Soils lie at the interface between the atmosphere and the subsurface and are a key component that control ecosystem services, food production, and many other processes at the Earth's surface. There ...is a long-established convention for identifying and mapping soils by texture. These readily available, georeferenced soil maps and databases are used widely in environmental sciences. Here, we show that these traditional soil classifications can be inappropriate, contributing to bias and uncertainty in applications from slope stability to water resource management. We suggest a new approach to soil classification, with a detailed example from the science of hydrology. Hydrologic simulations based on common meteorological conditions were performed using HYDRUS-1D, spanning textures identified by the United States Department of Agriculture soil texture triangle. We consider these common conditions to be: drainage from saturation, infiltration onto a drained soil, and combined infiltration and drainage events. Using a k-means clustering algorithm, we created soil classifications based on the modeled hydrologic responses of these soils. The hydrologic-process-based classifications were compared to those based on soil texture and a single hydraulic property, Ks. Differences in classifications based on hydrologic response versus soil texture demonstrate that traditional soil texture classification is a poor predictor of hydrologic response. We then developed a QGIS plugin to construct soil maps combining a classification with georeferenced soil data from the Natural Resource Conservation Service. The spatial patterns of hydrologic response were more immediately informative, much simpler, and less ambiguous, for use in applications ranging from trafficability to irrigation management to flood control. The ease with which hydrologic-process-based classifications can be made, along with the improved quantitative predictions of soil responses and visualization of landscape function, suggest that hydrologic-process-based classifications should be incorporated into environmental process models and can be used to define application-specific maps of hydrologic function.
Fast neutrons are generated naturally at the land surface by energetic cosmic rays. These “background” neutrons respond strongly to the presence of water at or near the land surface and represent a ...hitherto elusive intermediate spatial scale of observation that is ideal for land surface studies and modeling. Soil moisture, snow, and biomass each have a distinct influence on the spectrum, height profile, and directional intensity of neutron fluxes above the ground, suggesting that different sources of water at the land surface can be distinguished with neutron data alone. Measurements can be taken at fixed sites for long‐term monitoring or in a moving vehicle for mapping over large areas. We anticipate applications in many previously problematic contexts, including saline environments, wetlands and peat bogs, rocky soils, the active layer of permafrost, and water and snow intercepted by vegetation, as well as calibration and validation of data from spaceborne sensors.
Soil moisture content on a horizontal scale of hectometers and at depths of decimeters can be inferred from measurements of low-energy cosmic-ray neutrons that are generated within soil, moderated ...mainly by hydrogen atoms, and diffused back to the atmosphere. These neutrons are sensitive to water content changes, but largely insensitive to variations in soil chemistry, and their intensity above the surface is inversely correlated with hydrogen content of the soil. The measurement with a portable neutron detector placed a few meters above the ground takes minutes to hours, permitting high-resolution, long-term monitoring of undisturbed soil moisture conditions. The large footprint makes the method suitable for weather and short-term climate forecast initialization and for calibration of satellite sensors, and the measurement depth makes the probe ideal for studies of plant/soil interaction and atmosphere/soil exchange.
We hydrologists can do a better job of supporting water‐resources decision‐making. I will argue that we can do this by recognizing that decision makers use qualitative, multiple‐narrative approaches. ...So, rather than providing single‐model predictions with quantitative uncertainties, we should develop teams of rival models that inform decision makers about what is known, what is possible, and what is unknown. This requires that we build ensembles of models that include biased, advocacy models that directly represent stakeholders' interests or concerns. From this inclusive platform, we can speak objectively and clearly about the risks that drive stakeholders' decisions. Furthermore, we will be promoting more appropriate use of the scientific method in making informed water‐resources decisions.
Article Impact Statement: Teams of rival models, including biased, advocacy models, may better inform decision‐makers than a single model accompanied with quantified uncertainty.
Purpose
Ferromagnetic foreign bodies (FFB) present during magnetic resonance imaging (MRI) explorations can lead to tissue injury due to movement, especially in and around the eyes. Ferromagnetic ...foreign bodies located in the intraocular area, eyelids, and orbit are thus prohibited from undergoing MRI. The aim of the study was to analyze movement of 4-mm ferromagnetic foreign bodies in MRI in the eye, eyelid, and orbit using computed tomography (CT) scan.
Method
We developed a porcine model using 12 quarters of fresh porcine heads. Each porcine head included one whole orbit with the ocular globe, orbital fat, muscles, and eyelids. Four-millimeter FFB were implanted in the eye within 2 days post-slaughter, and images were acquired within 5 days post-slaughter. Four-millimeter FFB movement was analyzed after 1.5-Tesla (T) MRI. Four locations were tested: intravitreous, suprachoroidal, intraorbital fat, and intrapalpebral. Movement analysis was assessed using computed tomography (CT) scan.
Results
The intravitreous ferromagnetic ball moved 14.0 ± 8.8 mm (
p
< 0.01), the suprachoroidal ball moved 16.8 ± 5.4 mm (
p
< 0.01), the intraorbital fat ball moved 5.8 ± 0.9 mm (
p
> 0.05), and the intrapalpebral ball moved 2.0 ± 0.4 mm (
p
> 0.05).
Conclusion
The ex vivo porcine model was able to study FFB movement. The 4-mm ferromagnetic balls moved in intravitreous and in suprachoroidal locations after MRI.
Access to accurate spatio-temporal groundwater level data is crucial for sustainable water management in Chile. Despite this importance, a lack of unified, quality-controlled datasets have hindered ...large-scale groundwater studies. Our objective was to establish a comprehensive, reliable nationwide groundwater dataset. We curated over 120,000 records from 640 wells, spanning 1970-2021, provided by the General Water Resources Directorate. One notable enhancement to our dataset is the incorporation of elevation data. This addition allows for a more comprehensive estimation of groundwater elevation. Rigorous data quality analysis was executed through a classification scheme applied to raw groundwater level records. This resource is invaluable for researchers, decision-makers, and stakeholders, offering insights into groundwater trends to support informed, sustainable water management. Our study bridges a crucial gap by providing a dependable dataset for expansive studies, aiding water management strategies in Chile.
Time‐lapse gravity data provide a direct, nondestructive method to monitor mass changes at scales from centimeter to kilometer. But, the effectively infinite spatial sensitivity of gravity ...measurements can make it difficult to isolate the signal of interest. The variable baseline gravity gradient method, based on the difference of measurements between two gravimeters, is an alternative to the conventional approach of individually modeling all sources of mass and elevation changes. This approach can improve the signal‐to‐noise ratio for many applications by removing the contributions of Earth tides, loading, and other signals that have the same effect on both gravimeters. At the same time, this approach can focus the support volume within a relatively small user‐defined region of the subsurface. The method is demonstrated using paired superconducting gravimeters to make for the first time a large‐scale, noninvasive measurement of infiltration wetting front velocity and change in water content above the wetting front.
Key Points
Variable baseline gravity gradients are measured between two or more gravimetersGradient measurements eliminate ocean and atmospheric loading noiseInfiltration rate and change in water content is estimated using gradient data
Accurate estimation of groundwater recharge (GR) and evapotranspiration (ET) are essential for sustainable management of groundwater resources, especially in arid and semi‐arid regions. In the Manas ...River Basin (MRB), water shortage is the main factor restricting sustainable development of irrigated agriculture, which relies heavily on groundwater. Film‐mulched drip irrigation significantly changes the pattern and dominant processes of water flow in the unsaturated zone, which increases the difficulty of GR and ET estimation. To better estimate GR and ET under film‐mulched drip irrigation in the MRB, bromide tracer tests and soil lithologic investigation were conducted at 12 representative sites. A one‐dimensional variably saturated flow model (HYDRUS‐1D) was calibrated at each site using soil evaporation data inferred from the bromide tracer tests. The results showed that average annual soil evaporation in uncultivated lands calculated from bromide trace tests was 25.55 mm. The annual GR ranged from 5.5 to 37.0 mm under film‐mulched drip irrigation. The annual ET ranged from 507.0 to 747.1 mm, with soil evaporation between 35.7 and 117.0 mm and transpiration between 460.9 and 642.3 mm. Soil evaporation represented 7% to 16% of the total ET and more than 70% of precipitation and irrigation water was used by cotton plants. Spatial variations of soil lithology, water table depth and initial soil water content led to the spatial differences of GR and ET in the MRB. Our study indicated that bromide tracer tests are useful for inferring ET in the arid and semi‐arid oases. The combination of bromide tracer tests and HYDRUS‐1D enhances reliability for estimation of GR and ET under film‐mulched drip irrigation in the MRB and shows promise for other similar arid inland basins around the world.
This paper proposes a framework to quantify groundwater recharge (GR) and evapotranspiration (ET) under film‐mulched drip irrigation in the Manas River Basin (MRB). Artificial bromide tracer tests are useful for inferring ET in the arid and semi‐arid oases. The combination of bromide tracer tests and HYDRUS‐1D enhances reliability for estimation of GR and ET under film‐mulched drip irrigation in the MRB and shows promise for other similar arid inland basins around the world.
High‐elevation mountain catchments are often subject to large climatic and topographic gradients. Therefore, high‐density hydrogeochemical observations are needed to understand water sources to ...streamflow and the temporal and spatial behaviour of flow paths. These sources and flow paths vary seasonally, which dictates short‐term storage and the flux of water in the critical zone (CZ) and affect long‐term CZ evolution. This study utilizes multiyear observations of chemical compositions and water residence times from the Santa Catalina Mountains Critical Zone Observatory, Tucson, Arizona to develop and evaluate competing conceptual models of seasonal streamflow generation. These models were tested using endmember mixing analysis, baseflow recession analysis, and tritium model “ages” of various catchment water sources. A conceptual model involving four endmembers (precipitation, soil water, shallow, and deep groundwater) provided the best match to observations. On average, precipitation contributes 39–69% (55 ± 16%), soil water contributes 25–56% (41 ± 16%), shallow groundwater contributes 1–5% (3 ± 2%), and deep groundwater contributes ~0–3% (1 ± 1%) towards annual streamflow. The mixing space comprised two principal planes formed by (a) precipitation‐soil water‐deep groundwater (dry and summer monsoon season samples) and (b) precipitation‐soil water‐shallow groundwater (winter season samples). Groundwater contribution was most important during the wet winter season. During periods of high dynamic groundwater storage and increased hydrologic connectivity (i.e., spring snowmelt), stream water was more geochemically heterogeneous, that is, geochemical heterogeneity of stream water is storage‐dependent. Endmember mixing analysis and 3H model age results indicate that only 1.4 ± 0.3% of the long‐term annual precipitation becomes deep CZ groundwater flux that influences long‐term deep CZ development through both intercatchment and intracatchment deep groundwater flows.
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