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

early February in the case of Galaxy Apartments site. Thereafter, salinity
thins out and water becomes fresh again, by the first week of May in the
case of Galaxy and at AIMS towards the end of May. The tidal part is
saline from early October to mid May. When the water is fresh alkalinity
rises above total hardness and both are predominantly due to bicarbonates.
3.2.6 On Karingachirapuzha, tidal intrusion is potentially possible from either
end, but the northern end of the canal where it joins with Kaniyampuzha is
silted up preventing the exchange of water. Temporary bunds at
Swargavathil and Andhakaran thod substantially obliterate the seasonal tidal
influence. All segments of the canal are fresh up to early November.
Salinity peaks in the first week of January and then falls a little. Towards
the end of March, salinity reaches the maximum, measuring around 12000
mg/L at Andhakaran thod. At the sampling points of Andhakaran,
Kanjiramattom, Swargavathil down, and Poothotta, salinity crosses 5000
mg/L from November to mid March. But salinity hovers around 2000 mg/L
during the lean months at the sites of Karingachira, Kaniyavally, Kandanad,
Kolenchery, Mattathankadav and Swargavathil Up. Panar, a stream coming
from the east, is fresh throughout the year. Alkalinity is entirely due to
temporary hardness through out the year except for Karingachira site during
the advanced stages ofsalinity intrusion.
3.2.7 The tidal canals of West Cochin in toto are saline for most part of the
year. The utility of these canals as a fresh water source is apparently
doubtful. From early December to late April, chloride level is very close to
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