Threats to Water Resources

Water is essential to all life on earth. Water sustains the human population and is vital for all natural ecosystems.  As such, any threat to this important resource, in turn threatens the ecological, social and economic foundations of the Province.  We face many challenges in protecting Ontario’s precious water resources, now and in the future.

Low Water/Drought

Drought is a complex term that has various definitions depending on individual perspectives.  For Ontario Low Water Response, drought is defined as weather and low water conditions characterized by one or more of the following:

• below normal precipitation for an extended period of time (3 months or more), potentially combined with high rates of evaporation, can lower lake levels, streamflows and/or baseflows and reduce soil moisture and/or groundwater storage,
• streamflows are at the minimum required to sustain aquatic life while meeting only high priority demands for water; water wells becoming dry; surface water in storage allocated to maintain minimum streamflows, and
• socioeconomic effects occurring on individual properties and extending to larger areas of a watershed or beyond.
  

As larger areas are affected and as low water and precipitation conditions worsen, the effects usually become more severe.

Find out more about Low Water conditions.

Water Diversions and Bulk Removals

Our water resources are not unlimited. Water is a renewable resource, water supplies being highly dependent on climate parameters such as air and water temperatures, precipitation, evaporation, snow and ice cover. If more water is used every year than is replaced by precipitation our supplies will be threatened. A water use which could threaten our supply is bulk water removals or diversions (water tankers or pipelines and canals which channel water out of the watershed). MNR is responsible for ensuring our supplies are protected from excess demand. One way this is achieved is to manage water use to ensure use does not exceed renewable supplies (see managing our Great Lakes).

Climate Change

Water supplies and climate are linked in numerous ways through the water cycle.  Changes to the range of climate variables such as air and water temperatures and precipitation, anticipated by climate change, would have an impact on available water resources, adding to the normal swings (variability) we experience in water supplies. Find out more information on how climate change stands to influence our water resources...

With the added stress of climate change, computer projections suggest a greater potential for low water periods, particularly in later summer and early fall. Managing our water supplies sustainably could become increasingly important if supplies become more variable. 

Climate change could place an additional stress on water supplies making it even more important and difficult to ensure that we manage water use to ensure use does not exceed renewable supplies.

Find out more about climate change and water resources.

• Visit MNR's Climate Change web site