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Have you ever thought about where your drinking water comes from? Most of us never give this question a thought. Yet, the sources of our water tell us a lot about its quality.
The Importance of Water Sources
Very early in the development of civilizations, people recognized the importance of finding reliable water sources. A clean, constant supply of safe drinking water is essential for every community. Consequently, the earliest civilizations developed near sources of clean water.
As time passed, people began to migrate and settle in areas many miles from a reliable water source. So they developed delivery systems that drew water from those distant sources. The Roman aqueducts are an excellent example of such a delivery system.
Today, people in large cities frequently depend on surface water sources, such as lakes, rivers, and reservoirs, for their drinking water. Sometimes these sources are close to the community. At other times, water suppliers get their water from sources many miles away.
In either case, when you think about the source of your drinking water, it's important to consider the entire watershed in which the source is located. The watershed is the land area over which water flows into the river, lake, or reservoir.
In rural areas, people are more likely to drink ground water pumped from a well. These wells tap into aquifers or natural reservoirs under the earth's surface. These aquifers may be only a few miles wide, or may span the borders of many states. As with surface water, remember that activities many miles away from you may affect the quality of ground water.
Both public and private water supplies can be drawn from a variety of sources. Different sources of raw water demand different treatment methods to render it fit for human consumption.
Deep Groundwater Sources
The water emerging from some deep groundwater sources may have fallen as rain many decades or even hundreds of years ago. Soil and rock layers will naturally filter the groundwater to a high degree of clarity. Deep groundwater may emerge as springs. In places where the water does not emerge as springs, water suppliers will often bore wells to extract it.
Usually, groundwater has a very high bacteriological quality. Because the water passed through layers of soil and rock, it may also be rich in dissolved solids including carbonates and Sulfates of Calcium and Magnesium.
Depending on the strata through which the water has flowed, other ions may also be present. These could include chloride and bicarbonates. Often, water from deep sources requires special treatment to remove its iron or manganese content to make it pleasant for drinking, cooking, and laundry.
Seepage of surface water recharges these deep groundwater sources. This seepage introduces industrial, chemical, animal and human contaminants into these underground aquifers. As these contaminants merge with natural elements in the water, health threats are introduced and disinfection is required.
Shallow Groundwater Sources
While deep groundwater lays far below ground level, shallow groundwater travels in streams within a few hundred feet of ground level. Access to shallow groundwater is usually through wells or boreholes.
The bacteriological quality of these shallow sources can vary depending on the nature of the underground reservoir. A variety of soluble materials may be present including potentially toxic metals such as copper or zinc. In some places, shallow ground water sources contain unacceptably high levels of Arsenic contamination.
Upland Lakes and Reservoirs
Typically, municipalities place upland reservoirs in the headwaters of river systems, above any human habitation. They often surround them by some form of protection zone to restrict the opportunities for contamination.
Bacterial and pathogen levels are usually low, but some bacteria, protozoa and algae will be present. Where uplands are forested or are peaty, humic acids can give the water a brown color. Many upland sources have low pH which requires adjustment before the water enters the supply.
Rivers, Canals and Low-Land Reservoirs
Lowland surface waters primarily come from rain runoff. As rainwater washes the streets of our cities and filters through landfills and farmlands, it picks up a significant bacterial load. It may also contain algae, suspended solids and a variety of dissolved elements.
Conclusions
All water sources contribute to water contamination. The source of your water determines the kind of contaminants it carries.
While water treatment facilities neutralize most of the contaminants, some escape and end up in your drinking water. Many of these contaminants are harmless and, at most, give the water a bad taste or odor. Other pose potential health threats.
To protect yourself and your family from these potential threats, we recommend the use of a home water filtration system to assure that your drinking water is clean.
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