Water Underground and Using Freshwater Resources JANUARY 22ND, 2015 PGS

How Water Moves Underground  Like the water in rivers, lakes and glaciers, underground water comes from precipitation.  Water underground trickles down between particles of soil and through cracks and spaces in layers of rock.  Different types of rock and soil have different sized space, or pores, between their particles. The size of the pores determines how easily water moves through rock and soil.

 If the pores are connected in the rocks and soil, both affect water movement. Because they have large and connected pores, materials such as such as sand and gravel allow water to pass through, or permeate. They are known as permeable.  As water soaks down through permeable rock and soil, it eventually reaches layers of materials that it cannot pass through. These materials have few or no pores or cracks. Two examples are clay and granite; they are impermeable, meaning that water cannot pass through easily.

Water Zones  Once water reaches an impermeable layer, it is trapped. It can´t soak any deeper. Instead, the water begins to fill up to spaces above the impermeable material. The area of permeable rock or soil that is totally filled, or saturated, with water is called the saturated zone.  The top of the saturated zone is the water table.  The layer of rocks and soil above the water table is called the unsaturated zone.

Bringing Up Groundwater  Aquifers: any underground layer of rock or sediment that holds water.  Wells: People can obtain groundwater from an aquifer by drilling a well below the water table.  Using pumps

Using Freshwater Resources  People use water for household purposes, industry, transportation, agriculture, and recreation.

Conserving Water  Conservation: is the practice of using less of a resource so that it will not be used up.  Reducing water use, recycling water, and reusing water are three ways to conserve water.

What is Pollution?  Water pollution: is the addition of any substance that has a negative effort on wáter or the living things that depend on the water. The substances that cause water pollution are called pollutants.  Scientists classify sources of pollution, in part, by how they enter a body of water.  Point source: a specific source of pollution that can be identified.  Nonpoint source: a widely spread source of pollution that can´t be tied to a specific point of origin.

Water to Drink  Color and odor are factors that affect water quality.  Water Quality: is a measurement of the substances in water besides water molecules.  Certain substances such as iron, can affect the taste or color of water but are harmless unless present at very high levels. Other substances, such as certain chemicals and microorganisms, can be harmful to your health.  Concentration: is the amount of one substance in a certain volumen of another substance.

Factors that affect Water Quality  Acidity: the pH of water is a measurement of how acidic or basic the water is.  Hardness: the combined level of two minerals calcium and magnesium in a sample of water is referred to as the hardness of that sample.  Diseases-Causing Organisms: such organisms can be detected by a coliforn count, which measures the number of Escherichia coli bacteria. Coliforn bacteria are found in human and animal wastes.

Treating Drinking Water  Water from both public and private supplies often needs some treatment to ensure that it is clean and safe to drink. 