MODELLING OF NITRATE TRANSPORT IN GROUNDWATER USING MODFLOW IN MUKTSAR DISTRICT, PUNJAB, INDIA

Abstract

Groundwater is vital to the Indian economy. According to a World Bank research, groundwater contributes 9% of India's GDP. Groundwater has become increasingly important as a source of drinking water and crop irrigation due to its abundance and lower risk of pollution compared to surface water. As a result, the world’s dependency on this resource has grown over time. The source of the NO3 in groundwater includes industrial effluents and extensive use of fertilizers, and seepage from excreta waste from humans and animals. It can seep into the soil and contaminate groundwater. In India, more than 50% of districts have nitrate levels that exceed permissible limits. This means that the water in these districts is not safe for drinking. Nitrate contamination is a widespread problem in many parts of India. Punjab is one of the states in India that uses an excessive amount of chemical fertilisers, with a per hectare usage of 243 kg/year, the highest of any state in the country. This study has used groundwater level and nitrate data to simulate the contaminant transport model and groundwater flow model which is applied to unconfined aquifer at a depth of 30 meter below ground level. The data collected from the CGWB and INDIA-WRIS revealed the concentration of nitrate in range of 24mg/l to 480mg/l. This study was conducted at 6 different locations of Muktsar district i.e. Bhaliana, Balocha Khera, Doda, Kuttianwali, Lambi , Muktsar. MODFLOW and MT3DMS is the model used to assess the groundwater flow movement and the contaminant transportation process of nitrate. The results showed an increase in nitrate concentration for Kuttianwali and Bhalaina area at 300 meter away from point source as 66mg/l and 48mg/l respectively after a period of 1100 days. ArcGIS software is used for generation of spatial distribution of nitrate over years and generation of elevation contour maps.