Water Quality Basics

Water is an essential component of life.  Every living organism on earth, from bacteria to humans, must have water in some form in order to survive.

Having a reliable supply of clean water is important for our health, the environment and recreational activities.  Water provides food, water and shelter for plant and animal communities.  We also use water to produce electricity, grow food, wash our clothes, for recreation and much more.

Distribution and Movement of Water

While water covers 75% of the earth's surface, very little of this water is readily available to humans.  We require fresh water for drinking, as well as for many of our activities such as growing food and watering livestock.  However, fresh water makes up only 3% of the water on the earth’s surface.  Of this 3%, only 0.3% is easily accessible, with much of the fresh water being contained in ice caps, glaciers and as groundwater.

The total amount of water on earth is constant; however, water is always moving and changing forms.  This means that the water you drank at breakfast may have fallen as rain half way around the world a year ago, or may have been used by a dinosaur 100 million years ago.  Because the water that we have today is the same water that we will have tomorrow and one hundred years from tomorrow, it is important that we take good care of what we have.

The continuous movement of water is known as the hydrologic or water cycle.

What influences water quality?

Water quality can be affected by many factors within a watershed, including climate, landscape and human activities. 

The vegetation, geology and hydrology of an area can have a dramatic impact on surface water quality.  For example, the water of a fast moving

mountain stream will be much different then a slower moving prairie stream.

Human activities can also influence water quality. 

Rain can wash materials from our landscape, such as oil, salt, fertilizers and pesticides into our waterways. Altering the landscape, through such things as logging, agriculture and road construction may also impact the health of our waterways.  In this way both urban and rural land uses can have a dramatic influence on water quality.  While we can’t eliminate all of our sources of water contamination and disturbances, we can take steps to educate ourselves and reduce our impacts. 

Water Quality Monitoring

There is no single or simple measure of water quality.  Water quality is evaluated differently depending on what the ultimate use of the water is.  For example, water quality may be evaluated based on:

aquatic life
drinking water
recreation
agricultural uses

When testing water quality, we can focus on three broad categories:

physical characteristics: such as temperature, colour, suspended solids and turbidity

chemical characteristics: such as nutrients, minerals, metals, oxygen, and organic compounds

biological characteristics: such as the types and quantities of aquatic plants, animals, algae, bacteria and protozoan parasites.

During AWQA Day, we focus on the first and second categories: physical and chemical characteristics.  By looking at temperature, dissolved oxygen, pH and turbidity we are measuring water quality characteristics that can have important implications for fish and wildlife habitat, outdoor recreation and human health. 

More Information

Alberta Environment
Water on the Web
Water Quantity and Hydrology