Daily Quiz #11 UPSC Prelims Marathon – July 12, 2019

Explanation: The Indus System: It is one of the largest river basins of the world, covering an area of 11,65,000 sq. km (in India it is 321, 289 sq. km and a total length of 2,880 km (in India 1,114 km). The Indus also known as the Sindhu, is the westernmost of the Himalayan rivers in India. The river flows southward and receives ‘Panjnad’ a little above Mithankot. The Panjnad is the name given to the five rivers of Punjab, namely the Satluj, the Beas, the Ravi, the Chenab and the Jhelum. It finally discharges into the Arabian Sea, east of Karachi. The Indus flows in India only through Jammu and Kashmir.
The Jhelum, an important tributary of the Indus, rises from a spring at Verinag situated at the foot of the Pir Panjal in the south-eastern part of the valley of Kashmir. It flows through Srinagar and the Wular lake before entering Pakistan through a deep narrow gorge. It joins the Chenab near Jhang in Pakistan.
The Chenab is the largest tributary of the Indus. It is formed by two streams, the Chandra and the Bhaga, which join at Tandi near Keylong in Himachal Pradesh. Hence, it is also known as Chandrabhaga. The river flows for 1,180 km before entering into Pakistan.
The Ravi is another important tributary of the Indus. It rises west of the Rohtang pass in the Kullu hills of Himachal Pradesh and flows through the Chamba valley of the state. Before entering Pakistan and joining the Chenab near Sarai Sidhu, it drains the area lying between the southeastern part of the Pir Panjal and the Dhauladhar ranges.
The Beas is another important tributary of the Indus, originating from the Beas Kund near the Rohtang Pass at an elevation of 4,000 m above the mean sea level. The river flows through the Kullu valley and forms gorges at Kati and Largi in the Dhaoladhar range. It enters the Punjab plains where it meets the Satluj near Harike.
The Satluj originates in the ‘Raksas tal’ near Mansarovar at an altitude of 4,555 m in Tibet where it is known as Langchen Khambab. It flows almost parallel to the Indus for about 400 km before entering India, and comes out of a gorge at Rupar. It passes through the Shipki La on the Himalayan ranges and enters the Punjab plains. It is an antecedent river. It is a very important tributary as it feeds the canal system of the Bhakra Nangal project.

Explanation: Monsoons refer to a system of winds in the tropical regions under which the direction of winds is reversed completely between the summer and the winter seasons. Under this system, the winds blow from land to sea in winter and from sea to land in summer. Therefore, most of the rainfall in the regions influenced by the monsoons is received in the summer season while winter season is generally dry.
As the vertical rays of the sun shift northwards over the Tropic of Cancer in summer season, the Inter-Tropical Convergence Zone(ITCZ) also shifts to north. This results in the formation of a low pressure area over the northwestern parts of India. This low pressure is further intensified by the high temperatures in this region. This low pressure area sucks the air from the Indian Ocean towards the Indian landmass in the form of Southwest monsoons. In winter season, the ITCZ shifts southwards and a mild high pressure is produced over northern parts of India. This high pressure is further intensified by the equator ward shift of the sub tropical high pressure belt. Due to high pressure over northern lndia, the winds start blowing from northeast as retreating monsoons. According to recent observations, the origin of Indian monsoon is influenced by a number of other factors, besides the differential heating of land and sea and the seasonal shifts of pressure and wind belts. One of the most important factors among these is the system of subtropical westerly and tropical easterly jet streams.
The peninsular shape of India divides these Southwest monsoons into two branches – Arabian Sea branch and Bay of Bengal branch.
(a) Arabian Sea branch of Southwest monsoons strikes the western coast of India and causes heavy rains on the western slopes of the Western Ghats. After crossing the Western Ghats, these winds cause less rainfall on the eastern slopes as they gain temperature while descending. This area is, therefore, known as rain shadow zone. This explains why interior parts of Maharashtra, Karnataka and Telangana get meagre rains from these winds. Southwest monsoons striking along the coast of Saurastra and Kuchchh and pass over Rajasthan and beyond to meet the Bay of Bengal branch. These winds cause widespread rain in these states and western Himalayan region. (b) The Bay of Bengal branch is divided into two sub branches after striking eastern Himalayas. One branch moves towards the east northeast direction and causes heavy rains in Brahmaputra valley and northeast hills of India. The other branch moves towards northwest along the Ganga valley and the Himalayan ranges causing heavy and widespread rains over vast areas. In this region, the amount of rainfall decreases from east to west owing to the progressive decrease in humidity of these winds.

Explanation: Social forestry means the management and protection of forests and afforestation on barren lands with the purpose of helping in the environmental, social and rural development. The National Commission on Agriculture (1976) has classified social forestry into three categories. These are Urban forestry, Rural forestry and Farm forestry.
•Urban forestry pertains to the raising and management of trees on public and privately owned lands in and around urban centres such as green belts, parks, roadside avenues, industrial and commercial green belts, etc.
•Rural forestry lays emphasis on promotion of agro-forestry and community-forestry.
Agro-forestry is the raising of trees and agriculture crops on the same land inclusive of the waste patches. It combines forestry with agriculture, thus, altering the simultaneous production of food, fodder, fuel, timber and fruit.
Community forestry involves the raising of trees on public or community land such as the village pasture and temple land, roadside, canal bank, strips along railway lines, and schools etc.
•Farm forestry is a term applied to the process under which farmers grow trees for commercial and non-commercial purposes on their farm lands. Forest departments of various states distribute seedlings of trees free of cost to small and medium farmers. Several lands such as the margins of agricultural fields, grasslands and pastures, land around homes and cow sheds may be used for raising trees under non-commercial farm forestry.

Explanation: Tropical thorn forests occur in the areas which receive rainfall less than 50 cm. These consist of a variety of grasses and shrubs. It includes semi-arid areas of south west Punjab,
Haryana, Rajasthan, Gujarat, Madhya Pradesh and Uttar Pradesh. In these forests, plants remain leafless for most part of the year and give an expression of scrub vegetation. Important species found are babool, ber, and wild date palm, khair, neem, khejri, palas, etc. Tussocky grass grows upto a height of 2 m as the under growth.