Preprints
Filtering by Subject: Hydrology
Drivers of phytoplankton responses to summer storms in a stratified lake: a modelling study
Published: 2021-08-03
Subjects: Hydrology, Other Environmental Sciences, Terrestrial and Aquatic Ecology
Extreme wind events affect lake phytoplankton amongst others by deepening the mixed layer and increasing internal nutrient loading. Both increases and decreases of phytoplankton biomass after storms have been observed, but the precise mechanisms driving these responses remain poorly understood or quantified. In this study, we coupled a one-dimensional physical model to a biogeochemical model to [...]
The world’s second-largest, recorded landslide event: lessons learnt from the landslides triggered during and after the 2018 Mw 7.5 Papua New Guinea earthquake
Published: 2021-07-30
Subjects: Geology, Geomorphology, Geophysics and Seismology, Hydrology, Other Earth Sciences
Widespread landslide events provide rare but valuable opportunities to investigate the spatial and size distributions of landslides in relation to seismic, climatic, geological and morphological factors. This study presents a unique event inventory for the co-seismic landslides induced by the February 25, 2018 Mw 7.5 Papua New Guinea earthquake as well as its post-seismic counterparts including [...]
Toward automating post processing of aquatic sensor data
Published: 2021-07-23
Subjects: Biogeochemistry, Civil Engineering, Environmental Engineering, Environmental Monitoring, Hydrology
Sensors measuring environmental phenomena at high frequency commonly report anomalies related to fouling, sensor drift and calibration, and datalogging and transmission issues. Suitability of data for analyses and decision making often depends on manual review and adjustment of data. Machine learning techniques have potential to automate identification and correction of anomalies, streamlining [...]
Onset of runaway fragmentation of salt marshes
Published: 2021-07-01
Subjects: Earth Sciences, Geomorphology, Hydrology, Sustainability
Salt marshes are valuable but vulnerable coastal ecosystems that adapt to relative sea level rise (RSLR) by accumulating organic matter and inorganic sediment. The natural limit of these processes defines a threshold rate of RSLR beyond which marshes drown, resulting in ponding and conversion to open waters. We develop a simplified formulation for sediment transport across marshes to show that [...]
Multidimensional simulation of PFAS transport and leaching in the vadose zone: impact of surfactant-induced flow and soil heterogeneities
Published: 2021-07-01
Subjects: Environmental Health and Protection, Hydrology, Soil Science
PFAS are emergent contaminants of which fate and transport in the environment remain poorly understood. As surfactants, adsorption at air-water interfaces and solid surfaces in soils complicates the retention and leaching of PFAS in the vadose zone. Recent modeling studies accounting for the PFAS-specific nonlinear adsorption processes predicted that the majority of long-chain PFAS remain in the [...]
Phosphorus Retention in Lakes: A Critical Reassessment of Hypotheses and Static Models
Published: 2021-06-24
Subjects: Engineering, Environmental Engineering, Hydraulic Engineering, Hydrology, Water Resource Management
Various hypotheses and models for phosphorus (P) retention in lakes are reviewed and 39 predictive models are assessed in three categories, namely mechanistic, semi-mechanistic, and strictly-empirical models. A large database consisting of 738 data points is gathered for the analyses. Assessing four pairs of competing hypotheses used in mechanistic models, we found that (i) simulating lakes as [...]
Fluid invasion dynamics in porous media with complex wettability and connectivity
Published: 2021-06-18
Subjects: Chemical Engineering, Complex Fluids, Earth Sciences, Fluid Dynamics, Hydrology, Materials Science and Engineering, Other Materials Science and Engineering, Petroleum Engineering, Transport Phenomena
Multiphase flow is important for many natural and engineered processes in subsurface geoscience. Pore-scale multiphase flow dynamics are commonly characterized by an average balance of driving forces. However, significant local variability in this balance may exist inside natural, heterogeneous porous materials, such as rocks and soils. Here, we investigate multiphase flow in heterogeneous rocks [...]
Turbulent flow effects in hydraulic fracture propagation in permeable rock
Published: 2021-06-14
Subjects: Fluid Dynamics, Hydraulic Engineering, Hydrology, Numerical Analysis and Scientific Computing, Oil, Gas, and Energy
This chapter considers a model for a radial hydraulic fracture propagation in a permeable, linear elastic rock formation driven by a point source fluid injection. The linear elastic fracture mechanics theory controls the quasi-static propagation. The hydraulic fracturing fluid is slickwater -- pure water solution with polymeric additives which allow reducing the fluid flow friction in the [...]
Multi-task deep learning of daily streamflow and water temperature
Published: 2021-06-04
Subjects: Hydrology, Physical Sciences and Mathematics
Deep learning models can accurately predict many hydrologic variables including streamflow and water temperature; however, these models have typically predicted hydrologic variables independently. This study explored the benefits of modeling two interdependent variables, daily average streamflow and daily average stream water temperature, together using multi-task deep learning. A multi-task [...]
A field guide for monitoring riverine macroplastic entrapment in water hyacinths
Published: 2021-06-01
Subjects: Environmental Monitoring, Fresh Water Studies, Hydrology, Remote Sensing
River plastic pollution is an environmental challenge of growing concern. However, there are still many unknowns related to the principal drivers of river plastic transport. Floating aquatic vegetation, such as water hyacinths, have been found to aggregate and carry large amounts of plastic debris in tropical river systems. Monitoring the entrapment of plastics in hyacinths is therefore crucial [...]
Advancing flood warning procedures in ungauged basins with machine learning.
Published: 2021-05-27
Subjects: Artificial Intelligence and Robotics, Hydrology
Flood prediction across scales and more specifically in ungauged areas remains still a great challenge that limits the efficiency of flood risk mitigation strategies and disaster preparedness. Building upon the recent success of Machine Learning (ML) models on streamflow prediction, this work presents a prototype ML-based framework for flood warning and flood peak prediction. The fundamental [...]
Quantifying the impact of lagged hydrological responses on the effectiveness of groundwater conservation
Published: 2021-05-27
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
Many irrigated agricultural areas seek to prolong the lifetime of their groundwater resources by reducing pumping. However, it is unclear how lagged responses, such as reduced groundwater recharge caused by more efficient irrigation, may impact the long-term effectiveness of conservation initiatives. Here, we use a variably saturated, simplified surrogate groundwater model to: 1) analyze aquifer [...]
The importance of threshold in alluvial river channel geometry and dynamics
Published: 2021-05-27
Subjects: Fluid Dynamics, Geomorphology, Hydrology, Sedimentology, Statistical, Nonlinear, and Soft Matter Physics, Water Resource Management
Many cities and settlements are organized around alluvial rivers, which are self-formed channels composed of gravel, sand and mud. Much of the time alluvial river channels are oversized, in that they could accommodate greater water flow; yet during extreme storms they are woefully undersized, and potentially catastrophic flooding can occur. Considering widely varying hydroclimates, sediment [...]
A radial hydraulic fracture driven by a Herschel–Bulkley fluid
Published: 2021-05-27
Subjects: Fluid Dynamics, Hydraulic Engineering, Hydrology, Numerical Analysis and Scientific Computing, Oil, Gas, and Energy, Volcanology
We analyse the influence of fluid yield stress on propagation of a radial (penny-shaped) hydraulic fracture in a permeable reservoir. In particular, the Herschel-Bulkley rheological model is adopted that includes yield stress and non-linearity of the shear stress. The rock is assumed to be linear elastic, and the fracture is driven by the point source fluid injection with a constant volumetric [...]
Geochemical signatures of rare earth elements and yttrium in the vicinity of an ion-adsorption type deposit: roles of source sediment control
Published: 2021-05-13
Subjects: Biogeochemistry, Geochemistry, Geology, Hydrology
The elevated concentrations of rare earth elements (REE) and yttrium (REE+Y) in acid mine drainage (AMD) constitute an opportunity for REE+Y recovery. However, the source and control of REE+Y signatures in AMD remains uncertain. Water, rock, sediment and sludge samples were collected from an ion-adsorption rare earth mining area to investigate REE+Y concentration and fractionation patterns in [...]