Water Management Measures Research Articles

Optimal Relationship Between As and Cd in Porewater of Paddy Soils with Variations in pe + pH: Insight from Trade-Off Value Analysis

The remediation of paddy soils co-contaminated with As and Cd is tricky. It is difficult to decrease Cd and As availability simultaneously due to their opposite geochemical characteristics. Finding the optimal trade-off relationship between As and Cd availability in paddy soils is a significant task that is necessary to guide the construction of water management measures. This study investigated the dissolution characteristics of As, Cd, Fe, Mn, DOC, DOM, and various As and Cd fractions in soils via the microcosm system and calculated the optimal trade-off value for available As and Cd in porewater. The results showed that the total As in porewater increased rapidly when the soil Eh was reduced to −104 mV. Meanwhile, the total Cd in porewater decreased dramatically when the soil Eh was below 62 mV. Under flooding and drainage conditions, Fe/Mn (oxyhydro)oxides play a vital role in regulating Cd dissolution in paddy soils, while Fe/Mn (oxyhydro)oxides organically bind sulfide together to determine the dissolution of As. Additionally, the optimal pe + pH response to the minimum trade-off value of available As and Cd in porewater was found to be 6.6, which indicates a moderate reduction status. Therefore, further research should apply the optimal pe + pH to construct water management measures to safely utilize co-contaminated paddy fields.

Subsidence and measures in the polders of the Netherlan ds

AbstractThe Netherlands consists for 65% of polders. Impoldering activities started in the beginning of the 11th century with impoldering of coastal lowlands. In the 13th century, a start was made with reclaiming of lands gained on the sea and since early 16th century with draining of lakes. Up to several metres in depth, soils consist primarily of peat and or clay. Underneath is a thick sandy layer, with lenses of clay. Especially in peat polders, subsidence and oxidation have been significant, up to 5 m, and is still going on. In clay polders, most of the subsidence took place in the first decennia after reclamation. Maximum subsidence in these polders has been 1.25 m. Over centuries, various measures have been taken to cope with the subsidence problems. These measures consist first of all in water management measures related to management not only of the subsidence process, but also of special measures with respect to buildings, structures and infrastructure. The paper presents a review of the subsidence process in the different types of polders, as well as of measures that over the centuries have been taken to cope with the developments in the polders and to cope with subsidence problems.

Spatial data modelling of atmospheric water availability and stress in Jharkhand, India

Due to climate and human activity, water supply in Jharkhand, India, fluctuates. This study measured AWS and AWA in Jharkhand, India. MODIS NDVI and Terra Climate data processed by Google Earth Engine (GEE) are used in the analysis. Based on mean annual values for NDWI, run-off, precipitation, and ET, AWS and AWA are categorised. Results show significant regional differences in ET, precipitation, runoff, AWS, and AWA in Jharkhand. Purbi Singhbhum has far higher ET rates than Garhwa, Palamu, and Chatra. High AWS levels in Sahibganj, Godda, Pakur, Garhwa, and Kodarma indicate serious water scarcity. Therefore, these locations need focused water management approaches. Different districts including Giridih, Chatra, Jamtara, Latehar, Simdega, and Hazaribagh have different levels of AWS, highlighting the need for individualised treatments. The AWA index helps resource managers make educated decisions by detecting water-scarce places. Climate variability affects temperatures and precipitation, worsening AWS in high-AWS areas. Water scarcity mitigation requires local infrastructure development and water management measures. To verify remote sensing data accuracy, future study should improve data resolution and include in-situ measurements. These findings can help policymakers and stakeholders in Jharkhand create efficient water resource management strategies to reduce water stress and assure water supply.

Hydro-geochemistry and age-dependent health risk assessment of nitrate, nitrite, and fluoride in health facilities water: a multivariate analysis.

Groundwater from alluvial fan plains is the prevailing water source, especially for arid/semiarid regions, but its contamination poses substantial risks to water supply and public health. The recent study aims to assess the hydro-geochemistry, distribution, and potential health risks of NO3-, NO2-, and F- concentrations in the groundwater of previously unexplored health facilities in District Vehari, Punjab, Pakistan. In total, 75 groundwater samples were evaluated for NO3-, NO2-, and F- levels as well as pH, EC, TDS, CO32-, HCO3-, Cl-, Na+, Fe, K+, Ca2+, Mg2+, taste, odor, color, and turbidity. The Durav graph shows that the water type is Na-HCO3-Ca, with Na and HCO3 dominant, weak acids > strong acids, and alkaline ions > alkalis. Results revealed that drinking water samples (21.73% and 20%) taken from Tehsil Mailsi, and the Basic Health Unit (BHU) exceeded the WHO standard (1.5mg/L) for F- concentration, respectively. Moreover, the mean chronic daily intake (CDI) of F- was 0.044, 0.018, and 0.02mg/kg/day in children, men, and women, respectively. Similarly, the average CDI of NO3- was 0.113, 0.046, and 0.050 in children, men, and women, respectively, and the respective values of NO2- were 0.004, 0.001, and 0.001. The NO2- shows a significant range of hazard quotient (HQ) (0.0-1.172) in children. The range of HQ for F- was 0.0-3.114, 0.0-1.290, and 0.0-1.389 in children, men, and women, respectively. Additionally, the health risks analysis revealed an HQ > 1.0 for children in groundwater, indicating a potential carcinogenic risk from the F-. Pearson correlation and PCA analysis found a significant positive correlation (0.8) between NO3- and NO2- and a negative correlation (0.3) between F- and HCO3-. These findings highlight the need for groundwater treatment in healthcare facilities prior to water consumption. Enforcing international and national drinking water standards in healthcare units is vital to strengthening services and providing equitable access to safe drinking water. Legislative and efficient water management measures must be taken for the protection of public health.

Effects of Water, Fertilizer and Heat Coupling on Soil Hydrothermal Conditions and Yield and Quality of Annona squamosa

Seasonal drought and summer soil high-temperature stress in Southern China often lead to decreased yield and quality of Annona squamosa. It is important to explore reasonable and effective water and fertilizer management measures as well as cover measures to improve the soil hydrothermal conditions in orchards to realize the increase in yield and quality of Annona squamosa. This study involved a two-year (2022–2023) field experiment in Yun County, Lincang City, Yunnan Province, using three factors and a three-level orthogonal test, resulting in nine different experimental treatments for water, fertilizer and heat. The three irrigation levels were W1 (soil moisture content of 55% of field moisture capacity), W2 (soil moisture content of 75% of field moisture capacity) and W3 (soil moisture content of 85% of field moisture capacity). The three fertilizer levels were F1 (1666 kg·hm−2), F2 (2083 kg·hm−2) and F3 (2500 kg·hm−2), and the three cover methods were A1 (no cover), A2 (fresh grass cover) and A3 (straw cover). The effects of these treatments on soil hydrothermal conditions, growth indices and fruit yield and quality of Annona s1uamosa were systematically monitored and analyzed, and the relationships between these treatments and yield and quality was analyzed based on a Mantel test. The results showed that T5 (W2F2A3) had the highest average soil moisture content over two years, followed by T7 (W3F1A3). The T7 (W3F1A3) treatment effectively reduced soil temperature by 5 °C compared to T1 (W1F1A1). T5 (W2F2A3) had the highest average yield over two years, with an increase of 33.99% compared to T1 (W1F1A1). Additionally, T5 (W2F2A3) has the highest average soluble solids, soluble sugars and vitamin C content over two years, with increases of 28.13%, 13.36% and 4.86%, respectively, compared to T1 (W1F1A1). A Pearson correlation analysis showed that there was a significant correlation between Annona squamosa growth and soil moisture content and soil temperature, and the Mantel test showed that soil hydrothermal conditions had significant influence on the growth and yield. T5 (W2F2A3) has the highest comprehensive benefit in promoting growth, increasing yield and improving quality for the plant. The effects of different irrigation quantities, fertilizer amounts and different cover measures on the coupling interaction for soil hydrothermal status in the root zone, growth, yield and quality of Annona squamosa were investigated, providing reliable theoretical support for the scientific planting model of Annona squamosa in the low-heat river valley of Yunnan Province.

New Report of Cyanobacteria and Cyanotoxins in El Pañe Reservoir: A Threat for Water Quality in High-Andean Sources from PERU.

Cyanobacteria are cosmopolitan organisms; nonetheless, climate change and eutrophication are increasing the occurrence of cyanobacteria blooms (cyanoblooms), thereby raising the risk of cyanotoxins in water sources used for drinking, agriculture, and livestock. This study aimed to determine the presence of cyanobacteria, including toxigenic cyanobacteria and the occurrence of cyanotoxins in the El Pañe reservoir located in the high-Andean region, Arequipa, Peru, to support water quality management. The study included morphological observation of cyanobacteria, molecular determination of cyanobacteria (16S rRNA analysis), and analysis of cyanotoxins encoding genes (mcyA for microcystins, cyrJ for cylindrospermopsins, sxtl for saxitoxins, and AnaC for anatoxins). In parallel, chemical analysis using Liquid Chromatography coupled with Mass Spectrometry (LC-MS/MS) was performed to detect the presence of cyanotoxins (microcystins, cylindrospermopsin, saxitoxin, and anatoxin, among others) and quantification of Microcystin-LR. Morphological data show the presence of Dolichospermum sp., which was confirmed by molecular analysis. Microcystis sp. was also detected through 16S rRNA analysis and the presence of mcyA gene related to microcystin production was found in both cyanobacteria. Furthermore, microcystin-LR and demethylated microcystin-LR were identified by chemical analysis. The highest concentrations of microcystin-LR were 40.60 and 25.18 µg/L, in May and November 2022, respectively. Microcystins were detected in cyanobacteria biomass. In contrast, toxins in water (dissolved) were not detected. Microcystin concentrations exceeded many times the values established in Peruvian regulation and the World Health Organization (WHO) in water intended for human consumption (1 µg/L). This first comprehensive report integrates morphological, molecular, and chemical data and confirms the presence of two toxigenic cyanobacteria and the presence of microcystins in El Pañe reservoir. This work points out the need to implement continuous monitoring of cyanobacteria and cyanotoxins in the reservoir and effective water management measures to protect the human population from exposure to these contaminants.

Simulation of Groundwater Dissolved Organic Carbon in Yufu River Basin during Artificial Recharge: Improving through the SWAT-MODFLOW-RT3D Reaction Module

To keep groundwater levels stable, Jinan’s government has implemented several water management measures. However, considerable volumes of dissolved organic carbon (DOC) can enter groundwater via water exchange, impacting groundwater stability. In this study, a SWAT-MODFLOW-RT3D model designed specifically for the Yufu River Basin is developed, and part of the code of the RT3D module is modified to simulate changes in DOC concentrations in groundwater under different artificial recharge scenarios. The ultimate objective is to offer valuable insights into the effective management of water resources in the designated study region. The modified SWAT-MODFLOW-RT3D model simulates the variations of DOC concentration in groundwater under three artificial recharge scenarios, which are (a) recharged by Yellow River water; (b) recharged by Yangtze River water; and (c) recharged by Yangtze River and Yellow River water. The study shows that the main source of groundwater DOC in the basin is exogenous water. The distribution of DOC concentration in groundwater in the basin shows obvious spatial variations due to the influence of infiltration of surface water. The area near the upstream riverbank is the earliest to be affected. With the prolongation of the artificial recharge period, the DOC concentration in groundwater gradually rises from upstream to downstream, and from both sides of the riverbank to the surrounding area. By 2030, the maximum level of DOC in the basin will exceed 6.20 mg/l. The Yellow River water recharge scenario provides more groundwater recharge and less DOC input than the other two scenarios. The findings of this study indicate that particularly when recharge water supplies are enhanced with organic carbon, DOC concentrations in groundwater may alter dramatically during artificial recharge. This coupled modeling analysis is critical for assessing the impact of recharge water on groundwater quality to guide subsequent recharge programs.

Spatial and temporal dynamic zoning of crop water consumption under past and future climate and socioeconomic changes in China

The impacts of multiple changes in climatic and socioeconomic conditions within countries and regions are spatially heterogeneous, thus complicating stringent agricultural water management. Here we developed a framework for the dynamic identification of zone types and provided targeted agricultural water management strategies for each zone in response to global change. Considering China as an example, eight zones of typical major grain crop production prefectures were identified based on an analysis of the spatial and temporal evolution characteristics at four levels (agricultural, natural, social, and economic) according to the water footprint of major grain crop production at the prefecture-level for the past 15 years (2004–2018). We then presented the response of China's future zoning landscape for 2030, 2050, and 2080 under three representative scenarios by combining shared socioeconomic paths (SSPs) and representative concentration paths (RCPs). Results show that, by 2080, the national water consumption of the major grain crop production will increase under all scenarios. Half of the prefectures facing function shifts are likely to change from low to high water-consuming zones. Different zonal prefectures react differently under global changes, especially those that are prone to functional transformation, and should pay attention to their instability. Consideration of the water footprint in agricultural zoning is of great importance for national sustainable water resources management. This study proposes a more explicit approach to coping with global change, that is, to propose regionalized and prior agricultural water management strategies and measures for China and beyond.

Forecasting Meteorological Drought Conditions in South Korea Using a Data-Driven Model with Lagged Global Climate Variability

Drought prediction is crucial for early risk assessment, preventing negative impacts and the timely implementation of mitigation measures for sustainable water management. This study investigated the relationship between climate variations in three seas and the prediction of December meteorological droughts in South Korea, using the Standardized Precipitation Evapotranspiration Index (SPEI). Climate indices with multiple time lags were integrated into multiple linear regression (MLR) and Random Forest (RF) models and evaluated using Pearson’s correlation coefficients (PCCs) and the Root Mean Square Error (RMSE). The results indicated that the MLR model outperformed RF model in the western inland region with a PCC of 0.52 for predicting SPEI-2. On the other hand, the RF model effectively predicted drought states of ‘moderate drought’ or worse (SPEI < −1) nationwide, achieving an average hit rate of 47.17% and Heidke skill score (HSS) of 0.56, particularly excelling in coastal areas. Nino 3.4 turned out to be the most influential factor for short-period extreme droughts (SPEI-2) with a three-month lag, contributed by the Pacific, Atlantic, and Indian Oceans. For periods of four months or longer, climate variations had a lower predictive value. However, integrating autocorrelation functions to account for the previous month’s drought status improved the accuracy. A HYBRID model, which blends linear and nonlinear approaches, further enhanced reliability, making the proposed model more applicable for drought forecasting in neighboring countries and valuable for South Korea’s drought monitoring system to support sustainable water management.

Fuzzy rule–based control of multireservoir operation system for flood and drought mitigation in the Upper Mun River Basin

Strategic reservoir operation, a primary water management measures, plays a significant role in mitigating floods and droughts. Since the reservoir operation involves making complicated decisions on uncertain hydrological variables driven by climate variability, therefore, constructive tool for decision making like fuzzy logic is essential to optimize reservoir management and ensure water security. This study demonstrated fuzzy logic application to multiple reservoir operation in tropical region like Thailand. A Fuzzy Rule–Based Model (FRBM) exploiting FL approach was developed to control the upstream reservoir operation in the Upper Mun River Basin (UMRB) using the data from 2008 to 2021. Implementing FRBM for UMRB was conducted by identifying two key variables; available water storage and 7–day ahead predicted inflow, as fuzzy inputs. The fuzzy output of the system is the release fraction determined by three operational condition modules; flood, neutral, and drought. For flood module, fuzzy release is primarily determined by the predicted inflow. However, the determination of reservoir release for drought and neutral modules is influenced by the targeted water demand. The results of base case illustrate the capability of FRBM in increasing reservoir storages at the start of dry season by 123.56 MCM/yr in UMRB due to the new daily release schemes generated. This allows supplying water closer to the theoretical agricultural needs and gross irrigation water requirement potentially reducing the risk of water shortfall during consecutive dry years. Whereas, the maximum fuzzy release is constrained corresponding to safe channel capacity of tributaries and Upper Mun river, therefore, downstream flooding is accordingly prevented.

Combined effects of precipitation anomalies and dams on streamwater-groundwater interaction in the Fen River basin, China

Both water management measures like damming and changes in precipitation as a result of anthropogenic induced climate change have exerted profound effects on the dynamics of streamwater-groundwater interaction (SGI). However, their compound effects on SGI have not been investigated so far. Taking the Fen River of China as an example, this study aims to examine the synergistic impacts of damming and precipitation anomalies on SGI dynamics. The sampling considered the seasonal and interannual variability of precipitation (May and September in 2019 representing a dry year; May and August in 2021 representing a wet year), and long-term daily observational data, including water levels and water discharge, were combined to elucidate the compound effects. Precipitation anomalies and damming exert significant individual and combined influences on SGI. Separately, dams and reservoirs reversed the SGI dynamics, significantly increasing the contributions of streamwater to groundwater from 0 to 29 % to 78 % in the dam-affected areas. Further, the groundwater discharge ratios behind the dam (about 60 %) were three times higher than those in front of the dam. Precipitation anomalies significantly amplified interannual variability in SGI patterns, and groundwater discharge ratios increased by 47 % during the dry period (2019) compared to flood period (2021). The combined influence of precipitation anomalies and dam regulation remarkably changed the lateral, vertical, and longitudinal water exchange dynamics. Precipitation anomalies affected the SGI dynamics at the whole watershed scale, whereas dam regulation regimes exhibited a stronger control at the local scale. The compound effects of dam regulation and precipitation anomalies can result in different SGI patterns under various climate scenarios. More attention should be paid to the interrelated feedback mechanisms between damming, extreme precipitation events, and their impact on the watershed-scale hydrological cycle.

Can the Integration of Water and Fertilizer Promote the Sustainable Development of Rice Production in China?

Rice production is the agricultural activity with the highest energy consumption and carbon emission intensity. Water and fertilizer management constitutes an important part of energy input for rice production and a key factor affecting greenhouse gas emissions from paddy fields. Water–fertilizer integration management (AIM) is an automated water and fertilizer management system for large-scale rice production, which can effectively save water and fertilizer resources. At present, the energy utilization and environmental impact of AIM in rice production are not clear. To clarify whether AIM is a water and fertilizer management measure that combines energy conservation and carbon emission reduction, a comparative study between the widely used farmers’ enhanced water and fertilizer management (FEM) in China and AIM was conducted in this paper. Field experiments were conducted to evaluate the rice yield, carbon emission, energy utilization, and economic benefits of the two management methods. The results showed that AIM reduced water and fertilizer inputs, energy inputs, and economic costs by 12.18–28.57%, compared to FEM. The energy utilization efficiency, energy profitability, and energy productivity under AIM were improved by 11.30–12.61%. CH4 and N2O emissions and carbon footprint were reduced by 20.79%, 6.51%, and 16.39%, respectively. Compared with FEM, AIM can effectively improve the utilization efficiency of water and fertilizer resources and reduce carbon emissions. This study presents a mechanized water and fertilizer management approach suitable for large-scale rice production systems in China. By analyzing rice yield, resource utilization efficiency, and environmental benefits, AIM can serve as a crucial management strategy for enhancing productivity, economic returns, and environmental conservation within profitable rice production systems. In the future, further investigation into the impact of AIM on the microbial mechanisms underlying rice yield formation and greenhouse gas emissions is warranted.

Reducing greenhouse gas emissions from rice cultivation applied with melaleuca and rice husk biochar in the Vietnamese Mekong Delta

ABSTRACT Biochar application is considered a potential approach to mitigating greenhouse gas emissions (GHGs) from the agricultural sector and improving soil physicochemical properties. Thus, we conducted a field experiment to examine the efficacy of biochar application rates in combination with water management practices on soil methane (CH4) and nitrous oxide (N2O) emissions and carbon increment in the Vietnamese Mekong Delta (VMD). Rice husk biochar (RB) and Melaleuca biochar (MB) were incorporated in the topsoil (0–20 cm) at 5 and 10 Mg ha−1, followed by the water management regimes of continuous flooding (CF) and an alternative wetting and drying (AWD). The results identified that biochar application rates and water management measures were major factors in decreasing CH4 and N2O emissions. Compared with the conventional practice, the RB and MB amendment in the rice fields under CF practices reduced 12.9–21.3% of total GHGs (tGHGs), while biochar incorporation under the AWD management practice reduced from 22.3% to 30.5% tGHGs. Compared to CF treatments, biochar amendment concerning the AWD regime lowered from 25.4% to 31.6% tGHGs. Increasing biochar from 5 to 10 Mg ha−1 did not reduce tGHGs considerably. We identified that biochar application significantly increased grain yields from 12.8% to 20.6% under the CF management practice, while the percentage varied from 2.5% to 3.8% for the AWD practice. Similarly, higher grain yields were achieved from 4.9% to 13.7% by applying AWD compared to the CF treatments. Our findings showed that although higher biochar application rates could reduce the tGHGs, the difference in biochar types and water management applications in connection with the tGHGs was neglectable. Incorporating biochar enhanced soil bulk density and porosity under AWD and CF practices. Going forward in further studies, we recommend a long-term biochar application in the VMD’s low-lying paddy fields with a broader range of biochar rates under different soil types.

Inclusive Management of Our Water Commons

In the past 75 years, since Independence, the central and state governments in India have implemented various measures for water management, which include initiatives to construct and revive small water bodies and wetlands. Schemes such as Amrit Sarovar, Amrit Dharohar, Jalyukta Shivar, and Galmukta Dharan-Galyukt Shivar are being implemented to revive small water bodies. However, these schemes have been criticised for their unsystematic planning and implementation and for benefiting an elite section of society while excluding people experiencing poverty. India is known for its traditional water harvesting systems and community-based management of water commons. Through a case study of grassroots-level management of small-scale waterbodies in eastern Maharashtra, this paper demonstrates the need to understand local dynamics and ground realities for inclusive and efficient water management.

Quantifying the Impact of Human Activities on Hydrological Drought and Drought Propagation in China Using the PCR‐GLOBWB v2.0 Model

AbstractThe economic and human losses caused by drought are increasing, driven by climate change, human activities, and increased exposure of livelihood activities in water‐dependent sectors. Mitigation of these impacts for socio‐ecological securit is necessary to gain a better understanding of how human activities contribute to the propagation of drought as water management further develops. The previous studies investigated the impact of human activities on a macro level, but they overlooked the specific effects caused by human water management measures. In addition, most studies focus on the propagation time (PT, the number of months from meteorological drought propagation to hydrological drought), while other drought propagation characteristics, such as duration, magnitude, and recovery time, are not yet sufficiently understood. To tackle these issues, the PCR‐GLOBWB v2.0 hydrological model simulated hydrological processes in China under natural and human‐influenced scenarios. The study assessed how human activities impact hydrological drought and its propagation. Result shows that human activities have exacerbated hydrological drought in northern China, while it is mitigated in the south. The propagation rate (PR, proportion of meteorological drought propagation to hydrological drought) ranges from 45% to 75%, and the PT is 6–23 months. The PR does not differ substantially between the north and south, while the PT is longer in the north. The PR decreases by 1%–60% due to human activities, and the PT decreases (1–13 months) in the north and increases (1–10 months) in the south. Human activities display significant variations in how they influence the propagation process of drought across different basins. The primary factors driving the spatial pattern of drought disparities are regional variations in irrigation methods and the storage capacity of reservoirs.

Evaluation of the Impacts of Climate Change on Sunflower with Aquacrop Model

Climate change has become one of the most significant risk factors in agricultural production. Plant productivity declines caused by climate change pose a serious threat to food supply and security. Crop simulation models have been widely used in recent years for the assessment of the impacts of climate change on agricultural production. In Konya, there have been limited studies on the potential effects of climate change on sunflower production. Sunflower, the main crop of the most imported agricultural product group, in which the production amount is currently insufficient to cover domestic consumption demand, is strategically important for the Turkish economy. The goal of this study was to examine the effects of climate change on sunflower yield in Türkiye by using the Aquacrop model. The data of the field experiment carried out on the Ekllor sunflower cultivar for two years in Konya conditions were used as material. The daily projection dataset of three Global Climate Models (HadGEM2-ES, MPI-ESM-MR, GFDL-ESM2M) and two scenarios (RCP4.5 and RCP8.5) were used to analyze climate change impacts. The 1971-2000 period was considered as the reference period and the 2022-2098 period was selected as the future period. The results confirmed that the Aquacrop model was able to satisfactorily simulate yield with NRMSE 2.10 % for the rainfed condition and 10.55 % for the irrigated condition, a d-index of 0.97, and a modeling efficiency of 0.91. Aqaucrop climate change impacts simulation which was based on 3 global climate models covering with 2022 -2098 period simulations projected that sunflower yield would be decreased in a range of 21% to 44% for RCP4.5 and 18% to 50% for RCP8.5 scenarios under rainfed conditions. In contrast, the yield would be increased in a range of 11% to 23% for RCP4.5 and 10% to 33% for RCP8.5 scenarios under irrigated conditions. The findings point to the use of appropriate water management measures for future sunflower production as a means of adapting to climate change.

THE HARVESTED RAINWATER AS A SOURCE OF NON-DRINKING WATER SUPPLY IN TYPICAL RESIDENTIAL MICRODISTRICTS OF UKRAINIAN CITIES

Ukraine, facing water resource scarcity, finds it increasingly challenging to provide high-quality drinking water for both its population and industries, particularly in times of war. Harvested rainwater, among these sources, aligns well with water resource protection and management measures to counteract drinking water shortages. A literature review indicates that domestic needs in cities (flushing toilets, cleaning, and laundry) account for over 50% of drinking water demand, which could be supplemented by harvested rainwater. The estimated volume of harvested rainwater for a residential building in Odesa and Uzhgorod showed a drinking water saving to 15% and 36.5%, respectively. Similar calculations were carried out for residential microdistricts with high-rise buildings in these cities, showing a saving of drinking water due to the use of rainwater to 9% and 19%, respectively.

Сырдария өзенінде орналасқан Сарышығанақ бөгетінің су шаруашылығы қызметін оқыту әдістемесі

The scientific work considers one of the alternative options for the development of the ecologically unstable Aral Sea region within the framework of the project for the preservation of the small island and the regulation of the Syrdarya riverbed, which provides for a comprehensive acceleration of water management measures on the Small Island and in the lower reaches of the Syrdarya River to stabilize the ecological situation in the region.

Predicting runoff and sediment yields using soil and water assessment tool (SWAT) model in the Jemma Subbasin of Upper Blue Nile, Central Ethiopia

The Jemma Subbasin (JS) has a major soil erosion problem emanating from deforestation, overgrazing, and agricultural expansion, including farming of unproductive fringed lands and steep slope terrains. This study was conducted to assess runoff and estimate the subsequent sediment yields in the JS using the Soil and Water Assessment Tool (SWAT) model. The overall efficiency of the SWAT model to accurately estimate the sediment yields in the JS was evaluated by the values of its calibration (R2 = 0.66) and validation (R2 = 0.63), respectively. The findings of the SWAT model revealed that barren land was not only the most susceptible land use type to soil erosion, but also had the highest sediment loads followed by agricultural and grazing lands. In particular, the highest soil erosion coupled with significant sediment yields is attributed to the crop-growing period particularly in the months of July and August in which the cultivated lands were extremely vulnerable to soil erosion resulting from heavy rainfall. Consequently, sediment yields were all significantly greater in the agricultural fields of the lower, middle, and upper parts of the subbasin. This is because those agricultural lands were mainly composed of undulated and moderately steep slope terrains so that they had the highest soil erosion values. However, due to the dense vegetation cover and the associated root density, forestlands were the least erosion vulnerable land use type which in turn resulted in minimal soil loss. Furthermore, the SWAT model showed that the maximum upland sediment yield was estimated to be 3,685.14 tons/ha whereas the average upland annual sediment yield was predicted to be 78.1 tons/ha; however, the sediment yield can be doubled due to climate projection scenario. As a result of the effective implementation of cover (c) and conservation practice (p), the SWAT model predicted that the sediment yields can be reduced by 44.28 % and 35.92 % for RCP8.5 and RCP4.5, respectively. Effective designing and executing of proper soil and water management measures are crucial in the study subbasin so as to minimize the serious soil erosion challenges that can be accelerated by climate and land use land cover (LULC) changes for the long-term sustainability of the degraded landscape of the JS which is categorized by subsistence farming.

Response of soil moisture and vegetation growth to precipitation under different land uses in the Northern Loess Plateau, China

The land-use change affects soil hydrological processes in semi-arid areas. Investigating the impact of precipitation change on soil moisture in different land use types (LUTs) is conducive to water resource management and ecological restoration. The volumetric water content (VWC) at 0–300 cm soil profile, meteorology data, and vegetation aboveground biomass were continuously observed from 2018 to 2022 in five terraced and three sloped LUTs. The results showed that soil moisture was affected by precipitation, vegetation, antecedent soil water, soil properties, and artificial management measures. There were significant differences in soil moisture among these land use types (P < 0.05), with the priority order of multi-year profile average VWC at 0–300 cm depth was farmland in the slope (FAS) (0.22 ± 0.01 cm3 cm−3) > bare land in the terrace (BAT) and farmland in the terrace (FAT) (0.19 ± 0.01 cm3 cm−3) > abandoned land in the slope (ABS) (0.18 ± 0.02 cm3 cm−3) > abandoned land in the terrace (ABT) (0.13 ± 0.02 cm3 cm−3) > forage land in the slope (FOS) (0.12 ± 0.02 cm3 cm−3) > forage land in the terrace (FOT) and shrubland in the terrace (SHT) (0.10 ± 0.01 cm3 cm−3). Except for BAT, soil water storage (SWS) in other LUTs decreased in 0–300 cm soil profile from 2018 to 2022. There were no or slight soil desiccations in FAS, BAT, ABS, and FAT, moderate soil desiccation in ABT, and serious soil desiccation in FOS, FOT, and SHT. The VWC, SWS, and soil desiccation index (SDI) of all LUTs were positively correlated with precipitation, especially at 0–100 cm depth. Precipitation threshold response to soil desiccation alleviation was determined to be 98–116 mm month−1. Moreover, aboveground biomass of FOT, ABT, and SHT exhibited a significant correlation with both soil moisture and precipitation (P < 0.05). Therefore, forage lands and shrublands have adverse effects on the mitigation of deep soil desiccation with decreasing rainfall. This study recommended farmland in the terrace and abandoned land in the slope for soil and water conservation and sustainable ecological restoration.