Talpur et al. (2026) Estimating Seasonal Water Losses from Supply-Demand Analysis Using Satellite-Derived Cropping Patterns: A Case Study

Identification

• Journal: Social Science Academic
• Year: 2026
• Date: 2026-01-04
• Authors: Mir Moazzam Ali Talpur, Hamza Khalid, Tingting Chang, Mir Ghazzanfar Ali Talpur, Ghulam Hussain Khoso
• DOI: 10.37680/ssa.v3i2.8700

Research Groups

• Hohai University, China
• Sindh Agriculture University, TandoJam, Pakistan

Short Summary

This study developed a cost-effective and transferable method using satellite imagery and a crop water need model to quantify seasonal water losses in a canal-command area, revealing that approximately 33.5% of the supplied water was lost, with application losses slightly exceeding conveyance losses.

Objective

• To demonstrate a feasible, cost-effective, and transferable method for quantifying seasonal water losses in canal-command irrigation systems by integrating satellite imagery, a crop water need model, and straightforward discharge measurements.

Study Configuration

• Spatial Scale: A 143.26-hectare (354-acre) command area of watercourse number 5AR in Union Council (UC) Chukhi, Hyderabad district, Pakistan.
• Temporal Scale: The Rabi season (September to February). Meteorological data covered 5 years, and Landsat 8 imagery was acquired in December 2017.

Methodology and Data

• Models used:
  • CROPWAT model (for reference and crop evapotranspiration, ET0 and ETc).
  • ArcGIS 10.1 (for image processing, classification, and area estimation).
  • Maximum Likelihood Classifier (for supervised image classification).
  • Rhoades equation (for leaching requirement, LR).
• Data sources:
  • Landsat 8 Operational Land Imager (OLI) satellite imagery (from USGS GloVis portal).
  • Meteorological data (minimum and maximum air temperature, relative humidity, wind speed, sunshine/radiation) for the study area.
  • Crop calendars and stage-specific crop coefficients (Kc values).
  • Field discharge measurements for surface water (at Mogha outlet) and groundwater (from tube wells).
  • Local information on cropping patterns and spatial distribution of orchards and field crops for visual verification.

Main Results

• Cropping Pattern: Out of the 143.26 hectares (354 acres) command area, 29.6% was uncultivated. Major cultivated crops included wheat (24.5% of cultivated area), mango (17.5%), banana (14.0%), and sugarcane (7.1%).
• Climatic Conditions: Average reference evapotranspiration (ET0) during the Rabi season was 5.12 mm/day. Monthly ET0 ranged from 3.58 mm/day (December) to 8.06 mm/day (September). Wind speeds ranged from 1.81 m/s to 5.41 m/s (156-467 km/day), and solar radiation from 166.67 W/m² to 237.27 W/m² (14.4-20.5 MJ/m²/day).
• Crop Water Demand (Volumetric): Total seasonal volumetric demands were highest for banana (208947.2 m³), followed by wheat (145180.2 m³), mango (100590.8 m³), and sugarcane (95469.7 m³). Perennial orchard crops (banana, mango) and sugarcane dominated the seasonal water demand per unit area.
• Water Supply: The total seasonal water supply was 1027980.7 m³ (833.45 acre-ft), consisting of 530777.7 m³ (430.3 acre-ft) surface water and 497203.0 m³ (403.04 acre-ft) groundwater, indicating nearly equal reliance on both sources. Average tube well discharge was 0.018 m³/s (18.0 L/s), and Mogha outlet discharge was 0.0855 m³/s (3.02 cusecs).
• Seasonal Water Losses: Total seasonal water losses were estimated at 344883.9 m³ (279.6 acre-ft), representing 33.5% of the total water supplied.
  • Conveyance losses accounted for 15.0% of the total supply (154160.5 m³ or 125 acre-ft).
  • Application losses accounted for 18.5% of the total supply (189960.9 m³ or 154 acre-ft), exceeding conveyance losses by approximately 3.5 percentage points.

Contributions

• Provides a feasible, cost-effective, and transferable methodology for diagnosing seasonal irrigation performance and quantifying water losses at the watercourse level, particularly valuable for data-limited canal-command systems.
• Offers a hybrid approach combining free satellite imagery, basic climatic data, standard software (ArcGIS, CROPWAT), and simple field discharge measurements, making it widely applicable.
• Enables spatially explicit crop-specific water demand estimates and a clear accounting of water supply and losses at a seasonal scale.
• Identifies specific intervention areas (e.g., improving on-farm water management, selective lining of watercourses) for enhancing water-use efficiency and promoting sustainable irrigation.

Funding

Not explicitly mentioned in the provided text.

Citation

@article{Talpur2026Estimating,
  author = {Talpur, Mir Moazzam Ali and Khalid, Hamza and Chang, Tingting and Talpur, Mir Ghazzanfar Ali and Khoso, Ghulam Hussain},
  title = {Estimating Seasonal Water Losses from Supply-Demand Analysis Using Satellite-Derived Cropping Patterns: A Case Study},
  journal = {Social Science Academic},
  year = {2026},
  doi = {10.37680/ssa.v3i2.8700},
  url = {https://doi.org/10.37680/ssa.v3i2.8700}
}