Large Dam Reservoirs Research Articles

Beyond dams: Assessing integrated water storage in the Shashe catchment, Limpopo River Basin

Study regionThe Shashe catchment, Limpopo River Basin, Botswana, and Zimbabwe. Study focusThe Shashe catchment is the third largest flow contributor to the Limpopo River Basin. Water availability in the Shashe catchment is highly seasonal due to high seasonal rainfall variability. The seasonality and inter-annual variability cause shortfalls (demand exceeds the average water availability) in certain months and years. Storage is needed to bridge the seasonal water availability “gap” and mitigate the deficits in drought years, i.e., inter-annual variability. While the need for water storage through grey infrastructure such as dams has long been known, there is growing recognition of the need for approaches to water storage that capitalize on all storage types. However, the current capacity to plan in ways that utilize all storage types is limited. The analyses conducted for this paper assessed the volume and spatial and temporal variability of different storage options – large and small dams, sand dams, soil moisture, and aquifers – in the Shashe catchment of the Limpopo River Basin. An integrated SWAT-MODFLOW model and remote sensing approach were developed for 2015–2020. New hydrological insights for the regionThe total annual water storage in the Shashe catchment is approximately 44,000 Mm3, dominated by groundwater. The annual storage is about 42,000 Mm3 in aquifers, 1500 Mm3 in soil, 700 Mm3 in large dam reservoirs, 45 Mm3 in small dams/ponds, and 0.13 Mm3 in sand dams. There is high seasonality in water storage availability. Soil moisture storage is at its maximum from January to March and lowest from July to September. Dam storage is at its maximum from March to May, and the water storage is relatively stable throughout the year. Aquifer storage is relatively stable during the dry seasons compared to other storage options. Optimizing water use considering the seasonal variation in different storage types could improve water availability and climate resilience.

Influence of Rock Slide Geometry on Stability Behavior during Reservoir Impounding

Assessing the stability behavior of deep-seated rock slides in the surroundings of large dam reservoirs requires an understanding of the geometry, the kinematics, the groundwater situation, and the rock mass and shear zone properties. This study focuses on the influence of rock slide geometry on stability evolution during initial reservoir impounding. Therefore, nine different rock slide models, mainly taken from published case studies with a well-explored geometry, were analyzed. Based on the assumption that the rock slides are close to limit equilibrium in a no-reservoir scenario, reservoir impounding causes a reduction in the factor of safety (FoS). The results show a large impact of the water level for rotational slides where the majority of the rock mass is located at the lower part of the slope. This results in a maximum reduction in the FoS of up to 12%. In contrast to this, translational rock slides are less affected by reservoir impounding. The stability analysis shows that the change in FoS is strongly controlled by the kinematics of the rock slide and the geometry near the foot of the slope. Consequently, a comprehensive in situ investigation of the geometry and kinematics is necessary in order to reliably assess the influence of initial reservoir impounding.

Decomposition and Holt-Winters Enhanced by the Whale Optimization Algorithm for Forecasting the Amount of Water Inflow into the Large Dam Reservoirs in Southern Thailand

This study introduces hybrid forecasting models integrating the Whale Optimization Algorithm (WOA) with Holt-Winters (HW) and decomposition methods, applied in both additive and multiplicative models, for time series forecasting. Focusing on monthly water inflow into four dam reservoirs in Southern Thailand, the study compares these hybrid models against classical statistical models, Grid Search for Holt-Winters (Grid-HW) and Classical Decomposition (Classic-D). The analysis comprises two phases: the training dataset phase and the testing dataset phase. In the training phase, WOA demonstrates superior parameter optimization, enhancing both HW and decomposition methods, resulting in lower Mean Absolute Error (MAE) values compared to classical models. In the testing phase, performance metrics such as Root Mean Square Error (RMSE), MAE, and Symmetric Mean Absolute Percentage Error (sMAPE) are employed. The findings reveal that the Whale Optimization Algorithm with Holt-Winters (WOA-HW) and Decomposition (WOA-D) models surpass classical approaches in long-term forecasting accuracy for three dam reservoirs. Over 24 data points, the WOA with Multiplicative Holt-Winters (WOA-HWx) is optimal for Pran Buri dam, the WOA with Additive Decomposition (WOA-D+) for Bang Lang dam, and the WOA with Multiplicative Decomposition (WOA-Dx) for Kaeng Krachan dam. The Box-Jenkins approach, further refined through a Box-Cox transformation employing a natural logarithm, emerged as the superior forecasting model for Rajjaprabha dam. This model satisfied all critical statistical criteria, including normality of residuals (Anderson-Darling: 0.359, p-value: 0.433), homoscedasticity (Levene's test: 1.24, p-value: 0.274), independence (Ljung-Box test: 14.10, p-value: 0.169), and zero mean (t-test: -0.39, p-value: 0.702), establishing its robustness and reliability for forecast analysis.

Delta lobe development in response to changing fluvial sediment supply by the second largest river in Vietnam

While the importance of sediment supply to river delta evolution is well recognized, the extent to which sediment from upstream sources contributes to the subaerial and subaqueous components of its delta is not yet fully comprehended. To investigate this issue, the present study analyzed satellite images (Landsat) spanning from 1975 to present and nautical charts in different periods to examine the morphological evolution and its relationship with changes in river sediment loads of the Ba Lat delta lobe, located on the central coast of the second largest river system (Red) in Vietnam. We proposed a hybrid approach to estimate suspended sediment entering the sea via the Ba Lat mouth, based on a combination of one-line theory and long-term observation from a gauging station. The results show a significant reduction (∼91.5 %) in annual sediment load over the entire 64-year estimation period (1958–2021), which is associated with the operation of large dam-reservoirs upstream. The evolution of the Ba Lat delta lobe was found to be highly correlated with sediment load, with a huge sediment supply from the Red River causing the delta lobe to move seaward at a rate of more than 100 m/yr and the deltaic land area to accrete at a rate of 117 ha/yr between 1975 and 1990. However, since the early 1990s, the annual sediment flux has reduced of 57 %, resulting in more than 50 % of the delta lobe's shoreline experiencing severe erosion. The current amount of sediment load delivered to the sea (1.4 × 106 m3/yr) is insufficient to prograde the delta lobe, which could lead to continued land loss in the future. We attribute these erosions mainly to the reduced river sediment supply, generated by the large dam-reservoirs located upstream of the delta. The study suggests that these results and methods can inform coastal management and enhance understanding of delta lobe evolution by providing insights into changes in shoreline position, land area, and subaqueous component.

Impact of large dam reservoirs on slight local season shifting (case study: Three Gorges Dam)

Impact of large dam reservoirs on slight local season shifting (case study: Three Gorges Dam)

Remotely sensed reservoir water storage dynamics (1984–2015) and the influence of climate variability and management at a global scale

Abstract. Many thousands of large dam reservoirs have been constructed worldwide during the last 70 years to increase reliable water supplies and support economic growth. Because reservoir storage measurements are generally not publicly available, so far there has been no global assessment of long-term dynamic changes in reservoir water volumes. We overcame this by using optical (Landsat) and altimetry remote sensing to reconstruct monthly water storage for 6695 reservoirs worldwide between 1984 and 2015. We relate reservoir storage to resilience and vulnerability and investigate interactions between precipitation, streamflow, evaporation, and reservoir water storage. This is based on a comprehensive analysis of streamflow from a multi-model ensemble and as observed at ca. 8000 gauging stations, precipitation from a combination of station, satellite and forecast data, and open water evaporation estimates. We find reservoir storage has diminished substantially for 23 % of reservoirs over the three decades, but increased for 21 %. The greatest declines were for dry basins in southeastern Australia (−29 %), southwestern USA (−10 %), and eastern Brazil (−9 %). The greatest gains occurred in the Nile Basin (+67 %), Mediterranean basins (+31 %) and southern Africa (+22 %). Many of the observed reservoir changes could be explained by changes in precipitation and river inflows, emphasizing the importance of multi-decadal precipitation changes for reservoir water storage. Uncertainty in the analysis can come from, among others, the relatively low Landsat imaging frequency for parts of the Earth and the simple geo-statistical bathymetry model used. Our results also show that there is generally little impact from changes in net evaporation on storage trends. Based on the reservoir water balance, we deduce it is unlikely that water release trends dominate global trends in reservoir storage dynamics. This inference is further supported by different spatial patterns in water withdrawal and storage trends globally. A more definitive conclusion about the impact of changes in water releases at the global or local scale would require data that unfortunately are not publicly available for the vast majority of reservoirs globally.

Inter-estuarine and seasonal to decadal variations of heavy metal pollution in the Gulf of Cambay, India

Toxic heavy metals adsorbed preferentially onto suspended sediments enter our food chain by bio-assimilation in coastal ocean organisms. To decipher metal pollution status in the Gulf of Cambay (food hub of India) under rising anthropogenic pressure, we present seasonal abundances of Ti, Cr, Co, Ni, Cu, Zn, Cd, and Pb in > 150 samples of suspended sediments (> 0.45µm) collected in four seasons (2016-2017) from two large estuaries (Narmada and Tapi). The suspended sediments of both the estuaries generally show low heavy metal pollution (Igeo < 1). The hotspots of moderate-to-high pollution of Pb (Igeo < 4), Cd (Igeo < 3), and Zn (Igeo < 2) are found at salinity < 2, and those of Co (Igeo < 2) at salinity ~ 20-30 in the Tapi estuary during the non-monsoon seasons indicating their decoupled sources in Surat. The PLI values show no or little seasonality in the overall metal pollution status of both the estuaries. A comparison with the literature data suggests that suspended sediments efficiently capture active metal pollution in Indian estuaries. Furthermore, a recent decline (2004-2017) in estuarine metal pollution in the Gulf of Cambay found in this study could be due to enhanced organic matter supplies by enhanced urban sewage discharge and/or more trapping of contaminated riverine sediments upstream of the newly built large dam reservoirs counteracting the growth of anthropogenic metal inputs in the Narmada and Tapi watersheds. The data scarcity of heavy metal concentrations in suspended sediments limits reporting unambiguously the current pollution status of other major Indian estuaries.

The impact of large and small dams on malaria transmission in four basins in Africa

Expansion of various types of water infrastructure is critical to water security in Africa. To date, analysis of adverse disease impacts has focused mainly on large dams. The aim of this study was to examine the effect of both small and large dams on malaria in four river basins in sub-Saharan Africa (i.e., the Limpopo, Omo-Turkana, Volta and Zambezi river basins). The European Commission’s Joint Research Center (JRC) Yearly Water Classification History v1.0 data set was used to identify water bodies in each of the basins. Annual malaria incidence data were obtained from the Malaria Atlas Project (MAP) database for the years 2000, 2005, 2010 and 2015. A total of 4907 small dams and 258 large dams in the four basins, with 14.7million people living close (< 5 km) to their reservoirs in 2015, were analysed. The annual number of malaria cases attributable to dams of either size across the four basins was 0.9–1.7 million depending on the year, of which between 77 and 85% was due to small dams. The majority of these cases occur in areas of stable transmission. Malaria incidence per kilometre of reservoir shoreline varied between years but for small dams was typically 2–7 times greater than that for large dams in the same basin. Between 2000 and 2015, the annual malaria incidence showed a broadly declining trend for both large and small dam reservoirs in areas of stable transmission in all four basins. In conclusion, the malaria impact of dams is far greater than previously recognized. Small and large dams represent hotspots of malaria transmission and, as such, should be a critical focus of future disease control efforts.

Historical pond systems as long-term composite archives of anthropogenic contamination in the Vrchlice River, Czechia

River damming has numerous benefits and adverse consequences. Unlike large dam reservoirs whose construction peaked in the twentieth century, historical ponds and their accumulated legacy sediments span much longer time periods. Small ponds in many areas worldwide are sinks for anthropogenic pollutants and affect sediment delivery to downstream river reaches. Thousands of ponds cover an area of >0.2 % of the territory of Czechia, equal to the area of its ten largest dam reservoirs. This paper reports a sequence of constructed and removed pond dams along the Vrchlice River, Czechia, and their use as sedimentary archives, in order to reconstruct the long-term (>200 yr) history of contamination. Historical maps, geophysical profiles, activities of caesium-137 isotope, grain size, and sediment geochemistry in 16 sediment cores enabled the reconstruction of contamination in the pond, dam reservoir, and floodplain sediments since ∼1780. Contamination by lead, copper, zinc, arsenic, and cadmium from atmospheric, geogenic and agricultural sources increased since ∼1850 peaked in the 1970s and 1980s, and then decreased slightly. Polycyclic aromatic hydrocarbons and pesticides polluted post-1970 sediments, reflecting their use in agriculture. The removal of dams resulted in the rapid incision of newly formed river channels into the old pond deposits. Following the reinstatement of dams, channels filled rapidly (up to 5.2 cm/yr) with new lacustrine sediment, whereas sediment accumulated slowly (<0.4 cm/yr) outside the channels. Upon dam removal, contaminated channel-fill sediment likely redistributed into the water course. As ponds are complex depositional systems with the heterogeneous distribution of sediment and associated contaminants, active and extinct ponds are promising long-term sedimentary archives that can extend understanding of human interactions with Earth systems.

Performance of Hydrodynamics Flow on Flip Buckets Spillway for Flood Control in Large Dam Reservoirs

Flip buckets are usually used in high head dams to dissipate the destructive energy of high speed jets. These structures are fixes at the end of the outlet conduits to direct the moving jet into the atmosphere. The process of energy dissipation also resumes, while the jet entering into its downstream plunge pool. Although studies of flow over flip buckets turn back to many years ago, but still there are uncertainties regarding the flow behaviour over these structures with various geometries and flow conditions. In this study, experimental measurements of static and dynamic pressures and their distribution over these structures are investigated. Measurements were made along two different simple flip buckets with various Froude numbers to determine the effects of the geometry and flow characteristics on pressure field. Maximum pressures are also presented and the results are compared with those of other investigations. The results of this study can be used to increase the safety of large dams that remain sustainable in the process of exploitation such as irrigation, human consumption, industrial use, aquaculture, and navigability. Doi: 10.28991/HEF-2020-01-01-05 Full Text: PDF

Gully development on large dam reservoir shores: dynamics, interaction, and mechanisms

ABSTRACTThe shores of the Bratsk reservoir are widely affected by bank gullies. We monitored the short- and medium-term gully dynamics at three key sites. The interaction of karst-erosional, aeolian-erosional, and gully and shore erosion processes were determined and presented as conceptual models. Gully and shore erosion were the dominating processes in the Rassvet site in the period of heavy rainfall and the maximum shore edge retreat at high water level stand (2009–2010). During 2011–2013 aeolian process prevailed over erosion due to small rainfall and low water-level stand, and aeolian material accumulated in the gullies. A high water-level period at the Ulei site resulted in shore edge retreat, hanging of gully mouths, formation of wave-cut holes in the shore scarp, and rejuvenation of retrogressive erosion in gully thalwegs. The combined action of karst and gully erosion processes led to a maximum increment in gully size (4486.34 m3), recorded at the Khadakhan site in 2004–2008 (at periods of reservoir water-level lowering following water saturation of shore massif at high water levels). This case study shows that the dynamics of the processes, their interactions, and environmental changes are characterized by a certain cyclicity corresponding to water-level changes.

Environmental contaminants in fish species from a large dam reservoir and their potential risks to human health

The residue levels of antibiotics, metals and organochlorine pesticides (OCPs) were investigated in six fish species from the Karakaya Dam Reservoir, Turkey. Among monitored antibiotics, only enrofloxacin and ofloxacin were detected in muscle of fish species. Enrofloxacin levels in positive samples ranged from 0.0034 to 0.0073 mg/kg. It was detected in four fish species (trout barb, common carp, chub and Euphrates barbell), while ofloxacin was only found in common carp with the concentration of 0.0072 mg/kg. Both enrofloxacin and ofloxacin levels were below the maximum residue levels. No detectable residues of any OCPs were found in fish species. The highest toxic metal (As, Cd and Pb) content was detected in Euphrates barbell (0.103 mg/kg). Arsenic, Cd, Cr, Cu, Pb and Zn levels were well below the maximum permissible limits. The levels of antibiotics and metals found in fish species in the present study were generally lower than or comparable to those reported in other water bodies. According to estimated daily intake and hazard quotient values, antibiotics and metals detected in these wild fish species do not appear to pose a serious risk to public health.

Impact of climate change on the persistent turbidity issue of a large dam reservoir in the temperate monsoon region

Long-term discharge of turbid water from reservoirs after flood events is a major socioenvironmental problem in many countries, including Korea. This study used a suite of mathematical models to simulate the fate of turbidity flows in the Soyanggang Reservoir in Korea, an important source of drinking water for the Seoul Capital Area, in response to extreme floods based on the Representative Concentration Pathway 4.5 climate scenario. It evaluated the effectiveness of the selective withdrawal facility (SWF), installed recently in the Soyanggang Reservoir to control persistent turbidity. Extreme floods with a maximum daily inflow rate greater than the historical maximum observed in 2006 were projected to occur four times in this century. The fate and transport of turbidity flows were highly influenced by both the thermal stability of the reservoir and the season in which the flood event occurred. Thus, SWF operations should consider the timing of extreme events (i.e., the imminence of the autumn turnover) to mitigate the impact of high turbidity on the water supply and downstream ecosystem. It was found to be ineffective under extreme events if these occurred in two consecutive years. Current reservoir operations, which rely heavily on the SWF, are likely to be inadequate to overcome the negative effects of extreme-turbidity events on reliably providing safe water supplies. Coping with the worst event expected to occur in the future would require additional countermeasures such as bypassing high-turbidity water.

Schistosomiasis in the Senegal River basin

Schistosomiasis in the Senegal River basin

Surface water quality monitoring in a large dam reservoir, Poland

Surface water quality monitoring in a large dam reservoir, Poland

Dynamics of Phosphorus-Turbid Water Outflow and Limno-Hydrological Effects on Hypolimnetic Effluents Discharging by Hydropower Electric Generation in a Large Dam Reservoir (Daecheong), Korea.

Dynamics of Phosphorus-Turbid Water Outflow and Limno-Hydrological Effects on Hypolimnetic Effluents Discharging by Hydropower Electric Generation in a Large Dam Reservoir (Daecheong), Korea.

The influence of particles recycling on the geochemistry of sediments in a large tropical dam lake in the Amazonian region, Brazil

As a result of over-erosion of soils, the fine particles, which contain the majority of nutrients, are easily washed away from soils, which become deficient in a host of components, accumulating in lakes. On one hand, the accumulation of nutrients-rich sediments are a problem, as they affect the quality of the overlying water and decrease the water storage capacity of the system; on the other hand, sediments may constitute an important resource, as they are often extremely rich in organic and inorganic nutrients in readily available forms. In the framework of an extensive work on the use of rock related materials to enhance the fertility of impoverish soils, this study aimed to evaluate the role on the nutrients cycle, of particles recycling processes from the watershed to the bottom of a large dam reservoir, at a wet tropical region under high weathering conditions. The study focus on the mineralogical transformations that clay particles undergo from the soils of the drainage basin to their final deposition within the reservoir and their influence in terms of the geochemical characteristics of sediments. We studied the bottom sediments that accumulate in two distinct seasonal periods in Tucuruí reservoir, located in the Amazonian Basin, Brazil, and soils from its drainage basin. The surface layers of sediments in twenty sampling points with variable depths, are representative of the different morphological sections of the reservoir. Nineteen soil samples, representing the main soil classes, were collected near the margins of the reservoir. Sediments and soils were subjected to the same array of physical, mineralogical and geochemical analyses: (1) texture, (2) characterization and semi-quantification of the clay fraction mineralogy and (3) geochemical analysis of the total concentration of major elements, organic compounds (organic C and nitrogen), soluble fractions of nutrients (P and K), exchangeable fractions (cation exchange capacity, exchangeable bases and acidity) and pH(H2O).There is a remarkable homogeneity in the sedimentary distribution along the reservoir in terms of the texture and mineralogy of the clay fraction and of the chemistry of the total, soluble and exchangeable phases. These observations contrast with the physical, morphological and chemical heterogeneity of the soils and the setting lithology. Most of the sediments has a higher contribution of fine-grained material and the mineralogy of the clay fraction is dominated by kaolinite in soils and kaolinite and illite in sediments, followed by lesser amounts of gibbsite, goethite, and metahaloisite and by small/vestigial contents of chlorite and smectite. The sediments are mainly inherited from the watershed but there exist marked differences between the accumulated sediments and their parent materials. These differences mainly come from the selective erosion of fine-grained particles and the extreme climatic conditions which enhance complex transformations of mineralogical and chemical nature. Compared with the parental soils, the reservoir sediments show the following differences: (1) enrichment in fine-grained and less dense inorganic particles, (2) aggradative mineralogical transformations, including enrichment in clay minerals with higher cationic adsorption and exchange capacity, (3) degradation of the crystalline structure of Fe- and Al-oxides (goethite, gibbsite), (4) increase in easily leached elements (Mg, Ca, P, K, Na) and decrease in chemically less mobile elements (Si, Fe) and (5) higher contents of organic carbon, nitrogen, and soluble forms of P and K, mainly concentrated in the clay fraction. These transformations are extremely important in the nutrients cycle, denoting that sediments represent an efficient sink for nutrients from the over-erosion of soils. Mineral and organic compounds can permanently or temporarily sequester these nutrients, recycling them and enhancing their availability through the slow release of components from relatively loose crystal structures. These processes can easily explain the enrichment in soluble and exchangeable forms of elements such as P, K, Ca or Mg. This study conclude that the particles recycling in a large tropical dam reservoir which receives high fluxes of allochthonous nutrients, has an important role in the good quality of sediments for agricultural use and in the profitable use of this technology to recover depleted soils in remediation projects in regions near large hydroelectric plants.

Extinction debt on reservoir land-bridge islands

Large dams cause extensive inundation of habitats, with remaining terrestrial habitat confined to highly fragmented archipelagos of land-bridge islands comprised of former hilltops. Isolation of biological communities on reservoir islands induces local extinctions and degradation of remnant communities. “Good practice” dam development guidelines propose using reservoir islands for species conservation, mitigating some of the detrimental impacts associated with flooding terrestrial habitats. The degree of species retention on islands in the long-term, and hence, whether they are effective for conservation is currently unknown. Here, we quantitatively review species' responses to isolation on reservoir islands. We specifically investigate island species richness in comparison with neighbouring continuous habitat, and relationships between island species richness and island area, isolation time, and distance to mainland and to other islands. Species' responses to isolation on reservoir islands have been investigated in only 15 of the >58,000 large-dam reservoirs (dam height >15m) operating globally. Research predominantly originates from wet tropical forest habitats and focuses on mammals, with species richness being the most widely-reported ecological metric. Terrestrial taxa are, overall, negatively impacted by isolation on reservoir islands. Reservoir island species richness declines with isolation time, and although the rate of loss is slower on larger islands, all islands exhibit depauperate species richness <100years after isolation, compared to continuous mainland habitats. Such a pattern of sustained and delayed species loss following large-scale habitat disturbance is indicative of an extinction debt existing for reservoir island species: this pattern is evident across all taxonomic groups and dams studied. Thus, reservoir islands cannot reliably be used for species conservation as part of impact mitigation measures, and should instead be included in area calculations for land impacted by dam creation. Environmental licensing assessments as a precondition for future dam development should explicitly consider the long-term fate of island communities when assessing biodiversity loss vs energy output.

Transformative Consequences of Garrison Dam: Land, People, and the Practice of Archaeology

Transformative Consequences of Garrison DamLand, People, and the Practice of Archaeology Lotte E. Govaerts (bio) Key Words Missouri River, North Dakota, population displacement, River Basin Surveys, Sacagawea, Three Affiliated Tribes of the Fort Berthold Reservation Dam building is a major human endeavor. The World Register of Dams currently lists 58,266 “large dams,” defined as those measuring over fifteen meters in height.1 Smaller dams are not included in the register, but in aggregate, small reservoirs are estimated to have three or four times as much total surface area as large dam reservoirs. Global estimates for reservoir area vary, ranging between 400,000 km2 (estimated in 1993) and 1,500,000 km2 (estimated in 2000).2 The United States, with 9,265 large dams, is the second most dammed country in the world (After China’s 23,842 and followed by India’s 5,102).3 Including smaller dams, the total for the United States adds up to some 75,000 dams. All US watersheds larger than 2,000 square kilometers have one or more dams altering their flow.4 Garrison Dam in North Dakota (Fig. 1) is one of many large dams built in the United States during the mid-twentieth century. This essay examines the history and impact of Garrison Dam and its reservoir, Lake Sakakawea. The focus is historical issues related to dam construction, as well as the environmental and social impacts of large dams in general and of Garrison Dam in particular. Most importantly, included is an investigation as to how archaeology in North America was influenced by the construction of Garrison Dam and the other large dams on the Upper Missouri River. The Construction of Garrison Dam—A Federal Affair Garrison Dam, built between 1946 and 1952, is an example of a modern dam. Dam building, irrigation, and hydropower have been practiced for thousands of years. The extensively researched Jawa dams in present-day Jordan date to approximately 3000 bce and are often [End Page 281] cited as the oldest known dams, although archaeological evidence of irrigation canals in the foothills of the Zagros Mountains in Iran is potentially associated with even earlier dam-building activities.5 Structures built to divert rivers for irrigation or water storage existed throughout the Middle East and Egypt in the second and third millennium bce, and spread throughout the Mediterranean and Europe during the Greek and Roman periods.6 Technologies for converting flowing water into mechanical energy date back almost equally far.7 Click for larger view View full resolution Fig 1. Map of Garrison Dam and Lake Sakakawea on the Missouri River in North Dakota (based on data from Google). Archaeological evidence of dam building also exists in the Far East as well as the Americas.8 Dams in the Americas long preceded the arrival of Europeans. The Chimu Empire of the Andean highlands (in present-day Peru) constructed dams, as did the Maya in the northern part of the Yucatan Peninsula.9 The Hohokam constructed elaborate irrigation networks in what is now the state of Arizona.10 Modern-era dam construction proliferated with the industrial revolution as bigger industries needed more water power, and growing urban areas needed a larger water supply. Dams grew ever larger, but until the twentieth century there was little scientific understanding of dam engineering and thus there were frequent collapses and other failures.11 In the nineteenth-century United States, there were many dams built for municipal use, industrial power, and irrigation by local governments or collectives of water users. [End Page 282] This changed in the twentieth century, when the federal government became the dominant dam builder.12 Two agencies were primarily in charge of building the large dams of the twentieth century: the US Army Corps of Engineers and the Bureau of Reclamation. The US Army Corps of Engineers was established shortly After US independence. From the beginning there was a push for the Corps to do “works of a civil nature” in addition to military construction. In 1816, mobilization studies based on data from the War of 1812 concluded that national defense would benefit from improved rivers, harbors, and transportation systems, allowing for faster troop movement and logistics...

Numerical simulation of earthquake excited dam-reservoirs with irregular geometries using an immersed boundary method

In this work, a ghost-cell immersed boundary method is proposed for the hydrodynamic response of earthquake excited dam-reservoirs. The numerical method employs a second order accurate two-step projection algorithm including compressibility effects in pressure field due to earthquake. The effects of reservoir bottom absorption are treated by introducing damping terms into the momentum equations. Hydrodynamic response of earthquake excited dam with a sloping face is simulated to demonstrate the accuracy of the present numerical method. Numerical results compared with previous numerical and analytical solutions show that the present immersed boundary method can accurately compute the hydrodynamic forces on inclined and curved dam faces including the effects of water compressibility and reservoir bottom absorption for the possibility of resonance. The proposed numerical method was shown to have significant advantages in computational time and memory usage for the hydrodynamic simulation of large dam-reservoirs with arbitrary geometries. Hydrodynamic forces on a double curvature arch dam subjected to real earthquake induced ground motion are also simulated to demonstrate the capability of the method.