Excerpt
For us it was a routine test and demonstration of the preferential flow of water through soil: apply an inch or two of water containing blue food coloring to the soil in a large ring infiltrometer, and begin digging next to the ring with a backhoe as soon as the water had infiltrated. People in our research group had been doing this for over a decade, as had many other researchers elsewhere. However, for the environmental engineers from a state conservation department looking on, this was to be an eye-opening experience.
Conventional wisdom would lead one to expect that the dyed water would have moved maybe 4 to 6 inches deep in the soil following application. However, we all soon saw that water traveling through preferential flowpaths had left a blue dye “calling card” at a depth of 6 feet in the 20 minutes it had taken the backhoe to dig that deep. The common reaction among the engineers was amazement-their training had not included this phenomenon-followed by the realization of the serious implications that preferential flow could have for their work trying to minimize pollutant transport. The experience made us realize that, despite numerous …
Footnotes
Brian K. Richards, Natalia Peranginangin, Tammo S. Steenhuis and Larry D. Geohring work in the Department of Biological & Environmental Engineering at Cornell University in Ithaca, New York.
- Copyright 2003 by the Soil and Water Conservation Society
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