rss_2.0Sciendo RSS Feed for Archives of Hydro-Engineering and Environmental Mechanicshttps://sciendo.com/journal/HEEMhttps://www.sciendo.comhttps://sciendo-parsed.s3.eu-central-1.amazonaws.com/6471e584215d2f6c89db448f/cover-image.jpghttps://sciendo.com/journal/HEEM140216https://sciendo.com/article/10.2478/heem-2024-0006<abstract> <title style='display:none'>Abstract</title> <p>The determination of resistance coefficients, such as Chezy’s or Manning’s coefficients, requires a great deal of sensible thought in order to express these coefficients better and more extensively in free-surface channels and aqueducts. This can be achieved if the expression of the resistance coefficient is well stated and takes into account the maximum number of parameters for governing flows in channels. However, in most practical cases, if these coefficients are not expressed by implicit models, they are generally taken as constant and arbitrary. To this end and in a rational manner, the dimensioning and design of channels requires the expression of the resistance coefficient in an easily and explicit form by adopting numerous flow parameters, namely the roughness of the walls, the aspect ratio, the slope of the channels and essentially the viscosity of the liquid. To achieve this aim, the Chezy’s resistance coefficient <italic>C</italic> is identified using the rough model method (RMM), which gives the discharge under uniform flow conditions appropriate to a round-cornered rectangle channel.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2024-00062024-08-01T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2024-0004<abstract> <title style='display:none'>Abstract</title> <p>This study presents the use, and its advantages, of artificial intelligence methods to predict the discharge coefficient (<italic>C_w</italic>), considering the approach conditions of the labyrinth weir type D. The study suggests modifying the training and validation rates in AI tools, which are often fixed without proper justification in previous studies. Unlike most studies that use geometric dimensions as inputs, this work focuses on the approach conditions (the emplacement of the labyrinth weir and filling the alveoli upstream and downstream) of the labyrinth weir type D. The results, based on laboratory experiments, show that these modified inputs significantly impact the e ciency and cost of constructing the weir. Moreover, the <italic>C</italic>_w predictions based on these inputs are highly satisfactory compared to laboratory test results. In terms of training and validation ratios, the study confirms that the optimal ratio is 70/30 for accurate and highly satisfactory predictions.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2024-00042024-07-05T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2024-0005<abstract> <title style='display:none'>Abstract</title> <p>Desirable conditions of airflow should be provided for spillway chute aerators in two-phase air-water flow, especially in large-width chutes. There is no general approach to determine air entrainment, concentration distribution, and submergence along a chute introduced by an aerator shaft. The two-phase air-water modeling of Gavoshan dam in Iran as a case study of chute flow, its aerator, and the characteristics of flow into the cavity formed below the jet have been numerically investigated, and the results obtained have been validated against the laboratory experiments. The hydraulic parameters of the cavity and aerator shaft were determined to evaluate their performance and emphasize the importance of a proper aerator design. Sections with a greater distance from the bottom of the chute exhibit higher pressure magnitudes, while the mean air concentration values in the cavity are smaller in sections close to a ramp. Higher water discharge, lower pressure head in sections near the bottom of the cavity, and lower air concentration in sections near the ramp into the cavity increase the probability of cavitation occurrence.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2024-00052024-07-05T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2024-0003<abstract> <title style='display:none'>Abstract</title> <p>The paper is devoted to the long-term project concerning monitoring and stability analysis of a 40 m high phosphogypsum heap located at Wiślinka, Poland. The research presented in the paper focused on collecting and processing rainfall data, which subsequently allows us to perform numerical simulation of rainfall impact on heap’s behaviour. Such analysis requires time history of rainfall intensity, that is recorded by an automatic precipitation station. Since this is not common monitoring equipment, the characteristics of the station installed in the immediate vicinity of the heap are presented, and the data obtained in two experiments conducted in the laboratory are discussed. The analysis revealed that di erences between introduced and measured total rain are as large as 10% for very heavy rains. Moreover, the recorded maximum rainfall intensity often includes errors. The data processing procedure to obtain time history of rainfall intensity is presented on the basis of data collected in the first half of the hydrological year 2023 (the first period of the station’s operation). The total precipitation registered was 107 mm, and the maximum daily rain was only 26 mm. However, first single and multi-stage rainfall models for the Wiślinka region that would be applied into numerical simulations are presented.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2024-00032024-05-31T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2024-0002<abstract> <title style='display:none'>Abstract</title> <p>A system optimization method was used, which consists in the consistent justification of optimal technological and constructive solutions and parameters of drainage polder systems during the development of their projects. This is done in compliance with modern economic and environmental requirements according to criteria and models for di erent levels of management decision-making over time (project, planned operation). Based on the performed relevant predictive and optimization calculations for the conditions of the real object, the following three tasks have been accomplished. (1) The optimal pump module at the stage of operation for the existing polder drainage system has been substantiated. (2) The design of the pumping unit and the parameters of its components during the reconstruction of the polder drainage system have been improved. This made it possible to reduce the load on the pumping equipment, the duration of its operation, and the cost of electricity by 20–40%, depending on the water level of the year. The improvement was carried out by the diversion of the corresponding part of the surface runo with additionally introduced gravity elements in the form of a puncture in the body of the protective dam and a siphon intake. (3) We have substantiated the optimal water regulation technology for the existing polder drainage system in modern and forecast weather and climate conditions, which will ensure the maintenance of the necessary water-air regime of the drained soils in di erent phases of the growing season of agricultural crops. This will make it possible, on demand, to increase the energy and general environmental and economic e ciency during their creation and functioning of the polder drainage system in accordance with modern changing conditions.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2024-00022024-04-29T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2024-0001<abstract> <title style='display:none'>Abstract</title> <p>The shallow-water and multilayer hydrostatic models have been commonly used to analyze the problems of a sediment-laden, plane open-channel flow. The models are adequate to solve a quasi-hydrostatic flow problem, but their accuracy deteriorates as the e ects of the vertical acceleration gain in significance. Herein, a higher-order numerical model for treating the problems of unsteady, plane open-channel flow over a movable bed is proposed. In this model, the flow hydrodynamics is governed by the depth-averaged Boussinesq-type equations, and the bed morphodynamics is determined by an Exner-type equation and additional equations describing the non-equilibrium transports of suspended load and bed load. A hybrid finite-volume and finite-di erence scheme was used to discretize and solve the governing equations, yielding solutions that are in satisfactory agreement with the experimental data. Overall, the results of the proposed model for the temporal free-surface profile and bed evolution were fairly adequate. For the two particular cases considered, however, the quality of its results was moderately a ected by the e ects of the three-dimensional characteristics of the dam-break flow and the sliding of the dike body due to sub-surface flow. The results of this investigation highlight the importance of including a higher-order Boussinesq-type correction for refining sediment transport computations.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2024-00012024-02-19T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2023-0010<abstract> <title style='display:none'>Abstract</title> <p>The paper presents the results of theoretical studies on turbulent water motion in pipelines, obtained by the analysis of experimental data regarding hydraulic patterns of turbulent flows. The authors suggest to evaluate the relevant parameters on the basis of the molecular and turbulent viscosity indicators, with the introduction of the conditional relative thickness of the boundary layer on the pipeline walls into the calculations. On this basis, the authors specified semi-empirical relationships for the distribution of averaged velocities in the pipe cross-sections, and revealed new theoretical relationships between the main parameters of turbulent pipe flows. The research confirmed the adequacy of these relationships given the good agreement of the calculated averaged velocity values with the experimental data which formed a basis for the current standards for hydraulic calculations of water supply pipes. For hydraulically smooth pipes, the authors derived an explicit dependence of the hydraulic friction coe cient on the Reynolds number, which almost completely corresponds to the well-known Prandtl-Colebrook equation that has an implicit form. The presented research allowed to determine numerical values and analytical relationships between parameters, which enabled evaluating turbulent flows in hydraulically smooth pipes in a new way.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2023-00102024-01-20T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2023-0009<abstract> <title style='display:none'>Abstract</title> <p>In this study, the effectiveness of mineral pumice application in sewage treatment in the dairy industries was investigated, with various factors such as adsorbent dose, mixing speed, pH and contact time being studied in detail. The results obtained showed that mineral pumice in a granular form, with a contact time of 20 hours and a volume fraction of one third and pH of 8 has the ability to COD (Chemical Oxygen Demand) decreasing up to 56.9%. However, by using mineral pumice in powder form, in three cases considered, higher efficiency than for pumice granules has been observed. It seems that acidity conditions do not have a positive effect on this efficiency. As the contact time increased, the adsorption rate increased, mostly due to increased probability of collision with the adsorbent surface. With an increasing adsorbent dose, the absorption rate also increased, especially in the range of 15 g/l. Regarding the mixing speed, no definite conclusion can be drawn, because in some cases, with increasing mixing speed, the COD reduction efficiency decreased. Considering the use of mineral pumice in reducing COD, in accordance with to the obtained results, it is better to use mineral pumice in granular, rather than in powder, form.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2023-00092023-12-26T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2023-0008<abstract> <title style='display:none'>Abstract</title> <p>The environmental state of rice irrigation systems (RIS) is determined by many factors, including natural ones (soil, topographical, hydrogeological, and climatic factors) and technological ones (irrigation norm, design, and parameters of irrigation and drainage networks, etc). The most significant influence on the ecological reclamation state of the RIS carries is effected by its drainage network (DN). The need to maintain a flushing water regime with specific filtration rates to prevent secondary salinization in the Danube Delta’s rice systems is a crucial aspect of managing these agricultural areas. In the saline areas of rice systems located in the Danube Delta, the DN must ensure the maintenance of the flushing water regime with the rates of filtration ranging between 10 to 12 mm/day. This is a prerequisite for preventing secondary salinization of irrigated lands of these rice systems. According to the results of studies, the filtration from the surface of the irrigation checks of the Danube Delta RIS has been established, and its values in the area of the rice check vary significantly. Different intensity of filtration in the area of rice checks causes the difference in mineralization of groundwater and in the content of salts in the soil. This leads to the fact that the same rice check created various natural reclamation conditions and different productivity of cultivated crops.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2023-00082023-12-26T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2023-0007<abstract> <title style='display:none'>Abstract</title> <p>The provision of a reliable water-supply system is essential for the development and well-being of urban communities. Samdrupjongkhar Thromde, located in Bhutan, has been facing water supply challenges despite the presence of a water treatment plant. The non-perennial nature of the current water source coupled with malfunctions in water pumps has led to acute water shortages in the municipality. To address this issue, this study carried out a feasibility investigation and designed a gravity water supply system by conducting an EPANET (Environment Protection Agency Network Evaluation Tool) analysis. The study involved field visits to identify potential water sources, and a topo-graphic survey using RTK (Real Time Kinematics) technology to determine the optimal pipeline route. The EPANET analysis was then conducted to evaluate the hydraulic performance of the initial route. Based on these findings, a final water pipeline route was selected considering factors such as terrain characteristics, construction feasibility, avoidance of negative water pressure, and minimum encroachment of private land. The results showed that the maximum pressure head within the pipeline system reached 296 m with a maximum water flow velocity of 5 m/s. However, at the outlet, the pressure head decreased to 70 m and the velocity decreased to 2 m/s. Two Break Pressure Tanks (BPT) were strategically placed to achieve this pressure reduction. The chosen pipe materials and their placement ensure the long-term reliability and functionality of the water supply system, while considering maintenance convenience and terrain characteristics.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2023-00072023-10-16T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2023-0006<abstract> <title style='display:none'>Abstract</title> <p>Modern climatic changes, in particular, changes in the amount and intensity of soil moisture (precipitation regime), have a significant impact on the water-physical properties of mineral soils. The state of soil’s solid phase and the mutual arrangement of its structural particles can be considered as the most significant factor for soil properties. Due to the structure of the soil, it is possible to influence the uniformity of the distribution of water in the soil sample not only in the vertical direction, but, partially, also in the horizontal direction, which will allow to resolve the issue of local flooding of individual areas and the bearing capacity of mineral soils. For the analysis of changes in the water-physical properties of the soil environment, the soil was considered as a homogeneous in density and continuous environment formed by a set of separate structural aggregates connected by cohesive forces. Based on the experimental results of the physical modelling, it was determined that the presence of structural soil macroaggregates with a size of 4 to 6 mm is the most appropriate for slowing down the vertical filtration of water saturating the lower soil layers, and the formation of structural soil macroaggregates of size larger than 6 to 10 mm for the predominant types of soils is necessary to increase the vertical filtration. Due to the size of the formed macroaggregates, it is possible to predict a change in the water-physical parameters of the soil, which then can be used for the assessment of the calculated characteristics of the soil environment.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2023-00062023-08-21T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2023-0005<abstract> <title style='display:none'>Abstract</title> <p>Intensification of extreme rainfall-runo events in arid and semi-arid regions because of climate change induce the water erosion that contributes considerably to the loss of vegetal layers of soils and reduce the storage capacity of dams by silting of transported sediments from the watershed to the impoundment. This paper aims at proposing means for protecting the Mghila dam against silting by identification and delimitation of vulnerable areas to water erosion. This dam, built in the North-West of Algeria, ensures irrigated cultivation. Topographical, geological, and land use characteristics of the watershed were analyzed using the geographic information system (GIS). Analysis of results has allowed the identification by area percentage four-vulnerability classes with sensitivity to the water erosion: low(18.89%), medium (13.08%), high (65.05%) and very high (8.38%). The spatial distribution of the lithological substratum friability, the vegetation cover and slope degrees have led to the development of an e cient strategy for the watershed management in order to reduce the e ect of water erosion on soil degradation and silting of the Mghila dam.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2023-00052023-07-05T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2023-0001<abstract> <title style='display:none'>Abstract</title> <p>Subcritical flows over highway and railway embankments, commonly encountered during flood events, can be treated like submerged flows over trapezoidal-shaped weirs. In earlier studies, the equation of the submerged-flow discharge for such types of weirs was developed as a function of the degree of submergence and free-flow discharge. However, the application of this equation in practice requires a pre-determined discharge from experiments performed under free-flowconditions. In this study, a discharge equation was deduced from the streamwise momentum balance equation, which overcomes the drawback of the previous approaches. The results of the validation demonstrated that the proposed equation is capable of predicting the submerged-flow discharge of a trapezoidal-shaped weir within ±6.0% of the measured value. Furthermore, the most prominent features of the submerged overflows were examined by systematically analyzing the experimental data. For such flows, the free-surface and bed-pressure profiles are self-similar only over the upstream face of the weir. Results of this investigation confirmed that the degree of submergence and the slope of the downstream weir face significantly affect the characteristics of the submerged flow, but the effect of the latter on the non-modular discharge is marginal.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2023-00012023-03-08T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2023-0003<abstract> <title style='display:none'>Abstract</title> <p>Seismic analysis of a fractured dam is a generally complex problem. This paper presents an earthquake behavior investigation of a fractured concrete gravity dam considering dam-reservoir--foundation rock interaction. The Koyna dam profile, located in India, is adopted in this study. The nonlinear finite element analyses are conducted taking into account empty and full reservoir cases, to exhibit the hydrodynamic e ect of reservoir water on the dam earthquake response. The hydrodynamic pressure is modeled by fluid finite elements based on a Lagrangian approach. Transient analyses take into account material and connection nonlinearity. Drucker-Prager model is employed in nonlinear analyses for the dam concrete and foundation rock. The structural crack between the top and bottom blocks of the dam is presented by surface-to-surface contact elements based on Coulomb’s friction law in order to simulate the behavior of contact joints and deformation of blocks. The distribution of horizontal displacements and principal stresses along the dam height is investigated for empty and full reservoir cases.The failure processes of two potential failure modes of cracked dam, i.e, the separation and sliding of top block during an earthquake, are examined.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2023-00032023-05-15T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2023-0002<abstract> <title style='display:none'>Abstract</title> <p>In providing clean water services to a community, a clean water supply distribution network system is very important. This study is aimed at the determination of the distribution pipe network by simulating and optimizing the water supply system in the Arjawinangun area, Cirebon, West Java, Indonesia. The data collected was analyzed by using EPANET 2.0 software for modelling water distribution systems. The results show that the total domestic and non-domestic water demand is 391.41 l/s, with a leakage rate of 20%. The pipeline installation plan for the Arjawinangun area is planned to be installed for a length of 23,045 m, with pipe diameters ranging from 400 to 90 mm. The Arjawinangun Area O take Reservoir drainage system, which is at an elevation of +25 m above sea level, requires a distribution pump with a head (H) of 6.0 bar. Also, using the gravity distribution technique, a water tower can be built (~ 55 m) as a water supply booster pump.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2023-00022023-05-15T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2023-0004<abstract> <title style='display:none'>Abstract</title> <p>Computational examinations of the flow field in an open channel having a single Backward--Facing Step (BFS) with a constant water depth of 1.5 m were performed. The e ects of the expansion ratio, and the flow velocity along the reattachment length, were investigated by employing two di erent expansion ratios of 1.5 and 2, and eight various flow velocities of 0.5, 1, 2, 3, 4, 5, 7.5 and 10 m/sec in the Computational Fluid Dynamic (CFD) simulations. Commercially available CFD software, ANSYS FLUENT, was used for calculations. The simulation outcomes were verified using experimental results. Moreover, analyses were performed by using two equation turbulence closure models, K-ɛ family (standard, RNG and realizable), and K-ω family (Wilcox’s and SST K-ω). The analyses have revealed that the reattachment length increases with an increase in the expansion ratio, the flow velocity and the Reynolds number. The results obtained for two expansion rates and eight di erent flow velocities have shown insignificant di erences between one turbulence closure model and the others. Furthermore, it was observed that both velocity and expansion ratios have an e ect on the reattachment zone size.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2023-00042023-05-15T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2022-0002<abstract> <title style='display:none'>Abstract</title> <p>The waste warm waters from power plants, owing to their temperature regime (25–38°C) and the volumes of discharge, allow for their use for heating of open ground areas in agriculture. Underground heating by such water is a new, special heat and irrigation method which enables not only purposeful regulation of temperature conditions of the crop growing environment, but also dissipates heat in the soil, thus cooling the water for its reuse. This makes it possible to reduce the thermal pollution of water sources.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2022-00022022-06-06T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2022-0006<abstract> <title style='display:none'>Abstract</title> <p>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.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2022-00062023-02-17T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2022-0001<abstract> <title style='display:none'>Abstract</title> <p>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.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2022-00012022-05-22T00:00:00.000+00:00https://sciendo.com/article/10.2478/heem-2022-0003<abstract> <title style='display:none'>Abstract</title> <p>The non-uniformity of the flow velocity distribution in each section of compound channels and in the main channel-floodplain interface area causes errors in estimating water surface profile, flood routing, pollution transfer, and so on. To reduce the impacts of non-uniformity on the exact calculation of kinetic energy and momentum, <italic>α</italic> and <italic>β</italic> correction coefficients are used, respectively. However, the determination method of these coefficients is a challenging issue in river engineering. This study used the OpenFOAM Software to determine these coefficients numerically for two laboratory models of compound open channels of which the data are available, using the single-phase pimpleFoam solver to do modeling in the mentioned software and the k-<italic>ω</italic>SST turbulence model to calculate the flow characteristics. Based on the results, the highest difference (13%) between the results estimated by the software and those obtained from the lab experiments was seen in the low flow depth where the flow left the main channel and entered the floodplain of a very shallow depth, possibly due to the grid generation of this area. This difference decreased as the flow depth increased, and its average was 6.65% for <italic>α</italic> coefficient and 2.32% for <italic>β</italic> coefficient in all cases, which means the results of numerical modeling and the experimental data conformed well, and the OpenFOAM software can be successfully used in flow modeling and analyzing flow characteristics in compound channels.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/heem-2022-00032022-06-06T00:00:00.000+00:00en-us-1