The Land of Goa. By Indian standards Goa is a tiny state. The coastline on which much of its fame depends is only 97 km long. The north and south of the state are separated by the two broad estuaries of the Zuari and Mandovi Rivers. Joined at high tide to create an island on which Panaji stands, these short rivers emerge from the high ranges of the Western Ghats less than 50 km from the coast and then glide almost imperceptibly to the sea. On either side of the rivers are extensive tidal marshes, and to north and south a series of minor streams run through flat bottomed valleys into the sea. From Tiracol in the north to Betul in the south these estuaries provided an important though far from wholly effective defence against intruders. Often overlooked by steep sided hillocks rising to the flat tops of the laterite plateaus which make up much of the area between the marshes, some of the estuaries contain the last remains of mangrove swamp and its associated ecosystem in western India.
The long sandy beaches which run for much of the length of both the north and the south coasts are backed by parallel sets of dunes. Apparently barren and economically useless the dunes have provided an important part of the wider ecosystem, providing shelter for housing and transport just inland. The beaches themselves are interrupted at various points by seaward extensions of the laterite plateaus which sometimes form impressive headlands. These provided ideal sites for coastal forts, as at Chapora, Fort Aguada or Cabo de Rama.
Inland from the coast Goa occupies a shallow indentation in the Sahyadri Ranges of the Western Ghats. Rising to around 1,000m along this section of their crest line, the Ghats were developed on the old fault which marked the separation of the Indian Peninsula from the ancient landmasses of Gondwanaland - which today have become South Africa, South America and Antarctica. Separated from that great continental land mass less than 100 million years ago, the Indian Peninsula has been pushing northwards ever since. At its northern margins as it thrust under the Tibetan Plateau it was responsible for the creation of the massive mountain wall of the Himalaya. That has caused huge instability along the northern margins of the Peninsula, wilh earthquakes frequent in the foothills of the Himalaya themselves. In contrast, the land on which Goa stands is largely stable.
Despite its stability, geologically Goa represents a transition point in the Ghats. To the north the often precipitous ridge is formed by volcanic lavas which poured out over the Indian Peninsula over 60 million years ago, laying the foundation today for the rich black soils that cover so much of the Deccan to the northeast of Goa. In contrast, from Goa southwards the ridge of the Ghats is formed from the ancient and hard rocks of the Indian Peninsula, granites and gneisses. However, the ridge of the Ghats has been pushed back much further from the coast in Goa than anywhere else, because its short but powerful streams have eaten into the catchment areas of the great rivers of the Peninsula. This process has given Goa the 'breathing space' which marks it out from the rest of the much narrower strip of lowlands between the Ghats and the sea to both north and south.
The slightly greater extent of its coastal lowlands has not given Goa much easier access to the interior. The hill ranges rise sharply from the coastal plains, creating a wholly distinct, remote and rugged environment and pierced only by narrow gorges which lead up onto the plateau. Minor seasonal streams cascade down the mountain sides in the monsoon, while at the 600m high Dudhsagar ('sea of milk') falls the River Candepar plunges in a series of dramatic leaps throughout the year. The forested slopes of the Ghats are relatively sparsely populated, forming a natural barrier between the coastal lowlands and the much more open landscape immediately across the ridge of the hills in neighbouring Karnataka.
Where the laterite plateaus reach the coast, as at Chapora in the north, Dabolim in the centre or Cabo da Rama in the south, they produce rocky headlands jutting out into the sea, ideal sites for the string of coastal forts with which both the Portuguese and the Marathas defended their maritime and landward interests. The estuaries formed near such headlands - at Tiracol or Fort Aguada, Chapora or Betul - all suggest that in recent times sea level has risen slightly to flood the lower courses of the streams at high tide, pushing salt water several kilometres inland.
While the sandy beaches of the coast have provided the basis for Goa's rapidly expanding tourist industry the land of the interior of Goa has also become a vital resource. Rich in iron ore and manganese, huge open cast mines have provided enormously important exports. While the income derived from this has helped to boost Goa's foreign exchange, it often scars the landscape of the interior and has had a much criticized effect on neighbouring agriculture.