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Monday, March 07, 2011

Two Watersheds

Two Windham County watersheds divide on the ridge line of my house. Today, icicles drip from the eaves on the north and south sides. The droplets hit the ground and join other melt waters running down through the woods on terrain that tilts either toward the West River to the northeast, or Stickney Brook to the south.

The river valley is wide compared to the narrow ravine that Stickney Brook passes through on its journey from Sunset Lake in the high country of Marlboro town. But even the most generous expanses of bottom land along the banks of the West River are mere scraps compared to the alluvial plains bordering the Great River, the Connecticut, downstream of where the two meet at Brattleboro. The West, in its entirety, is a Green Mountain State creation. It’s the first major tributary of the Connecticut River to make both its head-water and confluence within Vermont’s borders.
       
The maple sugar trees I tap at this time of the year grow among the ledges on the slopes around my home. I hang 260 metal buckets to catch the clear, sweet maple sap that is boiled and reduced until it becomes syrup. Through the bare, top branches of the maple trees I can see the distinctive profile of Black Mountain, just across the West River.          

Unlike most hilltops in Windham County which have mantles of deciduous trees, Black Mountain is cloaked in evergreen. The dark pine forest of its upper reaches is the biological result of the mountain’s unique geologic standing. It’s the only “pluton” of pure granite to be found here. Pitch pines are able to survive and thrive on Black Mountain’s bare rock dome. When the first settlers spied the knob from a distance, it stood out from its lighter colored neighbors. It looked “black”, and hence its name.

Tens of thousands of years ago, my land would have bordered the shores of a beautifully iridescent lake.  It would have glowed because the fine particles suspended in it’s waters would have absorbed all but the blue wavelengths of sunlight, and by that optical slight-of-hand have created the brilliant opalescent color that is characteristic of all glacial lakes. These days, I must be content to get a glimpse through the trees of a flash of sunlight reflecting off the river’s current, at an elevation hundreds of feet lower than that of the long-lost lake’s surface.
       
The silt and sand of the former lake bed, laid down in seasonal cycles, remains to this day. The warmth of summer suns melted the top of the retreating glacier and shrunk its margins. The melt accumulated into raging cataracts that roiled the lake waters. As a result, the summer’s deposits contained coarse materials. With the advance of winter the torrents slowed to a trickle and the lake surface froze. From the quiet waters under the ice, fine particles filtered out, coating the lake bed with a thin layer of clay. Year after year sand and clay settled in clearly defined bands. In 1920, a Swedish geologist went into a local gravel pit and counted the layers, or varves, of our lake bed. He determined that the lake was a fixture in this valley for 4,000 years.

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