1/28/18 Drinking Water Survey Update

Today we emailed the following to: Key Deer Refuge Management, Texas A&M Scientist and Ecological Services:

Dear All:

As a follow-on to my e-mail last week regarding the distribution of natural water sources with salinities palatable to wildlife on Big Pine and surrounding Keys, I thought you may be interested in additional data from additional areas tested recently by our Save Our Key Deer organization: We more-or-less completed a sweep of No Name Key with additional measurements in its western portion, and so far obtained some measurements in the north and mid-parts of Big Pine Key mainland.  As you can see from the attached graphics, natural water sources available to wildlife on NNK are primarily limited to a few depressions/solution holes in the spatially-limited pine rocklands between the main road and the southern quarry basin (and one small pond south of the quarry). We compared water existence and extent in some of the larger depressions with extremely high resolution aerial photography done at the end of March, 2013, and noted that several depressions that  have held water into March in 2013 are presently already dry, and two with the deepest water have present water extents very close to where they were at the end of March, 2013.  Hence, we believe our statement of caution about this year’s drinkable water availability on NNK is quite valid, unless our very significant rain deficit quickly changes.  As an example, we are attaching a photo pair of one of the depressions as it was photographed by USFWS 2 weeks after Irma vs. its completely dried-out state today.  Using historical imagery as a guide, the other natural, still viable water sources on NNK will likely dry out, even with occasional rainfall, in a month or two at most. We hope you include these findings in your near-future wildlife support activity planning.

Our measurements on the main land-mass of BPK show that wildlife there has various sources of still potable water in multiple areas, although to a limited extent since some – such as brackish water-filled mosquito drainage ditch sections of only a few yards long – are very small and don’t have much of an expected future lifespan.  The freshest water we found, with salinities as low as 1.4ppt (!!), are in small, narrow but potentially deep solution holes south of Big Pine Street.  Logically, that area corresponds to near the pinnacle location of BPK’s northern freshwater lens, as measured, for example, by Geoview Inc. (http://www.geoviewinc.com/case-studies/geologicalgeotechnical/mapping-freshwater-aquifers ).  A consideration for wildlife is, however, that the openings to these holes are very small (usually <1’) and the water surface is as much as 1.5’ below with vertical walls, so is not reachable to most animals in most (but fortunately not all) cases.  Unlike on NNK, we found all larger, more open depressions that we are aware of in that area to lack standing water at this time (although several of them have remained viable in previous years).  Further south on BPK we tested several water sources on private properties in one region that include man-made ponds dynamited out of the limestone in the 60s and 70s, and natural depressions, sometime enhanced. All contain very wildlife-potable water and most at salinities below 7ppt.

As per our communication last week, in addition to keeping a very close eye on NNK, we urge you to consider most seriously and urgently the water situation along BPK’s Long Beach Rd. – an area that has lost many deer to the hurricane and once again presently has no natural sources of wildlife-potable water that can be located.  We expect a similar situation to exist for wildlife on Big Munson/Little Palm islands which we intend to sample this week. (We have been informed that workers repairing the Little Palm Island Resort have been providing water to 6-7 thirsty deer that visit from neighboring Big Munson.) We also intend to sample additional BPK areas, and islands down to Sugarloaf Key – the westernmost extension of the present Key Deer habitat.  We will provide you with the sampling results as soon as they are available, and as always are open to any cooperation and assistance to the Refuge.


Dr. Jan Svejkovsky

SOKD Treasurer

xNNK Salinity 1_23_28_2018Middle BPK Salinity 1_26_2018Upper BPK Salinity 1_26_2018NNk depression before and after Irma

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