Evaluation of streambed hydraulic conductivity heterogeneity in an urban watershed

Robert J. Ryan, Michel C. Boufadel

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

It has long been understood that streambed hydraulic conductivity plays an important role in surface-subsurface solute exchange. Using a portable falling head permeameter in situ, we estimated the horizontal hydraulic conductivity, K, of the near-surface streambed sediments at a total of 85 locations encompassing two depth intervals: 7.5-10 and 10-12.5 cm. The measurements were conducted in an 80 m reach of Indian Creek, a small urban stream in Philadelphia, PA, USA. We found that the ln K data within each sediment layer were Gaussian, but the combined data set was not. The results indicated that while the mean hydraulic conductivity decreased with depth, horizontal heterogeneity (e.g. the variance) increased with depth. This strong contrast between layers suggests that they should be treated as separated entities in modeling studies. Variogram analyses across the stream suggested symmetry with respect to the thalweg in the upper layer and fractality in the lower layer. The variograms along the streams suggested that the K data are random.

Original languageEnglish (US)
Pages (from-to)309-316
Number of pages8
JournalStochastic Environmental Research and Risk Assessment
Volume21
Issue number4
DOIs
StatePublished - Apr 1 2007
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Environmental Chemistry
  • Water Science and Technology
  • Safety, Risk, Reliability and Quality
  • Environmental Science(all)

Keywords

  • Hydraulic conductivity
  • Indian Creek
  • Streambed heterogeneity

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