Rivers are different every day. Holes move. Water levels fluctuate. Clarity worsens with every rainfall and improves with every dry spell. Weeds grow well one year and seem nonexistent the next. It gets complicated, to say nothing of the fact that the water is moving across the landscape, creating an irresistible force that easily can demolish a carelessly captained craft.

Rivers are intimidating, which is why river rats are such happy people. Less pressure. And when river rats find fish, they find aggressive, biting fish. Consider walleyes in rivers. Flowing water quickly carries wounded and otherwise easy targets out of reach. Walleyes in rivers have only seconds to decide to bite or not to bite.

But all that intimidating stuff? Start slow and simple. Constantly scan the surface for snags or boils indicating shallow rocks. Use a flasher for quicker response time. For safety, have life vests, an anchor, and a sharp knife ready at all times. And remember that three observable factors affect the location and aggressiveness of river fish of all species: water depth, water clarity, and water temperature. Here’s a thumbnail guide to help you locate walleyes faster in flowing water from late winter through summer.

(1) River fish follow the path of least resistance when migrating. Walleyes migrate upriver in autumn to winter, stage, and eventually spawn in spring. During prespawn, they migrate from wintering holes to spawning areas in water temperatures from 34°F to 40°F. When walleyes move farthest during these migrations, they move at night, using darkness to cover them through the shallowest flats. When moving against current, they slide from current break to current break and swim upstream along the inside turn of riverbends, where current is greatly reduced. Distance also is reduced by following the inside bend.

(2) When the water is high, migrating walleyes tend to hug the banks, where current is slower. Important spots are shallow inundated floodplains and gravel flats on the inside of a bend, in relatively shallow water. Distinct drops from 2 to 3 feet or 3 to 4 feet on inside bends become critical in high, cloudy water.

Sediment and debris settle out quicker in eddies, giving walleyes a chance to breathe easier for a time, making floodplains and inside bends even more attractive as a place to hold. In cloudy water, walleyes tend to feel more secure in the shallows. In these conditions, put most casts on the bank and drag them into the water.

(3) When a river is low, walleyes still migrate in the slowest water possible, but the need for security outweighs the need to conserve energy. In clear water, the fish tend to settle down for the day in deeper holes, pools, and runs. The clearer the water, the deeper they hold when resting or feeding. But it’s important to note that river walleyes often rise to feed in 2- to 4-foot shallows during low-light periods (morning and evening) all summer.

(4) In all cases, walleyes migrating in rivers tend to stack up behind barriers. This could be something as obvious as a dam, or something far less obvious, like a long shallow flat no deeper than 2 feet. Where fish become obvious to birds, bears, and humans, they sense the potential for danger.