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Water Use


What is this?

Water usage is reported by the United States Geological Survey (USGS) every five years and measured in millions of gallons a day. The region’s water use can be divided into six categories (1):
  1. Public Supply- water withdrawn by public and private water suppliers that furnish water to at least 25 people or have a minimum of 15 connections. This supply of water can be used for domestic, commercial, industrial, or thermoelectric-power purposes.
  2. Domestic- water used for indoor and outdoor household purposes, including drinking water, water for washing clothes or dishes, and watering the lawn. For the purposes of reports prepared by the U.S. Geological Survey, domestic use only includes self-supplied domestic freshwater withdrawals.
  3. Industrial- water used for fabricating, processing, washing, diluting, cooling, or transporting a product; incorporating water into a product; or for sanitation needs within the manufacturing facility. U.S. Geological Survey reports include only the self-supplied industrial withdrawals.
  4. Irrigation- water that is applied by an irrigation system to sustain plant growth in all agricultural and horticultural practices. This also includes the irrigation of golf courses, parks, nurseries, turf farms, cemeteries, and other self-supplied landscape watering uses.
  5. Livestock- water used in livestock watering, feedlots, dairy operations, and other on-farm needs such as cooling facilities, sanitation, and animal waste disposal. It does not include domestic use and lawn or garden irrigation.
  6. Thermoelectric- water used in generating electricity using steam-driven turbine generators including self-supplied freshwater or saline water.

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Photo Sources (left to right):
http://img.groundspeak.com/waymarking/display/0da77a61-ee16-4269-9449-70b7d100faad.JPG
http://www.fws.gov/pacific/ecoservices/envicon/pim/CoreIssues/Images/irrigation.jpg
http://media.photobucket.com/image/durham%20water%20tower/sixtyftsixin/Durham/100_1315.jpg

Why is this important?

It is important to track water use trends in order to determine if the region's population growth can be sustainably supported in terms of drinking water, water for electricity generation, as well as agriculture and industrial production.

How Can I Conserve Water?

  1. Water your lawn only when it needs it.
  2. Fix leaky faucets and plumbing joints.
  3. Don’t run the hose while washing your car.
  4. Install water-saving shower heads or flow restrictors.
  5. Run only full loads in the washing machine and dishwasher.
  6. Shorten your showers.
  7. Use a broom instead of a hose to clean driveways and sidewalks.
  8. Don’t use your toilet as an ashtray or wastebasket.
  9. Capture tap water.
  10. Don’t water the sidewalks, driveway, or gutter.

By following all of these simple instructions you could save 5,750-7,600 gallons of water per month!


What does this measure show?

The region’s demand for water has varied greatly between 1985 and 2005 with the largest quantities of water being used for thermoelectric power generation. Other trends include a steady increase on the amount of water being provided by public suppliers (doubling from 1985 to 2005) and a steady decrease in water being used in irrigation and livestock production (since 2000), which is indicative of the urbanizing nature of the Triangle region. A series of plant foreclosures in between 1995 and 2000 is also indicated by the sharp decrease in industrial water use over that time period.

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Figure 1. Regional use of publicly supplied water in millions of gallons a day
Source: United States Geological Survey
Figure 2. Regional thermoelectric use of water in millions of gallons a day
Source: United States Geological Survey

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Figure 3. Less extensive regional water uses in millions of gallons a day
Source: United States Geological Survey


Table 1. Regional water use by category from 1985-2005, measured in millions of gallons a day (listed from highest use to lowest use in 2005)
Source: United States Geological Survey
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Limitations and Further Research

The greatest limitations with the data reported by the U.S. Geological Survey is a lack of consistency in the definition of the different water usage categories and that the data is only collected every 5 years. Due to the definitions of public supply and domestic use it is also difficult to determine how much water is actually used for domestic (such as drinking water), industrial, irrigation, livestock, or thermoelectric uses. Data is also limited to the amount and accuracy of information voluntarily supplied by users. Local Water Supply Plans were also used for the average daily demand findings which were prepared during different years and therefore had data from different years for each municipality making an overall estimation of the regional demand for any given year difficult.


Author Katherine Hebert, UNC Chapel Hill :: 2010 April 26
Reviewers
Tom Davis, Water Resources Coordinator, Orange County's Environment and Resource Conservation Department
Amy Pickle, Senior Attorney for State Policy, Nicholas Institute for Environmental Policy Solutions, Duke University



Technical Notes

1. The source for water use category definitions was the U.S. Geological Survey Water Use in the United States Report at http://water.usgs.gov/watuse/.
2. The source for suggestions on how to conserve water was provided by the Mono Lake Committee at http://www.monolake.org/about/waterconservation. This is not an exhaustive list but a rather inclusive list of simple measures people can take to conserve water and included an estimate of water conserved through each measure which was desired. There are many other measures for conserving water which can be found by searching the internet.
3. The regional water use table and accompanying graphs were created by summing the water use in millions of gallons a day for the six counties (Wake, Orange, Lee, Johnston, Chatham, and Durham) in each water use category for each year. The sums were then organized in the table in descending order by the amount of water used in 2005. The source of this data was the U.S. Geological Survey Water Use Data by State published every five years from 1985 to 2005.Categorical Water Usage.xlsx


Water Indicators
Fresh Water Supply :: Water Use
Water Pollution :: Miles of Impaired Streams :: Riparian Buffers :: Major Dischargers :: Groundwater
Case Studies :: Jordan Lake Rules :: Falls Lake Rules