Subjects: Geosciences >> Hydrology submitted time 2024-04-15 Cooperative journals: 《干旱区科学》
Abstract： Quantitative assessment of the impact of climate variability and human activities on runoff plays a pivotal role in water resource management and maintaining ecosystem integrity. This study considered six sub-basins in the upper reaches of the Yangtze River basin, China, to reveal the trend of the runoff evolution and clarify the driving factors of the changes during 1956–2020. Linear regression, Mann-Kendall test, and sliding t-test were used to study the trend of the hydrometeorological elements, while cumulative distance level and ordered clustering methods were applied to identify mutation points. The contributions of climate change and human disturbance to runoff changes were quantitatively assessed using three methods, i.e., the rainfall-runoff relationship method, slope variation method, and variable infiltration capacity (Budyko) hypothesis method. Then, the availability and stability of the three methods were compared. The results showed that the runoff in the upper reaches of the Yangtze River basin exhibited a decreasing trend from 1956 to 2020, with an abrupt change in 1985. For attribution analysis, the runoff series could be divided into two phases, i.e., 1961–1985 (baseline period) and 1986–2020 (changing period); and it was found that the rainfall-runoff relationship method with precipitation as the representative of climate factors had limited usability compared with the other two methods, while the slope variation and Budyko hypothesis methods had highly consistent results. Different factors showed different effects in the sub-basins of the upper reaches of the Yangtze River basin. Moreover, human disturbance was the main factor that contributed to the runoff changes, accounting for 53.0%–82.0%; and the contribution of climate factors to the runoff change was 17.0%–47.0%, making it the secondary factor, in which precipitation was the most representative climate factor. These results provide insights into how climate and anthropogenic changes synergistically influence the runoff of the upper reaches of the Yangtze River basin.
Subjects: Geosciences >> Hydrology submitted time 2024-02-21 Cooperative journals: 《干旱区科学》
Abstract： Analysing runoff changes and how these are affected by climate change and human activities is deemed crucial to elucidate the ecological and hydrological response mechanisms of rivers. The Indicators of Hydrologic Alteration and the Range of Variability Approach (IHA-RVA) method, as well as the ecological indicator method, were employed to quantitatively assess the degree of hydrologic change and ecological response processes in the Yellow River Basin from 1960 to 2020. Using Budyko's water heat coupling balance theory, the relative contributions of various driving factors (such as precipitation, potential evapotranspiration, and underlying surface) to runoff changes in the Yellow River Basin were quantitatively evaluated. The results show that the annual average runoff and precipitation in the Yellow River Basin had a downwards trend, whereas the potential evapotranspiration exhibited an upwards trend from 1960 to 2020. In approximately 1985, it was reported that the hydrological regime of the main stream underwent an abrupt change. The degree of hydrological change was observed to gradually increase from upstream to downstream, with a range of 34.00%–54.00%, all of which are moderate changes. However, significant differences have been noted among different ecological indicators, with a fluctuation index of 90.00% at the outlet of downstream hydrological stations, reaching a high level of change. After the mutation, the biodiversity index of flow in the middle and lower reaches of the Yellow River was generally lower than that in the base period. The research results also indicate that the driving factor for runoff changes in the upper reach of the Yellow River Basin is mainly precipitation, with a contribution rate of 39.31%–54.70%. Moreover, the driving factor for runoff changes in the middle and lower reaches is mainly human activities, having a contribution rate of 63.70%–84.37%. These results can serve as a basis to strengthen the protection and restoration efforts in the Yellow River Basin and further promote the rational development and use of water resources in the Yellow River.
Subjects: Geosciences >> Hydrology submitted time 2024-02-21 Cooperative journals: 《干旱区科学》
Abstract： Groundwater quality assessment is important to assure safe and durable water use. In semi-arid areas of Algeria, groundwater represents the main water resource for drinking water supply of the rural population as well as for irrigation of agricultural lands. Groundwater samples from wells and springs were collected from the Gargaat Tarf and Annk Djemel sub-watersheds of the Oum El Bouaghi, Algeria, and were analyzed and compared with the World Health Organization (WHO) standards. Results showed that most of the measured physical and chemical parameters exceeded the quality limits according to the WHO standards. Groundwater had a slightly alkaline water pH (7.00–7.79), electrical conductivity>1500 µS/cm, chloride>500 mg/L, calcium>250 mg/L, and magnesium>155 mg/L. Water quality index (WQI) results showed that 68% of the area had excellent water quality, 24% of the samples fell into good category, and only 8% were of poor quality and unsuitable for human consumption. Six wells in the area showed bacterial contamination. Total coliforms (453.9 (±180.3) CFU (colony-forming units)/100 mL), fecal coliforms (243.2 (±99.2) CFU/100 mL), and fecal streptococci (77.9 (±32.0) CFU/100 mL) loads were above the standard limits set by the WHO. These results confirmed that water resources in the study area were strongly influenced by anthropogenic activities and were not recommended for consumption as drinking water.
Subjects: Geosciences >> Hydrology submitted time 2024-02-07 Cooperative journals: 《干旱区科学》
Abstract： Groundwater quality assessment is important to assure safe and durable water use. In semi-arid areas of Algeria, groundwater represents the main water resource for drinking water supply of the rural population as well as for irrigation of agricultural lands. Groundwater samples from wells and springs were collected from the Gargaat Tarf and Annk Djemel sub-watersheds of the Oum El Bouaghi, Algeria, and were analyzed and compared with the World Health Organization (WHO) standards. Results showed that most of the measured physical and chemical parameters exceeded the quality limits according to the WHO standards. Groundwater had a slightly alkaline water pH (7.00–7.79), electrical conductivity>1500 µS/cm, chloride>500 mg/L, calcium>250 mg/L, and magnesium>155 mg/L. Water quality index (WQI) results showed that 68% of the area had excellent water quality, 24% of the samples fell into good category, and only 8% were of poor quality and unsuitable for human consumption. Six wells in the area showed bacterial contamination. Total coliforms (453.9 (±180.3) CFU (colony-forming units)/100 mL), fecal coliforms (243.2 (±99.2) CFU/100 mL), and fecal streptococci (77.9 (±32.0) CFU/100 mL) loads were above the standard limits set by the WHO. These results confirmed that water resources in the study area were strongly influenced by anthropogenic activities and were not recommended for consumption as drinking water.
Subjects: Geosciences >> Hydrology submitted time 2024-02-07 Cooperative journals: 《干旱区科学》
Abstract： Analysing runoff changes and how these are affected by climate change and human activities is deemed crucial to elucidate the ecological and hydrological response mechanisms of rivers. The Indicators of Hydrologic Alteration and the Range of Variability Approach (IHA-RVA) method, as well as the ecological indicator method, were employed to quantitatively assess the degree of hydrologic change and ecological response processes in the Yellow River Basin from 1960 to 2020. Using Budyko's water heat coupling balance theory, the relative contributions of various driving factors (such as precipitation, potential evapotranspiration, and underlying surface) to runoff changes in the Yellow River Basin were quantitatively evaluated. The results show that the annual average runoff and precipitation in the Yellow River Basin had a downwards trend, whereas the potential evapotranspiration exhibited an upwards trend from 1960 to 2020. In approximately 1985, it was reported that the hydrological regime of the main stream underwent an abrupt change. The degree of hydrological change was observed to gradually increase from upstream to downstream, with a range of 34.00%–54.00%, all of which are moderate changes. However, significant differences have been noted among different ecological indicators, with a fluctuation index of 90.00% at the outlet of downstream hydrological stations, reaching a high level of change. After the mutation, the biodiversity index of flow in the middle and lower reaches of the Yellow River was generally lower than that in the base period. The research results also indicate that the driving factor for runoff changes in the upper reach of the Yellow River Basin is mainly precipitation, with a contribution rate of 39.31%–54.70%. Moreover, the driving factor for runoff changes in the middle and lower reaches is mainly human activities, having a contribution rate of 63.70%–84.37%. These results can serve as a basis to strengthen the protection and restoration efforts in the Yellow River Basin and further promote the rational development and use of water resources in the Yellow River.
Subjects: Geosciences >> Hydrology submitted time 2024-02-07 Cooperative journals: 《干旱区科学》
Abstract： Groundwater quality assessment is important to assure safe and durable water use. In semi-arid areas of Algeria, groundwater represents the main water resource for drinking water supply of the rural population as well as for irrigation of agricultural lands. Groundwater samples from wells and springs were collected from the Gargaat Tarf and Annk Djemel sub-watersheds of the Oum El Bouaghi, Algeria, and were analyzed and compared with the World Health Organization (WHO) standards. Results showed that most of the measured physical and chemical parameters exceeded the quality limits according to the WHO standards. Groundwater had a slightly alkaline water pH (7.00–7.79), electrical conductivity>1500 µS/cm, chloride>500 mg/L, calcium>250 mg/L, and magnesium>155 mg/L. Water quality index (WQI) results showed that 68% of the area had excellent water quality, 24% of the samples fell into good category, and only 8% were of poor quality and unsuitable for human consumption. Six wells in the area showed bacterial contamination. Total coliforms (453.9 (±180.3) CFU (colony-forming units)/100 mL), fecal coliforms (243.2 (±99.2) CFU/100 mL), and fecal streptococci (77.9 (±32.0) CFU/100 mL) loads were above the standard limits set by the WHO. These results confirmed that water resources in the study area were strongly influenced by anthropogenic activities and were not recommended for consumption as drinking water.
Subjects: Geosciences >> Hydrology submitted time 2023-10-17 Cooperative journals: 《干旱区科学》
Abstract：The wide valley of the Yarlung Zangbo River is one of the most intense areas in terms of aeolian activity on the Tibetan Plateau, China. In the past, the evaluation of the intensity of aeolian activity in the QuxuSangri section of the Yarlung Zangbo River Valley was mainly based on data from the old meteorological stations, especially in non-sandy areas. In 2020, six new meteorological stations, which are closest to the new meteorological stations, were built in the wind erosion source regions (i.e., sandy areas) in the QuxuSangri section. In this study, based on mathematical statistics and empirical orthogonal function (EOF) decomposition analysis, we compared the difference of the wind regime between new meteorological stations and old meteorological stations from December 2020 to November 2021, and discussed the reasons for the discrepancy. The results showed that sandy and non-sandy areas differed significantly regarding the mean velocity (8.3 (0.3) versus 7.7 (0.3) m/s, respectively), frequency (12.9% (6.2%) versus 2.9% (1.9%), respectively), and dominant direction (nearly east or west versus nearly north or south, respectively) of sand-driving winds, drift potential (168.1 (77.3) versus 24.0 (17.9) VU (where VU is the vector unit), respectively), resultant drift potential (92.3 (78.5) versus 8.7 (9.2) VU, respectively), and resultant drift direction (nearly westward or eastward versus nearly southward or northward, respectively). This indicated an obvious spatial variation in the wind regime between sandy and non-sandy areas and suggested that there exist problems when using wind velocity data from non-sandy areas to evaluate the wind regime in sandy areas. The wind regime between sandy and non-sandy areas differed due to the differences in topography, heat flows, and their coupling with underlying surface, thereby affecting the local atmospheric circulation. Affected by large-scale circulations (westerly jet and Indian monsoon systems), both sandy and non-sandy areas showed similar seasonal variations in their respective wind regime. These findings provide a credible reference for re-understanding the wind regime and scientific wind-sand control in the middle reaches of the Yarlung Zangbo River Valley.
Subjects: Geosciences >> Hydrology submitted time 2023-08-26 Cooperative journals: 《干旱区研究》
Abstract： This study focuses on the Guanting and Miyun reservoirs in the capital water conservation functionalarea to evaluate water area changes and analyze the impact of precipitation, vegetation coverage, and humanwater consumption since 1980. The study used long-term remote sensing images from 1980 to 2022 to extract thewater area of each reservoir and calculate vegetation coverage. Pearson correlation analysis was used to explorethe correlation between the three impact factors. We found that the water area of both reservoirs continuouslyincreased, with historical highs since 2013, indicating significant water conservation achievements since the 18thNational Congress of the Communist Party of China. In the past 40 years, the water area change process of thetwo reservoirs has significantly synchronized, with five different periods, including rising, high levelmaintenance, falling, ground feature maintenance, and recovery periods. There was no correlation betweenannual precipitation and reservoir area in the Zhangjiakou section upstream of the reservoir and also nocorrelation between precipitation and reservoir area in June and July during the same period. The vegetationcoverage in the Zhangjiakou section upstream of the Guanting reservoir had an overall upward trend, with 2000being a variation point. The vegetation coverage of the Zhangjiakou section upstream of the Miyun reservoircontinues to stabilize at a level of 0.7. Correlation analysis shows that there is no correlation between vegetationcoverage and reservoir water area. The artificial water consumption in the Zhangjiakou section of the YongdingRiver Basin decreased by 20 million m3 per year since 2000, showing a significant negative correlation with thewater area of the Guanting reservoir and effectively increasing the inflow volume of the reservoir since 2019. Thecentralized water conveyance and water diversion from the Yellow River have had a significant impact on thewater area of the Guanting reservoir and on ecological water replenishment along the river. Future research isneeded to comprehensively evaluate the water conservation effectiveness of Zhangjiakou in terms of surfacerunoff into the reservoir, groundwater recovery, and ecological water replenishment.
Subjects: Geosciences >> Hydrology submitted time 2023-08-25 Cooperative journals: 《干旱区研究》
Abstract： Investigating the variable features of Kunlun glacier lakes is crucial for the development of the localecological environment. The area and number of glacial lakes in the Kunlun Mountains have changed over thepast 20 years, and this paper used supervised classification based on the Google Earth Engine remote sensingcloud platform to study the changes. It also examined the driving factors of temperature, precipitation, and glacierarea. The findings indicate: (1) There were 39.25% more glacial lakes in the Kunlun Mountains in 2020 thanthere were in 2000, and the area expanded by 81.35%, with a distribution pattern of more lakes in the west andfewer lakes in the east. (2) The Kunlun Mountain glacial lakes are primarily found at an altitude of 4600-5600 m,and the number and area of glacial lakes account for 71.58% and 70.51% of the total, respectively. These glaciallakes have a smaller area than 0.1 km2 and are more sensitive to climate change. (3) The temperature and precipitationin the Kunlun Mountains declined by 3.45%, 6.27%, and 21.15% from 2000 to 2020, respectively, as didthe glacier area. The primary cause of the expansion of glacial lakes is the meltwater produced by glacier melting.The study’s findings may provide empirical justification for the preservation and use of water resources as wellas for catastrophe warnings in dry regions.
Subjects: Geosciences >> Hydrology submitted time 2023-08-25 Cooperative journals: 《干旱区研究》
Abstract： Understanding the dynamic process of evapotranspiration and its causes is crucial for water resourcestability, ecological and environmental security, and agricultural water resource management in arid Central Asia.Evapotranspiration is the connection between the water-energy-carbon cycle. This study used the Priestley-Taylordiurnal land surface temperature range (PT- DTsR) model to calculate and analyze the spatial and temporalvariability of evapotranspiration in arid Central Asia from 2000 to 2019. It also used the Lindeman- Merenda-Gold method to quantitatively evaluate the absolute contributions of various drivers to each component ofevapotranspiration. By weighing each component’s contribution to the change in evapotranspiration, thecontribution of each driver to evapotranspiration was assessed. According to the findings, evapotranspirationincreased in dry Central Asia at a rate of 1.45 mm per year, and its pattern indicates that it increased in the eastand decreased in the west. The changes in transpiration, evaporation, and interception were 2.46 mm·a-1, -1.03mm·a- 1, and 0.02 mm·a- 1, respectively. These three trends contributed 70.09%, 29.34%, and 0.57%, to thechange in evapotranspiration. With an absolute contribution of 28.16%, Normalized Difference Vegetation Index(NDVI) is the key driver of evapotranspiration fluctuations in arid Central Asia.
Subjects: Geosciences >> Hydrology submitted time 2023-08-25 Cooperative journals: 《干旱区研究》
Abstract： In dry and semi- arid environments, non- rainfall water is crucial for water balance and ecology andenhances regional water intake. To preserve ecological equilibrium, non- rainfall water may be a crucial watersupply. However, owing to the longer wetting period of leaves, non- rainfall water may also contribute to thespread of diseases. This work discusses the measurement and modeling methodologies of dew, fog, and watervapor adsorption, examines the research development of dew, fog, and water vapor adsorption, and does adynamic analysis of bibliometric hot spots to enhance our knowledge on non-rainfall water. The findings indicatethat there is a minor movement of non-rainfall water between the ground and the atmosphere. Utilizing uniquecondensers will result in significant condensation. Pyramid condensers are more effective in collecting dew thanplane condensers. Since non-rainfall water exhibits clear temporal and geographical fluctuation, it is difficult tomonitor in real- world settings, which restricts relevant research. The regional focus is on non- rainfall waterresearch. Studies on fog water mostly concentrate on coastal and mountainous locations, whereas studies on dewprimarily concentrate on the site scale in arid and semi-arid regions. Water vapor adsorption typically takes placeon dry ground. A hub for research on non-rainfall water is the Negev Desert in southern Israel. The focus of thisstudy is on the collection and use of non-rainfall water and its impact on the environment’s ecology. The watercycle and the carbon biogeochemical cycle in arid and semi-arid regions are affected by the interaction betweennon- rainfall water and biological crust. Recently, the study on the interaction between non- rainfall water andbiological crusts has grown radically. Understanding the origins and evolution of coastal fog is crucial to enhancethe precision of coastal fog forecasts by considering all relevant meteorological, climatic, and boundary layerfactors. The modeling of soil moisture adsorption remains a significant obstacle, nevertheless. Precipitation is lessconcentrated in heavy isotopes than dew or fog water. The stable isotope technique is a useful tool for researchingthe ecohydrological impacts of dew and fog water due to the variation in isotope composition. More research hasbeen done on dew than on fog water or soil moisture adsorption. However, extensive regional research is limited,including long-term studies on non-rainfall water or studies on natural surface condensation. Current studies onnon- rainfall water are unable to provide a comprehensive grasp of its spatiotemporal variance. Future researchmust discover and develop new technologies and new methods to collect, observe, and model non-rainfall wateron natural surfaces, investigate the large spatial scale and long-term non-rainfall water observation and simulation,and reveal influences of non-rainfall water on the water cycle, eco-hydrology, and climatic change to deepen theunderstanding of non-rainfall water as a nontraditional water resource.
Subjects: Geosciences >> Hydrology submitted time 2023-05-30 Cooperative journals: 《干旱区研究》
Abstract： Climate change and human activities are the main driving forces of river runoff variation. Under the similar weather condition (SWC), human activities are the dominant factors for change of discharge in the basin that quantitative identification on the action mechanism of human activities on runoff change has great significance to further explore the change characteristics of runoff. This study was conducted in the Yue River basin of the Qinling Mountains. Combined with Land-Use and Land-Cover Change (LUCC) as well as Normalized Difference Vegetation Index (NDVI), human activities’impacts on runoff is quantified by analyzing runoff changes in the Yue River basin with similar weather condition. The results show that: the average runoff value from 1960 to 2018 is 8.3×108 m3. The discharge shows a decreasing trend as a whole, and the change trend is not significant. Under the similar weather condition, this research obtains 6 paired- years. Among them, the annual runoff of 3 paired-years increased and that of 2 paired-years decreased. Taking the third paired-year (2000 and 2016) as an example to quantitatively distinguish the impact of climate change and human activities on runoff which reduced by 4.7 × 108 m3 in 2016 compared with 2000. In the third paired- year (2000 and 2016), 25751.4 hm2 of arable land was converted into forest land, and the forest land area increased by 24998.9 hm2. The NDVI change is mainly caused by human activities. The area increased by NDVI in 2016 was 242652.0 hm2 compared with that in 2000. The change trend of NDVI is opposite to that of runoff. This study can provide a theoretical basis for quantitative evaluation for human activities’impact on river runoff changes within the Qinling Mountains.
Subjects: Geosciences >> Hydrology submitted time 2023-05-30 Cooperative journals: 《干旱区研究》
Abstract： To shed light on the complex transboundary water problems in Central Asia, a study on water-energy food- ecology (WEFE) system coordination was conducted from the regional and national levels based on a system coupling perspective. First, the WEFE evaluation index system for coupling and coordination was constructed, and then the coupling coordination degree model was applied to quantitatively evaluate the level of coordinated development of WEFE and its spatial and temporal evolution in Central Asia. The results show that: (1) In the last 20 years, the coupling degree of WEFE in Central Asia basically maintained a high level, and the coupling coordination degree showed a slow growth trend but was barely coordination. (2) The development level of coupling coordination varied greatly among countries, and the coupling coordination level of Kazakhstan was the best, albeit in primary coordination. Tajikistan and Kyrgyzstan barely performed coordination, and Turkmenistan and Uzbekistan were on the brink of misalignment. (3) Comparing the development levels of multiple systems, it was found that there was a significant lag in the food system in Tajikistan and Kyrgyzstan, a lag in the water system in Turkmenistan, and a lag in the energy system in Kazakhstan and Uzbekistan, which failed to achieve a good match among systems and affected the regional coordinated development to a certain extent. The results can provide a basis for decision-making on the synergistic development of WEFE in Central Asia and transboundary river development cooperation among countries.
Subjects: Geosciences >> Hydrology submitted time 2023-05-17 Cooperative journals: 《干旱区地理》
Abstract： The Kashi River is one of the three major tributaries of the Ili River, Xinjiang, China, and it is important to understand the water quality condition of the watershed for ecological protection in the Ili region. By analyzing the water chemistry composition of the Kashi River Basin and its causes, and using it as a basis for irrigation suitability evaluation of the river. By collecting 289 sets of water samples from the Kashi River, 5 sets of water samples from springs, and 30 sets of water samples from wells during July 2018—2021, the spatial and temporal variation characteristics and controlling factors of water chemistry in the Kashi River Basin were explored by applying mathematical statistics, Piper’s trilinear diagram, Gibbs diagram, and ion proportional relationship, and using USSL diagram, Wilcox diagrams were used to evaluate the suitability of river water for irrigation. The results show that: (1) All water bodies in the Kashi River Basin are weakly alkaline, the total dissolved solids and electrical conductivity (EC) of well water and spring water are slightly larger than those of river water, and the water chemistry type of each water body is Ca2 + -HCO3 - type. (2) Rock weathering is the main controlling factor for the ion source of each water body in the watershed, and the ion source of each water body is mainly affected by carbonate rock weathering. (3) The ion mass concentration of river water varies gently over a short time series, indicating that the ion concentration in the mainstem from 2018 to 2021 varies by the strength of the dilution effect of ice and snow melt and precipitation, being lower from April to July and higher from August to March; the ion mass concentration varies spatially with increasing elevation and the ion mass concentration decreases with the increase of elevation. (4) The water quality of the river is excellent and can be used directly as irrigation water, but the EC in 2021 has a slightly increasing trend. The results of the study can provide a basis for the sustainable use and scientific development and management of water resources in the Kashi River Valley.
Subjects: Geosciences >> Hydrology submitted time 2023-04-07 Cooperative journals: 《干旱区地理》
Abstract： This study takes the grain and cotton cropping systems as an example to measure the development level of the water resource and agricultural cropping systems in Xinjiang, China to study its water resource endowment and agriculture industry development, respectively. Additionally, the two systems are combined to further analyze the coupling coordination and spatiotemporal differences of the water resources- agriculture cropping composite system (abbreviated composite system) in Xinjiang. Therefore, data related to water resources and agriculture cropping of 14 prefectures in Xinjiang from 2005 to 2019 were selected to measure the comprehensive development index of water resources, agriculture cropping, and composite systems using the entropy method. On the basis of the comprehensive development index of the composite system, this study further explores the coupling coordination trend and spatiotemporal evolution law of the composite system using the coupling coordination degree model and exploratory spatial data analysis, respectively. The following results are presented. (1) The comprehensive development index of the composite system in Xinjiang is spatially characterized by“high in the middle and low on both sides”. Among them, the level of comprehensive development index of the water resources system is higher than that of the agriculture cropping system and the growth trend of the agricultural plantation system is fast. Comparing the results of the composite development index of water resources and agriculture cropping systems from 2005 to 2019, this study found that the former has been developing at a higher level than the latter during the study period. However, the latter showed a faster growth trend than the former, resulting in a gradual reduction in the gap between the two systems. (2) The overall level of coupling coordination of composite systems in Xinjiang shows a development trend of“high in the north and low in the south, but the gap is gradually decreasing”. Additionally, the agriculture cropping system has gradually become a shortcoming that hinders the development of the coupling coordination of composite systems due to the differences among regions. (3) A significant spatial clustering characteristic of the coupling coordination degree of the composite system is also observed in Xinjiang, but its positive correlation shows a changing trend from strong to weak. The spatial clustering type is mainly“high-high and low-low”clustering, and the coupling coordination degree of the composite system shows spillover effects and is easily influenced by the neighboring areas. The results of this study have theoretical and practical implications for the sustainable use of water resources, the development of the agriculture cropping industry, and the benign coordination of the two in Xinjiang.
Subjects: Geosciences >> Hydrology submitted time 2023-03-28 Cooperative journals: 《干旱区研究》
Abstract： River canal leakage is the main mode of surface water replenishment to soil water for desert riverbank ecological protection, plant water absorption, and utilization. It is also an important cause of soil salinization during increased groundwater level periods. Therefore, studying the movement of groundwater and soil moisture under the condition of canal leakage recharge in arid areas can be crucial not only for constructing a benign ecological circulation system dominated by water environment, but also for preventing soil salinization. This study used laboratory simulation experiment to analyze the capillary water movement characteristics in loamy sand under different water levels in Yarkant River irrigation area. Results showed a decreasing trend in the capillary water supply rate, which could be subdivided into three stages, including rapid decrease, linear decrease, and stable- state, while the average stable recharge rate 0.02 mm · min- 1 was detected. The rising height of capillary water and rising rate both had parabola relationships with the recharge time. Validation of the linear relationship between capillary water recharge and rising height of capillary water under different canal water levels revealed that the slope (B) was equal to the difference between the mean soil water content (θmean) and initial water content (θi), while B values under different canal water levels ranged from 0.3155 to 0.4046 cm3·cm-3, with a mean value of 0.3695 cm3 ·cm- 3. A linear correlation was detected between capillary water supply rate and the reciprocal value of rising height of capillary water. The improved Green-Ampt model could successfully be used to simulate capillary water rise process in a homogeneous loamy sand. Overall, these results could potentially provide clues for studying the restoration and reconstruction of ecologically protected plants in canals, and for the prevention of soil salinization in arid areas.
Subjects: Geosciences >> Hydrology submitted time 2023-03-28 Cooperative journals: 《干旱区研究》
Abstract： Water shortage has become a major resource and environmental challenge worldwide. Climate and land use change have made the evolution of current hydrological factors complex and uncertain. Exploring the spatial distribution characteristics of hydrological factors under dynamic scenarios is of vital theoretical and practical significance for the sustainable development of regional economy and society. The meteorological and hydrological data of the Datong River source region from 1960 to 2019 were used in this study to quantitatively analyze the spatial distribution characteristics of hydrological elements under climate and land use change scenarios based on model simulation and scenario segmentation. The results showed that: (1) After calibration and verification of the SWAT model, the coefficient of determination, Nash coefficient, and percentage bias (PBIAS) all met the model requirements of 0.81%, 0.79%, and −0.8% in the rate period, and 0.81%, 0.75%, and 15.8% in the validation period, respectively, which indicated that the model had good applicability in the headwaters of the Chase River. (2) Obvious spatial heterogeneity of hydrological elements was detected in the headwater area of Datong River, and a single hydrological element could not represent the overall spatial distribution. Precipitation, potential evapotranspiration, and soil water content decreased with the increase in altitude, while surface runoff and water yield increased with the increase in altitude. (3) The spatial distribution of hydrological factors under the three scenarios were generally consistent, while the spatial distribution of water yield was greatly affected by the land use change. Under the climate change scenario, the actual evapotranspiration and soil water content showed a downward trend, while the surface runoff and water yield showed an upward trend. Under the land use change scenario, the changes of hydrological elements were contrary to these observations.
Subjects: Geosciences >> Hydrology submitted time 2023-03-14 Cooperative journals: 《干旱区地理》
Abstract： Groundwater is important for regulating the water cycle and ecosystem in arid areas. Understanding and managing groundwater resources is the key to preventing the reduction of river baseflow, ground subsidence and water quality degradation. Therefore, this study analyzed the groundwater chemical parameters and hydrogenoxygen stable isotope characteristics of the Ebinur Lake Basin, Xinjiang, China, and explored the sources of groundwater recharge, dynamic changes of water chemical components in different regions by combining linear regression, two-terminal mixed model and GIS spatial analysis. The results showed that: (1) Different circulation processes of groundwater existed in different areas of the Ebinur Lake Basin, with the largest of hydrogen and oxygen isotopes (δ2 H and δ18O) in the middle and lower reaches of the Bortala and Jing Rivers, followed by the area around Lake Ebinur Basin, and the smallest in the upper Bortala River area. (2) Deuterium excess parameter (d-excess) parameter and hydrochemical composition of groundwater reflected different groundwater recharge mechanisms and influencing factors. Groundwater in the upper Bortala River area was mainly recharged by glacial snow melt water. The main sources of groundwater in the middle and lower reaches of the Bortala and Jing Rivers were surface water and precipitation, which were also greatly influenced by the nature of rock formations, farmland development and irrigation measures. Groundwater around Lake Ebinur Basin mainly came from snow and ice melt and precipitation. The middle and lower reaches and groundwater in the river and lake confluence areas are the key areas for pollution prevention and control and management. (3) Different hydraulic connections existed in underground aquifers. The electrical conductance (EC) of flow system I ranged from 210.00 μS·cm-1 to 2500.00 μS·cm-1 , and the d-excess ranged from 6.47‰ to 9.70‰. The EC of flow system II ranged from 141.60 μS·cm-1 to 5260.00 μS·cm-1 , and the d-excess ranged from 9.61‰ to 17.45‰. In conclusion, this study investigated the driving mechanisms of hydrogen and oxygen isotopes and water chemistry in groundwater in the Lake Ebinur Basin, which provided some theoretical reference for the rational use and scientific development of groundwater resources in the basin.
Subjects: Geosciences >> Hydrology submitted time 2023-03-14 Cooperative journals: 《干旱区地理》
Abstract： The Mongolian Plateau is a sensitive area for coping with global changes. It is also the only place for three of the nine routes of migratory birds. Lakes play the role of“indicator”and“life posthouse”in the plateau ecological environment. Relatively few research results have been presented on the changes of lakes in the Mongolian Plateau at home and abroad. Most of them focused on the analysis of typical and large lakes. Research on their causes has focused on meteorological and human factors, while that on small lakes and the relationship between the lake area and the soil environmental factors are relatively weak. Based on the Landsat remote sensing imagery, the information of the lake area above 1 km2 per year on the Mongolian Plateau from 2000 to 2020 was extracted by the MNDWI water body index. The results of the temporal and spatial change characteristic analysis of the lake area showed that: (1) The area and the number of lakes have decreasing and increasing trends before and after 2009, respectively. Overall, the area and the number of lakes depicted a decreasing trend from 2000 to 2020. (2) The changes of lakes of different grades were quite different. The changes of the super large- and medium-sized lakes were relatively stable. Furthermore, the large-sized lakes showed the largest reduction. (3) The changes of the lakes in different regions also differed. These changes in the northwest were relatively stable, while those in the central and eastern regions were more dramatic. (4) Before 2009, the number of lakes in the dense areas in the central and eastern regions decreased, resulting in the weakening of the spatial distribution agglomeration of lakes in the study area. After 2009, the newly added lakes in the sparse area in the central region were scattered, weakening their spatial distribution agglomeration. (5) The correlation between the lake area and the annual average temperature, annual precipitation, annual evaporation, vegetation index, and four layers of soil moisture was relatively significant. The degree of influence exhibited in the two time periods significantly differed. Mastering the temporal and spatial changes of the lake in the Mongolian Plateau and their causes can provide a reference for the climate regulation, biodiversity protection, and climate disaster reduction research in the Mongolian Plateau and the whole world.
Subjects: Geosciences >> Hydrology submitted time 2023-03-14 Cooperative journals: 《干旱区地理》
Abstract： Based on the runoff data and meteorological data of Laohugou watershed in the western of Qilian Mountains, northwest China, the research analyzed the relationship between runoff and meteorological variables in glacier area, and established a multivariate exponential nonlinear regression to reconstructe the runoff. In addition, the characteristics of interannual, seasonal, diurnal variations of runoff in the glacial region were analyzed. The results showed that: (1) The correlation between runoff and temperature is the highest (0.86), followed by water vapor pressure (0.81), relative humidity (0.46), and precipitation (0.27). Runoff is most affected by temperature. (2) The mean daily runoff is 2.10 m3 ·s -1 in this century, which is higher than 1.65 m3 ·s -1 in the late 1950s, the main reason is that the temperature increased by 0.75 ℃ in the ablation season. The interannual variation of runoff is large in the strong ablation period, and the interannual variation is small in the beginning (May-June) and end (September) of the ablation period. The proportion of runoff generation from May to September was 5.3%, 16.1%, 37.3%, 35.1% and 6.2%, respectively. (3) Multivariate exponential nonlinear regression equation can better simulate the daily runoff (the mean Nash efficiency coefficient is 0.70). After the supplement of the missing runoff, the diurnal variation of runoff is small in the beginning and end of the ablation period, but the diurnal variation of runoff is large in the strong ablation period. For the time-lag effect of runoff, monthly runoff in Laohugou watershed showed a characteristic of diurnal variation of“valley-peak”during the ablation period. The time interval between the maximum temperature and the maximum runoff was long in the beginning and end of the ablation period, while the time interval was short between the maximum temperature and the maximum runoff during the strong ablation period, and the maximum difference between the maximum temperature and the maximum runoff was 3 hours in June.
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