In this presentation, we will review version 5 of HYDRUS, which resulted from merging earlier versions of HYDRUS-1D (4.x) and HYDRUS (2D/3D) (3.x), implementing the new integrated form of coupling PHREEQC with HYDRUS (HPx), and including new modules such as Furrow, PFAS, Particle Tracking, Dynamic Plant Uptake, Cosmic, Stable Isotopes, C-Ride, etc. The new HYDRUS GUI dramatically improves graphical capabilities and extends its compatibility to new Windows-based (e.g., 64) bit) operating systems. The new modules and capabilities include: a) the Particle Tracking module (to calculate soil water’s transit times and their frequency distributions), b) the Cosmic module (to calculate cosmic-ray neutron fluxes and to use them to inversely estimate large-scale soil hydraulic properties), c) the Dynamic Plant Uptake (DPU) module (to calculate the translocation and transformation of chemicals in the soil-plant continuum), d) the PFAS module (to consider sorption on the air-water interface and the effects of concentration on viscosity and surface tension, and correspondingly on conductivities and pressure heads), e) the Isotope module (to consider the fate and transport of soil water isotopes with evaporation fractionation, f) the C-Ride module (to consider colloid and colloid-facilitated solute transport), and many other new options and graphical (e.g., two-dimensional z-t graphs of main variables) capabilities. Several nonstandard HYDRUS modules (e.g., accounting for overland flow, freezing/thawing, and alternative root water uptake models) will also be discussed.  

How to cite: Simunek, J., Brunetti, G., Jacques, D., Zhou, T., and Šejna, M.: Numerical Modeling of Vadose Zone Processes using Version 5 of HYDRUS and its Specialized Modules, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10247, https://doi.org/10.5194/egusphere-egu23-10247, 2023.

Secondary salinization has long been reported in the Roxo Irrigation District (RID), in southern Portugal, due to use of saline prone irrigation water and the existence of poor structured soils. This study evaluates the soil water and salt budgets in nine commercial orchards located in the RID using the multiple ion chemistry module available in the HYDRUS-1D model during the 2019 and 2020 growing seasons. The study crops were almond, olive, citrus, and pomegranate. The model successfully simulated soil water contents measured in the different fields along two seasons. There was a clear underestimation of the EC_e in some fields while simulations of SAR were found to be acceptable. Modeling errors were mostly associated to missing information on fertigation events rather than difficulties in simulating the effect of irrigation water quality on soil quality. The water and salt balances were also computed for the 1979-2020 period. Considering the probability of distribution of salt accumulation during this period, the risk of salt accumulation was very high, except in the citrus areas. The factors influencing the salinity build-up in the study sites were the irrigation strategy, the seasonal irrigation and rainfall depths, the crop growing period, rainfall distribution in the late and non-growing seasons, soil drainage conditions, and irrigation water quality. On the other hand, for current climate conditions and irrigation water quality, the risk of soil salinity levels affecting crop development and yields were found to be minor. Only in two of the study sites, there was the need to promote salt leaching following strategies that differed between locations. This study further aims to promote sustainable irrigation management practices through the better use of soil and water resources in the Alentejo region of southern Portugal.

How to cite: Ramos, T., Darouich, H., Oliveira, A., Farzamian, M., and Gonçalves, M.: Soil salinization risks under current climate and irrigation management in orchards of southern Portugal, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7560, https://doi.org/10.5194/egusphere-egu23-7560, 2023.

Form and function are two major characteristics describing hydrological systems and can also be helpful in the context of understanding and analyzing unsaturated flow. Whereas the term “form” summarizes the structure and properties of the system, the term “function” represents the hydrological response. Form parameters such as structural and hydraulic soil properties, but also vegetation cover, have a major influence on the subsurface hydrological response. The combination of different soil and surface properties affects the formation of subsurface hydrological flow paths and their interaction and feedbacks can lead to the formation of preferential flow paths that are difficult to characterize and predict. Little is known about how these characteristics co-evolve over time and how form impacts function in young hydrological systems.

We systematically investigated how form and function evolved during the first 10 millennia of landscape development. We analyzed two hillslope choronosequences in glacial forelands in the Swiss Alps, one developed from siliceous and one from calcareous parent material.
Variables describing form were studied in terms of soil properties and vegetation characteristics obtained by vegetation mapping, extensive soil sampling and laboratory analyses. Variables describing hydrologic function include soil water response times, soil water storage, dominant flow path types, and the frequency of preferential flow paths which were obtained by Brilliant Blue dye tracer irrigation experiments and sprinkling experiments with deuterium. A principal component analysis and clustering were used to identify how form features relate to specific functions.

Our investigation revealed differences in the evolution of form and function between the two different parent materials. At the calcareous site, a change in flow types with increasing moraine age was observed from a rather homogeneous matrix flow to heterogeneous matrix and finger-like flow. However, the high buffering capacity of the calcareous soil leads to less soil formation and fast, vertical subsurface water transport dominates the water redistribution even after more than 10 000 years of landscape evolution. At the siliceous parent material accumulation of organic material with high water storage capacity and podsolization was observed between 3 000 and 10 000 years of landscape development. Under these conditions water redistribution is dominated by vertical subsurface water transport via matrix flow only at young age classes (< 3 000 years). After 10 000 years of soil development vertical subsurface water transport below the organic top layer mainly takes place via macropore flow, and water storage in the organic surface layer and lateral subsurface water transport become the major components controlling water redistribution.

We found that in general the increase in preferential flow frequency is caused by soil development and is further enhanced by an increase in above ground biomass, organic matter and micro topography. Form parameters driving the evolution of subsurface function differ between the two contrasting geologies which highlights the importance of the parent material for landscape development.

How to cite: Hartmann, A., Blume, T., and Weiler, M.: Unsaturated subsurface flow: How it evolves in the first 10 000 years after landscape initialization, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4977, https://doi.org/10.5194/egusphere-egu23-4977, 2023.

Stormwater control measures (SCMs) such as retention basins, bioswales, and bioinfiltration systems are used to reduce peak flows and remove pollutants from stormwater in temperate urban landscapes. However, the application of de-icing salts to roadways can substantially increase the salinity of stormwater basin media (i.e., engineered soil), likely impacting the physical properties of these soils. Further, SCM soils can become moderately compacted, potentially altering the extent and effects of salinization on soil physical properties. Although many studies have documented the high salinity of roadside soils in winter, the effects of salinity on soil hydraulic properties is not well understood, especially in the context of urban stormwater basins. Here, we compared the water retention properties (spanning pressure potentials of -10 to -1,000,000 hPa) of salinity-affected stormwater media (1-100 dS m^-1, using Na⁺ and Mg²⁺ salts) that was either uncompacted or compacted. The effects of salinity on both matric and osmotic potential included shifts in the plant-available range with the magnitude depending on a combination of salt type and concentration. We attribute these changes to salinity inducing shifts in both surface tension and pore size distributions. Further, compaction increased the severity of salinization under low salinity conditions but not high. Climate change may increase the number and intensity of snow events in many temperate urban regions, which may increase salt loads to stormwater control measures, exacerbating the aforementioned effects.

How to cite: Archibald, L., Khatei, G., Caplan, J., Van Pelt, S., D’Odorico, P., and Ravi, S.: Compounding Effects of Salinity and Compaction on Hydraulic Properties of Roadside Stormwater Control Measures, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8262, https://doi.org/10.5194/egusphere-egu23-8262, 2023.

With the increasingly negative impact of climate change, there is a significant need for more accurate runoff measurements in steep-sloped catchments to understand and predict the impact of extreme weather conditions. The spatial and temporal variability of precipitation, different soil parameters, soil moisture and infiltration characteristics significantly influence the surface runoff and channel flow processes in natural catchments.

During the last 5 years, the Faculty of Water Sciences of the University of Public Service developed a complex meteorological and hydrological monitoring system at Várvölgyi creek which is a 5.95 km² sub-catchment of Völgységi creek watershed. The small steep-sloped experimental catchment lies on the border of Magyaregregy. This small village located in the eastern Mecsek region in the southern part of Hungary. The research program aims to better understand each runoff process element in the watershed. Five years ago, a meteorological station was installed to improve rainfall measurement accuracy. In addition to meteorological and flow measurements, soil moisture sensors were recently installed at three locations to record soil moisture data at six different depths. In this paper, we investigate the connection between soil water content and streamflow.

The research presented in the article was carried out within the framework of the Széchenyi Plan Plus program with the support of the RRF 2.3.1 21 2022 00008 project.

How to cite: Koch, D., Majer, F. K., Keve, G., and Bene, K.: The connection between soil water content and stream flow in the experimental catchment of Magyaregregy (Hungary), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7887, https://doi.org/10.5194/egusphere-egu23-7887, 2023.

Climate change affects temperate forests particularly by changes in water availability as a result of rising temperatures and changing precipitation dynamics. While the annual mean will remain roughly constant, it is the intensity pattern that will change: light precipitation events decrease and heavy precipitation events increase. Droughts and heat waves are assumed to become more frequent, longer and more intense, also as a feedback mechanism of reduced soil moisture affecting evapotranspiration. In addition to meteorological droughts, edaphic droughts are anticipated to increase in the future. These developments impact the soil hydrological functions with altered infiltration conditions, increased surface runoff and an increasing proportion of preferential flow affecting a more complex and heterogeneous water distribution in the subsurface. Yet the link between tree mortality and the reduced and more heterogenous soil water distribution is still not fully understood

The majority of approaches analysing soil moisture dynamics are based on point measurements, which do not account for the high spatial variability of soil water. Here, we close this knowledge gap by fusing established point-measurements with geophysical methods to assess the spatio-temporal dynamics of water fluxes in the near-surface subsoil from slope to the root zone scale. The questions we ask focus on how infiltration, subsurface water flow, soil moisture distribution and persistence are affected by (i) the subsurface architecture including textural variations as well as preferential flow paths (macro pores, root tracks) and (ii) hydrological extremes (droughts, rain events).

Our study site is located in a beech forest near Ebergötzen (central Germany). The Triassic sandstones are overlain by periglacial slope deposits with varying amounts of loess. The Ebergötzen test site is equipped with numerous sensors for analysing water and element fluxes. In addition to meteorological parameters, we collect 15 min times series of throughfall, stemflow, soil water content, water tension and sap flow. This set-up is ideally suited to quantify water fluxes on a point-by-point basis with high temporal resolution, and to validate complementary, beyond-point approaches. To account for the small-scale variability of processes, geophysical methods with a focus on high-resolution electrical resistivity tomography (Dipole-Dipole, 48 electrodes, 15 cm spacing) were used. Measurements were carried out as a combination of a long-term approach (fortnightly/monthly) and event-based measurements (thunderstorm, round the clock).

Our data indicate a relatively uniform decrease in soil moisture during prolonged dry periods, with root-water uptake locally causing higher dynamics. In contrast, subsurface moisture penetration after precipitation events is spatially highly variable, confirming the importance of preferential flow for infiltration and distribution of water in the subsurface and thus show the high demand for spatially high-resolution measurements of soil moisture dynamics.

How to cite: Schwindt, D., Dietze, M., Birk, J. J., Drollinger, S., Flores-Orozco, A., and Sauer, D.: Spatio-Temporal Water Fluxes in the Slope-Soil-Tree Continuum of a Temperate Beech Forest in central Germany, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14720, https://doi.org/10.5194/egusphere-egu23-14720, 2023.

Apple production is a major agricultural activity in many regions around the globe. Over the past decades, a range of different pesticides have been used for preventing fungal and insect infestations. Evaluating the fate of pesticides in plants and soil is important for determining human health risks arising from chemical residues in fruits as well as ecological risks, among others resulting from pesticide fate in soils and eventually leaching to groundwater.

This study aimed at improving the understanding of complex fate and transport processes interacting in the soil-plant system of an apple orchard. Field experiments were done with different insecticides and fungicides that are frequently applied in agricultural practice. Pesticide concentrations in soil and different plant parts were observed at different times under a multiple pesticide applications scenario.  A coupled soil-plant model was set up for numerically simulating pesticide fate and comparison with observed pesticide concentrations. This model considers a tipping buckets approach for soil water and solute transport, linked with a dynamic numerical model for plant uptake and translocation of chemicals within plants, implementing a fruit growth model for explaining the fruit growth dilution. Moreover, risks posed for food safety were estimated.

This model approach was successful for describing observed pesticide residues. Up to 25% of the applied chemicals were deposited on leaves and up to 0.6% on fruits, and up to 61% entered the topsoil directly after application. A decrease in fruit concentration was observed, which could be explained by biodegradation and growth dilution as the main contributions, as well by wash-off. First estimates of dietary risks indicated that the ingestion of the treated apples may not lead to relevant acute or chronic human health risks. The contribution of the different pathways leading to pesticide residues and their dynamics in plant material was highly influenced by precipitation patterns, fruit growth dilution and pesticide characteristics. Our model approach can contribute to an improvement of process understanding concerning the fate of pesticides in apple orchards and pesticide utilization. It has a high potential for supporting decision making with respect to food safety and minimizing risks associated to pesticide use.

How to cite: Rein, A., An, Q., Wu, Y., Li, D., Hao, X., and Pan, C.: Dynamic modeling of plant uptake and leaching of pesticides applied at an apple orchard, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11736, https://doi.org/10.5194/egusphere-egu23-11736, 2023.

Evaporation from bare soil is an important hydrological process and part of the water and energy balances of land surfaces. Comprehensive modelling of this process must include coupled liquid, vapor and heat fluxes. Model concepts of varying complexity have been proposed to predict water loss from soil through evaporation. The objective of our study was to test a coupled water, vapor and heat flow model with data from laboratory evaporation experiments under different boundary conditions. Laboratory evaporation experiments were conducted with a sand and a silt loam under three atmospheric forcings. Pressure heads, soil temperature and the evaporation rates were monitored and the experiments were simulated with a coupled water, vapour and heat flow model which solves the surface energy balance and predicts the evaporation rates. The evaporation dynamics was well captured, in particular the onset of stage-two evaporation and the evaporation rates during stage-two. A valid description of the observed data required the use of a comprehensive model of the soil hydraulic properties which accounts for water adsorption and film flow. However, a slow continuous decrease in the measured evaporation rate during stage-one could not be described with the model under the assumption of a constant aerodynamic resistance. While the addition of established empirical soil resistance parametrizations significantly degraded model performance, the use of a boundary layer resistance improved the evaporation rate predictions for the sandy soil but not for the silt loam. Care should be taken when using resistance parametrizations in coupled modelling of bare soil evaporation.

How to cite: Iden, S., Blöcher, J., Diamantopoulos, E., and Durner, W.: Validation of coupled water, vapor and heat flow models with evaporation experiments, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11132, https://doi.org/10.5194/egusphere-egu23-11132, 2023.

In recent years, with the development of intensive farming and livestock breeding activities, nitrate contamination of aquifers has occurred. The importance of the unsaturated zone in the study of nitrate percolation is well recognized. The vadose zone represents a fundamental part of the water cycle, capable of storing water, providing water for vegetation, transporting solutes and degrading contaminants before they reach the aquifer.
This research involves two areas with different geological, hydrogeological and pedological properties located in Sardinia. The plain of Arborea has been designated as Nitrate Vulnerable Zone (NVZ) since 2005, but despite the reduction of nitrogen input no significant improvement in water quality has been achieved. In the Southern Campidano plain, an area with an agricultural tradition, significant nitrate concentrations were observed in groundwater.
The main objective of this research is to estimate the groundwater recharge rate using vadose-zone water stable isotope profiles.
Firstly, to understand the dynamics of water percolation through the vadose zone, soil samples were collected at different depths to analyzed for physical properties, including soil-water content, and grain size to estimate soil hydraulic properties. In addition, suction cups were installed at different depths at each site to extract pore water from the soil for chemical analysis.
In hydrological systems, the use of stable isotopes (¹⁸O and ²H) of pore water as environmental tracers is considered the most useful tool for establishing water flow and contaminant transport. In this study stable pore water isotope profiles combined with water content profiles were used to obtain insight into the transit time of water percolating through the vadose zone. At each of the two study sites, vertical soil sampling was made along the vadose zone and the soil samples collected were analyzed for stable water isotope ratios (¹⁸O and ²H) and volumetric water content. Through the seasonal signatures of stable isotopes in leachate water it is possible to quantify possible groundwater recharge, this approach, called the peak-shift method assumes advection-dominated transport.
Analysis of nitrate concentrations in soil water below the root zone using suction cups combined with groundwater recharge rates will allow an estimate of site-specific nitrate leaching. Through this approach, it is possible to evaluate potential and conservative propagation of nitrogen at specific depths to be compared with the concentrations measured to gain information on nitrate transformation processes in the soil.

How to cite: Lobina, F., Da Pelo, S., Stumpp, C., Arras, C., Biddau, R., Coppola, A., and Vacca, A.: The use of stable pore water isotopes in the study of nitrate leaching, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16234, https://doi.org/10.5194/egusphere-egu23-16234, 2023.

We develop an integrated model framework for the simulation of a multitude of soil hydrological processes, such as (reactive) solute transport together with (preferential) water flow and diffusive mixing on the pore scale. This framework is called the Lagrangian Soil Water and Solute Transport (LAST) Model. It bases on a new theoretical concept and should serve as alternative to the common theories of the Darcy-Richards equation and the advection-dispersion-equation (ADE), which have limitations under more natural conditions.

In the LAST-Model framework, soil water is represented by discrete water particles of constant mass. The model applies a Lagrangian perspective on the trajectories of particles through a partially saturated soil domain. Particle displacements along the trajectories are calculated by a non-linear, space domain random walk that combines physics and stochastic. We gradually extend the scope of the LAST-Model framework by additional routines.

We implement routines for solute transport and preferential flow. Water particles are assigned by a solute mass and in this way, solutes are distributed together with the displacement of water particles. For preferential flow, a structural macropore domain is implemented as a second flow domain. Particles can infiltrate and travel purely by gravity in the macropore domain, independent from capillary-flow conditions in the soil matrix. As a result, they can bypass the bulk water fractions in the soil matrix before re-infiltrating the matrix and accumulating in greater depths.

We modify the solute transport routine to allow for the simulation of the transport of reactive substances. Specific routines for sorption and degradation processes are implemented. Sorption is represented by an explicit solute mass transfer between water particles and the solid phase by means of non-linear Freundlich isotherms, and driven by a concentration gradient. Adsorbed solutes are then assumed to be microbially degraded following first-order decay kinetics.

We introduce the diffusive pore mixing (DIPMI) approach as additional routine for the simulation of pore-size-dependent diffusive mixing of water and solutes over the pore space. This approach should produce more reliable descriptions of frequently observed (imperfect) mixing behaviours, in contrast to the common assumption of averaging concentrations over all pore sizes in a single time step.

Each model extension is tested by simulations of field and laboratory experiments as well as sensitivity analyses. Simulation results are compared against observed data and results of a benchmark model that uses the Darcy-Richards theory and the ADE. The most important findings of the studies can be summarized as:

• The structural macropore domain is key for a successful representation of preferential water flow and (reactive) solute transport. In heterogeneous soils, LAST simulations match better the observed redistribution and depth-accumulation of solutes compared to simulations with the Darcy-Richards + ADE model.
• Imperfect, diffusive mixing on the pore scale has a significant influence on macroscopic leaching behaviours and chemical/isotopic compositions of soil water fractions.
• The particle-based approach of the LAST-Model framework is a promising tool for further soil- and ecohydrological application fields.

How to cite: Sternagel, A., Loritz, R., and Zehe, E.: A Lagrangian model framework for the simulation of fluid flow and solute transport in soils, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3205, https://doi.org/10.5194/egusphere-egu23-3205, 2023.

A new numerical method was developed to accurately and efficiently compute a solution of the nonlinear Richards equation with a layered soil. In the proposed method, the Kirchhoff integral transformation was applied. However, in the Kirchhoff integral transformation approach, the transformed Kirchhoff head has dyadic characteristics at the material interface between different soil types. To avoid the dyadic characteristics at the material interface, a truncated Taylor series expansion was applied to the Kirchhoff head at the material interface and so the Kirchhoff head was replaced with a single pressure head value at the material interface. Accordingly, through the Taylor series expansion, a set of algebraic equations in the one-dimensional control volume finite difference discretized system formed a tridiagonal matrix system. Through a series of numerical experiments, the new method was compared to other numerical methods to determine its superiority. The results clearly demonstrated that the approach was not only more computationally efficient, but also more accurate and robust than other numerical methods. Computational performance was greatly enhanced with the proposed method, and which could be used to simulate complicated heterogeneous flow at a large-scale watershed or regional scale.

Acknowledgments

This work was supported by the basic research project (23-3411) of the Korea Institute of Geoscience and Mineral Resources (KIGAM) funded by the Ministry of Science and ICT.

How to cite: Suk, H., Piao, J., Han, W. S., and Kim, S.-K.: Numerically efficient algorithm for simulating variably saturated flow in heterogeneous layered porous media, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5867, https://doi.org/10.5194/egusphere-egu23-5867, 2023.

Catchment-scale hydrological simulations typically require numerical solutions to the Richards equation, which describes variably-saturated water flow in porous media. In recent years, with the widespread use of high-performance computing (HPC), the simulation speed of hydrological models have been significantly enhanced. However, existing numerical schemes for the Richards equation show different performance under different HPC configurations. It remains unclear if the serial Richards solvers scale well in parallel. 

In this work, four popular numerical schemes (the fully explicit scheme, the predictor-corrector scheme, the iterative Picard scheme, and the fully implicit Newton's scheme) are implemented to solve the three-dimensional Richards equation, aiming at investigating the performance of these schemes on both multi-core CPUs and GPUs. The codes are built under the Kokkos framework to achieve performance portability between CPU and GPU. Two infiltration problems with analytical solutions available are chosen to evaluate the model performance in terms of accuracy and efficiency. 

As expected, the simulation results indicate that the optimal solution schemes on CPU and GPU could be different. Moreover, the numerical scheme, the linear system solver, and the soil properties all have influence on scaling. A hybrid scheme is promising for minimizing the computational cost under various simulation conditions. The findings of this work will guide the development of the subsurface flow module of the performance-portable, multi-physics model, SERGHEI.

How to cite: Li, Z., Caviedes-Voullième, D., and Özgen-Xian, I.: GPU-accelerated numerical solution to the Richards Equation:performance and prospects, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5902, https://doi.org/10.5194/egusphere-egu23-5902, 2023.

Ignored until now for their hydrogeological potential, in the conditions of current climate changes, the Sarmatian deposits in the Moldavian Platform, Romania attract the attention of researchers aiming at the objectives of Romania's long-term security strategy. Vital resource, underground water, significantly affected by global climate changes, calls for regional management strategies that must be based on detailed hydrogeological research of storage, recharge and protection conditions under the impact of natural and anthropogenic factors.

Integration of contaminant migration is the current, highly effective approach for evaluation of groundwater resources used as the source of tapping groundwater supplies for a large part of urban and rural agglomerations.

The Sarmatian hydrostructures from the Moldavian Platform, with a high level of vulnerability to pollution, are the subject of our integrated hydrogeological modelling, in which the vadose zone is the main complex objective. Using our Integrated Hydrogeological Modelling we achieved the coupling of the contamination migration from the soil, the vadose zone and the phreatic Sarmatian hydrostructure in several areas (Huși, Vaslui, Botoșani).

The quantitative evaluations carried out on the conceptual 3D models of the SARMATIAN hydrostructures were carried out using the classic tools: ROCKWORKS, SESOIL, VS2DT, MODFLOW.

How to cite: Iojă, A. A. and Scrădeanu, D.: An Integrated Hydrogeological Modelling Approach to Evaluate Groundwater Resources of Sarmatian Hydrostructure from the Moldavian Platform, Romania, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4476, https://doi.org/10.5194/egusphere-egu23-4476, 2023.