Category: Ecology

Autumnal pool

The vernal pool we have been monitoring has been dry since about June 17. There were a couple of rainy days in late June, but the puddles formed did not last more than a day. The pool was dry when I visited on July 10, September 29, and October 23. That is, there was no standing water, but the soil under the leaves was always damp. New data from the water depth datalogger indicate that only two rainfall events between June 30 and October 23 produced standing water in the pool.

Figure 1. Vernal Pool NEW370 on September 29, 2020. I swapped batteries and the SD card which had continual data from July 10. That span of 11+ weeks is so far the longest duration on batteries for this datalogger. This image is stitched from 20 photos. Click to embiggen.

Dry, with a twist

It has been three weeks since I last visited the vernal pool and installed the Version 4 (Ultrasonic) water depth data-logger. I was curious to learn whether the new logger was working and decided to collect the data and replace the batteries in both loggers — the Version 3 logger (laser rangefinder) had also been running since the last visit.

Data loggers near the lowest point in the vernal pool and royal fern where six to 10 inches of water are present for much of the year. July 10, 2020.

Venal Pool

Daytime high temperatures in the first half of June in Middlebury are historically in the 70s F, but so far this year half of the days in June have been in the 80s F. Historically in June, Burlington gets 2.5 inches of rain by the 20th, but so far has gotten only 0.4 inches (last year they got 3.8 inches by now). So maybe I should not have been so surprised on Friday to find that our vernal pool was completely dry. Ned and I visited to collect data from the loggers and install a new version of the DIY water depth and water temperature logger. The new logger might not have much work to do for a while.

Figure 1. This clearing in the woods was a vernal pool a couple of weeks ago. Click to embiggen.