New Millennium Divers Parker and Martin M. were able to take an early out from work on this Wednesday afternoon and assess the Patton Beach station. Conditions were superb, flat water, minimal boat activity, sunny and in the mid 70's. Previous weather patterns have been calm.
The animal life was scarce with the exception of crayfish feeding on recently discarded fish carcasses from the local sport fishing operations at the nearby marina. The presence of Diaptomus and Mysis Shrimp were non existant - a stark contrast from our January 1, 2014 dive. The lake was very calm and clear.
Project Baseline Statistics
Depth: 35' per benchmark gauge - 30' and 32' per digital gauges on divers
Visibility: 50-60 feet on the near side of 50
Temperature: 50F on all gauges
New Millennium Divers Todd K and Martin M took advantage of a cold and snowy day (that was not forecast) to enjoy a Project Baseline: Tahoe dive to the Sand Harbor station. It was a great dive out to the outer wall structure and ran 70 minutes at a max depth of 101 feet with an average depth of 49 feet but the most significant visual of this day was the water level never before seen by either divers in over 30 years of diving Lake Tahoe. Please watch this 24 second video, it tells the entire story...
The level of Tahoe is now below its natural rim and to put some perspective to this image, in 31 months, July 2011 to February 2014 the lake has dropped some 5 feet as calculated from the data gathered by the Project Baseline conservation initiative presently underway in Tahoe. In July, 2011 our Project Baseline depth benchmark read 25/26 feet and on Sunday February 2, 2014 it read 20 feet. In a lake with 191 square miles of surface area this 5 foot drop equates to approximately 200 billion gallons of water!
The divers did not observe any Diaptomus (zooplankton) or Mysis Shrimp on this dive. Unlike the New Years day dive at the Patton Beach station where they were quite populace.
Project Baseline Statistics
Depth: 20' per benchmark gauge/17' per digital gauge (FFW)
Visibility: 40-50 feet approaching 50'
Temperature: 44f per benchmark gauge/44f per digital gauge
Photo: Taken 5 October 2013 ( Just to the left of the depth benchmark )
On January 1, 2014, New Millennium divers, Michael S. and Martin M. planned a dive to see how the recent massive high pressure sitting over Northern Nevada since December 3rd, would affect Tahoe's visibility and water conditions. Also knowing that the Limnologists from Wright State University in Ohio are still needing rock/algae samples from 20, 25 & 30 meters, NMDE felt that a solid mission could be formed and executed.
Arriving at the lake, the water was mirror flat. There was no wind, blue skies and upon arrival the air temperature was 24f at waters edge. A perfect day. Upon departure at noon, the conditions were the same and the temperature was 48f. The high for the day was 51f. Incredible for January 1st!
There were two objectives for this dive. First to evaluate the conditions at the Project Baseline station and second to retrieve rock/algae samples from 20, 25, & 30 meters. A secondary objective was to make sure the line to the FISH was still intact after its reestablishment during a previous dive.
The plan was to enter water, doubles and scooter, head to the line leading to the "FISH", evaluate the station then take a 150degree bearing and scooter out to 90 feet - US divers are not very good with the metric system...90 feet is close enough to 30 meters, right? Once at depth, rock samples would be collected then a bearing change to 240 degrees for 2 minutes and then another bearing change to 330 degree back toward the beach collecting rock samples along the way at 75 feet and 60 feet.
Entry was at 9:50am and exit was 11:20am with a total runtime of 71 minutes at a maximum depth of 96 feet (average depth was 54 feet). Scooter speed at approximately 125feet/min.
Upon entry and descent the line was completely intact all the way to the PBTahoe station located at the FISH. Descent was at 5 feet and it took 12 minutes to scooter to the FISH. Evaluations were made and recorded in the wetnotes. The "high pressure" system seems to have no benefit upon the visibility as we could see 30 feet and make out the 40 foot marker but could not see clearly the "4". This is consistent with the past 2 dives.
Continuing it took another 15 minutes to reach the planned depth of 90 feet. The biggest realization was the thickness and volume of Mysis Shrimp at 45 feet on the way out. From the beach to 45 feet they were not being looked for, however it was obviously recognized that as the depth increased, there was still a high concentration of Mysis Shrimp but diminishing all the way to 90 feet. As a result, the divers turned their evaluation to the water column to determine the concentration of Diaptomus (Zooplankton) which was also incredibly high. Higher than remembered for this time of year. A heightened awareness began and it was again observed that from depth back to 45 feet the concentrations of Mysis Shrimp increased and then decreased as the divers continued shallower. At about 15 feet, the Mysis Shrimp were very scarce as well as the Diaptomus. At 45 feet the bottom was completely covered. It was an unreal site and extremely difficult to photograph - Mike tried. Diagram of Lake Tahoe animal species. With the exception of crayfish, no other animal species were seen.
Here is a 44 second video clip of the Patton Beach, Project Baseline Tahoe, station. This will provide a very clear understanding of how the scientifically consistent baseline data is obtained for each site:
PBTahoe Stats:
Depth: 34 feet (30ffw per a digital gauge)
Temp: 50f (46f per a digital gauge)
Visibility: 20-30 feet
Photo: (A standard photo was not taken due to the last dive being so recent, 15 November, 2013.)
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
Photo:
Visibility markers extending east from the Depth Benchmark directly in front of the "Fish" (image below). Benchmark seen in the lower left corner of photo below.
Photos Courtesy of Michael Soldwisch - Member NMDE
Divers Brian P. and Mike S. (the latter a member of NMDE) took the opportunity to visit Tahoe for a day of diving in the face of inferior weather on the Monterey Bay (their original planned dive site).
This is a perfect example of how divers enjoying a dive can contribute to the Project Baseline: Tahoe effort. In a 60 minute dive, gathering the stats below took less than 5 minutes but the magnitude of this contribution is huge in terms of value to the study and understanding of Tahoe's nearshore water clarity.
Today NMDE divers Vanessa Belz and Martin McClellan ascended upon Patton Beach in Carnelian Bay on Lake Tahoe's north shore (39.22624,-120.07979) - also now known as Watermans Landing. In May of this year we established the benchmark in 37 ft directly in front of (north) the Patton Beach Fish - a 20 foot long, 8 foot high concrete fish that was discarded by the miniature golf course across the street prior to 2004 - when we first found it. Sometime between May of this year and 9 November, 2013, someone decided to remove the benchmark and line leading to the fish and place all the equipment in about 15ft of water and leave it there. At least they did not take it. This equipment was found by another local diver and returned to us.
Today, our goal is to reestablish the benchmark, and place additional line leading to the site. The reason for the line is that the bottom composition of Patton Beach is basically featureless and since the fish is approximately 1200 feet from shore, it is a tough navigation and we wanted to make visiting our Project Baseline: Tahoe [http://projectbaseline.org/projects/usa/lake-tahoe] site easier.
We scooted out on the surface to the approximate area and because the visibility was very good on this day, we were able to locate the fish very expeditiously as it sits in approximately 35 feet of water. We descended, re measured the location of the benchmark and placed the 8" diamater auger back into the bottom about 16 inches. This should hold. Interesting where the benchmark was placed was an obvious pit in the bottom about 18" deep and about 3 feet in diameter. Someone really had to work this out of the bottom so we hope that does not occur again. Once the benchmark was placed, we assessed the depth, 35ft per the gauge on the benchmark and 56 degrees F on the temp gauge (this compared to 31feet on my digital gauge and 52 degrees F) - the difference is the gauges on the benchmark are older, analog for the depth gauge and a simple outside thermometer for temp. After noting depth and temperature we assessed visibility which was at least 30feet but not 40feet. We can tell this as we have visibility markers placed every 10feet starting at 20 feet from the benchmark. If you can see the 3, which is 30 feet, which we could, and we could not see the 4, which is 40 feet, this gives us our visibility reading. Importantly this is the exact same for any diver visiting the site keeping the information collected for Project Baseline: Tahoe, scientifically valid. Finally, we took our photo of the fish and then began the process of laying line.
After attaching our line to the depth benchmark and providing a secondary tie-off, we headed 300 degrees to the nearest boat buoy. We then ran the line directly into the beach at about 340 degrees along the debris field of old boat buoy anchors which consist of old concrete beams, motor blocks, 55 gallon drums filled with concrete, etc. and lots of old boat parts. We made kind of a nice debris pile to debris pile type of course. Fun to dive and stuff to see.
Our dive was 83 minutes to a maximum depth of 35 feet with an average depth of 18 feet. We saw no invasive plants or animals but encountered a fish cleaning station, right at the Patton Beach Fish, where fishing operations from the Marina adjacent to this site stop to clean their clients fish. Thus, we saw lots of crayfish...bring a bag as we are certain that the local sportfishing companies know of this concrete fish.
