6th Grade
The Ups and Downs of Your Watershed
The student will be able to determine that fresh water is a limited resource, which is managed through the use of reservoirs.
* The student will determine the percent of water present on
Earth and the percent of water, which is available for use by
plants and living organisms.
* The student will define a reservoir and other points where
water is collected such as aquifers and wetlands.
* The student will discuss ways in which water is managed and
the importance of reservoir management.
* The student will graph their watershed using a map.
* The student will discuss water ownership and cost of water
usage.
Water is a perpetual resource, which constantly cycles in our environment. The water we use today is the same water, which has been used for thousands of years and hundreds of generations. Due to this cycle students as well as adults often believe that the supply of water is unlimited. This is true to the extent that water is continuously present and always will be. However, the amount of water which is usable for drinking, household use and irrigation, is limited.
The Earth is covered with water, 97 percent of which is salt water. Only three percent of the water is available as freshwater and with two percent tied up in glaciers and polar ice caps that leaves only one percent in lakes, rivers, streams or groundwater.
Water evaporates into the atmosphere and is deposited back on the Earth through the hydrologic cycle. Some of this water is deposited in rivers and streams and still more is absorbed into the ground as groundwater. As water runs, underground or downstream, it is deposited in lakes, wetlands, aquifers and oceans.
Reservoirs, usually an artificial lake used to collect and store water, are filled by rain and rivers or streams that flow into them. Wetlands are the areas between dry land and water. Usually low-lying areas of land that are wet during extended periods of time. These areas occur naturally and have been significantly shaped by the presence of water over time.
Left alone these areas often serve to clean and purify many contaminants from the fresh water.
Aquifers begin below the land surface where the water collects in large quantities. Aquifers sometimes provide water to lakes and reservoirs.
All water sources and the land that supplies them are part of a watershed. A watershed is the land area from which water drains into lakes, rivers, streams and reservoirs. Each local watershed is part of a larger watershed which is a part of the global watershed. The activities that we do as well as the components within such as the soil type affect our local watershed.
7th Grade
Water Use and Abuse
The student will be able to determine the quantity of water by individual, family and city. The student will be able to determine where their water comes from and the quantity of water used by individuals, families and cities.
*The student will determine the amount of water he/she uses daily.
*The student will calculate the amount of water he/she uses weekly and monthly.
*The student will determine the amount of water used in their household monthly.
*The student will determine the amount of water used in their city monthly.
*The student will identify ways to conserve water.
We live on a planet that is primarily made of water. Approximately seventy-five percent of the Earth is covered in water, most of which is in the ocean. Ocean water contains too much salt for people to use for drinking, cooking, cleaning or bathing. This water is also too salty for agricultural or ranching purposes. Approximately ninety-seven percent of all water on Earth is salt water. Three percent of the Earth’s water is fresh water; however, two percent of that is frozen in glaciers and ice caps. That leaves only one percent of all water available for use by an ever-growing population.
Sources of fresh water include rivers, streams, aquifers, reservoirs, groundwater and water in the atmosphere. An unknown quantity of water travels through the air and beneath the Earth’s surface as part of the hydrologic cycle. The known sources are spread out across the Earth unevenly.
Due to the distribution of this valuable resource, water rights have continued to be a political and social issue. As new cities develop and grow, water needs are constantly being evaluated. These decisions include where the water is obtained and how to pay for it.
The reservoirs that serve the Dallas area are Lake Ray Hubbard, Lake Lewisville, Lake Grapevine, Lake Ray Roberts and Lake Tawakoni. We also have plans to use Lake Fork and Lake Palestine in the future when water demands increase. Dallas has water rights from these lakes to obtain 376.9 million gallons per day to serve its residents (as of December 2006).
This water needs to be managed. To learn more about how the city of Dallas manages their water go to http://dallascityhall.com/dwu/water_quality_information.html .
Throughout history people of all nations have settled around water sources. As populations increase the need to transfer water also increases. Dams, wells and reservoirs have allowed development in areas where water is not readily available. Countries, states and even cities that share boundaries often share water resources. As populations in these areas grow the demand for fresh water increases. Fresh water quantities remain relatively constant; therefore, the need for conservation and management of this resource becomes essential.
Conservation is the act of keeping, protecting, or preserving our natural resources. Examples of conserving water are: using low flow shower heads, turning off water while brushing teeth or soaping hands, adding an object to the toilet tank to displace water and collecting water, which normally goes down the drain, while you wait for the water to warm. Naturescaping or xeroscaping land areas, as well as watering in the morning are also helpful ways to conserve water.
8th Grade
Water Quantity
Water to Supply an Ever-Growing Population
The student will begin to understand that although water cycles through our environment, the amount of available fresh water is limited. The student will begin to understand the need for alternative solutions for future fresh water supplies.
- The students will recognize that water is an essential
element of the natural environment.
- The students will model the hydrologic cycle.
- The students will evaluate the changes in population over time and evaluate the present and future demands for fresh water.
- The students will research and identify known ways to conserve fresh water.
- The students will investigate the control and distribution of fresh water locally and globally.
- The students will devise alternative solutions for conserving fresh water for the growing population.
The United States abundance of water leads many people to believe that there will never be a shortage of water. Water constantly cycles through the environment; however, water does not fall evenly on the Earth. Water is carried by trade winds and weather patterns to different parts of the world, and only a small portion of water falls down into our freshwater supplies. Most of the water returns to the oceans. While the United States has an abundance of fresh water with its rivers, lakes, aquifers, and streams, other countries and continents struggle for survival due to their limited supply. As water knows no boundaries, many states and countries share water resources and that creates a need for cooperation and planning.
Due to the natural cycle of water, it is impossible to calculate an exact volume of total water that exists in the world. The world’s water is found in the oceans, lakes, rivers and streams, as well as glaciers, groundwater and the atmosphere. The volume of the Earth’s water can be estimated by utilizing known resources and unknown or inferred resources. Many of our estimates of unknown resources are made through indirect evidence and therefore are uncertain.
An inventory of this valuable resource we need to live, grow food and raise animals leads us to believe that three-fourths of the world is made of water. This number is misleading as 97 percent of that water is in the oceans, full of salt and unusable for our needs. Another two percent is tied up in glaciers or in the atmosphere, leaving less than one percent as available fresh water. This fact makes water a concern for all. Understanding the limited amount of fresh water that is available, conserving this valuable resource and cooperating with other nations will help us to develop and make wise choices about our resources.
Although each person needs only one gallon of water a day to sustain life per person, the average United States household uses 150 gallons. This is more than most other nations around the world. However, freshwater sources are becoming scarce for many countries, especially those experiencing high population growths.
Furthermore, the amount of water on Earth has remained approximately the same since the beginning of time. However, the number of people using this water has grown considerably. As we continue to use this limited, valuable resource some of the water becomes unusable and therefore further limits the supply. The future of our available freshwater may depend on innovative and currently unknown solutions.
Usually low-lying areas of land that are wet during extended periods of time. These areas occur naturally and have been significantly shaped by the presence of water over time.
Due to the natural cycle of water, it is impossible to calculate an exact volume of total water that exists in the world. The world’s water is found in the oceans, lakes, rivers and streams, as well as glaciers, groundwater and the atmosphere. The volume of the Earth’s water can be estimated by utilizing known resources and unknown or inferred resources. Many of our estimates of unknown resources are made through indirect evidence and therefore are uncertain.
An inventory of this valuable resource we need to live, grow food and raise animals leads us to believe that three-fourths of the world is made of water. This number is misleading as 97 percent of that water is in the oceans, full of salt and unusable for our needs. Another two percent is tied up in glaciers or in the atmosphere, leaving less than one percent as available fresh water. This fact makes water a concern for all. Understanding the limited amount of fresh water that is available, conserving this valuable resource and cooperating with other nations will help us to develop and make wise choices about our resources.
Although each person needs only one gallon of water a day to sustain life per person, the average United States household uses 150 gallons. This is more than most other nations around the world. However, freshwater sources are becoming scarce for many countries, especially those experiencing high population growths.
Furthermore, the amount of water on Earth has remained approximately the same since the beginning of time. However, the number of people using this water has grown considerably. As we continue to use this limited, valuable resource some of the water becomes unusable and therefore further limits the supply. The future of our available freshwater may depend on innovative and currently unknown solutions.
