Spatio-Temporal Variations of Hydrogeochemical Parameters and Qualitative Assessment of Groundwater in the Chellur Watershed, Malappuram District, Kerala, India

The primary objective of this work is to examine the spatio-temporal variations of groundwater quality parameters of Chellur watershed in Kerala and to assess the suitability of groundwater for irrigation purposes. Groundwater samples were collected from 10 open wells and 2 bore wells during pre-monsoon and post-monsoon seasons. The samples were analyzed for Electrical Conductivity (EC), pH, Total Dissolved Solids (TDS), Total Hardness (TH), major ions such as calcium, magnesium, sodium, potassium, chloride, etc. The spatial variation diagrams of various physico-chemical parameters were drawn using ArcGIS. The suitability of groundwater for irrigation purposes was assessed using the parameters such as EC, SAR (Sodium Adsorption Ratio) and Sodium percentage (Na%). From Wilcox plot, it was observed that all the samples of both pre-monsoon and post-monsoon seasons fall in the excellent to good category. The plot of USSL diagram showed that the groundwater samples from Chellur watershed belongs to C1- S1 (low salinity-low SAR) and C2-S1 (medium salinity-low SAR) categories in both seasons. It could be inferred that majority of groundwater samples in the study area fall within the permissible limits prescribed for irrigation.