BE WARY OF THIN ICE AND WATCH FOR AERATION PROJECTS

Released on December 22, 2005

Saskatchewan Environment advises people to be cautious on all frozen lakes and rivers, especially on water bodies that have aeration systems.

There is often thin ice and open water near an aeration system. Water bodies with aeration systems are posted with warning signs and people are advised to stay clear of these posted areas.

Aeration systems pump fresh air into the small, shallow, highly productive lakes or reservoirs. This is done to prevent what is called "winterkill". Winterkill occurs when the plants in a water body either die or reduce their oxygen production. This can happen when ice and snow cover reduces the amount of sunlight reaching the plants and photosynthesis slows down or stops. Without enough oxygen, the fish die.

The constant flow of fresh air from the aeration system raises the oxygen level in the water under the ice and increases the survival rate for fish. Aeration systems usually operate between December and March. A list of water bodies with aeration systems and contact names for each area is attached.

Changing temperatures, combined with the amount of snowfall and slush in some areas can contribute to unsafe ice conditions. Extreme caution should be taken while traveling on the ice this winter.

Here are some ice facts people should be aware of:

•ice strength should never be judged by appearance alone;

•ice thickness can sometimes vary from safe to unsafe within a metre—ice thickness is seldom uniform throughout a water body;

•changing temperatures can cause thermal cracks, and pressure ridges, which are all indicators of unsafe ice;

•slush indicates that ice is eroding from above and below at an advanced rate;

•large, deep lakes take longer to freeze and are slower to melt than smaller lakes;

•currents in a river or creek make ice approximately 15 per cent weaker than lake ice; and

•heavy snowfall in some areas of the province can reduce the bearing capacity of the ice; the weight of the snow often causes slush and/or flooding—snow also acts as an insulator, which slows the freezing process.

More information on ice safety can be obtained from the Canadian Red Cross.

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For More Information, Contact:

Art Jones Environment Regina Phone: (306) 787-5796 Cell: (306) 536-8452