جستجوی مقالات مرتبط با کلیدواژه "sedimentation" در نشریات گروه "مهندسی آب"

Without hydrological models the investigation and management of watersheds can be time-consuming and costly. This study aims to explore various hydrological factors including runoff, sedimentation, evaporation, and transpiration in Pasikhan watershed located in Guilan province. The study also examines the impact of these factors on the Anzali Wetland. To achieve this, the research utilizes the SWAT model. Data on flow discharge, precipitation, and sedimentation for three hydrometric station in the Pasikhan watershed from 1999 to 2020 were obtained from the regional water company of Guilan province. The necessary maps for model execution were obtained using established methods. Predictions for various factors, such as flow rate, sedimentation, surface runoff, evaporation and transpiration, deep aquifer recharge, curve number, deep infiltration, and watershed runoff, were made for the years 2040 and 2071. Discharge-sediment from 1999 to 2011 is used for calibration and for validation used the data from 2012 to 2022 is used. The study also assessed changes in hydrological components caused by climate change using the RCP8.5 scenario and land use changes. The findings demonstrate variations in multiple hydrological elements and precipitation patterns within the catchment basin. The Nash Sutcliffe criterion yielded values between 0.60 and 0.80 for both the calibration and validation phases of the model in terms of flow rate and sedimentation. This indicated that the implementation of the SWAT model is satisfactorily accurate. Results showed that the maximum surface runoff within the basin will reach 485 mm in 2055, coinciding with a rainfall of 1431 mm. Additionally, the study identified the highest levels of evaporation and transpiration as 1707 mm within the RCP8.5 scenarios in 1996. Overall, the research emphasizes the negative impact of sediment generated within the Pasikhan watershed on the Anzali Wetland, highlighting the need for effective control measures to mitigate wetland degradation

Erosion occurs naturally in riverbeds. The high cost and limitations of physical models have led to using mathematical and numerical models. In this research, the two-dimensional mathematical model CCHE2D was applied for the simulation of sediment transport in Saqqez River flows throughout the Kurdistan province to determine the rate of erosion and sedimentation. The Study area includes the main and sub-branches that intersect at the site of Tamogheh village. After analyzing the sensitivity of the model, the model proposed by Wu et al. with a Root Mean Square Error of 0.002 and Mean Absolute Error Percentage of 7.14 was used as the most appropriate relationship for calculating sediments. Finally, it was found that on average, in the study period, sediment deposition was about 82485 cubic meters, erosion was about 18708 cubic meters, and average bed level changes were 0.20 meters. The Khan tributary accounted for 63% of the total erosion of the study period.

The raw water entering the water treatment plants in Guilan province is of surface water type and due to the fact that the soil of the supplying rivers catchment area is highly erodible, in heavy rains the soils washed by runoff enter the rivers or canals and increase the turbidity of raw inflows to the plants above the allowable limits provided in the design. At this time, due to the non-responsiveness of the treatment plant to such high turbidity, the operation of the treatment plant will inevitably be shut down and cause drinking water interruption in the distribution network. In order to settle the suspended solids and reduce the turbidity of water entering the next stage of treatment (filtration), sedimentation ponds are used. Baffle plates create a slow flow and are used to reduce the sedimentation distance of the particle in the sedimentation and clarification process. In this research, the use of baffle plates or flow relief walls in sedimentation ponds in a treatment plant were analyzed using simulation with Camsul software. Results were compared to normal conditions (no baffles or walls) and the feasibility of increasing the efficiency of these ponds and finally the efficiency of existing treatment plants in real volume were investigated.

Given the increasing consumption of potable water in the world, efforts to adopt new solutions for the obtainment of the right amount of desirable water is essential. One of the chief issues facing the majority of industries including water industry is corrosion and sedimentation. The present study was conducted to address the corrosion and sedimentation of drinking water supply and distribution reservoirs in the city of Sough, Kohgiloye-Boyer-Ahmad province. Through descriptive analysis, the Langelier, Raisner, Pokorius, and aggressive indices to determine the corrosion and sedimentation potential of the water supply network were used. This study was aimed measure chemical and physicochemical information of 84 water samples from wells, water reservoirs and allocated water supply network of the area. The samples were collected and analyzed from 2007 to 2016 by the provincial Water and Wastewater Company. The results indicated that the mean indices were -0.589±0.63 (low to moderate corrosion), 8.470±0.797, (low to moderate corrosion), 7.472±0.228 (low to moderate corrosion), respectively and 12.015±0.227 (mild aggressive or very corrosive) respectively. The water supply sources under investigation had low to moderate corrosion and little tendency to develop eggshell sedimentation. The water supply sources of the study area had low to moderate corrosion and had a slight tendency for eggshell sedimentation. Drinking water allocated to Sough water supply network in the direction of joint drinking water transmission of Dehdasht and Sough within 17 km of joint water supply from Sepah Tapeh reservoir (Dehdasht and Sough joint) is separated and directed, within 15 km by the transfer line and pump station, to Sough city. The average values of corrosion and sedimentation indices of the city of Sough water supply and distribution network (Lanzeley, Reisner, Pokoris and aggressive) were 0.63, 6.8, 7.28 and 12.8, respectively which indicate tendency toward sedimentation, relative tendency toward CaCO3, and non-aggressiveness. Despite the fact that the average pH of the joint water resources of both cities was 7.78. In summer, the water pH of Sough allocated water network increased to 8.5. Values and mean values of corrosion and sedimentation indices of Sough water supply network during hot seasons of the year show that the water of this network tends to precipitate. The findings also suggest that the average water temperature of the allocated water supply network in these 15 kilometers of transition which includes the transmission line and surfaced metal reservoirs had an increase in temperature around 10 °C. This temperature rise was due to the environment temperature (above 48 °C), the hot water in metal reservoirs and the surfaced steel transmission line in water supply network components. This physical change of water temperature is the main factor behind sedimentation.

the sediment accumulation in the reservoirs places upstream and downstream of the dam under the influence of ecosystem changes. In order to increase the volume of regulated water in the river basin and prevent the introduction of river sediments into the dam reservoir and as a result of increasing the useful life of the dam and the optimal management of water resources in the given time, the required data from the relevant companies from the Tangab Dam was obtained and Using Karun's analysis software, based on the calculations performed by the software, the modified volume (after sedimentation) after one year and after 50 years from the beginning of operation, using the method of increasing the level to The order of 1021.646 million cubic meters and 605.664 million cubic meters, and also for the method of reducing the level of these numbers is equal to 1021.6 million million Rmkb and 064/580million cubic meters is estimated. Given the reservoir type and sediment volume, the curves of hp and h'p are plotted. According to the power plant's level, the reservoir level of the dam increases with the calculation of sediment distribution by increasing the level after 110 years from the plant's level of utilization, and this also occurs in the method of reducing the level after 100 years.

Sediments transported by water flow, an important factor in the formation of the geometrical structure and morphology of rivers considered. In this paper, the process of sedimentation Karun river was simulated using the Gstars3 software in the range of Ahvaz hydrometric stations to Farsiat a length of about 50 km. The purpose of this study was to select a suitable mathematical model for estimating the sediment transport rate in a way that is able to simulate accurately in the river. Calibration of sedimentary depositional model shows that for the the range the relationship Ackers- White (1973) and (1990) fitted to existing conditions are Karun River. Also sedimentation volume of hydrometric stations in Ahvaz and Farsiat 18.25 and 16.65 million cubic meters per year respectively was estimated. This indicates that the area is strongly depositing.

Water quality management in groundwater aquifers requires accurate water quality monitoring to ensure they meet a variety of relevant standards. Given the rather few reported studies in the field, the present study was designed and implemented to investigate the groundwater quality of Shahr-e-Babak aquifer that is exploited for agricultural, mining, drinking, and industrial consumptions. The kriging and IDW (power:1-3) techniques with spherical, exponential, and Gaussian variogramsare were compared using R2, RMSE, MAE, and RSS indices to find the optimum model for determining the spatial variability of sixteen groundwater quality parameters. Multi-purpose zoning of groundwater quality was accomplished in the ArcGIS environment in terms of the Wilcox, Schuler, drip and sprinkle irrigation as delineated by Iran Power Ministry, corrosiveness, and sedimentation standards as well as the WHO and IRISI indices before spatial correlations were determined accordingly. Based on the water quality zoning maps thus derived, Langelier, Corrosiveness, and Ryznar indices were several times larger than the threshold levels across the whole aquifer plain, indicating the wide corrosiveness of the water in industrial applications. The results also revelaed that 93% of the groundwater in the plain area was classified as C4-S1 and C4-S2, which are unsuitable for irrigation, while only 1.3% of the groundwater was acceptable for drinking uses. Drip irrigation zoning revealed that 64% of the plain area had the lowest water quality.The undesirable quality zones in a vast area of the aquifer investigated calls for accurate quality monitoring and management to meet the development objectives in the region.

Debris flows are including of mass movement that usually happen in watersheds and play an important role in sedimentation in mountainous regions. In many cases، this phenomenon be confused with flooding. In this research، the debris flow was investigated that happened in Tool Baneh''s watershed southern Gorgan، Golestan province in summer 2010، after a heavy rainfall. In this regard، 40 samples that consist of depositions، recorded data، and lateral landslides were investigated and analyzed according to sedimentology indicators. Then، Krumbine and symmetry sedimentological indices and trask coefficient were also computed for each sample. The mean of Krumbine in the sediment samples and the mean of sorting index is 0. 81 and -0. 73، respectively. The negative symmetry index reflects more sorting on the fine particle of grading curve. All indices showed very poorly sorting of deposition of happened flow and its difference with flooding. Also average and lowest coefficient values of deposits trask were 6. 83 and 3. 57، respectively. Results of comparing sedimentological coefficients in origin and sedimentation from debris flow showed that there is no significant statistically differences between sedimentological indices in above two regions.

Characteristics of basins and their erosion and sedimentation are of great importance in the studies of water resources. Moreover, soil erosion is a problem that causes great damage to the economy of the country every year and reduces or kills soil fertility. Lack of information on soil erosion studies is the most important problem in these basins. Therefor this study aimed to delineate Manshad basin erosion features as well as to save time and cost and to increase the accuracy of the test. In this study, six indicators of surface geology, namely soil type, precipitation, slope, land use and vegetation type were investigated to assess soil erosion by using remote sensing and GIS methods. The results showed that the Quaternary deposits play a significant role in reducing erosion in the area. Formation of Cretaceous limestone increases erosion in sub basin 4 (22.74 %). Moreover, the most area (13.65 Km2) has the highest average erosion rate of about 640.93 M3/Km2. Therefore it is suggested that, to reduce erosion, the dramatic increase of livestock in the region should be banned. Watershed protection and improvement of the plantation should be taken into consideration to prevent further erosion in this region.

Songun copper processing plant’s feed is 61% grade porphyry which changes to 30% grade copper concentrate after flotation. 2100 m3/h water is required for concentrating process in this plant. During the concentrating process, 1204 m3/h tailing with a solidity of 50% are produced and transferred to the tailing dam. The high volume of the waste water, which contains chemical additives and discharges to the environment, may lead to numerous environmental issues. In this study, through the investigating the factors which affect deposition, the optimum deposition conditions of the tailing slurry was determined using Taguchi experiment design method. Then, by designing and making a pilot scale deep cone thickener along with applying the optimum deposition conditions in continuous feeding, an underflow with a solidity of 61% was gained. Thus, the average percentage of Songun coppers’ tailing thickener underflow solidity is 48% which will be improved by the proposed method that leads to 170 m3/h increase in the amount of reclaimed water from tail thickener and also a decrease in raw water and chemical drugs consumption in the concentrating process and thus, a reduce in the number of environmental impacts of effluents discharging to the dam.

Sedimentation in reservoirs is one of the most serious problems of most dams. Sustainable reservoir management necessitates the deposited sediment most be removed to reduce the inactive storage of the reservoir. Different methods can be used accordingly to control sedimentation and maintenance of the dam reservoir. Dredging, sluicing, and flushing are among these methods. In flushing methods, the previously deposited sediment would be flushed from the reservoir by opening the bottom outlets. In the pressure flushing method, the amount of the flushed sediments depends on many parameters such as the water depth over the bottom outlets, the discharge through bottom outlets, the size of the outlets, the geometry of the reservoir, and the size and type of the sediments. In this study laboratory experiments were performed to investigate the flushing processes during pressure flushing. The effects of the discharge through bottom outlets and the water depth over the bottom outlets were investigated using 3 sizing of non-cohesive sediments (fine, medium, and coarse sediments). The physical model was constructed in the Hydraulic Laboratory at the Water and Science Collage of the University of Shahid Chamran, Ahwaz, Iran. The results indicated that the amount of sediment flushed increases as the depth of water in reservoir decreases and the discharge from outlets increases. Under the same conditions the flushed sediment volume is increased moving from coarse sediments to fine sediments.