<abstract><title style='display:none'>Abstract</title>The outlet flow velocity in the end section of the culvert barrel depends in most cases on the culvert geometry, including the barrel slope, as well as on upstream and downstream channel parameters. Flowing water can create pressure flow or free surface flow in the culvert barrel. In the case of an unsubmerged barrel outlet, the free-surface flow is more frequent than the full flow. Increased velocities can cause channel bed scour and bank erosion downstream of the culvert outlet. Different culvert flow cases in which the barrel outlet is unsubmerged are presented in this paper. The influence of the flow regime on the outlet velocity is also discussed.</abstract>

Outlet Flow Velocity in Circular Culvert

<abstract><title style='display:none'>Abstract</title>The aim of this paper was to analyze theoretical aspects of calculating steady water flow through unsubmerged circular orifices. Theoretical analysis shows that the values of discharge obtained by using formulas intended for small orifices are greater than those calculated using formulas for large orifices. These differences attain a maximum value when the water level reaches the upper edge of the orifice, and decrease when water head increases. It has been proven that the volumetric flow rate for circular unsubmerged orifices can be calculated by formulas for small orifices when the water level above the center of gravity is at least four times as high as the diameter of the orifice.</abstract>

Assessment of Equivalence of Small and Large Orifice Computational Models

<abstract>
<title style='display:none'>Abstract</title>
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.
</abstract>

Simulation of Pipe Networks Using EPANET to Optimize Water Supply: A Case Study for Arjawinangun Area, Indonesia

<abstract><title style='display:none'>Abstract</title> Drainage plays an extremely important role in hydraulic structures, such as earth dams. Observations of drainage in hydraulic structures under various soil conditions indicate that the phenomenon of clogging can lead to a radical reduction in the efficiency of drainage, making it non-functional within a few years after construction. This article describes the problems of drainage clogging by iron oxide in the examples of the Żur and Podgaje dams.</abstract>

Problem of Clogging in Drainage Systems in the Examples of the Żur and Podgaje Dams

<abstract><title style='display:none'>Abstract</title> Today, intensive urban development calls for new technologies in the field of environmental engineering. Extensive infrastructure requires more roads and motorways, as well as larger areas covered with concrete, which altogether leads to greater volumes ofwater creating surface run-off. Rotational separators, besides lamella and coalescence units, may provide a highly efficient method for treatment of storm water running off roads and motorways. This paper is focused on two important aspects of the operation of rotational separators: forces acting on a particle in liquid flow, and pressure distribution in the chamber. The resulting relations constitute crucial elements in the future method of designing such devices.</abstract>

Specification of forces in rotational separator

<abstract><title style='display:none'>Abstract</title> The paper focuses mainly on laboratory investigations of transient and transcritical flow in a single pipe of a sewer system. The aim of this paper is to present a comparison between pressure values calculated by an improved McCormack scheme and those measured at the hydraulic laboratory of the Gdańsk University of Technology, which were observed inside a pipe in an experiment for water flow with pressurization. The analysis proves that the numerical approach applied to flow simulation is a sufficiently accurate and reliable technique for predicting the basic parameters of storm sewer flow</abstract>

Experimental Verification of Storm Sewer Transient Flow Simulation

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<title style='display:none'>Abstract</title>
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.
</abstract>

Analysis of Pluviograms Recorded in the Area of a Phosphogypsum Heap at Wiślinka, Poland

<abstract>
<title style='display:none'>Abstract</title>
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.
</abstract>

Justification of Technological and Design Parameters of Polder Drainage Systems by an Optimization Approach

<abstract>
<title style='display:none'>Abstract</title>
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.
</abstract>

Numerical Modeling of Sediment Transport and Bed Evolution in Nonuniform Open-Channel Flows

<abstract>
<title style='display:none'>Abstract</title>
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.
</abstract>

Theoretical Aspects of Turbulent Flows in Pipeline

<abstract>
<title style='display:none'>Abstract</title>
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.
</abstract>

Formation of a Favorable Filtration Regime of Soils in Saline Areas of the Danube Delta Rice Irrigation Systems

<abstract>
<title style='display:none'>Abstract</title>
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.
</abstract>

Mineral Pumice Efficiency in Wastewater Treatment in Dairy Industries

<abstract><title style='display:none'>Abstract</title> The knowledge of transient flow in pressure pipelines is very important for the designing and describing of pressure networks. The water hammer is the most common example of transient flow in pressure pipelines. During this phenomenon, the transformation of kinetic energy into pressure energy causes significant changes in pressure, which can lead to serious problems in the management of pressure networks. The phenomenon is very complex, and a large number of different factors influence its course. In the case of a water hammer caused by valve closing, the characteristic of gate closure is one of the most important factors. However, this factor is rarely investigated. In this paper, the results of physical experiments with water hammer in steel and PE pipelines are described and analyzed. For each water hammer, characteristics of pressure change and valve closing were recorded. The measurements were compared with the results of calculations perfomed by common methods used by engineers - Michaud’s equation and Wood and Jones’s method. The comparison revealed very significant differences between the results of calculations and the results of experiments. In addition, it was shown that, the characteristic of butterfly valve closure has a significant influence on water hammer, which should be taken into account in analyzing this phenomenon. Comparison of the results of experiments with the results of calculations? may lead to new, improved calculation methods and to new methods to describe transient flow.</abstract>

An Analysis of the Impact of Valve Closure Time on the Course of Water Hammer

<abstract><title style='display:none'>Abstract</title> A two-dimensional numerical model was used for a simulation of vertical average longshore currents generated by both wind friction and wind-wave action in the nearshore zone. The modelling domain includes the southern part of the Baltic Proper (all boundaries were closed). Wind, uniform in space and varying in time, was the only forcing in the model. The correlation coefficient higher than 0.8 was obtained by model calibration versus the field measurements of currents conducted at the Lubiatowo field station (southern Baltic) during about 1.5 months in 2006. Comparative simulations of total currents including both wind-induced drift and wave components, and of total currents including only a wind-induced drift component, showed that the input of the drift component into currents in the nearshore zone is greater than commonly believed.Wind-induced drift strongly dominates outside the zone of wave transformation, and its input into the total resulting currents remains noticeable even in a zone between the shoreline and the depth of the first wave breaking. Thus, wind-induced drift constitutes up to 50% of the resulting longshore currents for longshore winds and no less than 20% of the longshore component of currents for winds at 45 degrees to the longshore direction.</abstract>

Wind Influence on the Formation of Nearshore Currents in the Southern Baltic: Numerical Modelling Results

<abstract>
<title style='display:none'>Abstract</title>
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.
</abstract>

Artificial Neural Network for Estimation of Local Scour Depth Around Bridge Piers

<abstract><title style='display:none'>Abstract</title>A small-scale model experiment on the pull-out resistance of suction caissons is described. The pull-out force and suction developed within the caisson in the extraction process were recorded during the experiment. A simple breakout model, together with an elementary static formulae, is applied to predict the results obtained experimentally. There is a reasonably good agreement between the experimental results and predictions. An extensive discussion of the approach applied is included. The analysis presented in this paper is original, as it differs from other approaches mentioned in this paper, and leads to acceptable predictions. At the end, the results are also compared with another approach for predicting the capacity of suction caissons.</abstract>

The Pull-out Capacity of Suction Caissons in Model Investigations

<abstract><title style='display:none'>Abstract</title>The paper presents results of field and theoretical investigations of a natural sandy shore located near the IBW PAN Coastal Research Station in Lubiatowo (Poland, the south Baltic Sea). The study site displays multi-bar cross-shore profiles that intensively dissipate wave energy, mostly by breaking. The main field data comprise offshore wave parameters and three cross-shore bathymetric profiles. Waveinduced nearbed velocities and bed shear stresses are theoretically modelled for weak, moderate, strong and extreme storm conditions to determine sediment motion regimes at various locations on the seaward boundary of the surf zone. The paper contains a discussion on the depth of closure concept, according to which the offshore range of sea bottom changes can be determined by the extreme seasonal deep-water wave parameters.</abstract>

Wave-Induced Sediment Motion Beyond the Surf Zone: Case Study of Lubiatowo (Poland)

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 Archives of Hydro-Engineering and Environmental Mechanics (formerly Archives of Hydro-Engineering and Archiwum...