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Growing human demands are placing significant pressure on groundwater resources, causing declines in many regions. Identifying areas where groundwater levels are declining due to human activities is essential for effective resource management. This study investigates the influence of land use and land cover, crop types, and precipitation patterns on groundwater level trends across the Mississippi River Watershed (MRW), USA. Groundwater storage changes from 2003 to 2015 were estimated using data from the Gravity Recovery and Climate Experiment (GRACE) satellite mission. A spatiotemporal analysis was conducted at four scales: the entire MRW, groundwater regimes based on groundwater level change rates, 31 states within the MRW, and six USGS hydrologic unit code (HUC)-2 watersheds. The results indicate that the Lower Mississippi region experienced the fastest groundwater decline, with a Sen's slope of −0.07 cm/year for the mean equivalent water thickness, which was attributed to intensive groundwater-based soybean farming. By comparing groundwater levels with changes in land use, crop types, and precipitation, trends driven by human activities were identified. This work underscores the ongoing relevance of GRACE data and the GRACE Follow-On mission, launched in 2018, which continues to provide vital data for monitoring groundwater storage. These insights are critical for managing groundwater resources and mitigating human impacts on the environment. [ABSTRACT FROM AUTHOR]

The present mathematical model is solved for the study of the effect of vertically aligned cracks present in the elastic half space on the propagation of elastic waves through the interface between double porosity solid and cracked elastic solid. Local fluid flow (LFF) between the inclusions (second fluid) and the host medium (first fluid) has been considered in double porosity solid which is possible due to wave propagation. This study follows Snell's law for reflection and refraction of an incident wave at the interface. Due to the presence of cracks in elastic half space, a loose bonding at the interface between these two media has been considered which is represented here as tangential slip. Final equation is framed in the form of Christoffel equation, which is solved analytically and found four reflected waves (three longitudinal body waves and one transverse body wave) and two refracted waves (one longitudinal body wave and one transverse body wave). The phase velocities and attenuation coefficients are calculated for each inhomogeneous wave. The expression of reflection and refraction coefficients, and energy shares of each of the reflected and refracted waves for a given incident waves is found in closed form. Numerical examples have been considered to discuss the effect of crack density, aspect ratio, local fluid flow, shear consolidation parameter and loose bonding parameter, etc. on energy shares by reflected and refracted waves. [ABSTRACT FROM AUTHOR]

The present study is focused on the numerical investigation in time domain of the deformation in thermoelastic material with one relaxation time (Lord and Shulman theory) with voids under dependence of modulus of elasticity and thermal conductivity on reference temperature. For dependency on reference temperature, we have taken two cases: (i) linear case and (ii) quadratic case. For numerical investigation, the finite element method with eight-/nine-noded isoparametric finite elements has been used. The results demonstrate that finite element method can reliably predict the deformation of the medium. Finite element method has an advantage over Laplace/Fourier transformation as the equations are solved directly in the time domain, but in Laplace/Fourier transformation, numerical inversion is quite complicated with possible errors. The comparison of these two cases has been discussed in result and discussion section for the temperature distribution, the displacement component, volume fraction field and the stresses. A comparison of Newmark method and Galerkin's method for time domain has been given though three-dimensional graphs. An appreciable effect of thermal relaxation times t0 is observed from the various results. [ABSTRACT FROM AUTHOR]