Salinity Intrusion and Seasonal Water Quality Variations in the Tidal ...

which once served the purpose of modem roads, cannot be left to decline and decay as
water is growing more precious and dear in Cochin and elsewhere.
The domestic sewage from Cochin and its satellite towns ends up in the tidal
canals and the estuary. Cochin City alone generates 2550 million Uday ofurban sewage
that directly enters the estuary. In Cochin, the sewage treatment plant covers only 1 % of
the population (KSPCB, 1982). It is estimated that nearly 260 million liters of trade
effluents reach the Periyar estuary from the industrial belt daily. This discharge is fraught
with heavy metals, nutrients and insecticides (Venugopal, 1982). Cochin Back water
system, the largest of its kind on the west coast (256 knr'), receives 260t/day of organic
wastes fromthe16 major industries (Balachandran, 2001)
2.4 Population growth ofCochin and urbanization
In Kerala the rural-urban divide is not that sharp as far as basic amenities are
concerned and hence there is not an appreciable flux ofhumanity into the city. In 1875,
the population of Emakulam town was 20,000. From 1875 to 1901, the demography
remained more or less stalled. From the turn of 20 th century an explosive growth of
population was observed (Figure 2.4). This tendency persisted up to 1961 when the
population reached 2, 50,000 (Benjamin, 1998). In 1981, the population in the
corporation area was 5, 13,249 with a density of5400/.km 2 • In 1991, it reached 5, 64,000
and 5950 respectively. Census of 2001 shows that the total population of Cochin
Corporation is 5, 96,473, and the population of GCDA area is around two million. A
remarkable shoot up in population is expected in the years to come as the city is spreading
itself thin to the east, transgressing the city limits. A floating population of around
39