NMDE/Project Baseline: Tahoe, 30 August 2015 – Sand Harbor – Station Evaluation

Today, NMDE members Martin M. and Vanessa B. headed out to Sand Harbor to “get wet”, check out our Project Baseline: Lake Tahoe dive station – soon to be upgraded and sponsored by the Tahoe Truckee Community Foundation – and then head out to the inner wall about 1000′ off the beach.

Our first stop for the dive was at our PBLT Station.  We set this up in 2012 and have had a variety of entries since its inception.  When we set the station, the depth was at 26 feet; today? 19 feet.  The image below is Vanessa checking the reading…

The depth/temp board as you can see is difficult to read but we just received a grant from the Tahoe Truckee Community Foundation that will allow us to upgrade this station with a top down depth/temp board – To be installed in September.  The new design will allow a diver to float directly over the top of the gauges and take their reading.

Taking a reading for PBLT only takes about 60 seconds.  A diver looks at the depth gauge and temperature gauge on our depth benchmark, notates that.  Then looks off to the west noting the visibility markers…

Martin placing a typical “visibility” marker – this is 30 feet from the benchmark.

Once a dive team has this data, then they can email it to us nmde(at)att.net.  If they have photo/video capability, we want them to take a photo of the boulder to the left of the station and the dive team can also include that image in the email.  When we receive that email,  we then take that data and image and put it on our Global database; projectbaseline.org

Once we completed our data notations and photos, we continued out along a bearing of about 220 staying right next to the boulders to our left.  We noticed thick clumpy green bottom algal growth, not attached to rocks but floating in patches on the sandy bottom – never before noticed to be this dominant a bottom feature during a dive.  The thickest concentration was between 18 feet and the30 feet with an obvious reduction in dominance above and below this depth range.  The algae (?) completely dissapated at about 31 feet.

Metaphyton Algae build up right next to the “barge”  – 18 feet depth.

Our dive was 95 minutes to a max depth of 70 feet.  The lake state was choppy with 1 foot waves due to winds the previous day continuing into our dive.

Today’s PBLT Stats:

• Depth – 19
• Temp – 66
• Vis – 60 feet

The green clumpy metaphyton algae resting on sandy bottom – for scale – a 4 inch double ender was placed on bottom. This algae is a combination of crusty blue-green algae and green filamentous algae maybe even some Spyrogyra

Attached periphyton algae on the granite boulders.  30 feet of depth; now dying off late in the growing season.