White Papers
A History of Water Supply
Water is vital to everyday life, and throughout history people have devised systems to make getting and using it more convenient. Early Rome had indoor plumbing, meaning a system of aqueducts and pipes that terminated in homes and at public wells and fountains for people to use.
An aqueduct is an artificial (man-made) channel that is constructed to convey water from one location to another. The word is derived from the Latin aqua, "water," and ducere, "to lead." Many aqueducts are raised above the landscape, resembling bridges rather than rivers. Sufficiently large aqueducts (water bridges) may also be usable by ships. They are similar to viaducts, but carry water instead of a road or railway. While a road bridge often carries the roadway at a more elevated level than the rest of the road, such a variation of height is not possible for an aqueduct.
Historically, many agricultural societies have constructed aqueducts to irrigate crops. Archimedes invented the water screw to raise water for use in irrigation of croplands. Some of the famed Roman aqueducts still supply water to Rome today.
In more recent times, aqueducts were used for transportation purposes to allow canal barges to cross ravines or valleys. During the Industrial Revolution of the 18th century, many aqueducts were constructed as part of the general boom in canal-building.
In modern civil engineering projects, detailed study and analysis of open channel flow is commonly required to support flood control, irrigation systems, and large water supply systems when an aqueduct rather than a pipeline is the preferred solution. The aqueduct is a simple way to get water to other ends of a field.
In the past, aqueducts often had channels made of dirt or other porous materials. Significant amounts of water are lost through such unlined aqueducts. As water gets increasingly scarce, these canals are being lined with concrete, polymers or impermeable soil. In some cases, a new aqueduct is built alongside the old one because it cannot be shut down during construction.
Modern water supply systems get water from a variety of locations, including aquifers, lakes, rivers, wells, desalinated seawater, and other sources. The water is then purified.
The intake from these water sources usually is through a large cage-like box designed to screen out large particulate matter before it enters the system. After it is sucked in by a pumping station or allowed in by a gravity-feed system, it is usually filtered further, chlorinated, fluoridated, and then pumped either to holding locations like water towers or reservoirs, or fed directly into the user's spigot.
Municipalities typically run water supply systems, although sometimes this is the job of a regional supplier that has an independent governmental structure and taxing authority. Reliance on a single public provider or publicly-regulated provider reflects the fact that water supply is a natural monopoly.
Once water is used, it has to go somewhere. Typically wastewater is piped away in a sewer system, which is again almost always a service provided by the same authority as the water supply, since usage of one system implies usage of the other.
Sometimes, due to contamination by pathogens which exceeds a municipality's ability to filter and purify its water supply, a boil water advisory may be invoked, however even this may not be enough. Boiling water may kill pathogens but not the poisons, chemicals and toxins that can enter water supplies after the supplier's treatment process. Reverse Osmosis allows only individual water and mineral molecules to pass into the end-users water taps. Economical systems are now available from suppliers such as Life Solutions in Hong Kong that provide water as pure as mountain streams, purer if truth be told.
More information about Reverse Osmosis can be found on the Life Solutions website.
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