Parameter estimation for a karst aquifer with unknown thickness using the genetic algorithm method

Chengpeng Lu, Longcang Shu, Xunhong Chen, Cheng Cheng

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The thickness of an aquifer (B) is a critical hydrogeologic parameter in understanding groundwater system, especially in a karst aquifer where the high heterogeneity in this parameter brings more uncertainty to the evaluation of groundwater resources. In this study, the genetic algorithm (GA) method was used to estimate B, as well as five other parameters, including Kr (horizontal hydraulic conductivity), Kz (vertical hydraulic conductivity), S (storativity), Sy (specific yield), and α (delayed coefficient) of a karst aquifer based on a pumping test. The search bounds of the six parameters for the GA method were obtained from numerous hypothetic numerical tests. The feasibility of the GA method for parameter estimation was verified by the results obtained from the gradient method in terms of a pumping test conducted in the Platte River valley in Nebraska. Then, this approach was used to estimate the hydraulic parameters in a karst aquifer with unknown aquifer thickness based on a pumping recovery test conducted in the Houzhai karst basin, southwestern China. The results show that the Kr, Kz, and the anisotropy ratio of Kr to Kz are strongly affected by B. The differences between the estimated parameter values at two observation wells indicate the existence of high heterogeneity in the karst aquifer. The parameter B has the highest absolute normalized sensitivity among these variables, implying that the estimated B may be more reliable as compared to other parameters. This study demonstrates that the GA method is an alternative method of parameter estimation with the unknown aquifer thickness.

Original languageEnglish (US)
Pages (from-to)797-807
Number of pages11
JournalEnvironmental Earth Sciences
Volume63
Issue number4
DOIs
StatePublished - Jun 1 2011

Fingerprint

Aquifers
karsts
genetic algorithm
Parameter estimation
aquifers
karst
Genetic algorithms
aquifer
pumping
methodology
groundwater
testing
Groundwater resources
Gradient methods
Hydraulic conductivity
method
parameter estimation
parameter
hydraulic conductivity
groundwater resource

Keywords

  • Anisotropic ratio
  • Aquifer heterogeneity
  • Aquifer thickness
  • Genetic algorithm
  • Karst aquifer
  • Search bounds

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Water Science and Technology
  • Soil Science
  • Pollution
  • Geology
  • Earth-Surface Processes

Cite this

Parameter estimation for a karst aquifer with unknown thickness using the genetic algorithm method. / Lu, Chengpeng; Shu, Longcang; Chen, Xunhong; Cheng, Cheng.

In: Environmental Earth Sciences, Vol. 63, No. 4, 01.06.2011, p. 797-807.

Research output: Contribution to journalArticle

Lu, Chengpeng ; Shu, Longcang ; Chen, Xunhong ; Cheng, Cheng. / Parameter estimation for a karst aquifer with unknown thickness using the genetic algorithm method. In: Environmental Earth Sciences. 2011 ; Vol. 63, No. 4. pp. 797-807.
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