Infiltrometer History
Soil Physics Memories
Development of the Infiltrometer
By Dr. Walter Gardner
The advert of a new version of the mini-disk infiltrometer motivated Decagon to research the
history of the disk infiltrometer. A search of the soil physics lab at WSU and phone calls to
Dr. Walter Gardner himself resulted in the following story.
"My father was interested in making a large number of field infiltration measurements and
talked to me about building something which could be easily and quickly used. I do not recall
whether or not he described exactly what he wanted or if he left it entirely up to me, as was
his usual practice in working with his students to give them experience. I do know that Edme
Mariotte, who died in 1684, had used the negative head idea for maintaining free liquid
surfaces as was done in the Mariotte flask system bearing his name.
Also, I well remember that in the days when most families in our town kept chickens we used to
put a fruit jar full of water upside down in a tray and to use a small stick to raise one edge
slightly so as to permit a bubble of air to enter and an equivalent volume of water to come
down into the tray. Thus, when this principle was used around my laboratory, instead of
calling it a Mariotte system we called it a "chicken-feeder". I turned out a brass cone on the
lathe and fitted it with a bottom plater perforated with small holes. To supply the air, ala
Mariotte, I connected a small tube with a hole in its center to the edge of the cone,
creating a system whereby a negative head of about 1 cm was created.
I remember testing the instrument in the field and having been skeptical as to its value
because of the 3-dimensional nature of the water flow. I did experiment a little using a
cylindrical guard ring surrounding the device. However, I never was satisfied that I had
created a linear flow system at the center of the flow pattern as I had desired. Shortly
thereafter, I left the University to take a research fellowship with the Central Scientific
Company in Chicago and forgot all about this matter.
About a month ago, I attended a reunion of students who lived before World War II in my old
neighborhood in Logan, Utah. A fellow attending told me that after I left Utah State he was
hired by my father to make infiltration measurements all around Cache Valley using the
instrument. Then, as you know, Gaylon Campbell found the instrument in my WSU laboratory and
began using it. Since soil physics no longer was studied in the Utah State University Physics
Department, in the early 1950's I had found the old instrument in the store room adjacent to
my father's office and I had appropriated it."
It is important to note that Dr. Gardner brought the infiltrometer with him to Washington State University where it was used as the inspiration for Decagon's current design.