[Geography Notes] on Diatomaceous Earth Pdf for Exam

Define Diatomaceous Earth – Diatomaceous Earth (DE) is a naturally occurring, soft and sedimentary rock that can be crumbled into a fine white to off white powder. It is also known as the diatomite or Kieselgur/kieselguhr, with the particle size ranging from less than three micrometres to more than one millimetre, but typically it is from 10 to 200  μm. The powder of the diatomaceous earth can have the abrasive feel the same as the pumice powder depending on the granularity and it has a low density as a result of its high porosity. The diatomaceous earth that is dried in the oven, is 80–90% silica, with 2–4% alumina, and 0.5–2% iron oxide.

Diatomaceous Earth Meaning – It is a fine siliceous earth composed chiefly of the cell walls of diatoms. 

Diatomaceous Earths contains the remaining fossilized diatoms, it is a type of hard-shelled protist. Diatomaceous earth can be used in the filtration aid, mild abrasive products including metal polishes and the toothpaste, mechanical insecticide, matting agent for coatings, absorbent for liquids, thermal insulators, activator in blood clotting studies, cat litter, porous support for the chemical catalysts, anti-block in the plastic films, reinforcing filler in plastics and rubbers, and soil for potted plants and trees like bonsai.

Composition 

The composition of the diatomaceous earth is different for the different deposits, varying with the blend of the pure diatomaceous earth combined with other natural clays and minerals.  The diatoms in each deposit vary in the quantity of the silica, depending on the age of the silica, the species of the diatom can also vary among the deposits. The species of the diatom mainly depends on the age and paleoenvironment of the deposit, in turn, the shape of the diatom is determined by the species.

 

Many deposits in British Columbia, such as Red Lake Earth are derived from the Miocene epoch, which contains Melosira granulata, a diatom species. These diatoms have a small globular form and are around 12 to 13 million years old. A deposit containing diatoms from this epoch will provide significantly more benefits than a deposit from a previous epoch. For example, diatoms from the Eocene epoch which is approximately 40 to 50 million years old are not more effective in their ability to absorb fluid, because as the diatoms get older it recrystallizes and their smaller pores will be filled with silica. 

 

Formation 

The formation of the diatomite occurs by the accumulation of the amorphous silica (opal, SiO₂ . nH₂O), which the remaining dead diatoms in lacustrine or marine sediments. A pair of symmetrical shells, or frustules, make up the fossil remains. Marine diatomites can be found in a number of other rock types, but lacustrine diatomites are almost exclusively found with volcanic rock. The diatomite in diatomaceous chert has been cemented with silica.

 

Diatoms can remove amorphous silica from water with less than 1% amorphous silica saturation. Since they are surrounded by an organic matrix, their frustules do not dissolve. Clay minerals may also form on the frustules, preventing them from dissolving in the seawater. The frustule is stripped of its organic coating and exposed to seawater when the diatom dies. As a result, only 1% to 10% of frustules live long enough to be buried under sediments, and some of this is dissolved. In the sedimentary record, only about 0.05 percent to 0.15 percent of the original amount of silica generated by diatoms is stored.

 

Discovery 

Diatomaceous earth was discovered by German peasant Peter Kasten In 1836 or 1837, when saw sinking a well on the northern slopes of the Haußelberg hill, in the Lüneburg Heath in North Germany.

Extraction and storage sites in the Lüneburg Heath

  • Neuohe – extraction from 1863 to 1994

  • Wiechel from 1871 to 1978

  • Hützel from 1876 to 1969

  • Hösseringen from c.1880 to 1894

  • Hammersdorf from c.1880 to 1920

  • Oberohe from 1884 to 1970

  • Schmarbeck from 1896 to c. 1925

  • Steinbeck from 1897 to 1928

  • Breloh from 1907 to 1975

  • Schwindebeck from 1913 to 1973

  • Hetendorf from 1970 to 1994

Commercial Forms 

Diatomaceous earth is found commercially in many forms:

  • Diatomaceous earth granulated is a raw material that has been crushed for easy packaging.

  • Diatomaceous earth that has been milled or micronized is particularly fine (10 μm to 50 μm) and is used in insecticides.

  • For filters, calcined diatomaceous earth is heat-treated and activated.

Usage 

There are several uses of the diatomaceous earth, some of them are explained below:

  • Explosives – Alfred Nobel in 1866 discovered that absorbing nitroglycerin in diatomite made it much more stable. This makes transporting and treating nitroglycerin in its raw form much safer. In 1867, he patented this mixture as dynamite, and it is also known as guhr dynamite.

  • Filtration – Wilhelm Berkefeld, a Celle engineer, recognised diatomaceous earth’s filtering ability and created tubular filters (also known as filter candles) driven by diatomaceous earth. These Berkefeld filters were successfully used during the cholera outbreak in Hamburg in 1892. Diatomaceous earth, in one form, is used as a filter medium, especially in swimming pools.

  • Abrasive – Diatomite’s oldest application is as a very mild abrasive, and it’s been used in toothpaste, metal polishes, and even some facial scrubs for this reason.

  • Pest Control – Diatomite’s abrasive and physico-sorptive properties make it useful as an insecticide. The fine powder absorbs lipids from the waxy outer layer of several insect exoskeletons, which serves as a shield to prevent water vapour from escaping the insect’s body. The evaporation of water from their bodies is increased when the layer is damaged, causing them to become dehydrated, often fatally.

  • Thermal – Its thermal properties allow it to be used as a fire-resistant safe’s barrier material. It’s also used in cryogenic-safe evacuated powder insulation. To improve the efficacy of vacuum insulation, diatomaceous earth powder is injected into the vacuum room. It was used as a thermal heat barrier in traditional AGA cookers.

  • Catalyst Support – Diatomaceous earth is often used as catalyst support, primarily to increase the surface area and operation of the catalyst. To boost its operation as a hydrogenation catalyst, nickel can be assisted on the material (the combination is known as Ni–Kieselguhr).

  • Agriculture – Natural freshwater diatomaceous earth is used in agriculture as an anti-caking agent and insecticide for grain storage. The Food and Drug Administration has approved it as a feed additive to avoid caking.

  • Construction –  The diatomaceous earth spent in the process of brewing can be added to the ceramics for the manufacturing of red bricks with higher open porosity. Diatomaceous earth is considered one of the most prominent inorganic, non-metallic materials. Which can be used for the production of different ceramics, along with the production of porous ceramics under low-temperature hydrothermal technology.  

[Geography Notes] on Estuary Pdf for Exam

Estuary is the most common term used in the environmental science and earth science branch of the science. In this article, we have covered all the important topics about the estuary like estuary meaning , its type, history, circulation, and human impact on it. Let us discuss the estuary meaning first, An estuary is a brackish water body that is partly enclosed along the shore, with one or more rivers or streams flowing into it and a free access to the open sea. Estuaries serve as an ecotone, or transition region, between river and marine environments. Tides, waves, and the influx of saline water all have an effect on estuaries, as do riverine effects including freshwater flows and sediment. Estuaries are among the most active natural ecosystems on the planet. This is because the mixing of seawater and freshwater produces high levels of nutrients both in the water column and in the sediment.

History of Estuary

Most current estuaries were created during the Holocene period, when sea levels started to rise around 10,000–12,000 years ago, flooding river-eroded or glacially scoured valleys. Estuaries are usually categorised on the basis of geomorphological characteristics or water circulation patterns. Although some of the water bodies do not specifically follow the above mentioned concept of an estuary and may be entirely freshwater, they may be referred to as bays, harbours, lagoons, inlets, or sounds. You may note that estuaries and lagoons are often confused with each other, but they have some key differences in their property and structure.

Types of Estuaries

Drowned River Valley

Coastal plain estuaries are also known as drowned river valleys. Sea water gradually penetrates river valleys in areas where the sea level is rising compared to the surface, and the topography of the estuary resembles that of a river valley. In temperate climates (climate between polar and tropical), this is the most common form of estuary. The Severn Estuary in the United Kingdom and the Ems Dollard on the Dutch-German border are two well known estuaries.

The width-to-depth ratio of these estuaries is normally high, with the inner portion being wedge-shaped, appearing in cross-section, and broadening and deepening as it moves outward. The depth of the estuarine water rarely exceeds 30 metres (nearly 100 feet). The Hudson River, Chesapeake Bay, and Delaware Bay on the Mid-Atlantic coast, and Galveston Bay and Tampa Bay on the Gulf Coast, are examples of this form of estuary.

Lagoon Type or Bar Built

Bar-built estuaries occur where sediment accumulation has kept pace with rising sea levels, resulting in shallow estuaries isolated from the sea by sand spits or barrier islands. In tropical and subtropical areas, they are fairly common.

Barrier beaches keep these estuaries semi-isolated from ocean waters. Therefore, known as barrier islands or barrier spits. The estuary is partly encircled by barrier islands, with only small inlets providing access to the ocean waters. Bar-built estuaries usually form on gently sloping plains near tectonically stable continent edges and marginal sea coasts. They run the length of the Atlantic and Gulf coasts of the United States, where there is active coastal sediment deposition and tidal ranges are less than 4 m (nearly 13 feet). Barrier beaches that surround bar-built estuaries have been established in a variety of ways, including:

  • reworking of sediment drainage from rivers onto beaches, overwash flats, and dunes through wave action, in which sand from the seafloor is deposited in elongated bars parallel to the shoreline.

  • Construction of offshore bars by wave action, in which sand from the seafloor is deposited in elongated bars parallel to the shoreline.

  • Due to sea level rise, engulfment of mainland beach ridges (ridges formed by the erosion of coastal plain sediments about 5000 years ago), resulting in ridge breaching and flooding of the coastal lowlands, creating shallow lagoons.

  • Barrier spits are elongating as a result of headland erosion caused by longshore currents, with the spits rising in the direction of littoral drift.

Fjord Type

Fjords were created when Pleistocene glaciers enlarged and deepened existing river valleys, forming U-shaped cross-sections. They usually occur in the form of rocks, barriers, or sills of glacial deposits at their mouths, which have the effect of altering the estuarine circulation.

Fjord-like estuaries are created by glaciers in deeply eroded valleys. Steep sides, rock bottoms, and underwater sills contoured by glacial movement characterise these U-shaped estuaries. The estuary’s mouth is the shallowest, with sills formed by terminal glacial moraines or rock bars that limit water flow. The depth of the estuary can reach 300 metres in the upper reaches. In general, the width-to-depth ratio is small. Tidal oscillations only impact the water up to the depth of the sill in estuaries with very shallow sills, and the waters deeper than that can stay stagnant for a long time, resulting in only an occasional exchange of the estuary’s deep water with the ocean. Water distribution is less limited when the sill depth is deep, and there is a slow but steady exchange of water between the estuary and the ocean. Along the coasts of Alaska, the Puget Sound area of western Washington state, British Columbia, eastern Canada, Greenland, Iceland, New Zealand, and Norway, fjord-type estuaries can be found also known as estuarine coast.

Tectonically Produced

Land movement associated with faulting, volcanoes, and landslides creates estuaries, which are created by subsidence or land cut off from the ocean by land movement. The construction of these estuaries has also been aided by eustatic sea-level rise during the Holocene Epoch. There are only a few tectonically formed estuaries in the world. The San Francisco Bay, for example, was created by the San Andreas fault system’s crustal motions, which inundated the Sacramento and San Joaquin rivers lower reaches.

Types of Estuary Depending Upon the Water Circulation

Salt Wedge

River production far outnumbers marine input in this form of estuary, and tidal effects are negligible. Freshwater floats on top of seawater in a thin layer that thins out as it goes out to sea. The denser seawater flows landward along the estuary’s floor, creating a wedge-shaped layer that becomes thinner as it gets closer to the shore. Shear forces produce internal waves at the interface as a velocity differential arises between the two layers, mixing the seawater upward with the freshwater. The Mississippi River is an example of a salt wedge river estuary.

Partially Mixed

River production becomes less than marine input as tidal forcing increases. In this case, current-induced turbulence mixes the entire water column, causing salinity to vary more longitudinally than vertically, resulting in a moderately stratified state. The Chesapeake Bay and Narragansett Bay are two examples.

Well Mixed

As tidal mixing forces surpass river output, the water column becomes well-mixed and the vertical salinity gradient vanishes. Because of the extreme turbulent mixing and eddy effects, the freshwater-seawater boundary is removed. Vertically homogeneous estuaries include the lower reaches of Delaware Bay and the Raritan River in New Jersey.

Inverse

In dry climates, where evaporation far outnumbers freshwater inflow, inverse estuaries form. A salinity maximum zone forms, and both riverine and oceanic water flow into it close to the sea. This water is pulled downward and spreads out along the bottom, both seaward and landward. Spencer Gulf estuary located in South Australia is an example of an inverse estuary.

Intermittent

The type of estuary changes significantly depending on the amount of freshwater input, and it can change from a completely marine embayment to any of the other estuary forms.

Impact of Human on Estuary

Estuaries are threatened as habitats by human activities such as deforestation and overfishing. Sewage, coastal settlement, land clearing, and other factors all pose a threat to them. Events far upstream have an effect on estuaries, which concentrate materials including toxins and sediments. Land runoff, mining, agricultural, and residential waste all join waterways and end up in estuaries. Plastics, pesticides, furans, dioxins, phenols, and heavy metals are examples of contaminants that do not degrade quickly in the marine setting.

Toxins can build up (bioaccumulation) in the tissues of many aquatic organisms, a process known as bioaccumulation. They also build up in benthic ecosystems including estuaries and bay muds, providing a geological record of human activities from the previous century. The abiotic and biotic components of biofilm reflect areas of the estuary impacted by human activities, and over time can shift the basic composition of the ecosystem, as well as the reversible or permanent changes in the abiotic and biotic sections of the systems from the bottom up.

For example, industrial contamination from China and Russia, such as phenols and heavy metals, has decimated fish populations in the Amur River and harmed the soil in its estuary.

Since nutrients are discharged into estuaries by land runoff, estuaries are naturally eutrophic. Land run-off now contains many chemicals used as fertilisers in agriculture, as well as waste from animals and people, due to human activities. Hypoxia and the formation of dead zones will occur when there are too many oxygen-depleting chemicals in the water. Water quality, fish, and other animal populations can suffer as a result. Overfishing is also an issue. Overfishing has nearly wiped out a once-thriving oyster community in the Chesapeake Bay. These contaminants are filtered by oysters, which either eat them or shape them into small packets that float to the bottom, where they are harmless. The oysters used to filter the entire volume of water in the estuary of excess nutrients every three or four days. Today, the process takes nearly a year, and sediment, nutrients, and algae can wreak havoc on local waters.

Estuarine Circulation

Microtidal, mesotidal, and macrotidal tidal ranges, as well as topography, such as submerged river valleys and fjords, and morphological classification, can all be used to classify stuaries. Estuaries are classified by oceanographers according to their salinity composition, or the ratio of freshwater input to seawater mixed by the tides (Dyer, 1997).

The conflicting powers of freshwater from riverine inflow and the influx of seawater through tidal waves and turbulent mixing decide the circulation of an estuary, with local winds and bathymetry playing a minor role. The salinity variations along the estuary are typically so high that the density differences that result dictate circulation. The circulation is normally dominated by along-channel flow, while across-channel flow may be an order of magnitude smaller. As a result, a two-dimensional velocity regime is often used to define circulation.

The ratio of freshwater input to mixed seawater, which specifies the properties and salinity distribution of each estuary, can be used to classify them. Finally, the properties that define estuarine circulation would have an effect on the estuary’s connectivity. The most critical forms of estuaries are: 

We can measure this by comparing the amount of freshwater entering the river during one tidal time to the volume of water carried into the estuary and withdrawn during one tidal cycle (Tomczak and Godfrey, 1994). Estuaries can be of any size and still belong to the same type since the ratio of freshwater to tidal volume is significant.

Did you know that?

  • Estuaries are among the world’s most active habitats.

  • Estuaries are very fragile habitats.

  • Positive, inverse, and low-inflow estuaries are the three types of estuaries classified by water balance.

[Geography Notes] on Fumarole Pdf for Exam

A fumarole is a word that originates from the Latin word ‘fumus’ meaning smoke. A fumarole is an opening in the planet’s crust that emits steam and gases like carbon dioxide, sulphur dioxide, hydrogen sulphide, and hydrogen chloride. The steam from the fumarole becomes superheated when the water boils and the pressure drops when it emerges from the ground. Solfatara is the name of the fumarole which emits sulphurous gases. Fumarole occurs along the tiny cracks, fissure or through the chaotic clusters or the fields.  

Fumaroles occur on the surface of the lava or the pyroclastic flows. A fumarole field is the area of the thermal springs, here the gas vents where the shallow magma or the hot igneous rocks releases the gases or it interacts with the groundwater.  The fumaroles occurring in the freezing condition may cause fumarolic ice towers.  

Fumarole 

A fumarole is a vent on the Earth’s surface. From this fumarole, the steam and the volcanic gases gush out. The main source of the water vapour which emits by the fumaroles is the groundwater which is being heated by the bodies of magma that lies relatively close to the surface. Carbon dioxide, Hydrogen Sulphide, Sulphur Dioxide usually is emitted directly from the magma. The Fumaroles are generally present on active volcanoes which occur during the period of relative quiet between the eruptions.  

Fumaroles are closely related to the hot springs and geysers. In these areas the water table rises near the surface, the fumarole then becomes hot springs.  A fumarole that is rich in sulphur is called a solfatara while a fumarole that is rich in carbon dioxide is called mofette. 

Steam Cave and Vent Sites

Geographical features like fumaroles or steam vents are found on the Big Island of Hawaii Island. Steam caves and vent sites are the least studied thermal features, while these are the only terrestrial hydrothermal feature which is readily available for investigation on the Hawaii Island. Although they are considered to be a lack in the living microbes due to their temperatures. The steam that is filled in the caves and vents of Hawaii are found to contain a broad diversity of microorganisms. Steam is formed from the meteoric waters that descend into the subsurface and then they meet upward as convection of heat. 

The steam then quickly forms, by rising vertically to the surface through the crevices and from the fissures in the lava. As this comes near the surface, it fills horizontally or vertically in the caves and it exits the passageway in a continuous or in the form of burst-like structure. This depends on the flow of the rate.

Although some of these caves have high burst discharge which is emitted out of it, the steam can be considered to be an artesian flow. Physically these steam caves can be either shallow, which can be 1 m or less, or this can be deeper to several meters, within the narrow or wide openings.

Hot Springs and Geysers

Hot Springs and Geysers are the manifestations of volcanic activity. They are the result of the interaction of the groundwater with the magma which then solidifies when it has hot igneous rocks at its shallow depths.  

The Yellowstone National Park which is in the United States is one of the most famous areas of the hot springs and geysers in the world. 

The total heat emitted out from these thermal features is estimated to be approximately 300 megawatts. The last great eruption which happened at the Yellowstone occurred around 630,000 years ago when some 1,000 cubic km of the rhyolitic pumice was ejected in huge pyroclastic flows and this resulted in the formation of the caldera.  

Yellowstone lake occupies part of the giant caldera.  This is the last great outburst which happened about 1,200 cubic km (288 cubic miles) of the rhyolite lava which flowed and formed domes that have erupted in numerous smaller events. The cooling roots are those which had past eruptions, or it has possibly been new intrusions of magma at the shallow depth. Here emit the heat sources for the Yellowstone hot springs and geysers.

Geysers are the hot springs that intermittently spout a column of hot water and steam into the air column. This action of the geyser is caused by the water in deep conduits which is beneath the geyser and they approach or reach the boiling point. At around 300 metres below the surface, the boiling point of water increases to around 230 °C (or 450 °F), for this there is an increase in the pressure of the overlying water. When the bubbles of steam or any dissolved gas begin to form, and they rise up, they expand, forming hot water spills from the geyser’s vent, this lowers the pressure on the water column below. The water at depth then momentarily exceeds its initial boiling point and then it flashes into steam, this forces additional water from the vent. This is a chain reaction that continues until the geyser exhausts off its supply of boiling water.

[Geography Notes] on Gulf – Coastal Feature Pdf for Exam

The gulf is any of the coastal indentations i.e. any of the deep recess or notch on the edge of a coastline. Regardless of the size, depth, configuration and geologic structure the gulf coastal feature is an inward-pointing feature of the ocean. There is wide variation in the naming of the gulfs. Different names depending on the size of various gulf coastal regions used are bay, bight, firth, sound, and fjord. Many of these pronounced features around the oceanic margins have no name at all. This leads to some of the characteristics of such gulf coastal features also being applied to bays, and other similar geographical features as well. 

Topographical Characteristics of Gulf Coastal Regions

Some of the features of a single gulf coastal region are formed along the linear shores of the continents. When there is any irregularity in the shoreline then there are high chances of formation of different small and complex geological features which can lead to the formation of groups of gulfs that may or may not be similar. Most of these features of the shorelines can have inward-facing coastal features which are also known as bays. This also leads to diversity in the topographic features of the Gulf coastal regions. 

Along with the shapes, there is also much diversity in the bottom topography of the gulfs. The factors that contribute to the diversity are heavily influenced by the geological structure and development in the given region. Simple shapes and shallow depths are formed from homogenous bedrock of low strengths or resistance. An example of such a case is the Gulf of Riga in the Baltic Sea. At some places, the gulfs are in the form of long narrow arms giving almost parallel shores extending inwards. Such regions occupy the troughs that were created during a period of low sea level. On the other hand, deep angular gulfs are formed along with the features of fractures, faults and rifts having an irregular bottom topography. Some of the gulfs have extremely deep and narrow coastal features with parallel shores. Some of the fjord-gulfs are noted for their very high length-to-width ratios. Regions with non-uniform deformation and uplift form gulfs that are irregularly shaped and complicated having a distinct bottom topography as well. 

The gulfs are usually connected to the sea via straits. There are gulfs where there is an archipelago at its mouth and some of the gulfs open into the sea or into other gulfs present on the opposite sides for which examples include the Gulf of Aden and Gulf of Oman.

Factors Affecting the Characteristics of the Gulfs

Gulfs can be different from the nearby ocean or sea, because of the water properties and dynamics, and sedimentation processes. The size and shape of a given gulf along with its depth and bottom topography determines the differences of the gulf with the nearby waterbody. These differences also depend on the degree of isolation of the gulf with the waterbody. The degree of isolation depends on the ratio of the mouth of the gulf to the total surface area of the gulf or the ratio of the cross-sectional area of the mouth to the total volume of the water. In the case of a submarine ridge or rise feature of the sill, the ratio of the depth above the sill to the depth of the gulf is of significance. But there hasn’t been any comparisons in-between any such ratios and because of this, the variables that control the ratios are qualitative rather than quantitative. 

The water exchange between the ocean and the gulf is hampered by the high sill leading to oxygen deficiency by stagnation like in the fjords of Norway, the Red Sea and the Black Sea. This is because the presence of the sill causes independent circulation of the gulf waters, which are generated by the local winds and the run-off of the rivers. Sills are usually dispensable for the formation of independent circulation. A narrow mouth like in the Gulf of Bothnia will lead to the same result. The water of the gulfs is freshened by the river runoff in humid climates. The salinity is low in the Gulf of the Baltic Sea along with the southern coast of the Kara Sea. The water only becomes fresh in the head especially in the spring when usually the snow begins to thaw. The arid zone of the gulfs suffer from intensive evaporation and some of it is received from the little river runoff. This makes the salinity increase in the climatic regime. In addition to this effect, the runoff delivers the organic matter and the nutrient salts that might determine the specific features of life in the gulfs. The organisms develop in quantities and belong to many different species and a number of genera. Hence, industries focused on shrimp, oyster and other fisheries got concentrated into the gulfs.

Gulf Classification

The formation of the gulfs and its geologic structure and development history is varied. Depending on the factors discussed above for the formation of the gulf. These factors allow some degree of classification. The following classification is based on some of these 

  • A1: Areas with open concavities of the continental coast

  • A2: Large gulf areas isolated from the oceans

  • A3: Ocean gulfs that are isolated from the water bodies but to a lesser extent

  • B: Gulf features situated on the continental shelf

  • C1: Intercontinental gulf basins of the sea including the deepwater part

  • C2: Intercontinental gulfs with both deepwater and shelf gulf parts

[Geography Notes] on Hydrology Pdf for Exam

Hydrology is defined as the science that is concerned with all the aspects of water available on Earth. It deals with the study of the occurrence of water, its distribution, its properties, and circulation of water on Earth and other Planets including water resources, water cycle, and watershed sustainability.

A professional of hydrology is known as a hydrologist. Using different scientific techniques and analytical methods, hydrologists collect and analyze data to resolve water-related problems such as natural disasters, environmental preservation, and water management.

Hydrology Meaning

Understanding Hydrology’s meaning is extremely important, as it is the science that deals with one of the most valuable resources on Earth known as Water. All aspects of the availability of water on Earth are studied by hydrologists to know the ways to manage this vital resource. Hydrologists rely on their understanding of how water interacts with its environment, including how it circulated from the Earth’s surface to the atmosphere, and then how it returns to Earth. This never-ending process of movement of water is known as the hydrologic cycle or the water cycle.

The field of hydrology consists not only of studying the natural distribution and circulation of water, but it is also concerned with the impact of human activities on water quality and with problems in water management. Water is used by humans for different purposes. In homes, water is used for drinking, cooking, cleaning, and bathing. Many industries require large amounts of water. In agriculture, water is required for the irrigation of farmland and livestock. Water available in dams is used to produce hydroelectric power. The human uses of water are endless.

What is Hydrology?

Hydrology is the science that encompasses the study of water on Earth’s surface and underneath the Earth surface, the occurrence and circulation of water, the physical and chemical properties of water, and its relationship with the human and material components of the environment. Eventually, the hydrology questions include the transfer of energy, nutrients, solutes, contaminates, or sediments as well as the water fluxes itself.

The hydrologic cycle or water cycle is the continuous process through which water gets purified by evaporation and transported from the Earth’s surface (including the oceans) to the atmosphere and return to the land and the oceans. This happens through different concepts at different rates but the core concepts remain the same.

Water vaporizes or evaporates from the ocean, liquidizes as clouds, moves over land, and precipitates. From there it can reach the groundwater, vaporize again, or enter a stream or lake. It will ultimately find its way to return to the ocean either by falling as precipitation, flowing with a river or by moving slowly with groundwater.

The hydrologic cycle is also a process that transforms heat energy. Heat is transported towards the poles of the Earth by water being vaporized or evaporated and then condensing which releases heat. Without the water cycle, the climate would be much more frozen, and areas that are away from the equator would become inhabitable.

Hydrology Application

  • Hydrology helps to calculate the rainfall

  • Hydrology helps to calculate the surface runoff and precipitation

  • Designing bridges, sewers, irrigation schemes, and  urban drainage systems

  • Provides clean drinking water

  • Designing dams for hydroelectric power irrigation or water supply

  • Real-time flood warning and forecasting

  • Determining the water balance of a region and agricultural water balance.

  • Estimating or predicting the flood, landslide, or drought risk

  • Helping to analyze the impacts of antecedent moisture on the sanitary sewer system

  • Helps to predict geomorphology changes such as erosion or sedimentation

  • Managing agricultural productivity, and many more.

Did You Know?

  • Of all the availability of water on Earth, only 1% of it is suitable for human use.

  • Only 3% of the water available on Earth is freshwater available for drinking.

  • Precipitation can come about in the form of rain, sleet, snow, or hail.

  • When water evaporates into the atmosphere, it cools and condenses to form clouds through a process known as condensation.

  • When the clouds become too heavy from collecting water, it releases through a process known as precipitation.

  • 70% of the human brain is made up of water.

  • The Earth’s hydrologic cycle began about 3.8 billion years ago when rain fell on Earth forming oceans

[Geography Notes] on Introduction to Industry Pdf for Exam

Have you ever wondered where all the smartphones, laptops come from? You go to a relevant shop to purchase the product you want but from where does that product come into existence in that particular shop? The shopkeeper purchases that product from his or her distributor and the distributor purchases from the manufacturer. The manufacturer produces the final product which is made available in the shop from the raw materials. 

Therefore the manufacturer is the origin of any product. 

An industry is a group of many organizations involved in the production as well as in the manufacturing or handling of the same type of product and service. All the industries are part of the secondary activity. The secondary or the manufacturing converts all the raw materials into products of more value to the people. 

Basically, the industry refers to the economic activities concerned with the production of the goods, extraction of the services as well as provisions or services. Therefore one can say that an industry is concerned with the following:

  • Production of a good that is steel energy.

  • Extraction of the materials that are coal mining.

  • Provisions for the services that are tourism. 

  • There are also emerging industries such as sunrise industries. 

Classification of Industries in India

Raw Materials

  • Agro-Based Industries – These industries use plants and also animal-based products as their raw materials. For example food processing, vegetable oil, cotton textile, dairy products, and also the leather industries. 

  • Mineral-Based Industries– The mineral-based industries are based on mining and use mineral ore as the raw material. These industries also provide to other various industries and they are used for heavy machinery as well as building materials.

  • Marine-Based Industries– These industries use raw materials from the sea or the ocean. For example- fish oil.

  • Forest-Based Industries – The Forest-based industries use their raw materials from the forest like wood. The industries connected with the forests are paper, pharmaceutical, and furniture.

Size

The size of industries is measured by how much money is invested, employee count, and also the goods produced.

  • Small-Scale Industries – The small-scale industries have less capital and technology invested in them. There is often manual labor noticed here. For example, Basket Weaving, pottery, and handicrafts.

  • Large-Scale Industries – The large-scale industries are totally the opposite of that of small-scale industries and here the capital invested is large and advanced technology is in use here. For Example, automobiles and also Heavy Machinery.

Ownership

  • Private Sector – Private industries are businesses that are owned and also operated by an individual or a group of individuals.

  • Public Sector – Public industries are owned and also managed by the government. For example, Hindustan Aeronautics Limited (HAL)

  • Joint Sector Industries – Joint sector industries are jointly operated by the state and individuals. For example, Maruti Udyog.

  • Cooperative Sector Industries – Cooperative industries are operated by the suppliers, the producers, or the workers of raw material. For example, Amul India.

Industrial Distribution in India

Iron and Steel Industry

The iron and steel industries are known as the feeders of all other industries because the products of these industries are used as raw materials in other industries. 

The input includes raw materials such as iron ore, labor, capital, and also other infrastructure. Iron ore is converted into steel by various processes. 

Finally, the output is steel which is the basic material needed in every other industry. 

Textile Industry

The textile industry is one of the oldest industries in the world which was revolutionized during British rule in India. There are very few demanded fibers such as Muslins from Dhaka Chintzes and Calicos, Gold wrought cotton from Surat, Burhanpur, and Vadodara.

The very famous cloth type which was exported across the countries of Egypt, China etc is the famous Block-printed cotton fabrics from Gujarat. During the prevalence of the Barter system, north Indian silks were exchanged to get their Western Spices. It was even exported in large quantities through the Silk route of China. Textile manufacturing was a largely widespread field during the Mughal Empire. From simple Opium dyed clothes to khadi, India has a long history of Textiles. 

Information Technology

Information technology deals with the storage, processing, and distribution of information and it has gained global attention. India started IT services in Mumbai in 1967. This came into existence with the creation of Tata Consultancy Services. The Tata Consultancy Services officially collaborated with Burroughs, which brought an initiation to IT export services. In the world of economics, India is the largest exporter of IT. It constitutes about 79% of the total revenue. The major information technology hubs in India are:

Bangalore is Indias’ biggest tech hub. It records 38% of the total IT exports making a net worth of [$]45 billion to India and is thus called the “Silicon Valley of India ”. 

Hyderabad is the largest bioinformatics company in India. Remarkable tech troops include Accenture, Amazon, Deloitte, Tata Consultancy Services, Microsoft, HCL Technologies, Oracle Corporation, Google, Qualcomm, Dell, Cognizant. 

Chennai is the third-largest exporter of IT. TIDEL Park in Chennai was recognized as the largest IT park built in Asia. 

Rajiv Gandhi infotech park worth ₹600 billion is located in Pune.  

Cities like Gurgoan and Noida in Delhi have contributed to the techno industries of the world on a notable scale. 

Classification of Agro-Based Industries

Agro-based industries can be classified into two categories- first the food processing industries and second the nonfood processing industries. Food processing industries generally deal with the preservation of perishable products as well as the utilization of by-products for other purposes. Indias’ capital income and dependency are on agriculture. Thus its significance is also equally high. The economic statistics report of India states that about 18% of the GDP is coming from the agricultural sector. People from different shades of the country are depending on agriculture for their living. However, it is apparently visible that the share of the population working in this humble industry is decreasing day by day. So India is not very far from facing scarcity in case people are putting their efforts into cultivation and raw material production. 

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