International Journal of Emerging Technology and Advanced Engineering Website: www.ijetae.com (E-ISSN 2250-2459, UGC Approved List of Recommended Journal) Volume 7, Special Issue 1, September 2017 Water Quality Assessmentof Ashtamudi Lake Using Nsfwqi Surya Lekshmiprasad 1 , K Mophin Kani 2 UKF College of Engineering & Technology, Kollam-691302, Kerala, INDIA. Abstract: A water quality index provides a single number that gives overall water quality at a definite location and time grounded on some water quality parameters. It turns complex water quality data into data that is understandable by the common people.National Sanitation Foundation Water Quality Index (NSFWQI) is a common method adopted to calculate WQI. The present investigation was planned to assess the quality ofAshtamudi Lake (Latitude 8º59’N, Longitude76 º 36’E), Kollam district, Kerala, India. It supports around 43 mangrove species, 57 birdspecies, 97 species of fishes. Coconut husk retting, fishing, inland navigation and a fishing harbour at Neendakara are other economic benefits provided by this lake. It is getting polluted day by day due to offshore activities like wastes from hotels,agricultural activities,farms, and wastes from municipal waste disposal site. The case study describesextend of water pollutionAshtamudi lake and also suggest the measures to mitigate pollution. The detailed physicochemical examinations are assessed forfour months (December 2016 to March2017) and NSFWQI value of Ashtamudi Lake is finally calculated as 27.5 describes as bad qualityof water. Keywords:Ashtamudi Lake, NSFWQI, pH, DO, BOD, TS, Nitrates, Phosphorous, Turbidity, Temperature I. INTRODUCTION Tremendous increase in population caused significant increase for the need of natural resources. The direct consequences are for quantity and quality of the available freshwater for direct human consumption. Water quality indices is a serious component of global integrated water resources handling[65]. When water quality indices are not met, water users must either fee an extra cost for water treatment or earn at least increased risks of damage or loss. Gradually, the major efforts and costs involved in water management are dedicated to water quality protection and management. Struggles among various users of water are over issues involving water quality as well as water quantity[54]. Natural water bodies are able to serve many uses, including the transport and assimilation of wastes. But as water bodies integrate these wastes, their quality changes. If the quality drops to the extent that other useful uses are adversely affected, the assimilative abilities of those water bodies have been increased with respect to those affected uses[5]. The most fundamental human needs for water are for drinking, cooking and personal sanitation. To meet these needs, the quality of the water used must pose no risk to human health. The quality of the water in nature also affects the condition of ecosystems that all living organisms depend on. At the same time, humans use water bodies as convenient basins for the disposal of domestic, industrial and agricultural wastewaters. This of course degrades the quality of those water bodies. Water resources management involves in the monitoring and management of water quality[9]. Various models have been developed to assist in predicting the water quality impacts of alternative land and water management strategies and practices[16]. All living organisms require water of sufficient quantity and quality to survive, although different aquatic species can tolerate different levels of water quality[54]. Unfortunately, in developed world it is no longer safe to drink water from natural surface waters or ground waters; they usually need to be treated before they become suitable for human consumption. Treatment is not a practical option for recreational, bathing, or for maintaining the healthiness of fish, shellfish and other organisms found in natural aquatic ecosystems[64]. Thus, standards stating minimum acceptable levels of quality are fixed for most ambient waters. Numerous other uses have their own standards as well. Irrigation water must not be too saline or contain toxic substances that can be absorbed by the plants. Water qualitystandards for industry can be very difficult, depending of course on the particular industrial processes. Due to difficulties related to water resources it is important to develop monitoring, research and management movements in order to ensure their effective management. The water spread area for Ashtamudi Lake in these couple of years are found to be shrinking(1999 – 6424 ha, 2003 – 6140 ha, 2006 – 5734 ha)[39].The bank areas become a waste dumping site for the town because most of the houses and industrial establishments, lake receives effluents directly from nearby food processing industries, paper mills and tourist activities. Apart from that, oil spillage from motor boats is affecting fish population. Another source of pollution is the runoff from agricultural fields in adjoining areas. Chemical fertilisers and pesticides are causing eutrophication of the lake. Small-scale industries like coconut husk retting also contribute heavily to its organic pollution[54].For examining impacts of these activities water quality assessment is needed. This study reveals surface water International Conference on Innovative Developments in Engineering & Applied Sciences (IDEAS)-2017 Organized by UKF College of Engineering & Technology, Parippally, Kerala, India| 130