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The seismic stability analysis of slopes is frequently analyzed using the method of slices based on the pseudostatic approach. However, the time response analysis is considered to be one of the most competent tools to analyze the performance of slopes under seismic motion since this method provides details about deformation and stress distribution within the slope. In this paper, a finite-element-based time response analysis was performed to examine the seismic response of an existing hill slope located in the Kavalappara (11.414° N, 76.237° E) region of Kerala, India, where the shear strength of many slopes reduces considerably due to heavy rainfall. In this regard, a synthetic acceleration time history was developed from site-specific seismic hazard analysis. Also, a pseudostatic analysis based on the finite-element method was performed to estimate the factor of safety and corresponding stability measure. The finite-element model was developed based on Mohr-Coulomb and hardening soil with small stiffness (HSsmall) constitutive models to capture the soil behavior during an earthquake. Further, Newmark's sliding block analysis was conducted analytically to study the probable displacement after the seismic event and to validate the present finite-element analysis results. The pseudostatic analysis revealed that the slope is not safe against a pseudostatic loading of 0.12g. The seismic response of the slope under earthquake motion was described via displacement developed due to ground shaking. The results of time response indicated a continuous forward and downward earthquake-induced movement of the slope crest. The maximum displacement observed during the seismic event was 18.84 mm. Further, a sensitivity analysis was performed by considering Newmark's method and a few well-known empirical methods to check the variation of FS values with yield acceleration. Displacement and factor of safety values calculated using analytical methods were in good agreement with that obtained from finite-element-based time response analysis. Moreover, it has been concluded that there is potentially unstable slope condition exists due to combined groundwater variations and earthquake impact. [ABSTRACT FROM AUTHOR]

Event based rainfall-runoff simulation is very important in water resources management. In this paper, an integrated watershed model considering important hydrological processes has been presented for the event based runoff simulation. Green-Ampt-Mein-Larson model has been used for the estimation of infiltration. For runoff estimation, kinematic wave equations are solved for a channel network using finite-element method. Remotely sensed data have been used for evaluating land use/land cover data. Geographical information systems have been used for the preparation of digital elevation model and various thematic maps. The developed integrated model has been applied to Harsul watershed in India. Calibration of the model has been carried out using six rainfall events and validation with four rainfall events. From the results, it is seen that the model is able to simulate the hydrographs with reasonable accuracy. A sensitivity analysis of the model has also been carried out. The developed model is useful for runoff estimation in small watersheds. [ABSTRACT FROM AUTHOR]

The optimal design of a groundwater remediation system using the pump-and-treat method is a complex task involving modeling physical phenomena such as groundwater flow and contaminant transport and optimizing several goals of concern, while satisfying bounds on certain parameters. Simulation tools such as the finite-element method (FEM) coupled with optimization tools such as the genetic algorithm (GA) has been found to be an efficient and easy to use methodology to solve such arduous problems. In this study, a simulation model using the FEM for groundwater flow and contaminant transport has been developed and coupled with a multiobjective optimization model based on the nondominated sorting genetic algorithm II (NSGA II). The model is used to minimize the cost optimization function as well as the time period for the remediation of the aquifer subject to bounds on pumping rates, groundwater heads, and concentration levels of the contaminant. The coupled FEM-NSGA II model has been applied for the remediation of a real field aquifer near Vadodara, India for a combination of flushing and pumping to demonstrate the effectiveness of the proposed multiobjective technique for achieving the optimal pumping policy. Total dissolved solids are considered to be the main pollutant. Three alternative remediation design scenarios with different pumping well locations have been compared and the best remediation design scenario has been identified to be the one that gives the best Pareto-optimal front. The FEM-NSGA II in general evolves a set of well-spread and consistent Pareto-optimal solutions, which represent the best designs that identify the trade-off between the expected cost and the time period of remediation for all the remediation design scenarios while satisfying the constraints, thus, giving the decision maker a wide set of choices. [ABSTRACT FROM AUTHOR]