Utilization Of Regional Water Resources Research Articles

Study on the Evolvement Trend Process of Hydrological Elements in Luanhe River Basin, China

Over the past 50 years, there have been significant changes in the runoff process in the Luanhe River basin, exacerbating the scarcity of water resources and their spatiotemporal variability. Therefore, conducting research on the characteristics, trends, and cycles of runoff changes in the Luanhe River basin is of great theoretical and practical significance. This study selected rainfall data from the hydrological stations in Weichang, Chengde, and Qinhuangdao in the Luanhe River basin, covering the period from 1985 to 2008, as well as runoff data from the Hanjiaying, Sandaohezi, and Chengde stations. Based on linear trend regression analysis, the Mann–Kendall rank correlation test, Spearman correlation test, Mann–Kendall method, and Mann–Whitney–Pettitt change point analysis method, this study analyzed the trends in water quantity changes and their change points in the Luanhe River basin. The results of the precipitation at the Weichang and Chengde stations show a non-significant rising trend, remaining relatively stable with slightly increases. Conversely, the precipitation of Qinhuangdao Station shows a decreasing trend over time, albeit non-significant. Considering the detailed diagnostic results from both the Mann–Kendall (M-K) and MWP methods, the change point for Weichang precipitation is identified as 2007, while for Chengde, it spans from 1999 to 2002, and for Qinhuangdao, it is around 1997. The trend of the runoff series of three stations shows a significant decreasing trend and strong significance, and the change point for the annual runoff at the Hanjiaying station and the Sandaohezi station is identified as 2006, and for the Chengde station, the primary change point is 2006, with a secondary change point around 2002. The findings of this research can provide scientific references for the rational development and utilization of regional water resources.

Unveiling the Dynamics and Influence of Water Footprints in Arid Areas: A Case Study of Xinjiang, China

A prerequisite for the rational development and utilization of regional water resources is the measurement of water stress. In this study, from the perspective of water footprints, we took the proportion of the agricultural water footprint within the total water resource usage of Xinjiang (hereafter referred to as XJ) as an example to measure its water stress index and explore the state of water stress in the region and its corresponding driving factors. The ESDA method was applied to characterize the spatial patterns of and correlations with water stress. The effects of different factors on the spatial differentiation between the water footprint and water stress were quantified using the LMDI and geoprobes, respectively. The results showed that (1) both the agricultural water footprint and the water stress index in XJ showed an upward trend, the spatial distribution of water stress was uneven, and the regional pressure difference between the east and the west was greater than that between the north and the south; (2) the water stress index has an obvious negative spatial correlation, fluctuations in its discrete nature have been enhanced, and the number of spatially correlated prefectures is decreasing; (3) water consumption of CNY 10,000 GDP, GDP per capita, and total CO2 emissions have the most significant impact on the evolution of the agricultural water footprint in XJ. Meanwhile, spatial variations in water stress are mainly determined by the area of cultivation, the area of natural oasis, and the proportion of water used in agriculture. Analysis of the characteristics of and factors influencing water stress in XJ from the perspective of its agricultural water footprint provides a new perspective for further analyzing the actual state of the water footprint and water stress in XJ and supplies a reference basis for the decision-makers of the XJ government.

Response of blue-green water to climate and vegetation changes in the water source region of China's South-North water Diversion Project

The characteristics of water fluctuations within the basin have remained ambiguous in recent years due to climate and vegetation changes, posing a challenge to the planning and utilization of regional water resources. This study coupled the Priestley-Taylor Jet Propulsion Laboratory (PT-JPL) model, which can consider vegetation dynamics information and evapotranspiration physical mechanisms, into the Distributed Time Variant Gain Model (DTVGM) to improve the hydrological simulation accuracy under changing environments. Based on different simulation scenarios of the coupled model, the effects of climate and vegetation changes on hydrological processes were fully investigated using blue and green water (BW and GW) as assessment metrics. The upper Han River Basin (UHRB), as water source for the Central Line Project of China’s South-North Water Diversion (CSNWD), was selected as a typical basin for the study, results indicated that: (1) The DTVGM coupled with PT-JPL could better reflect the spatiotemporal patterns of major hydrological processes (runoff, evapotranspiration, and soil moisture) in UHRB from 2001 to 2019; (2) The BW in UHRB exhibited decreasing trend from 2001 to 2019, while the GW on the contrary. Surface runoff (Rs), vegetation transpiration (Et), and soil moisture (W) contributed most in the components of BW and GW; (3) Vegetation change dominated by greening in UHRB, which facilitated the transformation of BW to GW in the basin, and it increased the proportion of GW mainly by promoting Et. BW was mainly influenced by precipitation, but vegetation change altered the original correlation between climatic factors and hydrological processes. This study can support the management of water resources in the basin under changing environments.

Divergent glacier area and elevation changes across the Tibetan Plateau in the early 21st century

With accelerated warming, mountain glaciers in most parts of the world have been in a state of continuous retreat in recent decades. Assessing glacier change and analyzing its influencing factors are essential for developing climate change mitigation and adaptation measures for a given region. This study provides a spatially explicit assessment and quantification of glacier changes in the early 21st century on the Tibetan Plateau (TP) at individual glacier and basin scales. We established a one-to-one correspondence between the Second Chinese Glacier Inventory (CGI-2, collected from 2004 to 2011) and a dataset of glacier inventory in Western China during 2017–2018 (CGI-2018). The majority of TP’s glaciers decreased in size with a mean area retreat rate during the investigated period of 4.1%/decade. In addition, a mean change of the median elevation of the glaciers of 6.7 m/decade was detected. Approximately 2.5% of the total number of glaciers mapped in CGI-2 disappeared, while 681 of them divided to 1758 glaciers as they retreated. The observed variations follow local trends and have different regional characteristics. Generally, the glaciers with the lowest retreat rates are found in the Karakorum and Kunlun Mountains, while those with high retreat rates are concentrated along the Gangdis and Tangula ranges. The observed changes in glaciers are mainly attributed to a significant increase in temperature. Other factors including glacier size, debris cover, orientation and mean elevation also contribute to the heterogeneity of glacier variability. This study provides for the first time a detailed spatially explicit analysis of the glacial changes on the TP in the early 21st century, substantially improving the understanding of glacier response patterns and supporting more sustainable utilization of regional water resources in the TP in the context of climate warming in the 21st century.

Spatiotemporal characteristics of evaporation in China and its response to revegetation in a typical region by a generalized complementary approach

The generalized nonlinear advection aridity (GNAA) model has been widely applied for evaporation estimations and drought assessments at regional and global scales. Here, the GNAA model was combined with a semi-empirical function for the parameter αe-B to estimate actual evaporation (E) in nine Level-I water resources regions and one typical revegetation area (i.e., the Loess Plateau) in China. The results showed that the semi-empirical function for αe-B with aridity index rescaled the original independent variable (xB) in GNAA; thus, the model satisfied the boundary condition of “y = 0, at xB-αf =0”. Moreover, the data points of E/Epa (Epa: apparent potential evaporation) and Epo/Epa (Epo: potential evaporation) were captured well by the GNAA curve with the semi-empirical function of αe-B. Further, the GNAA model showed high accuracy in simulating evaporation (ECR-B) when compared with the water balance equation, with the mean absolute error, root mean square error, and Nash-Sutcliffe efficiency values being 52 mm, 66 mm, and 0.84 respectively, over 49 basins. The multi-year mean ECR-B was 443.1 ± 14.7 mm/yr and 431.6 ± 21.2 mm/yr across China and Loess Plateau, respectively. Moreover, the annual ECR-B showed a significant upward trend during 1982–2017, and ECR-B increased rapidly before 1998, but decreased slightly after 1998 when considering 1998 as the turning point across China. Since the implementation of the large scale “Grain for Green” project on the Loess Plateau, nomalized difference vegetation index (NDVI) and precipitation increased significantly, while ECR-B showed no significant increases in both China and Loess Plateau. For the Loess Plateau, annual precipitation increased faster than annual evaporation, implying that water yield may increase. Overall, the findings would assist in clarifying the characteristics of evaporation across China and contribute to better management and sustainable utilization of regional water resources.

Evaluation of Regional Water Ecological Economic System Sustainability Based on Emergy Water Ecological Footprint Theory—Taking the Yellow River Basin as an Example

In the article, on the basis of quantifying the emergy water ecological footprint, a sustainability evaluation system for the overall water ecological economic system of the basin and each province (region) was proposed. And using the subjective and objective combination of the Analytic Hierarchy Process (AHP) and Entropy Weight Method (EWM) to determine the weight of the indicator system, a TOPSIS model for sustainability evaluation was constructed. And taking the Yellow River Basin as an example, the results indicate that (1) Throughout the entire basin, the sustainability of the water ecological economic system showed a fluctuating upward trend year by year during the study period, from 0.37 to 0.51. (2) In each province (region), the sustainability of the water ecological economic system had gathered in space. The overall sustainability level of the upstream Sichuan, Qinghai and Gansu provinces is high, always at level (I). The overall sustainability level of the midstream Ningxia and Neimenggu was low, always at level (IV). The overall sustainability level of the downstream Shaanxi, Shanxi, Henan and Shandong provinces is high, rising gradually over time, from level (III) to level (II) or (I). Against the backdrop of the rapid development of the economy and society, the contradiction between economic and social development, ecological environment protection, and sustainable utilization of water resources is becoming increasingly severe, which has become a key factor restricting the sustainable development of the ecological economic system in Yellow River Basin. Multidimensional comprehensive evaluation of the sustainability level of the regional water ecological economic system is a prerequisite for identifying sustainable development issues in the Yellow River Basin, and also the basis for formulating targeted policies for sustainable utilization of regional water resources and high-quality economic development.

Monthly runoff prediction based on a coupled VMD-SSA-BiLSTM model

The accurate prediction of monthly runoff in the lower reaches of the Yellow River is crucial for the rational utilization of regional water resources, optimal allocation, and flood prevention. This study proposes a VMD-SSA-BiLSTM coupled model for monthly runoff volume prediction, which combines the advantages of Variational Modal Decomposition (VMD) for signal decomposition and preprocessing, Sparrow Search Algorithm (SSA) for BiLSTM model parameter optimization, and Bi-directional Long and Short-Term Memory Neural Network (BiLSTM) for exploiting the bi-directional linkage and advanced characteristics of the runoff process. The proposed model was applied to predict monthly runoff at GaoCun hydrological station in the lower Yellow River. The results demonstrate that the VMD-SSA-BiLSTM model outperforms both the BiLSTM model and the VMD-BiLSTM model in terms of prediction accuracy during both the training and validation periods. The Root-mean-square deviation of VMD-SSA-BiLSTM model is 30.6601, which is 242.5124 and 39.9835 lower compared to the BiLSTM model and the VMD-BiLSTM model respectively; the mean absolute percentage error is 5.6832%, which is 35.5937% and 6.3856% lower compared to the other two models, respectively; the mean absolute error was 19.8992, which decreased by 136.7288 and 25.7274 respectively; the square of the correlation coefficient (R2) is 0.93775, which increases by 0.53059 and 0.14739 respectively; the Nash–Sutcliffe efficiency coefficient was 0.9886, which increased by 0.4994 and 0.1122 respectively. In conclusion, the proposed VMD-SSA-BiLSTM model, utilizing the sparrow search algorithm and bidirectional long and short-term memory neural network, enhances the smoothness of the monthly runoff series and improves the accuracy of point predictions. This model holds promise for the effective prediction of monthly runoff in the lower Yellow River.

Spatiotemporal Evolution Characteristics and Driving Factors of Water Conservation Service in Jiangxi Province from 2001 to 2020

Water conservation services are key indicators of ecological services. Against the backdrop of frequent extreme weather events and water scarcity caused by global climate change and intensified human activities, assessing these services and their drivers are crucial tasks for regional ecological security and sustainable development. Jiangxi Province is one of the first national ecological civilization pilot zones in China, representing an important ecological barrier in southern China. Exploring the characteristics of spatial and temporal changes in water conservation and their driving factors can facilitate the rational development and utilization of regional water resources and the construction of ecological civilizations. Therefore, based on long time series data, the InVEST model was used to explore the spatiotemporal evolution characteristics of water conservation services, and to elucidate the trend of their change through the Theil–Sen median trend analysis and the Mann–Kendall test; then, the geographic detector and geographically weighted regression model were used to further analyze the drivers of spatial variability of water conservation services. The results showed the following: (1) The average depth of water conservation was 103.18 mm, showing a spatial pattern of “low in the middle, high in the surroundings, high in the north and low in the south”. (2) Slight improvements were primarily observed (77.49%), with only 1.60% of the area showing significant improvements. (3) Land use was the main driver of the spatial differentiation, and the interaction between precipitation and forestland had a significantly greater effect on spatial heterogeneity than any single factor. (4) Obvious spatial heterogeneity occurred in the driving factor impacts, with natural factors (precipitation, evapotranspiration, forestland, and grassland) having a positive impact on water conservation services, and land-use factors (construction land and cropland) and socioeconomic factors (population density and land area) having a negative effect. This study provides a reference for water-conservation-based ecosystem construction and policy formulation in Jiangxi Province.

Quantitative analysis of regional water resources and secure development of economic and social coupling systems

Abstract The development and rational utilization of regional water resources (RWR) is an important foundation for achieving comprehensive utilization of water resources and socio-economic progress. Socio-economic development has created necessary conditions and funds for the rational development of water resources, and the two support and constrain each other. Therefore, this article conducts a quantitative analysis of RWR to ensure the sustainable development of the economic and social (EAS) coupling system. An evaluation system was constructed based on feasibility analysis using the principal component analysis theory and entropy method. The results indicated that the interaction between RWR and EAS was relatively strong. In the seven-year survey, the coordinated development of the two showed an upward trend. The coupling and coordination indexes reached their lowest point in 2015 and have shown an upward trend. The coupling index increased by 0.34, and the coordination index increased by 0.21 to obtain a highly coordinated development state.

Climate Change and Hydrological Response in the Ranwu Lake Basin of Southeastern Tibet Plateau

It is of great practical significance to accurately distinguish the different water supply sources of rivers and lakes under climate change for regional water resources utilization. This study examines the impact of climate change on the hydrological processes of the Ranwu Lake basin in the southeastern Tibet Plateau. The authors used China Meteorological Forcing Dataset (CMFD) historical data, CanESM5′s future climate predictor, and the SPHY model to analyze trends in temperature, precipitation, and water supply sources in the basin. The study found that warming in the basin was higher than that in the Tibet Plateau, with high-altitude areas and winter showing more significant warming. From 1998 to 2018, precipitation in the basin showed a trend of fluctuation and decline. The study also found that glacial meltwater accounted for the majority of total runoff in the basin (54.13%), while snow meltwater, rainfall, and baseflow accounted for about 22.98%, 11.84%, and 11.06%, respectively, on average in recent years. The total runoff in the Ranwu Lake Basin will continue to decrease due to the accelerating retreat of glaciers, with the hydrological process transforming from being dominated by glacier processes to rain–snow processes. The study also predicts that three-quarters of glaciers in the basin will vanish within the next forty years, and by 2100, only around 20% of glaciers will remain.

Artificial Grassland Had Higher Water Use Efficiency in Year with Less Precipitation in the Agro-Pastoral Ecotone.

Improving plant water use efficiency is a key strategy for the utilization of regional limited water resources as well as the sustainable development of agriculture industry. To investigate the effects of different land use types on plant water use efficiency and their mechanisms, a randomized block experiment was designed in the agro-pastoral ecotone of northern China during 2020-2021. The differences in dry matter accumulation, evapotranspiration, soil physical and chemical properties, soil water storage and water use efficiency and their relationships among cropland, natural grassland and artificial grassland were studied. The results show that: In 2020, the dry matter accumulation and water use efficiency of cropland were significantly higher than those of artificial and natural grassland. In 2021, dry matter accumulation and water use efficiency of artificial grassland increased significantly from 364.79 g·m-2 and 24.92 kg·ha-1·mm-1 to 1037.14 g·m-2 and 50.82 kg·ha-1·mm-1, respectively, which were significantly higher than cropland and natural grassland. The evapotranspiration of three land use types showed an increasing trend in two years. The main reason affecting the difference of water use efficiency was that land use type affected soil moisture and soil nutrients, and then changed the dry matter accumulation and evapotranspiration of plants. During the study period, the water use efficiency of artificial grassland was higher in years with less precipitation. Therefore, expanding the planted area of artificial grassland may be one of the effective ways to promote the full utilization of regional water resources.

Identifying the factors controlling surface water and groundwater chemical characteristics and irrigation suitability in the Yarkant River Basin, northwest China

This study investigated the geochemical processes and the suitability for irrigation purposes of surface water and groundwater in the Yarkant River Basin, northwest China. The results showed that the surface water was moderately alkaline and neutral to slightly alkaline in the groundwater. The mean values for most ions in the groundwater were higher than those in the surface water. Geochemical method and hydrogen and oxygen isotope revealed that hydrochemical were mainly affected by dissolved evaporite minerals, ion exchange processes, and anthropogenic activities. Still, the geochemical processes of in surface water and groundwater were different. Additionally, three and four factors were extracted by factor analyses of surface water and groundwater, respectively, which distinguished the hydrochemical from natural origins and anthropogenic activities in more detail. The surface water and some groundwater in the south of the study area were suitable for irrigation processes. However, many groundwaters in the north were unsuitable for irrigation, because of their high sodium levels and salinity. The study results provide a theoretical basis for the sustainable utilization of regional water resources.

黄河流域植被格局变化对水分利用效率的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 黄河流域植被格局变化对水分利用效率的影响 DOI: 10.5846/stxb202201040020 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金专项项目(42041005, U2243203);第二次青藏高原科学考察研究项目(2019QZKK0304) Characteristics of water use efficiency during the changing process of vegetation in the Yellow River Basin Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:黄河流域横跨3个气候带,是全球人类活动最为强烈的地区之一,特殊的地理位置和复杂的下垫面导致其碳-水循环过程较为复杂。研究黄河流域碳水循环不仅是区域水资源利用的基础,也是实现气候变化条件下双碳目标的关键。水分利用效率(WUE)作为表征碳水过程的重要指标,可用于反映生态系统碳水耦合规律及其相互作用关系。基于此,利用全球陆表特征参量数据(GLASS)的净初级生产力(NPP)和蒸散(ET)产品以及中国逐年土地利用与覆盖数据集(CLUD-A),分析了黄河流域植被格局变化背景下WUE在1990-2018年的时空变化特征及其驱动力。结果表明:(1)黄河流域全域WUE在29 a的均值处在0.18-1.53 g C/kg H2O之间,存在明显的空间异质性,上游地区WUE明显高于中下游地区,分别在0.66-0.92 g C/kg H2O和0.43-0.62 g C/kg H2O之间波动,二者均存在波动上升态势。(2)黄河流域全域WUE在以2000年为中间点的10 a的增速达到近29 a的峰值,流域植被格局变化所带来的流域内NPP与ET变化速率的异步性主导了WUE变化的空间异质性,其中81.10%的区域中WUE所呈现的增加趋势是由NPP增速高于ET增速所导致。(3)黄河流域全域WUE在未来会继续保持增加态势,且上游WUE增加的持续性强于中下游地区。 Abstract:The Yellow River Basin spans three climatic zones and is one of the regions of the most intense human activities in the world. The carbon-water cycle is complicated due to its special geographical location and the underlying surface. The study of the carbon-water cycles in the Yellow River Basin is not only the basis of regional water resource utilization but also the key to achieve dual carbon targets in the context of climate change. However, there are few reports about the carbon-water cycle at the whole basin scale. Water use efficiency (WUE), as an important indicator of carbon and water processes, can reflect the coupling law of carbon and water and their interaction in an ecosystem. Based on Net Primary Productivity (NPP) and Evapotranspiration (ET) data from GLASS and China's annual land-use/cover datasets, the temporal and spatial variation characteristics of WUE in the Yellow River Basin from 1990 to 2018 were analyzed, and the relationship between WUE, NPP and ET was discussed. The results are as follows: (1) the mean value of WUE in the Yellow River Basin was between 0.18 and 1.53 g C/kg H2O in 29 years. There was obviously spatial heterogeneity. The WUE in the upper reaches of the Yellow River Basin fluctuated in 0.66-0.92 g C/kg H2O and 0.43-0.62 g C/kg H2O in the middle and lower reaches, and both of them had a rising trend of fluctuation. (2) In the Yellow River Basin, the growth rate of WUE reached a peak during 1995-2014, which is the decade with the year 2000 as the midpoint. The spatial heterogeneity of WUE was generated by the desynchrony of NPP and ET changes. Over 81.10% of the Yellow River Basin showed an increasing trend of WUE because the growth rate of NPP was higher than that of ET. (3) WUE in both the upper, middle and lower reaches will continue to grow in the future. In addition, the increase of WUE in the upper reaches is more persistent than that in the middle and lower reaches. 参考文献 相似文献 引证文献

Evaluation of Adaptive Utilization Capacity of Water Resources and Analysis of Driving Element: A Case Study of Tarim River Basin

The research on the adaptive utilization of water resources (AUWR) is of great significance to improve the coordinated development among water resources, economic society, and ecological environment in complex environments, and to promote the development of adaptive utilization of regional water resources. Based on the calculation method of harmony theory and the calculation method of the comprehensive co-evolution model, this paper obtains the harmony degree and adaptive utilization capacity of water resources (AUCWR) of each subsystem in the Tarim River Basin (TRB), analyzes the main factors affecting the AUCWR, and finally compares the two methods. The results show that: (1) From 2004 to 2018, the AUCWR in the TRB has gradually improved (harmony theory method: from 0.43 in 2004 to 0.56 in 2018, with a growth rate of 30.23%; comprehensive co-evolution model method: from 0.37 in 2004 to 0.62 in 2018, with a significant increase of 67.57%) and (2) From the perspective of indicators, indicators such as per capita GDP, the proportion of non-agricultural output value in GDP, and per capita net income of rural residents have a greater impact on the AUCWR in the TRB. Using different calculation methods to analyze the temporal and spatial distribution characteristics of the AUCWR in the TRB has important guiding significance for the future development and utilization of water resources, economic and social development, and ecological environment protection.

Effects of Climate and Land Use Change on Agricultural Water Consumption in Baicheng County

Changes in climate and land type directly affect the transformation and utilization of regional water resources. To analyze the evolutionary characteristics and drivers of agricultural water consumption (AWC) in arid regions, the Baicheng County is selected as an example. Based on the meteorological and land use/cover data from 1990 to 2020, the Penman–Monteith model and sensitivity method were used for analysis. The results show that: (1) The water consumption of major crops during the growth period was increasing, which was caused by climate change and changes in agricultural planting structure. (2) The sensitivity of AWC to meteorological factors was as follows: mean temperature (1.56) > mean wind speed (0.6) > precipitation (−0.12) > sunshine duration (−0.06). Temperature and wind speed were the dominant factors contributing to increased water consumption in oasis agriculture. (3) The change in land type was more obvious, mainly in cultivated land and urban and rural residential land with obvious growth, while the area of water area, forestland, and grassland showed a decreasing trend. In the past 30 years, the increase in cultivated land has reached 24.32%. The increase in cultivated land area was an important reason for the increase in AWC.

Spatiotemporal heterogeneity and attributions of streamflow and baseflow changes across the headstreams of the Tarim River Basin, Northwest China

Understanding spatiotemporal heterogeneity of streamflow and baseflow and revealing their changes contributed by climatic factors and human activities in the alpine region of inland river basin are critical for regional water management. However, the hydrology heterogeneity in the alpine region has remained unclear, which limits the scientific understanding of the interaction mechanism between the hydrological cycle and terrain, and further constrains the effective utilization of regional water resources in the water-shortage areas. In this study, the hydrological process and regimes for headstreams of Tarim River Basin (HTRB) during 1985–2011 were simulated by the Soil and Water Assessment Tool. We systematically characterized the spatial and temporal patterns of streamflow and baseflow through geostatistical and trend analyses, and subsequently investigated their heterogeneity responses to climate change and human activities at different sub-basins and elevation zones. Results show that the spatial distributions of streamflow and baseflow are highly related to terrain and river direction. Increased trends in precipitation enhanced with altitude, whereas decreased trends in potential evapotranspiration (PET) weakened with altitude, meanwhile, increased trends in streamflow and baseflow of HTRB are most pronounced in mid-altitude areas during 1985–2011. The climate elasticities of streamflow and baseflow are highly reliant on the altitudinal gradient. Increases in streamflow and baseflow in high-lying areas are more sensitive to precipitation variation, while they are more sensitive to PET change in low-lying areas. The magnitude and change rate with altitude bands of the precipitation has greater effects on streamflow and baseflow variations than those of PET. Furthermore, the percentage of sub-basins where climate changes dominate streamflow variation in each elevation band increases with height but decreases abruptly at elevations above 5000 m. The percentage of sub-basins where climate changes dominate baseflow variations gradually decreases in elevation bands above 3000 m. Our results indicate that climate change rather than human activities dominants the variation in streamflow and baseflow in most sub-basins and elevation bands.

Spatial correlation of groundwater level with natural factors using geographically weighted regression model in the Choushui River Alluvial Fan, Taiwan

The groundwater of the Choushui River alluvial fan in Central Taiwan has been overexploited for a long time. It is essential to understand the factors governing changes in groundwater level (GWL) for the use of water resources. In this study, we first conducted a Mann–Kendall test to identify significant trends in the regional GWL and obtained its spatial characteristics using the Moran’s I index in the Choushui River alluvial fan. Furthermore, we established a geographically weighted regression (GWR) model to explore the spatial correlation between natural factors and GWL in dry and wet seasons from 1999 to 2019. The long-term trend analysis shows that the GWL of the Choushui River alluvial fan decline significantly. The Moran’s I index shows that the spatial distribution of GWL had a positive correlation in both dry and wet seasons. GWR model indicate that the GWL are affected by drainage density (Dd), slope (S), normalized difference vegetation index (NDVI), and precipitation (P) during the dry season, while Dd, S, NDVI, and wetness index (WI) have an effect on the GWL during the wet season. These results can not only describe the model applicability for exploring the relationship between natural factors and GWL but also be used as references for future regional water resource utilization and management.

Evolution of Sustainable Water Resource Utilization in Hunan Province, China

The demand for social and economic development has promoted research into water resources. The combined effects of natural conditions and human activities on regional water resource usage are not well understood. The sustainable utilization of water resources was assessed in terms of supply (e.g., precipitation) and demand (e.g., ecological water resources footprint (EFw)) sides in Hunan Province, China, from 2010 to 2019. The results showed that: (1) on the supply side, water resources were increased across Hunan Province. The spatial patterns of total water resources are significantly heterogeneous, with high values in the east and south, which are mainly affected by precipitation; (2) on the demand side, evapotranspiration was great in areas with high vegetation coverage. The EFw was high in relatively developed areas. The mean percentage of agricultural EFw remained dominant at approximately 60% with a steady decreasing trend, while that of eco-environmental EFw increased; and (3) the sustainable utilization of water resources in Hunan Province is generally rational. Moreover, the potential for water resource development and utilization is really significant in eastern and southern Hunan Province. The findings are beneficial in providing an important scientific basis for policymaking relating to the efficient utilization of regional water resources.

Analysis of the Coupling Characteristics of Water Resources and Food Security: The Case of Northwest China

Exploring the coupling characteristics of regional water resources and food security helps to promote the sustainable development of grain production and is of great significance for achieving global food security. From the aspects of regional “water supply”, “water use” and “water demand”, the coupling characteristics of water resources and food security were systematically revealed; the new challenges faced by regional food security from the perspective of water resources were clarified; and effective ways to promote the utilization of regional water resources and the sustainable development of grain production were explored. This paper took Northwest China, which is the most arid region, where water-resource utilization and food security are in contradiction, as the research area. The water-resource load index, the water footprint of grain production and the water-consumption footprint were used to quantify the regional water-resource pressure index, as well as the residential grain-consumption types, population urbanization, the industrial-grain-processing industry and their corresponding water-consumption footprints from 2000 to 2020. The coupling characteristics of water resources and food security were systematically revealed. The results showed the following: (1) In 2000–2020, the water-resource load index increased from 4.0 to 10.7, and the load level increased from III to I. At the same time, agricultural water resources were largely allocated elsewhere. (2) During the period, the food rations showed a significant decreasing trend, and the average annual reduction was 3.4% (p < 0.01). The water footprint of animal products increased, particularly for beef and poultry (the average annual growth rates were 9.9% and 6.3%, respectively). In addition, the water footprint of industrial food consumption increased by 297.1%. (3) With the improvement of the urbanization level, the water-consumption footprint increased by 85.9%. It is expected that the water footprint of grain consumption will increase by 39.4% and 52.3% by 2030 and 2040, respectively. Exploring how to take effective measures to reduce the water footprint to meet food-security needs is imperative. This study proposed measures to improve the utilization efficiency of blue and green water and reduce gray water and the grain-consumption water footprint from the aspects of regional planting-structure optimization potential, water-saving irrigation technology, dietary-structure transformation and virtual water trade; these measures could better relieve the water-resource pressure and promote the sustainable development of grain production and water-resource utilization.

Optimization of Drought Limited Water Level and Operation Benefit Analysis of Large Reservoir

As an important water conservancy engineering project, reservoir regulation plays a crucial role in the insurance of water resources supply and demand balance and sustainable development and utilization, especially during drought seasons. The drought limited water level (DLWL) is the characteristic controlling water level of reservoir regulation operation during dry seasons, and the construction of reliable controlling schemes of DLWL is of great significance for the improvement of regional water resources utilization efficiency. Therefore, basing on the variation analysis of water inflowing series and water resources utilization characteristics among different sectors of Meishan Reservoir in Shihe Irrigation Area of China, firstly, the Hausdorff Dimensional Fractal (HDF) method was applied to divide drought early-warning periods of Meishan reservoir. Then, the initial scheme of DLWL of reservoir was determined through reservoir water inflow and water supply processes analysis during each drought warning periods of different typical hydrological years. And finally, the optimal dynamic controlling scheme of DLWL, described by drought warning water level (DWWL) and drought depleted water level (DDWL) respectively, was eventually proposed in this study based on the establishment of simulation and regulation model of reservoir and irrigation areas system. Moreover, the reliability and effectiveness of the proposed optimal controlling scheme of DLWL was further testified in terms of drought risk analysis of reservoir and irrigation area system under typical consecutive and annual drought scenarios, and meanwhile, the agricultural crop yield loss risk due to drought events corresponding to different controlling schemes of DLWL was also determined. The related research findings of this study could be favorable and beneficial for guiding drought-resistance regulation of reservoir and irrigation area system during drought seasons and providing reasonable decision-making basis of water resources utilization schemes as well.