Photo by Michael Skinner

Tennessee Valley Authority reservoirs are sprawling lakes with long, thin fingers and slow currents. In other words, excellent catfish territory. Deep water, rocky cover and muddy flats with a forage base of shad and panfish provide the perfect environment for cats that sometimes break the 50-pound mark.

A couple of factors come into play on Tennessee's reservoirs that will make for more productive days on the water, said John Riddle, a Region II fisheries biologist.

"Anglers forget that the upper ends of reservoirs have more nutrients flowing into them through their tributaries and the main stream than the lower ends do. The nutrients are needed for the microscopic plant life that is the basis of the food chain. By the time the water washes into the lower end of the reservoirs, the nutrients are lost and the water is less fertile. What that means is that there will be higher concentrations of fish in the upper ends where the food chain is more abundant.

"We have years when the water is high and the nutrients are washed into the lower ends, but this changes from year to year. During dry years, the nutrients stay in the upper ends of the lakes and the difference between the beginning of the reservoirs and the lower sections is more pronounced."

Another factor affecting anglers is the thermocline, Riddle said.

"By July, we have a thermocline on all of our reservoirs. In a fairly clear lake, you don't want to be fishing too shallow, but you don't want to go below the thermocline either. You should be looking for catfish in about 6 to 15 feet of water."

And many anglers make mistakes when it comes to fishing a lake where a thermocline has set up, Riddle said.

The line in the water column that divides the upper layer of warmer, well-oxygenated water from the colder, oxygen-depleted water is called the thermocline. Many of us are familiar with the word but pretty much ignore it after that.

In waters where a thermocline forms, the catfish will be found above it. Fishing below the thermocline will mean fishless days.

The problem is that locating the thermocline isn't easy.

It's said that divers can feel the drop of several degrees in water temperature once they drop below the thermocline. Locating this line between productive water and the lifeless depths below isn't nearly as easy for those of us who are still up there in the boat.

Riddle pointed out that there is no cheap way to determine how deep the thermocline is.

"All you can do is use your fish-finder to locate how deep the fish are holding. Fish will stack up just above the thermocline and you can usually judge how deep to be fishing."

Fish too deeply and you'll just be beating fishless water.

With all of that being said, here are waters where urban anglers can tangle with loads of catfish and have the chance at a trophy, all within driving distance of home.

TIMS FORD
"Tims Ford has plenty of channel catfish, some blues and a fair population of flatheads," said Riddle, who manages the lake for the TWRA. "Channels in the 16- to 18-inch range are fairly common, with some bigger ones available. We sample channels in TWRA fish surveys and usually get a pretty broad range of sizes in Tims, just as we do in all of our reservoirs.