Harmful cyanobacterial blooms disrupt aquatic ecosystem processes and biological functions. However, studies focusing on the effect of cyanobacterial blooms on the functional diversity of consumers are still insufficient. To examine the interactions of cyanobacterial blooms and the diversity and composition of metazooplankton, we investigated the variation in metazooplankton and their driven variables during the cyanobacterial bloom and non-bloom periods in 2020 and 2021 in Lake Xingkai. We found that cyanobacterial blooms reduced the metazooplankton species diversity but increased their biomass, functional dispersion, and functional evenness. Generalized additive mixed model results revealed that cyanobacteria showed different effects on metazooplankton biodiversity and functional diversity during the bloom and non-bloom periods. Variance partitioning analysis indicated that cyanobacteria, physicochemical variables, and temporal variation explained 15.93% of the variation in metazooplankton during the bloom period and 20.27% during the non-bloom periods. Notably, cyanobacteria during the bloom period explained more variations in metazooplankton composition than those during the non-bloom period. Our results suggest that cyanobacterial blooms significantly impact the functional diversity and community composition of metazooplankton. Physicochemical and spatiotemporal factors may mask the effects of cyanobacteria on metazooplankton. Our findings may improve the understanding of the dynamics and responses of metazooplankton communities to environmental changes and cyanobacterial blooms disturbances and enhance our ability to assess the effectiveness of aquatic ecosystem restoration and eutrophication management. Full article

This study aims to explore a preparation method based on a combination of melting and ultrasound to produce a Ga₂O₃/ZnO (GZ) spherical composite with a snake raspberry structure for the degradation of methyl orange at room temperature in dark. The catalyst exists in the form of a (GZ) composite and an anhydrous ethanol mixture after the ultrasonic treatment of premelted GaZn liquid metal alloy in anhydrous ethanol. The degradation activity of the catalyst was evaluated according to the amount of catalyst, alloy extraction temperature, acid–base environment, and inorganic salt ions. A transmission electron microscope (TEM) was used to confirm that the material was Ga₂O₃ coated with ZnO, with a structure similar to that of snakeberry. The electron paramagnetic resonance (EPR) and a series of free radical inhibition experiments demonstrated that ·O²⁻ is produced during the ultrasonic preparation of the catalyst and plays an important role in the degradation process after adding MO. The removal rate of MO reached 99.75% at 3 min. Three possible degradation pathways were proposed based on the intermediates produced during the degradation process, which were identified by liquid chromatography–mass spectrometry (LC–MS). The results of this study may provide a new choice for the degradation of organic pollutants. Full article

Groundwater-dependent terrestrial ecosystems (GWDTE) have been increasingly under threat due to groundwater depletion globally. Over the past 200 years, there has been severe artificial drainage of low-lying areas in Denmark, leading to a gradual loss of GWDTE nature habitat areas. This study explores the spatial-temporal loss of Danish GWDTE using historical topographic maps. We carry out geographic information systems (GIS) overlap analysis between different historical topographic maps with signatures of GWDTE starting from the 19th century up to a present-day river valley bottom map. We then examine the changes in two protected GWDTE habitat types in different periods and hydrologic spatial locations. Results reveal a decrease in the area of GWDTE over the last 200 years. We attribute this to different human interventions, e.g., drainage, that have impacted the low-lying landscape since the early Middle Ages. We further conclude that downstream parts of the river network have been exposed to less GWDTE habitat loss than upstream ones. This indicates that upstream river valleys are more vulnerable to GWDTE decline. Therefore, as a management measure, caution should be exercised when designing these areas for agriculture activities using artificial drainage and groundwater abstraction, since this may lead to further decline. In contrast, there is a higher potential for establishing constructed wetlands or rewetting peatlands to restore balance. Full article

The acoustic method, which enables continuous monitoring with great temporal resolution, is an alternative technique for detecting bedload movement. In order to record the sound signals produced by the impacts between gravel particles and detect the bedload motion, in this study, a hydrophone is placed close to the riverbed at the upper Yangtze River. Three categories of raw audio signals—moving gravel particles, ship engines, and flow turbulence—are collected and investigated. Signal preprocessing is performed using spectral subtraction to reduce the noise of the background sound, and the sound signal characteristic parameters are then calculated. In this paper, we propose a novel method for detecting and extracting bedload motion parameters, including peak frequency, pitch frequency, and energy eigenvector. When a segment of a speech signal meets the indicators for all three feature parameters simultaneously, the segment signal is classified as a bedload motion sound signal. Further work will be conducted to investigate bedload transport using the extracted audio signal. Full article

Aquatic environmental problems, such as algae, turbid water, and poor oxygen content, have become increasingly common. In river analysis, hydrological and water quality characteristics are used for evaluating aquatic ecological health, which necessitates continuous monitoring. In addition, because measurements are conducted using a fixed measurement method, the hydrological and water quality characteristics are not investigated for the entire river. Furthermore, obtaining high-resolution data is tedious, and the measurement area and time are limited. Hence, low-resolution data acquisition is generally preferred; however, this requires an appropriate interpolation method to obtain a wide range of data. Therefore, a 3D interpolation method for river data is proposed herein. The overall hydraulic and water quality information of a river is presented by visualizing the low-resolution measurements using spatial interpolation. The Kriging technique was applied to the river mapping to improve the mapping precision through data visualization and quantitative evaluation. Full article

Water scarcity in arid regions increases the need for technologies to improve water productivity. The integrated effects of plastic film mulching and water stress on grain maize under conventional and alternate furrow irrigation methods are still poorly understood in Sindh’s climate. Therefore, field trials were conducted at Malir farm, Sindh Agriculture University Tandojam, Pakistan, during the cropping season 2020–2021 to investigate whether mulching is practicable for grain maize production under the different furrow irrigation methods. The experiments involved two types of furrow irrigation, two water stress levels (sufficient and severe water stress), and plastic film mulching. Treatments were laid out in a randomized block design and three replications. The conventional and alternate furrow irrigation method was assigned to the main plot, while the water stress and plastic film mulching were in sub-plots. The results showed that different furrow irrigation methods significantly affected plant growth, grain yield parameters, and crop harvest index. Significant highest plant growth and grain yield of maize crop were observed with the conventional furrow irrigation (CFI) compared with the alternate furrow irrigation (AFI) method. However, grain yield and irrigation water productivity (IWP) were increased significantly by the plastic film mulching. The results revealed that sufficient water stress was more effective in sustaining grain yield and IWP than crop irrigating at several water stresses. The interaction effect of furrow irrigation and water stress, furrow irrigation, and plastic film mulching significantly impacted the IWP of grain maize. The IWP of the maize crop was significantly higher under the AFI than the CFI method if it was mulched with plastic film and irrigated at sufficient water stress level. Full article

Heavy metals and pharmaceuticals have polluted agricultural soils mainly through wastewater irrigation, fertilizers, and soil amendment with sewage sludge. This study aims to determine the synergetic toxic effect of Cd and the selected macrolide antibiotic, azithromycin (AZI), on ammonia-oxidizing bacteria (AOB) in soil, via analyzing nitrification inhibition. A short-term acute toxicity test was used to measure the formation of Nitrite (NO₂-N) to indicate the nitrification potential of the aerobic nitrosomonas bacteria in the germination period. Potential nitrification rates (PNRs) of five soil samples ranged between 3.782–17.642 mg NO₂-N/kg dm PNRs of soil samples positively correlated with organic matter content and neutral pH. PNRs of the tested soils were significantly affected by Cd and AZI contamination, with interactions exhibited for their simultaneous occurrence and soil pH. A significant difference (p < 0.05) was found when soil samples with pH 6.5–pH 8.5 contaminated with environmentally relevant concentrations of Cd (1 mg/kg–21 mg/kg) and AZI (1 mg/kg–9 mg/kg). 50% PNR inhibition after 11 mg/kg Cd and 5 mg/kg AZI contamination was determined for the soil sample at pH 8.5, with 3.782 mg NO₂-N/kg dm potential. From these outcomes, it was concluded that there was a risk of the soil nitrification process in case of simultaneous occurrence of Cd and AZI. Full article

The role of groundwater (GW) discharge on surface water (SW) quantity, quality and temperature is known to be important. Moreover, the effect of GW contributions to river thermal budgets is critical in natural rivers considering that water temperature plays a vital role in fish survival during extreme heat events. The identification of zones with GW input in rivers can, thus, help river management plans. However, detecting these zones at the watershed scale can be a challenge. This work combines thermal infrared (TIR) imagery of rivers and water sampling for radon measurements for better documentation of GW in rivers. The Sainte-Marguerite and Berard Rivers, both located in Quebec, Canada, are known for their abundance of salmonids. Their water temperature profiles were plotted using TIR imagery, and five cooling zones in the Berard River and two for the Sainte-Marguerite River were identified in which notable GW–SW exchange was the suspected cause. Radon concentrations measured within the cooling zones showed clear GW contribution to SW. TIR imagery is an effective and fast way to identify GW seepage at the watershed scale. Radon can be used as a complementary natural tracer of GW in rivers at finer scales. The combination of both methods was shown to be reliable for the identification of GW in rivers. This can help for a better anticipation of GW effects in management plans to deal with extreme heat waves that are predicted to occur more frequently under future climate change scenarios. Full article

Water quality is a major concern globally and in headwater catchments of developing countries it is often poorly managed. In these catchments, having scarce and heterogeneous information hinders the development of water quality assessments and predictive models to support management. To address this issue, the authors propose a framework of three stages that allows for: (i) conducting a comprehensive assessment of water quality; (ii) the development of a mountain stream water quality model based on said assessment; and (iii) the simulation of scenarios with the model to resolve conflicts between uses and quality of water. The framework involves multivariate analyses of principal components and clusters and follows a novel modeling protocol mainly designed for mountainous streams in developing countries. Applied to an Andean catchment in Colombia, the first stage of the framework revealed the catchment’s most significant water quality constituents and the most polluted season. The problematic constituents in this catchment include pathogens, nutrients, organic matter, and metals such as the highly toxic Cr and Pb, while water pollution is the highest during the driest months of the year (i.e., January to March). In the second stage, the model was calibrated reproducing the concentrations of pathogens, organic matter, and most nutrients, and showed a predictive capacity. This capacity was measured with an objective function to be minimized based on a normalized root mean square error. It increased only 14% when verified with a different dataset. In addition, during the third stage of the proposed framework, the simulation of alternative scenarios showed that centralized treatment is not sufficient to make water safe for potabilization and agriculture in the catchment. For this reason, improving water quality in the sub-basins at the highest altitudes is required. The proposed framework can be applied in other headwater catchments where information is limited, and where an improved management of water quality is needed. Full article

The performance of most urban drainage systems is adversely affected by unintended connections of groundwater and surface water, often denoted as inflow and infiltration (I&I). Various methods exist to locate and characterise these effects. Yet, it remains difficult to quantify them accurately, especially in terms of spatial distribution over a larger drainage area. One of the reasons for this is the lack of sufficient high-quality sewer flow measurements at a high temporal resolution, which would enable the calibration of detailed spatio-temporal relationships between rainfall and I&I flows. In this paper, a methodology is presented for deriving sewer flow time series from operational measurements at pumping stations, and the results from four pilot locations are discussed. It shows the potential of the methodology to be implemented at a large scale and to contribute to a better understanding and remediation of I&I in urban drainage management planning. Full article

The perennial herbaceous forage crops’ (PHFC) biomass as bioindustry feedstock or source of nutrients for ruminants is very important from their final utilization point of view. In 2022, the AquaCrop-FAO version 7.0 model has been opened for PHFC. In this context, this study aimed to test for the first time the ability of the AquaCrop-FAO model to simulate canopy cover (CC), total available soil water (TAW), and biomass (B) of Guinea grass (Megathyrsus maximus cv. Agrosavia sabanera) under different water regimes at the Colombian dry Caribbean, South America. The water regimes included L1—irrigation based on 80% field capacity (FC), L2—irrigation based on 60% FC, L3—irrigation based on 50% FC, L4—irrigation based on 40% FC, L5—irrigation based on 20% FC, and L6—rainfed. The AquaCrop model uses the normalized water productivity—WP* (g m⁻²)—to estimate the attainable rate of crop growth under water limitation. The WP* for Guinea grass was 35.9 ± 0.42 g m⁻² with a high coefficient of determination (R² = 0.94). The model calibration results indicated the simulated CC was good (R² = 0.84, RMSE = 17.4%, NRMSE = 23.2%, EF = 0.63 and d = 0.91). In addition, cumulative biomass simulations were very good (R² = 1.0, RMSE = 5.13 t ha⁻¹, NRMSE = 8.0%, EF = 0.93 and d = 0.98), and TAW was good (R² = 0.85, RMSE = 5.4 mm, NRMSE = 7.0%, EF = 0.56 and d= 0.91). During validation, the CC simulations were moderately good for all water regimes (0.78 < R² < 0.97; 12.0% < RMSE < 17.5%; 15.9% < NRMSE < 28.0%; 0.47 < EF < 0.87; 0.82 < d < 0.97), the cumulative biomass was very good (0.99 < R² < 1.0; 0.77 t ha⁻¹ < RMSE < 3.15 t ha⁻¹; 2.5% < NRMSE < 21.9%; 0.92 < EF < 0.99; 0.97 < d < 1.0), and TAW was acceptable (0.70 < R² < 0.90; 5.8 mm < RMSE < 21.7 mm, 7.6% < NRMSE < 36.7%; 0.15 < EF < 0.58 and 0.79 < d < 0.9). The results of this study provide an important basis for future research, such as estimating biomass production of high-producing grasses in tropical environments, yield effects under scenarios of climate variability, and change based on the presented parameterization and considering a wide range of environments and grazing variations. Full article

In the face of ongoing anthropogenic climate change, river water quality assessment has become increasingly important for maintaining ecological balance and supporting local and downstream livelihoods. This research aims to create a new water quality index (WQI) to assess water quality in the Andean highlands (>2000 m.a.s.l.) for climate change adaptation and mitigation. We examined water physicochemical and bacteriological parameters and the benthic macroinvertebrate (BM) community in three micro-watersheds in Achupallas, Ecuador, to achieve our goal. We analyzed water quality at 41 sampling points, and samples (replicates) were taken for nine consecutive months. In addition, we evaluated the accuracy of the WQI developed by the U.S. National Sanitation Foundation (NSF) in 1970 (WQI_NSF). The BM community in the Andes highlands was used to develop and calibrate a new WQI, the Andean Biotic Index* (ABI*). We calibrated the ABI* taxon score in the area where the WQI_NSF made the most accurate water quality measurements. Our results show that the sigma value framework quantifies WQI_NSF accuracy. Therefore, a higher sigma value means we measured water quality more accurately. There was no correlation between the WQI_NSF and the Andean Biotic Index (ABI). The ABI* considers the presence of BMs and their sensitivity to pollution to measure water quality. The results also show a strong statistical link between the ABI* and the WQI_NSF. The ABI* can aid mountain communities in adjusting to climate change. Mountain dwellers can monitor a stream’s water quality by observing the BM communities. However, the ABI* is not a substitute for the WQI_NSF or biological studies. Full article

A long-term (1933–2022) record of water level (WL) fluctuations in Lake Kinneret was reviewed. The dependence of the Kinneret WL management on climate change (flood–dryness alternate), dam and National Water Carrier (NWC) constructions constrained by water availability and domestic supply demands were indicated. A short-term range of maximal WL decline of 4–6 m and 4.6–6.5% of the total surface area of lake water shrinkage in Lake Kinneret was documented. Nevertheless, incomparably longer periods and higher amplitudes of WL decline accompanied by a dramatic shrinking of the water surface were documented in Lake Tchad, the Aral Sea and Lake Sivan (SAT). Therefore, the comparative results of WL decline in Lake Kinneret and in other lakes as SAT are not justified. Full article

The 8006 working face at the Wuyang Coal Mine adopts grout injection into bed separation technology for surface subsidence control. Surface grout leakage occurred during the grout injection into the bed separation process of this working face. Grout leakage has adverse effects on the grouting filling effect, grouting cost and the environment. To determine the grout leakage channels and the slurry transport process, and to provide a theoretical basis for slurry leakage prevention and control, this paper first used 3D seismic exploration technology to identify the fault distribution characteristics of the study area, and then used COMSOL Multiphysics to carry out the numerical simulation of the grout transport process. The conclusions are as follows. Fifteen normal faults were identified in the vicinity of the 8006 working face. Among all the faults, the F1, F11, F18, F19 and F27 faults penetrate the surface and are the main channels for the grout to run to the surface. Based on the distribution characteristics of the faults and the spatial location relationship among the bed separation, faults and grout leakage points, the theoretical analysis of the leakage causes of each grout leakage point was carried out, and the main leakage channels of the grout injection into bed separation were proposed to be the bed separation and faults. The results of the numerical simulation of grout transport show that, as the permeability of the bed separation space and fault is much better than that of the surrounding rock, during the grout injection process the grout diffuses through the bed separation and fault in turn, and finally to the surface, where leakage occurs. The simulation results confirm that the main leakage channels for the grout are bed separation and faults. Full article

Water quality deterioration is a major problem faced by reservoirs globally, owing to the inflow of pollution from industrial and municipal activities. Water-lifting aeration is an in situ water quality improvement technology that mixes and oxygenates deep water bodies in reservoirs to improve pollution control efficiency and water quality. While previous studies have mainly focused on the mixing process in the reservoir outside the water-lifting aerator (WLA), knowledge of the internal flow remains limited. In this study, a two-phase flow within a WLA system was numerically studied using the volume of fluid (VOF) method to comprehensively analyze the internal two-phase flow characteristics and the influence on the water-lifting and oxygenation performance of the system. The statistical analysis results showed that increasing the aeration chamber volume enhanced the bottom oxygenation performance by 27% because of the prolonged time of the deflector plate outlet outflow. Additionally, increasing the air release rate enhanced the water-lifting performance by 47%, which was induced by the shortened air piston release period. This study demonstrates the internal flow mechanism of the WLA and provides technical support for parameter optimization design, which has significant scientific research and engineering application value. Full article