Preprints
Filtering by Subject: Hydrology
Flooded Rivers, Drying Wetlands, Vanishing Tributaries: Hydrological Paradox of the East Ganga Plains
Published: 2026-08-16
Subjects: Environmental Monitoring, Geomorphology, Hydrology, Natural Resources Management and Policy, Physical Sciences and Mathematics, Sustainability, Water Resource Management
The East Ganga Plains (EGP) present a striking hydrological paradox: while embanked rivers flood with increasing magnitude, adjacent wetlands and groundwater-fed streams are desiccating, and aquifer storage is declining. Using satellite remote sensing and gravimetry, we document that: (i) wetlands exhibit significant water-cover loss despite stable monsoon rainfall; (ii) small rivers and [...]
PyRiverShift: A Gaussian Transect Decomposition Framework for Quantifying Sub-Pixel Lateral Channel Mobility
Published: 2026-08-16
Subjects: Applied Statistics, Earth Sciences, Environmental Indicators and Impact Assessment, Environmental Monitoring, Geomorphology, Hydrology, Physical Sciences and Mathematics, Sedimentology, Water Resource Management
Along many rivers, lateral channel mobility is a key process, yet quantification from freely available multi-decadal 30 m Landsat imagery is constrained by low pixel resolution relative to channel width. We introduce PyRiverShift, a sensor-agnostic spectral decomposition framework. PyRiverShift fits a 1-D Gaussian to NDWI profiles along valley-perpendicular transects, recovering sub-pixel channel [...]
Locating the Anthropogenic Drivers of Urban Flooding from Centimetre-Resolution Aerial Imagery: A Reproducible Open-Data Pipeline for the Odaw Basin, Accra
Published: 2026-08-12
Subjects: Earth Sciences, Environmental Sciences, Hydrology, Physical Sciences and Mathematics
Recurrent inundation in metropolitan Accra is, on the preponderance of the evidence, an anthropogenic rather than a climatological phenomenon: its proximate determinants are the obstruction of drainage by solid waste and the encroachment of structures onto watercourses. These determinants are metre-scale and therefore invisible to the moderate-resolution satellite imagery on which prior work has [...]
Hydroclimatic Regime Shifts and Compound Heat–Dry Events in Rajshahi Division, Bangladesh: Integrating Thermal Gradients, Change-Point Detection, and Heat-Driven Dryness Dynamics (1992–2022)
Published: 2026-08-07
Subjects: Climate, Environmental Indicators and Impact Assessment, Environmental Monitoring, Hydrology, Meteorology, Other Earth Sciences, Other Oceanography and Atmospheric Sciences and Meteorology, Statistical Models
Hydroclimatic variability and compound climate extremes are increasingly affecting monsoon-dominated regions of South Asia, particularly drought-prone northwestern Bangladesh. However, integrated assessments of thermal dynamics, atmospheric moisture, land–atmosphere coupling, and compound heat–dry events remain limited in the regional context. Therefore, this study investigated long-term [...]
River dissolved inorganic carbon losses from the Andes to lowland Amazon via cryptic sedimentary exchange processes
Published: 2026-08-05
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geomorphology, Hydrology
River carbon transfers and associated greenhouse gas emissions are a major component of the carbon cycle. Proposals to use rivers and their catchments to increase carbon dioxide (CO2) drawdown, by enhanced rock weathering and river alkalinity enhancement, require secure delivery of dissolved inorganic carbon (DIC) and increased cation loads (e.g. Ca2+) to the ocean. Here we explore the fate of [...]
Global Flood Mapper v2: Open-Access Flood Mapping and Exposure Assessment with Sentinel-1 SAR
Published: 2026-07-31
Subjects: Environmental Monitoring, Hydrology
We present Global Flood Mapper v2 (GFM v2), which adds flood depth estimation, on-demand GeoTIFF export, cloud-based impact assessment against high-resolution land cover and five global population datasets to quantify exposure uncertainty, and parameter-encoded URLs for reproducibility and sharing. Its predecessor, GFM v1, was already an open-access, globally operational web portal for rapid, [...]
Stress-Conditioned Lightweight Flash-Drought Detection in the US Corn Belt Using MODIS NDVI and ERA5-Land
Published: 2026-07-29
Subjects: Hydrology, Meteorology
Flash-drought monitoring by classical indices averages predictive signal across calm and stressed years, blunting the signal exactly where it matters. We show empirically that the coupling between precipitation, soil moisture, vapor pressure deficit (VPD), and NDVI is stress-conditional: the hydrological pathway is visible when vegetation is already under stress (Spearman rho of about 0.18 for [...]
Detecting illegal water abstractions using Earth Observation and artificial intelligence: challenges, research gaps, and future directions
Published: 2026-07-28
Subjects: Artificial Intelligence and Robotics, Environmental Monitoring, Hydrology, Natural Resources Management and Policy, Remote Sensing, Water Resource Management
Water scarcity and unsustainable withdrawals are major environmental challenges, particularly in semi-arid and Mediterranean regions where agriculture places strong pressure on limited hydrological resources. Illegal or unreported water abstractions intensify these pressures by undermining ecosystem stability, policy compliance, and long-term water security. Although Earth Observation (EO) and [...]
Connectivity effects on fluid age and residence time distributions in two- and three-dimensional pore networks
Published: 2026-07-27
Subjects: Biogeochemistry, Earth Sciences, Hydrology, Physical Sciences and Mathematics
Pore-scale simulations are often run on a single plane cut from a three-dimensional image, because resolving the whole pore space is expensive. This study asks what that shortcut costs. What is at stake is the distribution of fluid ages, and above all its long tail, because that tail is what slow reactions respond to. We computed the distribution directly from the flow field, by labeling the [...]
Reconstructing age and reactivity distributions from the moments carried by central-moment transport models
Published: 2026-07-26
Subjects: Biogeochemistry, Earth Sciences, Hydrology, Physical Sciences and Mathematics
A central-moment transport model follows a property that varies across a population, such as the age of water parcels or the decay rate of organic-matter particles. Instead of storing the whole distribution of that property, it keeps only a few summary numbers, the moments, and moves those through the model. But the distribution itself is usually what a scientist wants, so it has to be rebuilt [...]
Mechanical Association between Pressure Wave Propagation Time and Constitutive Parameter Damage in Porous Media: Theoretical Derivation and Sensitivity Analysis
Published: 2026-07-16
Subjects: Engineering Mechanics, Geology, Geophysics and Seismology, Geotechnical Engineering, Hydraulic Engineering, Hydrology, Physics, Soil Science
The propagation time of pressure waves in porous media carries critical information about the constitutive parameters of the medium. This study rigorously derives the mechanical relationship between the lag time of pressure wave and the hydraulic parameters of porous media based on the diffusion wave equation. The lag time is shown to be a direct functional of the hydraulic conductivity and [...]
CSUFlow25: Colorado Streamflow Ungaged Prediction Models
Published: 2026-07-07
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics, Water Resource Management
CSUFlow25 is an updated set of statistical models for predicting streamflow in ungaged basins in Colorado, USA. It builds on the earlier CSUFlow18 models (Eurich et al., 2021) by extending the streamflow record from water years 2001–2018 to 2001–2024, expanding the pool of candidate predictor variables, and increasing the number of streamflow metrics predicted. Models were developed from a [...]
SWMMCanada: An Open-Source Service for Generating Ready-to-Run Urban Drainage Models Across Canada
Published: 2026-07-03
Subjects: Civil and Environmental Engineering, Computational Engineering, Engineering, Environmental Engineering, Geotechnical Engineering, Hydrology, Software Engineering
Urban stormwater modelling is often slowed more by data preparation than by the simulation itself, because rainfall, terrain, land cover, soil, and pipe network data usually come from different agencies, formats, projections, and data structures. This software paper presents SWMMCanada, an open source and standardized model building service that makes Canadian urban hydrological modelling easier [...]
Quantifying Watershed Criticality via Deep Learning and Explainable AI for Groundwater Resilience
Published: 2026-07-02
Subjects: Civil and Environmental Engineering, Earth Sciences, Environmental Engineering, Environmental Sciences, Hydrology, Water Resource Management
Groundwater is a vital freshwater resource that supports drinking water supply, agricultural sustainability, ecosystem functioning, and drought resilience. As water scarcity and climate change impacts intensify, sustainable groundwater management plays an important role in groundwater management, with groundwater storage (GWS) acting as a key indicator of groundwater resilience. This study [...]
Merge Satellite and Gauge Daily Precipitation Data for Areas with Sparse-Gauge and Rugged Terrain: A High-Accuracy Gridded Dataset CGS01 (2000-2024) across China
Published: 2026-07-02
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
High-precision quantiffcation of regional precipitation is the foundation of watershed water balance analysis and water resources management. However, current approaches are hindered by methodological diversity and inconsistent results, with limited accuracy, especially in gauge-sparse regions and areas with drastic topographic relief. This study proposes a dual thin-plate spline (TPS) fusion [...]