Application of Water Quality Index for the spatial evaluation of pond water quality: a study from Vizhinjam Panchayath, Thiruvananthapuram, Kerala, India

Ponds play many vital roles in maintaining the hydro geological equilibrium of an area. Today many ponds are facing permanent deterioration. So it is important to preserve the ponds with respect to the quantity and quality of the water. Ponds play a dual role of storing water on the surface and transmitting water to the subsurface, thus rejuvenating the surface and subsurface water environments in terms of quantity and quality. One of the major advantages of water quality index (WQI) is that, it incorporates data from water quality parameters in to a mathematical equation that rates the health of water quality with number. The present study aimed to determine the water quality of Vizhinjam Panchayath by using water quality index method. The quality of pond water was evaluated by testing various physico-chemical parameters namely pH, TDS, DO, Na, K, Cl, TH, Ca and Mg and their water quality index were calculated. The water quality indexes for all samples were found in the range of 8.4 to 38.11. Most of the pond water samples within study area were found to be excellent to good categories indicating the ponds are suitable for domestic purposes. The study has thus proved that the application of Water Quality Index as a useful technique for the overall assessment of the water quality of a water body. Site specific action plans has also been suggested as part of the study, the strict implementation of which shall ensure the protection and conservation of these small water bodies.