Dez Dam Research Articles

Investigating hybrid deep learning models and meta-heuristic algorithms in predicting evaporation from a reservoir: a case study of Dez dam

Investigating hybrid deep learning models and meta-heuristic algorithms in predicting evaporation from a reservoir: a case study of Dez dam

Development of multiphase solver for the modeling of turbidity currents (the case study of Dez Dam)

Dams in semi-arid regions, like Iran's Dez dam, are losing their capacity by sedimentation. Settling sediments reduces clear water, and hydropower plants' efficiency. Reservoir sedimentation relies on turbidity currents (TC). TC head velocity, and sediment content both affect particle tracking, and the removal from reservoirs. To comprehend the TC properties of Dez dam reservoir, large-scale TC modeling is required. To represent large-scale TC, a novel solver is developed. This solver couples a modified OpenFOAM® interFoam solver with the particle concentration transport equation. Two experimental tests, and Dez dam field data were verified and calibrated. The novel solution modeled these instances utilizing a two-dimensional vertical model (width averaged) with RANS turbulence closure, despite the fact that the Dez dam reservoir has a considerable size for numerical modeling. The solver simulated four Dez Dam reservoir scenarios with different water levels. Consequently, when the inlet water depth rose four times, the TC head velocity, and distance traveled by TC doubled. TC in Dez dam is a supercritical flow with the interface instabilities based on its local Richardson number, and gradient Richardson number. Furthermore, Kelvin-Helmholtz instabilities and recirculation vortex combine clear water with TC to reduce the particle concentration.

Tracing of petroleum products in groundwater (upstream of Dez watershed to Dez dam) in order to develop a new method of risk assessment

Tracing of petroleum products in groundwater (upstream of Dez watershed to Dez dam) in order to develop a new method of risk assessment

An integrated fuzzy optimization and simulation method for optimal quality-quantity operation of a reservoir-river system

Abstract In this study, a novel optimization-simulation dynamic approach was developed for optimal water operation of reservoir-river systems to improve the water quality and supply the water demands along a river. To this purpose, the WEAP-QUAL2 K linked model was developed to simulate water quality and quantity, which is dynamically coupled to a fuzzy multi-objective imperialist competition algorithm (FMOICA). The approach's applicability is demonstrated through the case study of the Dez reservoir river in Iran. The simulation and optimization period used was six years (October 2019-September 2025). Stochastic models (SARIMA(1,0,1)(1,1,1)) were used to forecast inflow into the Dez dam reservoir for the simulation period. Given that in the verification stage of the QUAL2 K and WEAP model it was concluded that the model has high accuracy in simulating the parameters of water quality and quantity, two scenarios were considered: the first scenario was used for dynamic coupling of the quantity-quality model (reference scenario), and the second was the fuzzy optimization of a linked model (optimal scenario). The results show that average water supply reliability increased from 86.13% in the reference scenario to 95.76% in the optimal scenario. Also, under the optimal scenario, the river water quality improves. It was also found that environmental flow rate demands of the river are fully supplied in different months.

Improving the estimation of sedimentation in multi-purpose dam reservoirs, considering hydrography and time scale classification of sediment rating curve (case study: Dez Dam)

Improving the estimation of sedimentation in multi-purpose dam reservoirs, considering hydrography and time scale classification of sediment rating curve (case study: Dez Dam)

Dez Dam Rehabilitation Project Role in Flood Damage Reduction

As a result of climate change, extreme precipitation events from mid-March to April 2019 in southwest Iran generated catastrophic floods taken 78 lives and left $4.1 billion financial damages. The extent of damages could have been even worse without the existence of upstream flood control dams including Dez dam. Dez Dam is the only large dam in its basin which play a significant role in flood control. A multi-purpose rehabilitation project including new power intakes, flushing tunnels and dam heightening with required investment of $350 million is defined in this dam to compensate reservoir live volume losses through 57 years of sedimentation. In this paper, the effect of dam heightening and the flushing tunnels will be evaluated by their roles in flood damage reduction. Assuming that the actual magnitude of a flood cannot be predicted beforehand, a flexible multi-stage routing method considering operator judgment during flood operations is proposed to produce an optimized flood routing policy. The related operation rule is derived for existing and rehabilitated dam and the expected annual damage (EAD) compared in both conditions. The results show that the dam heightening could be considered as an effective way to improve the dam role in flood damage reduction.

Optimal operation of single and multi-reservoir systems via hybrid shuffled grey wolf optimization algorithm (SGWO)

Abstract Reservoir operation is a key issue in the water resources system. In this paper, the Shuffled Grey Wolf Optimizer (SGWO), a hybrid optimization algorithm inspired by Shuffled Complex Evolution (SCE-UA) and Gray Wolf Optimizer (GWO) algorithms, is introduced. The main modification in the proposed algorithm is how it divides and shuffles the population to enhance the information exchange among the individuals. The performance of the SGWO algorithm is compared to famous evolutionary algorithms such as Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) in solving mathematical benchmark functions and multiple types of reservoir operation optimization problems with different scales. Two hypothetical 4 and 10-reservoir system, and the Dez dam in Iran as a single reservoir system were selected as the case study in this research. The capability of the algorithms was compared in terms of accuracy of derived optimum objective function values, convergence speed, and stability of answers in different implementations. The results showed that the SGWO can reach considerably better results (0.3% to 26% better than the closest rival algorithms) using significantly lower number of function evaluations. It also showed the lowest standard deviation among other algorithms for all problems, which indicated the high reliability of this algorithm.

Simulation and optimization of control system operation and surface water allocation based on system dynamics modeling

Abstract In the present study, the performance of Dez Reservoir, its regulatory and downstream diversion dams are studied using the system dynamics method (SD) in the Vensim software. In the first step, all the effective parameters with their relationship were identified and then the simulation was carried out considering the minimum and maximum reservoir volume and downstream demand over an eight-year period (2006–2013). After model validation, the statistical indices of correlation coefficient (R2), root mean square error (RMSE), and standard error (SE) for the reservoir volume were calculated as 0.99, 3.1690, and 0.18, respectively. The statistical indices for the regulatory dam were 0.98, 7.51, and 0.13, respectively. These statistical indices were 0.92, 4.71, and 0.37 for the diversion dam. The achieved results showed that the SD-simulated releases met downstream demands and the SD method has high accuracy in simulating the performance of the surface tank system. Moreover, for a better evaluation of the results of the SD model, the eight-year Dez dam releases were optimized using the particle swarm optimization (PSO) algorithm, and the required deficiency values were evaluated in both SD and PSO models. Results showed that SD provides more appropriate planning in meeting the downstream demands than PSO.

Developing a Web-based decision support system for reservoir flood management

Abstract Proper management of reservoirs in flood conditions minimizes flood damage and keeps the reservoir in a stable condition. This paper presents a Web-based decision support system of reservoir flood management (WDRFM) for reservoirs with gated spillways. WDRFM is capable of estimating the current situation of the reservoir and before the flood reaches the reservoir, provides the operator with suggestions to have optimal control over gates, using multistage simulation-optimization models to minimize flood damage downstream. Investigating the possibility of changing the dam's discharge gates, carrying out dam pre-release, and announcing relevant flood control warnings can all be performed by WDRFM, while allowing the operator to determine such observations and make final decisions on a time step basis. To assess the performance of WDRFM, 15 scenarios in four groups for flood management were defined on April 14, 2016 at Dez Dam, Iran. A comparison of one scenario with similar initial conditions with the occurrence of flood event has shown that a daily peak discharge shows 997 m3/s decrease from that recorded by the operator. The ability to examine different scenarios based on the conditions at any time in the WDRFM enables the decision-makers and operators to confront various circumstances.

Optimal utilization of DEZ dam reservoir considering drinking water demand by dynamic programming technique

Optimal utilization of DEZ dam reservoir considering drinking water demand by dynamic programming technique

A Multi-GCM Assessment of the Climate Change Impact on the Hydrology and Hydropower Potential of a Semi-Arid Basin (A Case Study of the Dez Dam Basin, Iran)

In this paper, the impact of climate change on the climate and discharge of the Dez Dam Basin and the hydropower potential of two hydropower plants (Bakhtiari and Dez) is investigated based on the downscaled outputs of six GCMs (General Circulation Models) and three SRES (Special Report on Emission Scenarios) scenarios for the early, mid and late 21st century. Projections of all the scenarios and GCMs revealed a significant rise in temperature (up to 4.9 °C) and slight to moderate variation in precipitation (up to 18%). Outputs of the HBV hydrologic model, enforced by projected datasets, show a reduction of the annual flow by 33% under the climate change condition. Further, analyzing the induced changes in the inflow and hydropower generation potential of the Bakhtiari and Dez dams showed that both inflow and hydropower generation is significantly affected by climate change. For the Bakhtiari dam, this indicates a consistent reduction of inflow (up to 27%) and electricity generation (up to 32%). While, in the Dez dam case, the inflow is projected to decrease (up to 22%) and the corresponding hydropower is expected to slightly increase (up to 3%). This contrasting result for the Dez dam is assessed based on its reservoir and hydropower plant capacity, as well as other factors such as the timely releases to meet different demands and flow regime changes under climate change. The results show that the Bakhtiari reservoir and power plant will not meet the design-capacity outputs under the climate change condition as its large capacity cannot be fully utilized; while there is room for the further development of the Dez power plant. Comparing the results of the applied GCMs showed high discrepancies among the outputs of different models.

Evaluation of different strategies for management of reservoir sedimentation in semi-arid regions: a case study (Dez Reservoir)

ABSTRACTEmamgholizadeh S, Bateni SM, Nielson JR. 2018. Evaluation of different strategies for management of reservoir sedimentation in semi-arid regions: a case study (Dez Reservoir). Lake Reserv Manage. 00:00–00.Reservoir sedimentation is a major concern, especially in arid and semi-arid areas, such as Iran. Dez Reservoir, with a primary storage capacity of 3315 × 106 m3, located on the Dez River, is an important dam in Iran that suffers from sedimentation problems. Large volumes of sediments are impounded every year in this reservoir, particularly during hyper-concentrated floods. The accumulation of sediments in the Dez Reservoir has negatively impacted its utilities, such as power generation, flood control, and water supply. In this study, several different strategies of sedimentation management were assessed, including watershed management, sluicing, flushing, density current venting, and bypass. The results show that sedimentation in the Dez Reservoir can be reduced by 11–15% by venting density currents, which entails discharging incoming density currents through irrigation gates before they get impounded in the reservoir. Sedimentation can be reduced by approximately 2% by pressure flushing, which would decrease sediment depositions near the power plant intake. By construction of a submerged dam 9 km upstream of Dez Dam Reservoir, the bypass technique can be used to release 10.8 × 106 m3 of sediments per year and discharge turbid flow during the flood season. Finally, implementing watershed management strategies in the Sezar catchment could reduce the inflowing sediment to Dez Reservoir by 15%. Dez Reservoir does not have sluice gates and, therefore, the free flushing and sluicing methods cannot be used as mitigation strategies.

Optimization of Multiple and Multipurpose Reservoir System Operations by Using Matrix Structure (Case Study: Karun and Dez Reservoir Dams).

Optimal operation of water resources in multiple and multipurpose reservoirs is very complicated. This is because of the number of dams, each dam’s location (Series and parallel), conflict in objectives and the stochastic nature of the inflow of water in the system. In this paper, performance optimization of the system of Karun and Dez reservoir dams have been studied and investigated with the purposes of hydroelectric energy generation and providing water demand in 6 dams. On the Karun River, 5 dams have been built in the series arrangements, and the Dez dam has been built parallel to those 5 dams. One of the main achievements in this research is the implementation of the structure of production of hydroelectric energy as a function of matrix in MATLAB software. The results show that the role of objective function structure for generating hydroelectric energy in weighting method algorithm is more important than water supply. Nonetheless by implementing ε- constraint method algorithm, we can both increase hydroelectric power generation and supply around 85% of agricultural and industrial demands.

Heterogeneous and anisotropic long-term concrete damage of the dez arch dam using thermal inverse analysis

AbsractIn this paper, an assumption used in the recent work of the author and his contributors considers the long-term concrete damage of the Dez arch dam as a homogeneous and isotropic process, was investigated in more detail and was adjusted. To this end, the vertical dam sections were divided into nine and six subsections along the thickness and height directions of the dam, respectively. In each subsection, a transversely isotropic damaged elastic constitutive law was considered for diagnostic analyses. Following the previous authors’ mentioned work, an optimization procedure (minimization of a certain error function) accompanied with an inverse thermal analysis was carried out. That analysis was performed within the framework of finite element (FE) method. Mentioned error function was defined as the sum of the squared residuals. Residuals were set as difference between nodal recorded displacements with inverse pendulums of the dam and the corresponding computed ones with the proposed model. Parameters considered as unknowns in the present inverse analysis, which have contributions in that above-mentioned error function, were the five independent elastic moduli presented in the formulation of the earlier mentioned transversely isotropic damaged elastic constitutive law: two Young’s moduli: one in the planes parallel to the up and down stream surfaces of the dam, called in-plane and the other in the perpendicular planes to those planes, named out-of-plane Young’s modulus; two Poisson’s ratios (in-plane and out-of-plane); and one shear modulus (out-of-plane). These parameters were identified performing numerous thermal inverse analyses. Obtained results revealed that the long-term damage of concrete of the Dez dam is a heterogeneous and anisotropic phenomenon because that the magnitude of the mentioned error function was obtained smaller than the corresponding value in the previous study which had been performed before based on the homogeneous and isotropic damage evolution assumption.

Estimate of time required for environmentally friendly flushing in Dez dam reservoir

Environmentally friendly flushing aims to send only the concentrations of the sediment that the environment can withstand. In this study, the time required for environmentally friendly flushing in Dez dam reservoir was estimated. For this purpose, the relationship between the concentration, duration, and scale of the severity of ill-effect for fish was considered. A study was conducted on Dez dam reservoir in Iran, where the average historical outflow from the dam, and the volume of sediment flushing was evaluated. According to this study, the dam is facing a serious sedimentation problem. Its dead volume is presumed to be quite full in the coming 10 years. Performing flushing operations through the three irrigation gates of the dam has received much more attention in recent years as compared to the past. The results from this study help us to determine the appropriate hydraulic conditions to decrease the negative environmental effects of Dez dam flushing operations on the downstream ecosystem.

Evaluation of river–aquifer interaction in the north part of Dezful–Andimeshk district, SW of Iran

The river and groundwater are significant components of hydrological cycle, and the interaction between these two water resources attracted a great attention recently. Over the years, several methods have been used for the study of the water exchanges between these resources. In this research, a combined approach including hydraulic head measurements, hydrochemistry, and water balance calculations is applied to the assessment of the river–aquifer interactions. The study area is located in the north part of the Dezful–Andimeshk district in the southwest of Iran. The Dez River is the major surface water body that interacts with groundwater in this area. The Dez dam has been constructed on this river in the northern part of the study area. In this study, a series of water measurements including river water stages and discharge monitoring at Dez dam site and Dezful hydrometric station, groundwater table measurement in the piezometric network, and chemical analysis of river and groundwater were carried out for the evaluation of river–aquifer interaction. In order to monitor river and groundwater in the study area, a monitoring network including a hydrometric station (near the Dezful city), 38 piezometers, and 23 water quality monitoring wells have been established by the Khuzestan Water and Power Authority (KWPA). Data of the monitoring network were used for the evaluation of temporal variation of river and groundwater interaction in this research. The discharge measurements of the Dez dam site and Dezful hydrometric station in a 47-year period (1964–2011) shows that the water volume is decreased between these two stations. In addition, examining the time series of river stage and groundwater fluctuations in the study area shows that the groundwater table and river water stage variations have similar patterns. This similar pattern is an observant indication of groundwater and surface water interactions that is confirmed by the interpretation of groundwater potentiometric map of the study area. Following these conclusions, the hydrochemical measurements also were used for the assessment of the Dez River and groundwater connectivity. The surveys showed the similar patterns in the temporal variation trends of chemical characteristics (especially chloride ion) of the Dez River and groundwater as a base for connectivity of these resources. For better assessment of the river–aquifer interaction, 69 groundwater samples were collected from the abstraction wells in August 2012. The physicochemical analysis results show the river influences the groundwater quality. That is, the amounts of electrical conductivity (EC), temperature, and anions such as chloride, sulfate, and nitrate show a notable decrease in river-adjacent wells. Finally, for the quantifying of river–aquifer exchange rate, a simple water balance was formulated. This water budget also confirmed the Dez River role in the hydrologic balance of the study area, and according to calculation, the water infiltration from the riverbed was estimated to be more than 8 % of the aquifer recharge. This research shows the losing nature of the Dez River and its influence on the underlying groundwater quality in the study area.

Выбор наилучшего рационального способа удаления осадочных веществ методом нечетких групп для плотины Дез

Выбор наилучшего рационального способа удаления осадочных веществ методом нечетких групп для плотины Дез

Evaluation of the thickness of turbidity currents entering Dez dam reservoir using the extended shallow water model (ESWM)

This research was developed for the evaluation of the thickness of turbidity currents coming into the reservoir of the Dez dam. In recent years, for the simulation of turbidity currents two types of mathematical models have been employed: (1) the extended shallow water model (ESWM), and (2) the suspension balance model. In this study, we used the ESWM to estimate the thickness of turbidity currents. A random study was carried out from January 2002 to July 2003 in the Dez dam reservoir. Dez dam in Iran is facing a serious sedimentation problem, and its dead volume will be quite full in the next 10 years, and now the inflow water in the hydropower conduit system is becoming turbid. Based on the values of friction dimensionless number (Nf) and dimensionless number of entrainment (NE), the regime of the turbidity currents is Negligible Friction and Negligible Entrainment in the Dez dam reservoir, and the thickness of the turbid layer is assessed as a function of concentration, settling velocity of particles and entrainment. A positive correlation between measurement and model values has shown that this model is the profitable option for estimating the thickness of turbidity currents in dam reservoirs.

Investigation on trophic state index by artificial neural networks (case study: Dez Dam of Iran)

Dam construction and surface runoff control is one of the most common approaches for water-needs supply of human societies. However, the increasing development of social activities and hence the subsequent increase in environmental pollutants leads to deterioration of water quality in dam reservoirs and eutrophication process could be intensified. So, the water quality of reservoirs is now one of the key factors in operation and water quality management of reservoirs. Hence, maintaining the quality of the stored water and identification and examination of changes along time has been a constant concern of humans that involves the water authorities. Traditionally, empirical trophic state indices of dam reservoirs often defined based on changes in concentration of effective factors (nutrients) and its consequences (increase in chlorophyll a), have been used as an efficient tool in the definition of dam reservoirs quality. In recent years, modeling techniques such as artificial neural networks have enhanced the prediction capability and the accuracy of these studies. In this study, artificial neural networks have been applied to analyze eutrophication process in the Dez Dam reservoir in Iran. In this paper, feed forward neural network with one input layer, one hidden layer and one output layer was applied using MATLAB neural network toolbox for trophic state index (TSI) analysis in the Dez Dam reservoir. The input data of this network are effective parameters in the eutrophication: nitrogen cycle parameters and phosphorous cycle parameters and parameters that will be changed by eutrophication: Chl a, SD, DO and the output data is TSI. Based on the results from estimation of modified Carlson trophic state index, Dez Dam reservoir is considered to be eutrophic in the early July to mid-November and would be mesotrophic with decrease in temperature. Therefore, a decrease in water quality of the dam reservoir during the warm seasons is expectable. The results indicated that artificial neural network (ANN) is a suitable tool for quality modeling of reservoir of dam and increment and decrement of nutrients in trend of eutrophication. Therefore, ANN is a suitable tool for quality modeling of reservoir of dam.

Nonlinear Seismic Assessment of Arch Dams and Investigation of Joint Behavior Using Endurance Time Analysis Method

At the present study, application of endurance time analysis (ETA) method in seismic evaluation of arch dams is investigated. ETA is a time-history based dynamic pushover procedure, which utilizes a set of predesigned intensifying acceleration functions to estimate the responses of the structural systems in various seismic excitation levels. Dez dam was chosen as the case study and all contraction and peripheral joints were modeled based on as-built drawings. The reservoir was modeled as a compressible medium and the foundation was assumed to be massless. Results show that ETA method is able to estimate dynamic responses of the dam with acceptable accuracy in comparison with time history analysis (THA). The great advantage of ETA method lies on the noticeable reduction of the computational demand in comparison with THA for considering seismic behaviors of the infrastructures.