stick in the mud

This is something new underfoot for the pedestrians and cyclists who frequent the Black Street Gully.

This is something new underfoot for the pedestrians and cyclists who frequent the Black Street Gully.

Those who use the asphalt path and associated metal staircase to get up the clay cliffs will notice something odd on a portion of the right-hand slope as they head uphill.

Dozens of willow sticks have been embedded in the silt cliff adjacent to the asphalt path as it runs up from Black Street.

No, it is not a work of modern art, although it does look very striking.

Nor is it a row of punji stakes to maim and kill tigers such as used to sometimes occur in the Far East.

Instead it is the city of Whitehorse doing some rather clever erosion control along the clay cliffs.

First a little discussion of the terminology involved in this project is in order.

The gully at the end of Black Street is called Puckett Gulch, but only by city officials.

People who actually use it seem to call it the Black Street Gully.

The clay cliffs that the gully goes through are actually composed mainly of silt.

Silt cliffs do not seem to offer the nice alliteration that the words clay cliffs do.

And therein lies a problem.

Silt does have a tendency to go with the flow.

Any time the cliffs become wet, be it from snowmelt or rainfall, the cliffs erode.

The cliff erosion at various places adjacent to the downtown core has become quite extreme.

Erosion is a natural process, but in some places this is not acceptable.

The threat to infrastructure can be costly, as the city and its residents know well.

In the past there was a program to buy out and then demolish some downtown houses that were deemed too close to the cliffs.

There was great concern they would be engulfed by silt eroding off the slopes, either through an avalanche or gradually over time as the cliffs eroded.

In the Black Street Gully case silt is covering the asphalt path and continued erosion could possibly cause problems to the staircase.

The solution involved enlisting the help of Mother Nature.

Long willow sticks have been cut from adjacent willow plants.

This ensures that the willow being used comes from the immediate area and is thus adapted to the local micro climate.

It is also making use of a free local source of material, and not paying tax-payer dollars to truck up expensive plants from down south.

Small holes about a metre deep are drilled into the cliffs, and the willow sticks planted.

Note that the depth of the holes is critical to the success of this project.

The city had discussions with consultants and companies, which have successfully used the willow stick method at other northern locations.

They all emphasized that the one-metre depth of the hole is key.

It would seem that shallow holes do not work as well in getting the willow sticks to take root.

The fine weather this year has also added a level of complication.

The willow has been watered a couple of times a week.

Had this project been done last year no watering would have been required.

Use of local sticks, deep holes and occasional watering has led to success.

A quick visual inspection reveals that at least half of the willow sticks are now leafing.

This means that they have taken root.

Given the rate at which willow grows these sticks will soon turn into the normal willow plants that are visible throughout the Yukon.

They will provide shelter for additional natural plants as seeds and pollen find shelter beneath the new willows.

Where plants grow they hold the surface soil, in this case silt, in place.

Thus the clay cliffs will become stabilized, and the erosion problem diminished.

This project is a bit of an experiment.

Should it be successful, the top portion of the eroding slope by the Black Street Gully adjacent to the asphalt path will be revegetated in a similar manner.

At the moment, only the bottom third or so of the cliff is being planted.

It is worth noting that the sticks have been planted straight into the silt without the benefit of adding topsoil or compost.

To speed up the process of getting the willow to take root and having additional plants sprout compost could be used.

This compost would be from the city of Whitehorse’s composting facility, a great use of a locally made product.

Other areas along the clay cliff escarpment area will potentially be stabilized using this method.

For more information on planting willow sticks to combat erosion contact Douglas Hnatiuk with the City Parks and Recreation Department at 668-8662.

Lewis Rifkind is a Whitehorse based part-time environmentalist.