Hussain et al. (2025) Strategic Assessment of Evapotranspiration for Wheat Cultivation in Punjab, Pakistan

Identification

• Journal: Journal of public policy practitioners
• Year: 2025
• Date: 2025-06-30
• Authors: Syed Zaheer Hussain, Maria Zubair, Arsam Ahmad Awan
• DOI: 10.32350/jppp.41.01

Research Groups

• Punjab Information Technology Board, Government of Punjab, Pakistan
• Centre of Excellence in Water Resources Engineering, University of Engineering and Technology, Lahore, Pakistan

Short Summary

This study utilizes Sentinel-2 satellite imagery and Google Earth Engine to map evapotranspiration (ET) across five wheat phenological stages in Punjab, Pakistan, providing a data-driven framework for district-level irrigation zoning and water resource management.

Objective

• To estimate stage-wise and district-level evapotranspiration (ET) for wheat cultivation in Punjab to address the lack of localized data necessary for optimal irrigation planning and water governance.

Study Configuration

• Spatial Scale: Punjab province, Pakistan (approximately 205,000 $\text{km}^2$), analyzed at the district level.
• Temporal Scale: The 2022-2023 wheat growing season (October 2022 to April 2023), divided into five phenological phases: sowing, tillering, flowering, grain filling, and harvesting.

Methodology and Data

• Models used: NDVI-driven ET computational method (utilizing NDVI as a proxy for ET based on calibrated scaling factors) and a vegetation-index-driven crop mask (NDVI > 0.4).
• Data sources: Sentinel-2 satellite imagery (10 m spatial resolution) processed via Google Earth Engine (GEE).

Main Results

• Temporal Trends: ET varied significantly across growth stages, reaching a minimum during the sowing stage ($\approx 1.95\text{ mm/day}$) and peaking during the grain filling stage ($\approx 4.09\text{ mm/day}$).
• Spatial Variations: High water demand (high ET) was consistently observed in the districts of Faisalabad, Multan, and Bahawalpur, whereas the lowest ET levels were recorded in Rawalpindi and Chakwal.
• Policy Insight: The results demonstrate that uniform irrigation programs are inefficient and that water allocation should be prioritized during the flowering and grain filling stages.

Contributions

• Bridges the gap between remote sensing science and public policy by providing a reproducible model for integrating geospatial intelligence into subnational agricultural governance.
• Establishes a scientific foundation for "irrigation zoning," allowing for the transition from reactive to proactive water management and more equitable resource distribution in Pakistan.

Funding

• No funding was received for this research.

Citation

@article{Hussain2025Strategic,
  author = {Hussain, Syed Zaheer and Zubair, Maria and Awan, Arsam Ahmad},
  title = {Strategic Assessment of Evapotranspiration for Wheat Cultivation in Punjab, Pakistan},
  journal = {Journal of public policy practitioners},
  year = {2025},
  doi = {10.32350/jppp.41.01},
  url = {https://doi.org/10.32350/jppp.41.01}
}