Geostatistical investigation of groundwater quality zones for its applications in irrigated agriculture areas of Punjab (Pakistan)

The farmer's income and crop yield are significantly affected in Punjab, Pakistan due to poor-quality groundwater. To observe, monitor and categorized groundwater quality, this research study was carried out in Faisalabad (FSD) and Toba Tek Singh (TTS) districts of Punjab, Pakistan to check its suitability for irrigation with three major parameters (i.e. EC, SAR, and RSC). Geo-statistical water quality analysis was carried out using the GS + and ArcGIS includes three following basic components: normalized histograms, semivariograph, and Kriging. The cross-validation techniques were used to determine the accuracy. A hydro-economic model was applied to observe the impact of groundwater quality on crop yield and farmers’ income. It was found that the percent area under a good groundwater quality zone in FSD was about 25% fewer than TTS. In FSD, the majority area of the aquifer was under marginal (50–55%) to poor (39–44%) quality groundwater zones and salinity and sodicity are major threats depicted by EC and RSC, respectively. In TTS district, salinity was the only major risk to groundwater quality as about 45% area was under poor quality zone. The overall aquifer’s area under about good (~ 33%), marginal (~ 29%) and poor (~ 38%) quality groundwater zone. It was found that the impact of the monsoon season was found not considerable on the groundwater quality of both districts. Comparing the economic models in two districts using the different quality water it was found that the BCR (Benefit Cost Ratio) was recorded 2.31, 2.13 and 1.73 in FSD district while in TTS district the BCR was 2.35, 2.09 and 1.58 for good, marginal and poor-quality zone, respectively. The results of the research recommend that monitoring and mapping of groundwater are necessary for proper management of groundwater resources, leading to reduced economic losses and increased crop yield.