With flood season underway in the Red River Valley, biologists say they expect the impact on fish and wildlife to be minimal.
That’s generally the case with flooding, at least in North Dakota.
“It’s definitely not something that gives us a lot of concern as far as wildlife species,” said Jeb Williams, wildlife chief for the North Dakota Game and Fish Department in Bismarck. “The flooding impacts in North Dakota are much more — and rightfully so, they should be — focused on human protection and things like that versus wildlife.”
No doubt deer and other wildlife that live along riparian areas are driven from their habitat during flooding, but that’s generally a short-term situation, Williams says.
“It’s a very productive wildlife habitat, but they disperse, they move away from those areas during the high water period, and generally speaking, you don’t see any major impacts,” he said. “Long story short, we don’t see any major impacts associated with (river) flooding in North Dakota simply because they’re short in duration.”
From a fisheries standpoint, a rise of a couple feet in a prairie lake “is always a sweet deal,” said Greg Power, fisheries chief for the North Dakota Game and Fish Department in Bismarck. Since a wet cycle that began in 1993, the number of fisheries in North Dakota has risen from 180 to 440, Power says. Former shallow duck sloughs in many parts of the state have grown into 2,000-acre lakes that are 20 to 30 feet deep, he said.
While he’s cautious to say too much about flooding, given the effects it can have on people’s lives, Power says high water without question has had a positive biological impact on North Dakota’s fisheries.
That’s especially true on so-called “opportunistic” lakes that have sprung up during the wet cycle. Such prairie pothole lakes tend to be rich in nutrients and forage that make fish grow fast.
“The invertebrate base is amazing,” Power said. “Our prairie pothole walleye growth is something we never thought would happen in North Dakota. In the first half of my career, (the benchmark) was always 6 inches the first year, 10 inches at year two and maybe pushing 14 at year three. Now, we’re getting 14-plus inches in a year and a half in some of those lakes, especially south of (Interstate 94).
“In the broadest picture for North Dakota, a prairie state, flooding has meant everything for its fishery.”
That’s not to say there aren’t negative impacts. Just as flooding can damage homes and infrastructure such as roads and bridges, Power says boat ramps and other public access amenities also can suffer from too much water.
That was the case in 2011, when extensive flooding occurred along the Missouri River, he said.
“The biggest project we ever had was as a result of the aftermath of the 2011 flood south of Bismarck,” Power said. “We spent well over $1 million just to protect that MacLean Bottoms site, boat ramp and parking lot.”
In the short term, species such as pike and perch are the first to benefit from flooding because they favor newly inundated vegetation for spawning, Power says. Even this year, despite a slow melt that likely will limit runoff in many parts of the state, pike and perch could see stronger hatches than in recent years, he said.
Walleyes also do well in the long term with high water conditions.
“You look at Devils Lake, the better year-classes we have had are the ones that we’ve had good runoff — especially in Mauvais Coulee, Channel A and the western coulees,” Power said. “I believe 2009 was a banner year-class for walleye, and we also had large runoff. They run (upstream) and they find places to spawn and get the job done.
“And the same with Sakakawea and Oahe. Over the years, when we have rising pool (levels) in the spring, stable but preferably rising, we’ve noted good year-classes. In the years we’ve had a dropping water level, never do you get a good year-class.”
Besides damage to infrastructure, another downside to flooding occurred in 2011 along parts of the Missouri River System with the loss of smelt being washed over dams, Power says, a phenomenon known as entrainment.
“They lost, I think it was 95 pecent plus of the smelt that one year,” he said. “Oahe as a whole, the recovery of smelt still is not back to what we were” before the 2011 flood.
Fish that instinctively run up creeks and ditches during floods also can get stranded when the water recedes, Power says. That’s what happened in 1997, he says, when pike near Bismarck ran up flooding creeks and sloughs and ended up in alfalfa fields northwest of Steele, more than 40 miles away.
“Farmers found a number of pike that made this spawning run — phenomenal,” Power said. “Flows just dropped off and stranded the pike in the fields.
“You hear that in pike and carp, but you don’t hear it in walleye,” he added. “Walleye tend to be deeper, and they don’t go up the creeks, really small creeks. They’re in a little bigger river systems, at least in North Dakota, and most of our walleye spawning we get is not very dependent on creeks, and it’s mainly in the lakes themselves.”
Among wildlife species, flooding conditions generally have the greatest negative impact on waterfowl and other ground-nesting birds that lay their eggs near wetland or riparian areas.
“You see some Canada geese nesting in places that are dry earlier in the spring and then as water continues to go up, they lose their nest,” Williams, the Game and Fish wildlife chief, said. “We even see that with pheasants, too. But the fortunate thing about most birds like that is they’ll renest. … Their instincts will continue to kick in and tell them they’ve got to get another nest going, and they’ll do that. Generally speaking, it’s probably less eggs than were in their first go-round.”