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

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5.3.3 Canals having fresh water for most part of the year and not much
polluted.
Kadambrayar, Chithrappuzha, Karingachirapuzha and Panar belong to this group.
Canals ofthis category are already used as a fresh water source by industries, local water
supply schemes (e.g., Mulamthuruthy) and farm lands. Annual bund building on these
water courses arrests the possibility of salinity intrusion. But canals have a sizable and
predominantly agricultural basin, resulting in substantial residual flow. These canals are
already playing a significant role in the local economy in the capacity as a fresh water
source and by facilitating large-scale navigation. As far as Chithrapuzha-Kadambrayar
basins are concerned, industrial discharges cause a serious threat to the quality of water.
The organic fertilizer industry on the Kadambrayar takes a serious toll on DO and
apparently adds to COD and BOO. The water theme park is also allegedly influencing
negatively on the quality of water. The huge Gypsum mount accumulated over the years
close to Chithrapuzha deteriorates the clarity of water after every washout following a
serious rain. The municipal discharge into Andhakaran thod ultimately influences the
quality of Karingachira puzha. Fugitive dumping of organic wastes from the bridges has
seriously affected the quality of water at Kaniyavally, Kandanad and Kolenchery, If
some more managerial energy is put into the maintenance of these canals, they would
function as excellent sources offresh water
5.3.4 Fresh water bodies heavily polluted
There are only two canals under this head -Adimury thod and western half of
Edappally thod. Water from these canals was once extensively used for irrigation. If the
domestic sanitary discharges are subjected to treatment before discharging into Adimury
thod, it can still be reclaimed as a year-round fresh water source, suitable for irrigation,
washing and flushing. Good maintenance of this natural stream is of vital importance as
the low-lying chunk of land behind the international stadium is flood-prone. Fortunately,
the western half of Edappally thod is not in a thoroughly urbanized region. Hence
sewage insult is not much beyond its self purification capacity. But the slaughterhouses
in this area find it expedient to get rid of the daily waste into this canal. If the canal is
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