NMDE site evaluation dive for Hurricane Bay – November 28, 2013 – Happy Thanksgiving!

Over the past several weeks, the NMDE team divers have endeavored to reach all of our PBTahoe sites.  Today we planned to visit the Hurricane Bay Site.  NMDE divers Martin M. and Marc B.  conducted a dive to the PBTahoe depth benchmark located up-slope from the wreck of the Alley Cat.  This benchmark was set in October of 2012 (see blog post below).  The benchmark should have read well below 60′ as the lake is some 3 feet lower based upon the Lake Tahoe Watermaster data but it read 72′ so we will need to re-establish a better and more accurate depth gauge.  We are not sure if the gauge simply has broken but will do a follow-up dive to assess in the coming months.  The temperature was a brisk 52F based upon the benchmark gauge and the visibility was simply crappy – at best 30 feet but 25′ was the distance we could see on the visibility markers.  We could see the 3 marker but could not make out the #3 upon it.  As we delved deeper into the dive (pardon the pun) we began to notice a possible reason for the low visibility; Zooplankton – Diaptomus specifically!  These little guys are red in color.   Normally, this time of year as the lake temperatures are dropping the Diaptomus populations diminish.  This condition usually happens towards end of August early September but here we are in November and the populations in the 30-40-50 and 60 foot water columns were thicker than we have ever seen them.  We also encountered some dense populations of Mysis Shrimp but the populations were scattered and inconsistent along our 3000′ path.  We did notice lots of juveniles.

Dive time was 65 minutes at a maximum depth of 63 feet with an average depth of 45 feet.

Project Baseline Stats
Depth: 72′ (per benchmark gauge – under evaluation) 57′ per digital FFW depth gauge
Temperature: 52f
Visibility: 20-30 feet (maybe 25-28feet) Could see the 2 and the third marker but not the #3