Syllabus- India – Physical setting, Physiography, Drainage, Soils, Vegetation and Wildlife Degradation and Conservation Measures.
Number of questions- Mains: 02, Prelims – 10
Mains Questions of the day-
1.Data Bank of ISRO shows around 30% of the Total Geographic Area of the country has undergone land degradation during 2018-19. In this context, what is land degradation and desertification and explain the measures to tackle that issue?
Introduction: –
Write briefly about Land degradation and Desertification.
Body: –
Write the measures to handle the Land Degradation and Desertification issue.
Conclusion: –
- In Banni region of Rann of Kutch, land restoration was done by developing grasslands, which helped in achieving land degradation neutrality.
- It also supports pastoral activities and livelihood by promoting animal husbandry.
- Thus restoration of land can be contributing to: –
- Increase the soil fertility
- Increased land productivity
- Food security and
- Improved livelihoods.
Content: –
Land degradation and Desertification
- Land degradation is defined as a negative trend in land condition, caused by direct or indirect human-induced processes including anthropogenic climate change, expressed as long-term reduction or loss of at least one of the following:
- Biological productivity
- Ecological integrity or
- Value to humans.
- Forest degradation is land degradation that occurs in forest land.
- Land degradation within dryland regions (arid, semiarid and dry sub-humid regions) is termed as Desertification, which turns fertile land into desert.
- Data bank (Desertification and Land Degradation Atlas of India- ISRO) shows: –
- Around 30% of the Total Geographic Area (TGA) of the country has undergone land degradation during 2018-19.
- States like Jharkhand, Rajasthan, Delhi, Gujarat, and Goa have more than 50% of their area under desertification/ land degradation.
Following measures can help tackle the issue of land degradation:
- Utilizing Local and indigenous knowledge for addressing land degradation:
It can help to introduce, implement, adapt and promote the use of locally appropriate responses.
- Promoting Agroforestry:
Agroforestry needs to be made an economically viable option through policy and institutional interventions such as R&D, development and provision of quality planting material, price support instruments and mechanisms, etc.
- Improving Agronomic practices:
Agricultural practices that can help reduce land degradation: –
- retention of residues and reduced tillage (or no-tillage)
- use of locally adapted varieties
- inter-cropping and crop rotations
- cultivation of cover crops (green manure crops and catch crops that are grown between the main cropping seasons)
- Integrated soil fertility management.
- Land reclamation programmes:
- Land reclamation means creating land either by removing water from muddy areas or raising the level of the land.
- With an increasing demand for land, it can be a good solution for creating areas for building, agriculture and other uses.
- They can help to reduce extreme weather conditions associated with desertification by acting as “green walls” that reduce sand and wind erosion.
- For instance, the Great Green Wall initiative launched in 2007 by the African Union, is an initiative to restore Africa’s degraded landscapes and transform degraded Sahel region.
- Sustainable forest management (SFM):
SFM aimed at providing timber, fibre, biomass and non-timber resources can provide: –
- long-term livelihood for communities
- reduce the risk of forest conversion to non-forest uses and
- maintain land productivity
Thus reducing the risks of land degradation.
Impacts of Land Degradation and Desertification: –
• Socio-Economic impacts:
- Reduces land productivity threatening food security and livelihoods of indigenous populations, small farmers etc.
- Reduces the land’s ability to store water resulting in water scarcity.
- Exacerbates existing societal tensions and forces migration.
• Impact on Human health:
- Creates ground for zoonotic disease, water- and foodborne diseases and respiratory diseases.
- Higher threats of malnutrition from reduced food and water supplies.
• Environmental impacts:
- Causes extreme weather events, accelerates biodiversity loss and disruption of ecosystem services.
- Contributes to Climate Change: Land degradation is a driver of climate change through emission of greenhouse gases (GHGs) and reduced ability of land to act as a carbon sink.
2.Ministry of Earth Sciences in coordination with Mumbai Municipal Corporation developed an Integrated Flood Warning System for Urban flooding. What is Urban Flooding and mention the factors contributing to Urban flooding?
Introduction: –
Write briefly about urban flooding.
Body: –
Mention the factors contributing to Urban flooding.
Conclusion: –
- Integrated approach should be adopted for sustainable urban planning by empowering and educating Urban Local Bodies in decision making and planning of flood mitigation infrastructure.
- Focus on increasing the resilience of communities and adaptive capacity of our infrastructure is needed.
- Urban design and planning should be water sensitive and take into consideration the topography, types of surfaces (pervious or impervious), natural drainage etc.
- Vulnerability analyses and risk assessments should form part of city master plans.
- Disabling encroachment in sensitive zones through robust anti-encroachment laws and by providing adequate affordable housing can help reduce number of persons vulnerable to changing climate.
- Prevent encroachment on the river basin & natural lakes to ensure natural flow of the water.
Content: –
Urban flooding: –
- Urban flooding is the inundation of property in an environment, particularly in densely populated urban areas, caused by intense rainfall (on impermeable surfaces) which overwhelms the capacity of drainage systems.
- It is significantly different from rural flooding as urbanisation leads to:
- increase the flood peaks from 1.8 to 8 times and
- flood volumes by up to 6 times.
Consequently, flooding occurs very quickly due to faster flow times, sometimes in a matter of minutes.
- There has been an increasing trend of urban flood disasters in India in recent years whereby major cities like Mumbai, Chennai, Delhi, Kolkata etc. have been severely affected.
- Urban flooding has wide ranging impacts: –
- Damage to vital urban infrastructure causing disruptions in transport and power.
- Loss of life and damage to property
- Risk of epidemics due to exposure to waterborne and vector borne infections
- Deterioration of water quality
- Economic losses due to disruption in industrial activity, supply chains etc.
- Displacement of population in low lying areas
- Accidents and fires due to short circuit
Factors Contributing to Urban Flooding: –
- Human Factors: –
- Land use changes (e.g. surface sealing due to urbanization, deforestation) increase runoff and sedimentation.
- Encroachment of the flood plain and thereby obstructing flows.
- Inefficiency or non-maintenance of flood management infrastructure
- Climate change affects magnitude and frequency of precipitation and floods, and also causes extreme weather events.
- Changing Urban micro-climate due to urban heat island effect may enforce precipitation events
- Sudden release of water from dams located upstream of cities/towns
- Indiscriminate disposal of solid waste leading to blocked drainage systems
- Hydrological Factors: –
- High tide impeding drainage.
- Presence of impermeable cover
- High Soil moisture levels
- Low Natural surface infiltration rate
- Absence of over bank flow, channel network
- Meteorological Factors: –
- Heavy Rainfall
- Cyclonic storms
- Small-scale storms
- Cloudburst
- Bursting of glacial lakes
- Climate Change: –
Climate change due to various anthropogenic events has led to extreme weather events.
Prelims Questions of the day: –
1. Which of the following statements is correct about black soil?
- It is generally rich in phosphoric contents.
- It is made up of very coarse material.
- It can hold moisture.
- It is formed after the weathering of metamorphic rocks over a long period of time.
Answer : C
Explanation-
- These soils are generally poor in phosphoric contents. So, (a) is wrong. It is however rich in soil nutrients, such as calcium carbonate, magnesium, potash and lime.
- The black soils are made up of extremely fine i.e. clayey material. They are well-known for their capacity to hold moisture. So, (b) is wrong, and (c) is correct.
- It is typical of the Deccan trap (Basalt) region spread over northwest Deccan plateau and is made up of lava flows. So, (d) is wrong.
2.‘Pedestal rocks’ are a result of which of the following denudational process?
- Aeolian erosion
- Karst deposition
- Glacial deposition
- Riverine erosion
Answer: A.
Explanation:
- Many rock-outcrops in the deserts are easily susceptible to wind deflation and abrasion. They are worn out by winds leaving some remnants of resistant rocks polished beautifully in the shape of mushroom with a slender stalk and a broad and rounded pear-shaped cap above.
- These rocks are called mushroom rocks.
- Sometimes, the top surface is broad like a tabletop and the remnants stand out like pedestals. Thus they are also called pedestal rocks.
- Hence A is the correct answer.
3.Which of the following ideas proposed that earth formed out of a cloud of materials associated with youthful sun?
- Nebular hypothesis
- Binary theory
- Big Bang theory
- Planetesimal hypothesis
Answer: A.
Explanation:
- The Nebular hypothesis (Initially given by Immanuel Kant, and Laplace revised it later) considered that the planets were formed out of a cloud of material associated with a youthful sun. The cloud of materials is called a Nebula. (Hence option A is correct)
- Binary theories proposed that planets were formed as a result of interaction between the sun and a companion star. (Hence option B is incorrect)
- Big Bang Theory (also called as expanding universe theory) proposed that universe formed from a tiny ball with unimaginably small volume, infinite density, and temperature. (Hence option C is incorrect)
- Planetesimal hypothesis (given by Chamberlain and Moulton) considered that a wandering star approached the sun. Due to its gravitational pull, a cigar-shaped extension of material was separated from the solar surface. As the wandering star moved away, the material separated from the solar surface continued to revolve around the sun and it slowly condensed into rounded objects called planetesimals. These planetesimals eventually became planets. (Hence option D is incorrect)
4.In the evolution of the earth, the term ‘degassing’ refers to which of the following?
- The process in which the earths’ early atmosphere was stripped off by solar winds.
- The process in which gases were outpoured from the interior of the earth.
- The process in which carbon dioxide was removed through photosynthesis.
- The dissolution of atmospheric carbon dioxide in the rainwater.
Answer: B.
Explanation:
- During the cooling of the earth, gases and water vapor were released from the interior of solid earth.
- This started the evolution of the present atmosphere.
- The process through which the gases were outpoured from the interior is called degassing.
- Hence B is the correct answer.
5.Which of the following is a direct source of information about the interior of the earth?
- Volcanic eruptions
- Meteors
- Gravity anomaly
- Earthquakes
Answer: A.
Explanation:
- Most of our knowledge about the interior of the earth is largely based on estimates and inferences.
- Yet, a part of the information is obtained through direct observations and analysis of materials.
- Direct sources of information include mining, deep drilling projects, and volcanic eruptions. Through these, we can directly analyze the materials from the interior of the earth. (Hence A is correct)
- Meteors are an indirect source of information as they are not directly from the interior of the earth. But the material and the structure observed in the meteors are similar to that of the earth. (Hence B is incorrect)
- Gravity anomalies give us information about the distribution of mass of the material in the crust of the earth. Uneven distribution of mass within the earth gives different gravity values. Thus it is also an indirect source. (Hence C is incorrect)
- Studying the seismic activity during earthquakes is one of the most important sources of information about the interior of the earth. Inferences about the density and depths of different layers of earth have been drawn using seismic studies. Thus it is also an indirect source. (Hence D is incorrect)
6.Which of the following not comes under diastrophism?
- Mountain building
- Warping of earth’s crust
- Minor movement of earth due to earthquake
- Formation of river valleys
Answer: D.
Explanation:
- All processes that move, elevate or build up portions of the earth’s crust come under diastrophism. They include:
- Orogenic processes involving mountain building. (Hence statement A is correct)
- Epeirogenic processes involving uplift or warping of large parts of the earth’s crust; (Hence statement B is correct)
- Earthquakes involving local relatively minor movements; (Hence statement C is correct)
- Plate tectonics involving horizontal movements of crustal plates.
- The formation of a river valley is a denudational process where the earth’s surface is eroded by water. (Hence statement D is incorrect)
- Soil creep is a slow movement of the soil along the slope under the influence of gravity. Although it is a slow process, it is not a diastrophic process as the source of energy is external.
7.Which of the following process is not associated with chemical weathering?
- Frost wedging
- Hydration
- Carbonation
- Reduction
Answer: A.
Explanation:
- Chemical weathering is a process in which rocks undergo decomposition, dissolution, or reduction to a fine clastic state through chemical reactions by oxygen, surface/soil water, and other acids.
- It operates through the processes of – solution, carbonation, hydration, oxidation, and reduction.
- Frost wedging is a physical weathering process that mainly occurs in glaciated areas.
- The growth of ice within pores and cracks of rocks during repeated cycles of freezing and melting widens the gaps in the rocks and eventually leads to their disintegration. (Thus option A is not a chemical weathering process)
8.Which of the following is not an erosional feature?
- Plunge pool
- Entrenched meander
- Unpaired terrace
- Natural levee
Answer: D.
Explanation:
- Plunge pools are large and deep potholes formed at the foot of waterfalls because of the sheer impact of water and rotation of boulders. Thus these are erosional features. (Hence option A is incorrect)
- When a meandering river cuts down the rocks symmetrically on both sides entrenched meanders are formed. Meandering is an erosional feature. (Hence option B is incorrect)
- River terraces are products of erosion marking old valley floor or floodplain levels. The river terraces that occur at the same elevation on either side of the rivers are called paired terraces. When a terrace is present only on one side or one at quite a different elevation on the other side, the terraces are called unpaired terraces. (Hence option C is incorrect)
- Natural levees are low, linear, and parallel ridges of coarse deposits found along the banks of large rivers. Often they are cut into individual mounds. (Hence option D is correct)
9.Which of the following are deep elongated troughs found at the heads of the glacial valleys?
- Horns
- Cirques
- Tarn lakes
- Fjords
Answer: B.
Explanation:
- Cirque are deep, long, and wide troughs with very steep walls found at the heads of glacial valleys. The accumulated ice cuts these cirques while moving down the mountain tops. (Hence option B is correct)
- A lake of water can be seen quite often within the cirques after the glacier disappears. Such lakes are called cirque or tarn lakes. (Hence option C is incorrect)
- Horns form through headward erosion of the cirque walls. If three or more radiating glaciers cut headward until their cirques meet, high, sharp-pointed, and steep-sided peaks called horns form. (Hence option A is incorrect)
- Very deep glacial troughs filled with seawater and making up shorelines (in high latitudes like Norway, Finland) are called fjords/fiords. (Hence option D is incorrect)
10.Which of the following statements about the endogenic processes is correct?
- Epeirogenic movements are a result of tangential forces.
- Orogenic movements are due to radial forces.
- Block mountains are a result of horizontal tensional forces working in opposite directions.
- Grabens and Horsts are formed due to compressional forces.
Answer: C.
Explanation:
- Epeirogenic movements are mainly associated with the formation of continents and plateaus. They are a result of radial forces originated from the earths’ interior and acting vertically. (Hence statement A is incorrect)
- Orogenic movements are associated with mountain building. They are a result of tangential (horizontal) forces acting on the earth’s crust. (Hence statement B is incorrect)
- Block mountains are formed when forces of tension work horizontally but in opposite directions. (Hence statement C is correct).
- Grabens and Horsts are the features of Block mountains that are formed due to tensional forces. (Hence statement D is incorrect).
- Syncline and Anticlines are formed due to compressional forces.