3.3.1 - The Hydrosphere (KQ3): Local/Regional Water Supply Management

Water Disparities and Disagreements

So far, we've looked at a most world/country view of water supply issues.  As in everything we will deal with, regional and local municipalities deal with the direct distribution and storage to the actual people.  While countries may fight over who owns or has access to water bodies, this comes into play between cities, towns, and states as well. We will be doing a case study project to look at different examples of these disparities, but it's not as easy as 'who has the water, gets it.'  Rivers may run through multiple areas, and if areas upstream draw too much water, the areas downstream will lack.  Also, an area upstream may decide to dam a river, drastically reducing the flow downstream.  As we will see in the case studies, this has happened locally between Florida, Georgia, and Alabama, and between countries along the Nile.  Who has rights to what water is a huge political issue, and when between countries, has even been a factor in war.

Local Water Distribution

Once a municipality knows the demand for water and the size and location of their supply, they need to figure out how to distribute it.  The United States and the States themselves have regulations on the cleanliness of the water distributed to people.  Whether it needs to be pumped from an aquifer, like Florida, Australia, etc.) or taken from a river or lake, the municipalities have jobs to make sure it is clean for consumption and that it does not overdraw the source.  If there is overdraw or a drought, they will have to place regulations on how much water can be used and when, such as different watering days for lawns and cars, and penalties for those who exceed the limit.  They then may have to pay other cities for connection to their systems, provided there is enough to distribute.

 Most cities will have holding reservoirs that house large amounts of treated water in storage to be distributed to the citizens.  Water treatment facilities will pump the freshwater from under or above ground, settle out any solids in large tanks called clarifiers and then contact with chlorine to disinfect.  Other treatments may be required depending on the initial quality of the water.  Water may be pumped into water towers above the ground, which act as emergency stores/pressure if systems go down or during peak times.  Most of the water pressure in paper is currently supplied by pumps run at water treatment facilities and along water main lines.  Below is a diagram of a specific treatment and distribution scenario.  A little more detail than we need, but it shows you what happens from source to tap.