S. A. Abbasi, K. K. S. Bhatia, A. V. M. Kunhi and R. Soni
Abstract
A study of the water quality, flora, fauna, and their interrelationships in the Kuttiadi lake, which is a man- made water body situated in North Kerala, India, is presented. The variables were studied at three representative sites : Dam (station 1), Allerymuzhi (station 2) and Kallanode (station 3), of widely varying depths. The findings were compared with the water quality standards for drinking, irrigation and aquatic life set by various national and international agencies. It was seen that the water quality of the lake falls short of the acceptable levels at certain depths and times of the year, especially so in the months (October onwards) following the monsoon. The Kuttiadi lake becomes thermally stratified during the post-monsoon months and remains so for most part of the year. This behaviour is expected of a lake situated in the tropics with little annual variations in the ambient temperature. Due to this, there is a severe oxygen depletion in the hypolimnion of the lake. The lake often shows phosphorus levels above 25 ppb, the highest level recorded is 40 times over this. As 25 ppb is considered the limit above which phosphorus can cause nuisance algal growth and induce eutrophication (USEPA, 1979), the present status of excessive phosphorus levels in the Kuttiadi lake demands immediate attention. From the-ebservations on phosphorus levels, hypolimnetic oxygen depletion, and presence and abundance of some species of organisms known to abounding over-fertile waters, it may be deduced that the Kuttiadi lake is tending towards eutrophication. lo arrest this trend, it is recommended that the nutrient lodgings from the catchents must be drastically reduced.