Dam Height Research Articles

Investigation of the Effective Numerical Model for Seismic Response Analysis of Concrete-Faced Rockfill Dam on Deep Overburden

The construction of high rockfill dams on deep overburden in seismically active regions poses significant challenges. Currently, there are no standardized guidelines for defining the computational domain range in seismic analysis, necessitating the establishment of a universally applicable computational domain range that optimizes the balance between computational accuracy and efficiency. This has critical engineering implications for the seismic analysis of rockfill dams on deep overburden. This study employed the seismic wave input method to consider the dynamic interaction between the dam, overburden, and infinite domain. A systematic investigation was conducted on a concrete-faced rockfill dam (CFRD) constructed on deep overburden, considering the influences of overburden thickness, dam height, overburden properties, soil layer configuration, ground motion intensity, and the frequency content of the seismic waves. The acceleration response and seismic deformation of the dam were analyzed. Subsequently, the computational domain range corresponding to various levels of acceptable engineering precision was established. The results indicated that the lateral boundary length should extend a minimum distance equal to the sum of 3 times the overburden depth and 1.2 times the maximum dam height. Additionally, the depth below the overburden–bedrock interface should extend at least 1.2 times the maximum dam height. This study provides a crucial foundation for determining the optimal computational domain range in the seismic analysis of rockfill dams constructed on deep overburden.

Tailings storage facilities in China: historical failure incidents, existing status, and database-driven quantitative risk assessment

Tailings storage facility (TSF) failures in China have historically resulted in downstream consequences, including fatalities, economic harm, and environmental contamination. However, the nation-wide documentation on existing TSFs is incomplete, and the magnitude-frequency statistics of the failures are poorly quantified. These gaps have impeded ongoing efforts of risk assessment and mitigation. This study collates and analyzes new databases on historical TSF failures and existing TSFs in China. We report 143 TSF failures in China over the period 1957-2023, which exceeds the number (∼20) reported in previous studies. Magnitude-frequency statistics indicate that the mean return period for TSF failures in China with at least 10 fatalities is ∼5 years, while for those with released volumes >1 million m3 is ∼16 years. Our review confirms that there are at least 14,217 existing TSFs in China; therefore, the cumulative failure rate of TSFs in China is estimated to be ∼1%. We supply a database of 1,853 TSFs that lists the statistics such as storage volume and dam height. Using these datasets along with downstream demographic statistics, we undertake a regional risk assessment for Jilin Province, which identifies 11 TSFs with intolerable risks. Among these, the most critical TSF poses a potential loss of 175 lives. Our findings provide the most comprehensive picture of TSFs in China to date. We anticipate that this study will advance tailings disclosure practices in China and support screening-level risk assessments by provincial regulators to help prioritize community engagement and risk mitigation efforts.

Analysis on dynamic characteristics of dam material and seismic response of embankment dam in Longyang Reservoir

PurposeThe geological conditions of Longyang Reservoir are complex and it is located in strong earthquake area. In order to determine its seismic characteristics, the seismic response and residual deformation of embankment dam should be studied to provide calculation basis for dam design and construction.Design/methodology/approachBased on the geological survey data of Longyang Reservoir, the dam filling materials are tested by dynamic deformation tests, and the equivalent linear constitutive model parameters of the filling materials are obtained. Based on Duncan-Chang E-B model, the stress state of embankment dam in Longyang Reservoir before earthquake is calculated, and the dynamic response and earthquake residual deformation of embankment dam in Longyang Reservoir under earthquake condition are calculated by using equivalent linear model and Shen Zhu-jiang’s residual deformation model.FindingsThe results show that with the increase of dynamic shear strain, the dynamic shear modulus decreases and the damping ratio increases. The scatter plot between dynamic shear modulus and dynamic shear strain, and the scatter plot between damping ratio and dynamic shear strain under different confining pressures show strips. The calculation results shows that the acceleration of embankment dam in Longyang Reservoir increases with the increase of dam height, and the acceleration distribution has obvious amplification effect. Combined with the maximum dynamic shear strain during the earthquake and the state before the earthquake, the maximum vertical residual deformation of embankment dam in Longyang Reservoir is 2.98 cm which occurs at the top of the dam, calculated by the Shen Zhu-jiang’s residual deformation model.Originality/value Finite element calculation model parameters of embankment dam are obtained by dynamic triaxial tests. Seismic dynamic responses and residual deformation of embankment dam are analyzed. With the increase of dam height, the acceleration distribution shows an obvious amplification effect. The vertical displacement of embankment dam is larger along the dam axis and decreases in the upstream and downstream direction. The maximum horizontal displacement of embankment dam occurs in the middle of upstream and downstream dam slopes.Highlights(1)Finite element calculation model parameters of embankment dam are obtained by dynamic triaxial tests.(2)Seismic dynamic responses and residual deformation of embankment dam are analyzed.(3)With the increase of dam height, the acceleration distribution shows an obvious amplification effect.(4)The vertical displacement of embankment dam is larger along the dam axis and decreases in the upstream and downstream direction.(5)The maximum horizontal displacement of embankment dam occurs in the middle of upstream and downstream dam slopes.

Study on the Effect of Liquefiable Overburden Foundations of Rockfill Dams Based on a Pore Pressure Model

China’s southwestern region boasts abundant hydropower resources. However, the area is prone to frequent strong earthquakes. The areas surrounding dam sites typically have deep overburden, and the liquefaction of saturated sand foundations by earthquakes poses significant safety risks to the construction of high dams in the southwest. The effects of liquefaction and reinforcing measures on the foundations of rockfill dams on liquefiable overburden under seismic action are currently the subject of somewhat unsystematic investigations. The paper utilizes the total stress and effective stress methods, based on the equivalent linear model, to perform numerical simulations on the overburden foundations of rockfill dams. The study explores how factors such as dam height, overburden thickness, liquefiable layer depth, liquefiable layer thickness, ground motion intensity, and seismic wave characteristics affect the liquefaction of the overburden foundations. Additionally, it examines how rockfill dams impact the dynamic response, considering the liquefaction effects in the overburden. The results show that although the total stress method, which ignores the cumulative evolution of pore pressure during liquefaction, can reveal the basic response trend of the dam, its results in predicting the acceleration response are significantly biased compared to those of the effective stress method, which comprehensively considers the cumulative changes in liquefaction pore pressure. Specifically, when the effect of soil liquefaction is considered, the predicted acceleration response is reduced compared to that when liquefaction is not considered, with the reduction ranging from 4% to 30%; with increases in the thickness and burial depth of the liquefiable layer, the effective stress method considering liquefaction significantly reduces the predicted peak acceleration; the effect of liquefiable soil on the attenuation of the speed response is more sensitive to the low-frequency portion of the seismic wave. The study’s findings are a significant source of reference for the planning and building of rockfill dams on liquefiable overburden.

Experimental study on the stability of noncohesive landslide dams based on seepage effect

Landslide dams composed of unconsolidated, noncohesive soil are easily affected by seepage. As seepage develops, the dam's characteristics change dynamically, indirectly affecting its stability. However, previous studies on dam failure have mostly assumed that the dam characteristics remain constant before failure, often overlooking these changes and their effects on stability. In this study, 48 sets of flume experiments were conducted to quantify the impact of seepage under varying upstream inflow rates, dam heights, downstream slope angles, and particle size distributions. During the storage phase, the rise rate of the water level is closely linked to the seepage's diversion capacity. The diversion rate of inflow reached as high as 0.747 in this study, but decreased to 0.230 as inflow increased. Furthermore, changes in the internal stress distribution within the dam, driven by seepage, contributed to dam settlement and the sliding of the downstream slope. Notably, dam settlement exhibited both non-uniform spatial distribution and temporal stage development. The maximum settlement ratio between the point in the upstream breach and the point in the downstream breach reached as high as 2.79. Regarding the soil changes within the dam, after the seepage channel became connected, the primary soil loss involved silt particles ranging from 10 to 20 μm in size. This result reflects the increasing non-uniformity within the dam caused by seepage. Finally, Considering the changes in dam characteristics under the influence of seepage, in this study, a logistic regression model was established to assess dam stability. Overall, this study enhances the understanding of how seepage affects dam stability by examining various dam properties and presenting a model for stability assessment.

A novel finite element limit equilibrium method and its application in instability analysis for 3-D high core rockfill dams

The safe operation of high rockfill dams is an important issue related to human life and property safety. However, the stability analysis of high core rockfill dams with complex spatial morphology is mostly confined to two-dimensional, and appropriate stability analysis methods are scarce. Therefore, it is necessary to develop the three-dimensional stability analysis method for high core rockfill dams and study the spatial stability mechanism after impoundment. Firstly, a finite element limit equilibrium framework suitable for stability analysis of high rockfill dams is introduced, and the horn-shaped three-dimensional failure mechanism is presented for optimization. Then, according to the statistical results of the actual core rockfill dam above 100 m, 15 high dam models with actual Duncan-Chang parameters between 100 m and 300 m are established to study the three-dimensional instability mechanism. Meanwhile, grey relation analysis (GRA) is used for quantitative analysis of stability sensitive factors. Finally, the stability analysis of the Quxue core rockfill dam (173.2 m) was completed within the established stability framework. The results show that the combined failure mechanism with the horn-shaped is suitable for dam stability analysis, and with the increase of height and slope ratio of dam, the most dangerous sliding surface evolves to shallow layer. In addition, GRA results show that slope ratio is the most sensitive parameter compared to dam height and material parameters. The practical engineering stability results of Quxue show that the research results can provide a reliable reference for the stability of the high core rockfill dam.

Assessing controls on sedimentation rates and sediment organic carbon accretion in beaver ponds

Beaver dams trap sediment, promote channel-floodplain connectivity, modify biogeochemical cycling and organic carbon (OC) storage, and influence geomorphic form. Beaver-related sediment accumulation has been investigated at longer timescales (e.g., > 1000 years) and shorter timescales (< 10 years), but we lack information on sedimentation and sediment-associated OC accretion rates over multiple decades in relatively persistent beaver ponds (10–100 years old). We coupled field surveys of 45 beaver ponds with historical aerial imagery and radiometric dating with 7Be, 210Pb, and 14C to calculate sedimentation rates, mean sediment depth, and sediment OC content at two study sites in the southern Rocky Mountains, USA. Sedimentation rates in beaver ponds (median = 5.7 cm yr−1, mean = 11.6 cm yr−1) decreased with pond age. Incised, single threaded reaches had greater variability in mean sediment depth compared to less incised reaches. In less incised reaches, mean sediment depth and beaver dam height increased with pond age, indicating more stable dams and depositional environments. Sediment OC content within beaver ponds (median = 0.8 %, mean = 1.7 %) increased with finer sediment grain size distributions. Sediment OC accretion rates in ponds ranged between 0.13 and 23 Mg C ha −1 per year. We used Monte Carlo simulations to estimate it would take ∼100 years or more of uninhibited beaver activity for deposition to laterally reconnect adjacent terraces in the incised study reaches, a common objective within many stream restoration projects. Our findings show that beaver ponds in complex, multi-threaded reaches better retain fine sediment over longer timescales, highlighting the need to incorporate geomorphic context when considering whether beaver can help restore incised river channels and floodplain connectivity, retain fine sediment, and store OC on the landscape.

The effects of flow extremes on native and non‐native stream fishes in Puerto Rico

Abstract Globally, freshwater fishes are among the taxa most vulnerable to climate change but are generally understudied in tropical island ecosystems where climate change is predicted to alter the intensity, frequency and duration of extreme flow events. These changes may impact stream ecosystems and native and non‐native biota in complex ways. We compiled an extensive dataset of fish assemblages collected at 119 sites across the Caribbean island of Puerto Rico from 2005 to 2015. We coupled these data with stream flow indices and dam height to understand associations between flow and fish assemblage structure. Sixteen percent of sites contained exclusively non‐native species, 34% contained exclusively native species, and 50% contained native and non‐native species. We built generalised linear models and conducted all subsets model selection to identify extreme flow variables explaining variation in native and non‐native species richness and biomass. We also built models to determine the combined effects of extreme flows and the presence of non‐native species on native species richness and biomass. Extreme flows and dam height were important in explaining variations in native and non‐native species richness and biomass. Model averages showed native biomass decreased by 0.42 kg/ha with a 1‐m increase in dam height, by 0.05 kg/ha with 1 cm/s increase in maximum mean daily high flow and by 3.45 kg/ha with each additional day increase in maximum high flow duration, and increased by 2.06 kg/ha with each additional day increase in mean high flow duration. Model averages predicted that non‐native biomass increased by 1.32 kg/ha with a 1‐m increase in dam height and by 0.01 kg/ha with each additional day increase in mean high flow duration, and decreased by 0.36 kg/ha with each additional day increase in maximum high flow duration. Model averages also predicted an increase in native and non‐native biomass of 0.71 gage and 0.06 kg/ha, respectively, with each additional day increase in maximum low flow duration. The combined effects of non‐native species presence and extreme flows changed the relationship between maximum high and low flow durations and native biomass. Model averages showed that native biomass increased by 1.83 kg/ha with each additional day increase in maximum high flow duration and decreased by 2.52 kg/ha with each additional day increase in maximum low flow duration when non‐native species were present. Native fishes may be able to better cope with longer maximum durations of low flows than expected when non‐native fishes are absent. In mixed fish assemblages, extended maximum durations of high flows may act as a control of non‐native species and dampen their negative effect on native species, but longer maximum durations of low flows may heighten the negative effects of non‐native fishes. Our results are informative for tropical island ecosystems globally and can guide the management and conservation of native fishes, particularly when faced with the dual threats of climate change and non‐native species. Managers may consider increasing efforts to conserve native fishes in Caribbean rivers by maintaining connectivity and habitat complexity while preventing non‐native species introductions.

Research on Failure Modes and Causes of 100-m-High Core Wall Rockfill Dams

Rockfill dams are the most competitive type of dam in complex geological environments. Identifying the failure modes and causes in high dams over 100 m is critical for better guiding high dam designs and implementing safety prevention and control measures. To this end, this paper investigated numerous cases of earth–rock dam breaches and failure modes in rockfill dams globally, with a particular focus on dams over 100 m in height, encompassing all such dams in China. The study categorized dam failure modes based on whether the dams were built before or after 1980. It also examined the causes of dam failures in terms of dam height, foundation characteristics and thickness, and failure time. Additionally, the paper analyzed a rockfill dam in China, with a height of 136 m and over ten years of operation, as a case study. We analyzed the spatial and temporal characteristics and causes of failures, such as dam crest cracking, high-level seepage, and gallery cracking, using the design situation, monitoring data, and numerical simulation. The paper also addressed issues related to dam design and foundation treatment, providing recommendations for improvement. The study indicated that the overall risk of total failure for dams over 100 m is already low. However, longitudinal cracks on the dam crest, core wall seepage, hydraulic splitting, and seepage damage to the dam foundation are primary issues in the current high core wall rockfill dams. These issues are mainly caused by uneven structural deformation of the dam and its foundation. A reasonable design of rockfill materials and foundations can mitigate these failures.

Variable-density solute transport in unconfined coastal aquifers with a subsurface dam

Recently, the influence of subsurface dams on solute transport in coastal aquifers has become a hot research topic. Although many studies have been conducted, the combined effects of subsurface dam and tides on variable-density solute transport remain unclear, and this study aimed to fill this research gap. In the current study, a numerical model representing a 2-D cross-shore coastal aquifer was established. The model simulated cases with and without a subsurface dam, and sensitivity analysis cases with different height and location of the subsurface dam and solute concentration. The results show that a subsurface dam blocks a portion of the solute plume, which can only be discharged by dilution at the edges, thereby altering its discharge pattern and reducing their discharge rate. The addition of a subsurface dam may either prolong or shorten the residence time of solute,depending on the location rather than the height of the subsurface dam. In particular, a more landward subsurface dam would significantly increase the residence time; sensitivity analysis demonstrates that both the landward shift and the height increase of the subsurface dam contribute to a heightened ratio of dynamic mass distribution for the solute plume within the freshwater and saltwater zones of the aquifer, with maximum changes in mass distribution ratios of 87.22% and 300%, respectively. Also, these factors cause the solute to migrate both seaward and landward, respectively, across the primary outflow regions of the aquifer-ocean interface. Results from this study may provide theoretical guidance for the optimal design and environmental impact assessment of subsurface dams.

Theoretical model and parameter sensitivity analysis of concrete slab vibration in concrete-face rockfill dams during underwater nuclear explosions

Large reservoir dams, which are carriers of energy and resources, have historically been the main targets of military conflict and terrorist attacks. A concrete-face rockfill dam (CFRD) is a competitive hydraulic structure widely used in large-scale water conservancy projects. However, the vibration response and damping paths of CFRDs under the influence of underwater explosion shock waves remains insufficiently understood. In this study, we created a theoretical model of slab vibration with four-sided free boundaries using Cole’s formula and the motion differential equation of a slab on an elastic foundation. Furthermore, a global sensitivity analysis of the vibration model parameters on the slab displacement was performed based on the Kriging surrogate model and Sobol method. The results showed that the antiseepage slabs experienced a void phenomenon, resulting in overall instability. The explosive distance and normal stiffness of the slab had the greatest influence on the void displacement of the slab, whereas the dam height and concrete density had insignificant effect. Moreover, increasing the dam height of the CFRD did not increase the risk of slab voids during underwater explosions, which was not the case under strong seismic loads. Therefore, the key factors for active and passive defense against blast resistance in CFRDs were identified, which can provide theoretical support for the blast-resistant design and research on CFRDs. In this study, the reliability of the theoretical model was verified by establishing a numerical analysis model.

Theoretical and experimental studies on air-inflated rubber dam anchored on sidewall of the rigid base

A theoretical study was conducted to investigate the cross-sectional configurations and the tensile forces of an air-inflated rubber dam anchored on the sidewall of the rigid base. A series of large-scale model tests were conducted using rubber dam models with a cross-sectional perimeter of 1.0 m and a length of 8.5 m. The results obtained from the analytical solutions agree well with those obtained from model tests. It is found that there is an optimum height of the rubber dam, especially for larger anchor depth with the increase of the inflated air pressure. The smaller the anchoring depth the higher the optimum inflated air pressure. The contact length between the rubber dam and the rigid base gradually decreases with the increasing inflated air pressure. The greater the anchor depth, the faster the contact length decreases to zero. Generally, the tensile force linearly increases with the increase of the normalized air pressure and the decrease of the anchor depth.

Modern reservoirs with dam heights of tens and hundreds of meters above the river coastline with flooding of cities, villages, territories – this is a crime against humanity and nature. It is quite possible to eliminate floods.

Modern reservoirs with dam heights of tens and hundreds of meters above the river coastline with flooding of cities, villages, territories – this is a crime against humanity and nature. It is quite possible to eliminate floods.

The Spatial–Racial Patterns of U.S. Dam Removals Since 2010

Dam removal in the United States has grown exponentially, yet we do not know whether the pattern of such removals comports with principles of environmental justice. This exploratory study investigates the spatial pattern of dam removals across the United States to ascertain whether there were any geographic areas where the probability of removal was correlated with the racial or ethnic composition of the environs. We analyze dam removals since 2010 using national data on existing dams, removed dams, and demographics. We estimate multivariate probability models of dam removal stratified by census region and dam ownership to pinpoint contexts where significant spatial-racial patterns occur that cannot be attributed to dam characteristics. Our exploration reveals only a few such contexts. After controlling for dam purpose, construction type, age, and height, the probability of a dam being removed since 2010 is positively associated with the proportion of nearby White residents for dams owned by local or state governments in the South. The probability of removal is negatively associated with the proportion of nearby White residents for dams owned privately or by state or local governments in the West. Future case studies should probe these contexts of clear spatial–racial patterns from an environmental justice perspective.

Distribution and Stabilization Mechanisms of Stable Landslide Dams

Landslide dams, especially stable landslide dams, have been recognised as important contributors to regional geomorphological evolution. The eastern edge of the Tibetan Plateau provides good conditions for the formation of stable landslide dams. To identify stable landslide dams on the eastern margin of the Tibetan Plateau, the Google Earth Engine (GEE) was first used to map water surfaces in the study area. Then, stable landslide dams were identified using high-precision remote sensing images provided by Google Earth. A field investigation and a sampling of typical stable landslide dams were also adopted to characterise the landslide dams. The results show that 101 stable landslide dams are present in the study area, covering an area of 27.75 × 104 km2. There are four types of stable landslide dams, as follows: (1) landslides, (2) rock avalanches, (3) moraines, and (4) debris flows. The morphological parameters of a dam, which include dam height, dam width, dam volume, and catchment area, can be fitted with different relationship curves, with respect to the number of landslide dams. The source areas of landslide dams are generally located in the upper-middle and upper sections of adjacent mountains. The stability of a landslide dam is mainly controlled by the structure of the dam and the relationship between the dam volume and catchment area. Structurally, large rocks with large particle sizes are difficult to activate using river water and the large gaps between the rocks provide sufficient channels for the flow of river water. In regard to the relationship between the dam volume and catchment area, a river with a small catchment area in the study area is commonly blocked by a large dam volume. This study provides a unique opportunity to study the spatial distribution and clarify the factors influencing the stability of stable landslide dams.

Research on the slip deformation characteristics and improvement measures of concrete-faced rockfill dams on dam foundations with large dip angles

The pumped storage power station (PSPS) is an important measure to achieve the strategic goal of “dual carbon”. As one of the preferred types for the upper reservoir dams of PSPSs, the concrete-faced rockfill dam (CFRD) often has a dam foundation on a steep transverse slop and is prone to produce slip deformation along the slope, resulting in poor anti-sliding stability of the dam slope. It is dangerous for the operation safety of PSPSs. Therefore, the slip deformation of CFRDs on dam foundations with large dip angles is investigated. The mechanism for the initiation of slip deformation is revealed. The design measures of physical mechanic and geometric structure are proposed to reduce slip deformation. The results show that the larger sliding forces and smaller anti-sliding forces are the fundamental reasons that CFRDs on dam foundations with large dip angles are prone to produce slip deformation. The larger the dip angle of the dam foundation, the larger the slip deformation of the dam body and face slab, and the smaller the safety factor of the dam slope. When the dip angle of the dam foundation is greater than 15°, the safety factor of the dam slope is less than the minimum value of 1.5 required by codes. The addition of pressure slopes can effectively reduce the slip deformation of the dam body or face slab and significantly improve the anti-sliding stability of the dam slope. When the height or width of the pressure slope platform is greater and the cohesion or internal friction angle of the pressure slope is larger, the slip deformations of the dam body and face slab are smaller, and the safety factor of the dam slope is greater. It is recommended that the height and width of the pressure slope platform be 1/2 times the maximum height of the main dam, and the density (cohesion and internal friction angle) of the pressure slope be equivalent to that of the main dam’s rockfill material. The research results can provide theoretical and technical support for the design and construction of CFRDs for the upper reservoir of PSPSs.

Spatiotemporal clustering of dam settlement monitoring using instrumentation data (case study: Eyvashan Earth Dam)

The integrity of monitoring data is important for studying the amount and location of deformation in earth dams. In this research, the meeting of the Eyvashan Earth Dam was analyzed using the results of precision instruments over a period of eight years during three periods of construction, first impoundment, and exploitation. To verify the accuracy of the results, the numerical model of the largest section of the dam was constructed with Plaxis software and analyzed according to the Mohr–Coulomb behavior model. The results showed that since the beginning of construction, the occurrence of settlements in the core of the dam has been increasing, and with the passage of time, settlements reach a constant value in the operation phase. The maximum settlement of the dam core at the end of the construction stage was 809 mm, which was equal to 1.2% of the dam height in the middle level. Additionally, an approach based on spatiotemporal clustering has been presented to improve the interpretability of the settlement behavior of earth dams. Clustering analysis of spatiotemporal data is used as a measure to determine the similarity of settlements and to select relevant data. Therefore, k-means clustering algorithms and two-step clustering were used to determine the displacement of earth dams. By comparing the correlation results, the proposed method of detecting settlement areas using a spatiotemporal clustering model can be considered a reliable method for monitoring the settlement of earth dams.

High modulus partition deformation control of high concrete face rockfill dam

Concrete face rockfill dams, preferred for their adaptability in unloading and soft rock foundations, encounter significant deformation control challenges at increased heights. This study analyses the stress and strain of five Chinese dams, ranging from 179.5 m to 233.5 m, demonstrating improved structural responses by implementing high-modulus zones in the rockfill and concrete embedment. The findings reveal a direct relationship between rockfill settlement, concrete face slab deflection, and dam height. Incorporating a high-modulus zone and concrete embedment resulted in reduced rockfill settlement by 15% and 5.8%, concrete face slab deflection by 17% and 41.9%, and joint deformation by 10%–20% and 21.2%, respectively. This study is expected to support the deformation control of high-concrete-face rockfill dams.

Allocation of reservoirs sites for runoff management towards sustainable water resources: Case study of Harirud River Basin, Afghanistan

The intensification of drought conditions in arid and semi-arid regions coupled with the growing population increased water demands (domestic, and irrigation). It signifies the importance of addressing the pressing need for sustainable water resource management. Seventeen criteria spanning topographical, hydrological, geological, environmental, and socio-economic categories, were used for dam site suitability analysis for Harirud River Basin, Afghanistan. Weighted Linear Combination (WLC) model and Geographic Information System (GIS) were employed to perform multi-criteria analysis (MCA) method. The results revealed that the final suitability map exposed 12.31 % highly suitable, 21.0 % moderately suitable, and 66.68 % non-suitable sites, totaling 125.8 km, 214.6 km, and 681.4 km, respectively. Segmentation accuracy assessment was utilized to evaluate the existing dam’s accuracies. The study revealed that accuracies of 84.65 % for the Salma Dam and 88.08 % for the Pashdan Dam were achieved, respectively. Six new dams, along with the existing two, formed the series of eight dams. The dam series were optimized for the total annual runoff of (1,600,000,000 m3), and the final dam heights were determined as follows: 107.5 m, 42 m, 100 m, 23.9 m, 30 m, 18 m, 23.44 m, and 22.65 m for dams (1 to 8), respectively. The study underscores the methodology's superiority in site suitability analysis and runoff optimization, while recommending future focus on observational data and higher-resolution digital elevation model (DEM) files for enhanced precision, environmental impact assessment, climate change considerations, social and economic implications, improved data resolution, and transboundary cooperation.

Assessment of stability of earth dams based on construction pace by fuzzy inference logic

This study aims to evaluate the earth dam stability fuzzy model based on the pace of construction by way of influential parameters, including the dam construction time (embankment consolidation time) in the stability analysis of earth dams. A fuzzy inference system based on the Sugeno inference engine was developed, and 620 if-then rules in plane strain and axial symmetry (Plaxis) were used to train the fuzzy system. The input parameters included the dam height, crest width, dam slope, cohesion, friction angle, elasticity modulus, Poisson’s ratio, unsaturated unit weight, consolidation (construction) time and permeability coefficient, with the factor of safety output. To develop the fuzzy inference system, a triangular membership function was employed, calculating the influential parameters over five periods in Matrix laboratory (Matlab) software. The fuzzy model results were compared with the results of numerical Plaxis and fast Lagrangian analysis of continua models. High coefficients of determination (R2) suggest good agreement between the fuzzy and numerical models, and it can be assumed that the proposed fuzzy model is efficient and effective for the stability analysis, and hence assessment of factors of safety, of earth dams.