Eco-Hydrology and Chemical Pollution of Western Ghats
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Eco-hydrology and Chemical Pollution of Western Ghats Dr.Mathew Koshy M..Sc., M.Phil., Ph.D. Reader and Research Guide in Chemistry, Bishop Moore College, Mavelikara.Kerala Eco-hydrology Eco-hydrology is a new integrative science that involves finding solutions to issues surrounding water, people, and the environment. One of the fundamental concepts involved in eco-hydrology is that the timing and availability of freshwater is intimately linked to ecosystem processes, and the goods and services provided by fresh waters to societies. This means that emphasis is placed on the hydrological cycle and its effects on ecological processes and human well-being. Limnology Limnology is the science that deals with the physical, chemical and biological properties and features of fresh waters. A professional who studies fresh water systems is a limnologist. Lotic System: The lotic environment is consisting of all inland waters in which entire water body continually flows in a definite direction. etc. rivers streams. Lentic system: The lentic environment has been including all inland waters in which water has been not continually flowing in a definite direction. Standing waters Western Ghats The Western Ghats hill range extends along the west coast of India, covering an area of 160,000 square kilometers. The presence of these hills creates major precipitation gradients that strongly influence regional climate, hydrology and the distribution of vegetation types and endemic plants. Biodiversity Although the total area is less than 6 percent of the land area of India, the Western Ghats contains more than 30 percent of all plant, fish, fauna, bird, and mammal species found in India. The region also has a spectacular assemblage of large mammals and is home to several nationally significant wildlife sanctuaries, tiger reserves, and national parks. A total of 58 protected areas consisting of 14 National Parks and 44 Wildlife Sanctuaries fall within its 1 boundaries. The total area covered by these protected areas is 13,595 sq km representing 9.06 percent of the Western Ghats . It is one of two biogeographic zones (the other being the Andaman and Nicobar Islands) with the highest level of coverage by protected areas in India. The Western Ghats contains numerous medicinal plants and important genetic resources such as the wild relatives of grains (rice, barley, Eleucine coracana), fruits (mango, garcinias, banana, jackfruit), and spices (black pepper, cinnamon, cardamom, and nutmeg). Biodiversity in the Western Ghats is threatened by a variety of human pressures. Only one third of the area is under natural vegetation.. Three hundred and forty species of vertebrates (36% of all vertebrate species) are endemic to the Western Ghats. Amongst amphibians, 94 of the 121 species (78%) known till date from the ecoregion are endemic. Rainfall On account of its mountainous topography and heavy rainfall (between 2000 and 8000 millimeters of annual rainfall within a short span of 3-4 months), the Western Ghats performs important hydrological and watershed functions. The soils and waters of this region sustain the livelihoods of millions of people. Pesticides Estimates suggest that around 4,00,000 ha is under tea cultivation in India. While Assam and West Bengal top the list amongst the Indian states, in the Western Ghats, Kerala, Tamil Nadu and Karnataka are the primary cultivators of tea; together they cultivate 73,669 ha amounting to 18% of the country’s tea gardens. In the Western Ghats, tea grows between elevations of 300 and 2300 m ASL and within rainfall regimes of 90–750 cm per annum, coinciding with the biodiversity-rich rainforests and the endemic montane shola-grassland ecosystems.Since tea grows best in the humid, biodiversity-rich parts of the world, it has attracted a large number of pests. The literature states that over 300 species of arthropods, 58 species of fungi and 130 species of plants infest tea cultivation in India alone, necessitating the continuous application of heavy doses of pesticides. And, despite the international markets’ concern on the human health hazards posed by the toxic residues in tea, not less than 30 different pesticides are used. Pesticides commonly used on tea Organochlorine compounds Dicofol , Endosulfan Organophosphorous compounds Ethion , Quinalphos , Chlorpyrifos Synthetic pyrethroids Deltamethrin Weedicides Paraquat , Glyphosate Fungicides Copper oxychloride Recent studies have shown that insecticides such as DDT, dieldrin and malathion affect the immune systems, and the herbicide atrazine, at such small doses as 0.1 parts per billion, causes reversal of sex in amphibians. Ironically however, the permitted residue of atrazine in processed tea is 0.1 parts per million32 – 1000 timeshigher than what is safe for an amphibian! While atrazine, DDT and dieldrin are not among the pesticides recommended for tea, malathion is occasionally used to control green fly, a sucking pest of minor importance in tea. Breakdown of immune systems in amphibians can make them vulnerable to diseases. 2 What happens to the pesticides used in tea cultivation? The heavy rainfall (450 cm per year) might just wash most pesticides from exposed surfaces. The chemicals will contaminate aquatic system. Water is life and is necessary for all ecosystems. The chemically contaminated water may poison the ecosystem. Many of the rivers are originating from western ghats and chemically contaminated water pose serious threats living systems. Let us look into the rivers originating from western ghats. Western Ghats rivers Krishna rises in the Western Ghats, at an altitude of 1,336 metres near Mahabaleshwar in Maharashtra, flows from west to east for a length of about 1,400 km, through Maharashtra, Karnataka and Andhra Pradesh. The Krishna has a drainage area of about 2.59 lakh sq km. Together with its tributaries, it flows for about 704 km length in the State. Ghataprabha The Ghataprabha river rises in the Western Ghats, at an altitude of S84 metres and tlows eastwards for a length of 283 km before joining the Krishna. The river debouches by 53 metres at Gokak Falls in Belgaum Dt. The total catchment area of the river and its tributaries accounts for 8,829 sq.km in Maharashtra and Karna,taka States. Malaprabha also rises in Western Ghats at an altitude of 792 metres in Belgaum Dt. The river flows first in easterly and then in north-easterly directions and joins the Krishna at Kudalasangama, about 304 km from its source. The principal tributaries are the Bennihalla, Hirehalla and the Tas Nadi. The total catchment area of the Malaprabha and its tributaries is 11,549 sq km., wholly in Karnataka. Bhima river also rises in Western Ghats, at an altitude of about 945 metres and flows south- east wards through Maharashtra and Karnataka. It flows for 861 km before joining the Krishna near Kudlu in Raichur taluk. The latter 298 km of the Bhima's course is in the State. It has a drainage area of 70,614 sq km out of which 18,315 sq km lies in Karnataka. Tungabhadra formed north of Shimoga at an elevation of about 610metres by the union of twin rivers, the Tunga and the Bhadra, which rise together in the Western Ghats at an elevation of about 1,198 metres. The Varada and the Hagari are its important tributaries. It has a drainage area of 71,417 sq.km out of which 57,671 sq.km lies in the State. It flows for a distance of 293 km. in the State. Cauvery has its origin in the Western Ghats in Kodagu Dt. It flows for a length of 320 km in the State. The river flows generally in a south-east direction. The Chunchanakatte Falls (about 20 m) and the Shivasumdra Falls (about 100 m) exist in the State. Hemavat rises in the Western Ghats at an elevation of about 1,219 metres and joins the river Cauvery near Krishnarajasagar. The drainage area is about 5,410 sq.km and the approximate length of the river is 245 km. Kabini The river Kabini has a total course of about 230 km and a catchment area of about 7,040 sq.km. It joins the Cauvery river at Tirumakudal Narasipur. 3 Godavari basin Godavari basin has a drainage area of 4,405 sq.km. Only a small part of Godavari basin lies in the State. The river Manjra is the major tributary of the Godavari and it flows for about 155 km in the State. Pennar and Palar basins The North Pennar, South Pennar and the Palar rivers drain about 13,610 sq.km in the State. The Mahe river, also called the Mayyazhi puzha, originates from the forests on the western slopes of the Wayanad hills which from part of the Western Ghats. The length of the river is about 54 kms. and it flows through an area of 394 sq. kms. The Murad river, also known as the Kuttiady river, takes its origin from the Narikota ranges on the western slops of the Wayanad hills, a part of Western Ghats. This river has a length of 74 kms. and along with its tributaries it flows through an area of 583 sq. kms. The Onipuzha, the Thottilpalam puzha, the Kadiyangad puzha, the Vamathil puzha and the Madapalli puzha are the major tributaries of Murad river. It passes through Oorakuchi, Kuttiady, Tiruvallur, Muyipoth, Maniyur and Karuvancheri. The Korapuzha formed by the confluence of two streams called Punnurpuzha and Agalapuzha, this river and its main tributaries are tidal in their lower reaches. The Agalapuzha is more or less a backwater, while the Punnurpuzha originates from Arikkankunnu. The Agalapuzha forms a part of the important. West Coast Inland Navigation System. The total length of the river is 40 kms. with a drainage area of 624 sq. kms. The Kallai river has its origin from Cherukulathur village and is connected to the Chaliyar on the south by a man-made canal.