Wednesday, May 25, 2016

Studying water flows at the rain garden

We had another adventurous day in the field this morning followed by some lectures after lunch.
The morning was spent back at the rain garden, where the Trondheim fire department joined us. Using their firehose, they flooded the area right in front of the inflow (where runoff would flow into the garden if there happened to be a heavy rainfall) of the rain garden.

When the water began to flow into the rain garden, we started taking measurements of the water height above the weir (a V-notch cut out of a steel plate used to control the rate at which water flows into the garden). We will compare the measurements that we took to the measurements taken by a pressure gauge at the site in order to determine its accuracy.

After we had taken enough data, the fire department turned up the water flow out of the hose to completely fill the rain garden. There may have been a little mishap... no one was holding the hose down; when the pressure in the hose increased, it flung to the side, dousing half our group.

After the garden was filled we took the same type of measurements for the rain garden's outflow weir and the overflow weir. We returned to the classroom, where we had lunch. We all got to try a common Norwegian staple, Lefse, but it came prepackaged; I think we do it better in Minnesota. Then, we returned to the classroom to receive a lecture to prepare us for labs tomorrow.