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On-farm reservoirs good for the environment and farmers’ pocketbook too

A pilot project near Elm Creek is testing an on-farm reservoir as an economic way to ease the threat of flooding and reduce nutrient losses into Lake Winnipeg

Culross farmer Carl Classen has partnered with the LaSalle Redboine Conservation District to build a reservoir to collect and store run-off from a half section and then put it back on his land later. Classen benefits from improved drainage, nutrient retention and the potential for small-scale irrigation. If a lot more farmers did the same less phosphorus would end up in Lake Winnipeg, there’d be less strain on the provincial drainage system and reduced flooding.

Like most farmers in the Red River Valley, Carl Classen sometimes has too much water on his fields, then not enough.

But he has a two-pronged solution: Improve drainage to get water off his land faster, but instead of sending it downstream to potentially flood someone else, he’s storing it in a reservoir to irrigate the same fields later.

“Because we have intensive crop management and because we have water issues we need to manage more of it,” said Classen. “We also need to think about the dry years when the aquifers get lower.”

Holding back water also means holding on to expensive nutrients, instead of sending them to Lake Winnipeg, where phosphorus loading is causing massive blue-green algae blooms.

“I want to just do my small part and improve things for people downstream and oceans far away,” said Classen.

“There’s so much we can do and there’s so much we don’t understand that we need to learn. But we have to start someplace and so I’m taking a stab at it and hopefully it’s going to catch on. I can’t see why it wouldn’t.”

Last spring, Classen hired a contractor to build a reservoir 306 x 306 x 20-feet deep on the low end of a half section of his land. A smaller dugout beside it collects the run-off, which then is pumped into the larger reservoir.

The LaSalle Redboine Conservation District contributed around $40,000 to build the reservoir, said district manager Justin Reid.

Joel Classen works at calibrating a tile drainage plow near Culross. photo: Allan Dawson

“We were willing to put in a little more than we normally would’ve as a per-acre-foot cost simply because this was a pilot project,” Reid said. “Our board is willing to do more similar projects but we’re going to be looking at different designs and different construction styles where we can maybe get the same results with a less expensive design.”

The district will test the water to see how many nutrients are collected and then returned to the land.

“We think it can have a pretty significant impact on the drainage network,” Reid said. “If there are more people holding water on the land, the less water that needs to move through the drainage network at any given time.”

There’s also an on-farm drainage benefit. Before the reservoir, Classen couldn’t drain excess spring run-off or summer downpours because the Bryson drain that runs by his farm, and municipal ditches, were full of water.

“If I can drain the water faster I have a chance for a better crop,” he said.

While the environmental and production benefits are clear, the economics are less so.

“The only way this makes sense to the farmer is from direct, on-farm benefits,” said David Lobb, a professor of landscape ecology at the University of Manitoba and an expert in watersheds.

“We’re talking about trying to get 20 per cent or maybe 50 per cent of the farmers in the Red River Valley to do it because it makes them economically competitive.”

If they do, it could significantly reduce the amount of phosphorus going into Lake Winnipeg.

Joel Classen (l) Carl Classen and Simon Knutson stand beside a tile plow. Joel and Simon are Carl’s son and son-in-law, respectively. All are part of Northern Plains Drainage Systems in Carman. The company sells plows and teaches farmers how to install their own drainage tile. photo: Allan Dawson

Although not the only culprit, farming is a significant contributor of phosphorus heading into the lake. But farmers are already about as efficient as they can be when applying nutrients, Lobb said.

“Even if nutrient application to agricultural land was to stop tomorrow, nutrients would continue to run off the land for many years,” he said. “If you want to control the nutrients that get into the lake, you have to control the water.”

Part of the economic equation is irrigation. Classen said the reservoir can hold 6.6 million imperial gallons, enough to put one inch of water on 300 acres. That doesn’t sound like much, but some years it can make a big difference, Classen said.

“If we start off with adequate moisture in the spring, one extra rain in a dry period at the right time can be beneficial.”

Irrigation, in combination with improved drainage, also reduces the risk in growing higher-value crops. Classen, who already grows soybeans, wants to try edible beans, which need to be on well-drained soil.

Farmers in the Red River Valley can lose five per cent or more of their crop and inputs due to delayed seeding or heavy summer rains, Lobb said.

“If you’ve got 100 per cent of your area draining well and don’t have those inundated areas you’ve gained a lot of crop on some years,” he said.

Getting rid of water has been a priority for well over a century.

The region east of Elm Creek where Classen farms was once marsh country. It was drained in the early 20th century and in recent years, laser-guided scrapers eliminated the remaining sloughs and potholes that held water and recharged aquifers.

But attitudes will change if there’s a prolonged dry spell, said Classen.

“We’ll be asking the government to supply us with water from some big dam project miles and miles away,” he said.

“We shouldn’t be treating water like waste,” added Lobb. “We just don’t have enough of it.”

But there are questions which need to be answered, he said, including construction and maintenance costs, safety and salinity. (He estimates a reservoir able to store water from a section of land would take up about six acres.) However, widespread adoption of on-farm reservoirs would lower the cost of the provincial drainage system, Lobb said.

Classen said he hopes his reservoir will be the first of many.

“My point in doing this is to start the idea that farmers can store their own water,” he said. “It’s what we need to do in the long term.”

About the author

Reporter

Allan Dawson

Allan Dawson is a reporter with the Manitoba Co-operator based near Miami, Man. Covering agriculture since 1980, Dawson has spent most of his career with the Co-operator except for several years with Farmers’ Independent Weekly and before that a Morden-Winkler area radio station.

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