SAFER-ET based Assessment of Irrigation Patterns and Impacts on Groundwater Use in the Central Punjab, Pakistan

• Published in: Agricultural water management 2023-11, Vol.289, p.108545, Article 108545
• Main Authors: Nadeem, Adeel Ahmad, Zha, Yuanyuan, Shi, Liangsheng, Zafar, Zeeshan, Ali, Shoaib, Zhang, Yufan, Altaf, Adnan Raza, Afzal, Muhammad, Zubair, Muhammad
• Format: Article
• Language: English
• Subjects: Groundwater; Irrigation Advisory System; Pakistan; Remote Sensing; SAFER algorithm
• ISSN: 0378-3774; 1873-2283
• DOI: 10.1016/j.agwat.2023.108545

The excessive pumping of groundwater during the dry season in Pakistan is identified as a significant concern for groundwater sustainability. Farmers encounter difficulties in efficiently managing irrigation, and adopting the outputs of Irrigation Advisory System (IAS) to improve irrigation practices. Upgrading the existing IAS can help to identify the regions with over-irrigation issues and optimize outreach efforts. To solve these issues, we define the new concept of integrating Gravity Recovery and Climate Experiment (GRACE) total water storage anomalies (TWSA) and Landsat 8 imageries, which can enhance the IAS efficiency by accurately identifying regions facing groundwater depletion by estimating actual crop water consumption through application of the Simple Algorithm For Evapotranspiration Retrieving (SAFER) on Landsat 8 data and Penman-Monteith (PM) method was used to calculate crop water demand using meteorological forcing data from Global Land Data Assimilation System (GLDAS) over the five selected districts of Punjab during the dry seasons of year 2013 to 2020. Comparing actual water consumption (SAFER evapotranspiration (ET)) with in-situ groundwater depth, strong correlations were found between them that are supporting the use of Landsat 8 data for irrigation monitoring. Further, compared SAFER ET was with PM ET to calculate the percentage of over/under irrigated regions, and the results revealed that most of the selected districts were over-irrigated, indicating the potential for excessive irrigation water savings. Our results show that the integration of GRACE TWSA and Landsat 8 data enhance the efficiency of operational IAS and can lead to potential savings of 81% (equivalent to 155 million m3) of groundwater during the dry season in the Central Punjab, Pakistan. Integrating satellite data enhances the global implementation of existing IAS, benefiting regions with unsustainable dry season irrigation practices. This empowers farmers to optimize their agricultural methods through the outputs of precise IAS. •Identification of groundwater depleting regions using Gravity Recovery and Climate Experiment (GRACE) imagery over Punjab province, Pakistan.•Actual crop water consumption estimation through application of the Simple Algorithm For Evapotranspiration Retrieving (SAFER) on Landsat 8 data.•Maximizing the potential water saving by upgrading existing Irrigation Advisory System (IAS) by timely providing information to farmers about crop water ne