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Beavers unlikely inspiration in drought mitigation

‘Biomimicry’ brought the Coen farm back from the edge of a water disaster

Beavers unlikely inspiration in drought mitigation

If you look closely at a Coen family photograph taken over 100 years ago, you’ll spot a well in the back corner of the picture. It’s hand-dug, about 20 feet deep — all it took to find drinkable water in 1914.

Today, the farm’s wells are 180 feet deep. Takota Coen told his audience at the virtual Living Soils Symposium that his parents had dug multiple wells. Some produced a bit of water and some had water for a little while and then went dry.

“You couldn’t shower at the same time as Mom was doing laundry or the cows were coming back from the pasture to drink,” Coen said. “My whole life we struggled with water.”

In 2012, Coen returned to his parents’ land near Red Deer Lake, Alta. to make a go at farming. He knew that his farm wouldn’t be viable if they couldn’t solve the water problem.

The farm had been organic since 1988, but the family began researching permaculture — a land management practice that attempts to work with or live in harmony with nature.

He knew there’d been wetlands on his land many decades before, said Coen. He consulted topographical maps to determine where they’d been. The family decided they needed to put the wetlands back.

Coen called the process “biomimicry.” With a series of dams and contoured swales (gently sloped channels), they began to funnel water into ponds. The idea — to slow down the water that arrived via snowmelt (about half of their yearly precipitation) or by rain and to allow it to sink into the land.

A drone shot of a dam and retention pond under construction on the Coen farm with Red Deer Lake in the distance.
 photo: Video screengrab

Coen said they’d ‘harvested’ or gathered about 10 million gallons of water this way over five years. They’ve had one year of intense drought, but they had enough water. In the same year, their region also saw intense flooding but their waterways were able to handle the excess water.

The water table has also risen. Coen’s neighbours have told him their wells are producing more and better-quality water, he said.

Coen likened a dam they built to a beaver’s, and the channels they dug not unlike those beavers dig radiating out from their lodges.

That’s likely not a coincidence.

Unlikely ally

Manitoba farmers have a contentious relationship with beavers. Unlike Coen, whose land hadn’t hosted a beaver in a century, Manitoba doesn’t seem hard up for the chubby chompers.

In 2001, Ian Bell wrote in the Western Producer, that the province’s beaver population was “out of control” and causing millions in damages.

It had been a wet year, and beavers had made flooding worse. Then conservation minister Oscar Lathlin vowed to extend a beaver control program.

In 2017, Interlake farmers were again doing battle with the rodents. A CBC report says the area was in a wet cycle and beavers were making flooding much worse.

A cattle producer told CBC, “they’re destroying a lot of cattle operations up here.”

“The population is exploding,” he added. “It looks like a war zone.”

In 2021, Keystone Agricultural Producers passed a resolution to lobby the province to include beavers in its wildlife damage compensation program.

So Manitoba farmers could be forgiven for being skeptical if told beavers are natural allies, or at least examples, in drought mitigation.

In the same panel discussion as Coen, wetland ecologist Glynnis Hood told the audience she’d worked with Parks Canada in Elk Island National Park (just east of Edmonton) during a terrible drought in 2002. It was the worst drought the area had recorded in 137 years.

“Despite watching wetlands dry up before my eyes, I started to notice that the only ponds that still had water in them were ponds with beavers,” Hood said.

“The drought was so bad that farmers and ranchers were seeking out properties that had beavers on them so that they could find water and some green grass for their cattle.”

When she looked at aerial photos of the region going back to 1948, she found that ponds with beavers had nine times more water in them than those without, even in droughts.

“Ponds with beaver channels and excavated bottoms refilled faster once the rains returned,” Hood said. She showed pictures of two ponds — one with beavers and one without — which were immediately down the road from each other.

After a drought in 2009, the beaver pond was full once the rains returned while the other took two to three years to refill, Hood said.

“Just as farmers dig channels to drain their fields in the spring, beavers dig channels to focus and direct water.”

Farmer and speaker Takota Coen (top right) and ecologist Glynnis Hood (bottom) speak with host Judith Schwartz in a panel discussion during the Living Soils Symposium. photo: Video screengrab

Hood studied the “little aquatic highways” the beavers dug all over Miquelon Lake Provincial Park in Alberta — over 40 kilometres of channels in the 13-square-kilometre park. She observed that when beavers occupied a pond, these ponds grew much larger.

“In areas where beavers build dams, the ponds’ contribution to groundwater storage is significant,” said Hood.

Hood cited researcher Cherie Westbrook from the University of Saskatchewan who found that flooded beaver ponds can contribute to groundwater recharge in the equivalent water volume to a one-in-100-year flood (or more, said Hood).

Hood also has observed beavers in her area dam and trap groundwater instead of streams.

“These beavers are living in terraced ponds and they’re damming groundwater,” she said. “They’re working the whole system, and it is incredible.”

Beavers can also be incredibly destructive, Hood acknowledged. She briefly shared her experiments with “pond levellers,” which in many cases successfully managed flooding around beaver ponds in Alberta’s parks.

It’s a cautionary tale, said Hood. She hears from people who are looking for beavers to import onto their land, and she also hears from people desperate to get rid of them. They’re not suitable for every type of landscape or body of water.

Drought a real possibility

Beavers may be fair-weather friends, but concepts of water storage — the slow, sink and spread model Coen implemented, for instance, may be worth some thought.

During the Living Soils Symposium Merrin Macrae, a hydrologist with the University of Waterloo said based on climate models, Western Canada is likely to see wetter winters and drier summers as climate change progresses.

Macrae showed maps of observed changes in temperature between 1900 and 2012, which showed that the Prairies have seen winter temperatures rise between 3° and 5° in that time, slightly less in spring, and between zero and 2° higher temperatures in summer.

The warming trend is projected to continue, according to climate models, she said. This has implications for snowmelt and water supply going into spring and summer.

This year has thus far shaped up pretty dry. As of Feb. 18, most of agro-Manitoba had received less than 60 per cent of average precipitation — less than 40 per cent in much of southwest and south-central Manitoba.

Despite severe flooding in some areas last summer, most of Manitoba is in a state of moderate to severe drought based on Agriculture and Agri-Food Canada’s drought monitor.

Macrae and co-panellist Odette Menard advocated for cover crops and reside ground cover as ways of keeping more water in the soil and increasing the soil’s capacity to absorb moisture.

About the author

Reporter

Geralyn Wichers

Geralyn Wichers grew up on a hobby farm near Anola, Manitoba, where her family raised cattle, pigs and chickens. Geralyn graduated from Red River College’s Creative Communications program in 2019 and was previously a reporter for The Carillon in Steinbach. Geralyn is also a published author of science fiction and fantasy novels.

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