Practically nothing has been done so far to assess the seriousness of this calamity in India, where her vast expanse of lands, cultivated since the pre-historic times and with conspicuous topographic variations under a variety of climatic regimes, are characterised by tremendous loss I of soil.
In the steep slopes of the Himalayan Siwaliks, Western Ghats, Nilgiris, as also in Assail | hills, wanton destruction of forest cover and reckless grazing for unlimited time have invite serious erosion, giving rise to networks of yawning ravines and gaping gullies which are continual; cutting back through the fertile agricultural lands.
Even the moderately sloping cultivated fields the Deccan tableland, Eastern Ghats, Aravali and the Chota Nagpur Plateau, experience tremendous losses in soil, rightly attributed to ever-grazing and uncontrolled deforestation in the higher slopes and catchment basins. Sheet washing in an extensive scale is going on unnoticed ii the whole of upper Gangetic plains.
Soil losses in colossal scale in Central Indian highlands and in humid sub-Himalayan hills of eastern India, are reflected in the stupendous silting of the river beds and low lands in the lower reaches of the Ganges and Brahmaputra, where mounting of flood heights with occasional floods, frequent change of river courses, total impedance of drainage systems giving rise to swamps, marshes and malaria, are some of the perennial menaces to inhabitants. No province other than West Bengal suffers more seriously from the aftermath of® soil erosion. In West Bengal, due to uncontrolled grazing, and unchecked burning and cutting down of forest cover in the Himalayas, especially in Sikkim and Bhutan Hills, soil erosion and soil creeps are rampant near the lower foothills. In North West Bengal, the silting of all the riverbeds, the diversion of river courses with rising flood heights and frequent submergence of low-lying riverine tracts with damage to crops, all may be rightly attributed to the same erosion of soils in the upper hills.
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The western fringes of West Bengal, just adjoining the Chota Nagpur Plateau suffer from serious gully erosion. The silting up of the rivers of Western Bengal with frequent violent floods, submerging vast extent of croplands are too well-known facts, especially in the case of the notorious Damodar River.
While East Bengal does not suffer from the danger of silting up of rivers and impedance of drainage, Central Bengal excepting the active deltaic land around the mouth of Padma and Meghan, represent a land of dying rivers, characterised by clogged river beds, marshy lands, dense jungles and malaria.
In short, almost the whole of West Bengal suffers from the ravages of soil erosion in one form or another, consequent upon the indiscreet tampering with the natural cover in the hills and basins beyond the area.
In the Siwalik Hills of Western Himalayas, high aridity coupled with denudation of the natural cover of forests and pastures, has induced continual invasion of vast expanse of fertile fields at the foot hills by a thick cover of erosional debris or ‘chos’, which is always tending to transform the landscape into a desolate and dreary waste.
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In fact, evidences of over-grazing, gully and ravine erosion can be noticed on the banks of almost every river and stream of India. In the West-Central India around the Sind-Rajputana deserts, progressive desiccation, together with the denudation of vegetative cover has induced terrific wind erosion, constantly threatening the smiling agricultural fields of the west.
The infertile ‘blur’ lands of U.P. are examples of blown sands. In each case, in addition to the loss of the fertile top soil, there is a marked fall in the water table, decrease in the sub soil supply of river water in cold sessions, thus putting the irrigation facilities and hydroelectric developments in a precarious position.
A detailed erosion survey over the length and breadth of India, conducted with the help of trained geographers, conversant with the climatography and physiographic of the land, will surely reveal facts and figures much more staggering than could be expected now.