In the mountainous headwaters of the Colorado River episodic dust deposition from adjacent arid and disturbed landscapes darkens snow and accelerates snowmelt, impacting basin hydrology. Patterns and impacts across the heterogenous landscape cannot be inferred from current in situ observations. To fill this gap daily remotely sensed retrievals of radiative forcing and contribution to melt were analyzed over the MODIS period of record (2001-2023) to quantify spatiotemporal impacts of snow darkening. Each season radiative forcing magnitudes were lowest in early spring and intensified as snowmelt progressed, with interannual variability in timing and magnitude of peak impact. Over the full record, radiative forcing was elevated in the first decade relative to the last decade. Snowmelt was accelerated in all years and impacts were most intense in the central to southern headwaters. The spatiotemporal patterns motivate further study to understand controls on variability and related perturbations to snow water resources.

Non-technical summary To address the issues of declining groundwater levels and the degradation of soil ecological functions caused by open-pit coal mining in China. Based on theoretical analysis, laboratory experiments, on-site monitoring, mathematical modeling, and other means, the concept of coal ecological protection mining of 'damage reduction mining, three-dimensional protection, systematic restoration' is proposed. The mining concept has achieved remarkable ecological restoration effects, leading the scientific and technological progress of safe, efficient and green mining in open-pit coal mines. Technical summary The mechanism of damage propagation among 'rock-soil-water' ecological elements in open-pit coal mining was revealed. Adopting comprehensive damage-reducing mining technology throughout the entire stripping process, mining and drainage, shengli open-pit coal mine has doubled its production capacity, and reduced the land excavation and damage by 60 mu/year, reduced the mining area by 1,128 mu, and raised the groundwater level by 2.6-6 m, and the ecological restoration of the drainage field was advanced by more than 1 year. Adopting the three-dimensional water storage technology involves underground reservoirs, aquifer reconstruction, and near-surface distributed water storage units, baorixile open-pit mine has built the world's first open-pit underground water reservoir, with a water storage capacity of 1.22 million m(3), and the speed of groundwater level restoration has been increased by more than 70%. By adopting the systematic restoration technology of geomorphology-soil-vegetation in the discharge site, the soil water content in the demonstration area has been increased by 52%, the survival rate of plants has been increased by 34%, and the vegetation coverage has been increased by more than 40%. Social media summary Damage-reducing mining and systematic ecological restoration in open-pit coal mining are essential for the safe, efficient and green development of coal.

Mining can greatly affect water quality in nearby areas, especially when mines are abandoned and lead to contamination from tailings and drainage. This study examines the impact of the abandoned Ze & iuml;da lead mine on water sources in the Upper Moulouya region of northwestern Morocco. We aimed to evaluate water quality, understand geochemical processes, and determine the suitability of water for drinking and irrigation. In summer 2021, 21 water samples were collected from rivers, dams, groundwater, and quarry lakes. We analyzed 18 physicochemical and metallic parameters, finding significant variations in ion concentrations. The main ions were ranked as Na+ > Mg2+ > Ca2+ > K+ and HCO3- > Cl- > SO42- > NO3-. Metal concentrations followed the order Zn > Cu > Pb > As > Cd. The Drinking Water Quality Index (DWQI) showed that 95% of the samples were not suitable for drinking. Similarly, the Irrigation Water Quality Indexes (IWQIs) indicated that quarry lakes were unsuitable for irrigation, while groundwater met acceptable criteria. Over 70% of the samples showed no significant metal contamination based on the Heavy Metal Evaluation Index (HEI) and Heavy Metal Pollution Index (HPI). The data suggest that water-rock interactions are the main drivers of hydrochemical changes, with processes like calcite, dolomite, otavite, and cerussite precipitation, as well as the weathering of minerals like halite, starkeyite, and sylvite. To protect water quality and prevent environmental damage, ongoing monitoring and appropriate measures are recommended for the Ze & iuml;da mining area.

Glacial changes are crucial to regional water resources and ecosystems in the Sawir Mountains. However, glacial changes, including the mass balance and glacial meltwater of the Sawir Mountains, have sparsely been reported. Three model calibration strategies were constructed including a regression model based on albedo and in-situ mass balance of Muz Taw Glacier (A-Ms), regression model based on albedo and geodetic mass balance of valley, cirque, and hanging glaciers (A-Mr), and degree-day model (DDM) to obtain a reliable glacier mass balance in the Sawir Mountains and provide the latest understanding in the contribution of glacial meltwater runoff to regional water resources. The results indicated that the glacial albedo reduction was significant from 2000 to 2020 for the entire Sawir Mountains, with a rate of 0.015 (10a)- 1, and the spatial pattern was higher in the east compared to the west. Second, the three strategies all indicated that the glacier mass balance has been continuously negative during the past 20 periods, and the average annual glacier mass balance was -1.01 m w.e. Third, the average annual glacial meltwater runoff in the Sawir Mountains from 2000 to 2020 was 22 x 106 m3, and its

This study uses a new dataset on gauge locations and catchments to assess the impact of 21st-century climate change on the hydrology of 221 high-mountain catchments in Central Asia. A steady-state stochastic soil moisture water balance model was employed to project changes in runoff and evaporation for 2011-2040, 2041-2070, and 2071-2100, compared to the baseline period of 1979-2011. Baseline climate data were sourced from CHELSA V21 climatology, providing daily temperature and precipitation for each subcatchment. Future projections used bias-corrected outputs from four General Circulation Models under four pathways/scenarios (SSP1 RCP 2.6, SSP2 RCP 4.5, SSP3 RCP 7.0, SSP5 RCP 8.5). Global datasets informed soil parameter distribution, and glacier ablation data were integrated to refine discharge modeling and validated against long-term catchment discharge data. The atmospheric models predict an increase in median precipitation between 5.5% to 10.1% and a rise in median temperatures by 1.9 degrees C to 5.6 degrees C by the end of the 21st century, depending on the scenario and relative to the baseline. Hydrological model projections for this period indicate increases in actual evaporation between 7.3% to 17.4% and changes in discharge between + 1.1% to -2.7% for the SSP1 RCP 2.6 and SSP5 RCP 8.5 scenarios, respectively. Under the most extreme climate scenario (SSP5-8.5), discharge increases of 3.8% and 5.0% are anticipated during the first and second future periods, followed by a decrease of -2.7% in the third period. Significant glacier wastage is expected in lower-lying runoff zones, with overall discharge reductions in parts of the Tien Shan, including the Naryn catchment. Conversely, high-elevation areas in the Gissar-Alay and Pamir mountains are projected to experience discharge increases, driven by enhanced glacier ablation and delayed peak water, among other things. Shifts in precipitation patterns suggest more extreme but less frequent events, potentially altering the hydroclimate risk landscape in the region. Our findings highlight varied hydrological responses to climate change throughout high-mountain Central Asia. These insights inform strategies for effective and sustainable water management at the national and transboundary levels and help guide local stakeholders.

Agricultural irrigation is a significant contributor to freshwater consumption. However, the current irrigation systems used in the field are not efficient. They rely mainly on soil moisture sensors and the experience of growers but do not account for future soil moisture loss. Predicting soil moisture loss is challenging because it is influenced by numerous factors, including soil texture, weather conditions, and plant characteristics. This article proposes a solution to improve irrigation efficiency, which is called DRLIC (deep reinforcement learning for irrigation control). DRLIC is a sophisticated irrigation system that uses deep reinforcement learning (DRL) to optimize its performance. The system employs a neural network, known as the DRL control agent, which learns an optimal control policy that considers both the current soil moisture measurement and the future soil moisture loss. We introduce an irrigation reward function that enables our control agent to learn from previous experiences. However, there may be instances in which the output of our DRL control agent is unsafe, such as irrigating too much or too little. To avoid damaging the health of the plants, we implement a safety mechanism that employs a soil moisture predictor to estimate the performance of each action. If the predicted outcome is deemed unsafe, we perform a relatively conservative action instead. To demonstrate the real-world application of our approach, we develop an irrigation system that comprises sprinklers, sensing and control nodes, and a wireless network. We evaluate the performance of DRLIC by deploying it in a test-bed consisting of six almond trees. During a 15-day in-field experiment, we compare the water consumption of DRLIC with a widely used irrigation scheme. Our results indicate that DRLIC outperforms the traditional irrigation method by achieving water savings of up to 9.52%.

Although climate change has convincingly been linked to the evolution of human civilization on different temporal scales, its role in influencing the spatial patterns of ancient civilizations has rarely been investigated. The northward shift of the ancient Silk Road (SR) route from the Tarim Basin (TB) to the Junggar Basin during -420-850 CE provides the opportunity to investigate the relationship between climate change and the spatial evolution of human societies. Here, we use a new high-resolution chironomidbased temperature reconstruction from arid China, combined with hydroclimatic and historical datasets, to assess the possible effects of climate fluctuations on the shift of the ancient SR route. We found that a cooling/drying climate in the TB triggered the SR route shift during -420-600 CE. However, a warming/ wetting climate during -600-850 CE did not inhibit this shift, but instead promoted it, because of the favorable climate-induced geopolitical conflicts between the Tubo Kingdom and the Tang Dynasty in the TB. Our findings reveal two distinct ways in which climate change drove the spatial evolution of human civilization, and they demonstrate the flexibility of societal responses to climate change. (c) 2024 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.

China's Northwest Arid Region (NAR), with dry and cold climate conditions and glaciers widely developed in the high mountains, provides vital water resources for Asia. The consecutive cold, warm, dry and wet days have much higher impacts on the water cycle process in this region than extreme temperature and precipitation events with short durations but high intensities. Parametric and nonparametric trend analysis methods widely used in climatology and hydrology are employed to identify the temporal and spatial features of the changes in the consecutive cold, warm, dry and wet days in the NAR based on China's 0.5 degrees x 0.5 degrees meteorological grid datasets of daily temperature and precipitation from 1961 to 2018. This study found that (1) the consecutive cold days (Cold Spell Duration Indicator, CSDI), and the consecutive dry days (CDD) decreased, while the consecutive warm days (Warm Spell Duration Indicator, WSDI), and the consecutive wet days (CWD) increased from 1961 to 2018, (2) and the eastern Kunlun Mountains were the hot spots where all of these consecutive climate indices changed significantly, (3) and the changes in these consecutive climate indices were highly correlated with the rise in the Global Mean Land/Ocean Temperature Index. The results indicated that winters tended to warmer and dryer and summer became hotter and wetter during 1961-2018 in the NAR under the global warming, which can lead to the sustained glacier retreat and the increase in summer runoff in this region, and the eastern Kunlun Mountains are the area where could face high risks of water scarcity and floods if the changes in these climate indices continue in the future. Given the vulnerability of the socio-economic systems in the NAR to a water shortage and floods, it is most crucial to improve the strategies of water resources management, disaster prevention and risk management for this region under climate change.

The global concern about water quality in coal mining operations is a significant issue. It presents detrimental water-related threats, including pollution, acid mine drainage, and habitat destruction. In this study, an attempt has been made to evaluate the water quality for domestic, irrigation and industrial purposes in the coal mining province of Mahan catchment area, with a particular focus on the impact of coal mining activities. 50 samples from pre-monsoon season of 2018, collected from dug well, tube well, mine water and river water were analyzed. The findings indicate that water in the study area exhibits acidic characteristics, with pH values below the desirable range for drinking water. Elevated electrical conductivity, total dissolved solids, sulphate, total hardness and chloride concentrations are observed, particularly around core mining regions. For irrigation suitability, the study reveals that most of the samples are suitable, based on parameters such as sodium percent-age (Na%) sodium adsorption ratio (SAR), magnesium hazard (MH), Kelly's index (KI), permea-bility index (PI), and residual sodium carbonate (RSC). However, majority of the samples collected from core mines show an elevated range of Na% (>80), SAR (>60), MH (>50), KI (>1), PI (>100), RSC (>2.5) and PS (>5) indicating potential soil permeability issues and crop damage, which restrict its suitability for agricultural use. Furthermore, the assessment of water for industrial suitability by analyzing the scaling and corrosion indices, such as the Langelier index (LI), aggressive index (AI), Ryznar index (RI), Puckorius index (PI), and corrosivity ratio (CR) highlights the presence of a corrosive tendency in majority of the water samples, particularly in the mining areas.

Study region: Upper Yellow River Basin (UYRB), China. Study focus: We provide a comprehensive overview of the changes in the natural social binary water cycle system in the UYRB from the perspectives of the atmosphere, hydrosphere, cryosphere, biosphere, and human society by summarizing previous research results. New hydrological insight for the region: Since the 1980s, the continuous temperature rise led to permafrost thawing, resulting in a decrease in runoff and an increase in groundwater in the UYRB. The ecological protection and high-quality development of human society continuously increase the demand for water resources. Especially the runoff of the river in the human gathering area has significantly decreased and there has been an overexploitation of groundwater, resulting in a serious shortage of water resources. The future water supply and demand situation in the UYRB will be more severe. However, the current understanding of the natural social binary water cycle in the Upper Yellow River Basin is still insufficient, which seriously limits the high-quality development of human society in the UYRB. Among them, some erroneous conclusions can even provide misleading information for policy-making and cause serious manpower and resources loss. Natural social binary water cycle is still in initial stage in the UYRB, that is reflected in a lot of contradictions and shortcomings in past research. We propose four feasible research directions to comprehensively promote hydrometeorological research, providing effective guidance for the formulation of high-quality development policies in the UYRB.