Probabilistic analysis of groundwater contamination using first and second order reliability methods

Published
2017-05-10
DOI: https://doi.org/10.14295/ras.v31i2.28803
Keywords: Contaminant transport. Probability of exceedance. FORM. SORM. MCS. Transporte de contaminante. Probabilidade de excedência. FORM. SORM. SMC.

    Authors

  • Vanessa Almeida de Godoy Universidade de São Paulo, Departamento de Geotecnia
  • Gian Franco Napa-García Instituto Tecnológico Vale

Abstract

This paper shows an example of the application of the estimation of the probability of a contaminant exceeding a specified maximum concentration (probability of exceedance, Pf) using first order (FORM) and second order (SORM) reliability methods for several initial concentrations and analysis times of 5 and 10 years. The validity of the results was evaluated comparing the obtained results of FORM and SORM with those of Monte Carlo Simulation (MCS). For the same initial concentration, Pf increased with increasing time. For both analysis times (5 and 10 years) and applied methods, Pf tends to increase with the increase in the initial concentration. The comparison between the values of Pf obtained with FORM and SORM and with SMC shows that from 50 μg/L of initial concentration SMC and FORM have very close Pf values. The values obtained with the SORM were close to those resulting from the SMC only for the initial concentrations of 50 and 100 μg/L. The proximity of the Pf values obtained with SMC and FORM indicate that the use of this reliability method is useful in obtaining the Pf, besides being a faster way than the SMC.

How to Cite
Godoy, V. A. de, & Napa-García, G. F. (2017). Probabilistic analysis of groundwater contamination using first and second order reliability methods. Águas Subterrâneas, 31(2), 119–129. https://doi.org/10.14295/ras.v31i2.28803