Surface water/groundwater interaction in the Piora Aquifer, Switzerland: Evidence from dye tracing tests

Martin H. Otz, Heinz K. Otz, Ines Otz, Donald I. Siegel

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


Results of seven dye tracing tests done from 1993-1997 to investigate the extent to which lakes and surface water interact with the underlying Triassic Piora Aquifer, Switzerland, are reported here. Two of the dye tracing tests showed that groundwater flows in the Piora Aquifer from the Piora Valley to springs in the adjacent Santa Maria Valley, and even further east to the di Campo Valley considerably outside of the Piora Valley surface water divide. Lake Ritom located in the Piora Valley loses water only to the Canaria Valley outside of the lake's surface-water watershed at the lake's western margin when lake levels are above 1,835 m above sea level. Dye tracing tests show that a major sinkhole in the Piora Valley, Calderoni Sinkhole, is located precisely on the water divide where suburface flow in the Piora Valley and surface water diverge and move in opposite directions. The dye tracing results also showed no hydraulic connection between surface water in the Piora Valley and the famous Pertusio Spring, located in the upper Santa Maria Valley. Only a small amount of dye from the two dye tracing tests done in 1993 and 1997 entered an exploratory gallery built to test the viability of the AlpTransit tunnel, being built in competent rock under the Triassic Piora Aquifer, effectively perched above.

Original languageEnglish (US)
Pages (from-to)228-239
Number of pages12
JournalHydrogeology Journal
Issue number2
StatePublished - Apr 2003


  • Dye tracing
  • Lake Ritom
  • Pertusio
  • Piora
  • Surface water

ASJC Scopus subject areas

  • Water Science and Technology
  • Earth and Planetary Sciences (miscellaneous)


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