Watershed Basics

• Overview
• What is a watershed?
• Mapping your watershed
• Riparian buffers
• Water cycle
• Drinking water
• Groundwater
• Fluvial geomorphology
• Stewardship
• Land use
• Watershed Evolution
• Water quality

Getting organized

• The "watershed approach"
• Organizing a watershed partnership

Drinking water

Where is it found?

Most drinking water comes from either surface water or groundwater.  Surface water is found in rivers, lakes and reservoirs while ground water occupies aquifers (underground rivers).  Springs are another source of drinking water, though these begin and run underground for a time before surfacing.

Treatment

There are many ways to treat water to make it suitable for drinking.  Exactly how your water source is treated is determined by your supplier.  Often chemicals such as chlorine or fluoride are added in an effect to kill any pathogens (germs) that may be in the water.  Special treatment might also be required to remove any toxic chemicals present in the water.

Use Issues

One of the most critical issues facing society to day is water use.  Though it may seem so, there is not a limitless supply of drinkable water on the earth.  Less than 1% of all of the water on the surface of the earth is suitable for consumption.  Much of the remainder is found in the oceans and polar ice caps.  As droughts occur in localized regions, water use restrictions are drawn up and enforced.  Unfortunately, as the population increases, so do the demands on our water supplies.  Some cities depend on ground water, though most draw upon nearby reservoirs and rivers.  The increasing demand for water is creating a problem as more cities and municipalities wish to tap into over used waterways or begin diverting from streams and rivers used for recreation and wildlife habitat.

The amount of drinkable water in the world is very small when considered against the total amount of water.  Many people think that the supply of pure drinkable water is endless, but it isn't.  The water cycle constantly recharges and refills our water sources, but we must also do our best to preserve these sources.  How we in Pennsylvania treat our waterways and water sources can affect people as far away as Louisiana (most of our waterways drain into the Mississippi river). 

The table below gives a description of the division of Earth's water resources.

By following this table, over 99% of the water on earth is in undrinkable form, just in the ocean and ice. 

For more information and answers to some common questions about drinking water see  "Plain Talk About Drinking Water" by Dr. James M. Symons.