WBBSE Madhyamik Geography key terms

The slow breaking down or dissolving of rocks and minerals where they lie, caused by water, ice, wind, heat, cold, and living things, without any movement of the broken material.

The wearing away and removal of rock or soil by moving agents such as running water, wind, waves, or ice, which then carry the loosened material to another place.

The laying down of eroded material such as sand, silt, or gravel when the carrying agent loses energy, for example where a river slows on entering a plain or the sea.

A fan-shaped area of new land built at a river mouth where the current slows and deposits fine sediment, often branching into several distributary channels, as in the Ganga-Brahmaputra delta.

Fine, fertile sediment of sand, silt, and clay carried and laid down by rivers on their floodplains and deltas; it forms the basis of agriculture across the northern plains of India and southern West Bengal.

A branch channel that leaves the main river and carries water away from it, common near deltas where sediment blocks the main course and splits the flow into several outlets.

A smaller river or stream that joins a larger one and adds its water to it, such as the Damodar joining the Hooghly system, usually raising the main river's volume downstream.

The whole area of land drained by one river and all its tributaries, bounded by higher ground called divides, so that all rain falling inside it eventually reaches the same river mouth.

The boundary line of high land separating two neighbouring drainage basins, so that rainfall on one side flows into one river system and rainfall on the other side flows elsewhere.

A seasonal reversal of prevailing winds, most strongly seen in South Asia, where moist winds blow from the sea in summer bringing heavy rain and dry winds blow from land in winter.

A dry region on the side of a mountain range facing away from the prevailing rain-bearing wind, because the air has already lost its moisture while rising over the opposite slope.

Rain caused when moist air is forced to rise over hills or mountains, cools, and condenses; heavy rain falls on the windward slope while the leeward side stays drier.

An intense low-pressure storm that forms over warm tropical seas, with strong spiralling winds and heavy rain, and which often strikes the Odisha and West Bengal coast in autumn.

An abnormal rise of sea level near a coast, pushed ashore by the strong winds and low pressure of a cyclone, which causes severe flooding in low-lying delta areas.

A vertical section through soil from the surface down to the underlying rock, showing distinct layers or horizons that differ in colour, texture, and organic content.

The washing down of soluble minerals and nutrients from the upper soil layers by heavy rainfall, which can leave soils acidic and less fertile, as in parts of the laterite regions.

A reddish, iron-rich soil formed in hot, wet climates where heavy leaching removes silica and leaves iron and aluminium oxides behind; it hardens on exposure and is poor for most crops.

The tract of land lying between two rivers that flow roughly parallel before joining, a term widely used in the Ganga-Yamuna plain and also applied to similar interfluves in West Bengal.

The flat land beside a river that is built up of sediment and is covered by water during floods; it is usually fertile and densely farmed, as along the Ganga and Hooghly.

A belt of marshy, forested land at the foot of the Himalaya, just south of the hills, where streams spread and the water table is high; it runs across northern West Bengal and neighbouring states.

The narrow, low-lying passage-like plains at the southern foot of the eastern Himalaya in northern West Bengal, known for tea gardens and swift streams coming down from Bhutan.

A block of ancient, hard rock covering much of Jharkhand and extending into western West Bengal, rich in minerals such as coal and iron ore and drained by the Damodar and Subarnarekha.

The western, older, and relatively higher part of West Bengal lying between the Chotanagpur Plateau and the Bhagirathi-Hooghly, with red-brown soil, undulating land, and the Damodar flowing through it.

The valley of the Damodar river in eastern India, known for coal, industry, and a chain of multipurpose dams and barrages built to control floods and supply power and irrigation.

The vast tidal mangrove forest and swampy delta at the mouth of the Ganga-Brahmaputra, shared by India and Bangladesh, home to the Royal Bengal tiger and protected as a biosphere reserve.

A region with an unusually high number of species found nowhere else and a serious loss of natural habitat; the eastern Himalaya and the Indo-Burma region include parts of India.

A large river scheme built to serve several aims at once, such as flood control, irrigation, drinking water, hydroelectric power, navigation, and fish farming, usually through dams and canals.

The supply of water to farmland through man-made channels drawn from a river or reservoir, allowing cultivation in areas that receive too little or too irregular rainfall.

Water stored in the pores and cracks of rock and soil below the surface, reached by wells and tube wells and widely used for irrigation in the plains of West Bengal.

The upper level of the saturated zone underground, below which all openings in soil and rock are filled with water; it rises in the rainy season and falls in the dry months.

A large estate where tea bushes are grown and the leaves processed on site; it needs well-drained slopes, plentiful rain, and cool misty conditions, as in Darjeeling and the Duars.

The manufacture of sacks, bags, and yarn from jute fibre, historically concentrated along the Hooghly near Kolkata because the raw fibre grows in the surrounding delta and river water is available.

The set of factors that decide where a factory is built, such as raw materials, power, transport, labour, market, capital, and government policy, whose relative importance changes over time.

The ratio between a distance on a map and the same distance on the ground, shown as a statement, a representative fraction, or a graduated bar, allowing real distances to be measured.

A line on a map joining points of equal height above sea level; where contours are close together the slope is steep, and where they are far apart the land is gentle.

A small number printed on a map at a particular point to show its exact height above mean sea level, helping to read the relief of the land where contours are absent.

A set of numbers read from the easting and northing lines of a map's grid, giving the position of a feature; the easting is always read before the northing.