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Groundwater Planning and Management
Published in Mohammad Karamouz, Azadeh Ahmadi, Masih Akhbari, Groundwater Hydrology, 2020
Mohammad Karamouz, Azadeh Ahmadi, Masih Akhbari
The groundwater flow was simulated using the groundwater modeling system software. The water table and the groundwater quality were simulated using MODFLOW and modular transport, 3-dimensional, multi-species model (MT3DMS), respectively. First, a conceptual model was developed by defining the position and specification of the study area, and the aquifer area was divided into a network of 1000 × 1000 grids. The groundwater simulation model was calibrated for the Bad-Khaledabad region using the data from June 22, 2011, to September 22, 2013. A part of this period is used for modeling the steady flow, and the rest are used for the transient flow in 24 monthly steps. Salinity as a water quality variable is simulated, and its impacts on the crop yields are considered.
Characterizing groundwater quality and seawater intrusion in coastal aquifers of Nagapattinam and Karaikal, South India using hydrogeochemistry and modeling techniques
Published in Human and Ecological Risk Assessment: An International Journal, 2019
S. Gopinath, K. Srinivasamoorthy, K. Saravanan, R. Prakash, D. Karunanidhi
The SEAWAT code, proposed by Guo and Bennett (1998), was applied to simulate the seawater incursion into the coastal aquifers. The current SEAWAT program (Bear 2005; Langevin 2003) uses the altered MODFLOW description (McDonald and Harbaugh 1988) to solve the variable density groundwater flow equation and MT3D to solve the solute transport equation. For the reduction in density and runtimes the SEAWAT codes uses one step interval between flow and transport. In SEAWAT model the MT3D component simulates for a specific time step tracked by MODFLOW (Harbaugh et al.2000) and also calculate the density of groundwater. In the next step, keys from the MODFLOW are developed by MT3DMS (Zheng and Wang 1999) to solve the transport equation. For maximum simulations, one step lag ensures minimum error and if error is noted it can be reduced by shortening the time step length utilized to stimulate groundwater. The purpose of choosing SEAWAT code is due to efficiency of MT3D to solve the mass transport equations which is attempted by method of characteristics (MOC) approaches due to its efficiency in decreasing numerical dispersal. Additional benefit of using SEAWAT is that it uses the worldwide suitable modeling programs including MODFLOW and MT3D.
Synergy of climate change and local pressures on saltwater intrusion in coastal urban areas: effective adaptation for policy planning
Published in Water International, 2018
A. Safi, G. Rachid, M. El-Fadel, J. Doummar, M. Abou Najm, I. Alameddine
For model verification, salinity data collected during a 2013/2014 groundwater monitoring campaign were used (Rachid, El-Fadel, Alameddine, & Abu Najm, 2015). A steady-state MT3D model coupled with the steady-state head results of MODFLOW for June 2012 was run using the standard finite difference method with central-in-space weighting scheme through SEAWAT. The purpose of this steady-state simulation was to adjust the salinity distribution with the hydraulic head to estimate the initial saltwater wedge profile that would exist in the system prior to stressors (Figure 3). The salinity distribution was derived through kriging interpolation using 91 salinity measurements (in the range of 416–21,485 mg/L) collected during the groundwater monitoring programme. However, the salinity data were not sufficiently detailed to delineate a three-dimensional distribution within the aquifer. Since the vertical distribution was not known, the two-dimensional distribution was interpolated with the initial saltwater wedge profile (in 2012) produced by forecasting a historical model (which represents the water level in 1969) out to 2012 (the present water level). The saltwater–freshwater interface associated with the historical model was assumed to be under the non-intrusion condition when saltwater and freshwater were in balance.
Simulation of seawater intrusion and optimization of cutoff wall schemes based on surrogate model
Published in Human and Ecological Risk Assessment: An International Journal, 2019
Tiansheng Miao, Wenxi Lu, Jin Lin, Jiayuan Guo, Yue Fan
According to the above mathematical model, it is simulated using a variable density SEAWAT code (Survey Modular). The SEAWAT code is variable density calculation software based on the MODFLOW code and the MT3D code (Langevin et al. 2003; Zheng and Wang 1999). The simulation results of the software are shown in Figure 3.