Environmental Degradation of the Coimbatore Wetlands in the Noyyal River Basin
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Environmental Degradation of the Coimbatore Wetlands in the Noyyal River Basin A. Pragatheesh 2013 EIA Resource and Pushp Jain Response Centre (ERC) Kotagiri, Nilgiri, India. During 8th and 9th centuries 30 wetlands were constructed on both sides of the River Noyyal for irrigation and flood mitigation. All these wetlands are interconnected to each other and with the River Noyyal. Over the years these wetlands have played an important part in development of human history and environment in the region. Coimbatore District Epigraphs Environmental Degradation of the Coimbatore Wetlands in the Noyyal River Basin A.Pragatheesh Pushp Jain EIA Resource and Response Centre (ERC) Nilgiri Unit Kotagiri, Tamil Nadu, India 2013 © EIA Resource and Response Centre (ERC) Citation – Pragatheesh, A; Pushp Jain (2013) Environmental Degradation of the Coimbatore Wetlands in the Noyyal River Basin, EIA Resource and Response Centre (ERC), Nilgiri, Tamil Nadu, India Quoting the Report : The report can be freely used with due credit. Published by - Legal Initiative for Forest and Environment (LIFE) N 71, LGF, Greater Kailash 1, Delhi 110048, India Contents Page 1. The River Noyyal 1 2. The Coimbatore Wetlands – History 2 3. Importance of Wetlands 3 Flood Control 3 Groundwater Recharge 3 Water purification and Nutrient Retention 4 Biodiversity (Plants and Animals) 4 Aesthetic and Recreation Value 5 Wetland Products and Local Employment 5 4. Threats to Wetlands 6 5. Coimbatore Wetlands 7 6. Fading glory of the Coimbatore Wetlands 8 Shrinking Wetlands 8 Poor Drainage 9 Waste Dumping 9 Encroachment 10 Water Pollution 11 Heavy Metal Pollution 12 Depletion of Ground Water 12 Decline in Agriculture 12 Contamination of Groundwater 12 Weed Growth and Eutrophication 13 Destruction of Avian Habitat 13 Poaching 14 7. Violations of the Wetland (Conservation and Management) Rules, 2010 16 8. Suggestions and Recommendations 21 9. Action Plan 23 10. Conclusion 24 References 25 Annexure : Profile of All the 24 Coimbatore Wetlands 26 Annexure : The Wetland (Conservation and Management) Rules, 2010 50 The River Noyyal The Noyyal or Noi il river, which translates into "devoid of illness" in Tamil, holds special significance for the Hindus (The Hindu, 2003). The River Noyyal is a prominent and historical feature of Coimbatore and the surrounding districts of Erode and Tirupur of Tamil Nadu State of India. It is considered as a divine and holy river which arising from the Vellingiri hills of the Western Ghats. In Coimbatore district the river gains its first sure footing before flowing into the other districts. Aandi Sunai from Vellingiri hills, Siruvani Water from Porathi hills and Chinnaru water from Kodungarai Pallam, water form Orathi falls and Ayyasamy falls are the main sources of water of this river. The River Noyyal is a tributary of the river Cauvery (a large inter-state river which flows through the States of Karnataka and Tamil Nadu) joining it at the Noyyal village, in Erode district of Tamil Nadu. The Noyyal is a seasonal river, rain fed by the North-East and the South-West monsoons. Occasionally, flash floods occur after heavy rain events. The upper reaches of the basin receives high rainfall of more than 3000 mm annually, while the eastern part receives only 600 mm. The pre-monsoon season period produces about 100 mm to 300 mm of rain and most of it is received during the months of April and May. The total length of the river is about 170 km, flowing from west to east, the total catchment area is 3510 km2 (Figure) and is located between 10°56’ N, 76°41’E and 11°19’ N, 77°56’E. The basin is widest in the central part, having a width of 35 km. The average width is about 25 km. The Noyyal forms the southern boundary of the Coimbatore city and acts as a major drainage course carrying the storm water discharge. Artificial lakes located in and around the city are unique systems of storm drainage, interconnected, designed and maintained from hundreds of years ago. Most of these lakes are located in southern part of the city that drains finally into the Noyyal River. These lakes are crucial for drinking water and agriculture of the region. However, in the recent times, despite cultivation being carried out in some parts, the lakes have been encroached upon heavily, both in terms of physical space and biological functioning. Figure: Noyyal River Basin (Source. WRO, PWD, Coimbatore) 1 The Coimbatore Wetlands – History Historical reference to the city of Coimbatore dates back to 1200 AD. Ruled by Cheran rulers, the city was developed as a strategic town during the Nayakas rule of Madurai. Tippu Sultan conceded the town to the British colonialists in 1799, who subsequently promoted Coimbatore as the military transit town between Palghat in the west and Gazal Hatty in the north. Beginning 1879, the city has started to emerge as an administrative and industrial town in its own merit. Wetlands are regularly been linked with the culture and heritage of the land usually a relic of interaction between people and landscape over centuries. Religious, spiritual and historical values are often interwoven with these wetlands. Ancient Tamil rulers have been known for their skills and technology in augmenting irrigation needs by constructing canals and waterways. The wetlands (locally called kulams) we now see in the Coimbatore city are the brainchild of the Tamil kings who developed it hundreds of years ago for irrigation, flood control and for recharging ground water. During the Kongu Chola’s regime in 8th and 9th centuries there were 30 wetlands constructed on both sides of the River Noyyal for irrigation and floods mitigation. All these wetlands are interconnected to each other and with the River Noyyal (Coimbatore District Epigraphs Vol.1). Over the years these wetlands have played an important part in development of human history and environment in the region. Many historical remnants such as Roman coins and other antiques unearthed along the bank of the river corroborates to the fact that this civilization had trade links with the Romans. The nature of the river to get flooded downstream near the Noyyal village and otherwise scanty rainfall typical of this region caused the Chola kings to create an ingenious system of lakes and anicuts festooning the course of the river to not only contain and channelize the fury of the monsoon but also to aid the recharge of groundwater. The lakes are well connected and helped improve the agricultural wealth of this region. About 20,000 acre of agricultural land was directly irrigated through this system. These interconnected lakes, their canals and rivulets also formed an active flood buffer for the river. Over the period of time, these wetlands came to house a lot many species of birds, fish and other life forms in pristine glory. 2 Importance of Wetlands The cultural and biological diversity of wetlands together represent a natural wealth that sustains us both physically and emotionally. The value of the world’s wetlands is increasingly receiving due attention as they contribute to a healthy environment in many ways (Paul et al. 2011). It is common knowledge that Wetlands provide a range of ecosystem services, most vital of which is water security to the region and its inhabitants. Urban wetlands act as haven for many species of flora and fauna, stabilise the local climate, help in flood control and replenish groundwater and it is important for carbon sequestration and emissions. Wetlands protect and regulate the water resource. Acting like giant sponges, they hold back water during floods and release it during dry periods. It is very crucial for country like India. By regulating water flows during floods, wetlands reduce flood damage and help prevent soil erosion. Wetlands recharge ground water sources, and also remove pollutants from the water. Being natural filters, they help to purify water by trapping many pollutants, including sediment, and disease causing organisms. Wetlands serves multiple function, some of which are listed below. Flood Control Almost any wetland can provide some measure of flood protection by holding the excess runoff after a storm, and then releasing it slowly. The size, shape, location, and soil type of a wetland determine its capacity to reduce local and downstream flooding. While wetlands cannot prevent flooding, they do lower flood peaks by temporarily holding water and by slowing the water's velocity. Wetland soil acts as a sponge, holding much more water than other soil types. Even isolated wetlands can reduce local flooding if the wetlands were not there to hold storm water runoff, backyards and basements might end up under water. Wetland vegetation can bind the shoreline together and reduce erosion from storms. Coimbatore has a natural topography, sloping from North towards South and West towards East. The slope benefits storm water run-off and the path of natural drains facilitate draining of storm water. The Noyyal river acts as a major drainage course carrying the storm water discharge through the lakes that finally drain into the Noyyal river. Among the many drains, the Sanganur Pallam (Canal) is the main drainage artery, which traverses from north to south with its outfall in the Noyyal river. Groundwater Recharge Wetlands act like nature’s sponges, soaking up rainfall that then filters into the ground acting as groundwater recharge areas when the water table is low, and as groundwater discharge zones when the water table is high. During periods of low stream flow, the slow discharge of groundwater often helps maintain minimum water levels. Wetlands are directly connected to groundwater and play a vital role in regulating the quantity and quality of groundwater, which is often an important source of water for drinking and irrigation of crops.