Friday, July 17, 2009

Wicking Water

Just south of the Queen Street bridge some odd looking construction is occurring. There appears to be a forest of silver ribbons poking out of the ground. What are they doing? This technique is called wicking and it is used to remove moisture from the ground.

This area is the northwest corner of the future Don River Park and the western portion is being anchored by what is officially known as a "flood protection landform". This is a kind of levee or berm and is meant to protect the West Don Lands from serious flooding on the order of a Hurricane Hazel size storm. The construction of the berm requires that a large amount of earth be piled in one place. Before that can be done, the ground beneath it must be dried out and compacted. The easiest way to dry out the ground is to insert these silver coloured plastic strips into the ground. Using capillary action, the water in the soil travels to the surface where it evaporates into the air. Once the soil is dried out sufficiently then the new soil can be placed on top. Dry soil compacts easier and has less chance of shifting or moving later on, which is something you don't want to happen for a device that is meant to hold back large amounts of water.

Ribbon forest

Silver coloured wicking strips

The berm is expected to be completed sometime this fall. Once complete, construction of the park and the new neighbourhood to the west can commence.

1 comment:

Anonymous said...

Thanks very much for this. I had noticed these little strips and wondered what their purpose was .... and now I know!!

Les Redman