Regional Water Research Articles

Uneven consequences of global climate mitigation pathways on regional water quality in the 21st century

Future socioeconomic climate pathways have regional water-quality consequences whose severity and equity have not yet been fully understood across geographic and economic spectra. We use a process-based, terrestrial-freshwater ecosystem model to project 21st-century river nitrogen loads under these pathways. We find that fertilizer usage is the primary determinant of future river nitrogen loads, changing precipitation and warming have limited impacts, and CO2 fertilization-induced vegetation growth enhancement leads to modest load reductions. Fertilizer applications to produce bioenergy in climate mitigation scenarios cause larger load increases than in the highest emission scenario. Loads generally increase in low-income regions, yet remain stable or decrease in high-income regions where agricultural advances, low food and feed production and waste, and/or well-enforced air pollution policies balance biofuel-associated fertilizer burdens. Consideration of biofuel production options with low fertilizer demand and rapid transfer of agricultural advances from high- to low-income regions may help avoid inequitable water-quality outcomes from climate mitigation.

A multicenter genomic epidemiological investigation in Brazil, Chile, and Mexico reveals the diversity and persistence of Salmonella populations in surface waters.

This study examined the diversity and persistence of Salmonella in the surface waters of agricultural regions of Brazil, Chile, and Mexico. Research groups (three in 2019-2020 and five in 2021-2022) conducted a long-term survey of surface water across 5-8 months annually (n = 30 monthly). On-site, each team filtered 10-L water samples with modified Moore Swabs to capture Salmonella, which were then isolated and identified using conventional microbiological techniques. Salmonella isolates were sequenced on Illumina platforms. Salmonella was present in 1,493/3,291 water samples (45.8%), with varying isolation rates across countries and years. Newport, Infantis, and Typhimurium were the most frequent among the 128 different serovars. Notably, 22 serovars were found in all three countries, representing almost half of the 1,911 different isolates collected. The resistome comprised 72 antimicrobial resistance (AMR) genes and six point mutations in three genes. At least one AMR determinant was observed in 33.8% (646/1,911) of the isolates, of which 47.4% (306/646) were potentially multidrug resistant. Phylogeny based on core genome multilocus sequence typing (cgMLST) showed that most isolates clustered according to sequence type and country of origin. Only 14 cgMLST multi-country clusters were detected among the 275 clusters. However, further analysis confirmed that close genetic relatedness occurred mostly among isolates from the same country, with three exceptions. Interestingly, isolates closely related phylogenetically were recovered over multiple years within the same country, indicating the persistence of certain Salmonella in those areas. In conclusion, surface waters in these regions are consistently contaminated with diverse Salmonella, including strains that persist over time.IMPORTANCESalmonella is a leading foodborne pathogen responsible for millions of illnesses, hospitalizations, and deaths annually. Although Salmonella-contaminated water has now been recognized as an important contamination source in the agrifood chain, there is a lack of knowledge on the global occurrence and diversity of Salmonella in surface water. Moreover, there has been insufficient research on Salmonella in surface waters from Latin American countries that are major producers and exporters of agricultural products. Incorporating genetic profiling of Salmonella isolates from underrepresented regions, such as Latin America, enhances our understanding of the pathogen's ecology, evolution, antimicrobial resistance, and pathogenicity. Moreover, leveraging genomic data derived from pathogens isolated from diverse geographical areas is critical for assessing the potential public health risk posed by the pathogen and expediting investigations of foodborne outbreaks. Ultimately, global efforts contribute significantly to reducing the incidence of foodborne infections.

Water quality indices for the evaluation of the groundwater quality in southwestern Libya

ABSTRACT An investigation was undertaken to consider the quality of the groundwater. The samples were collected from the Southwestern Libya. Forty-one water samples (41) were analyzed for hydrochemical characteristics and suitability for drinking purposes. The parameters for water quality, including calcium, magnesium, sodium, potassium, chloride and bicarbonate, sulfate, nitrate, pH and total dissolved solids (TDS), were examined. The most common worldwide used standard (ST-WQI) and the weighted arithmetic (WA-WQI) water quality indices were selected. The majority of the samples (87.5% wells) described the quality of groundwater in the Alshatti area as excellent to moderate and in the Ghat region (three wells) water quality ranges from excellent to good and is appropriate for direct consumption. In the Wadi al-Ajal areas, 62.5% (10 wells) of samples described the groundwater quality as excellent to good and the rest of the others were poor or unsuitable water. In contrast, most of the obtained results from the Sabha and Ghadduwah areas showed poor to unsuitable water quality for drinking use. Furthermore, samples are higher with pH and alkalinity values. The alkalinity does not pose a health risk but can cause esthetic problems. Generally, most of the areas’ water quality indices for physicochemical parameters indicated suitability for drinking purposes.

Geochemical characterization of spring waters from the Tinerkouk region, southwestern Algeria

ABSTRACT The present work focused on the geochemical characterization of spring water in the Tinerkouk region in southwestern Algeria. The suitability of the spring water for drinking was assessed using its physicochemical parameters, which included pH, total dissolved solids, major and minor cation and anion compositions, and electrical conductivity. These parameters were compared to Algerian regulations and WHO (World Health Organization) standards to see if the water met the requirements for both spring water and mineral water according to the prevailing standards in force. For this purpose, 43 spring water samples were collected from Tinerkouk region and especially from mineral water unit of Tazliza, during the period 2009-2022. The results obtained for pH, conductivity, sulfate, chloride, nitrate, sodium, and potassium, showed that the water samples from all the sampled springs were acceptable for consumption and within the acceptable limits in accordance with specified criteria, except for Oudghagh, Fatis, and Benzita. However, at these sites, TDS, conductivity, nitrates, and chlorides exceeded the acceptable values. It was also noted that, the spring water from the Tazliza unit is classified as excellent for drinking purposes and meets the permissible limits defined by the legislation for mineral and spring waters. The results also indicate that the predominant chemical facies of the Tazliza spring waters are chlorinated and sulfated sodium and potassium.

Paleoenvironment and vegetational history of a Middle Pennsylvanian intramontane peat swamp: an example from the Lower Radnice Coal, Kladno coalfield (Czech Republic)

AbstractThe depositional environment, hydrology and vegetational history of the Lower Radnice Coal (Duckmantian) in the Kladno coalfield was studied using sedimentary geology, coal petrology and paleobotanical/palynological methods. The peat accumulating wetland of the coal formed in a fluvial paleovalley approximately 15 km long and 2–5 km wide, bordered by basement paleohighs and landlocked in the interior of the central European Variscides. The peat swamp evolved on top of mud-dominated floodplain successions pedogenically modified to a vertic gleyed Protosol. Probably climatically controlled rising ground water table resulted in paludification that from downstream part gradually spread upstream. Most clastic load was deposited in the upper part of the valley, whereas only mud suspension was dispersed downstream throughout the vegetated swamp. The best conditions for peat accumulation were situated in the eastern part of the paleovalley, where up to 1.5 m thick coal with thin bands of impure coal and carbonaceous mudstone formed in an occasionally inundated rheotrophic system with peat accretion controlled by regional ground water table. The peat swamp was vegetated mainly by lepidodendrid lycopsids with Lepidodendron and Paralycopodites being dominant genera. Shrubby to ground cover vegetation was represented by medulosallean pteridosperms, small shrubby lycopsids, sphenopsids, and herbaceous ferns. Tree ferns were locally abundant, especially in mineral-rich substrates. The rheotrophic character of the peat swamp may indicate higher seasonality of the Variscan interior, compared to coastal areas in the North Variscan foreland with contemporaneous ombrotrophic peats. Modern equivalents of the Lower Radnice Coal swamp are inland planar tropical peat swamps in tributary paleovalleys of the Tasek Bera in peninsular Malaysia and central Congo basins. Graphical abstract Lower Radnice Coal peat swamp.

Human Activities Have Altered Sediment Transport in the Yihe River, the Longest River Originating from Shandong Province, China

Climate change and human activities affect regional sediment transport and ecological environment construction. Investigating sediment transport and its influencing factors in the Yihe River Basin (YHRB) will provide guidance for regional soil and water conservation and sustainable development. We analyzed the chronological changes, cycles, spatial distribution and influencing factors using Mann–Kendall (M-K) trend analysis, wavelet analysis, and the Pettitt mutation point (PMP) test, then quantified the role of precipitation and human activities in sediment transport changes. The results showed that annual precipitation decreased marginally, whereas sediment load has noticeably declined. Four precipitation cycles were observed: 4–8a, 9–14a, 16–19a, and 20–28a, where 9–14a was dominant; sediment transport cycles were tracked: 3–5a, 9–15a, and 30a, where 30a was dominant with a decreasing trend. The sediment load was higher in the central, northern, and southwestern sub-basins of the YHRB, while it was lower in the southeast. The contribution of human activities and precipitation changes to sediment transport was 73.14% and 26.86% in transitional phase I (1965–1980) and 71.97% and 28.03% in transitional phase II (1981–2020), respectively. Hydraulic engineering construction, water resource development, land-use changes, and soil and water conservation measures intercepted precipitation and sediment, making them the primary factor affecting sediment transport changes in the YHRB.

Impact of Asian aerosols on the summer monsoon strongly modulated by regional precipitation biases

Abstract. Reliable attribution of Asian summer monsoon variations to aerosol forcing is critical to reducing uncertainties in future projections of regional water availability, which is of utmost importance for risk management and adaptation planning in this densely populated region. Yet, simulating the monsoon remains a challenge for climate models that suffer from long-standing biases, undermining their reliability in attributing anthropogenically forced changes. We analyze a suite of climate model experiments to identify a link between model biases and monsoon responses to Asian aerosols and associated physical mechanisms, including the role of large-scale circulation changes. The aerosol impact on monsoon precipitation and circulation is strongly influenced by a model's ability to simulate the spatio-temporal variability in the climatological monsoon winds, clouds, and precipitation across Asia, which modulates the magnitude and efficacy of aerosol–cloud–precipitation interactions, an important component of the total aerosol response. There is a strong interplay between South Asia and East Asia monsoon precipitation biases and their relative predominance in driving the overall monsoon response. We found a striking contrast between the early- and late-summer aerosol-driven changes ascribable to opposite signs and seasonal evolution of the biases in the two regions. A realistic simulation of the evolution of the large-scale atmospheric circulation is crucial to realize the full extent of the aerosol impact over Asia. These findings provide important implications for better understanding and constraining the diversity and inconsistencies of model responses to aerosol changes over Asia in historical simulations and future projections.

Diagnosis of the physicochemical quality of groundwater in the Zaouiet Kounta Region

The water resources of the Adrar region are essentially represented by the water table, which supplies all the oases with water through ancient techniques called “foggaras.” This study aims to determine the state of the quality of the waters of the Adrar region, essentially based on the water’sphysicochemical parameters assessment, which allows us to have an idea of its quality and availability for drinking water supply and irrigation. Thirteen parameters were analyzed: pH, conductivity, turbidity, pollution elements such as nitrates, nitrites, ammonium, phosphates, and organic matter, and mineralization elements: calcium, magnesium, sodium, chlorides, and sulfates.The physicochemical characterizations of the waters of this region will be based on the interpretation of different parameters of the data during a campaign of sampling and analysis of samples and comparing them with the WHO.The results showed that the measurements of the physicochemical parameters of the waters analyzed conformedwith the WHO, such as pH, turbidity, ammonium, and phosphate. At the same time, sulfate, sodium, Chloride, and nitrate presented high values. It proved abnormal in the three points of foggara, while the rest of the analyses showed values varying between F1, F2, and F3.

Ebullition dominates methane emissions in stratified coastal waters

Coastal areas are an important source of methane (CH4). However, the exact origins of CH4 in the surface waters of coastal regions, which in turn drive sea-air emissions, remain uncertain. To gain a comprehensive understanding of the current and future climate change feedbacks, it is crucial to identify these CH4 sources and processes that regulate its formation and oxidation. This study investigated coastal CH4 dynamics by comparing water column data from six stations located in the brackish Tvärminne Archipelago, Baltic Sea. The sediment biogeochemistry and microbiology were further investigated at two stations (i.e., nearshore and offshore). These stations differed in terms of stratification, bottom water redox conditions, and organic matter loading. At the nearshore station, CH4 diffusion from the sediment into the water column was negligible, because nearly all CH4 was oxidized within the upper sediment column before reaching the sediment surface. On the other hand, at the offshore station, there was significant benthic diffusion of CH4, albeit the majority underwent oxidation before reaching the sediment-water interface, due to shoaling of the sulfate methane transition zone (SMTZ). The potential contribution of CH4 production in the water column was evaluated and was found to be negligible. After examining the isotopic signatures of δ13C-CH4 across the sediment and water column, it became apparent that the surface water δ13C-CH4 values observed in areas with thermal stratification could not be explained by diffusion, advective fluxes, nor production in the water column. In fact, these values bore a remarkable resemblance to those detected below the SMTZ. This supports the hypothesis that the source of CH4 in surface waters is more likely to originate from ebullition than diffusion in stratified brackish coastal systems.

Прогнозирование углеводородоперспективных структур кольцевого вида в Баренцевоморском регионе по результатам применения стохастического метода при использовании совокупности геопараметров

The article presents the results of the application of the stochastic method used to predict hydrocarbon-prospective geostructures of a concentric type within the Barents Sea region. According to thecalculated values ofstochastic parameters for the 21 geostructures of aconcentric view in the waters of the Barents region, based on four different geoparameters a summary table of stochastic parameters was compiled and an encouraging forecast was made for 13 concentric geostructures promising for the search for new oil deposits within the Barents Sea region.

Hydrochemical characterization of a Dinaric karst catchment in relation to emerging organic contaminants

The main findings of a hydrochemical investigation conducted within a typical Dinaric karst catchment located in Southern Croatia are outlined. The studied aquifer is drained by the Jadro and Žrnovnica springs, which are important for the regional and local water supplies, respectively. Presumably, there is intercatchment groundwater flow coming from the neighbouring Cetina River catchment. Various factors governing aquifer hydrochemistry and their interplay with emerging organic contaminants (EOCs) that were detected at different water resources in ng/L concentrations was assessed. A total of 26 sampling campaigns (October 2019 – October 2022) were conducted at two springs, in a river and at a deep borehole, all representative of this complex hydrogeological system. Assessment of major ion constituents and saturation indices calculated with PHREEQC revealed the sampled water resources are of a Ca-HCO3 type due to the predominant weathering of the carbonate mineral calcite. Sharp spikes observed in chemographs indicated a highly karstified system with an effective conduit network allowing rapid spring responses to precipitation events. Water resources are of good chemical status, as affirmed by anthropogenic contamination indicators, with nitrates, chlorides and sulphates all below maximum threshold values. Strong positive correlations were found between EOCs concentration, number of detected compounds, and nitrates in the Cetina River, indicating a common origin, most likely wastewater. Identification of persistent EOCs including widely used repellent N,N-diethyl- metatoluamide (DEET) during base flow conditions and its strong positive correlation with the Ca2+ content in both the Cetina and Jadro samples, suggests potential storage in the epikarst and aquifer matrix. This coupling of conventional hydrochemical indicators and novel markers of anthropogenic impacts, including EOCs, in vulnerable karst water resources is a crucial advancement in the assessment and management of emerging environmental and potential human health risks. Such an approach is pivotal for the sustainable protection of hydrogeologically intricate sites.

Appraising water resources for irrigation and spatial analysis based on fuzzy logic model in the tribal-prone areas of Bangladesh.

The lack of quality water resources for irrigation is one of the main threats for sustainable farming. This pioneering study focused on finding the best area for farming by looking at irrigation water quality and analyzing its location using a fuzzy logic model on a Geographic Information System platform. In the tribal-prone areas of Khagrachhari Sadar Upazila, Bangladesh, 28 surface water and 39 groundwater samples were taken from shallow tube wells, rivers, canals, ponds, lakes, and waterfalls. The samples were then analyzed for irrigation water quality parameters like electrical conductivity (EC), total dissolved solids (TDS), sodium adsorption ratio (SAR), soluble sodium percentage (SSP), residual sodium bicarbonate (RSBC), magnesium hazard ratio (MHR), Kelley's ratio (KR), and permeability index (PI). Fuzzy Irrigation Water Quality Index (FIWQI) was employed to determine the irrigation suitability of water resources. Spatial maps for parameters like EC, KR, MH, Na%, PI, SAR, and RSBC were developed using fuzzy membership values for groundwater and surface water. The FIWQI results indicate that 100% of the groundwater and 75% of the surface water samples range in the categories of excellent to good for irrigation uses. A new irrigation suitability map constructed by overlaying all parameters showed that surface water (75%) and some groundwater (100%) in the northern and southwestern portions are fit for agriculture. The western and central parts are unfit for irrigation due to higher bicarbonate and magnesium contents. The Piper and Gibbs diagram also indicated that the water in the study area is magnesium-bicarbonate type and the primary mechanism of water chemistry is controlled by the weathering of rocks, respectively. This research pinpoints the irrigation spatial pattern for regional water resource practices, identifies novel suitable areas, and improves sustainable agricultural uses in tribal-prone areas.

Rainfall partitioning characteristics and simulation of typical shelter forest in Chinese Mu Us Sandy Land

Numerous shelter forests have been established to combat desertification in the Mu Us Sandy Land, China. Shelter forests modify the characteristics of the underlying surface and affect the regional water cycle by altering rainfall partitioning. Understanding the rainfall partitioning process and its controlling factors for indigenous and exotic species is crucial for vegetation restoration and sustainable soil water management. This study developed an event-based rainfall partitioning process for three typical shelter forests. Indigenous vegetation, Amygdalus pedunculata Pall. (A. pedunculata), and two exotic species, Amorpha fruticosa L. (A. fruticose) and Pinus sylvestris var. mongholica Litv. (P. sylvestris), were observed during the rainy seasons (July and August) of 2021 and 2022. The results showed that throughfall, stemflow, and interception loss constituted 71.01 %, 8.23 %, and 20.76 % of rainfall, respectively, for A. pedunculata. The corresponding values were 74.65 %, 8.47 %, and 16.88 % for A. fruticose and 73.27 %, 1.44 %, and 25.29 % for P. sylvestris. Compared with the introduced P. sylvestris, the shrub canopy showed a greater funneling ratio and was conducive to recharging soil water by precipitation. The amount and intensity of rainfall were significantly correlated with the rainfall partitioning characteristics, whereas the correlation between rainfall duration and partitioning was insignificant. Based on the results of the revised Gash model, the stemflow was primarily influenced by the percentage of rainfall diverted to the stemflow. The interception loss for P. sylvestris was primarily influenced by the canopy storage capacity. However, the canopy storage capacity and the ratio of mean evaporation rate to mean rainfall intensity had significant effects on the interception loss in A. pedunculata and A. fruticose. It is necessary to comprehensively consider the vegetation type (tree/shrub and indigenous/exotic species) and the corresponding rainfall partitioning characteristics of shelter forests for the scientific construction and management of shelter forests in the Mu Us Sandy Land.

Sustainability Assessment and Multi-angle Diagnosis of Regional Water Resources-Social Economy-Ecological Environment System Using a Novel TODIMSort with MS Clustering Algorithm

Sustainability Assessment and Multi-angle Diagnosis of Regional Water Resources-Social Economy-Ecological Environment System Using a Novel TODIMSort with MS Clustering Algorithm

Simulation of flood protection using Hec Ras Modeling: A case study of the Lam Phra Phloeng river basin

The Lam Phra Phloeng reservoir, positioned within the Lam Phra Phloeng river basin and situated in Nakhon Ratchasimi province, assumes a substantial role in the realm of regional water management. During severe storms in the reservoir's upper region, excess water flows downstream, occasionally resulting in devastating floods in Pak Thongchai district, as witnessed in 2010 and 2020. Both flooding events have resulted in significant economic, social, and livelihood disruptions to the local population in the affected areas. This study pursues two primary objectives: firstly, to assess the extent of flood-prone areas across various return periods (2, 5, 10, 25, 50, 100, and 500 years); secondly, to employ Hec Ras modeling for an in-depth analysis of strategies aimed at flood prevention and mitigation within the Lam Phra Phloeng river basin. The Hec Ras modeling incorporates both 1D and 2D flow simulations. The findings reveal that the flood-prone areas, corresponding to the specified return periods, occupy 0.20%, 1.10%, 1.60%, 2.08%, 2.39%, 2.66%, and 3.17% of the total area in the Lam Phra Phloeng river basin, respectively. To safeguard against flooding and minimize its impact, a multifaceted approach is recommended, encompassing the construction of water barrier flaps, augmentation of water transmission and drainage capacity, implementation of flood alarm systems along the Lam Phra Phloeng river, installation of runoff stations, and the establishment of a comprehensive database system for flood and drought prevention. Among these measures, constructing water barrier flaps and enhancing water transmission and drainage capabilities stand out as effective strategies to protect the Lam Phra Phloeng river basin from flooding.

Sensitivity of joint atmospheric-terrestrial water balance simulations to soil representation: Convection-permitting coupled WRF-Hydro simulations for southern Africa

Regional weather and climate models play a crucial role in understanding and representing the regional water cycle, yet the accuracy of soil data significantly affects their reliability. In this study, we employ the fully coupled Weather Research and Forecasting Hydrological Modeling system (WRF-Hydro) to assess how soil hydrophysical properties influence regional land-atmosphere coupling and the water cycle over the southern Africa region. We utilize four widely-used global soil datasets, including default soil data for model from the Food and Agriculture Organization, and alternative datasets from the Harmonized World Soil Database, Global Soil Dataset for Earth System Model, and global gridded soil information system SoilGrids. By conducting convection-permitting coupled WRF-Hydro simulations with the Noah-MP land surface model using each of the aforementioned soil datasets, our benchmark analysis reveals substantial differences in soil hydrophysical properties and their significant impact on the simulated regional water cycle during the austral summer. Alterations in soil datasets lead to both spatial and temporal variations in surface water and energy fluxes, which in turn profoundly influence the atmospheric thermodynamic structure. Reduced soil water-holding capacity leads to subsequent reduction in soil moisture and latent heat, resulting in significant decreases in convective available potential energy and convective inhibition, signaling potential effects on precipitation distributions. In arid interior regions of southern Africa, shifts towards drier and warmer surface conditions due to soil data discrepancies are found to enhance atmospheric moisture convergence, suggesting a possible localized negative feedback of soil moisture on precipitation. Overall, the results for southern Africa indicate that soil data discrepancies exert more pronounced impact on terrestrial fields in dry subregions and on atmospheric fields in temperate subregions, highlighting the broad uncertainties in the regional water cycle reproduced within the model.

Evaluation of water resources carrying capacity in China based on entropy weight TOPSIS model

Water resources carrying capacity refers to the ability of the water resources ecosystem to continuously carry the coordination relationship between human society and economy in the normal development process of a country or a region. Its self-sustaining ability, self-regulation and self-development potential often hinder sustainable development in water shortage areas. Research on water resources’ carrying capacity is a meaningful way to support regional water resources security and realize harmonious development of society, economy, and ecological environment. Correct assessment of water carrying capacity and response to government policies will contribute to improved water use and sustainable economic and social development. This study first sorts out the relevant questionnaires of water resources carrying capacity level evaluation, proposes the evaluation indicators of water resources carrying capacity level, collects and standardizes the required data, and calculates the weight of each evaluation index by entropy weight method. Then, it calculates the comprehensive evaluation value of China’s water resources carrying capacity from 2012 to 2022 in the TOPSIS model. The results show that the total afforestation area, total investment in environmental pollution control, and total industrial wastewater discharge are the third most important factors in improving the carrying capacity of water resources. From 2003 to 2010, China’s water resources carrying capacity improved year by year. From 2011 to 2021, China’s water resources carrying capacity remained stable year by year. The continuous adjustment of China’s industrial structure and strengthening environmental pollution control are inevitable measures to improve the carrying capacity of China’s water resources. This study provides a scientific basis for exploring the changing trend of China’s water resources carrying capacity and formulating reasonable optimal allocation of water resources. It also has great significance for promoting China’s water resources’ carrying capacity and sustainable development of the social economy and ecological environment.

Optimizing food crop layout considering precipitation uncertainty: Balancing regional water, carbon, and economic pressures with food security

As the global food supply chain becomes increasingly unstable, food security is gaining importance in China. Nevertheless, factors such as water scarcity, limited land resources, and global climate change pose great challenges to increasing food production. Therefore, it is crucial to explore sustainable development models for food systems. In this paper, a multi-objective crop layout model considering crop rotation is constructed and solved using the INSGA2-DS algorithm. Various precipitation scenarios were established for climate change. Data analysis and optimization were conducted under different precipitation scenarios. Applied in the plain area of southwestern Shandong Province, the model can increase soybean yield by 6.78%, net carbon sequestration intensity by 0.04%, net benefit by 2.09%, and crop water productivity by 3.91% during a median flow year. Optimization tends to increase the total area planted with food crops during wet years and decrease it during dry years. The optimization model can enhance water productivity and carbon sequestration intensity of crops, as well as prevent unreasonable fluctuations in the area planted with food crops. This enables the benefits of water conservation and yield increase to be fully utilized, and reduces yield and economic losses due to dry years. The models help to rationally allocate soil and water resources, effectively respond to climate change risks, and provide robust decision support for regional food crop planning.

Optimal Allocation of Water Resources in Ordos City Based on the General Water Allocation and Simulation Model

This study aims to achieve coordination between regional economic development and ecological environmental protection and to mitigate issues such as competition for water use among industries and significant disparities between water supply and demand. A multi-water-source, multi-user, and multi-objective optimal water resource allocation model was developed for Ordos City using general water allocation and simulation (GWAS). This model was applied to optimize water resource allocation on a monthly scale for various users across different administrative units (banners) in both short- and long-term planning periods. The results indicate that Ordos City’s allocated water volume for 2025 and 2030 is projected to be 1833.36 × 106 m3 and 1963.44 × 106 m3, respectively, with an overall water shortage rate of 5.46% and 5.67%, respectively. Water shortages are predicted in Dongsheng District, Dalad Banner, Etuoke Banner, Hangjin Banner, and Wushen Banner, primarily during the agricultural water usage period from March to November. The regional water supply structure was notably optimized, with a gradual decrease in the proportion of groundwater in the total water supply and a corresponding increase in the supply of surface water and unconventional water. These changes effectively improve local groundwater overexploitation and enhance the water supply efficiency. The research findings could offer valuable theoretical and technical support for the development and utilization of water resources, as well as for adjustments in the population–economic–industrial structure of Ordos City. Additionally, this study could provide scientific references for optimizing water resource allocation in other water-deficient cities in arid and semi-arid areas of the Yellow River Basin.

Assessing the impact of climate and crop diversity on regional greenhouse gas emissions and water demand of cropland

To tackle the challenges of climate warming and freshwater scarcity, evaluating greenhouse gas (GHG) emissions and water demand in agricultural production can contribute positively to sustainable agricultural practices. This study aims to quantify the GHG emissions and water requirements of three major grains in diverse environmental regions in China, with a specific focus on exploring their spatial heterogeneity due to regional differences. The parameterized DNDC model was used to quantify crop GHG emissions, while the Penman-Monteith equation was utilized to assess crop water demand. The result showed that the total GHG emission of major grain in China was 372.43 Tg/yr (CO2), 11.68 Tg/yr (CH4), 475.56 Gg/yr (N2O) respectively; and the water demand was 473.60 Gm3, in 2015. The Middle-lower Yangtze Plain (MLYP) had the highest emission and water demand. High-temperature and high-precipitation regions had greater GHG emission intensity; the intensity of different GHG emissions was significantly influenced by the type of crops. Late rice had the highest emission intensity. The geospatial distribution of GHG emissions and water demand displayed opposite patterns, with meteorological conditions and crop types as the main reasons. Soil bulk density was the most significant soil element influencing regional emissions. These results will help to assess the spatial heterogeneity of agricultural “water and carbon”, and the quantitative results can be used as evaluation indicators to establish resource- and environment- friendly agricultural cropping patterns suitable for different cropping regions.