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Hydrogeology
Published in Mohammad Albaji, Introduction to Water Engineering, Hydrology, and Irrigation, 2022
The groundwater flow equation is a mathematical relationship in differential equation form, which is used in hydrogeology to describe the movement of groundwater in the porous media. The groundwater flow is analyzed by coupling transport law (Darcy's law) and mass conservation law (continuity equation) with the specified initial and boundary conditions. The Laplace equation and diffusion equation are used to describe the steady-state flow and the transient flow, respectively.
Mathematical Modeling to Evolve Predevelopment Management Schemes: A Case Study in Boro River Valley, Okavango Delta, Botswana, Southern Africa
Published in M. Thangarajan, Vijay P. Singh, Groundwater Assessment, Modeling, and Management, 2016
Equation 13.1 describes groundwater flow under nonequilibrium conditions in a heterogeneous and anisotropic medium, provided the principal axes of hydraulic conductivity are aligned with the x–y Cartesian coordinate axes. The groundwater flow equation together with specification of flow and/or initial head conditions at the boundaries constitutes a mathematical representation of the aquifer system. Numerical methods are used in general to solve the groundwater flow equation.
Water Resources Engineering
Published in P.K. Jayasree, K Balan, V Rani, Practical Civil Engineering, 2021
P.K. Jayasree, K Balan, V Rani
The groundwater flow equation is the mathematical relationship which is used to describe the flow of groundwater through an aquifer. The transient flow of groundwater is described by a form of the diffusion equation, similar to that used in heat transfer to describe the flow of heat in a solid (heat conduction). The steady-state flow of groundwater is described by a form of the Laplace equation, which is a form of potential flow and has analogs in numerous fields.
Analysis of groundwater age and flow fractions for source-sink assessments
Published in ISH Journal of Hydraulic Engineering, 2022
Nitha Ayinippully Nalarajan, Suresh Kumar Govindarajan, Indumathi M. Nambi
The conceptual model of the two-dimensional (2D) simulation domain and boundary conditions is shown in Figure 1. The solution to the groundwater flow equation (Equation (1)) gave the hydraulic head distribution. The present work adopted the capture fractions (Potter et al. 2008) to delineate the well capture zone. Hence, the cell-by-cell velocities were calculated from the Darcy equation, and the intercell flows were used for determining the capture fractions (CF). CF gives the portion of cell outflow that eventually contributes to the well. CF calculations start from the sink cell and were obtained from the ratio of total outflows from the cell to its total inflows (CF = qout/qin). The isopleth map of CF was plotted and delineated the well capture zone. The groundwater age equation (Equation (2)) was then solved to yield the groundwater age distribution. Figure 2 encapsulates the adopted methodology.
Using MODFLOW/MT3DMS and electrical resistivity tomography to characterize organic pollutant migration in clay soil layer with a shallow water table
Published in Environmental Technology, 2021
Chang Gao, Xiujun Guo, Shuai Shao, Jingxin Wu
The governing equation used in our study is a standard transient three-dimensional groundwater flow equation [18]: where h is the groundwater head (m), , , and represent the values of hydraulic conductivity (m/d) along the , , and coordinate axes, respectively, W represents the amount of water in or out of a unit volume of aquifer per unit time (d−1), is the specific storage of the aquifer (m−1), and is time (d).
Insight into sea water intrusion due to pumping: a case study of Ernakulam coast, India
Published in ISH Journal of Hydraulic Engineering, 2021
S. K. Pramada, K. P. Minnu, Thendiyath Roshni
Coastal aquifers constitute a major source of fresh water in many countries especially in arid and semi-arid zones. Due to heavy urbanization and industrialization, many coastal areas in the world are highly dependent on local fresh groundwater resources. Hence, for the need of more fresh water, extensive exploitation of groundwater resources in the coastal aquifer is seen. One of the most important threats to groundwater in coastal areas is seawater intrusion due to excessive pumping. Problems of seawater intrusion in coastal areas have attracted considerable concern in many countries. Two general approaches were used to analyze saltwater intrusion in coastal aquifers namely the ‘disperse interface approach’ and ‘sharp interface approach’. The disperse interface approach explicitly represents a transition zone or a mixing zone of the freshwater and saltwater within an aquifer due to the effects of hydrodynamic dispersion (Huyakorn et al. 1987; Putti and Paniconi 1995; Nobi and DasGupta 1997; Cheng and Chen 2001; Tejeda et al. 2003). The second approach is based on the simplification of the thin transition zone relative to the dimension of the aquifer (Essaid 1990; Mahesha 1996). In this approach, the freshwater and saltwater are considered to be two immiscible fluids of different densities. The studies based on this approach are modeled by only solving the groundwater flow equation.