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Within major city confines, floods are a major cause of worry and are mainly due to excessive urbanization encroaching on natural landscapes which would otherwise have served as areas of infiltration. The study combines the growth of urban landscape to estimate the maximum surface runoff and aimed to quantify this runoff generated and peak discharge for better urban management practices. These past five decades, the area experienced erratic expansion along with various changes in its land classification, resulting in several flood events in various parts. Runoff estimation was made using Curve Number method for the watershed. Annual rainfall deviation from mean saw an increase by 16% on an average in the past decade, with more than a 100% deviation from mean in 2017. Topographical maps generated to study the changes contributing to flood situations show a 90% increase in concretization over the past two decades and more than 50% reduction in the amount of natural vegetative cover in that same time period. Statistical analysis shows a good fit of the selected model for runoff estimation and well correlated variables. The model satisfactorily predicted runoff from the simulated data analysis with evaluation criteria NSE = 0.9945, MAE = 5.4121, r = 0.9975, R2 = 0.9949, RMSE = 6.8117 and PBias = 1.1436. The results revealed a steady increase in yearly runoff, due to topographical changes and increase in precipitation intensity over time. The study suggests intervention efforts be targeted spatially to ensure suitable flood-control structures and systems. [ABSTRACT FROM AUTHOR]

Drainage systems in urban areas are designed to collect and transport stormwater from citizen areas. However, the water in drainage systems might contain untreated, misconnected, or low-treated sewage and polluted runoff and potentially pollute neighboring urban rivers. In this study, the drainage waters in Taipei city, Taiwan, were investigated, and the impacts on water quality in the receiving Keelung River were assessed by the Water Quality Analysis Simulation Program (WASP) and five scenarios. If the drainage outlets were not intercepted but discharged to the river, the BOD and NH3-N in the Keelung River would increase by 5.7% and 2.9%, respectively. Moreover, the BOD concentration under low-flow conditions (Q75) increased by 30%, and the NH3-N increased by 37.6%. If all domestic wastewater is treated and zero point pollution sources in the drainage water in the future, the BOD could decrease by 55.4%, and the NH3-N could decrease by 44.8%. [ABSTRACT FROM AUTHOR]

The dynamics of fluvial erosion responds to soil erosion and surface runoff on hillslopes due to land use and environmental fragility, conditioned by the soil, geology, relief, and rainfall rate. Despite the increasing problems associated with fluvial erosion in Brazil, little information is available on bedload transport in headwater catchments under intense agricultural activity. Therefore, this study sought to characterize the fluvial erosion processes and bedload dynamics in an experimental catchment in southern Brazil located at the edge of the Brazilian Meridional plateau, which is representative of a large area of high environmental fragility and intense agricultural activity in Southern Brazil. The Guarda Mor River drains a headwater catchment (18.5 km2) with undulating and hilly terrain with fragile soils and intense agricultural activity controlling fine and coarse sediment supply downstream. During 11 major rainfall-runoff events, monitoring was conducted to measure streamflow, bedload transport rates, sediment size, and hydraulic parameters, such as Manning's n values and viscous layer thicknesses. A rating curve was established based on 40 streamflow and bedload discharge measurements taken at different water levels and stages along the hydrograph. In addition, a river portion (gravel bed) was characterized as well as the granulometric characteristics of its surface and subsurface layers. The results showed that the transport pattern is influenced by factors other than hydraulic parameters alone, including the interdependence between successive events, armoring effects, and hysteresis. These factors are strongly related to the surface runoff and erosion observed on the hillslopes, which define the streamflow energy and the supply of sand fraction, respectively. A discussion is held on the bedload transport dynamics under non-equilibrium conditions in the modeling of fluvial erosion processes. [ABSTRACT FROM AUTHOR]

PAM (polyacrylamide) had been used to control and prevent soil erosion. In order to explore the best way to apply PAM and pro- mote the application of PAM in soil erosion control practice, conical loessal soil engineering accumulation was set up in the gullied rolling loess area, with no application PAM as the control, according to the application amount of 2.0 g/m², PAM was applied on the surface of loessal soil engineering accumulation by spraying water first and then dry scattering PAM, dry scattering PAM first and then spraying water, and directly spraying PAM solution from May to October 2022, the surface runoff, erosion sediments, rill development, soil moisture and soil bulk density of loessal soil engineering accumulation with different PAM application methods were monitored under natural rainfall conditions. The results show that the application of PAM in three ways can increase the runoff frequency, surface runoff and runoff coefficient, and can reduce the amount of sediment yield, the number of rill development, the amount of rill erosion, the erosion coefficient of rill and the soil water content. Their effects are ranked as directly spraying PAM solution > dry scattering PAM first and then spraying water > spraying water first and then dry scattering PAM. The effect of dry scattering PAM first and then spraying water spraying is equivalent to that of directly spraying PAM solution. Considering the convenience of operation and ensuring the effect, PAM application mode is recommended to be dry scattering PAM first and then spraying water, or according to the weather forecast, directly dry scattering PAM before rainfall. [ABSTRACT FROM AUTHOR]

This study introduces two novel DEM-based distributed rainfall-runoff models derived from the existing Hidropixel model: HidropixelTUH+ and HidropixelDLR. These models account for spatial variations in direct runoff generation, translation, and storage within a watershed, considering spatial variability in rainfall and basin characteristics. In HidropixelTUH+, a Triangular Unit Hydrograph (TUH) is determined for each Digital Elevation Model (DEM) pixel and lagged to the watershed outlet based on the travel time from the pixel to the outlet. In HidropixelDLR, a hydrograph is estimated for each pixel based on the travel time, which takes translation effects into account. To represent the storage effects, this hydrograph is attenuated by a linear reservoir at each pixel. Both approaches were applied to the Upper Medway catchment (250 km2) in southeastern England, using rainfall data from a rain gauge network. The outcomes revealed that the proposed approaches provided a reasonably accurate prediction of the hydrographs and exhibited notably superior performance compared to the original version of Hidropixel, which has limited capabilities in capturing translation effects. HidropixelTUH+ and HidropixelDLR predicted peak flows with an average absolute error of 11% and 10%, respectively. The HidropixelDLR achieved a more accurate time-to-peak estimation, with an average absolute error of 1 h, compared to the 1.5-h error from HidropixelTUH+. Additionally, the HidropixelDLR predicted the full direct runoff hydrograph more accurately, achieving an average Nash–Sutcliffe coefficient (NSE) of 0.89, while the HidropixelTUH+ had an NSE of approximately 0.84. [ABSTRACT FROM AUTHOR]

This study investigates the impacts of Land Use/Land Cover (LULC) changes and climate change on surface runoff in Gdańsk, Poland, which is crucial for local LULC planning and urban flood risk management. The analysis employs two primary methodologies: remote sensing and hydrological modeling. Remote sensing was conducted using Google Earth Engine and Land Change Modeler in IDRISI Terrset software to analyze historical (1985–2022) and future (2050–2100) LULC. Hydrological modeling was performed using the Natural Resources Conservation Service curve number method to assess the overall impact of LULC changes on Gdańsk's hydrology at the local scale. The Orunia basin, a critical area due to intensive LULC development, was selected for detailed hydrological analysis using the Hydrologic Modeling System (HEC-HMS). The analysis encompassed three scenarios: LULC changes, climate change, and combined LULC and climate change effects. The LULC analysis revealed a marked increase in urban area, a shift in forest and vegetation cover, and a reduction in agricultural land. HEC-HMS simulations showed an increase in the runoff coefficient across selected decades, which was attributed to the combined effect of LULC and climate change. The projected increases under the Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 scenarios for 2050 and 2100 are projected to surpass those observed during the baseline period. The findings highlight that the synergistic effects of LULC and climate change have a more significant impact on Gdańsk's hydrology at both local and basin scales than their separate effects. These insights into LULC shifts and urban hydrological responses hold implications for sustainable urban planning and effective flood risk management in Gdańsk and similar urban settings. [ABSTRACT FROM AUTHOR]

The upstream area of the watershed has high rainfall, resulting in large volumes of runoff and peak discharge. The runoff discharge causes soil erosion, transporting soil particles by the flow and eventually settling as sedimentation. This sedimentation leads to river siltation and narrowing. Additionally, high-flow discharge causes turbulence and flooding. This research aimed to predict sedimentation rates due to land erosion in the watershed using the GIS-based Modified Universal Soil Loss Equation (MUSLE). The study was conducted in the Krueng Peuto sub-watershed in Indonesia. The interphase modeling revealed that the highest land sedimentation rate in the Krueng Peuto watershed occurred in 2015, with the sediment of 40,503.10 Mg.y−1, while the least was in 2013, with 2,006.52 Mg.y−1 of sediment. The results indicate that surface runoff has the most significant influence on land sedimentation. The rate of soil loss is closely related to land conservation practices, with poorly vegetated land contributing the most to surface runoff. Water flow velocity and its destructive power erode the soil into tiny grains, transported and deposited as sedimentation in the river. The MUSLE's capability in identifying erosion-prone areas and predicting sediment yield based on rainfall events is crucial for effective sediment management planning. Implementing long-term land conservation measures is essential to preserve land capacity effectively. [ABSTRACT FROM AUTHOR]

Several techniques, such as hydromulching (HM) and addition of organic residues (such as biodegradable plastics, BP) to soil have been proposed for conservation of soil affected by deforestation and wildfire. However, there is the need to support the task of land managers for the adoption of the most effective soil conservation technique, considering that the impacts on soil properties and hydrology are different due to the different mechanisms (mainly based on root actions for hydromulching and on supply of organic matter for application of bioplastics residues). This study comparatively evaluates the hydrological and erosive effects of HM, addition of BP residues to soil, and lack of any treatments (control) at the plot scale and under simulated rainfall in deforested and burned forestlands of Northern Iran. These effects have been associated to changes in key properties of soil and root characteristics due to the treatments, using multivariate statistical analysis. Moreover, regression models have been setup to predict surface runoff and soil erosion for both treatments. HM was more effective (–65% of runoff and –61% in soil loss) than application of BP (–22% and –19%, respectively) in controlling the soil's hydrological and erosive response, the latter being extremely high in control plots (over 6 tons/ha). These reductions were closely associated to significant increases in organic matter and aggregate stability of soil, to a decrease in bulk density after the treatments, and to the grass root growth, which further improved soil hydrology after HM. The Principal Component Analysis provided a synthetic parameter measuring the soil response to rainfall and treatments. The cluster analysis discriminated the three soil conditions (HM, application of BP and control), according to the changes in soil properties and root growth in HM, in as many groups of soil samples. The multiple regression analysis provided two linear models that predict surface runoff and soil loss with a very high accuracy (r2 > 0.98) for a precipitation with given depth and intensity. [ABSTRACT FROM AUTHOR]

In a result of the increase in impervious surfaces in the urbanized area, there is an increase in surface runoff and at the same time an overload of the sewage network. In order to reduce the mentioned negative impacts in the inner city of Bratislava, this study was developed. The aim of this study was to design as possible the most efficient possible infiltration device for capturing rainwater and keeping it at the point of impact of precipitation of the addressed site. The Novohradska Grammar School campus was chosen as the area of interest. It is assumed that, together with elements of green infrastructure, these measures will be able to contribute in order to mitigate the adverse effects of urbanization in the capital. [ABSTRACT FROM AUTHOR]

The Qinling Mountains, the so-called "central water tower," are extremely important water resource hubs in China. The influence of the forest ecological environment on water quality is complicated. Therefore, to investigate the spatiotemporal variations in water quality, we employed a random forest model to integrate multiple key water quality indicators into one overall ranking value. Monthly monitoring data of surface runoff and atmospheric precipitation events (2003–2022) for the Huodigou stream in the Qinling Mountains were used. The results revealed that after atmospheric precipitation entered the forest ecosystem, the coefficients of variation of surface runoff for most of the selected indicators decreased, but there were significant differences among the six indicators (NO3−, Mg2+, Na+, pH, K+, Ca2+). Most of the indicators within surface runoff were positively correlated, such as those in atmospheric precipitation. However, some indices of surface runoff were negatively correlated with those of atmospheric precipitation, and there was a significant negative correlation between Ca2+ in atmospheric precipitation and Ca2+ in surface runoff and between NO3−in atmospheric precipitation and K+ and Na+ in surface runoff (p < 0.01). The water quality grade of the surface runoff generated by atmospheric precipitation through forest ecosystems was significantly improved (p < 0.001), among which the average water quality grade of surface runoff was approximately 3.6, that is, between Grade I-3 and Grade I-4, whereas the average water quality grade of atmospheric precipitation was approximately 4.5, that is, between Grade I-4 and Grade I-5. The order of improved water quality was NO3− > Mg2+ > Na+ > pH > K+ > Ca2+. Overall, our assessment revealed that from 2003 to 2022, the water quality grade in the Huodigou stream improved and was more stable. In summary, the forest ecosystem in the Huodigou stream has a significant water quality purification effect on the atmospheric precipitation it receives. Our novel criterion-based approach for categorizing the water quality of atmospheric precipitation and surface runoff offers a new tool for examining spatiotemporal stream water quality variations in the Qinling region and other mountainous areas. [ABSTRACT FROM AUTHOR]

As the climate crisis progresses, droughts and the seasonal availability of fresh water are becoming increasingly common in different regions of the world. One solution to tackle this problem is the reuse of treated wastewater in agriculture. This study was carried out in two significant hydrographic regions located in the southeast of Brazil (Mogi Guaçu River Water Management Unit—UGRHI-09 and Piracicaba River Basin—PRB) that have notable differences in terms of land use and land cover. The aim of this study was to carry out a multi-criteria analysis of a set of environmental attributes in order to classify the areas under study according to their levels of soil suitability and runoff potential. The integrated analysis made it possible to geospatialize prospective regions for reuse, under two specified conditions. In the UGRHI-09, condition 1 corresponds to 3373.24 km2, while condition 2 comprises 286.07 km2, located mainly in the north-western and central-eastern portions of the unit. In the PRB, condition 1 was also more expressive in occupational terms, corresponding to 1447.83 km2; and condition 2 was perceptible in 53.11 km2, predominantly in the central region of the basin. The physical characteristics of the areas studied were decisive in delimiting the areas suitable for the reuse of treated wastewater. [ABSTRACT FROM AUTHOR]

Water is a critical natural resource, comprising approximately 60% of human body weight and playing a vital role in all physiological processes. However, water quality has deteriorated in recent years due to the presence of harmful contaminants, posing potential health risks. Hence, the objective of this paper is to assess the modelling runoff and sediment yield dynamics of the Upstream of Eleyele Lake Watershed, Oyo State, Nigeria using Geographic Information Systems (GIS) alongside the Soil and Water Assessment Tool (SWAT). The model's predictions indicated an annual surface runoff of 122.56 m³/s and a sediment yield of 26.02 t/ha within the study area. These levels suggest a significant risk of flooding and heightened susceptibility to soil erosion. Consequently, it is recommended that further modeling efforts be employed to identify erosion-prone zones with greater precision across the watershed, enabling the development of effective management strategies to mitigate these risks. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the spatiotemporal variation in water quality in the Grande River and the Ondas River, in the city of Barreiras, Bahia, Brazil. Water samples were collected at 11 points along the rivers, and eight physical–chemical parameters (electrical conductivity, pH, alkalinity, apparent and true color, turbidity, dissolved oxygen, and biochemical oxygen demand) and three microbiological indicators (heterotrophic bacteria, total and thermotolerant coliforms) were analyzed. Spatiotemporal variation was assessed using the multivariate techniques of principal component analysis/factorial analysis (PCA/FA) and hierarchical cluster analysis (HCA). The results of the PCA/FA highlighted eight of the eleven parameters as the main ones responsible for the variations in water quality, with the greatest increase in these parameters being observed in the rainy season, especially among the points influenced by sewage discharges and by the influence of the urban area. The CA grouped the results from 11 points into three main groups: group 1 corresponded to points influenced by sewage discharges; group 2 grouped points with mainly urban influences; and group 3 grouped points in rural areas. These groupings showed the negative influence of urbanization and also statistically significant variations between the groups and periods. The most degraded conditions were in group 1, and the least degraded conditions were in group 3. Assessment of the variations between the monitoring periods showed that rainfall had a significant impact on the increase or decrease in the parameters assessed, as a result of surface runoff linked to urbanization and increased river flow. [ABSTRACT FROM AUTHOR]

Hydrosedimentalogical models contribute to management of water resources, provided they are based on robust monitoring and calibration–validation strategies. The Limburg Soil Erosion Model (LISEM) properly represents runoff and sediment yield from watersheds with deep, clayey, weathered soils intensely occupied with grain production and dairy farming. Runoff and sediment yield in this agricultural environment have significant economic and off-site ecological importance, as the watersheds are connected to a large reservoir responsible for energy production and water supply. The objective of the study was to test whether LISEM is efficient in runoff and sediment yield modeling (calibration and validation) in paired watersheds with clayey weathered soils, under dairy cattle grazing and no-tillage grain production. The LISEM adequately represented runoff and erosion processes in the calibration phase (2018–2019), with Nash and Sutcliffe efficiency coefficient up to 0.94 and 0.92 for surface runoff, and 0.89 and 0.88 for sediment yield, respectively, for NW and SW watersheds. Some model parameters required significant adjustments, e.g., Ksat at 78.5% and 49.1%, initial soil moisture at 5.5% and 2.5%, soil cohesion at 24.1% and 4.6%, and aggregate stability at 21.4% and 4.6%, respectively for NW and SW watersheds. During the validation period (2020–2021), the model exhibited constraints in adequately representing the hydrosedimentological processes, with only a few rainfall events showing accurate results. Thus, for the utilization of a validated LISEM in future climate scenarios, the model still requires thorough scrutiny of the equations governing hydrology and erosion processes, along with continued monitoring and further model parameterization. [ABSTRACT FROM AUTHOR]

Flash flooding is one of the most noteworthy natural disasters in arid regions, especially in urban areas. The Helwan-Atfih area is a heavily populated region and part of the Eastern Desert drylands of Egypt. It is characterized by ten drainage basins that dissect it and drain toward the Nile River (Wadies of Degla, Hof, Al-Gebbu, Garawy, Hera, Al-Hay, Al-Werg, Al-Nowya, Al-Reshrash, and AL-Atfehe). Landsat-8, STRM-DEM, and CFSR remote sensing satellite data of 15 m, 30 m, and 0.3-degree resolution, respectively, were prepared and utilized to evaluate flooding hazards within the study area using the GIS-weighted overlay technique. Weighted overlay analysis is a GIS-based multi-criteria decision-making technique. This technique was performed to delineate the most vulnerable areas for flooding, depending on 14 thematic layers representing the multi-class factors that influence flood hazard (nine morphometric parameters, slope, relief, lineament density, surface lithology, and surface runoff). According to the morphometric parameters, the basins of the study area are characterized by moderate drainage densities, and moderately permeable subsoil. Limestone occupies 83.41% of the total lithological units within the basins' area, which indicates a high flooding potential. Steep slopes are primarily observed in the southern basins, especially in the Al-Reshrash basin. Wadi Al-Atfehe and Wadi Al-Reshrash have the lowest lineament density areas, reflecting a higher flooding hazard. The total runoff volume ranges between 2.42 × 106 and 12.08 × 106 m3. Based on the results, Wadi Al-Reshrash receives the highest runoff volume (12.08 × 106 m3) and has the highest slope degree (57○-71○). 85.4% of its area is covered with limestone and it has a low to moderate lineament concentration. Accordingly, Wadi Al-Reshrash is the most prone basin to flooding within the study area, followed by Wadi Al-Werg, while the other basins show a moderate flood hazard degree. [ABSTRACT FROM AUTHOR]

Abstract Within major city confines, floods are a major cause of worry and are mainly due to excessive urbanization encroaching on natural landscapes which would otherwise have served as areas of infiltration. The study combines the growth of urban landscape to estimate the maximum surface runoff and aimed to quantify this runoff generated and peak discharge for better urban management practices. These past five decades, the area experienced erratic expansion along with various changes in its land classification, resulting in several flood events in various parts. Runoff estimation was made using Curve Number method for the watershed. Annual rainfall deviation from mean saw an increase by 16% on an average in the past decade, with more than a 100% deviation from mean in 2017. Topographical maps generated to study the changes contributing to flood situations show a 90% increase in concretization over the past two decades and more than 50% reduction in the amount of natural vegetative cover in that same time period. Statistical analysis shows a good fit of the selected model for runoff estimation and well correlated variables. The model satisfactorily predicted runoff from the simulated data analysis with evaluation criteria NSE = 0.9945, MAE = 5.4121, r = 0.9975, R2 = 0.9949, RMSE = 6.8117 and PBias = 1.1436. The results revealed a steady increase in yearly runoff, due to topographical changes and increase in precipitation intensity over time. The study suggests intervention efforts be targeted spatially to ensure suitable flood-control structures and systems.

The study presents the individual technology developed by the authors for the collection and disposal of surface runoff from the facilities of the port complex for the transshipment of wood chips in the conditions of the existing port infrastructure. An analysis of the project implementation was carried out. An innovative coagulating composition has been developed that reduces the desalination of sea water, and design solutions have been developed to intensify the operation of treatment facilities. The technological solutions proposed by the authors can be applied in the design of storm sewerage for berth structures and wastewater treatment.

Purpose: to conduct a statistical analysis of the relationship between a number of natural factors and snow evaporation, melt water surface runoff during the snowmelt period on a slope with ordinary chernozem in Rostov region for various agricultural backgrounds (winter wheat and fallow) for the period 2008–2022. Materials and methods. Methodological recommendations for accounting for surface runoff were used. Statistical data analysis was performed using the MathCAD and Statistica packages. The significance of regression equations was determined using the Fisher criterion. Results. The use of statistical analysis to process the results of multifactorial studies made it possible to identify the influence of individual natural and anthropogenic factors on erosion processes and their interaction. It has been determined that the value of surface runoff on winter wheat crops depends most of all on the amount of precipitation (correlation coefficient r = 0.72...0.80), more with moldboard tillage, and on stubble plowing – on water reserves in snow (r = 0.40...0.45), also more with moldboard tillage. Conclusions. The equations of the relationship between factorial and resultant indicators of various types are presented, allowing to increase the accuracy of forecasting the surface melt water runoff value in crop rotations depending on the influencing factors with different methods of primary soil tillage, within the limits of the obtained experimental data use, which makes it possible to use methods for regulating negative erosion processes timely. The obtained regularities, reflecting the influence of soil cultivation methods and agricultural background on the value of water balance elements during snowmelt, can be used to predict the melt water surface runoff value and application of anti-erosion agrotechnical measures.

Purpose: to study the ability of the ditch-bank hydraulic structure in combination with reclamation protective forest plantings to accumulate silt sediments, carried by the surface melt and rainwater runoff, on the chernozems of Rostov region. Materials and methods. The object of research is the ditch-bank hydraulic structure in combination with a reclamation protective forest plantation near Stepnoy village, Aksay district, Rostov region, founded in 1982 under the leadership of Professor E. V. Poluektov. The experimental design consisted of three options: 1) measuring runoff at a stationary runoff site (control); 2) a ditch-bank in a reclamation protective forest plantation, surface slope 2–3°; 3) a ditch-bank in a reclamation protective forest plantation, surface slope 5–6°. The generally accepted research methods of G. V. Dobrovolsky and the methodology of the Russian Scientific Research Institute of Land Improvement Problems were used. Results. The studies were conducted in 1982–2023 for three periods: 1982–1995, 1996–2004 and 2004–2023. Archival observations of Professor E. V. Poluektov for the 1st and 2nd periods and data from studies conducted in 2023 were used. It has been determined that the simplest ditch-bank protective hydraulic structure, in the inter-row spacing of reclamation protective forest plantations, is capable of reducing soil erosion and accumulating sediment in the ditch and in front of the bank in a volume of 0.84 t/linear m with a slope of 2–3° and up to 1.74 t/linear m with a slope of 5–6°. Conclusions. It has been determined that if in the option with a slope of 2–3° there is still a overcapacity for the sediment accumulation in front of the bank, sufficient for another 40–50 years at such filling rates, then with a slope of 5–6° the ditch capacity reserves and space in front of the bank for the period 1982–2023 are filled to 96 %, therefore it is necessary to provide measures to increase the capacity for sediment accumulation.

The development of blue-green infrastructure is a new, but dynamic trend in urban ecology and city planning, especially relevant in the global climate change context, that in addition to increasing temperatures leads to intensification of storm precipitation unusual for the middle zone. The situation with surface flooding is significantly worsened not only by the high percentage of impermeable surfaces in the city, but also by small slopes, which lead to the difficulties of surface runoff. This factor is typical for old city districts or former industrial areas. The increasing storm rainfall leads to additional load on engineering communications and forces to think about alternative solutions, such as rain gardens. The paper evaluated the efficiency of flood risk reduction due to the application of rain gardens on the territory of the projected residential complex in the Moscow megalopolis. The results of modeling the surface slopes of the territory showed that ⅓ of the territory excluding highways has an unfavorable slope (less than 0.5%) for the formation of surface runoff in green areas. At the same time, the most unfavorable areas with slope below 0.003 (0.3 %) account for 13.7% of the territory. It was also determined that the predominant type of catchment surfaces of the territory are catchments of depressional landforms, the most suitable solution for surface runoff drainage for which are rain gardens. At the same time, an increase in the area of rain gardens from 1.5 to 5% of the catchment area of various functional zones showed a decrease in the calculated surface runoff rates from 0 to 78%. The greatest reduction was observed when increasing the area of rain gardens up to 3%, and further increase gave insignificant effect. At the same time, for recreational areas, replacing lawn to rain gardens by more than 2% is excessive, so when the proportion of rain gardens in parks in the study area is increased, the value of overflow tends to zero. Thus, the most effective area of rain gardens for the case study (area - 95 ha) is 2.5 ha, while in recreational zones it is recommended to use only 0.5 ha for rain gardens.

The evaluation of hydrological factors in hydrographic basins is essential for the sustainable management of water resources and the detailed planning of productive activities in a given area. The present study was developed in the Chambas River Hydrographic Basin with the objective of evaluating different hydrological factors of the basin and their contribution to the generation of hydropower and the supply of water to the agricultural sector. The methodology used consisted of constructing the flow probability curve, estimating the ecological and equipment flow; as well as evaluate the hydroenergy potential and agricultural use of the water stored in the reservoir. The results demonstrated that the daily river flows adequately adjusted the probability of occurrence using a second-order polynomial model. The turbine flow rate of the Francis turbine is 2,08 m³ s-1 and has an absolute frequency of occurrence of 170 times. The ecological flow of the river determined by the wetted perimeter method was 0.038 m³ s-1. The turbine power with the turbined flow rate of 11.30 m³ s-1 offers higher values in relation to the flow rate of 2.08 m³ s-1; However, this last result responds to the hydrological study carried out in the basin. 39% of the water stored in the reservoir is used for food production. [ABSTRACT FROM AUTHOR]

Previous studies have proven the efficiency of LID practices in mitigating surface runoff in urban watersheds; however, the impact of their placement strategy over the urban drainage system, under continuous temporal hydrological simulation, has not been explored yet. This study simulated, under continuous time scale, five LID practices and four LID placement strategies (downstream, center, upstream and uniformly) on the drainage system of the Universidade Federal de Lavras urban area, in the state of Minas Gerais, Brazil. Under the conditions analyzed, it was found that there were no significant statistical differences between the efficiency of the different LID practices, individually or combined, within the same placement strategy. The uniform placement strategy proved to be more efficient, but in soils with higher Ksat values, other strategies showed better results. Therefore, it was found that soil Ksat is a parameter that should be carefully analyzed for LID practices implementation. [ABSTRACT FROM AUTHOR]

Water resources in arid and semi-arid regions are constrained by several critical problems, including scarcity of water resources and extensive use of groundwater. Climate change and population growth will certainly result in a decline in water tables and degradation of groundwater quality. The purpose of this study is to create rainwater retention ponds in the Najran Valley located at the southern border of Saudi Arabia. Over the past decade, various researchers have reported a sharp decrease in the availability of water in the area. In addition to urban sprawl, excessive groundwater extraction is the primary cause of the decrease. Even though the valley receives a sufficient amount of rainfall throughout the year, there is no adequate rainwater management system in place. As a result of this combined water management issue, the authorities are seeking additional water storage options in addition to the Najran dam reservoir. To evaluate the flood characteristics of the region, an extensive GIS-based hydrological study is conducted. To estimate flood volumes, the critical flood-prone areas are identified and their catchments are calculated. To store rainwater generated by these catchments during rainfall events, a variety of suitable locations have been proposed for retention ponds. The construction of retention ponds would have numerous environmental benefits in addition to solving the problem of water scarcity. As a result of the study, the authorities will be able to implement a management strategy that maximizes the use of the region's water resources. [ABSTRACT FROM AUTHOR]

This study brings a systematic review that evaluated 43 articles on Nature-Based Solutions (NBS) applied to stormwater management in urban areas. This review aims to establish a reference on NBS effectively applied and whose environmental, social, and economic benefits have been duly discussed. The results address 13 NBS techniques/methodologies implemented and their ecosystem benefits. Our findings suggest that the multifunctional nature of NBS makes it challenging to categorize environmental services and social benefits since there are multiple interactions and scales among the various benefits of NBS. Most studies have made greater efforts in approaches that use modeling, test benches, and/or laboratory facilities. However, although they work well for their purposes, there is no guarantee that the benefits will be maintained when applied on a full scale. We concluded that only a few studies scientifically evaluated the performance of installed NBS infrastructures, almost all in developed countries. [ABSTRACT FROM AUTHOR]

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Hawassa is a rapidly developing city in Lake Hawassa watershed of Ethiopia. Analyzing the effect of land cover dynamics on surface runoff remains imperative to adaptive urban stormwater management. This study quantified spatial variation of land cover and sensitivity of stormwater management response. Historical 30 years of daily annual rainfall, three satellite imageries, DEM, and hydrological soil group data were analyzed. A statistical‐based combined approach of geospatial techniques and Soil Conservation Service‐Curve Number (SCS‐CN) model was employed. CN and surface runoff depth for the delineated urban watersheds were determined. The result revealed that the built‐up area increased by 30.9 km2, where the rate varies spatially. The variation of impervious land cover explains 58.6% of change in CN with coefficient of 0.352. While CN is inversely correlated with agricultural and vegetation land cover variations. The finding suggests CN explains 96.78% of the change in surface runoff with a significant correlation coefficient of 3.91. The proposed integrated model approach justifies the potential to reorganize the relationship between the spatial effect of land cover variation on surface runoff at the urban watersheds. Thus, suitable local‐specific solutions can be devised for effective management of flood risk and optimize the drainage system of urban areas. [ABSTRACT FROM AUTHOR]

In Iran, particularly in the Zagros forests, natural land uses are increasingly being converted into agriculture, which can negatively influence soil hydrological processes. To study this, three replicate micro-plots were installed on similar slopes in the forest (FO), rangeland (RA), and vineyard ‒ under the canopy (VUC) and in the inter-row space (VIR) ‒ to measure soil loss and surface runoff. Top- and sub-soil samples were randomly taken in three replicates from three sites for each land use/cover (LUC). Standard laboratory methods were utilized to measure the designated soil properties. According to the results, soil organic matter (SOM), aggregation indices, residual (ϴr) and saturated water content (ϴs), water content at field capacity (ϴFC), and saturated hydraulic conductivity (Ks) showed a significant decreasing trend as follows: FO > RA > VUC > VIR, whereas EC, pH, CaCO3, bulk density, and K-factor significantly showed an increasing opposite trend. LUC did not affect permanent wilting point (ϴPWP), available water content (AWC), and α and n van Genuchten's parameters. It was also found that RA and FO exhibited a higher repellency index than VUC and VIR. The forest had the lowest soil loss and runoff due to its higher porosity, SOM, aggregate stability, infiltration rate, water storage capacity, and surface cover. The highest soil loss and runoff were observed in VIR because of the vineyard's management operations and the bareness of soil between the vine rows. Conservation measures, such as no-tillage, mulching, or cover crops in the inter-row spaces, are recommended to mitigate these negative effects. [ABSTRACT FROM AUTHOR]

To control and improve the phenomena of rocky desertification and soil erosion in karst landform areas, which are caused by a series of human factors that include social and economic development and human activities, China has successively introduced many policies, resulting in spatial and temporal changes in the landscape pattern of the southern karst area. In this study, land use transfer intensity maps, the grid method, the sample line method, the semivariogram method, and the Spearman analysis method are used to explore the spatial and temporal evolutions in surface runoff as responses to landscape pattern and policy factors in karst landform area. Therefore, this study provides theoretical and policy support for improving the regional landscape structure, optimizing the landscape layout, introducing regional policies, reducing surface runoff, and alleviating soil erosion. The results show that the best scale for the study of landscape patterns in the southern karst area is 3000 m. Forests are the land type that make up the highest proportion in the southern karst area, and they have the strongest interception capacity for surface runoff. The spatial and temporal distributions of the surface runoff are significantly different, and urban expansion has led to an increase in impervious runoff year over year. Runoff is positively correlated with the Shannon diversity index (SHDI), patch density (PD), and landscape shape index (LSI). The stronger the landscape heterogeneity, the more runoff. DIVISION is positively correlated with forest runoff and negatively correlated with other land types. The higher is the degree of aggregation of impervious patches, the higher the regional runoff rate. The more dispersed the forest patches are, the smaller the area proportion, and the greater the runoff. In addition, policy factors have a significant impact on surface runoff. [ABSTRACT FROM AUTHOR]

In recent years, global climate change has become more and more obvious, and extreme rainfall weather has occurred frequently, which has a serious impact on people's life and property safety. In order to reduce the risk of urban flooding and contribute to the sustainable development of the urban economy, society, and environment, this study takes Zhengzhou City as the study area. The surface runoff during extreme rainfall events from 2005 to 2023 was simulated using the SCS-CN model, and the spatiotemporal patterns of surface runoff during extreme rainfall conditions and their influencing factors were investigated. The results showed that (1) the average annual extreme rainfall in the study area was 95.6 mm, and the average annual surface runoff was 76.5 mm, with cultivated land contributing the most to surface runoff, accounting for more than 50%. The annual average frequency of extreme rainfall in the study area ranged from 0 to 3 times. (2) During the extreme rainfall events in 2021 and 2023, the surface runoff of the main urban area was relatively great. Under the influence of impermeable surfaces, the surface runoff of the main urban area was greater than that of the surrounding area, even when the rainfall in the main urban area was less than that in the surrounding urban area. In addition, during these two extreme rainfall events, the surface runoff in the slight slope (<5°) area was the greatest; overall, the larger the slope was, the smaller the surface runoff. (3) Differences between rainfall and surface runoff (DRS) of the different administrative districts in the study area showed three trends from 2005 to 2020, with those of most areas showing a clear decreasing trend, which was affected mainly by the surface runoff potential of the land use type. Under the same rainfall conditions (110 mm), the surface runoff of urban land and construction land was 1.4–2.5 times that of various types of woodland and grassland. From 2005 to 2020, the area of urban land and other construction land increased by 104.13%, the coverage area of woodland and grassland decreased by 35.90%, and the surface runoff potential increased in most areas of the study area. To reduce the risk of urban waterlogging, most areas of Zhengzhou, especially the main urban area and slight slope areas, need to rationally regulate land use and increase the coverage ratio of woodland and grassland. [ABSTRACT FROM AUTHOR]

The article focuses on using the MIKE SHE model to analyze the impact of land use and land cover (LULC) changes on streamflow in Ethiopia's upper Omo Gibe catchment. Topics include the effects of LULC changes on hydrological patterns, the application of statistical tests to identify trends and changes, and the implications for water management strategies in the region.

Copyright of Journal of the College Of Basic Education 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.)

The separation of streamflow into fastflow and slowflow components has been historically ambiguous, with existing separation methods like the Lyne-Hollick (LH) algorithm facing challenges due to subjective parameter choices. Here, we address this issue by developing the AutoVL algorithm which objectively and automatically partitions streamflow for no parameter input. AutoVL uses iterative statistical models, including a Signal Reconstructor for fastflow and an autoregressive moving-average (ARMA) model for slowflow, to estimate key hydrologic parameters. The algorithm couples the two models to iteratively estimate these parameters and to accurately separate streamflow. When applied to the Harvey River, Dingo Road station data, AutoVL identified significant seasonal and long-term variations in hydrologic parameters, reflecting the possible influence of climate change altering the temporal dynamics of catchment responses. The algorithm highlighted strongly coupled changes in infiltration and decay rates from altered streamflow patterns, offering a clearer understanding of streamflow responses to climate change. This performance suggests that AutoVL provides a more reliable, objective, efficient, and standard method for streamflow separation compared to previous approaches, enabling more accurate and confident hydrological modeling. By providing objective, dynamic insights into catchment behavior, AutoVL offers a promising tool for climate change studies and streamflow analysis.

ABSTRACT Soil steady water infiltration rate (SIR) is a key variable in hydrological modeling, but its relationship to antecedent soil moisture is not yet well understood. We tested the hypothesis that the SIR decreases with the increase in antecedent moisture, and that this relationship depends on permeability to water on the soil surface, the measurement method, and the measurement period. We conducted an experiment in an Argissolo Vermelho-Amarelo Distrófico abrúptico (Psammentic Paleudult – Soil Taxonomy), measuring infiltration in up to 14 antecedent moisture conditions under two soil structural conditions (no-till and no-till with subsoiling), with two measurement methods (double ring and Cornell infiltrometers), and for up to 48 h, with ten replications. In addition, vertical effective hydraulic conductivity of the saturated profile (Kef) was determined with Darcy’s equation for N layers. Crop succession used in the area was black oats and ryegrass in the winter and soybean in the summer. The SIR decreased to as little as 7.7 % of its original value with the increase in antecedent moisture; it was ~200 % greater in the treatment with subsoiling compared to no-till alone, and ~80 % greater when measured with the Cornell infiltrometer than with the double ring infiltrometer. Nevertheless, the effects of the method and the soil structural condition declined with the increase in antecedent moisture, confirming our hypothesis. In soil initially nearly saturated (degree of saturation ~90 %), the SIR drew near Kef (12.7 mm h-1) under the two soil structural conditions, especially when measured with the double ring infiltrometer. In contrast, increasing the time for measuring infiltration (>2 h) did not generate a new lower SIR level. The SIR decreases with the increase in antecedent soil moisture, and this relationship depends on the permeability to water of the surface layers and the measurement method. The SIR determined with infiltrometers better corresponds to vertical infiltration the nearer the soil is to saturation before beginning measurement.

Study region: This study focuses on the Ohio Region, which spans 11 states in the eastern United States. Study focus: Runoff coefficients are crucial in hydrology, indicating the relationship between rainfall and runoff. Understanding their controls and variability is essential for water resource assessment, management strategies, and land use planning. This research examines factors influencing runoff coefficients and their trends in the Ohio region using data from the North American Land Data Assimilation System phase-2 (NLDAS-2) Mosaic Land Surface Model, covering 2000–2020. The analysis considers short-term controls, such as climatic features (rainfall intensity, amount, and duration), hydrological factors (antecedent soil moisture, drainage density, and curve number), topographic factors (drainage area, land use, slope, elevation), and watershed shape. Additionally, the study investigates trends in runoff coefficients and their long-term controls, including climatic factors and land use changes. New hydrological insights for the region: The findings indicate that runoff coefficients increase with antecedent soil moisture and rainfall intensity. Higher elevations show lower runoff coefficients due to forested land use. Larger watersheds have lower runoff coefficients at low rainfall intensity but higher ones when intensity is high. Long-term trends reveal soil moisture as the primary control, with land cover changes as a secondary factor. This research deepens understanding of runoff coefficient dynamics and controls in the Ohio region. Future studies could explore the impacts of urbanization, reservoirs, evapotranspiration, and snowmelt on runoff coefficients.

Water is a critical natural resource, comprising approximately 60% of human body weight and playing a vital role in all physiological processes. However, water quality has deteriorated in recent years due to the presence of harmful contaminants, posing potential health risks. Hence, the objective of this paper is to assess the modelling runoff and sediment yield dynamics of the Upstream of Eleyele Lake Watershed, Oyo State, Nigeria using Geographic Information Systems (GIS) alongside the Soil and Water Assessment Tool (SWAT). The model's predictions indicated an annual surface runoff of 122.56 m³/s and a sediment yield of 26.02 t/ha within the study area. These levels suggest a significant risk of flooding and heightened susceptibility to soil erosion. Consequently, it is recommended that further modeling efforts be employed to identify erosion-prone zones with greater precision across the watershed, enabling the development of effective management strategies to mitigate these risks.

The Qinling Mountains, the so-called “central water tower,” are extremely important water resource hubs in China. The influence of the forest ecological environment on water quality is complicated. Therefore, to investigate the spatiotemporal variations in water quality, we employed a random forest model to integrate multiple key water quality indicators into one overall ranking value. Monthly monitoring data of surface runoff and atmospheric precipitation events (2003–2022) for the Huodigou stream in the Qinling Mountains were used. The results revealed that after atmospheric precipitation entered the forest ecosystem, the coefficients of variation of surface runoff for most of the selected indicators decreased, but there were significant differences among the six indicators (NO3−, Mg2+, Na+, pH, K+, Ca2+). Most of the indicators within surface runoff were positively correlated, such as those in atmospheric precipitation. However, some indices of surface runoff were negatively correlated with those of atmospheric precipitation, and there was a significant negative correlation between Ca2+ in atmospheric precipitation and Ca2+ in surface runoff and between NO3−in atmospheric precipitation and K+ and Na+ in surface runoff (p Mg2+ > Na+ > pH > K+ > Ca2+. Overall, our assessment revealed that from 2003 to 2022, the water quality grade in the Huodigou stream improved and was more stable. In summary, the forest ecosystem in the Huodigou stream has a significant water quality purification effect on the atmospheric precipitation it receives. Our novel criterion-based approach for categorizing the water quality of atmospheric precipitation and surface runoff offers a new tool for examining spatiotemporal stream water quality variations in the Qinling region and other mountainous areas.

BACKGROUND AND OBJECTIVES: Peak flow in watershed is important in designing and controlling soil erosion, as well as assessing the potential water yield. It also serves as a basis for assessing and managing the risk of environmental damage. However, there is no accurate information on peak flow to ensure sustainable management and conservation of Wuno Sub-Watershed in Palu Watershed which serves as a buffer for the capital of Central Sulawesi Province. Therefore, this study aimed to assess and determine the potential runoff and peak flows in watershed using soil conservation service-curve number.METHODS: Soil conservation service-curve number method was calculated to analyze rainfall from runoff as a function of cumulative rainfall, land use, soil type, and humidity. This method was developed by the United States Soil Conservation Service in 1972 and applied in this study with due consideration for several variables, including (a) land use classification and intensity for settlements, rice fields, plantations, rivers, etc., (b) basic physical conditions of the area such as rainfall and hydrology, as well as (c) classes of soil hydrology significantly influencing carbon-nitrogen value.FINDINGS: The result showed that carbón-nitrogen values for all types of land use or cover were in normal conditions from 5 to 25 years. Moreover, carbón-nitrogen range was observed to have significantly large quantitative consequences on direct runoff. The trend showed the need for precision and effectiveness in planning watershed management and conservation. Soil conservation service also had a positive influence on land use, specifically runoff, as observed in carbón-nitrogen values for return periods of 2, 5, 25, and 100 years. However, several other factors were identified to influence land use such as land cover and soil texture.CONCLUSION: Soil Conservation Service presented an analysis of how land use affected runoff, specifically with a focus on carbon-nitrogen values. Land use was not only affected by carbon-nitrogen values but other factors such as land cover and geomorphometric properties. The trend showed the need for a more comprehensive exploration of soil conservation service-curve number method in accurately predicting runoff patterns in sub-watershed areas to ensure effective and sustainable management and conservation practices.

Abstract Sewage sludge (SS) application to forest plantation soils as a fertilizer and/or soil amendment is increasingly adopted in plantation forest management. However, the potential risks of SS-derived heavy metals (HMs) remain a concern. Many factors, including woodland slope may affect the risks, but the understanding of this issue is limited. This research evaluated the HMs migration via surface runoff, interflow, and sediments when SS was applied in woodlands of varying slopes. We conducted indoor rainfall simulations and natural rainfall experiments to clarify the effect of slope on the migration of HMs via runoff (including surface and interflow) and sediments. In the simulated rainfall experiment, HMs lost via sediments increased by 9.79–27.28% when the slope increased from 5° to 25°. However, in the natural rainfall experiment, when the slope of forested land increased from 7° to 23°, HMs lost via surface runoff increased by 2.38% to 6.13%. These results indciate that the surface runoff water on a high slope (25°) posed high water quality pollution risks. The migration of HMs via surface runoff water or interflow increased as the steepness of the slope increased. The total migration of Cu, Zn, Pb, Ni, Cr and Cd via sediment greatly exceeded that via surface runoff and interflow. Particles ≤ 0.05 mm contributed the most to the ecological risks posed by sediments. Cd was the main source of potential ecological risks in sediments under both experimental conditions.

Land use and land cover (LULC) change detection and its subsequent impact on hydrology are of significant importance in the field of urban planning and the sustainable management of water and land resources. The primary objective of this research work is to illustrate LULC map in a specific study area, which encompasses approximately 316.7 km² in the Noakhali region. Additionally, this study tries to examine the enduring impacts of LULC changes on surface runoff within the specified area. In order to achieve this goal, the analysis of LULC change trends in the region was conducted using Landsat OLI/TM data from 2000 to 2020. The analysis focused on five distinct classes: built-up land, vacant land, farmland, vegetation, and waterbodies. The research employs the Soil Conservation Service Curve Number (SCS-CN) model to evaluate the influence of LULC changes on surface runoff. Notably, the findings indicate a substantial increase in built-up areas from 1.05% in 2000 to 11.21% in 2020. This urban expansion is strongly correlated with a notable rise in surface runoff, as evidenced by a high correlation coefficient (R2 = 0.98) between urban expansion and modelled runoff depth. The observed increase in impervious urban areas contributes to a 2.65% rise in average runoff from 2000 to 2020, equivalent to an 8.96 mm increment in average runoff. The study underscores the profound implications for managing urban storm floods and designing urban areas, especially in rapidly expanding cities globally, with a focus on developing nations. The insights gained offer valuable information for informed decision-making in sustainable urban development and water resource management, not only in the Noakhali region but also beyond.