Winnipeg Free Press - PRINT EDITION
Wetlands good flood-fighters
Also offer economic spinoffs
It's easy to point fingers when it comes to finding blame for the 2011 floods. But for the most part, it's not a very productive exercise.
What are we going to do? Pass a law banning the kind of precipitation that has filled lakes, aquifers and soils to overflowing? Or shake our fists at our ancestors, who made the fateful decision to settle on what was once a lake bottom? We can debate till the cows come home whether this is just a wet cycle or the climate is really changing.
We can always blame the government. But quite frankly, when you have walls of water coming at you from several directions like Manitoba faced this spring, there are no right or wrong answers, just a whole bunch of difficult choices.
The only factor in Manitoba's predicament this year that's up for negotiation is whether we need to have all that water coming at us at the same time.
There is ample research to suggest land and water management practices, while not the sole cause, are a contributing factor to the scale of flooding that is occurring with increasing frequency in Manitoba.
Up to 70 per cent of the wetlands across Western Canada have been lost or degraded as generation after generation of farmers has responded to economic pressure to squeeze every last acre into annual crop production.
Aside from providing wildlife habitat, those sloughs and potholes stored water. The more water left the wetlands, the more effort went into "improving" drainage. When we're all trying to flush at the same time, there are obvious repercussions for the system.
A case study by Ducks Unlimited on the Broughton Creek watershed in western Manitoba concluded drainage over nearly four decades increased the peak flows from the watershed by 37 per cent and the steam's total flow by 62 per cent. The phosphorus in the runoff water increased by 32 per cent and nitrogen by 57 per cent.
Research sponsored by the Red River Basin Commission suggests a million acre-feet of temporary storage at a cost of about $1 billion would reduce peak flows on the Red River by 20 per cent -- enough to spare Fargo the cost of a Winnipeg-style floodway. What would a 20 per cent reduction in peak flows have accomplished in Manitoba this spring?
Small dams on the South Tobacco Creek watershed near Miami are credited with reducing peak flows off the Manitoba Escarpment after a major rainfall by as much as 90 per cent.
In North Dakota, researchers back in 2002 studied the "waffle" concept that's currently been implemented as an emergency measure in Manitoba and concluded it's a feasible flood-mitigation strategy.
Research also tells us the biggest flush of the nutrients polluting this province's lakes occurs during flood events.
This isn't about blaming farmers for draining wetlands. Nor is it about commandeering farmland as an emergency reservoir in a last-ditch gamble to avoid more catastrophic losses elsewhere.
This is about seizing an opportunity to befriend our water enemy, while gaining ground on three priority issues -- flood mitigation, cleaning up Lake Winnipeg and economic development.
"We are definitely world-class with flood-fighting activity. Now I think the opportunity is there for us to show the same kind of leadership where we combine the role of flood planning and mitigation with harvesting co-benefits," says Hank Venema, who heads up the Water Innovation Centre at the International Institute for Sustainable Development (IISD).
If farmers were paid to store spring runoff as part of a long-term strategy, the acres devoted to that use might not produce annual crops, but they could still produce something -- like perennial biomass.
Perennial crops, ranging from grasses to cattails, make use of nutrients that are otherwise dumped into our lakes. Scientists studying Netley Marsh at the south end of Lake Winnipeg found by harvesting cattails in the fall they could reduce phosphorus released into the lake by up to 60 per cent.
What do you do with cattails? For a start, you pellet them and use them as heating source, which displaces coal with a renewable, more environmentally friendly resource. Plus, 88 per cent of the phosphorus can be recovered from the ash and returned to the land where it is needed as fertilizer.
Flood mitigation has cost Manitoba a billion dollars over the past 10 years. The economic spinoffs from this approach could put money back into the economy instead of draining it on more sandbags, soldiers, diversions and dikes.
"It's a different way of thinking about land usage," Venema says.
But it's a concept flood-weary Manitobans might be ready to entertain.
Laura Rance is editor of the Manitoba Co-operator. She can be reached at 792-4382 or by email: email@example.com.
Republished from the Winnipeg Free Press print edition May 21, 2011 B10
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