Type curve interpretation of late-time pumping test data in randomly heterogeneous aquifers

Shlomo P Neuman, Ayelet Blattstein, Monica Riva, Daniel M. Tartakovsky, Alberto Guadagnini, Thomas Ptak

Research output: Contribution to journalArticle

45 Citations (Scopus)

Abstract

The properties of heterogeneous media vary spatially in a manner that can seldom be described with certainty. It may, however, be possible to describe the spatial variability of these properties in terms of geostatistical parameters such as mean, integral (spatial correlation) scale, and variance. Neuman et al. (2004) proposed a graphical method to estimate the geostatistical parameters of (natural) log transmissivity on the basis of quasi-steady state head data when a randomly heterogeneous confined aquifer is pumped at a constant rate from a fully penetrating well. They conjectured that a quasi-steady state, during which heads vary in space-time while gradients vary only in space, develops in a statistically homogeneous and horizontally isotropic aquifer as it does in a uniform aquifer. We confirm their conjecture numerically for Gaussian log transmissivities, show that time-drawdown data from randomly heterogeneous aquifers are difficult to interpret graphically, and demonstrate that quasi-steady state distance-drawdown data are amenable to such interpretation by the type curve method of Neuman et al. The method yields acceptable estimates of statistical log transmissivity parameters for fields having either an exponential or a Gaussian spatial correlation function. These estimates are more robust than those obtained using the graphical time-drawdown method of Copty and Findikakis (2003, 2004a). We apply the method of Neuman et al. (2004) simultaneously to data from a sequence of pumping tests conducted in four wells in an aquifer near Tübingen, Germany, and compare our transmissivity estimate with estimates obtained from 312 flowmeter measurements of hydraulic conductivity in these and eight additional wells at the site. We find that (1) four wells are enough to provide reasonable estimates of lead log transmissivity statistics for the Tübingen site using this method, and (2) the time-drawdown method of Cooper and Jacob (1946) underestimates the geometric mean transmissivity at the site by 30-40%.

Original languageEnglish (US)
Article numberW10421
JournalWater Resources Research
Volume43
Issue number10
DOIs
StatePublished - Oct 2007

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transmissivity
Aquifers
aquifers
pumping
aquifer
drawdown
testing
well
methodology
Flowmeters
Hydraulic conductivity
graphical method
heterogeneous medium
flowmeter
confined aquifer
flowmeters
test
method
Statistics
hydraulic conductivity

ASJC Scopus subject areas

  • Environmental Science(all)
  • Environmental Chemistry
  • Aquatic Science
  • Water Science and Technology

Cite this

Type curve interpretation of late-time pumping test data in randomly heterogeneous aquifers. / Neuman, Shlomo P; Blattstein, Ayelet; Riva, Monica; Tartakovsky, Daniel M.; Guadagnini, Alberto; Ptak, Thomas.

In: Water Resources Research, Vol. 43, No. 10, W10421, 10.2007.

Research output: Contribution to journalArticle

Neuman, Shlomo P ; Blattstein, Ayelet ; Riva, Monica ; Tartakovsky, Daniel M. ; Guadagnini, Alberto ; Ptak, Thomas. / Type curve interpretation of late-time pumping test data in randomly heterogeneous aquifers. In: Water Resources Research. 2007 ; Vol. 43, No. 10.
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