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Drought's Impact on Iowa Trout Streams Could Intensify

The attention often centers on agriculture when a drought hits. But new Iowa Department of Natural Resources numbers show the state’s stream flows are well below normal and groundwater levels are reaching historic lows. There's a ripple effect in how the drought will affect the state’s fish.

"The only thing we have to relate to is history and history tells us if you go back to 1988 and ‘89," said Manchester Fish Hatchery Manager Dave Marolf. "For the farmers 88 was much worse, they had a much poorer crop than they did in 89, but here at the fish hatchery we didn’t see the full effect of the drought 88 until 89 when it stayed dry.”

Some streams here in northeast Iowa saw water temperatures over 80 degrees this summer. While it’s not as extreme as the Des Moines River’s 97 degrees that killed 40,000 sturgeon, it’s still a dangerously warm for trout.

“Those areas receive water almost exclusively from groundwater and the cold water holds more oxygen than other warmer water," said Iowa State Fisheries Extension specialist. "In those areas you would expect to see less pollution so they’ve sort of adapted their lifestyle to live in those pristine environments.”

Patillo said   these coolwater streams in northeast Iowa are unique to the state and are home to three species of trout: the exotic rainbow and brown trout and the brook trout.

Water levels are at historic lows for streams across the state. With less water, the streams heat up. This is of course, thanks to the drought.  So that caused Marolf to hold back on almost 15,000 of these trout. The DNR is now slowly releasing the overstock into the northeast Iowa streams. The drought isn't slowing down tourism from fishermen. Marolf said he expects a  record-breaking 40,000 fish anglers next year

How long the drought lasts and how much it affects the state’s fish population is hard to predict. But Harry Hillaker, Iowa’s state climatologist, said drought loves company and with this drought... there’s a lot of company.

“Nationally this has been the most widespread drought we've had since 1955, '56, so a long time since we had a drought over such a large part of the country," said Hillaker. "So that makes it hard to get out of. Everyone’s dry there’s just not as much moisture around… humidity is low it makes it harder to get a rainstorm”

People have learned to do a lot of things to make Mother Nature friendly, like maintaining streams and controlled fish spawns, but when Mother Nature throws a curveball, like this drought... It’s unclear what can be controlled. 

Clay Masters is the senior politics reporter for MPR News.