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Drainage modeling that accurately captures urban storm inundation serves as the foundation for flood warning and drainage scheduling. In this paper, we proposed a novel coupling ideology that, by integrating 2D-1D and 1D-2D unidirectional processes, overcomes the drawback of the conventional unidirectional coupling approach that fails to properly represent the rainfall surface catchment dynamics, and provides more coherent hydrological implications compared to the bidirectional coupling concept. This paper first referred to a laboratory experimental case from the literature, applied and analyzed the coupling scheme proposed in this paper and the bidirectional coupling scheme that has been widely studied in recent years, compared the two coupling solutions in terms of the resulting accuracy and applicability, and discussed their respective strengths and weaknesses to validate the reliability of the proposed method. The verified proposed coupling scheme was then applied to the modeling of a real drainage system in a region of Nanjing, China, and the results proved that the coupling mechanism proposed in this study is of practical application value. HIGHLIGHTS A novel coupling approach by combining two unidirectional processes.; Comparison with bidirectional tight coupling scheme in terms of simulation accuracy and applicability.; The proposed coupling idea provides reliable outcomes with enhanced applicability.;

Abstract This paper presents a topology optimization approach for the surface flows on variable design domains. Via this approach, the matching between the pattern of a surface flow and the 2-manifold used to define the pattern can be optimized, where the 2-manifold is implicitly defined on another fixed 2-manifold named as the base manifold. The fiber bundle topology optimization approach is developed based on the description of the topological structure of the surface flow by using the differential geometry concept of the fiber bundle. The material distribution method is used to achieve the evolution of the pattern of the surface flow. The evolution of the implicit 2-manifold is realized via a homeomorphous map. The design variable of the pattern of the surface flow and that of the implicit 2-manifold are regularized by two sequentially implemented surface-PDE filters. The two surface-PDE filters are coupled, because they are defined on the implicit 2-manifold and base manifold, respectively. The surface Navier-Stokes equations, defined on the implicit 2-manifold, are used to describe the surface flow. The fiber bundle topology optimization problem is analyzed using the continuous adjoint method implemented on the first-order Sobolev space. Several numerical examples have been provided to demonstrate this approach, where the combination of the viscous dissipation and pressure drop is used as the design objective.

This paper presents a topology optimization approach for the surface flows on variable design domains. Via this approach, the matching between the pattern of a surface flow and the 2-manifold used to define the pattern can be optimized, where the 2-manifold is implicitly defined on another fixed 2-manifold named as the base manifold. The fiber bundle topology optimization approach is developed based on the description of the topological structure of the surface flow by using the differential geometry concept of the fiber bundle. The material distribution method is used to achieve the evolution of the pattern of the surface flow. The evolution of the implicit 2-manifold is realized via a homeomorphous map. The design variable of the pattern of the surface flow and that of the implicit 2-manifold are regularized by two sequentially implemented surface-PDE filters. The two surface-PDE filters are coupled, because they are defined on the implicit 2-manifold and base manifold, respectively. The surface Navier-Stokes equations, defined on the implicit 2-manifold, are used to describe the surface flow. The fiber bundle topology optimization problem is analyzed using the continuous adjoint method implemented on the first-order Sobolev space. Several numerical examples have been provided to demonstrate this approach, where the combination of the viscous dissipation and pressure drop is used as the design objective. [ABSTRACT FROM AUTHOR]

Measurements of mass flow through a three-outlet spillway modeled after a scaled-down spillway were conducted. The inlet and channel leading up to the outlets were placed to lead the water toward the outlet at an angle. With this, measurements of the water level at three locations were recorded by magnetostrictive sensors. The volumetric flow rates for each individual outlet were recorded separately to study the differences between them. Additionally, Acoustic Doppler Velocimetry was used to measure water velocities close to the outlets. The conditions changed were the inlet volume flow rate and the flow distribution was measured at 90, 100, 110, and 200 L per second. Differences between the outlets were mostly within the error margin of the instruments used in the experiments with larger differences shown for the 200 L test. The results produced together with a CAD model of the setup can be used for verification of CFD methods. A simulation with the k-epsilon turbulence model is included and compared to earlier experiments and the new experimental results. Larger differences are seen in the new experiments. Differing inlet conditions are assumed as the principal cause for the differences seen. [ABSTRACT FROM AUTHOR]

Urban flooding is a problem faced by most countries because of climate change. Without storm drainage systems, negative impacts may occur, such as traffic problems and increasing groundwater levels, especially in lowlands. The implementation of storm drainage networks and their fittings in poor countries is affecting their economic development. Therefore, improving the efficiency of the storm drainage network is an important issue that should be considered. This paper aims to study the most appropriate position or arrangements of grate inlets to upgrade drainage efficiency at less cost. Different arrangements of grates were studied and their efficiency was determined. A comparison between the total grate's efficiency was conducted and the best arrangement was selected. Additionally, a dimensional analysis equation was developed to determine the total efficiency of the system. Finally, the FLOW-3D program was used to simulate the laboratory results using different discharges and numbers of inlets. The error of calculation ranged between 5% and 8%. Therefore, the results indicated that this program is a powerful tool for predicting the discharge efficiency and velocity direction for large discharges. A comparison was made between this study and previous studies. The results indicated that the same trend existed. A new equation was developed to correlate discharge efficiency (E) with relative total discharge Q and number of inlets. The equation can be used by planning engineers to conduct initial planning of storm drainage layout systems and achieve cost saving. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Babylon Center for Humanities Studies is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Measurements of mass flow through a three-outlet spillway modeled after a scaled-down spillway were conducted. The inlet and channel leading up to the outlets were placed to lead the water toward the outlet at an angle. With this, measurements of the water level at three locations were recorded by magnetostrictive sensors. The volumetric flow rates for each individual outlet were recorded separately to study the differences between them. Additionally, Acoustic Doppler Velocimetry was used to measure water velocities close to the outlets. The conditions changed were the inlet volume flow rate and the flow distribution was measured at 90, 100, 110, and 200 L per second. Differences between the outlets were mostly within the error margin of the instruments used in the experiments with larger differences shown for the 200 L test. The results produced together with a CAD model of the setup can be used for verification of CFD methods. A simulation with the k-epsilon turbulence model is included and compared to earlier experiments and the new experimental results. Larger differences are seen in the new experiments. Differing inlet conditions are assumed as the principal cause for the differences seen.

Copyright of COMU Journal of Agriculture Faculty / ÇOMÜ Ziraat Fakültesi Dergisi is the property of Canakkale Onsekiz Mart University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Surface flow (SF) and subsurface flow (SSF) are important hydrological processes occurring on slopes, and are driven by two main factors: rainfall intensity and slope gradient. To explore nitrogen (N) migration and loss from sloping farmland in the Miyun Reservoir, the characteristics of total nitrogen (TN) migration and loss via SF and SSF under different rainfall intensities (30, 40, 50, 60, 70, and 80 mm/h) and slope gradients (5°, 10°, and 15°) were studied using indoor stimulated rainfall tests and mathematical models. Nitrogen loss via SF and SSF was found to increase exponentially and linearly with time, respectively, with SSF showing 14–78 times higher loss than SF. Under different rainfall intensities, SSF generally had larger TN loss loading than SF, thereby indicating that SSF was the main route for TN loss. However, the TN loss loading proportion via SF increasing from 14.03% to 35.82% with increasing rainfall intensity is noteworthy. Furthermore, compared with the measurement data, the precision evaluation index Nash-Suttcliffe efficient (NSE) and the determination coefficient (R2) of the effective mixing depth model in the numerical simulation of TN loss through SF in the sloping farmland in the Miyun Reservoir were 0.74 and 0.831, respectively, whereas those of the convection-dispersion equation for SSF were 0.81 and 0.811, respectively, thus indicating good simulation results. Therefore, this paper provides a reference for studying the mechanism of N migration and loss in sloping farmland in the Miyun Reservoir. [ABSTRACT FROM AUTHOR]

Architects aspire to build iconic buildings and focus on experimenting with non-standard forms. The construction of non-standard forms is challenging. This has led many researchers and facade designers to develop and resolve the complexity of forms to simpler, buildable elements. In this progress, the tessellation of non-standard surfaces has experimented considerably with different approaches using computational tools. All the approaches from researchers or facade engineers have limited access for every designer. As they develop patented software or use any coding languages which are not accessed by any open-source platform. Hence in academia, it is difficult to experiment in this domain. This paper analyzes the existing panalization computational tools and different approaches used by researchers worldwide in developing complex curved surfaces. Analyzing the relevant cases led to identifying the gap in current research. This has led to investigate and explore a new algorithmic process using an existing computational tool: Agent-based modeling on an open-source tool (Grasshopper-Visual programming language), which is phase -1 of the Master's thesis. [ABSTRACT FROM AUTHOR]

Many fundamental biological processes are dependent on cellular migration. Although the mechanical mechanisms of single-cell migration are relatively well understood, those underlying migration of multiple cells adhered to each other in a cluster, referred to as cluster migration, are poorly understood. A key reason for this knowledge gap is that many forces—including contraction forces from actomyosin networks, hydrostatic pressure from the cytosol, frictional forces from the substrate, and forces from adjacent cells—contribute to cell cluster movement, making it challenging to model, and ultimately elucidate, the final result of these forces. This paper describes a two-dimensional cell membrane model that represents cells on a substrate with polygons and expresses various mechanical forces on the cell surface, keeping these forces balanced at all times by neglecting cell inertia. The model is discrete but equivalent to a continuous model if appropriate replacement rules for cell surface segments are chosen. When cells are given a polarity, expressed by a direction-dependent surface tension reflecting the location dependence of contraction and adhesion on a cell boundary, the cell surface begins to flow from front to rear as a result of force balance. This flow produces unidirectional cell movement, not only for a single cell but also for multiple cells in a cluster, with migration speeds that coincide with analytical results from a continuous model. Further, if the direction of cell polarity is tilted with respect to the cluster center, surface flow induces cell cluster rotation. The reason why this model moves while keeping force balance on cell surface (i.e., under no net forces from outside) is because of the implicit inflow and outflow of cell surface components through the inside of the cell. An analytical formula connecting cell migration speed and turnover rate of cell surface components is presented.

Urban flooding is a problem faced by most countries because of climate change. Without storm drainage systems, negative impacts may occur, such as traffic problems and increasing groundwater levels, especially in lowlands. The implementation of storm drainage networks and their fittings in poor countries is affecting their economic development. Therefore, improving the efficiency of the storm drainage network is an important issue that should be considered. This paper aims to study the most appropriate position or arrangements of grate inlets to upgrade drainage efficiency at less cost. Different arrangements of grates were studied and their efficiency was determined. A comparison between the total grate’s efficiency was conducted and the best arrangement was selected. Additionally, a dimensional analysis equation was developed to determine the total efficiency of the system. Finally, the FLOW-3D program was used to simulate the laboratory results using different discharges and numbers of inlets. The error of calculation ranged between 5% and 8%. Therefore, the results indicated that this program is a powerful tool for predicting the discharge efficiency and velocity direction for large discharges. A comparison was made between this study and previous studies. The results indicated that the same trend existed. A new equation was developed to correlate discharge efficiency (E) with relative total discharge Q and number of inlets. The equation can be used by planning engineers to conduct initial planning of storm drainage layout systems and achieve cost saving.

Investigation of floods as one of the most common natural destructive phenomena is very important. Due to the problem of deficiency and defect of hydraulic data in most hydrometric stations in the country, flood hydrograph simulation by hydrological and hydraulic models is helpful. There are several hydrological and hydraulic models to simulate flood hydrographs. The present study has investigated the performance of Advection-Diffusion relationships of 36 flood phenomena in 5 study reaches of Kashkan river and its tributary. Physical properties related to the studied periods and hydrometery data related to each flood phenomenon, including discharge and scale of the input and output station, were used to determine the Manning roughness coefficient and flood simulation. Evaluation of obtained hydrographs indicates the acceptable accuracy of the model in term of simulating values of flood trends and discharge. In order to evaluate the accuracy of the model results, different coefficients such as: Nash-Sutcliffe, RMSE, Volumetric Efficiency, Kling-Gupta and R correlation coefficient were calculated. A value above 0.5 for the Nash-Sutcliffe coefficient in 29 flood phenomena out of 36 studied phenomena, and an acceptable range of other coefficients for all studied flood phenomena, indicates the verifiable results of flood hydrograph simulation using simplified propagation methods at reach scale for studied watershed. Therefore, Advection-Diffusion relationships can be used in similar watersheds to the study area to simulate floods.

Introduction: The underground drainage-pipe network is one of the vital components of a modern city, and it plays an important role in preventing or mitigating urban flooding. Thus, pipe network data are necessary for simulation of the entire urban rainfall–runoff process. However, pipe network data are sparse or unavailable in most urban areas.Methods: To solve this problem, we developed a novel approximation method that can be used calculate the drainage capacity of the pipe system. This method is named the road-drainage method, and it works under the assumption that the pipe network functions by subtracting the corresponding mass from the water conservation equation only from areas of road. The mass is determined from weir flow formulas together with the road properties and correction for this mass is applied to the rainfall source term.Results: Two test cases were used to compare the performance of the new method with an existing method, under which mass is subtracted from the entire area during the rainfall–runoff process. The results showed that the new method considerably improves the accuracy of simulated peak volume, with an improvement of 2.62%–58.75% compared with the existing method across various scenarios. Moreover, the proposed new method reduces the time shift of the rise and peak of surface inundation by 10–45 min in various scenarios, which reflects a more realistic model of the rainfall–runoff process.Discussion: These results demonstrate that the proposed new method can represent the drainage capability more accurately and is more consistent with reality. The road-drainage method has promising potential for application in urban flood simulation in areas without drainage system data and for the support of large-scale urban hydrologic modeling.

We consider the governing equations for the motion of the viscous fluids in two moving domains and an evolving surface from both energetic and thermodynamic points of view. We make mathematical models for multiphase flow with surface flow by our energetic variational and thermodynamic approaches. More precisely, we apply our energy densities, the first law of thermodynamics, and the law of conservation of total energy to derive our multiphase flow system with surface tension and flow. We study the conservative forms and conservation laws of our system by using the surface transport theorem and integration by parts. Moreover, we investigate the enthalpy, the entropy, the Helmholtz free energy, and the Gibbs free energy of our model by applying the thermodynamic identity. The key idea of deriving surface tension and viscosities is to make use of both the first law of thermodynamics and our energy densities. [ABSTRACT FROM AUTHOR]

The Long-time behavior of orbits is one of the most fundamental properties in dynamical systems. Poincaré studied the Poisson stability, which satisfies a time-reversal symmetric condition, to capture the property of whether points return arbitrarily near the initial positions after a sufficiently long time. Birkhoff introduced and studied the concept of non-wandering points, which is one of the time-reversal symmetric conditions. Moreover, minimality and pointwise periodicity satisfy the time-reversal symmetric condition for limit sets. This paper characterizes flows with the time-reversal symmetric condition for limit sets, which refine the characterization of irrational or Denjoy flows by Athanassopoulos. Using the description, we construct flows on a sphere with Lakes of Wada attractors and with an arbitrarily large number of complementary domains, which are flow versions of such examples of spherical homeomorphisms constructed by Boroński, Činč, and Liu. [ABSTRACT FROM AUTHOR]

Runoff generated by heavy rainfall in natural catchment area and caused by ditch clogging in artificial structure increases the instability of the slope. The effects of runoff are usually neglected in traditional rainfall-induced slope failure analysis. In order to consider the effects of runoff on the slope instability, this study attempts to simulate the runoff, infiltration and slope instabilities simultaneously on both wide/narrow area. For this purpose, this study firstly proposes a coupled model of surface flow, subsurface flow, and soil mechanics based on Diffusion wave equations, Richards’s equation, Green-Ampt infiltration capacity model, and local factor of safety approach in wide area simulation. Next, snowmelt and surface grass layer are additionally considered in narrow area simulation. Finally, the proposed coupled model is applied to two slopes at Nissho Pass and Kuromatsunai in Hokkaido, Japan. The slope instabilities assessment approach provides an effective method for simulating runoff and slope instabilities. In wide area, the distribution map of the factor of safety has significant implications for precisely determining the dangerous spots and accurately releasing the warning information. In narrow area, the slope disaster points caused by the ditch clogging are extracted and effect of grass layer on slope stability assessment is demonstrated. The construction and maintenance of the drainage system can be re-designed to ensure all the surface flow caused by the precipitation drain out smoothly.

This study presents a hybrid Finite Volume – Finite Element (FV-FE) model that describes the coupled surface-subsurface flow processes occurring during furrow irrigation and fertigation. The numerical approach combines a one-dimensional description of water flow and solute transport in an open channel with a two-dimensional description of water flow and solute transport in a subsurface soil domain, thus reducing the dimensionality of the problem and the computational cost. The modeling framework includes the widely used hydrological model, HYDRUS, which can simulate the movement of water and solutes, as well as root water and nutrient uptake in variably-saturated soils. The robustness of the proposed model was examined and confirmed by mesh and time step sensitivity analyses. The model was theoretically validated by comparison with simulations conducted with the well-established model WinSRFR and experimentally validated by comparison with field-measured data from a furrow fertigation experiment conducted in the US.

The coupled role of seepage and surface flow on bank retreat has long been neglected, partly due to the concealment and complexity of seepage erosion. To fill this gap, we set up a three-dimensional laboratory experiment to explore bank retreat process in response to seepage and surface flow. During each experiment, we measured the changes of total soil stress, matric suction, and water content within the bank, as well as flow velocity and suspended sediment concentration near the bank. Results show that a rapid decrease in matric suction, the bank toe undercutting consequent to seepage erosion, the formation of tension crack on the bank top, and the occurrence of toppling or shear failure is the typical sequence of the observed bank retreat process under seepage flow. The inclusion of surface flow erodes slump blocks and so promotes cantilever formation, leading to additional bank failure. Compared with the case where only seepage is considered, the frequency of toppling failure under the coupled effect of seepage and surface flow decreases, but the contribution to the bank retreat increases by 37 %. The time taken to collapse in three-dimensional experiments is at least 1.5 h earlier than that of two-dimensional experiments, indicating the importance of preferential flow pathways of seepage. Overall, this research illustrates how surface flow interacts with seepage flow to control bank retreat process and is indeed a first step toward a fully understanding of multifactor-driven bank retreat.

This article refers to the problem of the formation of oxide films during induction melting. The mutual influence of the forced convection of the melt in an alternating electromagnetic field and the elastic-stress state of the dielectric film on the surface are considered. The assumptions of the mathematical model, governing equations and film properties are discussed in detail. The mechanisms that can create mechanical stresses in the film are considered, and it is shown that the greatest contribution to stresses comes from viscous forces arising from the movement of the melt under the film. The influence of electromagnetic field frequency (its non-dimensional analogue) on melt flows is investigated numerically, it is shown how these flows deform films of different configurations. It was found that there are ranges of parameters, such as the frequency of the magnetic field (and its spatial distribution), at which films of certain sizes are in stable equilibrium. On the plane of parameters frequency and film size the maps of film deformation are plotted, from which one can see favourable and unfavourable regimes in terms of formation and stability of the surface dielectric films. [ABSTRACT FROM AUTHOR]

The combined effects of transient, surface and subsurface flows and infiltration govern the rainfall-induced potential failure of unsaturated soil slopes stabilised by matric suction. In this paper, it is shown how fundamental fluid dynamics can be employed to closely model the above flow effects than the empirical Richard's approach. The fluid dynamics-based Navier-Stokes formulation also facilitates the integration of the three modes of flow: (1) surface, (2) subsurface and (3) infiltration water flows, into a unified analytical model. Therefore, in contrast to previous studies, this fundamental approach can seamlessly incorporate the effects of continuous interplay between surface and subsurface water flows and the inertial terms of flow on the reduction of matric suction in unsaturated soils. Transient flow effects have been combined with geomechanics of unsaturated soil to demonstrate their impact on the stability of an embankment under a more realistic non-uniform rainfall. The innovative use of the laboratory-evaluated soil properties such as the hydraulic conductivity and porosity to express the drag force in the Navier-Stokes equations facilitates the examination of the sensitivity of slope stability to the relevant soil classification parameters. [ABSTRACT FROM AUTHOR]

Surface flow (SF) and subsurface flow (SSF) are important hydrological processes occurring on slopes, and are driven by two main factors: rainfall intensity and slope gradient. To explore nitrogen (N) migration and loss from sloping farmland in the Miyun Reservoir, the characteristics of total nitrogen (TN) migration and loss via SF and SSF under different rainfall intensities (30, 40, 50, 60, 70, and 80 mm/h) and slope gradients (5°, 10°, and 15°) were studied using indoor stimulated rainfall tests and mathematical models. Nitrogen loss via SF and SSF was found to increase exponentially and linearly with time, respectively, with SSF showing 14–78 times higher loss than SF. Under different rainfall intensities, SSF generally had larger TN loss loading than SF, thereby indicating that SSF was the main route for TN loss. However, the TN loss loading proportion via SF increasing from 14.03% to 35.82% with increasing rainfall intensity is noteworthy. Furthermore, compared with the measurement data, the precision evaluation index Nash-Suttcliffe efficient (NSE) and the determination coefficient (R2) of the effective mixing depth model in the numerical simulation of TN loss through SF in the sloping farmland in the Miyun Reservoir were 0.74 and 0.831, respectively, whereas those of the convection-dispersion equation for SSF were 0.81 and 0.811, respectively, thus indicating good simulation results. Therefore, this paper provides a reference for studying the mechanism of N migration and loss in sloping farmland in the Miyun Reservoir.

In gravity irrigation, how water is distributed in the soil profile makes it necessary to study and develop methodologies to model the process of water infiltration and redistribution. In this work, a model is shown to simulate the advancing front in border irrigation based on the one dimensional equations of Barré de Saint-Venant for the surface flow and the equation of Green and Ampt for the flow in a porous medium. The solutions were obtained numerically using a finite difference Lagrangian scheme for the surface flow and the Raphson method for the subsurface flow. The model was validated with data obtained from the literature from an irrigation test and its predictive capacity was compared with another model and showed excellent results. The hydrodynamic parameters of the soil, necessary to obtain the optimal irrigation discharge, were obtained through the solution of the inverse problem using the Levenberg–Marquardt optimization algorithm. Finally, the results found here allow us to recommend that this model be used to design and model border irrigation, since the infiltration equation uses characteristic parameters of the physical soil. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study area comprises of humid and undifferentiated highland climates having total precipitation of 52inches (1320mm) and fluctuation of -5.3inches or -134millimeters (1961-2014). The study area was a highly humid climate in 1961, while recently it seems on the porch of sub-humid ambiance. The annual trends show depletion in the precipitation concentration since 1980. Based on temperature, there are three types of temperature zones that are cool, cold and highlands. The maximum temperature recorded in June as well as July and reversed in January. The average temperature indicates a rise of 0.20C, which is higher during winters and converse in summers. The swell in the degree of hotness enhanced the water anxiety as well as the recoil of glaciers and increased the rate of natural hazards. The hydrology of the area is highly susceptible to the alteration in weather conditions in terms of glaciers retreat; fall in river flow, sub-surface water, natural disasters, desiccation of ponds and water springs. The yearly runoff of the Swat river reveals a decrease of -0.03 m3/Sec, while it is 12.4 m3/Sec in the Ghurband river (Shangla). It is concluded, that the yearly inclination of water runoff is contrary to mean temperature and directly proportional to precipitation. The most frequent natural disasters of the study area comprise of earthquakes, floods, landslides, snow avalanches, forest fires and epidemics (hepatitis, stomachache, and cholera). These hazards can be minimized using well planning (top to bottom) for risk management, preparedness, vulnerabilities and mitigation strategies at the community level in the area.

Separating surface flow (SF) from subsurface flow (SSF) based on direct runoff measurements in river gauges is an important issue in hydrology. In this study, we developed a simple and practical method, based on runoff coefficient (RC), for separating SF from SSF. RC depends mainly on soil texture, land use and land cover, but we also considered the effect of slope and rainfall intensity. We assessed our RC-based method for three different soil types by comparing the value obtained with laboratory rainfall simulator data. The correlation coefficient between observed and calculated data exceeded 0.93 and 0.63 when estimating SF and SSF, respectively. The method was then used to separate SF and SSF in two catchments (Heng-Chi and San-Hsia) in Northern Taiwan, and the results were compared with those produced by the geomorphological instantaneous unit hydrograph (GIUH) model. Test revealed that, if RC is calculated accurately, the proposed method can satisfactorily separate SF from SSF at catchment scale. [ABSTRACT FROM AUTHOR]

Nutrient absorption is a function, among others, aimed at macrophytes for wastewater treatment. In this work, Typha angustifolia, Phragmites australis, and Sparganium erectum were multi-annually compared in secondary and tertiary treatment of urban wastewater under Mediterranean climate. Phragmites shows higher growth in height and density during the vegetative period of 1.83-2.09 cm.d-1 and 29-49 times the planting density, respectively. Aerial biomass records 52.2-54.3, 38.1-41.0, and 19.4 t dw.ha-1 in Phragmites, Typha, and Sparganium in the same order. The underground biomass fluctuates depending on the rooting vigour from 1.45 t dw.ha-1 for Sparganium to 44.49 t dw.ha-1 for Phragmites in tertiary treatment. Nitrogen and phosphorus aerial mineralomasses are more important in Phragmites (787 kg N.ha-1) and Typha (107 kg P.ha-1) in secondary treatment. Phragmites is, by far, the most cumulative of N and P in its underground part. The N and P retention by the vegetated mesocosms apparently has overall relationship with N-NH4+ and P-PO43-. Compared to mesocosm input, Phragmites assimilates one’s maximum of 6.39% N in its aerial tissues and 7.86% P in the underground ones, whereas Typha records maxima of 14.8% N and 33.6% P in its aerial part with respect to corresponding mesocosm removal. ABSTRAK:Penyerapan nutrien adalah satu fungsi, antara lain, bertujuan untuk makrofit merawat sisa air. Kajian ini menggunakanTypha angustifolia, Phragmites australis dan Sparganium erectumbagi membandingkan pelbagai-jenis rawatan sekunder dan tertiar sisa air bandar pada iklim Mediterranean. Phragmites menunjukkan pertumbuhan tertinggi dalam ketinggian dan ketumpatandalam tempoh vegetatif iaitu 1.83-2.09 cm.d-1dan 29-49 kaliketumpatan penanaman, masing-masing. Rekod biojisim udara mencatatkan 52.2-54.3, 38.1-41.0, dan 19.4 t dw.ha-1 dalam Phragmites,Typha, dan Sparganium pada susunan sama. Biojisim bawah tanah berubah-ubah bergantung kepada kekuatanakar dari 1.45 t dw.ha-1 untuk Sparganium hingga 44.49 t dw.ha-1 untuk Phragmites dalam rawatan tertiar. Nitrogen dan Fosforus Mineralomassa udara adalah lebih penting untukPhragmites (787 kg N.ha-1) dan Typha (107 kg P.ha-1) dalam rawatan sekunder. Phragmites, setakat ini, paling kumulatif bagi N dan P pada bahagian bawah tanah. Pembendungan N dan P oleh mesokisme tumbuh-tumbuhan secara nyata berkaitan dengan N-NH4+ dan P-PO43-. Berbanding input mesokisme,Phragmites mengasimilasi maksimum pada N 6.39% tisu udara dan P 7.86% bahagian bawah tanah, manakala Typha mencatatkan maksima N 14.8% dan P 33.6% pada bahagian udara dengan penyingkiran mesokisme sepadan. ABSTRAK: Penyerapan nutrien adalah satu fungsi, antara lain, bertujuan untuk makrofit merawat sisa air. Kajian ini menggunakan Typha angustifolia, Phragmites australis dan Sparganium erectum bagi membandingkan pelbagai-jenis rawatan sekunder dan tertiar sisa air bandar pada iklim Mediterranean. Phragmites menunjukkan pertumbuhan tertinggi dalam ketinggian dan ketumpatan dalam tempoh vegetatif iaitu 1.83-2.09 cm.d-1 dan 29-49 kali ketumpatan penanaman, masing-masing. Rekod biojisim udara mencatatkan 52.2-54.3, 38.1-41.0, dan 19.4 t dw.ha-1 dalam Phragmites, Typha, dan Sparganium pada susunan sama. Biojisim bawah tanah berubah-ubah bergantung kepada kekuatan akar dari 1.45 t dw.ha-1 untuk Sparganium hingga 44.49 t dw.ha-1 untuk Phragmites dalam rawatan tertiar. Nitrogen dan Fosforus Mineralomassa udara adalah lebih penting untuk Phragmites (787 kg N.ha-1) dan Typha (107 kg P.ha-1) dalam rawatan sekunder. Phragmites, setakat ini, paling kumulatif bagi N dan P pada bahagian bawah tanah. Pembendungan N dan P oleh mesokisme tumbuh-tumbuhan secara nyata berkaitan dengan N-NH4+ dan P-PO43-. Berbanding input mesokisme, Phragmites mengasimilasi maksimum pada N 6.39% tisu udara dan P 7.86% bahagian bawah tanah, manakala Typha mencatatkan maksima N 14.8% dan P 33.6% pada bahagian udara dengan penyingkiran mesokisme sepadan.

Background and Objective: Synthetic wetlands are engineering systems that use natural plants, soils and organisms to purify municipal polluted water and remove nitrate. Materials and Methods: In this study, three systems were considerd as soil culture, three systems as plant cultivation on floating plates and three other systems without plant and porous bed as. The experiments were done three times within six months. The hydraulic retention times were 1, 3 and 5 days. The experimental design consisted of a factorial split-plot design. The analysis of variance showed that the efficiency of nitrate removal was affected by the type of constructed wetland, HRT, and temperature changes (p≤0.01). Results: At the HRT of 1 day, the average efficiency of nitrate removal by the soil culture, plant cultivation on floating plates and control were 14.34%, 12.09% and 10.51%, respectively. At the HRT of 3 days, the average efficiencies were 17.62%, 15.76% and 13.54%, respectively. At the HRT of 5 days, the efficiencies were increased and they were 17.75%, 17.66% and 16.08%, respectively. Conclusion: The results showed that the soil culture were more efficinet in removing nitrate .Also, the Cyperus alternifolius plant has the potential of nitrate phytoremediation.

The study area comprises of humid and undifferentiated highland climates having total precipitation of 52inches (1320mm) and fluctuation of -5.3inches or -134millimeters (1961-2014). The study area was a highly humid climate in 1961, while recently it seems on the porch of sub-humid ambiance. The annual trends show depletion in the precipitation concentration since 1980. Based on temperature, there are three types of temperature zones that are cool, cold and highlands. The maximum temperature recorded in June as well as July and reversed in January. The average temperature indicates a rise of 0.20C, which is higher during winters and converse in summers. The swell in the degree of hotness enhanced the water anxiety as well as the recoil of glaciers and increased the rate of natural hazards. The hydrology of the area is highly susceptible to the alteration in weather conditions in terms of glaciers retreat; fallin river flow, sub-surface water, natural disasters, desiccation of ponds and water springs. The yearly runoff of the Swat river reveals a decrease of -0.03 m3/Sec, while it is 12.4 m3/Sec in the Ghurband river (Shangla). It is concluded, that the yearly inclination of water runoff is contrary to mean temperature and directly proportional to precipitation. The most frequent natural disasters of the study area comprise of earthquakes, floods, landslides, snow avalanches, forest fires and epidemics (hepatitis, stomachache, and cholera). These hazards can be minimized using well planning (top to bottom) for risk management, preparedness, vulnerabilities and mitigation strategies at the community level in the area.

Drainage modeling that accurately captures urban storm inundation serves as the foundation for flood warning and drainage scheduling. In this paper, we proposed a novel coupling ideology that, by integrating 2D-1D and 1D-2D unidirectional processes, overcomes the drawback of the conventional unidirectional coupling approach that fails to properly represent the rainfall surface catchment dynamics, and provides more coherent hydrological implications compared to the bidirectional coupling concept. This paper first referred to a laboratory experimental case from the literature, applied and analyzed the coupling scheme proposed in this paper and the bidirectional coupling scheme that has been widely studied in recent years, compared the two coupling solutions in terms of the resulting accuracy and applicability, and discussed their respective strengths and weaknesses to validate the reliability of the proposed method. The verified proposed coupling scheme was then applied to the modeling of a real drainage system in a region of Nanjing, China, and the results proved that the coupling mechanism proposed in this study is of practical application value., Competing Interests: The authors declare there is no conflict., (© 2024 The Authors This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY-NC-ND 4.0), which permits copying and redistribution for non-commercial purposes with no derivatives, provided the original work is properly cited (http://creativecommons.org/licenses/by-nc-nd/4.0/).)

The aim of this study was to investigate how to adjust groundwater withdrawal in the Zayandeh-Rud River Basin in the arid region of central Iran due to changes in groundwater balance components. Two time periods (2006–2012 and 2013–2019) were considered to evaluate changes in groundwater level and different components affecting these changes. Groundwater level unit hydrographs in 6 important aquifers (in terms of groundwater abstraction) located in this study area were prepared using the Thiessen method. Also, the changes in precipitation and evapotranspiration in the study area were determined in both time periods. Groundwater balance equation was revised based on changes in precipitation, evapotranspiration, and surface flow variations between these two time periods. Results showed that the groundwater level has a negative trend since 2013. By 2012, the annual groundwater level increased about the 0.42 m, but from 2013 to 2019, the annual groundwater level declined about the 1.2 m, approximately. The surface flow had the more adjustment coefficient and contribution with groundwater recharge. Due to the decrease in precipitation and surface flow, increase in evapotranspiration, and adjustment of groundwater overdraft, in total, the groundwater withdrawal should be reduced from 2228.9 to 1929.1 MCM (13.1% decrease) in the study area. [ABSTRACT FROM AUTHOR]

Gas-liquid two-phase flow is widely used in many engineering fields, and bubble dynamics is of vital importance in optimizing the engineering design and operating parameters of various adsorptive bubble systems. The characteristics of gas-liquid two-phase (e.g., bubble size, shape, velocity, and trajectory) remain of interest because they give insight into the dynamics of the system. Bubble plumes are a transport phenomenon caused by the buoyancy of bubbles and are capable of generating large-scale convection. The surface flow generated by bubble plumes has been proposed to collect surface-floating substances (in particular, oil layers formed during large oil spills) to protect marine systems, rivers, and lakes. Furthermore, the surface flows generated by bubble plumes are important in various types of reactors, engineering processes, and industrial processes involving a free surface. The bubble parameters play an important role in generating the surface flow and eventually improving the flow performance. This paper studies the effects of temperature on bubble parameters and bubble motion to better understand the relationship between the various bubble parameters that control bubble motion and how they impact the formation of surface flow, with the ultimate goal of improving the efficiency of the generation of surface flow (i.e., rapidly generate a strong, high, and wide surface flow over the bubble-generation system), and to control the parameters of the surface flow, such as thickness, width, and velocity. Such flow depends on the gas flow rate, bubble size (mean bubble diameter), void fraction, bubble velocity, the distance between bubble generator and free surface (i.e., water height), and water temperature. The experiments were carried out to measure bubble parameters in a water column using the image visualization technique to determine their inter-relationships and improve the characteristics of surface flow. The data were obtained by processing visualized images of bubble flow structure for the different sections of the bubble regions, and the results confirm that temperature, bubble size, and gas flow rate significantly affect the flow structure and bubble parameters. [ABSTRACT FROM AUTHOR]

Soil total carbon (TC), phosphorus (P), and nitrogen (N) exports from the weathered granite slopes are greatly influenced by the complex hydrological processes and terrain factors. In this study, the coupling loss characteristics of N-P-C via runoff and sediment were studied with two soil tanks under simulated rainfalls. Three soils respectively derived from the tillage layer (T-soil), laterite layer (L-soil), and sand layer (S-soil) were employed to determine the interactions of hydrology and topography on N-P-C exports under three rainfall intensities (1.5, 2.0, and 2.5 mm/min). The erosion degree of different soils displayed an order of S-soil > L-soil > T-soil. The results showed that surface flow was the main runoff form for L- and T-soil, while underground flow was predominant for S-soil. There was a linear correlation between sediment and surface flow (R2 > 0.78). Surface flow was the dominant pathway of P loss via runoff with underground flow being an important supplementation, and the main P loss pattern switched between dissolved phosphorus (DP) and particle phosphorus (PP) during the experiment. However, P lost via eroded sediment accounted for more than 94% of the TP loss amount. N presented an opposite trend to P and was mainly lost via underground flow. The main N loss form in surface and underground flow was NO3−-N. Underground flow was the predominant total nitrogen (TN) loss pathway for S- and L-soil, followed by sediment and surface flow. For T-soil, TN lost via runoff was much greater than that carried by eroded sediment. TC for S-soil was mainly lost via underground flow while that for L- and T-soil was mostly lost via surface flow. Both N-P loss loads in surface flow and P loss load in underground flow were positively correlated with TC loss load (p < 0.05), indicating that the presence of organic matter brings about more nutrient losses. These results expand our understanding of the combined effects of rainfall intensity and erosion degree on runoff and sediment yields as well as N-P-C losses from the bare weathered granite slopes of SE China. [ABSTRACT FROM AUTHOR]

• Critical rainfall for recharging flat sandy lands is 15 mm in hyper-arid desert. • Lateral gravity water flow and surface flow on sandy slopes were identified. • Water flow on sandy slope improves the recharge rate of deep soil from rainfall. • Local rainfall has the capacity to sustain the development of Badain Jaran Lake. • Extreme rainfall does not play a decisive role in the sustaining of desert lake. To elucidate the slope hydrology and their influence on the regional water balance and desert lake development, water migration and soil water conditions were studied in the megadunes of Badain Jaran Desert. Simulated rainfall of 15–60 mm with infiltration depths of ∼ 0.3–0.5 m, the lateral water migration ratios of ∼ 52.9 %-86.2 % and the differential distribution of tracers with depth in the flat sand lands indicate that 15 mm rainfall is the critical rainfall for effective recharge of deep soil water and that there is a shift from piston flow to preferential flow of water during infiltration. Soil micro-bedding and 4.2 % soil gravity water from locally wet surface soils and 6 mm of natural rainfall resulted in lateral migration of the tracer ∼ 1.2 m and 0.4 m in the slope surface and soil respectively, indicate surface flow and lateral gravity water flow resulting from differences in hydraulic conductivity and water-holding capacity of the soil micro-bedding. Soil water storage at 0–4 m depth showed that the bottom of the slope was ∼ 30 mm higher than the middle of the slope after the rainy season and ∼ 9 mm higher before the rainy season; in general the post-rainy season was ∼ 30–40 mm higher than the pre-rainy season. Surface flow and lateral gravity water flow in unsaturated soils increase the intensity of lateral water movement on the slope and improve the effective conversion rate of rainfall to deep soil water, especially below 15 mm. Annual recharge of deep soil water, assessed using soil water change and critical rainfall, will not be less than 8.5 mm and may even reach an upper limit of ∼ 30–40 mm. The megadune slopes respond strongly to local precipitation, which is sufficient to maintain the lake, but extreme precipitation does not play a decisive role. The methods and results provided in this work can advance our understanding of the desert hydrological cycle and water resources. [ABSTRACT FROM AUTHOR]

In gravity irrigation, how water is distributed in the soil profile makes it necessary to study and develop methodologies to model the process of water infiltration and redistribution. In this work, a model is shown to simulate the advancing front in border irrigation based on the one dimensional equations of Barré de Saint-Venant for the surface flow and the equation of Green and Ampt for the flow in a porous medium. The solutions were obtained numerically using a finite difference Lagrangian scheme for the surface flow and the Raphson method for the subsurface flow. The model was validated with data obtained from the literature from an irrigation test and its predictive capacity was compared with another model and showed excellent results. The hydrodynamic parameters of the soil, necessary to obtain the optimal irrigation discharge, were obtained through the solution of the inverse problem using the Levenberg–Marquardt optimization algorithm. Finally, the results found here allow us to recommend that this model be used to design and model border irrigation, since the infiltration equation uses characteristic parameters of the physical soil.

This paper investigates the application of the transient storage (TS) model for free surface flow-through rockfill media by some modification in the principles of it. For this purpose, firstly, a new analytical solution is derived by using the concepts of the VART model. In the following, a series of experiments have been operated in a box flume with two inflow rates and five injection masses. EC probes have been employed to catch breakthrough curves. Furthermore, analytical temporal moment's equations have been derived for the numerical calculation of the TS model parameters. Also, they have been calculated for the new proposed model using the least square curve fitting method. Finally, the findings showed that the TS model, with its new analytical solution, is entirely applicable to rockfill media. Finally, the statistical analyses indicated that the model performance is excellent. [ABSTRACT FROM AUTHOR]

Assessing the performance and capability of drainage pipes is of significance for computing urban flooding. However, drainage-pipe data is not available for most urban areas, therefore raising the problem for computing the drainage capability in an approximate way. To resolve this problem, a new type of approach that improves on the existing approach, termed the inlet-drainage approach, is proposed by assuming the drainage effects as a mass subtracted in particular parts, e.g., the area with gullies or inlets. The proposed approach is incorporated into a 2D hydrodynamic model for surface flow to simulate the coupled rainfall-runoff-drainage-inundation processes. Through validation against the measured and modeled results in two test cases involving ideal and realistic urban catchments, it is demonstrated that the proposed new approach could provide fairly good modeled results for computing drainage effects. More importantly, the new approach is simple and easy to implement.

Because nutrients including nitrogen and phosphorus are generally limited in tropical forest ecosystems in Puerto Rico, a quantitative understanding of the nutrient budget at a watershed scale is required to assess vegetation growth and predict forest carbon dynamics. Hurricanes are the most frequent disturbance in Puerto Rico and play an important role in regulating lateral nitrogen and phosphorus exports from the forested watershed. In this study, we selected seven watersheds in Puerto Rico to examine the immediate and lagged effects of hurricanes on nitrogen and phosphorous exports. Our results suggest that immediate surges of heavy precipitation associated with hurricanes accelerate nitrogen and phosphorus exports as much as 297 ± 113 and 306 ± 70 times than the long-term average, respectively. In addition, we estimated that it requires approximately one year for post-hurricane riverine nitrogen and phosphorus concentrations to recover to pre-hurricane levels. During the recovery period, the riverine nitrogen and phosphorus concentrations are 30 ± 6% and 28 ± 5% higher than the pre-hurricane concentrations on average.

Long-term experimental data collected by the authors were analyzed to characterize the formation of spring surface flow in different natural zones of the Volga and Don basins with the use of water-balance method (hydrologic experimental plots) for its treatment, and literary data on such studies were generalized. The obtained unique material was used to characterize the surface runoff separately from loose and compacted plowed lands and to evaluate the runoff-regulating role of the fall tillage of soil. The analysis of theoretical curves of runoff exceedance probability showed that its mean values and the different exceedance probability decrease from N toward S and SE, and the difference between the loose and compacted plowed lands increases. However, in some years, runoff inversion can be seen, i.e., its volume in the forest-steppe zone is less than in the steppe zone, where it can be high. This suggests that the effect on runoff formation produced by anthropogenic factors is less than that of natural factors, forming under different climate conditions, varying over zones and years. [ABSTRACT FROM AUTHOR]