Nearly 1 100 fissures have formed on the Hebei Plain in China. Within the Yellow River-Qinghe River-Zhanghe River shallow buried paleochannel band on the plain, 93 ground fissures controlled by paleochannels have developed, of which the Wuyi-Fuping ground fissure is a typical paleochannel-controlled fissure located in Hengshui, Hebei Province, with a total length of 3 km, a dominant strike of NE78 degrees, and nearly upright in the shallow layer. The surface damage observed in this fissure primarily manifests as beaded pits, and its activity shows distinct segmentation characteristics. On the trench profiles, the offset distance of shallow layers remains consistently around 20 cm within the depth range of 0 to -3 m. An evident flexure is observed in the strata at depths ranging from -4.5 to -7 m. The drilling profile reveals that there is an absence of dislocations in the deeper strata. Nonetheless, the shallow seismic physical profiles unveil the presence of underlying faults beneath the study area, underscoring the intricate formation process and genesis mechanism of the Wuyi-Fuping ground fissure. Firstly, the formation and evolution of the Qingling River's paleochannel were shaped by the actions of fault blocks and underlying faults. The interplay of the regional stress field, fault block movement, and fault activity played pivotal roles in driving the development of this paleochannel. Secondly, the paleochannel exerts a controlling influence on the development location and severity of the fissure. During pumping, the confined aquifer within the paleochannel undergoes water loss and compression, resulting in the formation of a surface subsidence funnel. When the tensile stress surpasses the soil's tensile strength at the funnel's edge, the soil fractures give rise to a ground fissure. Finally, large amounts of surface water generated by heavy rainfall and irrigation can cause existing hidden ground fissures to rupture, emerge, and expand. This paper provides a heretofore generally unknown example, promotes research on the mechanisms of paleochannel-controlled fissures, and has guiding significance for disaster prevention and reduction in this area.

The extensive use of pesticides has led to the contamination of natural resources, sometimes causing significant and irreversible damage to the environment and human health. Even though the use of many pesticides is banned, these compounds are still being found in rivers worldwide. In this review, 205 documents have been selected to provide an overview of pesticide contamination in rivers over the last 10 years (2014-2024). After these documents were examined, information of 47 river systems was organized according to the types of pesticides most frequently detected, including organochloride, organophosphorus, and pyrethroid compounds. A total of 156 compounds were classified, showing that 46% of these rivers contain organochlorine compounds, while 40% exhibit organophosphorus pesticides. Aldrin, hexachlorocyclohexane, and endosulfan were the predominant organochlorine pesticides with concentration values between 0.4 and 37 x 105 ng L-1. Chlorpyrifos, malathion, and diazinon were the main organophosphorus pesticides with concentrations between 1 and 11 x 105 ng L-1. Comparing the pesticide concentrations with standard guidelines, we found that the Ganga River in India (90 ng L-1), the Owan and Okura Rivers in Nigeria (210 and 9 x 103 ng L-1), and the Dong Nai River in Vietnam (68 ng L-1) exceed the permissible levels of aldrin (30 ng L-1).

A clear understanding of the changes of water resources under the background of environmental changes is of great significance for scientific management and utilization of water resources in China. This study systematically analyzed the spatial-temporal variations of surface water resources in China since 2000. Water vulnerability in current (2010s) and its trends from 2000 to late-2010s in different regions of China were also summarized. In addition, the correspondingly adaptive measures to counter regional risks to water resources were proposed. We concluded that the runoff of major rivers had been decreasing in eastern China and increasing in western China during 2000-2018. In the arid area of Northwest China, the alpine runoff has shown an overall upward trend since the late-1990s/early-2000s, with a 10%-25% increase caused by the increase of glacial meltwater and precipitation. While the runoff of each hydrological station in the 2000s-2010s was 34.7% lower than that in the 1950s-2010s on average. The increases in precipitation and glacial meltwater with global warming caused a rapid expansion of lakes in the Qinghai-Tibet Plateau and Xinjiang, thus leading to an increase in total area and water quantity of lakes in China from 1995 to 2015. The mean contribution rates of climate change and human activity to runoff change in river basins of China were 53.5% and 46.5%, respectively, during the period of 2000-2010s. The driving factor of runoff change in many river basins has gradually changed from climate change (1950s-2000) to human activity (2000-2018). During 2000-2018, the contributions of human activities to runoff change were 50%-80% in major rivers of eastern China. The vulnerability in most areas of Northwest China and North China is generally high, with the vulnerability index greater than 0.6. Comparatively, in Northeast, East, South, and Central China, it is lower or not vulnerable. In Southwest China, the vulnerability varies greatly with Yunnan and Sichuan relatively low while Chongqing and Guizhou relatively high. The precipitation increase, the application of water-saving technology, the establishment of flood control and drought relief engineering facilities, and the introduction of relevant policies and measures have helped to gradually reduce the vulnerability of water resources in most areas of North and Northwest China (except Xinjiang) from 2000 to 2010s. Water vulnerability has been increasing in southern China, caused by climate change and the development of industry and agriculture, which increases water resource exposure since 2000. Based on the typical risk factors and vulnerability characteristics of water resources in different regions, this study proposed some targeted adaptive measures correspondingly so as to scientifically deal with the problems of surface water resources in China.

The Qinghai-Tibet Plateau is rich in water resources with numerous lakes, rivers, and glaciers, and, as a source of many rivers in Central Asia, it is known as the Asian Water Tower. Under global climate change, it is critical to understand the current influencing factors on surface water area in this region. Although there are numerous studies on surface water mapping, they are still limited by temporal/spatial resolution and record length. Moreover, the complicated topographic condition makes it challenging to map the surface water accurately. Here, we proposed an automatic two-step annual surface water classification framework using long time-series Landsat images and topographic information based on the Google Earth Engine (GEE) platform. The results showed that the producer accuracy (PA) and user accuracy (UA) of the surface water map in the Qinghai-Tibet Plateau in 2020 were 99% and 90%, respectively, and the Kappa coefficient reached 0.87. Our dataset showed high consistency with high-resolution images, indicating that the proposed large-scale water mapping method has great application potential. Furthermore, a new annual surface water area dataset on the Qinghai-Tibet Plateau from 2000 to 2020 was generated, and its relationship with climate, vegetation, permafrost, and glacier factors was explored. We found that the mean surface water area was about 59 481 km(2), and there was a significant increasing trend (=322 km(2)/year, p < 0.01) during 2000-2020 in the plateau. Greening, warming, and wetting climate conditions contributed to the increase of surface water area. Active layer thickness and permafrost types may be the most related to the decrease of surface water area. This study provides important information for ecological assessment and protection of the plateau and promotes the implementation of sustainable development goals related to surface water resources.

On the Arctic Coastal Plain (ACP) in northern Alaska (USA), permafrost and abundant surface-water storage define watershed hydrological processes. In the last decades, the ACP landscape experienced extreme climate events and increased lake water withdrawal (LWW) for infrastructure construction, primarily ice roads and industrial operations. However, their potential (combined) effects on streamflow are relatively underexplored. Here, we applied the process-based, spatially distributed hydrological and thermal Water Balance Simulation Model (10 m spatial resolution) to the 30 km(2) Crea Creek watershed located on the ACP. The impacts of documented seasonal climate extremes and LWW were evaluated on seasonal runoff (May-August), including minimum 7-day mean flow (MQ7), the recovery time of MQ7 to pre-perturbation conditions, and the duration of streamflow conditions that prevents fish passage. Low-rainfall scenarios (21% of normal, one to three summers in a row) caused a larger reduction in MQ7 (-56% to -69%) than LWW alone (-44% to -58%). Decadal-long consecutive LWW under average climate conditions resulted in a new equilibrium in low flow and seasonal runoff after 3 years that included a disconnected stream network, a reduced watershed contributing area (54% of total watershed area), and limited fish passage of 20 days (vs. 6 days under control conditions) throughout summer. Our results highlight that, even under current average climatic conditions, LWW is not offset by same-year snowmelt as currently assumed in land management regulations. Effective land management would therefore benefit from considering the combined impact of climate change and industrial LWWs.

Groundwater-surface water (GW-SW) interaction, as a key component in the cold region hydrologic cycle, is extremely sensitive to seasonal and climate change. Specifically, the dynamic change of snow cover and frozen soil bring additional challenges in observing and simulating hydrologic processes under GW-SW interactions in cold regions. Integrated hydrologic models are promising tools to simulate such complex processes and study the system behaviours as well as its responses to perturbations. The cold region integrated hydrologic models should be physically representative and fully considering the thermal-hydrologic processes under snow cover variations, freeze-thaw cycles in frozen soils and GW-SW interactions. Benchmarking and integration with scarce field observations are also critical in developing cold region integrated hydrologic models. This review summarizes the current status of hydrologic models suitable for cold environment, including distributed hydrologic models, cryo-hydrogeologic models, and fully-coupled cold region GW-SW models, with a specific focus on their concepts, numerical methods, benchmarking, and applications across scales. The current research can provide implications for cold region hydrologic model development and advance our understanding of altered environments in cold regions disturbed by climate change, such as permafrost degradation, early snow melt and water shortage.

The hydrology of the Third Pole, Asia's freshwater tower, has shown considerable sensitivity to the impacts of climate change and human interventions, which affect the headwaters of many rivers that originate therein. For example, the Yangtze River has its basin (YRB) experiencing wetness of terrestrial water storage (TWS), whose rainfall seems to be the primary source as inferred from the previous studies. Consequently, it is crucial to understand the contributions of each TWS's sub-domain - i.e., groundwater (GWS); total water content (TWC) stored as soil moisture, ice/snow, and canopy; and the surface water (SWS) storages - on YRB's wetness. Hence, SWS, from altimetry and imagery satellites, and TWC, from Global Land Data Assimilation System, are inverted considering the same basis function as for TWS from the Gravity Recovery and Climate Experiment, which account for the differences in the resolutions inherent in each product. Furthermore, a tie-in signal approach is used to fit the temporal patterns of GWS, TWC, and SWS to TWS (i.e., the observations). Results show improvements in the reconstructed GWS series concerning standard deviation, correlation coefficient, and Nash-Sutcliffe efficiency of 22%, 27%, and 120%, respectively, regarding the use of the TWS-budget equation. The reconstructed time series of GWS, TWC, and SWS present an increase of 1.76, 2.69, and 0.14 mm per year (mm/yr) and that YRB loses water stored at its aquifers 55% of the time (regarding 2003-2016 period) based on the quantile function of storage (QFS). The QFS's slope shows that TWS has a fast and small storage potential w.r.t. GWS since inland waters and soil moisture reflect the dryness impacting TWS first. Despite the evidence of an increase of 19.05 mm/yr in annual precipitation, which seems to explain the bulk in TWS, further investigation to characterize controls on TWS memory within YRB is still necessary. (C) 2020 Elsevier B.V. All rights reserved.

Understanding the interaction between groundwater and surface water in permafrost regions is essential to study flood frequencies and river water quality, especially in the high latitude/altitude basins. The application of heat tracing method, based on oscillating streatnbed temperature signals, is a promising geophysical method for identifying and quantifying the interaction between groundwater and surface water. Analytical analysis based on a one-dimensional convective -conductive heat transport equation combined with the fiber-optic distributed temperature sensing method was applied on a stream bed of a mountainous permafrost region in the Yeniugou Basin, located in the upper Heihe River on the northern Tibetan Plateau. The results indicated that low connectivity existed the stream and groundwater in permafrost regions. The interaction between surface water and groundwater increased with the thawing of the active layer. This study demonstrates that the heat tracing method can be applied to study surface water-groundwater interaction over temporal and spatial scales in permafrost regions.

The spatial-temporal changes in terrestrial water storage (TWS) over the Tibetan Plateau (TP) and six selected basins during 2003-2014 were analyzed by applying the Gravity Recovery and Climate Experiment data and the extended Variable Infiltration Capacity-glacier model, including the upstream of Yangtze (UYA), Yellow (UYE), Brahmaputra (UB), and Indus river basins and the Inner TP and the Qaidam Basin. The possible causes of TWS changes were investigated from the perspective of surface water balance and TWS components through multisource data and the Variable Infiltration Capacity-glacier model. There was a strong spatial heterogeneity in changes of Gravity Recovery and Climate Experiment TWS in the TP-with apparent mass accumulation in central and northern TP and a sharp decreasing trend in southern and northwestern TP. The TWS changes in the TP were mostly attributed to variations in precipitation and evapotranspiration from the perspective of land-surface water balance. Precipitation played a dominant role on the TWS accumulation in the UYA and UYE, while evapotranspiration had a more important role than precipitation in TWS depletion in the UB. From the perspective of TWS components, the TWS increase in the UYA and UYE was mainly caused by an increase in soil moisture, whereas the decrease in TWS in the UB was mostly due to glacier mass loss. TWS was accumulating from March through August in southeastern TP while from November to April/May in northwestern TP. The seasonal variations of TWS are highly modulated by the large-scale climate system, atmospheric moisture flux, and precipitation regime over the TP.

The Yukon River Basin, underlain by discontinuous permafrost, has experienced a warming climate over the last century that has altered air temperature, precipitation, and permafrost. We investigated a water chemistry database from 1982 to 2014 for the Yukon River and its major tributary, the Tanana River. Significant increases of Ca, Mg, and Na annual flux were found in both rivers. Additionally, SO4 and P annual flux increased in the Yukon River. No annual trends were observed for dissolved organic carbon (DOC) from 2001 to 2014. In the Yukon River, Mg and SO4 flux increased throughout the year, while some of the most positive trends for Ca, Mg, Na, SO4, and P flux occurred during the fall and winter months. Both rivers exhibited positive monthly DOC flux trends for summer (Yukon River) and winter (Tanana River). These trends suggest increased active layer expansion, weathering, and sulfide oxidation due to permafrost degradation throughout the Yukon River Basin.