SIMULATING THE EFFECT OF INCREASED AREA UNDER DIRECT SEEDED RICE AND CANAL WATER SUPPLY ON GROUND WATER TABLE UNDER CLIMATE CHANGE IN FIVE SELECTED CENTRAL PUNJAB DISTRICTS, INDIA

Abstract

The groundwater table has been critically declined in the Central Punjab districts of Moga, Barnala, Patiala, Sangrur, and Ludhiana, India in past years due to its major rice-wheat cropping system and excessive extraction of groundwater for irrigation purposes. Devising appropriate management strategies for improving groundwater table in those districts are of paramount importance. In the present study, the groundwater table variation was estimated for the RCP4.5 scenario using bias-corrected climatic data derived from IITM-RegCM4 based six climate model ensembles and validated SWAT-GMS model under six definitive management strategies involving more area under DSR and enhancement of canal water supply were formulated for the study districts. A significant rise by 4 - 6.8 cm year-1 in the groundwater table was simulated at p<0.05 under strategy-IV to strategy-VI for Moga district, 3.1-8.4 cm year-1 for Barnala district under strategy-I to Strategy-VI, 2.9 - 4.8 cm year-1 for Sangrur district under strategy-V to strategy-VI, 4.9 – 7.1 cm year-1 for Patiala district under strategy-III to strategy-VI and 7.6 – 10.8 cm year-1 under strategy-IV to strategy-VI for Ludhiana district was simulated during 2022-2030. It was observed that increasing the area under the DSR planting method of rice by 25 to 50 % besides augmentation of canal water supply by 20 to 30 % would result in arresting the decline in the water table by a minimum of 2.9 cm to a maximum of 10.8 cm per year in central Punjab, India. Thus, the adoption of the DSR cultivation method along with the augmentation of canal irrigation would be the most effective approach for arresting the declining water table and leading to the attainment of sustainability in groundwater usage in the region.