The Ecological Tragedy Of River Sal - Part I

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THE Sal river is the Mississippi of Salcete taluka. Unfortunately there is no Mark Twain in Goa to sing the glories of its’ character. The Salcete taluka with about 300 sq kms area is intimately linked to the well being of its’ only river basin – the geologically special and ecologically fragile Sal river basin.

Sal is the third largest river (35 kms) in Goa with third largest basin (301 sq kms). Although its’ catchment area and runoff (700 million cubic metres per year) is one third of the Zuari river, it has not received even one third of attention which both Mandovi and Zuari rivers have received. This is a serious mistake by the planners considering the ecological tragedy of the river.

Land use and drainage management planning in Salcete is destined to fail if it fails to respect the river basin, the hydrography and ignores the eco-restoration of the heavily silted and polluted channel between Margao’s Khareband to Betul. Sal River is a geological and hydrological oddity. It runs parallel to the west coast geological fault. It is the only river that follows a North-South direction before meeting the Arabian Sea at Betul.

The river originates as a small stream (now under the danger of obliteration due to development) from the ancient site of Mahalsa temple on Verna hills. Originally it could have been known as Verna River. There is a tradition in India to build temples at the site of the sources of rivers. But despite its’ cultural importance, the Sal river was never treated as a sacred river.

On the contrary, rampant urbanisation, drastic land use change, reckless hill cutting, heavy agricultural runoff, encroachments, dumping of waste and relentless human interference over past 50 years have brought this river to an ecological tragedy. After traversing a distance of 10 kms, it becomes wider and at Verna four streams combine in the paddy fields between Arossim and Cansaulim to create the main channel of the Sal River.

Today this whole area has been transformed due to reckless land development endangering the feeder streams of the river. Till the river reaches Mugul, 12 more streams feed it. All these streams are getting heavily polluted and are in a very bad shape endangering the ecology of the river. After crossing Mugul Bridge, near the old court a small stream flowing from Agali near Holy Spirit church meets the river. Then the river crosses south central railway line near Damodar College. From here there is a westward turn, which takes the river to Khareband. From Khareband Sal River becomes an estuary.

People and their popular politicians have perhaps forgotten that only a century ago the Sal estuary was fully navigable upto Margao. All types of country crafts used to navigate between Margao to Betul. During the ancient period it had played a supplementary role in feeding commodities and transporting other goods and passengers in the hinterland and had linked Chandor – the old capital of Bhojas and Goa Kadambas through a network of small ports at Betul, Velim and Assolna. Two large streams or rivulets – the Navelim and Cuncolim join this estuary below Varca. Upto Varca village the river channel is narrow –about 40-50 metres but the tidal effect seems more pronounced after Varca village. The river channel is widened to 750 metres downstream of Varca. The journey of Sal estuary from Varca to Betul is complex and interesting. There is a definite human signature is steering its’ course to create vast fertile Khazan paddy fields, interior creeks and salt pans. This could have been possible due to heavy sediment load, which the primitive agricultural communities removed and deposited on higher ground to create new khazan lands.

There are 8 major and 6 minor estuarine islands in the river channel. The major islands are natural but are protected by man-made embankments. The Northeast bank of the river has 14 primary tributaries/creeks and 38 secondary tributaries/creeks. The Southwest bank has four each. The hydrography in the last 18 kms of the estuary’s journey shows a fine and intricate balance between land and water. There are 16 mini peninsulas. These are so fragile that higher tidal amplitude and sea level rise would cause their progressive erosion and elimination. That may widen the channel of the river and may even change the course.

Sal river flows on a flat plain – perhaps as flat as a sheet of paper and nowhere in its’ course from Khareband the channel experiences a higher ground. This flat river morphology makes the river basin extremely vulnerable to impact of sea level rise. The global sea level rise expected in a few decades would claim all the land from Salcete, which is on average a few metres above the present sea level. Between Velsao to Cavellosim on the Western-Southwestern bank of the river a belt of 500 metres to 2 kms width of Khazan paddy fields separates the river from the settlement areas.

Actually this is the original flood plain of the river later reclaimed by the local ‘gaunkaris /communidades’. The Velsao to Cavellosim settlement belt has no natural support or ecological security. The old sand dunes have been flattened. The mangroves have been disturbed near human settlements. So these settlements where a large number of mega projects and hotels have been built would be caught between rising Arabian Sea on the Western side and the floodwaters of Sal River on the Eastern side.

After 1979-80 very little attention was paid to the strengthening of the river embankments between Varca to Cavellosim. Velim gets flooded because of the heavy silt in Sal River and the erosion of the protective bundhs. People used to service and maintain the river for hundreds of years because they considered it as an economic lifeline. The rich silt produced bumper paddy harvests. The abundance of fish and shellfish in the river was a good supply of food and income.

Land use changes, sectoral labour shifts, massive urbanisation, industrialisation severely impacted the community services which had maintained the river. Without any alternatives people began using the Sal River as a dumping ground for their effluents, sewage and solid waste. Margao may have an underground sewerage system but it is the Sal River, which still drains Margao and its outskirts. Nutrient overloading of the river at several points has created bottlenecks. Aquatic weeds like water hyacinth, Pistchia and Salvinia were not seen in Sal River before 1980.

Today the river is overgrown and saturated with these weeds at several points. Such eutrophication is a clear sign of ecological tragedy. The entire Sal river basin urgently needs a massive eco-restoration project but the government has adopted only cosmetic approach for small stretches (to be continued).