Reservoirs are manmade impoundments of free-flowing rivers, flooding and altering the habitat and character of the original system. Deep sections typically feature little current, appearing more like lakes. Inlet portions typically experience greater flow and function a bit more like rivers, or at least river-lake hybrids. Walleyes running upriver to spawn react like river fish. Those same fish using main-lake areas later in the year function more like lake dwellers, for a while anyway, until they migrate again, triggered by seasonal urges, rising or falling water, forage movement, or some other mysterious combination of factors.

In most cases, walleyes in reservoirs are movers, far more than most fish in natural lakes, unless the lakes are huge. Fish seasonally migrate long distances, first to suitable spawning areas, and later following and feeding on suspended baitfish like ciscoes, smelt, or shad. Conditions change daily, even hourly, as the wind shifts or builds. Today’s hot fishing spot may resemble the dead sea for the next week before suddenly exploding again in frenzied activity. Fish can be caught in deep water one day, shallow the next, and suspended the day after. Or on all three patterns within a few hours. Or not at all.

Don’t be dissuaded. The changeable nature of reservoir walleye fishing is at once both its greatest challenge and its largest reward. Some of the finest walleye fisheries in America are big reservoirs, and some of those offer mighty big fish. Lakes constructed where no lake stood before bring fishing opportunities to anglers across North America. And with walleyes today stocked in a wide variety of reservoir habitats, learning to recognize and adapt to the ever-changing environments of reservoirs brings great rewards and potential trophies, particularly outside the traditional walleye range.

Plateau—The plateau impoundments of the North and Central Plains are the undisputed kings of reservoir walleye fisheries, producing both numbers and size of fish. These are waters where you can pull up on a point and catch a bunch of walleyes, rather than singles. They’re deep, clear, expansive waters, miles wide and many miles long, that at times are swept by fierce prairie winds.

On large plateau reservoirs, walleyes typically run long distances up major rivers to spawn on rock and gravel swept by current. On small impoundments lacking rocky feeder rivers, the fish spawn along the rock face of riprap at the dam or causeways. Almost immediately, they begin moving back toward midlake, following developing forage opportunities. Shad, smelt, ciscoes, and suspended forage often key the big-fish bite, though perch and minnows at times provide backup munchables.

Long points extending into deep water intercept fish movement; and in calm conditions, livebait rigging or jigging, as deep as 20 to 40 feet, excels. When the wind blows, wave-generated shale mudlines form, and walleyes rush up shallow, into as little as 2 to 5 feet of water, to pounce on hapless, disoriented prey. Pitch cranks or jigs to the shoreline. In average conditions, use spinners-bottom bouncers-crawlers to quickly cover water, checking point after point, predominantly on the windy side of the lake, to locate active biters.

Fluctuating water levels from year to year form wave-pounded breaklines along shore; old breaklines from low-water years, now flooded, often key fish activity at uniform depths around the lake. Fluctuating water often prevents the development of much rooted weedgrowth, although high water floods terrestrial grass and standing timber, providing a shallow cover option for gamefish and baitfish.

Lowland or Wetland (Flowages)—Most anglers consider flowages to be natural lakes, though in reality they’re shallow reservoirs constructed in woodland or lowland terrain inundating substantial areas of marsh and standing timber. Most flowages date back to the early 1900s.

Flowages generally have dark water, created by run-off from surrounding tannic swamps. Siltation’s a major factor, often inundating any semblance of the old river channel other than in the lower reaches near the dam. Flowages are fed by rivers ranging from small to substantial, and they often host an upstream walleye spawning run in spring, similar to walleye movements in other impoundments. Otherwise, fish spawn on scattered main-lake rock points or reefs, or along the rock riprap faces of dams or causeways. Or the fishery may be sustained by stocking, though most offer self-sustaining populations of smaller walleyes, with the occasional scattering of larger ‘eyes.

Most North Country flowages originally contained abundant flooded timber, stump flats, fallen trees, and other assorted wood cover. Due to the age of most flowages, however, much of the original wood, other than newly fallen shoreline cover, has eroded away to remnants. Still a substantial form of cover, wood today often shares the limelight with shallow weeds—cabbage, coontail, reeds, and cane—that generally grow in shallow bays, often limited to depths of 4 feet or less by a low level of sunlight penetration in the dark water. Even so, as water clarity marginally improves as flooded wood cover decomposes, new cabbage patches develop on shallow midlake humps, forming a new vista for flowage walleyes.

Cover, more so than depth, is key for flowage walleyes much of the year. The edges of weedbeds or floating bogs are fished with slipbobbers and leeches. Anchor and cast similar presentations to the tops of shallow humps with weed, wood, or rock cover, often finding fish in less than 8 feet of water. Where substantial amounts of standing timber remain, weedless jigs tipped with leeches or crawlers are flipped to individual trees, letting the jig fall to penetrate the root system at the base. Short, precise tactics tend to outproduce long casts.

If such cover adjoins any form of river channel, so much the better. By midsummer, trolling crankbaits along the deep 10- to 15-foot edges of timber adjoining midlake channels may outproduce presentations in shallower cover. In fall, walleyes tend to move deeper, dropping into channel bends or intersections in the 15- to 25-foot range, depending on available depths. Vertical jigging or livebait rigging excels at this time.

Flatland—Flatland impoundments built in farm country and forest lands are sometimes called flowages, though they differ from lowland flowages built in swampy terrain. Flatland impoundments typically feature large, middepth flats of perhaps 6 to 15 feet in depth, dropping quickly into distinctive river and creek channels winding through the lake. A sandy bottom is prevalent in many areas. Walleyes may spawn either on upriver rock shoals or along riprap, depending on what’s available.

Fish use shallow shoreline cover to a degree, primarily in spring, but not as much as in lowland impoundments. As the water warms in summer, walleyes typically move out deeper, following timber edges or channels, where they relate to twists and turns of the channel edge, generally adjacent to flooded timber. The fish may not drop deep; 10 to 20 feet is common. They tend to be up on the lip of the channel edge, perhaps extending up onto the timbered flat. Trolling cranks or spinners-bouncers-crawlers is great for checking the breakline. In the timber, which often is scattered remnants, mostly lying down rather than vertical, cast crankbaits or weedless jigs.

In fall, walleyes tend to drop deep into the channels, particularly if fall drawdowns occur. Now, 20 to 30 feet is common. Channel bends and intersections concentrate fish. Vertically jig or rig with livebait. Scattered sticks and snags may rob a few rigs, but by and large, channel basins are relatively snag-free, except where current washes in random wood. Such lakes in the Midsouth often host excellent sauger fisheries.

Highland—Never a numbers game, even in the best of fisheries, these deep, clear, mountainous lakes of the Midsouth nevertheless offer a chance for huge walleyes. Most of the 20-pounders ever caught have been taken here, and the possibility for a new world record still exists.

Highland walleyes run up feeder rivers to spawn. Finding rock is never a problem; shoals and pools abound. Huge fish are caught at night in February and March by casting or longline trolling large diving crankbaits.

After spawning, walleyes quickly disperse back into the deep clear lake, where the location mystery deepens. Some fish suspend, at times, feeding on shad. Daily cycles of power generation through huge dams set up a subtle current that often triggers a short burst of feeding activity along prominent deep points.

Most fish are caught during low-light periods or at night on prominent points or humps adjoining a deep 60-foot-plus river channel. Look for schools of suspended baitfish near structure, possibly with big fish below. Jigging spoons, bottom bouncers-spinners-crawlers, livebait rigs, and crankbaits produce at the 15- to 40-foot levels, above the thermocline. Early summer probably provides the best opportunity for the most fish.

But highland walleyes are phantoms; catch one or two, and the rest quickly spook and disperse off the point. You won’t catch a limit in one spot. Due to extremely clear water and hot daytime temperatures, most walleyes are caught at night.

Tracking studies reveal that standing timber often holds big walleyes during the day, and that the fish move out of cover to feed on shad at night. Walleye anglers often won’t fish timber because they lose rigs to snags. Switch to cranks, and give it a try.

Hill-land—Probably the closest parallel to moderately fertile natural walleye lakes, hill-land impoundments offer a structural wealth of fishing opportunities—humps, flats, channels, timber, moderately deep water. They also offer better numbers of fish than highland impoundments, though not the exceptional size. Still, the fish are bigger than in most flowages, though the numbers aren’t as large. This is a real middle-of-the-road environment.

Strangely enough, not many good hill-land walleye impoundments exist; most reservoirs constructed in such terrain tend to be bass fisheries, some with walleyes present. Walleyes likely will spawn on rock shoals in a feeder river, then move back into the main lake. They feed, they roam, they use typical structures like points and humps adjoining the river channel. Early summer suggests bottom bouncer presentations. In fall, jig the tips of points meeting the deep river channel with jigging spoons or jig-and-minnow combos.

Canyon—Exceptionally deep reservoirs of the American Southwest sometimes host walleyes that feed on shad. Some host numbers and even size, walleyewise, but most are only fair. Towering cliffs and winding canyons typify the setting.

Fish spawn on rock toward the back ends of major feeder creeks. Then they move miles back toward the main lake. Prominent structure is rare in such a steep, deep environment where canyon walls often plummet vertically to several hundred feet. If you find a sloping shoreline, fish it with bouncers, jigs, or spoons. An extended point or hump is a bonus. Fish it hard, because walleyes will use it.

More likely, structure will be subtle, formed by sections of cliff breaking off the wall and sending a rockslide plummeting into the depths. Note areas where cliffs appear to be broken, move up tight to the wall, and lower a spoon or jig 50 feet or more. In fall, walleyes may be as deep as 100 feet in the crystal clear water.

Wind whistles through miles of expansive canyons, though mudlines are rare due to the rocky, rather than soft shale terrain. As on plateau impoundments, however, exercise caution as a boater. These two reservoir types are subject to sudden wind, big waves, and long runs between boat accesses.

Tips For Fishing Big Reservoirs

Scott Fairbairn, former biologist and past PWT Angler of the Year, relies on a basic philosophy for fishing big reservoirs in spring. In lakes like Oahe in South Dakota, where a natural spawning area is available in the lake itself, walleyes don’t have to run to the rocky face of the dam to spawn.

“Most of the major creek arms in Lake Oahe probably have at least a small population of walleyes that spawn, forage, or both in spring,” Fairbairn says. “Some more than others. The Cheyenne River arm, for example, is a major spawning area, with other lesser creeks branching off the Cheyenne holding at least temporary populations of walleyes.

“In spring, water within creek arms warms quicker than in the deep main lake, and fish of all species are attracted to the warming environment. In addition, water levels usually are stable or rising over about a two-month period, which further draws walleyes and baitfish up into creek arms.

“I’m usually looking back into at least the midsections, if not the back ends of creek arms, for spawning-related sites, specifically, rock or gravel bottom. Sometimes, rocky areas are extensive and obvious. Other times, they can be surprisingly subtle, like long sections of mud banks with occasional patches of small broken rock vein extending down into the water. Walleyes key on those areas, partially for spawning purposes, and partly because they also attract forage. In many cases, small specific spots hold walleyes.

“With water levels currently low on the Missouri River system and many other reservoirs throughout the West, people should be out photographing shorelines to document the locations of prime spots before they flood again once the water begins to rise. They’re prime fish-attracting areas for the future.

“Because these are sometimes small spots, using presentations that keep you right there, focused on limited areas, generally are best in spring. Sure, you often need to troll larger areas to determine smaller sections that hold fish. But once you locate areas of fish activity, turn around and focus on the key spot. I learned to keep bait in the strike zone at Mobridge some years ago, where catching a walleye and then trolling on down the shoreline was a mistake, because you left the fish. Instead, you had to slow down and refish prime stretches.

“Jigs, livebait rigs, even slipbobbers typically are your best tactics in spring. Don’t forget your anchor, either. The fish generally are shallow, right up onto the banks, usually in less than 10 feet of water. Presentations that strain the 5- to 8-foot depths are best.”

If spring fishing revolves around plying precise areas with shallow presentations, summer is more geared to covering water with presentations that effectively search for schools of walleyes actively roaming the impoundment in search of food. Rick Olson, past PWT Angler of the Year, fishes reservoirs throughout the plains, mountain, and midwestern states, and he knows that in order to catch walleyes, the first thing you need to do is find active fish.

“Reservoir walleyes tend to be migratory,” Olson says, “and schools are commonly here today, gone tomorrow. A great spot one day often is totally dead the next; the fish simply aren’t there. They’re off to greener pastures, so to speak, where food is easily available.

“Wind plays a big part in locating big-reservoir walleyes in summer, with the windy side of the lake tending to be best. It’s not that all the fish suddenly run to the windy side of the lake; it’s just that the fish there tend to become more active and catchable as the onset of wind begins tearing up the shoreline, creating mudlines that reduce visibility and make baitfish more vulnerable to predation by walleyes.

“Because wind draws active walleyes shallow, you usually can troll through such areas relatively quickly to determine if active fish are present. Bottom bouncer-spinner combos dressed with nightcrawlers are superb for such conditions. So are shallow-running crankbaits. They let you cover and eliminate long sections of shorelines until you suddenly run up on biting fish. At that point, you often can simply turn back around and retroll through them to catch more fish. You also have the option to switch to more precise casting tactics with jigs or crankbaits, if fish seem more tightly concentrated along a distinct feature like an inside turn, rather than strung out along a general stretch of shoreline. It’s a judgment call based on what the fish are doing.

“In the absence of wind, however, the walleyes tend to be deeper, lying along the tips of major shoreline points that extend into the reservoir and intercept passing schools of walleyes and baitfish. Or, they can be suspended outside the structure. Often your best bet is to simply run a series of points relatively quickly, using electronics to first determine the presence, depth, and orientation of the fish to structure. And believe me, on a giant reservoir, you can spend a lot of time looking for fish life before ever putting a bait in the water. Once located, select a likely presentation, like livebait rigging with big chubs for fish holding tight to a breakline, or trolling crankbaits with leadcore line for fish suspended off the sides of structures.”

Best advice: play the wind, if available, and don’t get stuck on any one area, type of spot, or method. To consistently catch walleyes on big reservoirs in summer, you need to be mobile and versatile, and match your tactics to the current conditions, which commonly can and do change throughout the day.

Unnatural Walleyes

Though reservoirs are artificially created environments, they share many aspects of walleye location and behavior with lakes and rivers. As water levels rise, walleyes tend to move shallow, sometimes penetrating cover. As levels recede, fish tend to abandon shallow cover, moving more toward the main lake. Prominent points and humps always are candidates to check, particularly where they adjoin deep water. In larger, deeper impoundments, deep water may occur almost everywhere. In smaller, shallower reservoirs, submerged river and creek channels may provide the only available deep water. Deep is also relative; it might be hundreds of feet, or 15 to 20. It all depends on where the reservoir is located, because all reservoirs begin as rivers, then adopt the landform on which they’re built. When walleyes adopt them as home, they react and behave accordingly.