Predicting conductance due to upconing using neural networks

Emery A. Coppola, Charles F. McLane, Mary M. Poulton, Ferenc Szidarovszky, Robin D. Magelky

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Artificial neural networks (ANNs) were developed to accurately predict highly time-variable specific conductance values in an unconfined coastal aquifer. Conductance values in the fresh water lens aquifer change in response to vertical displacements of the brackish zone and fresh water-salt water interface, which are caused by variable pumping and climate conditions. Unlike physical-based models, which require hydrologic parameter inputs, such as horizontal and vertical hydraulic conductivities, porosity, and fluid densities, ANNs can "learn" system behavior from easily measurable variables. In this study, the ANN input predictor variables were initial conductance, total precipitation, mean daily temperature, and total pumping extraction. The ANNs were used to predict salinity (specific conductance) at a single monitoring well located near a high-capacity municipal-supply well over time periods ranging from 30 d to several years. Model accuracy was compared against both measured/ interpolated values and predictions were made with linear regression, and in general, excellent prediction accuracy was achieved. For example, although the average percent change of conductance over 90-d periods was 39%, the absolute mean prediction error achieved with the ANN was only 1.1%. The ANNs were also used to conduct a sensitivity analysis that quantified the importance of each of the four predictor variables on final conductance values, providing valuable insights into the dynamics of the system. The results demonstrate that the ANN technology can serve as a powerful and accurate prediction and management tool, minimizing degradation of ground water quality to the extent possible by identifying appropriate pumping policies under variable and/or changing climate conditions.

Original languageEnglish (US)
Pages (from-to)827-836
Number of pages10
JournalGround water
Volume43
Issue number6
DOIs
StatePublished - Nov 1 2005

ASJC Scopus subject areas

  • Water Science and Technology
  • Computers in Earth Sciences

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    Coppola, E. A., McLane, C. F., Poulton, M. M., Szidarovszky, F., & Magelky, R. D. (2005). Predicting conductance due to upconing using neural networks. Ground water, 43(6), 827-836. https://doi.org/10.1111/j.1745-6584.2005.00092.x