite depth with a cutoff wall at the downstream end with a certain width has not been previously solved. This paper uses conformal mapping and the Darcy equation-based approach to investigate the exact solution. Closed-form analytical equations are given for changes in hydraulic gradient, seepage discharge, and uplift pressure. The results are easily used to create design diagrams. These diagrams show that along the specified length of the structure, with increasing cutoff wall width, hydraulic gradient and seepage discharge decrease, and the pressure difference between the two endpoints of the cutoff wall increases. Also, increasing cutoff wall width has a more negligible effect on reducing hydraulic gradient and seepage discharge at large-length structures. In addition, at greater distances from the downstream end of the structure, the effect of the width on hydraulic gradient reduction and seepage discharge is minimal. [ABSTRACT FROM AUTHOR]

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In this paper, we consider the estimation of a multicomponent stress–strength reliability when stress and strength variables follow unit Bur XII distribution. In estimation procedure, the maximum likelihood and Bayesian methods are used. The maximum likelihood estimator is obtained via iterative methods. The asymptotic confidence interval is constructed using asymptotic properties of the corresponding estimator. In addition, two bootstrap confidence intervals are constructed. Bayesian estimator is obtained using three different approximation methods: Lindley's approximation, Tierney–Kadane approximation and Markov Chain Monte Carlo method. The interval estimation based on Bayesian method is studied. The simulation study is conducted to investigate and compare the performance of the considered methods. Finally, an original data set, general dam occupancy rate of Istanbul, Turkey obtained from Istanbul Statistic Office, is analysed in the concept of multicomponent stress–strength reliability. [ABSTRACT FROM AUTHOR]

Because of the complexity of the dam failure mechanism due to earthquakes that occur under the simultaneous influence of hydraulic and seismic forces, a single model has not been obtained so far and this study was conducted to achieve this model. In this paper, dam failure models including both sudden and gradual failure have been investigated using volume of fluid techniques (VOF) to simulate water fluxes, general moving object (GMO) to simulate moving bodies, and the fluid–structure interaction model for finite volume analysis. In order to be sure of the accuracy of the results, before examining the failure mechanisms, the verifications of utilized methods in the case of dam failure were proven using experimental and numerical studies from literature. The Koyna Dam earthquake of magnitude 6.5 (11 December 1967) is investigated as a test case. Comparison of the output discharges due to dam failure in the two failure models reveals that the peak discharge of sudden failure is recorded three times faster than the gradual failure mode. Another achievement that should be mentioned is that although large oscillating periods carry a higher risk of cracking of the dam's body, smaller periods propagate the resulting cracks more rapidly. [ABSTRACT FROM AUTHOR]

This study examines news coverage of a federal project that resulted in the building of Glen Canyon Dam on the Colorado River and sparked an environmental controversy. The project pitted boosters against conservationists, and this research illustrates how western newspapers promoted growth through dams and irrigation. Acknowledging the region in which several newspapers operated, this study uses New Western History to better understand journalism history by highlighting the harsh landscape and the persistence of pioneer values in the 1950s. This research also introduces a new element of environmental journalism history by adding to understanding of such reporting in the 1950s and by approaching the dam controversy from the perspective of journalism rather than environmentalism. Whether newspapers focused on growth and prosperity or preserving natural beauty, their coverage reflected the complexity of the region and its ecosystem. [ABSTRACT FROM AUTHOR]

The Grand Coulee Dam light show is an audio-visual spectacle unique to the Bureau of Reclamation and the US Federal Government. Its life began as a display of abstract-coloured lights illuminating the falling waters of the dam's spillways. Its production spans more than 60 years of inspiring people on the history, construction and wonder that is the Grand Coulee Dam, yet the light show or Colorama development and meaning are more than just a collection of light and music. This paper presents a historic entanglement of one of the longest running lightshow displays in the United States. Using performative and assemblage theories, it argues how the light show moves from the 'technological sublime' (Nye 1996) towards a multiplicity of agencies of light, water, sound and the concrete of the dam enabling an electric atmosphere. Using historical accounts of the show, imagery and design specifications, the paper explores the interplay of these agencies and the 'power' that is exchanged. In a time where industrial heritage is celebrated for its technical acumen and national connection, the light show provides key perspectives into new theoretical avenues of illumination and hydro assemblages. [ABSTRACT FROM AUTHOR]

Dams fall in 'installations containing dangerous forces' because of their massive impact on the environment and civilian life and property as per International humanitarian law. As such, it becomes vital for hydraulic engineers to refurbish various solutions for dam rehabilitation. This paper presents a review of a new type of weir installation called Piano Key Weir (PKW), which is becoming popular around the world for its higher spillway capacity both for existing and new dam spillway installations. This paper reviews the geometry along with structural integrity, discharging capacity, economic aspects, aeration requirements, sediment transport and erosion aspects of Piano Key Weir (PKW) as compared with other traditional spillway structures and alternatives from literature. The comparison with other alternatives shows PKW to be an excellent alternative for dam risk mitigation owing to its high spillway capabilities and economy, along with its use in both existing and new hydraulic structures. [ABSTRACT FROM AUTHOR]

This paper studies a discrete model of a large dam where the difference between lower and upper levels, L, is assumed to be large. Passage across the levels leads to damage, and the damage costs of crossing the lower or upper level are proportional to the large parameter L. Input stream of water is described by compound Poisson process, and the water cost depends upon current level of water in the dam. The aim of the paper is to choose the parameters of output stream (specifically defined in the paper) minimizing the long-run expenses that include the damage costs and water costs. The present paper addresses the important question: How does the structure of water costs affect the optimal solution? We prove the existence and uniqueness of a solution. A special attention is attracted to the case of linear structure of the costs. As well, the paper contributes to the theory of state-dependent queueing systems. The inter-relations between important characteristics of a state-dependent queueing system are established, and their asymptotic analysis that involves analytic techniques of Tauberian theory and heavy traffic approximations is provided. [ABSTRACT FROM AUTHOR]

In high dam construction projects in China, stilling basin design with an abrupt bottom drop is sometimes introduced to reduce the bottom velocity and pressure loads by generating A-type hydraulic jumps. Although the stilling basin design is not new, A-type hydraulic jumps have not been studied taking into account the air entrainment and evolution of internal air–water flow structures. This paper presents an experimental study of self-aerated A-type jumps in terms of bubble transport and free-surface fluctuations over the bottom drop. Four Froude numbers from 4.1 to 10.3 are tested for three drop heights, in addition to the flat-bottom case. Compared to the classic hydraulic jumps, A-jumps are observed with longer jump lengths and weaker free-surface fluctuations. The downward deflection of the jet-shear flow and formation of a bottom roller in the step cavity require a modification to the analytical expression of velocity and void fraction distributions. The relationship between the bubble diffusivity and jump spreading rate differs from that in classic hydraulic jumps, suggesting a faster expansion of the bubble diffusion layer than the turbulent shear flow downstream of the drop, especially for large drop heights. At large approach velocities, the reattachment of the deflected jet-shear flow to the lowered bed may cause a local rise in bubble counts downstream the bottom roller. Further increase in drop height results in a W-jump with overwhelming bottom roller over the surface roller and an arced surface jet, which is beyond the scope of this study. [ABSTRACT FROM AUTHOR]

While dam failure is a physical event with physical consequences, dams do not fail simply because something 'went wrong' physically. The physical behaviour of dams obediently follows physical laws, so, when dams fail, it is ultimately because we humans fell short in designing, building, inspecting, evaluating, maintaining, and/or operating those dams. In other words, we must think of dams as being part of sociotechnical systems and we must look at human factors in order to truly understand why dams fail and how we can prevent their failure while managing competing interests. This paper describes a human factors framework for the creation, management, and post-mortem forensic investigation of dams, and illustrates its application to the 2020 failure of Edenville Dam in the United States, an event in which loss of life was averted only because a decision was made to err on the side of caution and evacuate about 10,000 people many hours in advance of the sudden and unanticipated failure. This work is part of a Special Issue on Systems Perspectives: Clarity through Examples (see Dias 2023). [ABSTRACT FROM AUTHOR]

This paper discusses a risk evaluation for earth-fill dams due to heavy rains. The detailed method employs a flood analysis and land use data to calculate the costs of the inundation damage in the downstream areas of earth-fill dams. The procedure to calculate the damage costs requires a lot of labour. Since a huge number of earth-fill dams exist in Japan, a straightforward method is needed. The response surface method, one of the surrogate models, is proposed in this study to reduce the calculation effort. The optimum response surface is firstly evaluated by cross validation, and then the accuracy is verified by comparing the damage costs obtained by the response surface method with those obtained by the detailed method for the earth-fill dam sites. To calculate the risks, it is necessary to determine the probability of overflow failure due to heavy rains. The risk of breaching is calculated from the product of the probability of overflow failure and the estimated damage costs. The accuracy of the response surface method is assessed by comparing the risk rankings of the dams, which is the priority in dam renovations, between the detailed and the response surface methods. [ABSTRACT FROM AUTHOR]

The reliability analysis is one of the main methods for the quantitative analysis of the safety in the geotechnical engineering. This method can provide the failure probability with a clear physical meaning. Due to the complex structure of high earth-rock dams and the non-linear characteristics of the material properties, it is very difficult to perform the reliability analysis on such large nonlinear structures. Currently, there are few studies on the reliability analysis of high earth-rock dams that consider the earthquakes, the dam body deformation and the dam slope stability at the same time. In this paper, the dam cracks generated by the earthquakes are used as the criteria for the dam body seismic deformation evaluation, and the inclination method is adopted for the dam body seismic deformation analysis. The simplified Bishop method combined with the ratio of the safety margin method is used to analyze the dam slope stability. In order to consider the soil material properties, the thickness of the compressible soil layer and the uncertainty of the earthquakes, a seismic failure probability analysis method for evaluating the seismic danger of high earth-rock dams considering the dam body deformation and the dam slope stability is established based on the reliability theory. Taking a concrete face rockfill dam as an example, the method is used to analyze the seismic failure probability of the dam during the design reference period. It provides the reference for the seismic design and the risk analysis, and establishes the risk level of high earth-rock dams. [ABSTRACT FROM AUTHOR]

Building on a global research sweep of terrorist organizations' (as well as other non-state actors such as separatist and insurgent groups) use of fresh water as a target, weapon, or source of control, this paper analyzes attacks on major water projects (specifically dams and other related infrastructure) in South Asia—the region identified to have had the largest number of recorded water-related violent incidents. Focusing on India, Pakistan, and Afghanistan, and the post 9/11 period through 2019, the paper explores how large water infrastructures (and their environs) have become hot spots for violence between states that use water development projects to consolidate power, garner local loyalty, and create a national narrative and non-state actors who attempt to target these same projects to assert indigenous self-determination, subvert state power, or challenge state authority through terrorist means. Since fresh water is shared across borders, dam projects can become entangled in regional political disputes further exacerbating violent conflict between state and non-state actors. Given its impacts on water resources, climate change may act as a "threat multiplier" by enhancing local grievances, providing both government and terrorist groups additional incentives for exploitation, and further contributing to instability. The analysis provided here borrows from and contributes to the fields of development, environment and security, and terrorism studies. [ABSTRACT FROM AUTHOR]

The paper assessed the impacts of capacity building on community leadership for managing Bui National Park; and whether dam construction, resettlement, ethnicity, age, livelihood, and gender could mediate the impacts of capacity building on community leadership for managing Bui National Park. Data were gathered through multiple methods through an administration of questionnaires and interviews. The paper resolved the few capacity building opportunities on community leadership failed to meet the core needs of the dam impacted communities, including the management of the Bui National Park. Ethnicity (Nafana, Ewe, and Mo) and relocate were the only preditors of community leadership. [ABSTRACT FROM AUTHOR]

The use of temperature field to detect leakage in earth-rock dams has a low cost and high efficiency, which is crucial to the safety of dams. This paper briefly introduces the principle of temperature field leak detection, reviews the research results of temperature leak detection, and categorises the research on the detection of leakage through the temperature field of earth-rock dam into three levels: 1) technical research based on temperature field detection; 2) study on the theoretical model of temperature detection; 3) research on numerical calculations of multi-field coupling such as temperature field and seepage field. The main achievements and characteristics of various research levels are reviewed, revealing the development trends of the field of temperature field leakage detection in earth-rock dams. Consequently, UAVs mounted with infrared thermal imaging leak detection technology are integrated, and the technical scheme for patrol leak detection is noted. Finally, future research directions for the temperature field detection of earth-rock dam leakage are explored for the timely and accurate detection of the location of leakage channels and to establish an intuitive and effective judgement and identification method for dam leakage. [ABSTRACT FROM AUTHOR]

Any form of resettlement of people requires applying some governance processes to guide its implementation processes. Resettlement and governance – are entangled because acceptability and ownership of a resettlement programme by community members are associated with the manner of application of good governance principles. Several studies have focused on the impact of resettlements on affected people and communities, however, little is known about the impact of the governance principles being applied in the implementation of resettlements on the hosts. This study seeks to investigate the impact of governance principles applied in the implementation of dam-induced involuntary resettlement on host communities. A good governance principles framework was used, using the case of the Bui Dam resettlement in Ghana. Findings of the paper, obtained via a mixed-methods approach, indicate that in the Bui Dam resettlement, the governance processes failed to protect the hosts' interests as they perceived public participation and transparency to be low and no fair compensation received. The study demonstrates that governance processes of resettlements in the Global South appear feeble to protect host communities' interests. [ABSTRACT FROM AUTHOR]

This paper investigates the influence of multi-components strong motion duration on seismic performance of high concrete-faced rockfill dams (CFRDs) by fragility analysis based on the method of incremental dynamic analysis (IDA). The contributions of all compositions of earthquake excitations are considered by the definition of integrated duration based on the concept of significant duration. The nonlinear finite element model of a 2D 200-m-high CFRD is established as a case study and the vertical and horizontal displacements are selected as damage measures. Fragility curves and probabilities of two sets of 23 and 25 spectrally equivalent as-recorded bi-directional long-duration and short-duration motions are determined under different failure grades and intensities. The results show that the duration of vertical component has a certain effect on correction between strong motion duration and deformation of the dam and fragility analysis indicates that the ground motions with long duration can make more risk of failure of high CFRDs than short duration motions. Therefore, the seismic performance of high CFRDs will be reformed by taking the effect of ground motion duration into seismic design and risk assessment consideration. [ABSTRACT FROM AUTHOR]

Comprehensive evaluation of dams in a dynamic and proactive way is accepted as an effective strategy to improve dam safety. However, there is a lack of efficient and standardised approaches for managing monitoring-related information that can help to provide dynamic and reliable information for continuous dam evaluation. With the importance of digital twins (DTs) being proven in better data integration and interoperability, a DT-based approach for comprehensive dam evaluation and its data integration method based on extended industry foundation classes (IFC) are provided in this study. This paper presents a new data structure and corresponding data classification strategy, using which information required for continuous evaluation can be effectively organised. Considering that existing evaluation methods cannot fully characterise uncertainties in the evaluation process, a cloud model based comprehensive evaluation framework is proposed. In this approach, a multi-rule cloud reasoning model is utilised to evaluate monitoring points. Also, a multi-dimensional cloud model and an improved Criteria Importance Though Intercriteria Correlation (CRITIC) method are leveraged to assess evaluation indices affected by multiple factors. Finally, the results of a case study verify that the proposed DT-based solution realises a continuous dam safety evaluation, which contributes to automated and efficient dam condition monitoring. [ABSTRACT FROM AUTHOR]

This paper studies the Korean War from an environmental perspective. The paper examines the political background that aggravated environmental damage and the ways in which hydro-warfare, ecological warfare, and epidemics are interconnected. By focusing on environmental destruction during the Korean War, this research questions the view of post-1950s industrialization and urbanization as the main sources of environmental crisis on the Korean Peninsula. The paper examines some of the major wartime disasters, such as the destruction of hydroelectric and irrigation dams and epidemic outbreaks. Special attention is given to the impact of aerial bombing, which not only resulted in the deaths of millions, but also created a chain effect of environmental destruction, population displacement, flooding, famine, and epidemic outbreaks. In revisiting them, it conclusively looks at the impact that military activities have on the environment and how the Korean War foreshadowed the rise of environmental warfare during the Cold War. [ABSTRACT FROM AUTHOR]

Influenced by regional economic integration and politics, the transboundary common water resources in the lower Mekong River are being exploited by the riparian states for hydroelectric dam development at the expense of local livelihoods and the environment. Affected communities and non-governmental organisations – formed into 'transnational environmental movements' (TEMs) in the framework of transnational activism – have challenged these riparian states to abandon dam construction on the main stream of the Mekong River. This paper explores the conditions that undermine TEMs' ability to cancel dam projects in the region. This paper argues that, among several other factors, TEMs were unable to halt construction of the dam primarily due to the transnational political economic structures (TPES) of the riparian states that possess hydroelectric dams on the Mekong mainstream. TPES shape the sovereign power of the riparian states in making decisions regarding extracting economic value from the common water resource of the Mekong at the expense of the environment rather than complying with the demands of TEMs. By factoring TPES into understanding the outcomes of TEMs, this paper contributes to the understanding of political opportunity structures and transnational networks of transboundary movements, and of the political economy of the Mekong transboundary resources. [ABSTRACT FROM AUTHOR]

This paper explores the deformation behaviour of 1# toppling rock slope, located on the right bank of the Lancang River upstream of Huangdeng Hydropower Station in China. Field monitoring data show that the surficial and deep displacements of the toppling rock slope increase greatly during the second stage of the impoundment period. The deformation of the toppling rock slope in the lower part is generally larger than that in the higher part, and the displacement near the dam side is larger than that farther from dam. Furthermore, the horizontal deep displacement decreases with increasing depth of the slope. Based on the measured displacements of the toppling rock slope, the grey relational analysis (GRA) method is used to explore the correlations between the slope displacement rate and the relevant influencing factors, including rainfall, water level fluctuation, time and air temperature. The results show that the main control factors influencing the slope displacement rate are the water level fluctuation followed by rainfall. The findings may suggest that the 1# toppling rock slope has the potential of hydrodynamic instability, and the water level fluctuation caused by the reservoir operation should be fully concerned to avoid the instability of the toppling rock slope. [ABSTRACT FROM AUTHOR]

This paper analyses the feasibility of estimating the fundamental frequency of an 85 m high cycloned-sand tailings dam located in the Central-North area of Chile using the single-station H/V Spectral Ratio Method (HVSR), calculated from seismic ambient noise and earthquakes recorded by a temporal seismic array deployed along the embankment crest, the downstream slope, and the dam toe, directly over the foundation soil. The fundamental vibration frequencies obtained from the HVSRs show consistency with results from the Standard Spectral Ratio method (SSR) calculated between the crest and the toe using the available earthquake records, particularly in the dam central part. [ABSTRACT FROM AUTHOR]

This review paper focuses on the question of what will happen to the future water resource system of Grand Renaissance Dam of Ethiopia based on the projected hydrology of the Upper Blue Nile River basin. For this, the hydrological extremes, the baseline hydrological trends, and projected hydrological extremes of the Upper Blue Nile River basin were reviewed from various published and unpublished sources. Changes in the future hydrology of the Upper Blue Nile River basin due to climate change or any other natural or manmade modification of the river basin deserve concerted attention in the future water resources system of the Grand Renaissance Dam of Ethiopia, because the water resources of the dam mainly depend on the water potential nature of the Upper Blue Nile River basin. [ABSTRACT FROM AUTHOR]

Featured with the harmonic sinusoidal function to reflect temperature effects, the hydrostatic-season-time (HST) model is often used to monitor the concrete gravity dam health, but it does not take account of the effects of environment temperatures in real-term and has flaws especially when applied in conditions of significant temperature variations. A model of Sparrow Search Algorithm optimized error Back Propagation neural network (SSA-BP) based on the hydrostatic-temperature-time (HTT) model is proposed in this paper for predicting the concrete gravity dam displacement using the long-term environment temperature variable sets to reflect temperature effects. Successive Projections Algorithm (SPA) is used for the first time for feature selection on long-term temperature variables to further optimize the model (as SPA-SSA-BP). Through a case study with the practical observed data from a reality high concrete gravity dam, the effectiveness of the new model is verified, suggesting that HTT-based SSA-BP models have better performance than HST with the best result obtained when using the 2-year long variable sets. The SSA-BP model has much lower error in predicting the concrete dam displacement than Multiple Linear Regression (MLR). The arithmetic speed and prediction accuracy of the SPA-SSA-BP model is optimized as it can minimize the collinearity among feature variables in the long-term HTT variable sets, bring down the input variable dimension close to the level of HST, and diminish the redundant data information. [ABSTRACT FROM AUTHOR]

The January 2011 flood event that impacted southeast Queensland is amongst the most extensive and severe floods in terms of loss of life and property damage that the region has experienced, despite it being only the eighth highest flood on record at the Brisbane City Gauge. The spring of 2010 was the wettest on record for Queensland, New South Wales, and the Murray-Darling Basin (Bureau of Meteorology 2011a) at that time. The flood mitigation dams in the region, Somerset Dam and Wivenhoe Dam, had to be operated for flood mitigation purposes during October 2010, which was the first occasion since February 2001 that Wivenhoe Dam had been called into action due to the Millennium Drought. The wet October was followed by a very dry November which, in turn, was followed by the wettest December on record for Brisbane. Somerset Dam and Wivenhoe Dam were again pressed into action on three separate occasions during December 2010. The resultant releases ensured that only minor flooding resulted in the Lower Brisbane River during these events. However, on the 5th of January 2011, another rainfall event started to unfold across the catchments of the dams. By the 10th of January 2011, an upper-level low combined with a humid easterly flow to bring very heavy rainfall and flash flooding to southeast Queensland and northeast New South Wales. The heaviest falls were in the areas north and west of Brisbane, with three-day totals exceeding 200 mm over most of the Brisbane River catchment. This rainfall event resulted in a flood of record in the Upper Brisbane River and Upper Lockyer Creek catchments that sadly resulted in a substantial loss of life in Toowoomba and the Lockyer Valley, and which required record releases from Wivenhoe Dam. The resultant downstream flooding saw some 14,000 properties impacted, principally in the Lockyer Valley Regional Council, Somerset Regional Council, Brisbane City Council, and Ipswich City Council local government regions. Flood damage was estimated to be around $2.53 billion. This paper discusses the event as it unfolded and the subsequent judicial inquiries, engineering reviews, and legal proceedings that resulted from the consequences of the operation of Somerset Dam and Wivenhoe Dam. [ABSTRACT FROM AUTHOR]

Mine tailings dams are surface impoundment structures consisting of raised embankments that are built to contain mine tailings and mill effluents. In the past, many failures of these iron ore mine tailings storage facilities/dams have been reported worldwide in different forms. In this paper, an attempt has been made to review the failure modes, mechanisms and possible solutions to enhance the stability and safety of iron ore tailings dams. A comprehensive investigation has been carried out on 16 failure cases of such dams that were reported from 1917 to the current period. Additionally, mineralogy of iron ore tailings has been provided. The analysis of the past failures shows that most failures took place as a result of slope instability, overtopping, liquefaction-related instability, foundation movement and some form of structural failure. It has been found that 31.25% of iron ore mine tailings dams collapsed due to slope instability, 18.75% due to overtopping, 6.25% due to liquefaction-related instabilities, 6.25% due to foundation failure, 6.25% due to erosion, and 6.25% due to structural failure. In 25% of the failure cases, the causes have been unknown. An attempt is also made here to present prevention and remediation measures for avoiding failures and the associated negative environmental impacts in future. [ABSTRACT FROM AUTHOR]

The extraction of large dam candidate regions is critical for broad-scale efforts to rapidly detect large-area dams. The framework proposed in this paper attempts to combine random forest classification models and spatial analysis methods with large dam candidate area extraction methods for large-scale areas. First, we studied the combination of optical, microwave, texture, and topographic features of the dam and constructed a multisource remote sensing and topographic feature vector of the dam. Secondly, we constructed random forest classifiers in different study areas and evaluate their performance. Then we explored the geographic characteristics of the dams and their relationships with other features. Finally, we introduced the spatial analysis method to constrain the large dam candidate area. The proposed framework was tested in a total area of 968,533 km2 in five countries and achieved promising results, which constrained the candidate area to less than 1.06% of the total area. We calculated the completeness rate of large dams using the multi-source dam datasets. The framework achieved a completeness rate of more than 97.62%. Our results show that the entire framework is reliable for automated and fast large dam candidate area acquisition based on data from open remote sensing products. [ABSTRACT FROM AUTHOR]

Forrest Merton Holly Jr dealt extensively with numerical modelling of unsteady flows and dispersion processes associated with the operation of hydropower and thermal power plants, and often with alluvial sediment transport by rivers. His expertise, energy, and genial personality led him to become President of the International Association of Hydraulic Engineering and Research (IAHR) during 2000–2003. Holly's last hydraulics project engaged his expertise and was done with the friendly aplomb for which he was well known. This forum paper portrays Holly engaged in his last project, which involved the practical application of numerical modelling of unsteady flow to and through a navigation dam. [ABSTRACT FROM AUTHOR]

Fishways are an important link for the reestablishment of river continuity, interrupted by transverse structures e.g. weirs, dams and hydropower plants. The meander fishway and vertical slot fishway are two types commonly constructed in Germany, which create distinctive flow regimes to allow upstream passage. Nonetheless minor environmental or constructional alterations create unforeseen flow regimes, whose impact on fish behaviour is still uncertain. One approach is to obtain different flow aspects for fish by evaluating numerous parameters with the IPOS-framework in laboratory experiments. The framework provides various identification parameters and methods, which must be considered with regard to fish behaviour. This paper expands the experimental approach by using numerical simulations with OpenFOAM on one meander and two vertical slot fishways and employs the evaluation methods stated in the IPOS-framework. The results shows clear differences between the fishways, providing an advanced numerical evaluation method to objectively compare turbulent flows in the models. The 3D-hydronumerical evaluation of 1:1 scaled fishways using the IPOS-framework is a novelty so far and can be used to improve present and future fishway constructions. [ABSTRACT FROM AUTHOR]

This paper discusses the unique replacement of three historical bridge spans across the Hracholusky dam in the Czech Republic. The erection of the bridge was performed using longitudinal launching of a new bridge structure onto the old one, connecting and rotating the structure around a longitudinal axis before removing the old span. [ABSTRACT FROM AUTHOR]

Stepped spillways have become increasingly popular due to the low-cost of construction and high efficiency. A stepped spillway is a hydraulic structure that is an integral part of the dam that allows the safe passage of overtopping flows. In this paper, an experimental study was employed to investigate the stepped spillway with four steps of 32 cm height and 54 cm width contracted by wing wall width (C) = 0.2 from the width of the flume. Eighteen runs were carried out considering different positions, heights, and widths of the baffle to increase the energy dissipation resulting from this contraction stepped spillway. The results indicated that the best position of baffles was (a/y2) = 1.4, the relative baffles height was (hb/y1) = 0.95, and the best relative baffles widths (wb/W) = 0.68, compared with cases of contraction stepped spillway without baffles. The results showed that the baffles on the stilling basin downstream stepped spillway increase the energy dissipation. Simple formulae were also deduced to evaluate the energy parameters. [ABSTRACT FROM AUTHOR]

This paper considers a problematic dynamic in the protection of natural World Heritage properties for sites that also possess significant cultural assets, but that fall short of the World Heritage designation 'outstanding universal value' standard for cultural significance. The destruction of cultural heritage places in natural settings is a global concern and we use an Australian case study to illustrate the argument that cultural assets located within natural properties should be given an allied protection status. We argue that protection problems arise, represented by a nature/culture binary trope, despite significant progress in using more holistic approaches, as exemplified by cultural landscapes. To demonstrate our argument, we consider controversy surrounding a development proposal within the Greater Blue Mountains World Heritage Area (GBMWHA), located in the state of New South Wales, Australia. We find that a development proposal to raise a storage dam wall triggers significant problems for protecting both natural and cultural heritage features across the GBMWHA landscape and, in this context, we recommend a reconsideration of the rigid natural/cultural heritage binary of World Heritage classifications. [ABSTRACT FROM AUTHOR]

China's first hydroelectric station began producing electricity in 1912, a year better known for marking the end of imperial rule and the advent of republican governance. Located a short distance outside of the southwestern city of Kunming, Shilongba (Stone Dragon Dam) was a cross-cultural endeavour that involved long-distance encounters of both materials and expertise that spanned not just vast expanses within China, but also a world divided by competing imperial interests. The technologies involved were at once both new and old. Turbines and dynamos represented the latest in German innovation, but the techniques used to carve the canal and lower the water table had been perfected over centuries. A history of Shilongba thus allows us to approach China's transition from Empire to Republic not merely as a political process but also as one of multiple makings – of state, technology, energy, society, and not least, history itself. This paper explores these multiple makings, focusing on the first phase of construction from 1908 to 1912, when a dam was constructed, a canal dug, and the first power station established. [ABSTRACT FROM AUTHOR]

In this paper, the influence of the mechanical properties of masonry in the structural behavior of old masonry dams in Mexico is evaluated. Mexico has an important number of masonry dams, which were constructed from seventeenth century to nineteenth century and continue to operate until now. Two different typologies of typical dams in Mexico were analyzed. The first typology corresponds to a dam with inclined faces (upstream and downstream) and the second one corresponds to a dam with a vertical face upstream and an inclined face downstream. The selected dams were analyzed by traditional methods, where the resultant of all forces acting on the dam must lie in the third middle of the base and the hypothesis of no tension material is assumed. Sometimes, this approach is too conservative and mostly does not reflect the real structural behavior of the dam. Thus, 2D models of both dams by means of a semi–discrete approach were performed. Considering the non-linear behavior a parametric study was made in order to identify the mechanical properties that have more influence on the structural behavior. Parametric analyses show that the tensile strength of the masonry is the property of greater influence on the structural behavior. [ABSTRACT FROM AUTHOR]

This paper presents a methodology to evaluate the seismic reliability of geostructures in an optimal way. Taguchi design of experiments are adopted to find the most efficient and cost-effective combination of material properties in the uncertainty domain. Twelve uniform and mixed design models are tested. A polynomial-based response surface meta-model is built for each one and the accuracy of perdition is examined using 10,000 Monte Carlo simulations. A two-dimensional gravity dam is used as a vehicle for probabilistic transient analyses. The ground motion record-to-record variability is added as well using over one hundred earthquake records selected based on probabilistic seismic hazard analysis. Dynamic sensitivity of epistemic random variables are evaluated for the first time. Finally, an efficient and practical procedure is proposed in order to determine the reliability index of the geostructures. This approach, in fact, can be generalised for any type of engineering structures dealing with multi-hazard problems. [ABSTRACT FROM AUTHOR]

Deterministic seismic analysis of dam-foundation-water does not usually reflect the true behavior of the system due to presence of different epistemic uncertainties. On the other hand, the crude Monte Carlo simulation (CMCS) of such a system is computationally expensive and often practically impossible. This paper investigates the potential application of so-called design of experiments (DOE) in order to develop appropriate metamodels and present an explicit expression of dam response. More than ten DOE techniques are compared and contrasted. Accuracy of metamodels is evaluated using about 120,000 finite element simulations from CMCS. Furthermore, the application of several sampling reduction techniques (i.e. Latin Hypercube, Sobol, and Halton) is evaluated. Next, the impact of polynomial degree is studied for an actual gravity dam with five random variables. Results are generalised for 12 different dam classes where the displacements, stresses and failure modes are quantified. Last but not least, a metamodel is proposed for seismic uncertainty of gravity dam in which the dam response is estimated using different features of the input ground motions. [ABSTRACT FROM AUTHOR]

The Hardian solutions to the excessive abuses of common-pool resources are still being contested. However, studies on governance and management of community irrigation facilities as a "common" in developing countries is limited. Contributing to literature on irrigation water management in the Global South, this paper examines the role of communities in the governance and management of small-scale irrigation dams in the Upper East Region of Ghana. The study employs a qualitative approach to research with 25 interviews and seven Focus Group Discussions (FGDs). Using a thematic approach to analysis, the study reveals that smallholder farmers through the Water Users' Associations (WUAs) have defined user boundaries and instituted ground rules and regulations to enable them to sustainably manage these water resources for their activities of agriculture. Further results revealed that irrigable land for dry season gardening was equitably shared among farmers who are members of WUA, and as a result, minimized possible conflicts among the resource users. The study recommends the need for the Ministry of Food and Agriculture and the Ghana Irrigation Authority to provide more technical support to WUAs in the Upper East Region of Ghana to enable them to better manage these water resources. [ABSTRACT FROM AUTHOR]

This contribution offers a new perspective on the planning of post-colonial Africa focusing on the role of Italy. Weak and underdeveloped due to significant war losses, Italy could not rely on the investment potential of its Atlantic allies. Moreover, after WWII, its political influence across the continent had substantially reduced to zero. Yet, it emerged as an unexpected outsider whose eccentric – and somehow contradictory – position has been often largely underestimated. The peculiarity of the Italian condition, in fact, has been crucial to implement and put the Atlantic developmental vision in practice. To some extents, Italy has been the veritable builder of post-colonial Africa, first as a free-lance actor and then as a partner of the global agencies (IBRD, UNESCO) involved in the re-making of the continent. How could a nation substantially underdeveloped like Italy emerge as one of the leaders in implementing development planning actions abroad, although not being directly involved in decision-making process? This paper aims at answering these questions focusing on logistical, organizational and planning competences deployed by Italian corporates and technicians during the construction of four African major dams, between 1956 and 1966. [ABSTRACT FROM AUTHOR]

There is ample recognition of the risk inherent in our very existence and modes of social organization, with a reasonable expectation that implementing risk governance will result in enhanced resilience as a society. Despite this, risk governance is not a mainstream approach in the infrastructure sector, regardless of the increasing number of peer-reviewed published conceptualizations, mature procedures to support its application, or public calls to cope with systemic risks in our modern societies. This paper aims to offer a different view on the issue of risk governance, with focus in the analysis of the root causes of its relatively low degree of implementation in the infrastructure sector. We later analyze the impact of such essential causes, which we have grouped and labeled as the ontology, the concerns, the anathemas, and the forgotten, in the specific field of large dams. Finally, we describe the journey toward risk governance in the specific field of large dams, thus supporting the ultimate objective of this paper to facilitate an evidence-based approach to successful risk governance implementation within and outside the dam sector. [ABSTRACT FROM AUTHOR]

Scholars are rarely able to examine anti-dam movements that result in project suspensions or cancellations since these cases are rare empirically. Yet, they are central to understanding how anti-dam movements can succeed. This paper analyzes the movements against Myanmar’s Myitsone Dam and Thailand’s Kaeng Suea Ten Dam. Likely the most successful anti-dam movements in Southeast Asia in recent years, they achieved suspension over 6 and 37 years, respectively. The research is based on 60 semistructured interviews carried out over a period of 8 months. Leveraging thinking from both the constructionist and structural schools within the field of social movement studies, it is found that the framing of the Myitsone Dam as a project threatening the national cultural heritage of Myanmar (in combination with political change in the country in 2010/2011) largely explains the movement’s success. Meanwhile, the set of sophisticated tactics (includinginter aliademonstrations,Thai Baanresearch, 24/7 monitoring of the dam site, and spiritual activities) was decisive for the efficacy of the movement against Thailand’s Kaeng Suea Ten Dam. [ABSTRACT FROM AUTHOR]