Water Conditions Discussion: 4-27-20

Wildlife Drinking Water Availability Update 4/28/2020

On 4/26/2020 the lower Keys finally got some rain! Until then, the last decent rain occurred on 2/27/2020, and a few places got a sprinkle on 3/10/2020. So for most areas it was a solid 2 months with no rain! Here is a quick update on how the new rain likely affected wildlife drinking holes:

From our limited field work yesterday, it is obvious (as was expected) that the rain amount differed considerably with location, and its effect on salinity concentrations thus also varied regionally. The greatest benefit was observed on No Name Key where the downpour was major (we’ll get exact rain data by next week). As we reported earlier this month, prior to the rain event every monitored water hole was either dried up or had the last remnants of water. Presently every water hole is literally filled to the brim! It will be interesting to find out exactly how much rain is needed to go from dry to full capacity on that island.

The rain’s effect in other areas varied from lowering the salinity of existing water holes a little bit, to being negligible. This is likely due to a combination of pre-rain salt concentration, lesser rain volume, and concentration of salt still retained in the ground surrounding each water hole. For example, sampling station BPK9 in central Big Pine Key only went from 15.6 ppt on 4/19/2020 to 14.0 yesterday, despite visibly increased holding volume. BPK12 in southern Big Pine Key went from 13.5 ppt to 13.3 yesterday. So both sites continue to be too salty for extended wildlife use. And the monitored sites on the Long Beach peninsula (some of which were dry last week) continue to have readings well in the hypersaline range (>36ppt). Long Beach got @ 0.8” of rain.

So while the long awaited rain greatly eased-up wildlife drinking water availability for now on No Name Key, it did not change other areas’ conditions. We’ll need considerably more precipitation to register significant changes in water availability.

NNK before and after


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