Fishing & boating

How Rising and Falling Water Levels Affect Fishing

By the Water Level Atlas team · Last reviewed Oct 21, 2026

Changing water levels often move fish. State fisheries biologists generally advise anglers to check whether the water is rising, stable or falling, because that tends to change where fish hold and how they feed. None of this is a rule: every lake and river is different, and local conditions matter more than general patterns.

Why does the direction of change matter?

In an article from the Kentucky Department of Fish & Wildlife Resources, a fisheries biologist sums up the first step simply: see what the water has been doing. Is it coming up, stable or falling? Kentucky's article explains that this tells you a lot about where fish are likely to be.

The same day's level can mean different things. A lake that is 2 ft (0.6 m) below its usual level and still dropping is a different situation from one at the same level that has just started to rise after rain.

What tends to happen when a lake is rising?

According to Kentucky Fish & Wildlife, rising water that floods new habitat draws smaller baitfish into the shallows. Predator fish are apt to follow, and may stay somewhat shallow if the lake then levels off before it starts to fall.

Rising water after heavy rain also tends to be muddy. Kentucky's article notes that dirty, turbid water makes it hard for fish to feed by sight.

What tends to happen when a lake is falling?

Many reservoirs are drawn down on a schedule. Kentucky's article notes that the fall drawdown on many of that state's reservoirs begins between mid-September and early October and usually brings several weeks of falling water. A heavy rain can still make a lake jump up during a drawdown.

The article advises treating falling water as a sign that fish are likely to be retreating to deeper water. Its biologists single out mobile species such as crappie, hybrids, white bass and walleye as being on the move at these times. It also points to one visual clue: damp rings around tree trunks show that water is being let out through the dam quickly.

For more on why reservoirs are lowered, see winter drawdown and guide curves explained.

What about rivers and streams?

On rivers, flow (measured in cubic feet per second, see what is cfs) matters as much as level. The Minnesota DNR's stream conditions page for southeast Minnesota trout streams rates both water clarity and flow:

• Clear: visibility 2 ft (0.6 m) or more.
• Off: slightly off-coloured, visibility between 2 ft and 6 inches (15 cm). The DNR notes some anglers prefer this.
• Muddy: visibility under 6 inches. The DNR describes this as unfishable for most anglers.
• Low, Normal or High: flow compared with what is typical for the time of year.

The same page shows how quickly this can change: rain and snowmelt can turn streams muddy and high within days. The DNR links to USGS streamflow gauges so anglers can check flow before they go. Our how river gauges work guide explains what those gauges measure.

What happens when water is very low?

Low water brings its own changes. The Utah Division of Wildlife Resources explains that a smaller amount of water heats more quickly and reaches higher temperatures, and that warm water holds less oxygen than cold water. That combination can stress coldwater species such as trout. Utah's biologists also note that fish may be found in different places than usual, especially later in the season.

Utah's guidance for anglers during drought includes fishing in the mornings or evenings when temperatures are cooler, using rubber or coated nylon nets, and letting fish recover in the net before release.

Some states restrict fishing when flows are very low or water is very warm. A USGS tool called TroutCast combines long-term monitoring data from Montana Fish, Wildlife & Parks with USGS streamflow and water temperature data to forecast the chance of reaching Montana's drought-related low-flow and high-temperature thresholds. Always check your state's current regulations and closures. See water temperature and fish for more on temperature.

What about high water?

The Minnesota DNR's stream reports show rain and melting snow leaving trout streams with "muddy and high flows", and the DNR rates muddy water as unfishable for most anglers. For boating conditions, see low-water boating hazards and follow the guidance of your state agency and the lake or river operator. If a river is near flood stage, follow official National Weather Service warnings (see flood stages explained).

Using this on Water Level Atlas

Lake pages show the change over 24 hours, 7 days and, on most lakes, 30 days, and a Rising, Falling or Steady badge based on the last few hours. River pages show the flow in cfs, gauge height where measured, and the same 24-hour and 7-day changes. Both page types compare today with the normal range for the date (see normal for the date), so you can see whether the water is unusually high or low for the season. These are measurements, not fishing forecasts.