Hidden Underwater Hotspots

Invisible to the eye and depthfinders, underwater springs are magnets that attract bass year-round.

What Are Underwater Springs?
Geologists will tell you that a vast quantity of water lies beneath the Earth's surface. One scientist estimated that more water underground exists in Florida than in all of the Great Lakes combined.
A spring occurs when water escapes from beneath the planet's crust. Perhaps you've hiked in a hilly area and noticed water trickling from the face of a rock bluff — that's a spring. But spring water can also escape from a crack or fissure on the bottom of a lake or river. And where it does, it can spell unusually good bass fishing.
Springs occur almost everywhere: most commonly in high terrain, less frequently in desert regions. Chances are the area around your home, including the bottom of your favorite bass lake, has several flowing springs.
Why Springs Attract Bass: In the popular mindset, nothing is purer than spring water. In fact, it's the beverage of choice of many Americans who prefer Evian or Perrier over iced tea or sodas.
One reason why spring water can be exceptionally pure is the natural filtration it undergoes as it flows through rock and sand toward the Earth's surface. Obviously, in a lake or river with poor water quality, bass can thrive around a pure, flowing spring. But spring water has characteristics other than purity that make it important to the bass angler: 
• Spring water usually flows at a constant temperature, regardless of the season. This is why a spring, emerging from the bottom of the lake, can produce excellent bass fishing, especially in midwinter and midsummer. Recall the example cited at the beginning of this article. The temperature of the main lake was 41 degrees, but the temperature around the underground spring was 18 degrees warmer. The bass, being a cold-blooded creature, is active in direct proportion to the temperature of the water in which it swims. In frigid weather, bass will seek the warmest possible water, which is often close to a flowing spring. Conversely, in the heat of summer, although the lake water may rise to 90 degrees, the area around the spring will be much cooler and attract active bass. The temperature of a spring depends on many factors-hot springs are found in some areas, but the majority run between 62 and 73 degrees, a prime temperature range for active bass.
• Underwater springs moderate the lake or river temperature. One little-known fact about big bass is that they are more common in regions that do not undergo dramatic seasonal shifts in temperature. This is one reason why more lunkers are caught from lakes in California and Georgia than from waters in Minnesota or Illinois. As spring water emerges from the lake bottom, it mixes with the surrounding water to either raise or lower its temperature, keeping the area around the spring at a fairly constant temperature year-round. "Bass Professor" Doug Hannon, the famous Florida big-bass expert, has caught bass over 16 pounds from spring-fed lakes and rivers. As he explained, "These waters vary relatively little in temperature from one season to the next, creating a near-perfect environment for bass."
• Spring water is often low in oxygen. Because its source is deep underground, spring water has no contact with the atmosphere, and therefore has a low oxygen content. Bass, of course, need oxygen in the water to survive. Fortunately for the fisherman, areas close to springs often exhibit lush aquatic weed growth (because of the favorable water temperature), and weeds are great producers of oxygen.
How To Locate Springs: Submerged islands, drop-offs, flats and channels are all easy to find with the aid of a depthfinder and topographic map. Not so with underground springs. They're seldom marked on maps and not easily located with a depthfinder. Here are clues to help narrow your search.
The largest springs may boil out of the ground and create turbulence underwater or on the surface. Silver Springs in Florida is a classic example - visitors to this spectacular attraction can look down into the crystalline water and actually see the spring gushing forth. Smaller springs are the norm, however. These often seep rather than gush, making them difficult for even a diver to spot. Here's a hint: Scan the lake and look for areas with a fine mist hanging over the surface in summer, or a telltale slick spot on the surface in winter. The dramatic water temperature difference that a spring creates is the cause. Another way to locate springs in winter is to watch for lush weed growth on the bottom in clear water - a good tip-off of a nearby spring. Also, watch for rocky banks that have water seeping from them. This moisture is a tip-off that an underground spring is running behind the rocky face and beneath the lake's surface. A water temperature meter is always useful when bass fishing, and imperative if you're hunting for springs. Keep it on while cruising the lake; if the temperature rises or falls significantly in a specific area, you've probably located a spring.
Breaking The Rules: When fishing around a spring, it pays to break some of modern bass fishing's most ironclad rules.
Rule 1 says you must use a slow retrieve in winter. But remember, the presence of an underwater spring may have a dramatic warming effect on the lake water. I have far better luck using a fast retrieve with lures like shallow-diving minnow lures and lipless crankbaits than by slow-crawling jigs or plastic worms. Warm spring water rises toward the lake's surface; hence bass will seldom be on the bottom around a spring. If the area close to the spring shows a water temperature of 60 degrees while the rest of the lake is 49 degrees, expect bass there to be active, not sluggish.
Rule 2 says you should stand up while casting for bass. But in the super-clear water around most emerging springs, standing to cast makes you highly visible to bass. Remain seated, and keep your rod tip low to the water to further reduce your visibility.
Rule 3 says topwater lures are for late spring through early fall. You may feel foolish casting a buzzbait or surface popper in the dead of winter, but if you're fishing around a spring, these baits can produce. Warm water draws baitfish in droves, and active bass commonly attack baitfish by driv-ing them to the surface.
Rule 4 says you should thoroughly saturate an area where you know bass are lurking, But because spring water is often exceedingly clear, it won't take bass long to realize that a predator (namely you) is in their midst. Once you've located the spring, work quickly with fast-moving baits. Avoid running your boat over the area more than absolutely necessary, and turn off your depthfinder. Time and again I've seen bass in high-visibility conditions develop lockjaw when they feel the pulse of an LCR.
Choose The Right Lure For Underwater Springs: The temperature of spring water (warmer than lake water in winter, cooler in summer) usually means active bass. But the unusual nature of springs should influence your lure selection.
• Extremely clear water around springs; demands realistic lures. Long, slender minnow imitators offer a realistic representation of living bass forage in clear water.
• As spring water is spread into the lake, its influence diminishes. In winter, the closer to the source of the spring you're fishing, the clearer/warmer the water is likely to be. As you move farther from the source of the spring, use slower-moving, deeper-running and more visible lures. You should be using a clear or bone topwater or shallow-running minnow imitator near the source of the spring, a spinnerbait fished in the mid-depth zone where the water is stained, and a bottom-bumping jig or plastic worm farther from the spring, where the water becomes murky. As you move away from the spring and the water becomes murkier, your lure colors should shift to darker and/or fluorescent hues.
Break New Ground: Chances are all the obvious structures on your local lakes - the points, the weed lines, the dropoffs - have been hammered to death by other bass anglers. The challenge to today's serious bass angler is to find places that haven't been exploited by your competition. Underwater springs are bass magnets that have escaped the attention of the masses. When you find them, you may tap into some of the most sensational fishing of your bassin' career.