Abstract Flood forecasting has become necessary for dam management during extreme hydrological events. The lack of streamflow data in ungauged watersheds of arid and semi-arid regions makes the assessment of water resources di cult. In this paper, the Hydrologic Modeling System developed by the Hydrologic Engineering Center (HEC-HMS) was applied to the Oued El Hachem watershed. Calibration and validation of the model have been performed, taking into account the lag time and the curve number CN that is expressed as a function of soil group, land use and antecedent runo condition. The model was evaluated on the basis of the coe cient of determination, the Nash Sutcli e E ciency (NSE), and the percentage di erences between peak and volume. Performance indices of calibration showed a good agreements between observed and computed flows. The validation of the model has given satisfactory results. The calibrated model can be used to manage the dam of Boukerdane during extreme rainfall events by forecasting the induced hydrographs from which adequate procedures will be operated in order to ensure the safety of the dam against possible overtopping.
摘要在极端水文条件下，洪水预报已成为大坝管理的必要条件。由于干旱半干旱区未测量的流域缺乏流量数据，使得水资源评价存在困难。本文将水文工程中心开发的水文模拟系统(HEC-HMS)应用于Oued El Hachem流域。考虑到滞后时间和曲线数CN(表示为土壤类型、土地利用和先前运行条件的函数)，对模型进行了校准和验证。该模型的评价依据是确定系数、Nash sutli - e效率(NSE)和峰值与体积之间的百分比差。标定的性能指标表明，实测流量与计算流量吻合较好。模型的验证结果令人满意。校准后的模型可用于在极端降雨事件期间通过预测诱发的水文曲线来管理布克尔丹大坝，由此将运行适当的程序，以确保大坝的安全，防止可能的溢流。
{"title":"Extreme Rainfall-Runo Events Modeling Using HEC-HMS Model for Oued El Hachem Watershed, Northern Algeria","authors":"A. Haddad","doi":"10.2478/heem-2022-0004","DOIUrl":"https://doi.org/10.2478/heem-2022-0004","url":null,"abstract":"Abstract Flood forecasting has become necessary for dam management during extreme hydrological events. The lack of streamflow data in ungauged watersheds of arid and semi-arid regions makes the assessment of water resources di cult. In this paper, the Hydrologic Modeling System developed by the Hydrologic Engineering Center (HEC-HMS) was applied to the Oued El Hachem watershed. Calibration and validation of the model have been performed, taking into account the lag time and the curve number CN that is expressed as a function of soil group, land use and antecedent runo condition. The model was evaluated on the basis of the coe cient of determination, the Nash Sutcli e E ciency (NSE), and the percentage di erences between peak and volume. Performance indices of calibration showed a good agreements between observed and computed flows. The validation of the model has given satisfactory results. The calibrated model can be used to manage the dam of Boukerdane during extreme rainfall events by forecasting the induced hydrographs from which adequate procedures will be operated in order to ensure the safety of the dam against possible overtopping.","PeriodicalId":53658,"journal":{"name":"Archives of Hydroengineering and Environmental Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48266306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Khuram Riaz, H. A. S. Aslam, Muhammad Waseem Yaseen, Hafiz Haseeb Ahmad, Alireza Khoshkonesh, Sadaf Noshin
Abstract Kunhar River hydrology and hydraulic design of a bridge on this river are being studied using HEC-Geo-RAS and Hydrologic Engineering Centers River Analysis System (HEC-RAS). The river flows in the northern part of Pakistan and is 170 km long. On both sides of the river, there are residential settlements. The river hydraulics is studied by using 30-metre remotely sensed shuttle radar topographic mission - digital elevation model (SRTM DEM) and Arc Map. 32 cross-sections are imported from Geographic Information System (GIS) to HEC-RAS. On historical peak flow results, the extreme value frequency distribution is applied, and a flood is determined for a 100-year return period, with a discharge estimated as 2223 cubic metres. Three steady flow profiles are adopted for HEC-RAS, the first is for the maximum historical peak data, the second is for the 100-year return period, and the third profile is for the latter 100-year period with a safety factor of 1.28. With remote sensing-based assessments, the proposed location for a bridge is determined and then verified with a field survey which was physically conducted. The maximum water height estimated in the river is about 4.26 m. This bridge will facilitate about 50 thousand population of Masahan and its surroundings. It will create a shortest link between Khyber Pakhtunkhwa and Azad Kashmir and thus will enhance tourism and trade activities.
{"title":"Flood Frequency Analysis and Hydraulic Design of Bridge at Mashan on River Kunhar","authors":"Khuram Riaz, H. A. S. Aslam, Muhammad Waseem Yaseen, Hafiz Haseeb Ahmad, Alireza Khoshkonesh, Sadaf Noshin","doi":"10.2478/heem-2022-0001","DOIUrl":"https://doi.org/10.2478/heem-2022-0001","url":null,"abstract":"Abstract Kunhar River hydrology and hydraulic design of a bridge on this river are being studied using HEC-Geo-RAS and Hydrologic Engineering Centers River Analysis System (HEC-RAS). The river flows in the northern part of Pakistan and is 170 km long. On both sides of the river, there are residential settlements. The river hydraulics is studied by using 30-metre remotely sensed shuttle radar topographic mission - digital elevation model (SRTM DEM) and Arc Map. 32 cross-sections are imported from Geographic Information System (GIS) to HEC-RAS. On historical peak flow results, the extreme value frequency distribution is applied, and a flood is determined for a 100-year return period, with a discharge estimated as 2223 cubic metres. Three steady flow profiles are adopted for HEC-RAS, the first is for the maximum historical peak data, the second is for the 100-year return period, and the third profile is for the latter 100-year period with a safety factor of 1.28. With remote sensing-based assessments, the proposed location for a bridge is determined and then verified with a field survey which was physically conducted. The maximum water height estimated in the river is about 4.26 m. This bridge will facilitate about 50 thousand population of Masahan and its surroundings. It will create a shortest link between Khyber Pakhtunkhwa and Azad Kashmir and thus will enhance tourism and trade activities.","PeriodicalId":53658,"journal":{"name":"Archives of Hydroengineering and Environmental Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49253963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Kuzmych, Oleh Furmanets, S. Usatyi, O. Kozytskyi, Nazar Mozol, A. Kuzmych, V. Polishchuk, H. Voropai
Abstract The paper focuses on research on improving the water supply of drainage systems of humid areas in the context of anthropogenic climate change. The aim of the research is to elaborate on the ways for increasing the available water supply of drainage systems and restoring active water regulation on reclaimed lands in a changing climate. Reclaimed lands are the main factor of sustainable agricultural production in Ukraine and guarantors of its stability. The area of drained lands in Ukraine is about 3.2 million hectares, including 2.3 million hectares drained with the help of closed drainage; in an area of 1.3 million hectares a two-way regulation of the soil water regime is carried out. An increase in air temperature and uneven distribution of precipitation, which has a torrential, local character in the warm period, do not allow for the e ective accumulation of moisture. The recurrence of droughts in di erent justified climatic zones of Ukraine has increased by 20–40%, which prevents sustainable agricultural production in the zone of su cient atmospheric moisture, in particular the Polesie Ecoregion. In this paper, the analysis of water consumption of reclaimed lands in the Polesie Ecoregion of Ukraine is carried out, on the examples of the drainage system “Maryanivka” and the calculation of the water supply for the corn and winter wheat.
{"title":"Water Supply of the Ukrainian Polesie Ecoregion Drained Areas in Modern Anthropogenic Climate Changes","authors":"L. Kuzmych, Oleh Furmanets, S. Usatyi, O. Kozytskyi, Nazar Mozol, A. Kuzmych, V. Polishchuk, H. Voropai","doi":"10.2478/heem-2022-0006","DOIUrl":"https://doi.org/10.2478/heem-2022-0006","url":null,"abstract":"Abstract The paper focuses on research on improving the water supply of drainage systems of humid areas in the context of anthropogenic climate change. The aim of the research is to elaborate on the ways for increasing the available water supply of drainage systems and restoring active water regulation on reclaimed lands in a changing climate. Reclaimed lands are the main factor of sustainable agricultural production in Ukraine and guarantors of its stability. The area of drained lands in Ukraine is about 3.2 million hectares, including 2.3 million hectares drained with the help of closed drainage; in an area of 1.3 million hectares a two-way regulation of the soil water regime is carried out. An increase in air temperature and uneven distribution of precipitation, which has a torrential, local character in the warm period, do not allow for the e ective accumulation of moisture. The recurrence of droughts in di erent justified climatic zones of Ukraine has increased by 20–40%, which prevents sustainable agricultural production in the zone of su cient atmospheric moisture, in particular the Polesie Ecoregion. In this paper, the analysis of water consumption of reclaimed lands in the Polesie Ecoregion of Ukraine is carried out, on the examples of the drainage system “Maryanivka” and the calculation of the water supply for the corn and winter wheat.","PeriodicalId":53658,"journal":{"name":"Archives of Hydroengineering and Environmental Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46839892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Local scour around bridge piers impairs the stability of bridges’ structures. Therefore, a delicate estimation of the local scour depth is vital in designing the bridge piers foundations. In this research, MATLAB software was used to train artificial neural network (ANN) models with four hundred laboratory datasets from different laboratory studies, including five parameters: pier diameter, flow depth flow velocity, critical sediment velocity, sediment particle size, and equilibrium local scour depth. The outcomes present that the ANN model with the Levenberg-Marquardt algorithm and 11 nodes in the single hidden layer gives an accurate estimation better than other ANN models trained with different training algorithms based on the regression results and mean squared error values. Besides, the ANN model accurately provides predicted local scour depth and is better than linear and nonlinear regression models. Furthermore, sensitivity analysis shows that removing pier diameter from training parameters diminishes the reliability of prediction.
{"title":"Artificial Neural Network for Estimation of Local Scour Depth Around Bridge Piers","authors":"A. A. Ali, M. Günal","doi":"10.2478/heem-2021-0005","DOIUrl":"https://doi.org/10.2478/heem-2021-0005","url":null,"abstract":"Abstract Local scour around bridge piers impairs the stability of bridges’ structures. Therefore, a delicate estimation of the local scour depth is vital in designing the bridge piers foundations. In this research, MATLAB software was used to train artificial neural network (ANN) models with four hundred laboratory datasets from different laboratory studies, including five parameters: pier diameter, flow depth flow velocity, critical sediment velocity, sediment particle size, and equilibrium local scour depth. The outcomes present that the ANN model with the Levenberg-Marquardt algorithm and 11 nodes in the single hidden layer gives an accurate estimation better than other ANN models trained with different training algorithms based on the regression results and mean squared error values. Besides, the ANN model accurately provides predicted local scour depth and is better than linear and nonlinear regression models. Furthermore, sensitivity analysis shows that removing pier diameter from training parameters diminishes the reliability of prediction.","PeriodicalId":53658,"journal":{"name":"Archives of Hydroengineering and Environmental Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47866828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Chau, Nguyen The Toan, Do Anh Duc, Nguyễn Hà Linh
Abstract Bankfull discharge is an important criterion for flash flood warnings. In this study, the authors propose a new approach to determine the bankfull discharge for basins in Ha Giang province, Vietnam. The study combines the field survey to determine the bankfull discharge through the bankfull indicators and develop a multivariate regression equation between the bankfull discharge and the basin characteristics. The results of the study give a simple equation with 2 independent variables. They are the catchment area and the main river length. They show a strong relationship with the bankfull discharge with the R2 indexes in developing and validating process equal to 95.3% and 92.7%, respectively. With this approach, the workload is significantly reduced. However, the accuracy and flexibility of the total discharge calculation are enhanced. This will be the foundation to reduce uncertainty in flash flood warnings.
{"title":"Developing the Regression Equations to Determine the Bankfull Discharge from the Basin Characteristics","authors":"T. Chau, Nguyen The Toan, Do Anh Duc, Nguyễn Hà Linh","doi":"10.2478/heem-2021-0006","DOIUrl":"https://doi.org/10.2478/heem-2021-0006","url":null,"abstract":"Abstract Bankfull discharge is an important criterion for flash flood warnings. In this study, the authors propose a new approach to determine the bankfull discharge for basins in Ha Giang province, Vietnam. The study combines the field survey to determine the bankfull discharge through the bankfull indicators and develop a multivariate regression equation between the bankfull discharge and the basin characteristics. The results of the study give a simple equation with 2 independent variables. They are the catchment area and the main river length. They show a strong relationship with the bankfull discharge with the R2 indexes in developing and validating process equal to 95.3% and 92.7%, respectively. With this approach, the workload is significantly reduced. However, the accuracy and flexibility of the total discharge calculation are enhanced. This will be the foundation to reduce uncertainty in flash flood warnings.","PeriodicalId":53658,"journal":{"name":"Archives of Hydroengineering and Environmental Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49633448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In many countries of the northern hemisphere during winter period ice forms appear on various water bodies, which results in significant changes of physical, chemical and ecological conditions. These changes are different in rivers, channels, lakes or once-through reservoirs. On the terrain of Poland ice always caused considerable problems affecting intensive inland navigation and other river use. These problems appeared especially on the Vistula River, which in 17th and 18th century was one of the most navigable rivers in Europe. The Vistula is the largest Polish river, which flows from the south in the Carpathian Mountains to the Baltic Sea in the north. It is the second largest river, after Neva, of the Baltic Sea catchment. The length of the Vistula is 1047 km and its catchment amounts to 194 thousand km2. The predominant part of the Vistula river basin (87%) is now on Polish territory and the remaining (13%) catchment is in Belarus, Ukraine and Slovakia. The course of the Vistula can be divided into three distinctly different sections: upper, middle and lower. These river sections have appropriate catchments with their tributaries. There are hydraulic structures on the main river course and on its tributaries which serve navigation, hydroenergy, flood protection, water supply and recreation. All over the Vistula catchment there are frequent floods during spring and summer time resulting from excessive precipitation but in winter caused by ice phenomena. Numerous flow problems appear especially along the lower Vistula course because of ice phenomena and they result very often in severe flood problems. The Vistula has a very variable time and spatial discharge, because of existing climate conditions over its catchment. The aim of the paper is to present hydraulic and hydrologic characteristics of the Lower Vistula river with special emphasis on the management of this river section for navigation, hydroenergy, flood protection and water supply in view of ice phenomena appearing there. Information concerning changes of water characteristics due to various water temperatures are presented as well as on the formation of various forms of ice in flowing water. Numerous ice studies were carried out in Poland and especially on the Lower Vistula section as it was very ice prone and where many ice jams and ice-jam floods occurred. A special hydraulic situation existed at the mouth of the Vistula, which caused important floods in the 18th century and resulted in the construction of a special direct channel to the sea (Przekop Wisły) solving flood problems in this area. Information is presented on changes in open channel flow due to the appearance of ice cover and other ice forms. The paper includes ample information on the run, consequences and studies connected with a very important ice-jam-flood on the upper part of Włocławek reservoir in 1982.
{"title":"The Lower Vistula and Its Ice Problems","authors":"W. Majewski","doi":"10.1515/heem-2021-0004","DOIUrl":"https://doi.org/10.1515/heem-2021-0004","url":null,"abstract":"Abstract In many countries of the northern hemisphere during winter period ice forms appear on various water bodies, which results in significant changes of physical, chemical and ecological conditions. These changes are different in rivers, channels, lakes or once-through reservoirs. On the terrain of Poland ice always caused considerable problems affecting intensive inland navigation and other river use. These problems appeared especially on the Vistula River, which in 17th and 18th century was one of the most navigable rivers in Europe. The Vistula is the largest Polish river, which flows from the south in the Carpathian Mountains to the Baltic Sea in the north. It is the second largest river, after Neva, of the Baltic Sea catchment. The length of the Vistula is 1047 km and its catchment amounts to 194 thousand km2. The predominant part of the Vistula river basin (87%) is now on Polish territory and the remaining (13%) catchment is in Belarus, Ukraine and Slovakia. The course of the Vistula can be divided into three distinctly different sections: upper, middle and lower. These river sections have appropriate catchments with their tributaries. There are hydraulic structures on the main river course and on its tributaries which serve navigation, hydroenergy, flood protection, water supply and recreation. All over the Vistula catchment there are frequent floods during spring and summer time resulting from excessive precipitation but in winter caused by ice phenomena. Numerous flow problems appear especially along the lower Vistula course because of ice phenomena and they result very often in severe flood problems. The Vistula has a very variable time and spatial discharge, because of existing climate conditions over its catchment. The aim of the paper is to present hydraulic and hydrologic characteristics of the Lower Vistula river with special emphasis on the management of this river section for navigation, hydroenergy, flood protection and water supply in view of ice phenomena appearing there. Information concerning changes of water characteristics due to various water temperatures are presented as well as on the formation of various forms of ice in flowing water. Numerous ice studies were carried out in Poland and especially on the Lower Vistula section as it was very ice prone and where many ice jams and ice-jam floods occurred. A special hydraulic situation existed at the mouth of the Vistula, which caused important floods in the 18th century and resulted in the construction of a special direct channel to the sea (Przekop Wisły) solving flood problems in this area. Information is presented on changes in open channel flow due to the appearance of ice cover and other ice forms. The paper includes ample information on the run, consequences and studies connected with a very important ice-jam-flood on the upper part of Włocławek reservoir in 1982.","PeriodicalId":53658,"journal":{"name":"Archives of Hydroengineering and Environmental Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45728174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Kuzmych, G. Voropay, Nelya Moleshcha, O. Babitska
Abstract The paper focuses on research on improving the water supply of drainage systems of humid areas in the context of climate change. The aim of the research is to elaborate on the ways for increasing the available water supply of drainage systems and restoring active water regulation on reclaimed lands in a changing climate. The paper presents the results of the research on improving the available water supply of drainage systems in the humid zone of Ukraine in a changing climate. It was specified in the face of increasing water scarcity providing the optimal water regime regulation on drained lands is possible due to the increase in the available water supply of drainage systems. It can be achieved thanks to the accumulating capacity of reclaimed areas, namely usage of free soil capacity of the aeration zone and open canals, accumulation of water reserve volumes in storage tanks due to the accumulation of surface and drainage runoff. Taking into account the design features of different types of drainage systems, existing water management technologies, characteristics of water sources and their close proximity to the drainage systems, the technological schemes of water intake from rivers and reservoirs, and its supply to the drained areas for irrigation needs were developed. In a face of increasing water scarcity, it is also expedient to apply resource-saving technologies to control the available water supply for crops.
{"title":"Improving Water Supply Capacity of Drainage Systems at Humid Areas in the Changing Climate","authors":"L. Kuzmych, G. Voropay, Nelya Moleshcha, O. Babitska","doi":"10.1515/heem-2021-0003","DOIUrl":"https://doi.org/10.1515/heem-2021-0003","url":null,"abstract":"Abstract The paper focuses on research on improving the water supply of drainage systems of humid areas in the context of climate change. The aim of the research is to elaborate on the ways for increasing the available water supply of drainage systems and restoring active water regulation on reclaimed lands in a changing climate. The paper presents the results of the research on improving the available water supply of drainage systems in the humid zone of Ukraine in a changing climate. It was specified in the face of increasing water scarcity providing the optimal water regime regulation on drained lands is possible due to the increase in the available water supply of drainage systems. It can be achieved thanks to the accumulating capacity of reclaimed areas, namely usage of free soil capacity of the aeration zone and open canals, accumulation of water reserve volumes in storage tanks due to the accumulation of surface and drainage runoff. Taking into account the design features of different types of drainage systems, existing water management technologies, characteristics of water sources and their close proximity to the drainage systems, the technological schemes of water intake from rivers and reservoirs, and its supply to the drained areas for irrigation needs were developed. In a face of increasing water scarcity, it is also expedient to apply resource-saving technologies to control the available water supply for crops.","PeriodicalId":53658,"journal":{"name":"Archives of Hydroengineering and Environmental Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46865559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In this paper, flow through a free triangular orifice is considered. The comparison of two formulas was conducted for discharge calculations: a large orifice formula and a small orifice formula. The results show that, above a certain value of upstream head to orifice height ratio there is no need for small-large formula discrimination. The differences in the outcomes for the two formulas are negligible for upstream head to orifice height ratios greater than 3. This means that a small orifice formula can be used instead of a large orifice formula. Calculations were performed for different variants of triangle orientation (with tip downwards, sidewards and upwards) as well as for different dimensions of orifice (equilateral and isosceles). The calculations also included different submergence levels of the upper edge of the orifice and variable dimensions of the orifice with constant upstream head. Neither of these conditions affect the relative deviation values for small and large orifice formulas.
{"title":"Discharge of a Triangular Orifice under Free Flow Conditions","authors":"A. Sosnowska","doi":"10.1515/heem-2021-0002","DOIUrl":"https://doi.org/10.1515/heem-2021-0002","url":null,"abstract":"Abstract In this paper, flow through a free triangular orifice is considered. The comparison of two formulas was conducted for discharge calculations: a large orifice formula and a small orifice formula. The results show that, above a certain value of upstream head to orifice height ratio there is no need for small-large formula discrimination. The differences in the outcomes for the two formulas are negligible for upstream head to orifice height ratios greater than 3. This means that a small orifice formula can be used instead of a large orifice formula. Calculations were performed for different variants of triangle orientation (with tip downwards, sidewards and upwards) as well as for different dimensions of orifice (equilateral and isosceles). The calculations also included different submergence levels of the upper edge of the orifice and variable dimensions of the orifice with constant upstream head. Neither of these conditions affect the relative deviation values for small and large orifice formulas.","PeriodicalId":53658,"journal":{"name":"Archives of Hydroengineering and Environmental Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48933067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mina Parvizishad, S. Naseri, R. Nabizadeh, Abdollah Sohrabi Bidar, A. Mahvi, F. Goodarzi
Abstract Dam construction is one of the most popular solutions for managing water resources. In recent years, changes in patterns of regional seismicity associated with large impoundment dams have raised concerns among environmentalists. In this study, five large dams located in Iran were studied from this perspective. The Gutenberg-Richter, linear regression and T-test were used to examine the seismic changes in the radius of 100 km of each of the dams during a twenty-five-year period before and after the construction of the dams. The results revealed that the seismicity level and relative density of large and small earthquakes in three of these dams have increased after dam construction. A significant difference between the magnitude of earthquakes, as well as the number of earthquakes before and after the construction of dams in the region, was recognized. However, the results of the T-test statistical analysis indicated that the mean depth of the earthquakes and their distance from the dams before and after construction have not changed significantly. Overall, these results indicated that the construction of large impoundment dams has been associated with some changes in patterns of regional seismicity. The findings would guide researchers to further investigate the type of impacts that dam construction may have on seismicity patterns.
{"title":"Analyzing the Impact of Large Dams on Seismicity Patterns around Their Locations","authors":"Mina Parvizishad, S. Naseri, R. Nabizadeh, Abdollah Sohrabi Bidar, A. Mahvi, F. Goodarzi","doi":"10.1515/heem-2021-0001","DOIUrl":"https://doi.org/10.1515/heem-2021-0001","url":null,"abstract":"Abstract Dam construction is one of the most popular solutions for managing water resources. In recent years, changes in patterns of regional seismicity associated with large impoundment dams have raised concerns among environmentalists. In this study, five large dams located in Iran were studied from this perspective. The Gutenberg-Richter, linear regression and T-test were used to examine the seismic changes in the radius of 100 km of each of the dams during a twenty-five-year period before and after the construction of the dams. The results revealed that the seismicity level and relative density of large and small earthquakes in three of these dams have increased after dam construction. A significant difference between the magnitude of earthquakes, as well as the number of earthquakes before and after the construction of dams in the region, was recognized. However, the results of the T-test statistical analysis indicated that the mean depth of the earthquakes and their distance from the dams before and after construction have not changed significantly. Overall, these results indicated that the construction of large impoundment dams has been associated with some changes in patterns of regional seismicity. The findings would guide researchers to further investigate the type of impacts that dam construction may have on seismicity patterns.","PeriodicalId":53658,"journal":{"name":"Archives of Hydroengineering and Environmental Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43046909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The quadric-surfaced sludge digester (QSD), also known as the egg-shaped sludge digester, has proven its advantages over traditional cylindrical digesters recently. A reduction in operational cost is the dominant factor. Its shell can be described as a revolution of a parabola with the apex and base being either tapered or spherical. This shape provides a surface free of discontinuities, which is advantageous regarding the efficiency during mixing. Since the shape does not produce areas of inactive fluid motion within the tank, sludge settlement and an eventual grit build-up are avoided. The stresses developed in the shell of the sludge digester, vary along the meridian and equatorial diameters. A non-dimensional parameter, ξ, defines the height-to-diameter aspect ratio which is used to delineate the parametric boundary conditions of the shell’s surface. Three groups of analyses were conducted to determine the orthogonal stresses in the shell of the QSD. The first-principles numerical models ran reasonably quickly, and many simulations were made during the study. The results showed that they were in within the range 5.34% to 7.2% to 2D FEA results. The 3D FEA simulation results were within the range of 8.3% to 9.2% to those from the MATLAB time-history models. This is a good indicator that the first principles numerical models are an excellent time-saving method to predict the behaviour of the QSD under seismic excitation. Upon examining the criteria for the design, analysing the results for the 2D FEA simulations showed that the fill height is not a significant variable with sloshing however the 3D FEA showed that the hydrostatic pressure is a significant variable. With the maximum tensile stress of the 3D-printed Acrylonitrile Butadiene Styrene (ABS)-a common thermoplastic polymer typically used for injection molding applications, being 24.4 MPa, the overall maximum stress of 5.45 MPa, the material can be a viable option for the use of QSD construction in small island developing states (SIDS).
{"title":"Modelling of Quadratic-Surface Sludge Digesters by Smoothed Particle Hydrodynamics (SPH) – Finite Element (FE) Methods","authors":"K. Tota-Maharaj, G. Nounu, Navin. Ramroop","doi":"10.1515/heem-2020-0003","DOIUrl":"https://doi.org/10.1515/heem-2020-0003","url":null,"abstract":"Abstract The quadric-surfaced sludge digester (QSD), also known as the egg-shaped sludge digester, has proven its advantages over traditional cylindrical digesters recently. A reduction in operational cost is the dominant factor. Its shell can be described as a revolution of a parabola with the apex and base being either tapered or spherical. This shape provides a surface free of discontinuities, which is advantageous regarding the efficiency during mixing. Since the shape does not produce areas of inactive fluid motion within the tank, sludge settlement and an eventual grit build-up are avoided. The stresses developed in the shell of the sludge digester, vary along the meridian and equatorial diameters. A non-dimensional parameter, ξ, defines the height-to-diameter aspect ratio which is used to delineate the parametric boundary conditions of the shell’s surface. Three groups of analyses were conducted to determine the orthogonal stresses in the shell of the QSD. The first-principles numerical models ran reasonably quickly, and many simulations were made during the study. The results showed that they were in within the range 5.34% to 7.2% to 2D FEA results. The 3D FEA simulation results were within the range of 8.3% to 9.2% to those from the MATLAB time-history models. This is a good indicator that the first principles numerical models are an excellent time-saving method to predict the behaviour of the QSD under seismic excitation. Upon examining the criteria for the design, analysing the results for the 2D FEA simulations showed that the fill height is not a significant variable with sloshing however the 3D FEA showed that the hydrostatic pressure is a significant variable. With the maximum tensile stress of the 3D-printed Acrylonitrile Butadiene Styrene (ABS)-a common thermoplastic polymer typically used for injection molding applications, being 24.4 MPa, the overall maximum stress of 5.45 MPa, the material can be a viable option for the use of QSD construction in small island developing states (SIDS).","PeriodicalId":53658,"journal":{"name":"Archives of Hydroengineering and Environmental Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49562876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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