Stormwater control measures (SCMs) are technical elements designed to prevent and mitigate the negative effects of uncontrolled stormwater runoff. Different types of SCM can provide various co-benefits to the surrounding urban environment, making it important to select the most appropriate measure. This study presents a multi-criteria decision analysis (MCDA) framework for evaluating SCMs based on their optimized design parameters. Six SCM types – bio-retention cells, rain gardens, green roofs, infiltration trenches, detention ponds, and storage tanks – were optimized for a single objective: catchment outflow reduction. The resulting designs were evaluated using MCDA, incorporating additional performance criteria including capital expenditure (CAPEX), operating expenses (OPEX), land take, retained water, detained water, and plant space. The compromise programming method was applied to rank SCM scenarios based on their proximity to an ideal solution. Results indicate that landscape-integrated SCMs, particularly detention ponds, offer the most balanced performance, combining low costs with high co-benefits. Building-integrated SCMs, such as green roofs and rainwater-harvesting storage tanks, scored moderately, while underground storage tanks – representing grey infrastructure – performed the worst due to high costs and lack of co-benefits. The proposed evaluation framework enables transparent, criteria-based comparison of SCMs and supports informed decision-making in urban stormwater planning.

Increasingly frequent floods demonstrate the vulnerability of bridges and their piers. Designing a pier involves determining its drag coefficient C_d. In the existing literature, C_d is given as a function of the Reynolds number Re, i.e. C_d=f(Re), while the present study also investigated C_d as a function of the Froude number Fr, i.e. C_d=f(Fr). The SPH method and the model DualSPHysics were used to simulate three-dimensional turbulent free-surface flows past a surface-piercing cylinder in a straight horizontal channel. Subcritical, critical, and supercritical flows with Fr<2 were examined. The model was calibrated for flows in a duct filled with water (i.e. flows without free water surface) and validated against open channel experiments from the literature. Finally, the model was used to simulate real-life high-discharge conditions. Determination of C_d=f(Fr) indicated that the constant value of C_d as defined in the Eurocode 1 standard is not necessarily optimal.

This study examines hydrological processes at the Zelenjak (1958–2023) and Rakovec (1926–2022) stations on the Sotla/Sutla River, analyzed on an annual time scale. The analysis includes time series of annual minimum and maximum mean daily flows and mean annual flows. Additionally, data on annual precipitation and mean annual temperatures measured at the climatological station Bizeljsko in the period 1951 to 2024 were used to calculate annual runoff coefficients at the Zelenjak and Rakovec stations. The New Drought Index (NDI) was calculated using precipitation and air temperature data measured at the Bizeljsko climatological station. All analyses indicated a strong variability of the analyzed parameters over the available data period. A clear downward trend in mean annual flows is observed. In the recent period, from 2000 onward, there has been a sharp increase in mean annual air temperatures and a decline in all other analyzed hydrological and climatological parameters. Particularly concerning is the notable rise in the frequency and intensity of droughts in the 2000–2024 period. The causes of these trends could not be reliably determined through an analysis conducted on an annual time scale. It appears that natural factors, particularly the sharp rise in air temperatures, have played a significant role. However, it is important to emphasize that the natural characteristics of the Sotla/Sutla River basin have, to date, remained largely unaffected by human interventions. Furthermore, the insufficient accuracy in defining peak flows must be considered, as the rating curves used to define maximum flows may not have been reliable in certain periods.

The kinematics of flow movement in the forebays of pumping stations significantly influence the efficiency of pump operation. This study addresses the issue of sediment accumulation caused by improper flow velocity distribution in the intake structures of pumping stations. Research was conducted at the water intake structure of Uzbekistan’s Dehqonobod pumping station, located in Quva district, Fergana region. The study involved analyzing hydrodynamic processes within the intake structure based on the principles of fluid motion, combining experimental approaches with simulations using the COMSOL Multiphysics software suite to develop a 3D structural model of the prototype intake structure. Additionally, numerical simulations were performed using the Newton-Raphson scheme and the realizable k-ε turbulence model for comparative analysis and evaluation. To ensure proper flow velocity distribution, six vertical columns were arranged in a triangular pattern relative to the flow movement, with a spacing of 1 meter between them. This arrangement was proposed so as to enhance technical and economic efficiency. The results of the study demonstrated that the installation of vertical columns increased the flow velocity near the right and left walls of the forebay, achieving a variation in velocity distribution of up to 20%. Specific recommendations were developed to optimize the hydrodynamic conditions and improve the pumping station's operational efficiency.

Rainfall, with its varying timescales, impacts weather patterns, living conditions, and the environment. This study aims to evaluate trends and structural shifts in monthly rainfall across 24 locations in Nigeria spanning 51 years (1960-2010). Utilizing the Mann–Kendall test statistic (MK) for trend identification and the cumulative sum method for detecting changes in structure, cyclic patterns, and random components within distributions, the analysis incorporated descriptive statistics, including the coefficient of variation, skewness, kurtosis, and the Jarque–Bera test with associated p-values. Descriptive statistics can behave unusually where abnormal rainfall patterns are common. Despite the nonparametric nature of MK, it occasionally yielded varying values and dissimilar trends between total annual rainfall and total seasonal rainfall, as well as between average annual rainfall and average seasonal rainfall, attributed to high variability. Consequently, a statistically significant trend in total rainfall amounts might not correspond to the trend in mean rainfall amounts. Notably, statistically significant trends may sometimes be accompanied by similar significant structural shifts at every location. However, such trends and shifts are generally more frequent in the northern arid regions, specifically between 9.14°N and 12.53°N. For instance, a statistically significant change in total annual rainfall of 11.15 mm/year was observed in Kano (12.03°N), accompanied by an increasing structural shift around the 40th year of analysis. Conversely, a total annual rainfall significant trend of -3.01 mm/year occurred at Jos (9.52°N), though it was not among the 9 locations with significant structural shifts. Analysis of this nature helps in tackling water-related issues and understanding atmospheric phenomena.

Centrifugal cyclones have been developed for centuries to treat process streams, but their efficiency in removing fine dust remains below 80%. The widespread use of cyclones in various industries is the result of their simplicity in design and their reliable operation. However, the process occurring inside a cyclone is a complex scientific problem that still remains unsolved within the framework of aerohydromechanics, as evidenced by the variety of cyclone designs. The current level of cyclone cleaning's efficiency for process streams does not meet sanitary standards and significantly affects the level of environmental pollution. This paper compares various configurations of centrifugal cyclones, including cyclones without screws, with a screw of a uniform pitch, and with a screw of a variable pitch to regulate the twist of the flow. Numerical simulations were performed using the Comsol Multiphysics 5.6 software package using the SST turbulence model. The obtained numerical data show that the efficiency of a cyclone with a variable screw pitch is significantly higher than that of cyclones without screws and with a screw of a uniform pitch.

Historically, floods have posed significant risks to human society and the environment, resulting in substantial humanitarian, environmental, and economic losses. In recent decades, global flood events appear to have increased in frequency. Modern approaches to flood risk management include infrastructure protection, resource-efficient management, and insurance programs. However, these protective mechanisms are only effective when based on robust scientific methods and fostered through interdisciplinary collaboration. Effective decision-making requires diverse and comprehensive data, which is often lacking. Paradoxically, some protective measures can be counterproductive, occasionally resulting in more damage than if the floodwaters had been left to follow their natural pathways. This paper provides an in-depth analysis of floodplain management and levee systems in controlling flood risks. It also examines approaches such as "space for the river" concepts, nature-based solutions, and river restoration initiatives to mitigate flood impacts. Additionally, the Jubilee Bypass Channel, an artificial river designed to protect parts of London from flooding, is presented as a case study. Ultimately, this paper concludes that a fully risk-free flood protection system is an unattainable goal. However, floods offer ecological benefits, notably in enhancing biodiversity and soil fertility. As such, this study reviews various flood control strategies, innovative concepts, and international initiatives dedicated to minimizing flood damage and prioritizing the protection of human life.

The river channel cut into an alluvial substrate constantly adapts to changes in water flow and sediment transport. This paper presents a new approach to determine the magnitude of channel deformation based on the definition of dimensionless spatial parameters of channel deformation. The new approach’s applicability is evaluated by experimental studies on the Željeznica River in the Sarajevo Field in central Bosnia and Herzegovina. The morphological changes of the channel over a period of ten years were analyzed using dimensionless parameters of the channel geometry. A numerical analysis of changes in the channel of the Željeznica River was carried out using a mathematical model and a selected equation for sediment transport. Sensitivity analysis of the model parameters for channel deformation and statistical reliability analysis of the numerical model showed a good agreement between the modeled and observed values of channel deformation parameters during the analyzed period.

River discharges play an important role in understanding mercury fate in contaminated catchments. While hydrological and hydraulic models are commonly used to calculate discharges, their complexity and computational costs often pose challenges. This study evaluates the fit of the statistical curve and one of the machine learning methods, namely model trees, and explores their performance in predicting downstream river discharges based on upstream discharge measurements. The model trees method performs better, particularly with high discharges, which transport the vast majority of mercury downstream. The resulting relationships can be used as an input to various models assessing the impact of mercury pollution from the former mine in Idrija and the climate change on mercury transport in the river systems of the Idrijca and Soča/Isonzo rivers. The application of such models will improve our understanding of mercury cycling in the contaminated catchment and in the Gulf of Trieste’s coastal environment.

This paper presents analyses of the impact of various scenarios involving increases in mean sea levels due to climate change on the characteristics of sea flooding and the expected flood damage in the area surrounding the town of Piran, Slovenia. Taking into account the various scenarios of mean sea level rise, we have determined the extent of inundated areas and water depth in the coastal area under consideration. The KRPAN model was used to analyze the exposure risks facing the town’s residents and some of its spatial elements, as well as to estimate the flood damage for various scenarios of mean sea level rise. The results of the study show a likely dramatic increase in the probability that the current extreme sea flood events on the Slovenian coast will continue to occur, namely an approximately 2-fold increase in probability for every 10 cm of sea level rise. The expected annual damage for the current state is estimated at approximately €0.68 million/year, rising to €2.4 million/year in the event of an increase in the mean sea level of 30 cm by 2100, with most of the damage related to residential facilities. Considering the most pessimistic scenario of sea level rise, the annual damage is expected to increase to €10.2 million/year. Irrespective of the actual magnitude of the imminent mean sea level rise in the coming decades, the fact remains that without flood protection measures, flood damage in the Piran area will increase enormously in the future. The town will have to cope with the increasing consequences of sea flooding, which will have a major impact on the normal functioning of urban areas.