Hydrology is the scientific study of the movement, distribution and management of water on Earth and other planets, including the water cycle, water resources and watersheddrainage basin area contributing water to a network of stream channels, a lake or other areas where water can collect sustainability.[1]

Official chemical name for water?
Water is one of our most important natural resources. Without water there would be no life on Earth. But Earth's water supply is limited and isn't always where humans and other living organisms need it.

Chemical wastes improperly discarded in the past are appearing in today's water supplies, but hydrology knowledge and application help scientists and the public respond to changes in complex water systems and solve water-related problems. Hydrologists play a vital role in finding those solutions.[1]

Branches of hydrology include: hydrogeology,geology that deals with the distribution and movement of groundwater in the soil and rocks of the Earth's crust hydrogeology, chemical hydrology, ecohydrology,the study of the interactions between water and ecological systems hydroinformatics,application of information and communications technologies to address problems in the equitable and efficient use of water for many different purposes isotopeone of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical behaviour but with different atomic masses and physical properties hydrology, surface hydrology, hydrometeorology,the study of the transfer of water and energy between the land surface and the lower atmosphere drainage basinan area of land where precipitation collects and drains into a common outlet, such as a river, bay or other body of water management and water quality.[2]


Greeks considered water one of four elements along with what other elements?
[1] USGS. (n. d.). What is hydrology? https://www.usgs.gov/special-topic/water-science-school/science/

[2] Journal of Hydrogeology & Hydrologic Engineering. (2018). Surface hydrology. https://www.scitechnol.com/hydrology/surface-hydrology.php#:~:text=The%20branches%20of%20Hydrology%20include,is%20a%20branch%20of%20Hydrology.

Water Properties

Water phase diagram
D. Kinkoph
May 26, 2011
Embedded video, no copy made
Water has several interesting and unique properties:

Water consists of two hydrogen atoms bonded to one oxygen atom, H2O. Its formal names are oxidane and dihydrogen monoxide. Water is a polar molecule because the hydrogen side of the water molecule has a positive charge and the oxygen side has a negative charge.[1]

Universal solvent:
Because of its molecular structure, water can dissolve a large number of different chemical compounds. Water can carry solvent nutrients in runoff, infiltration and groundwater and can transport living organisms.[1]

High surface tension:
Its molecular bonding makes it adhesive and elastic.relating to a substance that can quickly return to its normal shape after being pulled or pushed It forms drops rather than spreading out over a surface. Water tends to stick to the sides of vertical structures despite gravity's downward pull. Its high surface tensionwhen the surface of a liquid resists breaking by objects placed on it also allows waves to form and enables plants to move water from their roots to their leaves.[1]

Water's atomic structure provides unique electrochemicalscientific study of the electrical aspects of chemical reactions properties. Because it is a polar molecule,a molecule in which one end of the molecule is slightly positive, while the other end is slightly negative its bonds are strong.[1]

Conductivity:refers to how a material conducts electricity
Water conducts heat more easily than any liquid except mercury,a silver-white poisonous heavy metallic element that is liquid at ordinary temperatures used in batteries, in dental amalgam, and in scientific instruments which causes large bodies of liquid water like lakes and oceans to have a fairly uniform vertical temperature profile.[1]

Solids, Liquids and Gases of Water Molecules
Royal Society of Chemistry
Sep. 24, 2014
Embedded video, no copy made
High specific heat:
Because water has a high
specific heatthe amount of energy required to change the temperature of a substance
it can absorb large amounts of heat energy before it begins to get hot. It also means that water releases heat energy slowly when situations cause it to cool. Water's high specific heat moderates Earth's climate and helps organisms regulate their body temperatures.[1]

Neutral pH:
In a pure state water has a neutral pHscale used to specify how acidic or alkaline a water-based solution is, acidic solutions have lower pH, and alkaline solutions have higher pH of about 7 so it is neither acidic nor alkaline. Water changes its pH when substances are dissolved in it. Water is amphoteric.refers to a substance able to react both as a base and as an acid, such as water[2] Rain has a naturally acidic pH of about 5.6 because it contains natural carbon dioxide and sulfur dioxide.[1]

Water molecules are the only substance on Earth that exist naturally in all three physical states, solid, liquid and gas. Incorporated in the changes of state are massive amounts of heat exchange which play an important role in heat redistribution in Earth's atmosphere. Approximately 3/4ths of this process is accomplished by water evaporationprocess of turning from liquid into vapor and condensation.conversion of a vapor or gas to a liquid[1]

Water molecules exist in liquid form over an important range of temperature from 0oC (32oF) to 100oC (212oF). This range allows water molecules to exist as a liquid in most places on our planet.[1]

Adding salt to water increases its conductivity, raises its boiling point and lowers both its melting point and specific heat.
Water salinity
Water salinity
P. Summerlin
Feb. 9, 2011
Wikipedia water salinity
CC BY-SA 3.0
Water Salinity[3]
classification salinity in pptparts per trillion location
fresh water 0 - 0.5 ponds, lakes, rivers,
streams, aquifers
brackish water 0.5 - 30 estuaries,
mangrove swamps
saline water 50+ seawater,
salt lakes
briny water 10,000 ppm to 35,000 ppm brine ponds

Water is the major constituent of almost all life forms. Most animals and plants contain more than 60% water by volume. Without water life would probably never have developed on our planet.[1]

Unlike most substances, freezing water molecules causes their mass to occupy a larger volume. When water freezes it expands rapidly, adding about 9% by volume. Fresh water has a maximum density at around 4oC. Water is the only substance on this planet where the maximum density of its mass does not occur when it becomes a solid.[1] As it freezes, its density decreases, which explains why ice floats.


[1] PhysicalGeography.net. (n. d.). Physical properties of water. http://www.physicalgeography.net/fundamentals/8a.html

[2] Mutsoll, V. (Jan. 4, 2021). 10 important properties everyone should know about. https://www.legit.ng/1394221-10-important-properties-water-about.html

[3] USGS. (Jun. 11, 2018). Saline water and salinity. https://www.usgs.gov/special-topics/water-science-school/science/saline-water-and-salinity

Hydro Power and Dams

The statue of Ramses the Great at the Great Temple of Abu Simbel is reassembled after having been moved in 1967 to save it from flooding
The statue of Ramses the Great at
the Great Temple of Abu Simbel is
reassembled after having been moved
in 1967 to save it from flooding
P. Anderson
Jan. 1, 1967
Wikipedia Abu Simbel
public domain
Water has been used for thousands of years. Ancient Romans built turbines, wheels turned by flowing water, to grind grains.[1]

The first U.S. hydroelectric powerthe amount of energy transferred or converted per unit time plant was built on the Fox River in 1882 in Appleton, Wisconsin. It powered two paper mills and one home.[1]

Water mills, used before the Industrial Revolution, are large wheels on flowing river banks that generated energy for grain grinding, timber cutting and fires for steel production.[1]

Hydroelectricity, used today, is a clean, renewable energy source, produced by moving water. It improves hygiene and education and provides community employment opportunities.[1]

Billions of people depend on it, and it is often one of the first energy sources used by developing countries to provide energy to rural areas. As their populations have increased China and India built dozens of dams to produced energy.[1]

Egypt began construction of the Aswan Dam power plant Aswan Dam power plant Aswan Dam power plant
Feb. 28, 2012
Wikipedia Aswan dam
CC BY-SA 3.0
complex on the Nile River in 1960. Engineers realized that ancient cliff temples of Abu Simbel were going to be flooded by the Lake Nasser reservoir. To save the cultural relics, the Egyptian government moved the entire mountainside to artificial hills above the dam.[1]

The U.S. also depends on hydroelectric energy. During the 1930s Great Depression dams, including the Columbia River Bonneville Dam, Bonneville Dam Bonneville Dam
Jun. 20, 2013
Wikipedia Bonneville dam
CC BY-SA 3.0
the Sacramento River Shasta Dam, Shasta Dam Shasta dam
Bureau of Reclamation
Feb. 12, 2017
Wikipedia Shasta dam
CC BY-SA 2.0
and the Colorado River Hoover Dam, were built as part of the New Deal, a series of government programs that provided jobs.[1]

The most famous hydroelectric New Deal power project was the Tennessee Valley Authority (TVA) which constructed several dams on the Tennessee River and its tributaries. TVA is now the largest public U.S. power company, providing electricity to Alabama, Georgia, Kentucky, Mississippi, North Carolina, Tennessee and Virginia.[1]

One of the most famous hydroelectric plants, the Robert Moses hydroelectric power plant,, Robert Moses hydroelectric power plantRobert Moses
hydroelectric power plant
Apr. 18, 2008
Wikipedia Niagra Falls
CC BY 3.0
borders the U.S. and Ontario, Canada at Niagara Falls. While engineers can't turn the falls off, they can limit the plant's water intake.[1]

To produce hydroelectric power, water needs to be retained in a reservoir usually created by a dammed river or artificial lake. A controlled water flow of millions of gallons is channeled through dam tunnels to rotate turbines that move generators.[1]

Hydroelectricity sometimes has a human cost, requiring residents to permanently relocate before dam construction begins. And these structures may prevent fish from swimming upstream. The Bonneville Dam installed fish ladders, wide steps built on the side of the river and dam, to enable fish to slowly swim upstream.[1]

Aquatic birds and plants are sometimes at risk when dams flood river banks, destroying wetland habitat for thousands of organisms. Hydroelectric plants may change reservoir water temperatures, forcing animal migrations.[1]

Hydropower plant energy is measured in gigawatt hours (GWh),a unit of energy equal to billion watt hours terawatt hours (TWh),a unit of energy equal to one trillion watt hours and petajoules (PJ)a unit of energy equal to one million billion joules.

10 Largest Hydroelectric Power Plants[2]
dam river location annual power generation construction
information image
Three Gorges Yangtze River Yichang, Hubei province, China 101.6 terawatt hours/
366 petajoules
  • world's biggest hydropower station
  • 181 meter tall and 2,335 meter-long gravity dam
  • 32 turbine generator units rated 700 megawatts each and two 50 megawatt power generators
  • Three Gorges hydropower plant and dam
    Three Gorges hydropower plant and dam
    Sep. 20, 2009
    Wikipedia Three Gorges dam
    CC BY-SA 2.0
    Itaipu Parana River Brazil and Paraguay border, Brazil and Paraguay 76.382 terawatt hours/
    274.98 petajoules
  • built by a U.S.-Italy consortium
  • power production began in May, 1984
  • supplied 15% of Brazil's energy consumption and 90% of energy consumed in Paraguay in 2018
  • consists of 20 generating units with a capacity of 700 megawatts each
  • in 2016 it was the world's largest hydropower plant
  • Itaipu hydropower plant and dam
    Itaipu hydropower plant and dam
    J. de Carvalho
    Dec. 31, 2020
    Wikipedia Itaipu dam
    CC BY-SA 3.0
    Xiluodu Jinsha River Sichuan Province, China 55.2 terawatt hours/
    198.72 petajoules
  • world's first ultra-high concrete double-curvature arch dam at an elevation of 610 meters
  • maximum dam height is 285.05 meters
  • power transmitted through the State Grid and China Southern power grid
  • Xiluodu hydropower plant and dam
    Xiluodu hydropower plant and dam
    D. Chenxing
    Jul. 17, 2011
    Wikipedia Xiluodu dam
    CC BY-SA 4.0
    Simón Bolívar Caroni River Bolívar state, Venezuela 47,000 gigawatt hours/
    169.2 petajoules
  • also called the Guri Dam
  • consists of 20 generating units of different capacities ranging between 130 megawatts and 770 megawatts
  • was refurbished in 2007 and 2009
  • Simón Bolívar hydropower plant and dam
    Simón Bolívar hydropower plant and dam
    Wikipedia Guri dam
    public domain
    Belo Monte Xingu River Pará, Brazil 39.5 terawatt hours/
    142.2 petajoules
  • owned and operated by Norte Energia, a consortium led by the Brazilian electric utility company Eletrobas
  • comprises two dams and two powerhouses
  • Belo Monte hydropower plant and dam
    Belo Monte hydropower plant and dam
    Vice-Presidência da República
    Jul. 17, 2011
    Wikipedia Belo Monte dam
    CC BY-SA 2.0
    Tucuruí Tocantins River Tucuruí, Pará, Brazil 21.4 terawatt hours/
    77.04 petajoules
  • concrete gravity dam 78 meters tall and 12,500 meters long
  • consortium of Alstom, GE Hydro, Inepar-Fem, and Odebrecht supplied equipment
  • delivers electricity to the town of Belém and the surrounding area
  • Tucuruí hydropower plant and dam
    Tucuruí hydropower plant and dam
    Sócrates Arantes/Eletronorte - Agência Brasil
    May 1, 2004
    Wikipedia Tucuruí dam
    CC BY-SA 3.0
    Grand Coulee Columbia River Washington, U.S. 20.24 terawatt hours/
    72.86 petajoules
  • owned and operated by the U.S. Bureau of Reclamation
  • consists of three power plants and a concrete gravity dam 168 m tall and 1,592 m long
  • overhaul began in 2013, 2016 and 2019
  • Grand Coulee hydropower plant and dam
    Grand Coulee hydropower plant and dam
    G. M. Erickson
    Sep. 6, 2009
    Wikipedia Grand Coulee dam
    CC BY-SA 3.0
    Xiangjiaba Jinsha River Sichuan, Yibin and Shuifu County, Yunnan, China 30.7 terawatt hours/
    110.52 petajoules
  • dam is 162 meters high with a crest elevation of 384 meters
  • eight units of 800 megawatts each
  • consists of various structures for flood discharge, diversion, power generation and ship lift
  • Xiangjiaba hydropower plant and dam
    Xiangjiaba hydropower plant and dam
    Y. Sun
    red uper
    Image used with permission
    of and provided by Y. Sun
    Sayano-Shushenskaya Yenisei River Sayanogorsk, Khakassia, Russia 23.5 terawatt hours/
    84.6 petajoules
  • arch-gravity dam 242 meters tall and 1,066 meters long was constructed
  • 70% is delivered to four aluminium smelters in Siberia
  • in 2009 the plant was shut down temporarily following an accident, which damaged the turbines
  • it reopened in 2010, after repair
  • ten new units with 96.6% efficiency are planned for installation
  • Xiangjiaba hydropower plant and dam
    Xiangjiaba hydropower plant and dam
    Oct. 12, 2020
    Wikipedia Sayano-Shushenskaya dam
    CC BY-SA 4.0
    Longtan Hongshui River Tian'e County, Guangxi, China 18,700 gigawatt hours/
    67.32 petajoules
  • consists of nine 700 megawatt generating units
  • concrete gravity dam 216.5 meters high and 832 meters wide
  • turbine generators supplied by Voith, Dongfang, Harbin, and Tianjin
  • Longtan hydropower plant and dam
    Longtan hydropower plant and dam
    Y. Sun
    Red uper
    Image used with permission
    of and provided by Y. Sun

    The O'Shaughnessy dam in 1923
    The O'Shaughnessy dam in 1923
    Wikipedia O'Shaughnessy dam
    public domain
    Dams are constructed for four basic purposes:

    There are more than 90,000 large and small dams in the United States.[3]

    Dams have three structural elements:

    During flood conditions, excess water is directed into a spillwaya structure that allows water to flow directly into the river or other body of water below a dam, bypassing all tunnels, turbines, and generators to prevent damage to surrounding lands. Dams can only provide limited energy, determined by hundreds of meters of siltationprocess of blocking something with sand or soil built up on reservoir bottoms.[1]

    The O'Shaughnessy Dam on the Tuolumne River in California drew criticism for its environmental impact. The dam, constructed in 1913, created the Hetch Hetchy reservoir and flooded the Hetch Hetchy Valley, part of Yosemite National Park.[1]

    Environmentalists opposed the dam, but the plant provided affordable hydroelectric energy to San Francisco and the surrounding area. The plant's existence is still controversial, and some environmentalists believe the plant should be destroyed so the valley can return to its original state.[1]

    Greatest Dams in the U.S.[3]
    dam river location feature construction
    information image
    Oroville Feather Oroville region, California tallest 1961-1969
  • constructed by the California Department of Water Resources
  • more than 770 feet high
  • met the need for water for San Joaquin Valley
  • the Edward Hyatt Pump-Generating Plant generates electricity of 28,000-megawatts
  • Oroville dam
    Oroville dam
    State of California
    public domain
    Cochiti Rio Grande Cochiti Pueblo, New Mexico longest 1965-1973
  • 5.5 miles/29,040 feet
  • one of the world's shortest in height
  • has a permanent recreation pool
  • Cochiti dam
    Cochiti dam
    U.S. Army Corps of Engineers
    Jun. 1, 2001
    public domain
    Grand Coulee Columbia Okanogan and Grant Counties of Washington State highest power production 1933-1942
  • primary objective of the dam was to control flooding and meet the need of irrigation
  • later used for power generation of 21 billion kilowatt-hours
  • Grand Coulee dam spillway
    Grand Coulee dam spillway
    U.S. Bureau of Reclamation
    Jan. 1, 1942
    public domain
    Hoover Colorado Clark County of Nevada and Mohave County of Arizona largest water retention 1931-1936
  • 1244 feet long, 726 feet high, wall width 16 feet
  • The wall of the dam encompasses a volume of 3.25 million cubic yards
  • Hoover dam from across the Colorado River
    Hoover dam from across the Colorado River
    A. Adams
    Jan. 1, 1941
    public domain

    [1] National Geographic. (2022). Hydroelectric energy: The power of running water. https://education.nationalgeographic.org/resource/hydroelectric-energy-power-running-water

    Condensed atmospheric water can create?
    [2] Power Technology. (Jul. 27, 2020). The 10 biggest hydroelectric power plants in the world. https://www.power-technology.com/analysis/feature-the-10-biggest-hydroelectric-power-plants-in-the-world/

    [3] CivilEngineeringBible. (n. d.). Greatest dams of United States. https://civilengineeringbible.com/article.php?i=294

    [4] CivilEngineeringBible. (n. d.). Structural elements of a dam. https://civilengineeringbible.com/article.php?i=238

    Phase Changes

    Phase changes
    Phase changes
    Water's Three Physical States
    Healing Earth
    CC0 public domain
    In order for water to change from a solid to liquid and then to a gas, a water molecule must gain energy. The energy absorbed by water is used to break hydrogen bonds among molecules. When the bonds are broken between ice molecules it melts and the molecules can circulate as liquid water.[1]

    The energy required to convert ice into water is called the latent heat of fusion.amount of heat required to convert a specific amount of a substance from a solid to a liquid It takes about 80 calories of heat to convert one gram of ice into water. The energy required to convert water into steam is called the latent heat of vaporization.amount of heat required to convert a specific amount of a substance from a liquid to a gas It takes about 600 calories of heat to convert one gram of water into steam.[1]

    Most of us are familiar with freezing, when liquid water undergoes a phase change and converts to solid ice, and melting, when water also undergoes a phase change from solid ice to liquid water. When heat is added to liquid water it changes to water vapor, dissipating in the atmosphere. When water vapor in the atmosphere cools, it undergoes condendensation.

    The two phases we seldom see in daily life are sublimation,transition of a substance directly from the solid to the gas phase, without passing through the intermediate liquid phase when ice converts directly into water vapor in the atmosphere, and deposition,transition of a substance directly from the gas to the solid phase, without passing through the intermediate liquid phase when water vapor converts directly into solid ice. Sublimation can be observed by blowing across the tops of ice cubes in an ice cube tray.

    There are 19 known forms of ice.[2] Only a few appear in nature, while others can be created in laboratories, found in diamonds or identified on Jupiter's moon Europa. The forms differ in their arrangement of hydrogen atoms.[3]


    [1] Ward, D. (2022). Water in the atmosphere. Atmo 336: Water, climate, and society. University of Arizona. http://www.atmo.arizona.edu/students/courselinks/fall16/atmo336s2/lectures/sec1/water.html

    [2] Santa Maria, C. (Mar. 12, 2021). There are now 19 forms of ice, thanks to this discovery. The Weather Network. https://www.theweathernetwork.com/en/news/nature/habitats/there-are-now-19-forms-of-ice-thanks-to-this-discovery

    [3] Gasser, T.M., Thoeny, A.V., Fortes, A.D. et al. (2021). Structural characterization of ice XIX as the second polymorph related to ice VI. Nature Communications, 12(1128). https://doi.org/10.1038/s41467-021-21161-z

    Hydrologic Cycle

    Water cycle
    Water cycle
    Corson-Dosch, H., et al.
    public domain
    The hydrologic cycle explains water's motion among oceans, continents and atmosphere. Water motion is powered by gravity and the Sun.

    About 97.5% of Earth's water is contained in the oceans, 2.5% in polar ice caps and ground water, and 0.0001% in the atmosphere.[1]

    A water molecule will stay in the ocean for about 3,000 years before it is evaporated and added back into the water cycle. It will remain in the atmosphere for about 10 days before falling as rain, snow or condensation back into the oceans or onto land. Once on land, water can seep into the ground, flow across the surface and enter streams, rivers, or lakes, or become part of a glacier in colder environments.[1]

    Plants use a lot of water and return it to the atmosphere by transpiration.exhalation of water vapor through the stomata of a plant or leaf There is no net water loss in the atmosphere, biosphere, and cryosphere,portions of a planet`s surface where water is solid, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps, ice sheets, and frozen ground but overall global distribution changes due to climatic variations and global warming.[1]


    [1] Milligen, M. (Apr. 1999). Do you have any information on
    the hydrologic cycle specific to Utah? Survey Notes, 31(2). Utah Geolgical Survey. https://geology.utah.gov/map-pub/survey-notes/

    Water Balance

    Water movement
    Water movement
    E. Tal
    Feb. 26, 2016
    Wikipedia water cycle
    public domain
    Water changes state from vapor to liquid to a solid under natural conditions. Within a specific area over a specific period of time water inflows are equal to water outflows, plus or minus any storage changes. This means that water entering an area has to leave or be stored in that the area.[1]

    The simplest form of water balance equation is:

    P = Q + E ± ΔS

    P = precipitation, Q = runoff, E = evaporation and ΔS = storage in soil, aquifers or reservoirs.[1]

    A water balance analysis has two main applications. It can be used to assess current status and trends in water resource availability in an area over a specific period of time, and strengthen water management decision-making, by using data to assess validity of scenarios and strategies.[1]

    Water balance analysis divides water into "green" and "blue" water. "Blue" water, having been used for irrigation, is the surface and groundwater available for irrigation urban and industrial use and environmental flows. "Green" water, from rainfall, is water that has been stored in the soil and that evaporates into the atmosphere.[1]


    [1] Stauffer, B. (n. d.). Water balance estimation. https://sswm.info/sswm-university-course/module-4-sustainable-water-supply/further-resources-water-sources-software/water-balance-estimation

    Water Reuse[*]

    Recycled water
    Recycled water
    Mar. 8 , 2023
    public domain
    Water reclaimation, recycling and reuse have become important parts of some water systems. This includes using desalinationprocess of removing salt from seawater and effluenttreated municipal wastewater treated to acceptable standards for non-potablerefers to water that is not safe to drink and potablerefers to water that is safe to drink uses.[2]

    Recycling municipal water can help meet growing population needs. It is often less expensive than water from other sources and is more readily available. Sometimes the water is stored in basins, creating wetlands that attract and benefit local birds and animals.[26]

    In 1976, California's Orange County Water District began including 15 million gallons per day of highly treated municipal wastewater into its groundwater. In 2008 the system was expanded to 70 million gallons per day. The advanced treatment groundwater replenishment system uses municipal effluent from a nearby wastewater treatment plant, microfiltration,contaminated fluid is passed through a filter to remove microorganisms and suspended particles reverse osmosiswhen a solvent passes through a porous membrane in the direction opposite to that for natural osmosis when subjected to a hydrostatic pressure greater than the osmotic pressure and an advanced oxidation process to further treat the water, which is pumped into recharge basins and injected into wells, mixing with groundwater. The system provides drinking water for more than 2 million people and serves as a model for other potable use projects.[3]

    Indirect potable reuse (IPR)uses an environmental buffer, such as a lake, river or a groundwater aquifer before the water is treated at a drinking water treatment plant releases water from a wastewater treatment plant into an environmental buffer.a groundwater aquifer, surface water reservoir, lake or river in which advanced treated water is introduced before being used for potable reuse The water is mixed with water from other sources and is then removed from the buffer and purified to drinking water standards before delivery to water customers.[5] In the past, IPR has been accepted because the public found it difficult to accept treated reclaimed water directly, called "toilet to tap," from water reclamation facilities even when that water meets EPA drinking water standards.[8]

    IPR can be stored during low demand times for use during high demand periods. Because stored water can become polluted by natural or chemical contaminants IPR often needs to be repurified.[9]

    Drinking water scenario: Indirect potable reuse
    MidCoast Water
    Sep. 27, 2015
    Embedded video, no copy made
    Relocating IPR to an environmental buffer may require significant transportation and removal costs. In Las Vegas treated wastewater effluent flows by gravity to Lake Mead. Before treatment it has to be pumped and returned to the water supply.[9]

    The removal of IPR from a riparianrelating to wetlands adjacent to rivers and streams area can also result in long-term habitat loss and destruction of native species, which are then replaced by invasive, non-native species that resist removal.[9]

    In 2009 San Diego started the Water Purification Demonstration Project to show residents that IPR was safe and that a large-scale project could provide a reliable drinking water supply. The project, renamed Pure Water San Diego, explained to the public why alternative drinking water sources were necessary, demonstrated the water's purity and enlisted the support of academics and medical professionals to work with the media to ensure that water messages were factual and clear. The public can tour the facility to learn about IPR technology and taste purified drinking water.[20]

    Surveys conducted by the San Diego County Water Authority demonstrated a substantial shift in public opinion of IPR between 2004 and 2011. In 2004, 45% of residents opposed using advanced treated recycled water, but by 2011, that number fell to 11%,[4] with many respondents requesting that highly purified water be used directly, rather than being released into the ground or a storage facility before use.[21]

    Hyperion 2035 is led by Los Angeles Sanitation and Environment. The project will upgrade the city's oldest wastewater treatment facility, the Hyperion Reclamation plant, with an advanced purification process enabling it to produce 100% recyclable wastewater by 2035.[28]

    The International Space Station (ISS) has provided a live lab for testing direct potable reuse (DPR)involves the treatment and distribution of water without an environmental buffer that returns purified water directly into a water system after wastes have been removed and the water has been purified through the station's wastewater treatment system. Because each crew member is allocated only two liters of water per day the ISS relies on a 2008 NASA DPR water recovery system that collects humidity and distills about 85% of water in urine. The system uses physical and chemical processes to remove contaminants from wastewater, stores it in a tank for reuse and checks water quality.[4],[5]

    Recycling Water: Direct Potable Reuse Explained
    Colorado School of Mines
    Aug. 6, 2021
    Embedded video, no copy made
    Unlike IPR, DPR doesn't use an environmental buffer[5] and can be placed directly into a drinking water system without additional cleaning, pumping, transmission or water loss.[10]

    There are two applications of DPR. The first uses advanced treated water (ATW) produced in an advanced water treatment facility (AWTF) and adds it to the water upstream of a drinking water treatment facility (DWTF). This option is used in Texas' Colorado River Municipal Water District's Big Spring Raw Water Production facility and the City of Wichita Falls DPR Project.[6]

    The second uses water produced in an AWTF permitted as a drinking water treatment facility (DWTF), adding it directly into a drinking water distribution system. This process is referred to as treated drinking water augmentation. This method is currently used in Windhoek, Namibia.[7]

    There are no federal DPR regulations. California and Texas, however, have been proactive in drafting them.

    The California DPR initiative began in 2012 as a partnership between the WateReuse Research Foundation and WateReuse California.[11] The state established a water recycling goal of 2.5 million acre-feet by 2030, more than four times its current water recycling effort, impossible with only non-potable reuse and IPR.[12]

    California Water Code, Division 7, Chapter 7.3 required adoption of DPR criteria by December 31, 2023.[13] In 2017 the California State Water Board's Division of Drinking Water drafted a single criterion for DPR to streamline system development.[14]

    In 2022 the Texas Water Development Board published Final Report: Direct Potable Reuse Resource Document establishing source control, monitoring framework, water quality goals, treatment and testing strategies, risk assessment strategies, regulatory and legal considerations and public outreach plans for DPR implementation.[6]

    Water recycling for the future of Texas
    T. Nguyen
    Mar. 13, 2018
    Embedded video, no copy made
    The Texas Commission on Environmental Quality (TCEQ) approves DPR projects on a case-by-case basis in accordance with the innovative and alternative treatment clause in the Texas Administrative Code.[6]

    In 1970, Denver built an AWTF pilot plant. For five years, the plant used secondary effluent from the Metropolitan Denver Sewage Disposal plant to demonstrate safety and reliability.[19] Research and design data were collected during the pilot.

    Before the study, a University of Colorado survey showed that only 38% of participants favored DPR, but after public education efforts, another public opinion survey showed that 84% of Denver customers would accept DPR if water quality met or exceeded current drinking standards.[19]

    Formed in 1949, the Colorado River Municipal Water District (CRMWD) supplies water for arid west Texas communities, including Big Spring. Between 1950 and 1990, CRMWD built three dams to create surface water reservoirs storing water from Texas' Colorado River and developed four large groundwater well fields. Although CRMWD's surface water reservoirs have a combined storage capacity of over 1.2 million acre-feet, drought resulted in water levels below intake levels and dry reservoirs.[14]

    Sixty inches of annual evaporation, several decades of drought, an increasing population related to the oil and gas industry, lack of space for an additional reservoir and no suitable aquifers caused CRMWD to reject both IPR and more expensive desalination.[18], [22]

    Construction of the Big Spring reclamation facility began in 2010. As the first DPR facility in the U.S., Big Spring also made national headlines.[22]

    One year later, the indirect potable reuse
    pipeline is effective, officials, citizens say
    Feb. 26, 2019
    Embedded video, no copy made
    By 2013, 2.5 million gallons per day of treated Big Spring effluent was being diverted to an advanced water treatment facility where it was purified using microfiltration, reverse osmosis and advanced oxidation processes. That water was then blended with treated water from the system's three reservoirs, piped into the Big Spring water treatment plant and treated to Safe Drinking Water Act standards.[18]

    In 2012, reservoirs in Wichita Falls, Texas, were at less than 20% capacity and groundwater was unavailable. Water managers recognized that DPR was the only option remaining. The city had already installed an AWTF system to treat a brackish lake for IPR.[22]

    Turning to Big Spring for advice, the city began the 27-month permitting process with TCEQ. Anticipating approval, a 13-mile above-ground pipeline was built to transport effluent from the wastewater treatment plant to 37 the AWTF system at a cost of $13 million. The system came online in July 2014, providing 18.9 million liters of potable water per day, one-third of the city's daily demand.[22]

    The drought ended a year later and the system was converted back to IPR, delivering treated wastewater to Lake Arrowhead.[22]

    The Wichita Falls DPR program encountered almost no opposition because the water utility had an excellent reputation and a 40-year history of operating an IPR.[20] Before the process began, city officials received support from professors, local doctors and the media and held meetings to educate the public about the project.[22]

    Windhoek, Namibia's water supply consists of dams fed by seasonal rivers and borehole water.[15] As the most arid country in sub-Saharan Africa, its water sources rely on infrequent and inconsistent rainfall. The city used up all conventional water supplies within 500 kilometers, considered transporting water from the Okavango River, more than 800 kilometers from the city or using desalinated seawater pumped up 1,700 meters, but those scenarios were too expensive.[16]

    Windhoek in Namibia is been producing
    potable wastewater for 50 years
    Le Monde Afrique
    Dec. 15, 2021
    Embedded video, no copy made
    The city has been treating wastewater for more than 45 years. The country has no wastewater guidelines, so the city established its own. Between 1964 and 1968, the Windhoek City Council, National Institute for Water Research, and Council for Scientific and Industrial Research performed a DPR pilot study. The Goreangab Water Reclamation Plant began producing high-quality effluent for DPR using only domestic sewage as the world's first DPR project.[17],[18]

    The fully automated plant, run by three trained operators per shift, continuously monitors water purity. The plant is producing 21,000 cubic meters (5.5 million gallons) per day[15], 28% of city demand, at a cost about 37% lower than the cost of potable water from surface water sources, providing blended water to customers.[16],[17]

    In 1985 El Paso Water (EPWater) began using IPR, gaining the trust of its customers. In 2014 EPWater surveyed its customers about using highly treated wastewater into its drinking water system and found that 84% of its customers approved. After outreach efforts, another survey showed that 90% of respondents favored a DPR project.[24]

    EPWater conducted a feasibility study, operated a nine-month pilot program and hired an engineering firm to implement an innovative four-step membrane technology using reverse osmosis, ultraviolet light, disinfection with advanced oxidation and granular activated carbon filtration technology.[24]

    This is the second DPR plant in the world that will provide customers with a permanent DPR source. The plant is being designed with an auditorium and hallway where residents can learn about and see the treatment process, and a room where they can sample the purified water.[24]

    The first large-scale desalination plants were built in the 1960s. There are now about 20,000 facilities globally that convert sea water into fresh water.[1]

    From toilet to tap: how El Paso is fighting drought
    Dec. 4, 2018
    Embedded video, no copy made
    Saudi Arabia has little fresh water and inexpensive energy. Desalination enables it to produce the most fresh water of any nation, one-fifth of the world's total desalinated water.[1]

    Because of low average rainfall during the last two decades, in 2017 the city of Perth in Melbourne, Australia built a $3.5 billion desalination plant that provides a third of the city's water supply.[1]

    Desalinated seawater makes up more than 90% of Israel's domestic water supply. The Sorek Desalination Plant is one of the largest reverse osmosis desalination plants in the world. It provides drinking water for more than 1.5 million people.[23]

    Since January 2016 the San Antonio Water System (SAWS) Brackish Groundwater Desalination Facility, the H2Oaks Center, has been delivering 12 million-gallons-per-day of water to its customers. In the future it is expected to deliver 30 million gallons per day.[25]

    In April 2023 the California Department of Water Resources announced three desalination projects. The city of Torrence in Los Angeles County is constructing a pipeline to connect an existing well to the Goldsworthy Desalter system, increasing the supply of desalinated water by 1,120 acre-feet per year, enough to supply 2,200 homes.[29]

    What does indirect potable reuse (IPR) use that direct potable reuse (DPR) does not?
    The Westland Water District Design Pilot Project in Fresno County will use salt-tolerant plants to desalinate brackishhaving more salinity than fresh water, but not as much as seawater groundwater from an aquifer. The water will provide a cost-effective and reliable water source to Coalinga, Huron and Avenal.[29]

    The city of Fort Bragg Design Pilot Project will use a wave-powered seawater desalination iceberg buoy to provide drinkable water to the community.[29]

    There are two desalination methods and both create environmental problems. Thermal desalination heats water and captures the condensation. Reverse osmosis desalination forces sea water through a membrane that traps salt molecules, allowing smaller water molecules to pass. Both require a lot of energy, producing greenhouse gas emissions contributing to global warming.[1]

    It takes two gallons of sea water to produce one gallon of fresh water. The remaining gallon is very salty and returned to the ocean. If this water is not spread over a large area it can remove ocean oxygen, negatively affecting sea life.[1]

    The cost of desalinated water has dropped by more than half during the last three decades.[1]

    10 Largest Desalination Plants[27]
    plant↕ location↕ daily water production
    m3 per day↕
    method↕ information
    Jebel, Ali UAE 2,227,587 multistage flash distillation (MSF)a sea water desalination process that converts water into steam in multiple stages and reverse osmosis (RO)when a solvent passes through a porous membrane in the direction opposite to that for natural osmosis when subjected to a hydrostatic pressure greater than the osmotic pressure uses the largest gas-fired power plant in the world
    Ras Al Khair Saudi Arabia 1,036,000 MSF and RO uses a gas-fired 2,400 megawatt power station
    Taweelah UAE 909,201 RO largest RO plant in the world
    Shuaiba Saudi Arabia 880,000 MSF wil be upgraded in 2025 to reduce CO2 output
    Umm Al Quwain UAE 682,000 RO functional as of the third quarter of 2023
    Sorek Israel 624,000 RO provides water to 20% of the country's population
    Jubail Saudi Arabia 600,000 RO improved the country's water security
    Rabigh 3 Saudi Arabia 600,000 RO commissioned in 2021
    Fujirah 2 UAE 586,000 MSF and RO has a 2,000 megawatt thermal power station
    Sorek 2 Israel 548,000 RO will begin operating in 2025

    Inside the world's biggest water desalination facility
    WION Dispatch
    Oct. 14, 2020
    Embedded video, no copy made
    [1] Robbins, J. (Jun. 11, 2019). As water scarcity increases, desalination plants are on the rise. YaleEnvironment360. https://e360.yale.edu/features/as-water-scarcity-increases-desalination-plants-are-on-the-rise

    [2] Middel, A., R. Quay & White, D. D. (2013). Water reuse in central Arizona. Decision Center for a desert city technical Report 13-01. Tempe, AZ: Arizona State University. https://d3dqsm2futmewz.cloudfront.net/docs/

    [3] Harris-Lovett, S. R., Binz, C., Sedlak, D. L. & Truffer, B. (2015). Beyond user acceptance: A legitimacy framework for potable water reuse in California. Environmental Science & Technology, 49, 7552-7561. https://pubs.acs.org/doi/pdf/10.1021/acs.est.5b00504

    [4] Environmental Protection Agency. (Sep. 2012). 2012 Guidelines for water reuse. https://nepis.epa.gov/Exe/ZyPDF.cgi/P100FS7K.PDF?Dockey=P100FS7K.PDF

    [5] Hummer, N. & Eden, S. (2016). Potable reuse of water. Arroyo. Water Resources Research Center. Arroyo. https://wrrc.arizona.edu/publication/arroyo-2016-potable-reuse-water

    [6] Mosher, J. & Vartanian, D. (Jan. 2018). Guidance framework for direct potable reuse in Arizona. WateReuse Arizona. https://west.arizona.edu/sites/default/files/2022-02/NWRI-Guidance-Framework-for-DPR-in-Arizona-2018.pdf

    [7] Tchobanoglous, G., et al. (2015). Framework for direct potable reuse. WateReuse Association. https://watereuse.org/watereuse-research/framework-for-direct-potable-reuse/

    [8] Nappier, S. P., Soller, J. A., & Eftim, S. E. (2018). Potable water reuse: What are the microbial risks. Current Environmental Health Reports, 5, 283-292. https://doi.org/10.1007/s40572-018-0195-y

    Which two states are leaders in direct potable reuse efforts?
    [9] Gerrity, D., Pecson, B., & Trussell, R. S., & Trussell, R. R. (Sep. 2013). Potable reuse treatment trains throughout the world. Journal of Water Supply: Research and Technology, 62(6), 321-338. https://iwaponline.com/aqua/article-abstract/62/6/321/29164/Potable-reuse-treatment-trains-throughout-the?redirectedFrom=fulltext

    [10] Belanger, L., Dillow, D., & Higham, D. (Oct. 24, 2019). Water reused in Colorado 2019 update. Interim water resources review committee. https://leg.colorado.gov/sites/default/files/images/committees/2017/wrco_10242019_iwrrc_

    [11] Thomure, T. (n. d.). Potable reuse - A state of the industry update. WateReuse Association. https://watereuse.org/wp-content/uploads/2015/09/Papers-Arizona-State-of-the-Industry-Potable-Reuse.pdf

    [12] Miller, G. W. (May 2015). Total water solutions: Direct potable reuse: Its time has come. Journal American Water Works Association, 107(5), 14-20. https://www.jstor.org/stable/10.2307/jamewatworass.107.5.14

    [13] California Water Boards. (2022). Regulating direct potable reuse in California. State of California. https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/direct_potable_reuse.html

    Why is water blue?
    [14] California State Water Resources Control Board. (Sep. 2016). Investigation on the feasibility of developing uniform water recycling criteria for direct potable water reuse. https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/documents/

    [15] Lahnsteiner, J., Piet du Pisani, P, Menge, J., & Esterhuizen, J. (2013). Chapter 29: More than 40 years of direct potable reuse experience in Windhoek. In V. Lazarova, et al, eds., Milestones in Water Reuse. IWA Publishing. ProQuest Ebook Central. http://ebookcentral.proquest.com/lib/uaz/detail.action?docID=3120231

    [16] Van Rensberg, P. (Feb. 2016). Overcoming global water reuse barriers: the Windhoek experience. International Journal of Water Resources Development, 32(4), 1-15. https://www.tandfonline.com/doi/abs/10.1080/07900627.2015.1129319

    [17] Lahnsteiner, P., van Rensburg, P. & Esterhuizen, J. (2018). Direct potable reuse - A feasible water management option. Journal of Water Reuse and Desalination, 8(1), 14-28. https://iwaponline.com/jwrd/article/8/1/14/38008/Direct-potable-reuse-a-

    [18] Sanchez-Flores, R., Conner, A., & Kaiser, R. A. (2016). The regulatory framework of reclaimed wastewater for potable reuse in the United States. International Journal of Water Resources Development, 32:4, 536-558. https://www.tandfonline.com/doi/full/10.1080/07900627.2015.1129318

    Which city in Namibia uses treated drinking water augmentation?
    [19] Cain, C. R. (Apr. 29, 2011). An analysis of direct potable water reuse acceptance in the United States: Obstacles and opportunities. https://spokaneaquifer.org/wp-content/uploads/2013/10/Direct-Potable-Water-Reuse-Acceptance-Cain_Charla_2011.pdf

    [20] Environmental Protection Agency. (Sep. 2019). Draft Appendix H: Compilation of water reuse action plans. National Water Reuse Action Plan. https://www.epa.gov/sites/default/files/2019-09/documents/water-reuse-2019-appendixh.pdf

    [21] Tortajada, C. & Nambiar, S. (2019). Communications on technological innovations: Potable water reuse. Water, 11(251). https://www.mdpi.com/2073-4441/11/2/251

    [22] Scruggs, C. E., Pratesi, C. B., & Fleck, J. R. (2019). Direct potable water reuse in five arid inland communities: an analysis of factors influencing public acceptance. Journal of Environmental Planning and Management, 63(8), 1470-1500. https://www.tandfonline.com/doi/full/10.1080/09640568.2019.1671815

    [23] Environmental Protection Agency. (Mar. 2023). From water stressed to water secure: Lessons from Israel's water reuse approach.
    2022 U.S. Delegation Summary. https://www.epa.gov/system/files/documents/2023-03/From%20Water%20Stressed%20to%20Water%20Secure%20-%20Lessons%20from%20Israel%27s%20Water%20Reuse%20Approach.pdf

    What liquid metal is more conductive than water?
    [24] Brown, T. (Oct. 10, 2019). El Paso Water to build first-of-its-kind direct potable reuse plant. Treatment Plant Operator. https://www.tpomag.com/online_exclusives/2019/10/el-paso-water-to-build-first-of-its-kind-direct-potable-reuse-plant

    [25] Tetra Tech. (2023). San Antonio desalination plant. https://www.tetratech.com/en/projects/san-antonio-desalination-plant

    [26] TexasConservationAlliance. (Jun. 20, 2019). The facts: Water recycling. https://www.tcatexas.org/post/water-recycling

    [27] Wilson, J. (2023). Desalination plants around the world: The ten largest. Lets Do Water. https://letsdowater.com/the-10-largest-desalination-plants-in-the-world/

    [28] AquaTech. (Mar. 20, 2023). Sothern California: The emerging potable reuse capital of the world? https://www.aquatechtrade.com/news/water-reuse/southern-california

    [29] California Department of Water Resources. (Apr. 19, 2023). California invests in desalination projects to expand water supplies. https://water.ca.gov/News/News-Releases/2023/April-23/California-Invests-in-Water-Supply-and-Research-to-Diversify-Local-Water-Supply#:~:text=Funded%20by%20Proposition%201%2C%20the,Fresno%20and%20Los%20Angeles%20counties.
    [*] Some of the Water Reuse section materials posted in this site originally included in A survey of regulatory, technical, and public outreach challenges and opportunities for direct potable reuse with an emphasis on Tucson and Pima County, Arizona by this author


    California Water Boards. (2016). Conversion Factors. https://www.waterboards.ca.gov/drinking_water/certlic/occupations/ documents/opcert/2016/treat_exam_conversion.pdf

    Calculator.net. (n. d.).

    What are the four salinity classifications?
    convert-unit-measurements.com. (n. d.). Energy conversions.

    Gratzi, Z. (Feb. 3, 2020). Water conversion factors. Complete Water Solutions.

    Minnesota Pollution Control Agency. (2017). Wastewater formulas & conversion factors. https://www.pca.state.mn.us/sites/default/files/wq-wwtp8-03.pdf

    Petrochem. Conversion factors. (n. d.). https://files.knowyourh2o.com/Waterlibrary/watermanual/conversion_factors.pdf


    What is the etymology of the word water?

    Advameg, Inc. (2023). Water encyclopedia. http://www.waterencyclopedia.com/

    Aqua Tech. (Jul. 18, 2022). Morocco declares state of water emergency; Plans to triple desalination capacity. https://www.aquatechtrade.com/news/desalination/morocco-state-of-water-emergency#:~:text=Morocco%20declares%20state%20of%20water%20emergency%3B%20plans%20to%20triple%20desalination%20capacity&text=Morocco%20is%20set%20to%20triple,the%20impacts%20of%20climate%20change.

    Bannister, B., Dean, J. S., & Robinson, W. J. (1969). Tree-ring dates from Utah S-W: Southern Utah area. Laboratory of Tree-Ring Research, University of Arizona. https://repository.arizona.edu/bitstream/handle/10150/220694/tree-ring_dates_utah_s-w.pdf?sequence=3&isAllowed=y

    Derouin, S. (Nov. 3, 2017). Utah's Great Salt Lake has lost half its water. Science. https://www.sciencemag.org/news/2017/11/

    Editors of Encyclopaedia Britannica. (n. d.). Hydrosphere. Encyclopaedia Britannica. https://www.britannica.com/science/hydrosphere/Origin-and-evolution-of-the-hydrosphere

    Environmental Protection Agency. (Apr. 14, 2023). Water infrastructure investments. https://www.epa.gov/infrastructure/water-infrastructure-investments

    Which two water phase changes are the most difficult to observe?
    Fahlund, A., Choy, M. L. J. & Szeptycki, L. (2014). Water in the west. California Journal Politics Policy, 6(1), 61-102. https://escholarship.org/uc/item/0685t8n2

    National Weather Service. (n. d.). Advanced hydrologic prediction service. https://water.weather.gov/ahps2/index.php?wfo=slc

    Sacramento State University. (2019). Water and wastewater terms. https://www.owp.csus.edu/glossary/

    Stockton, C. (Jul. 1983). Projected effects of climatic variation upon water availability in Western United States (progress report). Laboratory of Tree-Ring Research, University of Arizona. https://repository.arizona.edu/handle/10150/303523

    United States 98th Congress. (n. d.). Ak-Chin Settlement Act of 1984. University of New Mexico Digital Repository. https://digitalrepository.unm.edu/nawrs/3/

    What are the two desalination methods?
    USGS. (2023). Current water data for the nation. https://waterdata.usgs.gov/nwis/rt

    USGS. (n. d.). How wet is your state? The water area of each state. https://www.usgs.gov/special-topics/water-science-school/science/how-wet-your-state-water-area-each-state

    USGS. (2023). Surface water data for the nation. https://waterdata.usgs.gov/nwis/sw

    USGS. (n. d.). Utah Water Science Center. https://www.usgs.gov/centers/ut-water/

    Water Education Foundation. (2023). Your online water encyclopedia. https://www.watereducation.org/banner/your-online-water-encyclopedia

    What is special about water`s phases?
    Water Innovations. (Jan. 2023). Top 10 trends for 2023. https://vertassets.blob.core.windows.net/download/d84c9424/d84c9424-4fdc-4e53-8b6c-68e0500bcecf/water_innovations_jan_2023.pdf?vm_tId=2491745&vm_nId=78694&mkt_tok=MDc1LU5WQy0wODYAAAGJbyLMp2XiqZq-kqQCnKGr0i4XB2c_U9SFNiqH-

    Wiley Online. (2023). Water encyclopedia. https://onlinelibrary.wiley.com/doi/book/10.1002/047147844X

    [*] Some of the Hydrology section materials posted in this site originally posted at the Science → Hydrology section of
    Journalism 455/555 Environmental Journalism and John Wesley Powell, 1834-1902, http://denisemeeks.com/journalism/jour_555/powell/ by this author

    Denise Meeks, dmeeks@arizona.edu