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Willows Offer Stream Bank Fix

Local conservation districts are putting their willows to work.

Planting the hardy, water-loving shrubs along the edges of waterways to prevent erosion and enhance riparian areas offers a lower-cost alternative to the conventional practice of hauling tons of rock, said Armand Belanger, manager of the East Interlake Conservation District.

The magic ingredient is willows, said Belanger, as he and a team of workers were busy near Riverton placing about 3,000 willows on a 300-foot stretch along the Icelandic River, near Lake Winnipeg.

The willows grow almost everywhere, and harvesting them is simple. Three-to five-foot long stems are cut with pruning shears and bundled up for transport. Some are laid in bundles of 10 stems each horizontally along the water s edge to catch sediments and secured with fence posts. Others are planted singly in vertical holes farther up the bank.

Planting the willows involves a few simple tools. Formerly, conservation staff used a rebar pounder to make the holes, but that was a lot of work. Now they use a portable drainage pump, some hose, and a water jet a specially designed spray gun with a six-foot-long, hollow stainless steel tube on the nozzle that is used to drill holes in the mud via water pressure.

Working much like a wash-in sandpoint, the water jet does the work, and making a three-to six-foot hole takes just a minute or so, said Belanger.

An added bonus is that it also saturates the soil so that the willow sticks are more likely to take root when spring comes.

No rooting compound is required, but the willows are more likely to thrive in their new location if the hole is deep enough to reach the water table.

Willows might also help reduce dredging of livestock dugouts, said Belanger, but would require exclusion fencing to prevent the cattle from trampling them.

The conventional erosion-control method of a load of stones or gravel on the stream bank is expensive, creates a zone about as lifeless as a parking lot, and is eventually washed away. Willows, on the other hand, not only maintain themselves and increase over time, but bring life back to the shoreline. Once vegetation takes root, it creates shade and shelter for the myriad organisms that inhabit the zone, and consequently, fish habitat is improved, said Belanger.

There is also some potential for uptake of nutrients, because the plants will use nutrients to grow, he said.

Jeff Renton, interim manager of the Seine Rat River Conservation District, has also used willow stakes to prevent erosion in areas at slight to moderate risk.

The willows grow a substantial amount of root mass that binds the soil together, he said, adding deep-rooted willows don t need watering or weeding to survive.

We ve had almost 100 per cent success, he said. In a week, we can plant 1,000 willows, and that will protect a substantial area.

Rock revetments cost about $100 per foot, but the cost of willows is largely the labour for harvesting suitable stands and planting. Finding tall, straight willows is the hardest part, so the conservation district is looking at establishing plantations.

Using living things to enhance and protect the environment, is catching on all over the world, said Chris Randall, a British student at the U of M s Natural Resources Institute who is writing a thesis comparing bioengineering solutions with conventional practices.

Willows were used in China to control erosion about 2,000 years ago, he noted.

It went out of fashion when labour became more expensive and gas became cheaper, he said.

He has been working with four conservation districts in Manitoba trying out the willow technique, which has become so common in the U.K. that now regulating agencies insist upon it for maintaining riparian areas.

There s quite a few companies in the U.K. that specialize in this kind of thing, and there are specialized plantations that grow willow, he said.

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