Classification schemes of Water – The detalied classification system
There are multiple different ways to classify water, such as by discipline, by origin, by salinity, and by chemical properties. In this article we will discuss the first 3 major classification scheme of water.
A. Classification of water by decipline:
- Ground water: usually water associated with the saturated zone. A very common term for hydrogeologits or geohydrologists.
- Surface water: water from streams, rivers, lakes etc, also studied by hydrogeologits and geomorphologists.
- Soil water: usually refer to water associated with the “vadose zone”. A very common term for soil scientists and hydrogeologists.
- Waste water: Typically sewage effluent and treated effluent. A very common term used by sanitary or environmental scientists.
B. Classification of water by Origin ( reference Donald White, 1960)
- Juvenile water: Any water that is new to the hydrogeologic cycle, for example, emanating from magmatism, volcanism and metemorphism.
- Metamorphic water: water produced deep within the crust (Juvenile water) resulting from degassing and hydration of minerals as they are metamorphically converted to more stable forms. for example Tremonite + calcite +quartx –> diopside + CO2 + water (not balanced); this water exist conceptually and may be volumetrically significant but it is not obtainable.
- Meteoric water: water that has recently been associated with the hydrologic cycle and can return to the hydrologic cycle. This is water that recharges aquifers by precipitation. This is obviously the most common origin of all groundwater and extremely significant.
- Magmatic water: water deriving from magmatism or melting of rocks (juvenile water). Note: All magmatic water is juvenile water. The standard of origin of oceans of from some magmatic source.
- Phreatic Explotion water: This is geyser type of water emerging from below a volcano, incipent volcanic eruption, or some other hydrothermaly active sites. Most of this water is in fact metamorphically derived water.
- Cometary water: there has been a controversy ranging since the 1980’s in the field of astronomy focussed upon the existence of microcomets that constantly bombard the earth. These comets have been :imaged” by modern spectroscopic satellite methods; however, astronomers are not always convinced of their reality. These collisions are so numerous that the microcomets (comets are mostly water and organic debris) can account for all the water in oceans. This is controvertial and one has to ask why Mars and the Moon are not covered with such oceans as those comets must have had strike their surfaces too.
- Hydrothermal Water: This refers to hot and deep ground water. Due to high lithostatic pressure, water can stay within the liquid phase to amazingly high temperature (>600 oC). Most hydrothermal water has been shown to be meteoric in origin.
- Fossil or Connate water: This was formerly referred to as “formational water” in petroleum field. They are water from great depths, usually as the result of petroleum extraction, and are usually brine in nature. Connate water was originally thought to represent ocean water buried with the rock. However, this now known not to be the case. These water do not isotopically or chemically match the sea water of any supposed geologic period and have been diagenetically altered. Their evolution is more important than their origin. Without human intervention (i.e. pumping) these fluids are typically isolated from the hydrologic cycle for very long time ( may have been for hundreds of millions of years)
C. Classification of water by Salinity:
The unit od measure is TDS = Total Dissolved Solids in milligrams per liter (mg/l) or parts per million (ppm)
Note: This is a loose definition and other sources may vary in range.
- Fresh water: 0-1000 mg/l TDS
- Drinking water: 0-500 mg/l TDS
- Brakish water: 2000 – 20,000 mg/l TDS
- Normal marine water: 35,000 mg/l TDS
- Brine: 100,000 – 300,000 mg/l TDS or 10-30% salt by weight.
If you are aware of any other classification scheme of water, please reply to the post. I will try to add them ASAP.