Water percolation through a clayey vadose zone

S. Baram, D. Kurtzman, O. Dahan

Research output: Contribution to journalArticlepeer-review

62 Scopus citations

Abstract

Heavy clay soils are regarded as less permeable due to their low saturated hydraulic conductivities, and are perceived as safe for the construction of unlined or soil-lined waste lagoons. Water percolation dynamics through a smectite-dominated clayey vadose zone underlying a dairy waste lagoon, waste channel and their margins was investigated using three independent vadose-zone monitoring systems. The monitoring systems, hosting 22 TDR sensors, were used for continuous measurements of the temporal variation in vadose zone water-content profiles. Results from 4years of continuous measurements showed quick rises in sediment water content following rain events and temporal wastewater overflows. The percolation pattern indicated dominance of preferential flow through a desiccation-crack network crossing the entire clay sediment layer (depth of 12m). High water-propagation velocities (0.4-23.6mh -1) were observed, indicating that the desiccation-crack network remains open and serves as a preferential flow pathway year-round, even at high sediment water content (∼0.50m 3m -3). The natural formation of desiccation-crack networks at the margins of waste lagoons induces rapid infiltration of raw waste to deep sections of the vadose zone, bypassing the sediment's most biogeochemically active parts, and jeopardizing groundwater quality.

Original languageEnglish
Pages (from-to)165-171
Number of pages7
JournalJournal of Hydrology
Volume424-425
DOIs
StatePublished - 6 Mar 2012

Keywords

  • Desiccation crack
  • Infiltration
  • Preferential flow
  • Smectite-dominated clay
  • Vadose zone
  • Waste lagoon

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