UPSC Geography Drainage Short Notes - Important Rivers of India

Important Rivers of India

Important River Valley Projects in India

Types of Natural Vegetation (Forest) in India.

Based on the predominant type of vegetation and climatic condition the forest type can be categorised into-

1. Tropical Evergreen and Semi Deciduous forest:

Predominant in western slope of western gnats, hills of north- eastern region and the Andaman and Nicobar island.

• These areas experience annual precipitation of 200 cm and mean annual temperature of these region is 22°C.
• Major species of these type of forests are rose wood, Mahigony ami,abony.

1. Tropical Deciduous Forest:

• These are the wide spread forests of India and also called as Monsoon forests.
• The rainfall requirement of these type of forests ranges between 70-200m. On the basis of rainfall availability these forests are further divided into moist and dry deciduous forests. The moist deciduous forests receive recorded rainfall of 100-200 cm and mostly found in the north eastern state, along the foothills of Himalayas, eastern slopes of Western Ghats and Odisha. On the other hand dry deciduous forest receive rainfall of 70 cm to 100 cm and found in the rainier areas of Peninsula and the plains of Uttar Pradesh and Bihar. One of the importand properties of these forests that the trees shed leaves during dry season.
• Major species of moist deciduous forest are teak, sal, shisham, hurra, Mahua, amia, Semul, Kusum and sandal wood, etc.

Major species of dry deciduous forest are Tendu, Palas, Amaltas, Bel, Khair, Axlewood, etc.

1. Tropical Thorn Forest:

• They are found in the semi-arid regions ofsouthwest Punjab, Haryana, Rajasthan, Gujarat, Madhya Pradesh and Uttar Pradesh.

These areas receives seasonal rain fall of 2 5 cm to 50 cm.

• The plant species of these kind of forests are date, Palm, Khair, Neem, Khejri, Palas, etc. The height of the plants in these areas are not more than 2 m.

1. Montane forest:

These type of forest are predominant in the higher altitude where there is decrease in Temperature. These can be subdivided into 3 categories:

(i)  Wet Temperate Forest

(ii) Temperate forest

(iii) Alpine forest

(i)       Wet Temperate Forest:

• They are generally found at an altitude of 1800 to 3000 cm above sea level and generally experience a rainfall 150 cm to 300 cm. The mean annual temperature required is 11° to 14° C.
• They have mainly occupied, high hills of Tamil Nadu and Kerala, Eastern Himalayan Region including hills of West Bengal, Assam, Arunachal

Pradesh, Sikkim, Nagaland.

• Important plant species are Deodar, Chilauni, Indian chestnut, Birch, Plum, Cinnamomum, Listea, Mongolia, Blue Pine, Oak, Hemlock, etc.

(ii)       Himalayan Moist Temperature Forest:

• They are found at an altitude of 1500 m to 3300 m. They receives 150 cm to 250 cm of rainfall.
• They occupy the areas such as Kashmir, Himachal    Pradesh, Uttaranchal, Darjeeling and Sikkim.
• Important plant species of these forests are pines, Cedars, silver.

(iii)      Alpine Forest Himalayan Dry Temperates:

(a) These forest grows in the areas where the south-west monsoon are weak and the precipitation is less than 100 cm.

(b) They grow in the inner dry ranges of Himalaya such as Ladakh, Lahut, Chamba, Kinnaur, Garhwal, and Sikkim.

1. Littoral & Swamp Forest:

They are further divided into:

             (a) Beach forest

             (b) Tidal forest or Mangrove forest

             (c) Fresh Water Swamp.

(a)        Beach forest

(i) It requires 75 cm to 500 cm of rainfall.

(ii)Generally found in sea beaches and river delta.

(iii) Important plant species are callophylum littoralis Pandanus, Thespesia, Barringtonia, Pongamia, cocos Mucifera, Spinzfix littoreus etc.

• Tidal or Mangrove Forest
• These are mainly found on both east and west sea coast of India and the soil of these forest is formed of silt, Silt-loam, silt clay and sand.
• Sundari tree is the famous plant species of this region. Other than this Palm, Coconut, Keora, Agar are also grown in some parts of this delta.

(c)        Fresh Water Swamp:

• Primarily occupied the area where rain or swollen river water is collected for sometime.
• Important plant species are solia tetrasperma, Acer,    Putrajiva, Holoptdia, Cepha lanthus, Borring tonia, Olea, phoeba, Ficus, Murraya, Adhatoda, and canna.

Features of Sunderbans

• State: West Bengal
• Area.-9630sq.km
• Endemic flora: Sundari, passur, Nypa
• Endemic fauna: Bengal tiger, Bengal monitor lizard, Salvator lizard.
• The main threat includes excess fishing, aquaculture practices and harvesting of timber and firewood.

Climate of India

• India has 'Tropical Monsoon' type of climate.
• The word monsoon has been derived from the Arabic word 'Mausam' which means seasonal reversal of the winds during the course of the year.
• The whole of India has a tropical monsoonal climate.
• Alternating seasons is the chief characteristic of India's climate.

Factors Affecting the Climate of India

Latitude (8°(r N and 37°0' N latitudes), Himalaya Mountains, Altitude, Distance from the sea.

• Western disturbances are responsible for the winter rain in Northern India.
• Air currents in the upper layers of the atmosphere known as jet steams could determine the arrival of the monsoons and departure of the monsoons.