Natural and human Factors Affecting our Water Supply

The Rising and Falling Water Table
1. If more water leaves a watershed than enters it, a shortage will result. The usual water levels in lakes and rivers will start to drop. Below ground, the level of the water table will drop as the amount of ground water decreases.
2. If more water fills a watershed than leaves it, it could result in floods. When it rains, water soaks into the ground, filling up the layers of soil and aquifers. If more rain occurs, the water will keep on rising resulting in the flooding. Flooding can cause the water to become contaminated.
3. Both natural and human factors can affect our water supply because of change in the water table. The result can be less water, or too much water that it becomes contaminated.
Natural Water Table Changes
1. Flooding
  1. Can be brought on by heavy rainfall, ice-jams, sudden spring thaws and storms.
  2. Flash floods are floods that come without much warning. They are caused by heavy, concentrate rainfall such as the kind you would see during a thunderstorm.The rain flows rapidly across bare ground and paved surfaces, causing the water level in storm drains to rise, overflow and back up. Surface flooding then occurs
2. Drought
  1. Long periods of little or no precipitation. They cause watersheds to lose water and lakes and rivers to experience falling water levels.
  2. The upper surface of the water table gradually drops as less ground water collects. Communities must restrict water use during these drought periods.
3. Earthquakes
  1. Can affect the water table directly. In areas that are prone to earthquakes, scientists have noticed a drop in the water table by as much as 1m.
  2. A disruption like that in the water table can also cause ground water to become cloudy, affecting its potability.
Human Causes of Water Table Changes
1. Overuse of Wells
  1. More than 25 percent of Canadians rely on ground water for their water needs. Most of them live in rural areas.
  2. The water cycle naturally recharges our groundwater supply.
  3. An unusually dry summer or a winter with little snow results in less water sinking into the ground and collecting in aquifers.
  4. Overuse of wells can deplete underground aquifers, often for long periods.
2. Farming and Industry Practices.
  1. A reason why many industrial plants are located beside a river or lake is that many large scale farms and industries need immense quantities of water in their operations. After the water is used, it is discharged back into the environment.
  2. The used water may be discharged directly into a water body, the atmosphere, a wastewater drainage system, or a ground filtration system.
  3. Sometimes less water is put back into the natural system than was removed.
  4. Examples of large scale water use are irrigation, power generation, and industries such as pulp and paper production and mining.
  5. A particular concern is the oil sands development in northern Alberta's Athabasca River basin is of particular concern because of the enormous effect it is having on the supply and quality of fresh water in the region.
3. Water Diversion and Export
  1. The bottled water industry removes large quantities of water from our water supply. The majority of Canada's bottled water industries are in Ontario, Quebec, and British Columbia.
  2. Millions of litres of water are removed from a variety of sources. If more water is removed than replaced, the height of the water table will be affected. Also, water may be pumped out of one location and shipped to another province or country.

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Natural and human Factors Affecting our Water Supply

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