Thursday, December 16, 2010

What did we catch in the bins?

One of the buried wheelie bins is just visible in the left of the picture. Up to day 40, the 300 mm depth detectors collected water 3 times. Then on day 41, after a few larger irrigation events, the 500 mm detectors collected their first samples. The detectors at 700 mm did not collect water, and there was no water in the bins.

A very large irrigation was applied on day 66 (13 hours or 8.45 littres per dripper or 28 mm averaged over the whole area). This time the 300 and 500 mm detectors collected, and water also started to collect in the bins. We measured drainage of 2.7 mm from the drier side and 18.6 mm from the wetter side.

We did NOT collect ANY water in the detectors at 700 mm depth.

Water must have gone past this depth because we measured water in the 900 mm deep wheelie bins. However none of this infiltrating water could be collected in a FullStop funnel at 700 mm depth. This tells us something about the limitation of the technique. They do not work when placed too deep.

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