Thursday, July 26, 2007

Riverdale Ponds Get a Breather


Aerator installed at Riverdale Farm

The Lower Don has very few ponds so the presence of the two ponds at Riverdale Farm offers a welcome respite for passing waterfowl and other wildlife. The prevailing theory is that they are oxbow lakes, created when the Don River used to meander over the floodplain, before the so-called Don Improvement project which straightened the river in the late 19th century.

During the period when they were part of the old Riverdale Zoo, water was pumped in via a fountain in the upper pond. The ponds were home to captive geese and swans. In the mid 1970s the zoo was relocated to a large facility in eastern Scarborough in the Rouge River watershed. Since then the ponds have languished, mostly unused except as a dumping ground for koi and red-eared slider turtles.

The ponds were until recently fed by tap water but about five years ago this flow was shut off. While the result is more natural, the low flow situation has resulted in the ponds completely covered by duckweed by mid summer. In addition a large amount of decomposing leaf litter at the bottom of the ponds has resulted in anoxic conditions which means that very little aquatic life inhabits the ponds.

Enter the idea for the pond aerator. Basically it blows air bubbles into the water. The theory is that the air will partially dissolve into the water which will not only make it more livable for aquatic organisms but also accelerate the decomposition process of the accumulated leaf litter. Currently the aerator is only turned on at night.

Don't expect any overnight changes. The current conditions have been created by several years of neglect - it may take a year or two before any changes become noticeable. While not the greatest solution, it is still a solution, ie. something to be tried. And you can't fault them for that.



Aerator is turned on only at night, thus the poor quality of this photograph

2 comments:

Cup Plant said...

Can we assume that the aerator is actually working every night? That was still a question last week at the Riverdale stewardship.

Cheryl-Stewardship Coordinator said...

Hey everyone! Yes, the Riverdale Aerator is working every night. It's hooked up to the street lights which turn on by photo cell.
I've had people out to check and it is working.