The travel time or “age” of groundwater affects catchment responses to hydrologic changes, geochemical reactions, and time lags between management actions and responses at down-gradient streams and wells. Use of atmospheric tracers has facilitated the characterization of groundwater ages, but most wells lack such measurements. This study applied machine learning to predict ages in wells across a large

Spatial downscaling has recently become a crucial process in the regional application of coarse-resolution passive microwave surface soil moisture (SSM) products. Extensive gaps in auxiliary optical/thermal infrared observation data (mainly caused by cloud cover) and gaps in coarse-resolution passive microwave SSM data lead to spatiotemporal discontinuity in downscaled SSM maps, thereby limiting their

Modeling the washoff of pollutants from urban catchments is a difficult task. Although the exponential washoff model has been in use for decades, there is a general lack of data on model parameters and much less is known about how the model parameters are influenced by storm and climate characteristics. This study was done to understand how model parameters vary between different catchments having

The performance criteria have been often used in the hydrological model evaluation or calibration. Since the performance criteria have their own advantages and disadvantages, it is necessary to understand the impact of each performance criterion on the model evaluation or calibration to be used for the purposes of model applications. The Liu Mean Efficiency (LME) was proposed for the design flow estimates

The ecohydrological and biochemical processes responsible for the globally significant stores of carbon in northern peatlands are largely controlled by the soil’s hydrophysical properties, in particular the relationship that soil water tension (ψ) has with soil water content (θ) and hydraulic conductivity (K). Despite the importance, little is known about how these relationships vary between species

With the deep mining of North China-type coalfield, the threat of mixed water source is increasingly serious, and water inrush accidents occur from time to time. Identifying the water inrush dynamic of limestone-mixed water source in high geothermal coal mine is difficult. This paper constructs a radioisotope distribution model of deep groundwater and obtains the dynamic data of radium and radon on

CO2 geological storage is a key technology for reducing greenhouse gas emissions. But merely injecting CO2 into sedimentary strata has high costs and no direct economic benefit. A more cost-effective and environment-friendly way is storing and utilizing CO2 in deep sedimentary reservoirs for heat extraction. However, the effects of ubiquitous impurities on the sequestration safety and heat extraction

Accurate annual runoff forecasting is of great significance for water resources management and timely flood control. However, nonlinear and non-stationary runoff series and the complexity of hydrological processes make it difficult. To improve forecasting accuracy, a hybrid model based on two-stage decomposition, the support vector machine (SVM), and the combined method is proposed. Firstly, the original

Climate change and riparian management are major drivers of hydrological change, with important implications for nutrient fluxes in lowland streams. However, the coupling of hydrological and nutrient dynamics is complex due to time-variant flow paths, interacting biogeochemical processes and variation in land use, fertilization levels and management measures. Here, we assessed the long-term (30 year)

As the second largest lake in Africa, the extent of Lake Chad has over 50% seasonal variations with large parts of water under aquatic vegetation. Although a great area shrinkage since the 1960s divided the lake into two parts, namely, the northern and southern basins, it still feeds millions of people from four countries around it. Given sparse in situ measurements, remote sensing with seamless spatial

Despite dissolved carbon (C) exports from continents being crucial in the connection between terrestrial, atmospheric and oceanic C pools, the relative contribution and process controls on dissolved organic (DOC) and inorganic (DIC) fluxes within river basins are not fully understood. This paper presents an analysis of data from 843 sites worldwide from 45 Web of Science SCI-Expanded (ex ISI) indexed

The time scales of a catchment hydrologic response in a human impacted intra-Apennine basin, was assessed by a power spectral analysis. Turbidity and streamflow data, at high resolution (10 minutes) have been considered during four years. The turbidity and streamflow have heavy tails that follow approximately Pareto distributions. Both also display scaling Fourier power spectra of the form f-b, over

Estimating extreme precipitation return levels at ungauged locations is key for hydrological applications and risk management, and demands improved techniques to decrease the large uncertainty of traditional methods. Here, we leverage the perks of the simplified Metastatistical extreme value (SMEV) approach with a twofold aim: we show how it can be effectively used in situations in which the ordinary

Accurate detection and monitoring of drought events are important particularly in arid and semi-arid regions of the world. Gravity Recovery and Climate Experiment (GRACE) gravity estimates have been used widely for this purpose and a number of indices have been developed using the GRACE Terrestrial Water Storage Anomalies (TWSA) values. In the current study, a new approach is proposed to enhance the

Excess export of nitrate to streams has been an environmental issue attracting attention across the world. Lumped models based on StorAge Selection (SAS) functions have been used widely to investigate this export processes in terms of hydrological and chemical responses in catchment outflux – both in discharge (Q) and in evapotranspiration (ET). The validity of these models depends on the appropriate

Climate change has already made significant alterations to various elements of the hydrologic cycle. One relatively less attended hydrologic impact of climate change is on the landscape Freeze-Thaw (FT), which largely affects surface and sub-surface hydrology, phenology, and land-atmospheric interactions, particularly in cold regions. Understanding the impacts of climate change on FT patterns, however

Satellite rainfall products are one of the most valuable tools for water resources monitoring in data-scarce regions, due to their low latency and quasi-global range. However, there are still uncertainties associated with rainfall products performance used to estimate hydrologic signatures in several regions, such as Brazil. Here, we investigate the performance of three rainfall products in estimating

Groundwater contaminant source identification (GCSI) can provide support for the confirmation of responsibility and the remediation of pollution. This study has developed an innovative combination algorithm to recognize source properties and model parameters in groundwater contamination simultaneously. The research idea is based on Bayes theory and combines an ensemble smoother (ES) algorithm, differential

Excess nutrients in aquatic ecosystems is a major water quality problem globally. Worsening eutrophication issues are notable in cold temperate areas, with pervasive problems in many agriculturally dominated catchments. Predicting nutrient export to rivers and lakes is particularly difficult in cold agricultural environments because of challenges in modelling snow, soil, frozen ground, climate, and

Drought may affect more people than any other climate extremes worldwide, especially in (semi)arid climates such as Iran. In this paper, the empirical Multivariate Standardized Drought Index (MSDI) that incorporates the meteorological and agricultural drought conditions is first computed. The wavelet analysis is then used to identify teleconnections between ocean–atmosphere oscillations from Atlantic

Groundwater is a life-sustaining resource that supplies water to 2 billion people worldwide and is critical for agriculture. Despite the importance of groundwater, understanding of groundwater recovery from meteorological droughts is limited. Here, we utilize daily groundwater observations from unconfined aquifers without active groundwater management across the conterminous United States to illustrate

Drought is a multifaceted natural phenomenon with diverse spatial and temporal characteristics and significant environmental, social, and economic effects. The utility of conventional drought indices based on the assumption of stationarity is questionable due to the advent of rapid environmental change. We proposed a non-stationary standardized precipitation index (SPINS) to reassess the nature of

Meteorological droughts propagate through the hydrological cycle causing hydrological droughts and societal impacts. However, the effects of climate and basin characteristics on hydrologic drought propagation vary regionally and remain largely unclear. In this paper, we characterize meteorological and hydrological droughts in 457 basins in Brazil. Using the Standardized Precipitation Evapotranspiration

Detecting the hydrological responses of overburden aquifers to mining disturbance is significant in groundwater resource protection and mining safety. Thus, an effective and economical method of tracking such responses is necessary. This paper uses time-series analysis and groundwater tidal-response analysis to identify and quantify the hydrological responses associated with longwall mining, including

The accurate characterization of the underground depositional structure and hydraulic property distribution is essential to understand flow and solute transport in heterogeneous rocks or soils. Hydraulic tomography was shown to be an efficient technique to infer the spatial distribution of hydraulic properties. Due to the fact that information about the sedimentary structures’ distribution is not always

Weirs are commonly used for controlling, measuring, and regulating water flow in conveyance structures such as canals or dams. In this study, hydraulic properties of flow over broad-crested weirs including the effects of different sloping crests and upstream and downstream ramps were characterized by using the finite volume method. Numerical simulations were validated by experimental results; the numerical

Water-repellent soils usually experience water flow impedance during the early stage of a wetting process followed by progressive increase of infiltration rate. Current infiltration models are not formulated to describe this peculiar process. Similarly, simplified methods of soil hydraulic characterization (e.g., BEST) are not equipped to handle water-repellent soils. Here, we present an adaptation

This study presents the first evaluation of using commercial microwave link (CML) data for rainfall measurements in Australia, with the test site being the greater Melbourne Metropolitan area. More than 100 CMLs with microwave frequency ranging between 10 and 40 GHz have been used for the rainfall retrieval. The 15-minute received signal levels (RSLs) for each CML based on two sampling strategies (average

Vegetation plays an active role in soil water dynamics and water balance in groundwater-soil-plant-atmosphere continuum systems. Therefore, we characterized soil water transport at depths of 0–4.0 m induced by root water uptake (RWU) at a groundwater-dependent Salix site during the whole growth stage and compared the results with those from a non-vegetated soil site, in the semiarid Ordos basin of

As an additional source of water to plants besides rainfall, dew may have a positive impact on vegetation in the arid ecosystems. Knowledge regarding dew formation characteristics and its ecological effects on vegetation water status and photosynthetic performance in the gravel desert ecosystem is still lacking. In this study, the dew variability and formation frequency on a gravel desert were measured

Groundwater flooding (or infiltration) in sewer systems leads to significant negative consequences such as discharge of untreated sewage, reduction of system capacity, structural deterioration, and dilution of the wastewater stream delivered to a treatment plant causing malfunction. Cities with aging networks along coastal areas, where aquifers are shallow, are particularly vulnerable. Rehabilitation

Glacier mass balance provides a sensitive barometer of climate-glacier interactions, yet only a few glaciers have been continuously well-documented. Here we evaluated the retreat status of Baishui River Glacier No. 1 (reference glacier of Yulong Snow Mountain) during the 1951-2020 period and explored its response to climate change. In particular, based on 12-years of continuous in-situ measurements

This discussion is reply to the comments made by Dr. Hyun Il Choi (in press) on the LME proposed by Liu, 2020 concerning the performance criterion for hydrological model. In this reply I answer the comments and I try to clarify that there are two aspects of the LME. I believe that Dr. HyunIl Choi had just understood one aspects of the LME in his comments, which had confused him. Actually, both the

Natural conditions of surface water bodies and groundwater aquifers in the North China Plain (NCP) have been altered to meet the ever-growing human water demands. Several water resources management measures have been implemented in recent decades to alleviate groundwater depletion, maintain ecological resilience, and sustain agricultural production. This study aims to investigate their impacts on land

Groundwater (GW) is a vital resource for human consumption, agriculture, environmental sustainability, and socio-economic development in different parts of the world. Besides, GW plays a crucial role in minimizing the impacts during extreme drought events. However, there is a fast decline in groundwater resources due to increased sectoral water demand compounded by reduced rainfall and rising temperature

Climate change is driving an increase in the frequency and intensity of extreme weather events, with alterations to the functioning of the water cycle. Global-scale assessments of shifts in the hydrologic response to climatic perturbations (i.e. hydrologic sensitivity) are needed to identify regions where mitigation efforts will be necessary to avert detrimental changes on terrestrial water resources

Evapotranspiration (ET) plays a vital role in the water cycle and energy cycle and serves as an important linkage between ecological and hydrological processes. Accurate estimation of ET based on data-driven methods is of great theoretical and practical significance for exploring soil evaporation, plant transpiration and the regional hydrological balance. Most existing estimation approaches were proposed

Calibration is necessary for improving raw forecasts generated by global climate models (GCMs) to fully utilize potential benefits of the forecasts in practical applications. Based on quantile mapping (QM), this paper proposes a five-parameter Gamma-Gaussian model to calibrate monthly and seasonal GCM precipitation forecasts. While QM directly maps forecasts to observations without accounting for the

Three years of observations of groundwater elevations, ocean tides, surge, and waves, and rainfall are used to study coastal groundwater-driven flooding along the ocean side of a barrier island. Increases in surge and wave-driven water levels (setup) during 26 ocean storms with little rainfall, including the passage of 3 hurricanes, caused O(1 m) increases in groundwater heads under the dunes on the

The fragile ecosystem of the desiccated Amu Darya River Basin (ADRB) has experienced profound local hydrological havoc. These changes are associated with temperature, evapotranspiration, precipitation, and human-induced effects. However, previous long-term analyses have inadequately addressed these problems at the basin scale. Therefore, this study applied the elasticity coefficient method coupled

It is crucial to investigate how a precipitation deficit is transformed into hydrological drought and how climate change and human activities affect this transformation process, which is helpful to gain a deep understanding of drought propagation process in this changing environment. This study proposed an observation-based natural and human-impacted catchment comparison method to assess the impacts

A multiscalar standardized terrestrial water storage index (STI) is proposed to assess global hydrological droughts in this study. STI is defined as the standardized statistical deviation of terrestrial water storage (TWS) measured by GRACE to the climatology at multiple time scales. Because of the statistical nature of its definition, the proposed index is comparable to other standardized drought

With a copula-based probabilistic model, this study presents a global view on the propagation of meteorological to soil moisture drought. Meta-Gaussian and three-dimensional vine copulas were employed to construct the bivariate and trivariate conditional joint drought distributions, respectively, using the time series of standardized precipitation evapotranspiration index (SPEI) and standardized soil

The longitudinal profile of rivers in active orogenic belts records the competitive process occurring between erosion and uplift, and the knickpoint, as a unique sign, can support this. A series of distinctive knickpoints are distributed at different heights in the basin of the Layue River, which is a tributary located on the northwest side of the Yurlung Tsangpo Basin, China. By combining the stream

Understanding the annual variation in the transpiration to evapotranspiration ratio (T/ET) remains a challenge and is essential for a thorough understanding of plant responses to the changing environment. We obtained the annual dynamics of T/ET in a semi-arid area of the southwestern United States based on the medians of monthly T/ET derived from two ET partitioning methods. The variation in monthly

Millions of cubic meters of water are lost every year from water utilities, with detrimental consequences on the environment and on society. However, this large amount of water is not necessarily lost. Although leaking water utilities have the potential to recharge urban aquifers, very little is known about the fate of leaked water and its interaction with subsurface anthropogenic features, such as

Tropical peat swamp forests (PSFs) play a significant role in the exchange of water between land and the atmosphere. However, fire and drainage have been expanding in PSFs in recent decades. Although there is concern on the influence of fire and drainage on water circulation, their influence on evapotranspiration (ET) is insufficiently understood. Furthermore, repeated fire occurrences and their corresponding

The frequency of extreme precipitation is increasing globally and poses a significant threat to human and natural systems. At the regional scale, these changes are becoming increasingly uncertain. Therefore, it is critical to understand the spatiotemporal evolution of extreme precipitation on a regional scale. In this study, we applied the connected component labelling algorithm to define regional

Errors in hydrological simulations have impacted their applications in flood prediction and water resources management. Properly characterizing the properties of errors such as heteroscedasticity and autocorrelation can provide improved hydrological predictions. Here, we present a probabilistic Long Short-Term Memory (LSTM) network for modeling hydrological residual errors. Three steps are undertaken

Dissolved organic matter (DOM) entering the river networks affects aquatic ecosystems, yet it remains difficult to quantify the strength of various environmental factors in controlling reach-scale uptake and transport of DOM. This study combined reach-scale field experiments and stochastic modeling to investigate the uptake and transport dynamics of natural fluorescent DOM (FDOM) in a forested coastal

Groundwater interacts with porewater within clay-rich sequences. However, the effects of aquitard porewater on groundwater quality are generally poorly understood. This study explores potential links between porewater chemistry in a thick clay-rich sequence of Quaternary sediments, and groundwater quality in the North China Plain (NCP), one of China’s most important water supply aquifers. Previous

To explore the permeability and collapsibility characteristics of sandy loess in northern Loess Plateau of China, the in-situ tests were carried out by monitoring information of moisture content and collapse deformation in the soil layers. The laws in conditions of simulated rainfall infiltration and saturated infiltration were compared and analyzed. The main results are as follows. (1) The water infiltrates

Urban green infrastructure (GI) such as biofiltration systems (also known as bioretention, biofilters, rain gardens) are being increasingly implemented in different parts of the world to enhance urban greening whilst controlling stormwater pollution. Treatment effectiveness has been shown to be reliant upon the surrounding climate, including rainfall patterns (e.g. length of wet and dry weather) and

Accurate estimation of groundwater recharge in regions with limited water and thick unsaturated zones is challenging because of the limited water flux. This study aims to employ multiple tracers and methods to investigate the mechanism of groundwater recharge in the thick loess deposits of China. We collected soil samples under different vegetation, unconfined groundwater, and precipitation to determine