C. GAJENDRAN, P. THAMARAI AND R.BASKER
Abstract
Water quality degradation in river systems has emerged as a key problem in Asia during the last decades. Water quality index is a means to summarize large amount of water quality data into simple terms (e.g., Good or Bad, Clean or Contaminated) for reporting to authorities, management and the public in a consistent manner. Current water quality indices provides indications of the quality of water influenced by domestic (point source), some general industrial (point source) and agricultural runoff (Non-Point source). The purpose of the investigation were (1) to provide an overview of the quality of surface water, (2) to determine the spatial distribution of Surface water quality during the period 2002 to 2006, so that the trend of the water quality can be assessed for future development plans, and (3) to map surface water quality in the study area by using GIS and Geo-statistical techniques. The present study focuses on the surface water quality in Nambiyar Basin, Tamil Nadu, India. The Physico-chemical parameters such as pH, DO, TDS, NO3, BOD, COD, Total Alkalinity, Total Hardness, Ca, Mg, Cl, SO4, F of the basin were taken in to account to decide the quality characteristics of the basin. The samples were collected from six sampling points in the basin during the years 2002, 2003, 2004, 2005 and 2006. Arc GIS and Arc GIS Geo-statistical Analyst were used for the generation of various thematic maps and Arc GIS Geo-statistical Analyst to produce the final weighted overlay analysis. An interpolation technique, ordinary kriging, was used to obtain the spatial distribution of surface water quality parameters. The results show that most of the basin has moderate to poor water quality for drinking purpose and, in general, the surface water quality of the basin decreases northwest to southeast.