7 N Save Nature to Survive 10(1&2): 07-12, 2016 QUARTERLY A COMPARATIVE ASSESSMENT OF WATER QUALITY INDEX OF SURFACE (RIVER) WATER AND GROUND WATER ALONG THE BUDHI GANDAK BELT USING CORRELATION ANALYSIS AT KHAGARIA (BIHAR) DIKSHA SHARMA* AND SUNIL KUMAR CHOUDHARY Department of Botany, Environmental Biology Research Laboratory, Tilka Manjhi Bhagalpur University, Bhagalpur - 812 007, Bihar, INDIA e-mail: diks1336@yahoo.com INTRODUCTION Water is vital to the existence of all living organisms, but this valued resource is increasingly being threatened as human populations grow and demand more water of high quality for domestic purposes and economic activities. The quality of any body of surface or ground water is a function of either or both natural influences and human activities. Rivers and ground water are the important sources of fresh water. These fresh water resources are essential for sustainable development. Rivers play critical role in the quality and supply of drinking water by ensuring a continuous flow of surface water and helping recharge underground aquifers. The changes in the natural interaction of ground water and surface water caused by human activities and that can potentially have a significant effect on aquatic environments (Winter et al., 1998). Disposal of industrial effluent and sewage into surface water cause ground water pollution. Ground water contamination is generally irreversible i.e. once it is contaminated; it is difficult to restore the original water quality of the aquifer by stopping the pollutants. It therefore becomes imperative to regulate and monitor the quality of ground water and river water to devise ways and means to protect. Water Quality Index (WQI) may be an important tool for understanding of the interaction of ground water and surface water, in terms of their quality for human consumption for drinking purposes. Many workers have studied on comparative WQI of surface water and ground water on the basis of physico-chemical results (Mahananda et al., 2010, Maheshwari et al., 2011, Meitei et al., 2013, Solanki et al., 2014). Some works are also reported on physico- chemical analysis of ground water in river floodplains (Abbas et al., 2012, Mumtazuddin et al., 2012). Budhi Gandak is one of the important tributaries of the Ganga in north Bihar. The origin of Budhi Gandak is at the West Champaran near Ramnagar and Bagaha. It is a rain fed river and flows through West Champaran, East Champaran, Muzaffarpur, Samastipur, Begusarai and flows into the Ganges near Khagaria. The Budhi Gandak river water and ground water in the river floodplains and in urban areas near Khagaria have multiple uses. The major sources of pollution of the river include agricultural runoff containing fertilizers, pesticides and insecticides from the floodplain containing toxic chemicals, abstraction of river water for irrigation, navigation by motorized country boats, burning of dead bodies at cremation ghats on the river bank and other anthropogenic activities which may deteriorate natural interaction of river water and ground water. Thus the objective of present study is to assess comparative status of the water quality of Budhi Gandak River and ground water (mainly hand pumps) in river floodplain and Khagaria town using Water Quality Index as an indicator of water quality. ABSTRACT The present work deals with the assessment of the Water Quality Index (WQI) of the ground water (hand pumps) as well as surface water (Budhi Gandak River) in Khagaria town, Bihar in order to ascertain the quality of water for public consumption, recreation and other purposes. In this study, WQI was determined on the basis of seasonal variations in important water quality parameters such as pH, temperature, total dissolved solids (TDS), electrical conductivity (EC), total hardness (TH), bicarbonate (HCO 3 - ), phosphate (PO 4 -P), nitrate (NO 3 -N ), chloride (Cl - ) and turbidity. The results in the present study indicated that most of the water quality parameters analyzed were within the WHO and BIS limits for drinking water except turbidity values that exceeded permissible limit in surface water and some samples of ground water. WQI values of surface water at all the three sites in all the three seasons were categorized in Excellent (40.09-42.35), Good (52.09-99.13) and Poor (103.67-126.76) categories whereas ground water samples in Excellent (42.92- 49.85) and Good (51.23-73.79) categories. WQI was in good correlation with phosphate and turbidity in all the three seasons at all the three sites. The study suggests that river water is not suitable for human consumption during monsoon months. Ground water is suitable for drinking in all the three seasons at all the three sites. Received : 20.09.2015 Revised : 13.11.2015 Accepted : 24.01.2016 *Corresponding author KEY WORDS River Budhi Gandak & floodplain Surface Water, Ground Water, WQI