Inland River Research Articles

Impacts of climate change on glacial retreat during 1990–2021 in the Chinese Altay Mountains

Melting glaciers have changed the spatial–temporal distribution of water resources in inland river basins and are one of the important inducements of extreme hydrological events. Most previous studies on glacier changes in the Chinese Altay Mountains have focused on the period 1960–2011; however, there is a lack of glacier data reflecting recent changes (1990–2021) over the past decades, and the response of glaciers to regional climate change is still unclear. In this study, Landsat images and the Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) were used to map glacier outlines from 1990 to 2021 for the whole region and its surrounding areas, and the impacts of temperature, precipitation, and solar radiation variation on glacier retreat were investigated. The results indicate that (1) the glacier area retreat rate of 0.55 %∙a-1 in the Chinese Altay Mountains during 1990–2021 is obviously lower than the glacier area shrinkage rate of 0.75 %∙a-1 from 1960 to 2009, and the retreat rate of glacier volume is 0.60 %∙a-1. (2) More than 80 % of the total glacier area located at elevation ranged from 2600 to 3400 m, and the greatest glacier area loss occurred within the elevation range of 2800–3000 m. Although the glacier area was retreating in all orientations, the south-facing glacier has the largest retreat rate. (3) The rate of change of glacier area was −1.26 %∙a-1, −0.71 %∙a-1 and −0.51 %∙a-1 in the Haba sub-basin, Sawir Mountains region, and Burqin sub-basin, respectively. (4) Owing to the slowdown in the warming rate since 1990, the glacier shrinkage rate was moderate during 1990–2021 compared to the 1960 s–1980 s, and contribution of the increase of solar radiation (35.72 %) and summer temperature (25.3 %) to glacier retreat from 1990 to 2021 were more prominent than other climate factors.

Spatio-Temporal Study on Irrigation Guarantee Capacity in the Northwest Arid Region of China

Irrigation guarantee capacity is the critical factor in evaluating the development level of irrigated agriculture and is also a future development trend. It is necessary to carry out scientific planning and reasonable allocation of irrigation water resources to ensure the sustainable development of irrigated agriculture and improve the efficiency and effectiveness of water resource utilization. This study is based on remote sensing meteorological data and the principles of the Miami model and water balance. We calculated the annual irrigation water requirement and effective irrigation water, and used the ratio between the effective irrigation water and irrigation water requirement as the basis for evaluating an irrigation guarantee capability index. By using irrigation guarantee capability evaluation indicators from multiple years, we evaluated and assessed the irrigation guarantee capability in the arid region of northwest China. In addition, we analyzed three indicators (i.e., irrigation water requirement IWR, effective irrigation water EIW, and irrigation guarantee capacity index IGCI) to explore the rational allocation of water resources in the northwest arid area. IWR, EIW, and ICGI in northwest China from 2001 to 2020 were analyzed, and the average values were 379.32 mm, 171.29 mm, and 0.50, respectively. Simultaneously, an analysis was conducted on the temporal and spatial distribution of IWR, EIW, and IGCI in the northwest region of China from 2001 to 2020. The results indicated that the rainfall in the southwestern edge of the Yellow River Basin and the eastern part of the Qaidam Basin could meet the irrigation water demand. The northwest edge of the Yellow River Basin, the central Hexi Inland River Basin, most of Northeast Xinjiang, central and southeastern Xinjiang, and other regions mainly rely on irrigation to meet agricultural water requirements. The rest of the region needs to rely on irrigation for supplementary irrigation to increase crop yield. All districts in the ‘Three Water Lines’ area of northwest China should vigorously develop sprinkler irrigation, micro-irrigation, pipe irrigation, and other irrigation water-saving technologies and support engineering construction. Under the premise of ensuring national food security, they should reduce the planting area of rice, corn, and orchards, and increase the planting area of economic crops such as beans and tubers in the ’Three Water Lines’ area. That is conducive to further reducing the agricultural irrigation quota and improving the matching degree of irrigation water resources. It provides a scientific reference for optimizing water resource allocation and improving irrigation water-use efficiency in northwest arid areas.

River logistics amid war and post-war recovery in Ukraine: current situation and prospects .

River logistics amid war and post-war recovery in Ukraine: current situation and prospects .

Agroecological Risk Assessment Based on Coupling of Water and Land Resources—A Case of Heihe River Basin

In the arid zone of northwest China, the Heihe River Basin (HRB), as a typical inland river basin, has a fragile regional ecological environment, obvious ecological degradation characteristics, and extremely serious problems in the utilization of agricultural land resources. Meanwhile, the shortage of water resources, the low reduction of land quality, and excessive agricultural activities have greatly increased the local water and land pressure. In this paper, firstly, using the Malmquist DEA model and coupling coordination degree model, the agroecological risk assessment system on account of the coupling of water and land resources (WLR) is constructed. Secondly, taking HRB from 1995 to 2020 as an example, we carry out spatial correlation analysis based on the degree of risk-correlated WLR. Thirdly, we analyze the evolution process and spatial correlation of ecological risk of agricultural WLR in the HRB at the county scale, then we conclude and put forward policy suggestions for improvement. The results show that: (1) On the whole, the average ecological risk of agricultural water resources in the HRB from 1995 to 2020 was 0.933, indicating that the risk was declining; the average ecological risk of agricultural land resources in the HRB from 1995 to 2020 was 0.938, indicating that the risk was declining also. (2) The degree of ecological risk coupling and coordination of agricultural soil and water resources upstream of the HRB is on the rise, while that in the middle and lower reaches is on the decline. (3) Through panel model analysis, the matching suitability of WLR drives agroecological risk. The correlation between them is positive. In conclusion, this method can effectively evaluate the agroecological risk of WLR and provide technical support for agricultural production and management in arid areas.

Joint scheduling of barges and tugboats for river–sea intermodal transport

In this paper, we study a barge and tugboat joint scheduling problem arising from a river–sea intermodal transport system, where non-self-propelled barges travel with the help of tugboats between an inland river bulk port and sea transshipment platforms to transport cargo. Due to limited channels and the sequential scheduling among ships, transit inefficiency and resource under-utilization often occur, thus it is essential to design barge timetables and tugboat paths. This paper jointly schedules barges and tugboats in a river–sea transshipment port with a tidally influenced channel, and focuses on barge round trips with multiple legs. We construct a state-space–time network from the perspective of tugboats, in which the state implies whether a barge is served by a tugboat. The problem is formulated as an integer programming model based on the network to minimize time taken for bulk cargo transshipment. A tailored variable neighborhood search algorithm is designed and its efficiency, effectiveness, and stability are demonstrated by numerical experiments, which are based on real data from the Boffa port. It is demonstrated that, by joint scheduling barges and tugboats, transfer efficiency can be significantly improved under limited tugboat resources and shorter tidal windows. The results also provide managerial insights on schedule and valuable conclusions about the resource allocation in the port.

Synergistic Change and Driving Mechanisms of Hydrological Processes and Ecosystem Quality in a Typical Arid and Semi-Arid Inland River Basin, China

Global warming and human activities are complicating the spatial and temporal relationships between basin hydrologic processes and ecosystem quality (EQ), especially in arid and semi-arid regions. Knowledge of the synergy between hydrological processes and ecosystems in arid and semi-arid zones is an effective measure to achieve ecologically sustainable development. In this study, the inland river basin Ulagai River Basin (URB), a typical arid and semi-arid region in Northern China, was used as the study area; based on an improved hydrological model and remote-sensing and in situ measured data, this URB-focused study analyzed the spatial and temporal characteristics of hydrological process factors, such as precipitation, evapotranspiration (ET), surface runoff, lateral flow, groundwater recharge, and EQ and the synergistic relationships between them. It was found that, barring snowmelt, the hydrological process factors such as precipitation, ET, surface runoff, lateral flow, and groundwater recharge had a rising trend in the URB, since the 20th century. The rate of change was higher in the downstream areas when compared with what it was in the upstream and midstream areas. The multi-year average of EQ in the basin is 53.66, which is at a medium level and has an overall improving trend, accounting for 95.14% of the total area, mainly in the upstream, downstream southern, and downstream northern areas of the basin. The change in relationship between the hydrological process factors and EQ was found to have a highly synergistic effect. Temporally, EQ was consistent with the interannual trends of precipitation, surface runoff, lateral flow, and groundwater recharge. The correlation between the hydrological process factors and EQ was found to be higher than 0.7 during the study period. Spatially, the hydrological process factors had a synergistic relationship with EQ from strong to weak upstream, midstream, and downstream, respectively. In addition, ecosystem improvements were accelerated by government initiatives such as the policy of Returning Grazing Land to Grassland Project, which has played an important role in promoting soil and water conservation and EQ. This study provides theoretical support for understanding the relationship between hydrological processes and ecological evolution in arid and semi-arid regions, and it also provides new ideas for related research.

Projection of Flash Droughts in the Headstream Area of Tarim River Basin Under Climate Change Through Bayesian Uncertainty Analysis

AbstractThe Tarim River, the largest inland river in China, sits in the Tarim River Basin (TRB), which is an arid area with the ecosystem primarily sustained by water from melting snow and glaciers in the headstream area. To evaluate the pressures of natural disasters in this climate‐change‐sensitive basin, this study projected flash droughts in the headstream area of the TRB. We used the variable infiltration capacity (VIC) model to describe the hydrological processes of the study area, Markov chain Monte Carlo to quantify the parameter uncertainty of the VIC model. Ten downscaled general circulation models from the Coupled Model Intercomparison Project Phase 6 (CMIP6) were used to drive the VIC model, and the standardized evaporative stress ratio was applied to identify flash droughts. The results demonstrated that the VIC model after Bayesian parameters uncertainty analysis can efficiently describe the hydrological processes of the study area. In the future (2021–2100), compared with the plain region, the alpine region has higher flash drought frequency and intensity. Compared with the historical period (1961–2014), the frequency, duration, and intensity of flash droughts tend to increase throughout the study area, especially for the alpine area. Moreover, based on variance decomposition, CMIP6 model is the most important uncertainty source for flash drought projection, followed by the shared socioeconomic pathway of climate change scenario and VIC model parameters.

Changes in Land Use Pattern and Structure under the Rapid Urbanization of the Tarim River Basin

Urbanization not only affects a region’s economic development but also impacts its land use structure. As the largest inland river basin in China, the Tarim River Basin has experienced rapid economic growth and urbanization in recent years, posing a serious threat to its soil and water resources and ecological sustainability. In this study, four remote sensing data products from 1990–2020 are selected to explore the distribution of land use types and their land structure changes in the basin in the context of rapid urbanization. The results show that the built-up land area increased by 2855.74 km2 during 1990–2020, mainly from the transfer of grassland and barren land. Furthermore, the migration of the center of gravity of built-up land moved from the desert to oasis areas, indicating that the urbanization process intensified during the study period. The overall trend is toward a continuous increase in arable and built-up land area and a continuous decrease in barren land. Future trends in the Tarim River Basin predict that arable land will decrease and that built-up land will continue to increase. However, the increase in built-up land will level off, mainly due to the transfer of arable land and grassland, which accounts for 37.94% and 20.40%, respectively. The migration characteristics of the center of gravity of each land type in the basin varied widely during 1990–2020, but the land structure will tend toward a gradual balance in the future. Therefore, in the context of increasing urbanization, focusing on the sustainable development of regional soil and water resources and ecology is crucial for the coordinated development of regional resources and economy.

A Novel Ship-Height Measurement System Based on Optical Axes Collinear Stereo Vision

Overheight ships pose serious danger to bridges when sailing along inland rivers. Measuring ship height from a long distance with high precision is a very challenging problem. This article proposes a novel optical axes colinear binocular stereo vision system to meet this goal. The system is equipped with two arrays of cameras, each consisting of a long-focus camera (LFC) and a short-focus camera (SFC), located face-to-face on each side of a river. The SFC, i.e., wide-angle-lens camera, is used for ship detection, while the LFC, i.e., tele lens camera, is used for precise ship-height measurement. Different from conventional binoculars, the optical axis of the two LFCs are arranged to be colinear in our setup. The advantage of this configuration is in twofold. First, it is simple and precise to calibrate the measuring apparatus and the system error since the two LFCs are mutually visible to each other. Second, due to its face-to-face configuration across the river, the entire navigation waterway is under constant monitoring without blind spot; hence, the shortcoming of limited field of view (FOV) of tele lens is overcome with conventional parallel optical axis stereo vision setup. In this work, the detailed error analysis was performed and in-field experiments were well designed. The experimental data matched very well with the theoretical prediction. The proposed system can achieve a ship-height measuring error below 0.1 m for a distance of 1.46 km.

Trends and Variability in Flood Magnitude: A Case Study of the Floods in the Qilian Mountains, Northwest China

Analyzing trends in flood magnitude changes, and their underlying causes, under climate change, is a key challenge for the effective management of water resources in arid and semi-arid regions, particularly for inland rivers originating in the Qilian Mountains (QMs). Sen’s slope estimator and the Mann–Kendall test were used to investigate the spatial and temporal trends in flood magnitude, based on the annual maximum peak discharge (AMPD) and Peaks Over Threshold magnitude (POT3M) flood series, of twelve typical rivers, from 1970 to 2021. The results showed that, in the AMPD series, 42% of the rivers had significantly decreasing trends, while 8% had significantly increasing trends; in the POT3M series, 25% of the rivers had significantly decreasing trends, while 8% had significantly increasing trends. The regional differences in the QMs from east to west were that, rivers in the eastern region (e.g., Gulang, Zamu, and Xiying rivers) showed significantly decreasing trends in the AMPD and POT3M series; most rivers in the central region had non-significant trends, while the Shule river in the western region showed a significantly increasing trend. Temperatures and precipitation showed a fluctuating increasing trend after 1987, which were the main factors contributing to the change in flood magnitude trends of the AMPD and POT3M flood series in the QMs. Regional differences in precipitation, precipitation intensity, and the ratio of glacial meltwater in the eastern, central and western regions, resulted in the differences in flood magnitude trends between the east and west.

Vertical Distribution and Source Tracking Analysis of Bacteria Composition and Nitrogen Metabolism Function of a Typical Urban Inland River

Microorganisms play an important role in the urban river nitrogen cycle. Due to the three-dimensional fluidity of river water, it is necessary to clarify the vertical distribution of community composition and nitrogen metabolism functions of microorganisms and discover how hydrodynamic factors influence microorganism sources and community composition. Based on 16S rRNA high-throughput sequencing technology, the bacteria community composition and nitrogen metabolism function of water and sediment in the North Canal at Tongzhou District Beijing City were analyzed. The effect of environmental and hydrodynamic factors on community composition and sources were studied. The results showed that the α diversity of sediment was significantly higher than that of water. Proteobacteria was the most abundant phylum, which accounted for 54.72% and 32.36% in water and sediment, respectively. Functional prediction conducted using PICRUSt2 showed that the studied North Canal had an abundance of nitrogen metabolism ability, and 47 genes related to the nitrogen cycle were obtained. Water and sediment microorganisms had a similar distribution of nitrogen metabolism functions. The copy number of genes involved with denitrification, nitrogen assimilation, and dissimilation-reduction were high, whereas the abundance of genes related to biological nitrogen fixation and nitrification were relatively low. Source tracking analysis showed that bacteria in the water that originated from upstream, neighboring sides, and sediment were 60.05%, 37.93%, and 1.05%, respectively. The amounts of bacteria in sediment that migrated from upstream, neighboring sides, and water were 50.16%, 45.55%, and 1.55%, respectively. Environmental factors, hydrodynamic conditions, and their interactions explained water bacteria community composition for 44.22%, 3.21%, and 15.60%, respectively. For sediment bacteria, the degree of explanation was 13.05%, 1.56%, and 8.51%, respectively. This indicated that environmental factors and hydrodynamic factors controlled the community composition and nitrogen cycle functions together.

A Function-Oriented Electronic and Electrical Architecture of Remote Control Ship on Inland River: Design, Verification, and Evaluation

The remote control is an important function of intelligent ships. In this article, first, the functions and communication requirements of remote control ships are sorted out based on the “Rules for Intelligent Ships (2020)” issued by the China Classification Society (CCS). Second, a domain controller-based electronic and electrical architecture (EEA) for inland remote control ships is proposed. The functional domain of the ship is divided, combined with the physical layout of the ship, into the perception domain, communication domain, motion control domain, marine bridge domain, deck domain, cargo management domain, and cabin domain. Third, the real-time network communication system and the central gateway controller are designed, and the efficient information interaction between domain controllers is realized through a service-oriented communication architecture. The simulation experiment shows that the designed domain controller architecture and communication network can meet the information interaction requirements of the ship. Compared with the traditional distributed architecture, the ship EEA based on the domain controller has apparent advantages in system cost, system redundancy, functional load distribution, architecture scalability, communication load distribution, and information security and can give a design reference for inland remote control ships.

Evaluation of GPM and TRMM and Their Capabilities for Capturing Solid and Light Precipitations in the Headwater Basin of the Heihe River

Obtaining accurate precipitation data in mountainous regions is important but challenging. In ungauged areas, remotely sensed precipitation products are useful supplements and alternatives to measured precipitation products. However, their ability to detect solid precipitation and light precipitation in mountain areas is still unclear. The primary objective of this study is to evaluate two satellite precipitation products, Global Precipitation Measurement (GPM) and Tropical Precipitation Measuring Mission (TRMM), in the headwaters of an inland river on the northeastern Tibetan Plateau (the Heihe river basin), with a specific focus on their performance regarding light precipitation and solid precipitation. The achieved results reveal that both GPM and TRMM perform poorly over the Heihe river basin, with low Correlation Coefficient value and Critical Success Index value, particularly in winter. Based on the coupled Time-Variant Gain Model-Degree Day Factor Model (TVGM-DDF) initiated in this paper, the GPM is more applicable in terms of running hydrological models. With the aim of detecting solid precipitation, the GPM is more capable of detecting solid precipitation but still unsatisfactory at two stations. In the case of light precipitation, both products underestimate light precipitation. In general, the performance of the two products in the Heihe river basin is not satisfactory and should be enhanced in upcoming explorations. This study provides a strong foundation for choosing alternate precipitation data for related research in the mountain basin.

Anthropogenic activities control the source dynamics of sediment organic carbon in the lower reach of an inland river

Sediment organic carbon (SeOC) sources with rich information can be used as a "historical archive" reflecting anthropogenic activities in the catchment, which is crucial to carbon management in the watershed. Anthropogenic activities and hydrodynamic conditions significantly influence the river environment and are reflected by the SeOC sources. However, the key drivers of the SeOC source dynamics are ambiguous, which restricts the behavior of regulating the carbon output of the basin. In this study, sediment cores from the lower reach of an inland river were selected to quantify the SeOC sources based on a centennial scale. A partial least squares path model was used to establish the relationship between anthropogenic activities and hydrological conditions with the SeOC sources. Findings showed that the exogenous advantage of SeOC composition was gradually significant (early period: 54.3%; middle period: 81%; later period: 82%) from the bottom layer to the surface layer of the sediments in the lower reach of the Xiangjiang River. Factors related to anthropogenic activities controlled the external input of SeOC (δ13C: r∂ = -0.94, P < 0.001; δ15N: r∂ = -0.66, P < 0.001). Different anthropogenic activities performed different effects. Land use change aggravated soil erosion and brought more terrestrial organic carbon to the downstream. The variation of grassland carbon input was the most obvious (from 33.6% to 18.4%). In contrast, the reservoir construction intercepted upstream sediments, which might have been the main reason for the slow growth of terrestrial organic carbon input in the downstream in the later period. This study provides a specific grafting for the SeOC records - source changes - anthropogenic activities in the lower reach of the river, which provides scientific basis for watershed carbon management.

A Novel Intelligent Detection Algorithm of Aids to Navigation Based on Improved YOLOv4

Aiming at the problem of high-precision detection of AtoN (Aids to Navigation, AtoN) in the complex inland river environment, in the absence of sufficient AtoN image types to train classifiers, this paper proposes an automatic AtoN detection algorithm Aids-to-Navigation-YOLOv4 (AN-YOLOv4) based on improved YOLOv4 (You Only Look Once, Yolo). Firstly, aiming at the problem of an insufficient number of existing AtoN datasets, the Deep Convolutional Generative Adversarial Networks (DCGAN) is used to expand and enhance the AtoN image dataset. Then, aiming at the problem of small target recognition accuracy, the image pyramid is used to multi-scale zoom the dataset. Finally, the K-means clustering algorithm is used to correct the candidate box of AN-YOLOv4. The test on the test dataset shows that the improvement effect of AN-YOLOv4 is obvious. The accuracy rate of small targets is 92%, and the average accuracy (mAP) of eight different types of AtoN is 92%, which is 14% and 13% higher than the original YOLOv4, respectively. This research has important theoretical significance and reference value for the intelligent perception of the navigation environment under the intelligent shipping system.

Mitigation Effect of Dense “Water Network” on Heavy PM2.5 Pollution: A Case Model of the Twain-Hu Basin, Central China

The influence of the underlying surface on the atmospheric environment over rivers and lakes is not fully understood. To improve our understanding, this study targeted the Twain-Hu Basin (THB) in central China, with a unique underlying surface comprising a dense "water network" over rivers and lakes. In this study, the Weather Research and Forecasting Model with Chemistry (WRF-Chem) was used to simulate the impact of this dense "water network" on a wintertime heavy PM2.5 pollution event in the THB. On this basis, the regulating effects of density and area of the lake groups, with centralized big lakes (CBLs) and discrete small lakes (DSLs), on PM2.5 concentrations over the underlying surface of the dense "water network" in the THB were clarified, and the relative contributions of thermal factors and water vapor factors in the atmospheric boundary layer to the variation of PM2.5 concentrations were evaluated. The results show that the underlying surface of dense "water networks" in the THB generally decreases the PM2.5 concentrations, but the influences of different lake-group types are not uniform in spatial distribution. The CBLs can reduce the PM2.5 concentrations over the lake and its surroundings by 4.90-17.68% during the day and night. The ability of DSLs in reducing PM2.5 pollution is relatively weak, with the reversed contribution between -5.63% and 1.56%. Thermal factors and water vapor-related factors are the key meteorological drivers affecting the variation of PM2.5 concentrations over the underlying surface of dense "water networks". The warming and humidification effects of such underlying surfaces contribute positively and negatively to the "purification" of air pollution, respectively. The relative contributions of thermal factors and water vapor-related factors are 52.48% and 43.91% for CBLs and 65.96% and 27.31% for DSLs, respectively. The "purification" effect of the underlying surface with a dense "water network" in the THB on regional air pollution highlights the importance of environmental protection of inland rivers and lakes in regional environmental governance. In further studies on the atmospheric environment, long-term studies are necessary, including fine measurements in terms of meteorology and the environment and more comprehensive simulations under different scenarios.

Spatial variation patterns of vegetation and soil physicochemical properties of a typical inland riverscape on the Mongolian plateau

The spatial distribution and heterogeneity of soil and vegetation, as the root of the maintenance of ecosystem services in the riparian zone, play a decisive role in the ecological functions of the riverscape. In this study, a field survey of wetland plant communities and soil sampling were conducted in both longitudinal and lateral dimensions from the perspective of the riverscape of the Ulgai River, a typical inland river on the Mongolian Plateau. The diversity of wetland plant communities, soil physicochemical properties, and the correlations between them were systematically analyzed. The results showed that a total of 87 species belonging to 65 genera and 24 families of plants were present, with Asteraceae, Poaceae, and Cyperaceae as the main families. The plant composition and species diversity in the riparian zone at different dimensions showed obvious spatial patterns of succession. Although the correlation coefficient and significance of the physicochemical properties of river length and river width in the study area were different, most correlations remained consistent, among which soil moisture, soil pH, and total carbon were correlated with many physicochemical factors. The soil ammonium and nitrate nitrogen along the river length direction and electrical conductivity and organic carbon content along the river width direction were the main limiting factors affecting the diversity and distribution of plant species in the riparian zone based on the redundancy analysis. This study provides a theoretical basis for the continuous improvement of the current soil quality and the restoration of the degraded wetland ecosystems of inland rivers in arid and semi-arid regions, as well as a new perspective for the study of riverscape ecology.

Potential effects of oasis expansion on ecosystem service value in a typical inland river basin of northwest China.

To satisfy an increasing need for living space and food while preserving ecosystem services remains one of today's biggest challenges. Oases in arid areas have gradually become the main sources for new cultivated land, affecting the supply and transmission of ecosystem services. Yet, little assessment on predicting the effects of oasis expansion on ecosystem service value (ESV) has been available to guide policy makers and ecologists. Here we addressed the connections between oasis expansion and ESV in the middle reaches of the Heihe River Basin in northwest China by linking the Logistic-CA-Markov model and the benefit transfer method. The results showed that the oasis was expected to expand by 419.02 km2 from 2015 to 2029, with the area of farmland and construction land increasing by 18.87% and 39.05%, respectively. With oasis expansion, the total ESV was expected to increase by 104.25 million RMB from 2015 to 2029. However, oasis expansion encroaches on vegetation, resulting in decline of the values of climate regulation, waste treatment, and biodiversity protection. This study will provide a reference for decision-making in trade-offs involved in land management.

Quantifying spatiotemporal patterns and influencing factors of urban shrinkage in China within a multidimensional framework:A case study of the Yangtze River Economic Belt

Explorations of urban shrinkage at regional scales have received much attention around the world. The Yangtze River Economic Belt (YREB), one of the most influential inland river economic belts in the world, has not yet received sufficient attention to its urban shrinkage issue. This study explored the spatiotemporal patterns and influencing factors of shrinking cities in the YREB within a multidimensional framework, including population, economy, and space. The results showed that the degree of demographic, economic, and spatial shrinkage is mainly slight or moderate in the YREB. In terms of shrinking duration, these shrinking cities mainly undergo temporary shrinkage. The majority of cities undergo shrinkage in only one dimension, accounting for more than 62% of all shrinking cities. The spatial heterogeneity of shrinking cities mainly comes from within reaches and urban agglomerations, while there is little difference in shrinkage between reaches and between urban agglomerations. Fixed asset investment, total social consumption, the industrial output value above the scale, and the built-up area had significant impacts on the population agglomeration, economic agglomeration, and public service accessibility of multidimensionally shrinking cities. The spatiotemporal heterogeneity and dynamics of shrinkage suggest that a multi-level management system should be constructed to cope with urban shrinkage in different regions of the YREB. This study can provide a reference for narrowing the developmental imbalance for the YREB and contributes to promoting the research progress of urban shrinkage at regional scales.

Effects of precipitation changes and land-use alteration on streamflow: A comparative analysis from two adjacent catchments in the Qilian Mountains, arid northwestern China

Comparative analysis of the impacts of precipitation and land use on streamflow from adjacent catchments is critical to exploring pathways toward water security and sustainable development. In this work, two adjacent catchments (the Mayinghe and Xidahe, abbreviated as MYC and XDC, respectively) in northwestern China were selected to compare the impacts of precipitation change and land use alteration on streamflow change during 1956–2019 using field observation streamflow data and satellite data. An opposite trend of streamflow was found for the two catchments from 1956 to 2019: the streamflow decreased significantly in the MYC (-0.63 × 107m3/10a, p &amp;lt; 0.05), while it increased in the XDC (0.71 × 107m3/10a, p &amp;lt; 0.05). Land conversion dominated the streamflow reduction in the MYC, with a contribution of about 68.3%. In the XDC, precipitation was confirmed to be the major factor driving the increase in streamflow. The streamflow for farmland irrigation reached 27.97 × 104 m3/km2 in the MYC, which was the leading factor of streamflow reduction in the basin. The findings obtained from this work can shed light on the quantitative understanding of streamflow changes in small catchments and offer a scientific basis for sustainable water management in other inland river basins.