Thursday, July 12, 2012

This morning when we got to the lab, the cylinder that contained the Duck Creek sand had broken sometime during the night. Due to this unfortunate event we were unable to test that sand today. We did however have another cylinder set up that contained 6 inches of Lake Superior sand on the bottom and 3 inches of F65 sand on top of that. We used the falling head model to obtain our values and calculated our k-values. We then compared the experimental k-values with the k-values we got using Modflow.  Although they were not the exact same, the general trend was there. When the F65 and Lake Superior sand were flipped, the graph had a trend going the other way however the experimental results seemed to more accurately match the k-values obtained from Modflow when the Lake Superior sand was on top. We are not exactly sure why, but David put forth that it might be because the Lake Superior sand seems to settle much better than the F65 sand.

After lunch, we also ran some more tests. This time we set up a single layer of rocks that covered the sand. We then put 6 inches of sand on top of the layer of marbles. We wanted it to try to mimic a layer of rocks in a stream. We started the column a half inch above the rocks and continued to move the column up obtaining our values need to calculate hydraulic conductivity. We will look to compare the k-values we got once we have obtained k-values from running Modflow.
broken cylinder with Duck Creek sand

adding the marble layer

100 marbles in layer

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