Wednesday, May 18, 2016

Low Water at Walden Pond

Posted by Richard B. Primack

“The Pond rises and falls, but whether regularly or not, and within what period, nobody knows, though, as usual, many pretend to know.”  -Thoreau, Walden

As Henry David Thoreau noted 160 years ago, Walden goes through multi-year cycles changing water level. This spring Walden Pond is exceptionally low, with a broad expanse of sandy margins around much of the pond, and contrasts with the pond’s recent high in the spring of 2010, when water entered the forest around the pond and even flooded the p
aths.

Low water at Walden this year means a large sandy margin all around the pond

The past few years of low water have allowed alder and birch saplings and wildflowers, such as lance-leaved violets and yellow wood sorrel, to establish on the sandy beaches below the forest margin. When the water rises again in coming years, this invading edge of plants will be drowned.

Lance-leaved violets have established along the beach

Young alder plants at the forest edge will likely drown in future years when the water rises again

The water has fallen so low this year that part of a submerged sand bar—one that Thoreau described in his survey of Walden Pond—is now exposed. In Thoreau’s 1846 survey, he noted that the sandbar across the mouth of what is now known as Thoreau’s Cove on the northwest corner of the pond (the cove closest to the site of Thoreau’s cabin) was 7 feet below the water’s surface.

Thoreau's Cove, a sandbar on the northwest corner of Walden Pond

Also related the low water level, the large vernal pool near Thoreau’s cabin site, known as Wyman’s Meadow, has no standing water. In typical years, the meadow fills with water in the late winter and spring, and mole salamanders, American toads, and other amphibians lay their egg masses in the water; later in early summer the pool is alive with tadpoles and juvenile amphibians. By the summer’s end, the pool dries out and the meadow becomes a carpet of colorful flowers. But this year, without any standing water, the amphibians have no place to breed—and children visiting Walden will have no tadpoles to catch.

Dr. Les Kaufman walks across Wyman's Meadow, which is uncharacteristically dry in 2016

The extreme low water and wide beaches that we are seeing this year—an extreme that Thoreau noted too—is a part of what makes Walden Pond so endlessly fascinating. Something to consider next time you take a stroll around the pond.

You can read my full article on this topic in the Concord Journal by clicking HERE.


No comments:

Post a Comment