Investigating Water Usage

Investigating Water Usage

Investigating water usage is important not only on a local level, but also on a national one. In some states like California, for example, water is purchased from other states in order to meet the demand of its citizens. Proper water usage and conservation is important to farmers, businesses, and even everyday people. In this report, there are a number of questions that our group needed to address. The first asked is how much in-house water (water from faucets excluding water used for showering, washing dishes, and bathing) does the average American use daily? Second, what is the amount of water an average American uses yearly? And finally, (for a type of visual representation) how big of a container would someone need to fit all of this water?

In addition, to these questions about in-house water usage, we were asked to see how much water was used for lawns in Utah per year and the actual amount of water these lawns need. In essence, are we over-watering and if not, should we find a more water-friendly lawn to use in our yards and parks? For the purpose of this essay, the topics will be broken up into two sections. First, we'll look at in-house water use, and second, the amount of water used for lawns.

In-House Water Use

In group discussion we took two projections. First, we took the figure given by the question that in 1990 the U.S. Geological Survey estimated that as a whole, the U.S. uses 340 billion gallons of water for all domestic, agricultural, industrial, and energy use. The second set of data was found in the textbook which says that "the 2000 census found a U.S. population of about 281 million people" (Using and Understanding Mathematics, 559). One problem arises when using this data, that of the two dates involved. The population of the U.S. in 1990 would be different than that in 2000. In all likelihood, the water usage of 1990 and 2000 would not be the same.

We decided that these numbers, however, would serve the broad and general purposes of this report. The first problem posed is that we must ascertain the amount of water from faucets used for purposes other than washing dishes, bathing, or showering. In order to achieve this number, we took the total amount of gallons used in the U.S. daily and multiplied it by 14.3% (or the US Geological Survey statistic given in the problem), the number of total in house water used by a person daily, except in the areas listed. This problem was worked out as follows:

340 billion gallons of total daily water used X 0.143 (% of total in house water) =

4.556 billion gallons total in house water used daily

In order to find the total amount of in-house water used per person daily one must take the 4.556 Billion gallons of total in house water and divide it by the amount of people in the U.S., which in turn gives us this equation:

4.556 billion gallons/281 million people living in the U.S. ≈

16.21 Gallons in house water used per person daily

For the second phase of our question, we needed to estimate the average number of gallons of in-house water a person uses each year in the U.S. To achieve this we must take the total number of in house water used per person daily and multiplied it by the amount of days in a year, 365 (leap year was taken out of the equation to achieve relative ease of computation). The results are as follows:

16.21 gallons per person daily X 365 days per year ≈

5,917.94 gallons per person per year

The question continues by asking for the dimensions of a square floor of a 13 foot high room filled with water. This means that we must determine the volume of the room by the equation length X width X height. Since the height of this room is given as 13 feet high, the length and width need to be found. In order to do this we must convert the gallons needed to fill the room into inches which is achieved by the following conversions. First, since one gallon of water is the same as four quarts we take the total amount of gallons X 4 as shown here:

5917.94 gallons X 4 =

23,671.74 quarts

Second, we take the number of quarts and convert them into inches. Since one quart equals 57.75 cubic inches of liquid, we take the amount of quarts and multiply by 57.75 to get cubic inches of water as shown with the equation:

23,671.74 quarts X 57.75 =

1,367,043.20 cubic inches of water

Now, we must divide the cubic inches by the amount of inches per cubic foot (or 12 X 12 X 12) to get the total volume of the room:

1,367,043.20 cubic inches of water / 1728 ≈

791.11 cubic feet (total volume of the room)

Finally we use the equation given above (l X w X h) to achieve our final numbers. Since two sides of a square are equal lengths, then length and width must be the same number, as seen here (with x as the length and width):

xÐ'І X 13 feet = 791.11 cubic feet

Divide both sides by 13 =

60.85461538, take square root of both sides to get the final numbers, or

√xÐ'І = √60.85461538, which means x = 7.800936827 feet

This final number demonstrates that the dimensions of the room are 7.800936827 x 7.800936827 x 13 feet. This can be checked by multiplication to find the size of the room.

Water Used for Lawns

The data below shows the Salt Lake City Corporation water use records for one year for an average family in Salt Lake City. The SLC Corporation uses one unit to represent 100 cubic feet of water. As you can see the number of units used increases during the warmer months (see table 1). These numbers are a percentage of this family's water use that goes towards watering the lawn. This family's lawn in 3200 square feet of Kentucky Bluegrass which requires about 30 cubic inches of water per year. We were asked to find the absolute and relative terms of the amount of water used. In addition, we were asked to compare the amount of water required for this lawn, and the actual amount used by this family per year.