Thursday, September 27, 2007

Rachel at the Red Fox Bridge in Tryon Creek State Park.














The picture below shows how we measure the depth of the water.
We measure from the top of the lowest rail down to the water surface.


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Wednesday, September 26, 2007

The measurement methods

Rachel showing the fern leaves that we used to measure the speed of the stream flowing under the bridge. After dropping the leaves in the water, we recorded the time it took a leaf to float under the bridge. We did this 3 times and took the mean to get a more accurate estimate of the speed at which the stream is flowing.







(Below) Rachel measuring the depth of the water by measuring the distance from the first rail of the bridge down to the surface of the water. We also measured the distance to the bottom of the creek bed. Using these two measurements we can calculate the depth of the water by subtracting the distance to the surface from the distance to the creek bed.
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