Groundwater: Definition, Benefits, Types, Content of Groundwater and Its Damage

sinaumedia Literacy – Groundwater is a source of life for every living thing on earth. Without water, the earth will never have life. Today, the need for water has become the main concern in several countries experiencing a water crisis. Get to know some of the types of water on earth including river water, sea water, rain water, and ground water. Groundwater with its very important role for life. Starting from industrial needs, natural balance, to household needs. Check out a more detailed explanation about Groundwater below!

Definition of Groundwater

Based on Law Number 7 of 2004 concerning Water Resources which defines groundwater as water contained in the layers of rock below the soil surface.

According to Asdak in 2002, groundwater is any form of rainwater flow that flows below the soil surface as a result of the earth’s gravitational force, geological layering structures, and potential differences in soil moisture. This subsurface water is then known as groundwater as you can find a complete explanation in the book Groundwater by Iwayanredana.

Meanwhile, according to experts, the definition of groundwater includes the following:

  • According to Bouwer in 1978, groundwater is a quantity of water below the earth’s surface which can then be collected by wells, tunnels, or drainage systems by pumping. Can also be called a stream that will naturally flow to the ground surface through seepage or a jet.
  • According to Fetter in 1994, groundwater is water that is stored in saturated zones until it moves to various layers and soil rocks on earth until the water comes out as springs, or collects in lakes, ponds, rivers and seas (Fetter, 1994). . The upper limit of the water saturation zone is known as the water table.
  • According to Soemarto, 1989 Groundwater is water that occupies cavities in geological layers. The layer of soil that is located below the soil surface is also known as the saturated zone, with the unsaturated zone that is above the saturated zone up to the ground surface, with its cavities filled with air and water.


Benefits of Groundwater

In general, water has various important benefits for life, not only for humans, but also for various living things on Earth such as animals and plants. With the problems of floods and droughts every year in Indonesia, this water problem is very important to address. Find the solution in the book Groundwater Spatial Planning + Cd.

Because of this, of course, water scarcity will lead to famine, drought, and even species extinction. According to Kodoatie (2012) water that comes from the ground is useful as a source of water for flora, fauna and humans. In addition, water also acts as a major part of the hydrological cycle. Water is then used by humans for daily needs, starting from bathing, drinking, washing, and so on.

Not only humans, all animals also need water to drink and survive, especially aquatic animals that live in water, such as rivers, lakes and oceans. Plants themselves use ground water which is absorbed through the roots to obtain nutrients to support the process of photosynthesis. The following are the benefits of groundwater that you need to know, which include:

  • Groundwater as part of the hydrologic cycle or water cycle that continues to run over and over again
  • Water also functions as a source of electricity generation, for example, in an underground river in the South Gombong karst area, which utilizes underground water flow for independent electricity.
  • Groundwater fulfills various household needs, such as bathing, cooking, drinking and washing
  • Agricultural irrigation, in farmers’ fields which are located far from water sources such as rivers in general, will then make drilled wells to meet the various water needs of agricultural crops
  • Meet various industrial needs that require water in the production process, for example in textile factories that require water in dyeing, the leather industry to clean leather, and so on
  • Groundwater in the form of underground rivers can be a natural research location regarding hydrological systems, biota, and others.
  • The groundwater in the underground caves can then be further developed into tourism objects


Elemental Content of Ground Water

According to Kodatie in 2002, water contained chemical elements according to the groundwater flow system. This groundwater flow system is further divided into three, namely local systems, intermediate systems and regional systems. The chemical elements that dominate the local system include HCO3, Ca, and Mg. Then the intermediate system consists mostly of HCO3, Ca, and Mg. Meanwhile, regional system groundwater contains Na, Cl, and loss of Co2 and O2 elements. Rainwater then seeps below the surface of the soil in the form of infiltration and penetration, it carries various chemical elements.

This abundant rainwater can also be used to fulfill daily needs. Learn how in the book Harvesting Rainwater: A new source of drinking water.

The composition of dissolved substances in groundwater itself can then be further grouped into 4 groups (Hadipurwo, 2006) including:

  • The main elements of groundwater (major constituents) which contain 1.0 – 1000 mg/l, which include calcium, sodium, magnesium, sulfate, chloride, silica, and bicarbonate
  • Groundwater secondary elements (secondary constituents) containing 0.01-10 mg/l, which include iron, strountium, potassium, chlorate, nitrate, boron, and fluoride
  • Minor constituents of groundwater which contain 0.0001-0.1 mg/l, which include aluminum, atymon, arsenic, barium, cadmium, chromium, bromine, cobalt, copper, titanium, vanadium, germanium , iodine, phosphate, rubidium, selenium, lead, lithium, molybdium, nickel, manganese, uranium, and zinc
  • Rare groundwater elements (trace constituents) containing less than 0.001 mg/l, which include beryllium, bismuth, cerium, cesium, gallium, gold, indium, lanthanum, niobium, platinum, radium, ruthenium, scandium, silver, thallium, tharium, tin, tungsten, yttrium, zircon


Ground Water Type

Surface groundwater is water that is above a layer of soil or rock. Groundwater with characteristics starting from the top and bottom of the layer which has a water content which is limited by an impermeable layer. The layer containing water is then located in a cyclical area of ​​a formation that is in the fold area of ​​groundwater, it can emit if it gets pressure on a strong cyclical area, and if the pressure is not strong enough then water can flow up. Surface ground water itself contains many benefits and is often used by humans in various ways, such as agriculture and irrigation. Groundwater can then be classified into 2 types, namely groundwater based on its location on the ground surface and based on where it comes from.

  • Phreatic groundwater is groundwater on a shallow surface which is not far from the ground surface and is above the impermeable layer, for example in well water.
  • Deep Groundwater or also known as Artesian is groundwater that lies between aquifer layers and impermeable rocks, for example in artesian wells. Artesian water is also called deep groundwater, because it can be found at a depth of 30 -80 meters from the ground surface. This groundwater can also be drunk or consumed directly because it has undergone perfect filtering and is free of germs or bacteria. Usually this type of artesian ground water is often used to overcome drought even during long dry seasons. This is because artesian groundwater contains a variety of groundwater with a stable water discharge, although building an artesian well also requires a lot of money because a large capacity special water pump is needed.

While groundwater based on its origin is then divided into 3 types, namely Meteorite Groundwater (Vados), New Groundwater (Juvenil), and Konat Water.

  • Meteorite Groundwater (Vados) is groundwater originating from the process of precipitation (rain) clouds mixed with meteorite dust and then condenses.
  • New Groundwater (Juvenil) is groundwater that originates from within the earth due to magma intrusion pressure, for example in geysers or hot springs.
  • Konat water is groundwater trapped in layers of ancient rocks.

Determinants of Groundwater Quality

The quality of groundwater is determined by the various physical and chemical properties it contains. Based on physical properties, water quality can be determined from the color, smell, taste, turbidity, viscosity and water temperature. The taste of groundwater is also affected by salt elements dissolved or suspended in the water. The viscosity of water is caused by the particles contained in the water, where the more content there is, the thicker the water will be. In addition, the presence of high water temperatures will make the water then more liquid. The turbidity of the water is also influenced by the content of substances that are not soluble in water. For example, in particles of clay, silt, organic matter and microorganisms. Water temperature is also affected by environmental temperature, such as season or weather conditions that occur during the day and night as well as the location of groundwater.

  • Water hardness is the hardness level of water which is generally caused by the elements Ca and Mg. Groundwater with some dissolved metal content, such as Na, Mg, Ca, and Fe. If the groundwater then contains a high amount of metal components then it will cause hard water.
  • Dissolved Solids is the total solids dissolved in groundwater or all the substances left behind after the water has evaporated at a temperature of 103 degrees to 105 degrees Celsius. Raw water used for household needs and drinking water has a maximum content limit of 1,000 mg/l or is referred to as class I water quality standards. These dissolved substances include other organic substances in small quantities, as well as gases and inorganic salts.
  • Electrical Conductivity as the ability of water to conduct electricity. This conductivity is affected by the elemental salt content in the water. The higher the salt element, the higher the electrical conductivity it will have. The conductivity of water is then affected by the dissolved substances, water temperature and chloride ions.
  • Water acidity is then expressed in pH with a measuring scale between 1-14. Water with good quality is one that has a neutral pH content, namely pH 7, if the water pH is more than 7 then it will be alkaline while if it is less than 7 then it will be acidic.
  • Ion content, both cations and anions contained in water, is measured in units of parts per million (ppm) or mg/l. The ions contained in water include Na, K, Zn, Cl, SO4, H2SF, NH4, NO3, NO2, CO2, CO3, HCO3, Ca, Mg, Al, Fe, Mn, Cu, KMnO4, SiO2, Cr , Cd, Hg, Co, boron, metal ions which are usually rare and toxic, such as Pb, Sn, As.


Water Source Damage

Damage to water resources cannot generally be separated from damage to the surroundings, for example population pressure, damage to land and vegetation. These three things are then interrelated and affect the availability of water sources. Of course, this condition also needs to be observed so as not to cause damage to groundwater in the surrounding area. With the existence of problems regarding natural resources, in the utilization for fulfillment of needs there is a law that protects it, and this can be found in Sinaumed’s’ book Law of Water Resources.

Several factors have caused the problem, including the rapid industrial growth in an area accompanied by the growth of human settlements, which will lead to a tendency for groundwater demand to increase. The use of water itself is quite diverse so of course there will be differences in terms of interests, purposes and ways of obtaining water sources. It requires a change in the attitude of most people who currently tend to be wasteful in using water and neglecting the importance of conservation.

Groundwater Problems

Groundwater, especially for household and industrial use in urban and lowland areas, has a tendency to contain organic acids and high levels of iron. This can then result from naturally occurring geological conditions with high Fe deposits, mainly caused by human activities in mountain slope areas. Meanwhile, water with a high organic acid content can be caused by peatlands or mangrove areas which are rich in organic compounds. The characteristics of water containing high organic compound content and high iron content can be seen as follows:

  • Water with high iron content Water will then cause yellow water. When it comes out of the tap the water will appear clear but a few moments after that the water will turn yellow. This is also caused by water coming from a water source before it comes out of the faucet in the form of Fe2+ ions, after coming out of the faucet Fe2+ will be oxidized to Fe3+ which is yellow in color.
  • Permanent yellow water is generally found in mangrove areas and peat soils which are rich in organic compounds. In contrast to the yellow caused by high iron content, this permanent yellow water is yellow when it first comes out of the faucet until after it is left standing it will remain that color.


Groundwater Basins (CAT)

The existence of a water crisis caused by environmental damage requires efforts to maintain the existence or availability of groundwater resources, one of which is by having a groundwater use monitoring system that can be visualized in spatial data and its attributes. Learn how to maintain and manage existing resources through the book Management of Water Resources in Regional Autonomy below.

According to the Law on Water Resources, the groundwater catchment area is called the Groundwater Basin (CAT) which is defined as an area bounded by hydrogeological boundaries, where all hydrogeological events such as the process of stockpiling , flowing and releasing groundwater take place. According to Danaryanto, et al. (2004), CAT in Indonesia is generally divided into two, namely free CAT (unconfined aquifer) and confined aquifer (CAT). These CATs are spread throughout Indonesia with the total amount of potential for each CAT as follows:

  • Free CAT: Potential 1,165,971 million m³/year
  • CAT Depressed: Potential 35,325 million m³/year

The CAT element is all the water that is below the ground surface, so it seems as if it is the opposite of surface water.