|Jessica, David, and Matt collect falling head hydraulic conductivity data.|
Tuesday, June 26, 2012
Today we started doing falling-head tests. We began with "play sand" as the cheapest and easily replaced sand, but this was an absolute disaster. We don't know why the water wouldn't flow through the play sand, but it simply stopped. It also dirtied the water, so we have a hypothesis that it has a significant amount of fine particles, that are clogging the tube... This was unexpected and quite worrisome at the time. The complete halt in the falling water remains a mystery, but unknowns are what make it research, right?
We then switched to the sand from Ottawa, IL (F-60?) These runs worked much better. Students are currently investigating the effect of the vertical location of the column (How close to the bottom can it be? How far into the sand does it need to be?) The intent is to figure out some general guidelines on column placement to be used later in more heterogeneous conditions. We also want to find out now if there are general set-up changes that we should make to get consistent results before the system gets more complicated. We should find out more tomorrow...