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Water Resources. Geography 20G. Water Everywhere. Water covers nearly three-quarters of the earth's surface, mainly in oceans but also as rivers, lakes, snow and glaciers.
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Water Resources Geography 20G
Water Everywhere • Water covers nearly three-quarters of the earth's surface, mainly in oceans but also as rivers, lakes, snow and glaciers. • Water is also found in the atmosphere and underground. Over 97% of the earth's water is salty with the remainder in various forms of freshwater.
Freshwater • Freshwater is defined as water that generally contains less than 1000 milligrams per liter of dissolved solids. • Of the world's freshwater, about 99.9% is either found in glaciers and icefields, or is underground. However, the tiny percentage of freshwater we are most familiar with is that found either as surface water (lakes, rivers and wetlands), or which occurs in the atmosphere, or is found in the soil. • According to some estimates, the quantity of groundwater in the earth would cover the entire surface of the globe to a depth of 120 meters. By contrast, the volume of surface water in lakes, rivers, reservoirs and swamps could be contained in a depth of about one quarter of a meter. • Scientists estimate the world's freshwater at over one billion cubic kilometers.
Freshwater • Freshwater is basic to life: it supports plants and animals in almost all ecosystems, even those in deserts. Aquatic ecosystems are perhaps the most obvious evidence of the importance of freshwater: lakes, ponds, rivers, streams and wetlands support a wide variety of species and provide important ecological functions. • Freshwater is also a basic component of human society. Not only does freshwater support resources such as agriculture, fish and forests upon which society depends for food, clothing and shelter, but freshwater also provides a medium for transportation and energy production, governs settlement patterns, provides a major recreational resource for society, and inspires artistic and cultural expression.
Water in the World • This diagram demonstrates just how little of the world's total water supply is fresh water, and the tiny amount of the freshwater that is not in ice nor underground.
Water Issues • Water Pollution • There are three main types of water pollution: physical, biological and chemical. • Physical pollution is the most obvious and least harmful – floating cans, bottles and garbage that make their way into our waterways.
Water Issues • Biological Pollution refers to viruses and bacteria that enter our waterways. • The most common example of this is the entrance of raw sewage into water systems. • Approximately 20% of Canadian cities dump their raw sewage into local waterways.
Water Issues • Chemical Pollution is the most dangerous form of water pollution. It results from potentially toxic chemicals such as herbicides and pesticides entering our waterways. • These chemicals are often tasteless, odourless and colourless – what is worse is they quite often end up in our drinking water.
Water Issues • Loss of Wetlands • Wetlands are very important parts of natural ecosystems. They serve as important sources of groundwater, and as storage areas for floodwaters. They also serve as valuable sites for scientific studies, trapping and waterfowl hunting. • Wetlands are rapidly disappearing in Canada, as they are being drained to make room for agricultural expansion.
Water Issues • Water Diversions • Canada has taken steps to solve water shortages in some regions by diverting water from one drainage basin to another. Traditionally this has been done over short distances only, and often as part of large hydro-electric projects. • Recently the demand for fresh water in the United States has grown rapidly in some of its dryer regions. Pressure has been placed on Canada to divert and sell its excess fresh water to the Unites States. • There is fear that if we begins to treat our water like any other product that is traded under NAFTA, we may eventually lose control of it.
Future Needs • Today, Canadians have an overabundance of fresh water. This will likely change in the future, however. • Industrial expansion and population growth mean that our need for fresh water will continue to grow. • In 2005 we used approximately 130 billion litres of fresh water per day. It is estimated that by next year we will be using over 180 billion litres a day.
