Impact of paddy on groundwater declination in Central Punjab

Abstract

Central Punjab includes over 40% of the state of Punjab. In Central Punjab, groundwater levels are dropping by more than 1 m every year. The primary cause of groundwater depletion in Central Punjab between 1998 and 2019 is presented in this paper. In order to detect any sudden changes in the area under paddy and the depth of groundwater, Pettitt's test was used. Based on change points and trends, the entire duration was split into two time periods: 1998–2008 (T1) and 2009–2019 (T2); rainfall, potential evapotranspiration, and paddy area were assessed in both periods with 1998–2019 (T3). The slope methodology developed by Mann–Kendall and Sen demonstrated the trend analysis. The findings showed that changes in climate were caused by humans during the 1998–2008 era, changes in meteorological variables were caused by humans during the 2008–2019 period, and changes in climate were caused by humans during the T3 period. The major growing trend of groundwater depth loss is thought to be caused by the combined effects of rainfall variations, an increase in the maximum temperature, cropping intensity, and the number of pumping units. HIGHLIGHTS Paddy area has been increasing in Punjab for the last 20 years, and this increase is causing a huge decrease in groundwater levels.; Pettitt's test was applied to see in which year an abrupt change happened.; Mann–Kendall and Sen's slope were applied to analyze the trend.; Rainfall was not enough for groundwater recharge as compared to declination due to the paddy area.; Central Punjab must evolve decision-making tools for arresting groundwater (GW) decline.;

Keywords

• retain groundwater
• mann–kendall
• pettitt's test
• rainfall
• sen's slope
• temperature