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Published June 07, 2009, 12:16 AM

Views differ on farm drainage’s role in flooding

The role that farm drainage plays in area flooding has long been a hot-button issue.

By: Jon Knutson, INFORUM

The role that farm drainage plays in area flooding has long been a hot-button issue.

But debate became even more heated after record flooding this spring, at least judging by comments on online chat sites and elsewhere.

The way some commentators see it, farmers contributed big-time to flooding.

But others say agriculture is getting a bad rap and bears little, if any, responsibility.

Who’s right?

Well, the experts don’t agree, either.

“Farmers don’t cause flooding. Don’t blame them,” said Jeff Volk, president of West Fargo’s Moore Engineering and a veteran player in area water management issues.

But Bethany Kurz, senior research manager for the University of North Dakota Energy and Environmental Research Center in Grand Forks, said many water management experts believe farm drainage does contribute to flooding.

“The consensus is, it does have an impact,” although no one knows just how much, she said.

She isn’t aware of any study that specifies the extent, if any, to which flooding and farm drainage are linked.

But she’s hopeful that such a study – most likely using data collected by LIDAR, or light detection and ranging technology – eventually will be made.

Highly accurate LIDAR elevation data can play an important role in flood mapping and research, according to the U.S. Geological Survey web site.

Such a study could help clarify the core question in the debate over farm drainage:

Does it cause surface water on fields to flow faster and sooner into rivers, worsening flooding?

Again, the experts are divided. And, once again, there seem to be no studies or firm statistics that can prove the case either way.

Genevieve Thompson, executive director of Audubon Dakota, which has a Fargo office, thinks there’s likely a connection between farm drainage and water reaching rivers faster and sooner in wet years.

Audubon Dakota’s mission is to conserve and restore natural ecosystems focusing on birds, other wildlife and their habitats.

But Hans Kandel, a North Dakota State University Extension Service agronomist who works with farm drainage, sees no link between farm drainage in the Red River Valley and water getting to rivers quicker and sooner.

Given the natural slope of land here, water would drain to rivers even without drainage, he said.

He pointed to massive Red River flooding in 1897 – when farm drainage was less common in the area than it is today – as evidence that farm drainage isn’t a factor in flooding.

Thompson said that argument often is used.

However, too little is known about precipitation patterns and melt rates in 1897 to draw valid comparisons between flooding that year and today, she said.

Why farmers drain

Virtually all area farmers drain fields to some extent and began doing so as soon as the region was first colonized by Europeans, Kandel said.

Draining fields helps reduce crop losses when heavy rains come during the growing season, he said.

Drainage also can help farmers plant crops earlier in the spring.

Every growing season is different, so planting fields early doesn’t guarantee a better harvest than ones planted later.

Nonetheless, fields planted early typically fare better.

For instance, North Dakota wheat yields normally drop 1.5 percent for each day a wheat field is planted after May 15, according to information from the NDSU Extension Service.

Such losses can eat up most or even all of farmers’ profit, Kandel said.

Ag producers would benefit from even more draining, he said.

“Farmers already are leaving a lot on the table,” he said.

He cited a study of farmland in northwestern Minnesota in 1995 that found excess moisture cost farmers there an estimated $203 million.

Too much water in fields reduced wheat yields by 15.2 bushels per acre, corn yields by 25 bushels per acre and soybean yields by 7.2 bushels per acre, according to the study.

Perceptions differ?

Nobody knows for sure whether farm drainage does or doesn’t contribute to flooding, said Eric Aasmunstad, president of the North Dakota Farm Bureau and a Devils Lake farmer.

But it is certain that agriculture is a vital part of the region’s economy, he said.

Agriculture accounts for about a quarter of both North Dakota and Minnesota’s economic base.

Aasmunstad is among many in agriculture who think some urban residents increasingly fail to recognize how much ag means to the region.

Curtis Stofferhan, a rural sociologist at the University of North Dakota, said he’s not aware of any study or statistics to prove or disprove the idea that urban and rural perceptions are drifting apart.

In any case, Aasmunstad said he’s confident ag’s importance will continue to be valued by people who really understand the region.

“Wiser heads will prevail,” Aasmunstad said of the debate over farm drainage.

Kurz and Thompson said they recognize the importance of agriculture, but also want more information on the potential connection between flooding and farm drainage.

“We need a good hydrologically based study” that examines the issue, Thompson said.


Using terms correctly

Don’t use “tile drainage” and “farm drainage” interchangeably.

Farm drainage refers to the general practice of removing excess moisture off fields, typically through surface ditches.

Tile drainage is a specific type of farm drainage.

Tile drainage involves installing underground pipes in fields to regulate subsurface water and help plant roots develop properly, boosting crop yields.

Once, short lengths of clay pipes known as tiles were used. Plastic tubing with small perforations are now used.

Excess subsurface moisture slowly seeps into the tubing and is taken to a ditch or other outlet.

Tile drainage, though fairly common in some parts of the country, is little used in western Minnesota and North Dakota.

Hans Kandel, a North Dakota State University Extension Service agronomist who works with tile drainage, said he isn’t aware of any estimate of how many acres in the region are tiled.

Because tile drainage is relatively rare in this area, “it really isn’t an issue here” in the debate over whether farm drainage and flooding are linked, said Genevieve Thompson, executive director of Audubon Dakota, which has a Fargo office.


Readers can reach Forum reporter Jonathan Knutson at (701) 241-5530

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