What is a watershed?
A watershed is all of the land that catches rain or snow and drains into a common stream, river or lake.
Tellico Reservoir Watershed
The Tellico watershed begins at the mouth of the Little Tennessee River, approximately 25 miles Southwest of Knoxville, and end 33 miles South, at the outlet of the Chilhowee Dam.
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656 square miles.
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15,600 acres of water surface
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357 miles of shoreline
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120,000 acre-feet of stored water
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141 campsites
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1 day use area
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12 boat launching ramps
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2 major rivers
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49 creeks
The lake level can fluctuate between 807’ and 815’ above sea level. At normal summer pool elevation 813’, the reservoir holds about 100 billion gallons of water. During winter pool, that volume is down to about 60 billion gallons [The 40 billion gallons difference provides additional flood storage during the winter.] Each 1” change in lake level represents about 400 million gallons of water.
The water source is surface runoff and ground water seepage within the Little Tennessee River watershed. The area of Little Tellico River watershed is 2,627 square miles. If this area were to receive an even distribution of 1” of rain and it all were to run into the reservoir, that would be about 57 million gallons of water, or nearly the volume of the reservoir at winter pool.
During summertime, approximately ¾ of rainfall is absorbed into the landscape. During wintertime when vegetation is dormant, only ¼ is absorbed. What is not absorbed becomes runoff into the reservoir. According to TVA, over the course of an average year, 44% of rainfall becomes runoff.
Average annual rainfall for the Little Tennessee watershed is 51 inches, of which runoff is 22 inches. That is about 1.3 trillion gallons of water which will flow down the Little Tennessee River which equates to about 3.5 billion gallons per day. Disregarding topographical features of the reservoir and the irregularities in water flow patterns, this river flow would result in an arithmetic exchange of water on a monthly basis. The actual flow of the river varies considerably based on rainfall and many other factors taken into consideration by TVA River Operations management.
The reservoir is also a source of water for area residents. Up to 80 million gallons per day can be taken for treatment by the South Blount County Utility District and the Tellico Area Service Systems (TASS).
There are six permitted wastewater treatment facilities that discharge into the reservoir at a combined rate of about 4 million gallons/day. The purity of these discharges are closely monitored by TDEC, as well as by WATeR.