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Lake Turnover

11/14/2015

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                                                    “Lake Turnover”


We had a beautiful, warm, and dry fall along the shores of Lake Tarleton. The weather remained unseasonably warm into November. With Daylight Savings Time coming to an end, the days are getting shorter, and it has begun to feel a bit like winter. One would presume, based on the abundance of fog on the lake most mornings, that the lake temperature remains above 39 degrees. Why 39° so specifically, you may ask?


It turns out that the 39° mark is a significant threshold to the chemistry of water, a fortunate thing for the creatures that inhabit all fresh water lakes. 39°F is the temperature of maximum water density, a driving factor in “lake turnover”- that critical phenomenon on which aquatic plant and animal life are dependant. My hunch is that as the high temperatures drop, and temperatures plummet to sub-freezing temperatures overnight, our own Tarleton will soon experience its annual all-important fall flip. The turnover process usually happens twice a year- in spring and fall. The agitation re-oxygenates the lake. Oxygen is crucial for the survival of all manner of plants, fish, crustaceans, insects, and algae. Trout require particularly high levels of oxygen for survival, and Tarleton is famous for it’s large lake trout!


Here’s how the process occurs: due to absorption of the sun’s energy during spring and summer, temperature differences develop in the varying depths of a lake and the water tends to stratify into different layers. Swimmers feel hot and cold spots as they dive down a bit. The middle layer, known as the thermocline, acts as a barrier to any mixing with the deep layers. As a result, the deep layers become quite depleted of oxygen towards the end of summer.


Once summer turns to fall and temperatures begin to drop, the water reaches that magical threshold of 39 degrees and it is at its densest. This temperature is first reached near the surface where the water has contact with the air. This top layer then sinks to the bottom of the lake, where it displaces warmer water, which floats to the surface where it can also cool. Thanks to this phenomenon, the stratification built up over the course of the summer is erased. The water from the depths of the lake, which is low in oxygen and filled with decaying matter and sulfurous gases, is brought to the surface. Thereafter, storms and sustained wind overturn and mix the water in the lake, bringing fresh oxygen into the lake. There is often a unique odor, which can be detected during the “fall turnover.” Have you smelled this telltale sign of the turnover at Lake Tarleton yet this fall?


If water didn’t have the special chemical properties that it does, the process of the coldest water sinking to the bottom would continue until the entire lake was one solid block of ice, freezing from the bottom up. Obviously, this would spell doom for most or all of the lake’s natural inhabitants!


39°F is the temperature of water’s maximum density. Below this point, until it freezes at 32°, water actually expands and becomes less dense, allowing it to float above the warmer layer! This is the water that freezes and stays on the top, effectively capping the lake and sealing it off from further heat loss. The water beneath the surface of the ice does not dip below 39°, although the surface ice can become thicker, of course. The fish are likely thankful for this special characteristic of water!


Once a lake is frozen, the stratification of the lake begins anew in the frozen zones below the ice. During the winter, the lake creatures nearly deplete the oxygen way down in the depths. Fortunately, just as things get dire, spring arrives. When the ice melts and the water on the surface reaches that magical 39°, guess what happens? Yup, it sinks and infuses the deeper water with oxygen. The sinking water creates a convection current which churns the lake water, delivering a great dose of much needed oxygen. As the waters continue to warm, the lake begins once again to stratify, and the cycle continues. It’s not long after that that boaters, fisherman, and swimmers are back on the water, most of whom are blissfully ignorant of the dramas that have been playing out just beneath the surface of the water.












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A Historical Find 

2/27/2014

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Thanks to Mike DiPietro for this excellent find from 1977! What I find interesting is how this era finds the management plans for the Lake Tarleton region at an interesting crossroads. Not many years prior to this article, there were plans afoot to build 4,500 homes around Tarleton! By 1977, the scope of the plans had been downgraded to a mere condominium unit, a townhouse unit, single family dwellings, golf, tennis, and dining- making use of a scant 50% of the acreage. 

It's astounding to think about how drastically different our current shared experience of Lake Tarleton might be if any of these plans had come to fruition. Although not mentioned in this article, undoubtably many of the players who were to have a part in preserving the lake and the surrounding land were already in motion. And for that, we thank them! 
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The Old Charleston Road: The Unlabeled Dirt Road Yields Unique Experiences

10/4/2013

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In 1913, Henry Ford began using the assembly line to produce affordable automobiles.  This invention, combined with Eisenhower’s Highway Act of 1956, has transformed the face of the nation.  Sprawl, the term that denotes man’s ever increasing ability to travel long distances to get to work in the big city, spawns along major arteries into and out of cities and towns.  Coupled with the engrained American dream of land ownership and man’s universal need for contact with the soothing touch and sound of water, land on and around bodies of water are being gobbled up like Thanksgiving dinner.  The uninformed might conclude that pristine, remote locations have completely disappeared from the American landscape.  Part of me wants to perpetuate that myth to keep my personal sanctuary intact.  However, I now recognize that deceit is not required.  This land is part of the White Mountain National Forest, and will be protected (at least from developers) for eternity. And since there are no catchy fliers or brochures at New Hampshire rest areas acknowledging my hidden corner of the world, I feel as though I can rest assured that the masses will remain far away. Sadly though, the main reason why I have nothing to fear is that most Americans are lazy, and the concept of going someplace to walk around, explore, and “rough” it is totally undesirable.

If you see yourself as different from the common American, inertus ignoramus, and actually enjoy the thought of spending time out of doors, continue reading.

The Old Charleston Road won’t be found in any road map or atlas; nor will you find it listed under any hiking trail.  I’ve heard it receives a decent amount of snowmobile traffic in the winter, so maybe it’s labeled in a snowmobile guidebook.  On topographical maps it’s labeled “Jeep Trail.”  But to the initiated it’s known as the Old Charleston Road.  The name derives from the small farming community that clawed out an existence just northeast of Lake Tarleton in the early 1800’s.  The few farming families were able to overcome the harsh winters, rocky soil, and hilly terrain to make ends meet.  Their true demise was their isolation; in particular their distance from the nearest railroad station.  Their inability to get crops to the tracks in a timely and cost efficient manner meant they couldn’t compete with the larger farms from more hospitable regions.  Now all that remains of Charleston are the stone walls that mark property lines, a couple apple orchards, a couple cellars, and one graveyard.  In a story that runs counter to the trends in America (though parallel to New Hampshire trends) the forests have won back the land.

The Old Charleston Road is a dirt road that loops around the eastern side of Lake Tarleton (the largest lake in the White Mountains), though too deep inland to get a glimpse of the lake.  Although the entire circuit can be hiked, it is not advised (part of the trail runs under huge power lines while other parts can be confusing).  Most of the points of interest are on the northwest side.  Start on the western side, where the Eastman Brook passes underneath 25C- look for the E-2 sign. 

Although the Old Charleston Road is a charming walk in the woods, it in and of itself does not provide surreal experiences. Those, however, can be found with relative ease on “side trails.”  I delineate “side trails” because these paths have not been officially maintained since the days of the Lake Tarleton Club.  I love the fact that the trails are unkempt (don’t get me wrong- I also love well-manicured trails with identifiable and consistent trail markers and a nice sign with mileage at the trailhead). Forays off the beaten track provide totally unique experiences.  Gone are the safeguards we’ve grown accustomed to- you are now in unchartered waters.  And although you’re confident that many people, probably hundreds, have done the very same hike, you’re mind intuitively asks, “But how long ago did the last hiker traipse along this path?”  Oftentimes you are uncertain where your meanderings might take you; this breeds a dichotomy of emotions- surface level anxiety, and deep seeded pleasure as your innate desires to be a frontiersman and explorer are finally realized.  

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    Rob Wipfler

    Lake Tarleton Association President 

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