There are 7 major lakes surrounding Knoxville. These are Cherokee, Douglas, Fort Loudoun, Melton Hill, Norris, Tellico and Watts Bar Lakes.
Norris, Douglas and Cherokee Lakes are reservoir lakes. The water level varies the most on these lakes. Fort Loudoun, Watts Bar, Tellico and Melton Hill only vary 4 to 7 feet. All of the lakes are lowered in the winter months, generally from mid-November to mid-April. Most folks feel it's too cold to go out on the lake in those months. Personally, I feel year round view is important, not year round water. (It really is too cold on the water!) But that is just my opinion.
Fort Loudoun and Watts Bar Lakes are part of the Tennessee River. This river eventually connects to the Mississippi River. Tellico Lake connects to Fort Loudoun. Melton Hill Lake connects to Watts Bar. Because of the long range navigation options, these four lakes experience the widest variety of boats from small bass and jon boats to luxury yachts, houseboats and barges.
Below is basic information I have gathered from the TVA website. The site has much more information including charts with daily water level reports, fishing information, recreation information, etc. so you may want to browse a bit there.
Norris Lake:
Norris provides 809 miles of shoreline and 33,840 acres of water surface. It is the largest reservoir on a tributary of the Tennessee River. The recreational use of Norris Reservoir exceeds that of any other tributary reservoir in the TVA river system. Norris Dam is 265 feet high and stretches 1,860 feet across the Clinch River. The town of Norris, built to house workers on the dam, was a planned community that became a model for others throughout the nation. It was sold to private owners in 1948. The water level in Norris Reservoir varies about 23 feet in a normal year.
Douglas Lake:
Douglas provides 513 miles of shoreline and about 28,420 acres of water surface for recreation activities. The water used to generate power at Douglas is used again and again at the nine TVA hydroelectric plants located along the Tennessee River from Knoxville to Paducah, Kentucky. Douglas Dam is 202 feet high and stretches 1,705 feet across the French Broad River. The water level in Douglas Reservoir varies about 41 feet in a normal year.
Cherokee Lake:
Cherokee Reservoir provides nearly 400 miles of winding shoreline and about 28,780 acres of water surface. Cherokee Reservoir is named for the tribe of Native Americans who once inhabited the area. The great Indian warpath, once followed by Daniel Boone, crossed the basin now filled by the reservoir. The dam is 175 feet high and stretches over a mile—6,760 feet—from one end to the other. The water level in the reservoir varies about 27 feet in a normal year.
Fort Loudoun Lake:
Fort Loudoun provides 379 miles of shoreline and 14,600 acres of water surface. Fort Loudoun is named for the 18th century British fort built on a nearby site during the French and Indian War. The fort was named for John Campbell, the fourth Earl of Loudoun, commander of British forces in North America at the time. Fort Loudoun Dam is 122 feet high and stretches 4,190 feet across the Tennessee River. The 60- by 360-foot Fort Loudoun lock raises and lowers river craft about 70 feet between the reservoir and Watts Bar Reservoir.
Watts Bar Lake:
Watts Bar provides 722 miles of shoreline and over 39,090 acres of water surface. In addition to forming a navigable 72.4-mile-long reservoir on the Tennessee River, Watts Bar also creates a slack-water channel for navigation more than 20 miles up the Clinch River and 12 miles up its tributary, the Emory. Watts Bar Dam is 112 feet high and stretches 2,960 feet across the Tennessee River. Watts Bar has one 60- by 360-foot lock that lifts and lowers barges as much as 70 feet from one reservoir to the next.
Tellico Lake:
Tellico has 357 miles of shoreline and 15,560 acres of water surface for recreation activities. Tellico Dam is 129 feet high and reaches 3,238 feet across the Little Tennessee River. Tellico Reservoir stretches 33 miles along the Little Tennessee River into the mountains of east Tennessee. Tellico has a flood-storage capacity of 120,000 acre-feet. Water from Tellico helps drive the four generating units at Fort Loudoun Dam.
Melton Hill Lake:
The reservoir provides nearly 193 miles of shoreline and 5,470 acres of water surface for recreation. Melton Hill is the only TVA dam on a tributary stream with a navigation lock. The dam is 103 feet high and stretches 1,020 feet across the Clinch River. The navigation lock at Melton Hill has a 75- by 400-foot chamber and a maximum lift of 60 feet.