Sayl et al. (2026) Sustainable Water Management for Agriculture to Mitigate Climate Change Effects

Identification

• Journal: Water Resources Management
• Year: 2026
• Date: 2026-02-01
• Authors: Khamis N. Sayl, Nese Yaman, Isam M. Abdulhameed, Hana Khalaf
• DOI: 10.1007/s11269-026-04504-7

Research Groups

• Department of Dams and Water Resources, College of Engineering, University of Anbar- Iraq
• Department of Farm Structures and Irrigation, Faculty of Agriculture, Dicle University, Diyarbakır, Turkey
• Upper Euphrates Center for Sustainable Development Research, University of Anbar- Iraq
• Directorate of Materials Research, Ministry of Science & Technology, Baghdad, Iraq

Short Summary

This study developed an integrated methodology using the WATSUIT model and Geographic Information System (GIS) to mitigate drought impacts in Iraq by assessing the suitability of saline water from the Main Outfall Drain (MOD) for irrigating salt-tolerant crops, complemented by rainwater harvesting for soil washing. The findings indicate that while Basra's MOD water is too saline, other regions along the MOD can utilize this water with appropriate leaching fractions and rainwater harvesting to support sustainable agriculture.

Objective

• To assess how water quality varies spatially along the Main Outfall Drain (MOD) system.
• To forecast the expected evolution of soil salinity under different leaching fractions when using MOD water for irrigation.
• To determine if rainwater harvesting can effectively support soil leaching when saline water is used for irrigation.

Study Configuration

• Spatial Scale: The Main Outfall Drain (MOD) system in central and southern Iraq, covering a 565 km path and an area of 12,018 km² (extending 10 km to the left and right of the drain). Five monitoring stations were selected: Baghdad, Hilla, Diwaniyah, Nasiriyah, and Basra. The study area is situated within longitudes 42° 00’ 00″ to 48⁰00’ 00″ East and latitudes 30⁰00’ 00″ to 32°00’ 00″ North.
• Temporal Scale: Water and soil characteristics data were collected for wet and dry seasons from 1995 to 2024. Satellite images (Landsat 8) were acquired in August 2023. Rainfall data spanned from 1991 to 2022. The WATSUIT model was used to forecast steady-state soil salinity conditions over periods of approximately 5–7 years.

Methodology and Data

• Models used:
  • WATSUIT model: Used to forecast steady-state soil salinity conditions resulting from saline water irrigation.
  • Geographic Information System (GIS) (ArcGIS 10.8): Utilized for spatial analysis, mapping land use/cover, distributing water and soil characteristics, and identifying potential rainwater harvesting sites.
  • Supervised Classification (Maximum Likelihood Classification): Applied to Landsat 8 satellite images for land use/cover determination.
  • Boolean overlay (AND operation): Used to determine sustainable development areas.
• Data sources:
  • Satellite images: Landsat 8 OLI (2023) from the United States Geological Survey (USGS) Earth Explorer platform.
  • Digital Elevation Model (DEM): 30 m spatial resolution from USGS, used to derive slope and stream order maps.
  • Rainfall data: M.S. Rainfall date (xlsx, xlsm format).
  • Soil data: FAO Soil type.
  • Water quality parameters (pH, Total Dissolved Solids (TDS), Electrical Conductivity (EC), Sodium (Na), Magnesium (Mg), Calcium (Ca), Sodium Adsorption Ratio (SAR)) and soil characteristics (pH, EC, TDS): Collected from relevant peer-reviewed scientific journals for wet and dry seasons (1995–2024).
  • Validation data: 180 ground truth locations for land use/cover accuracy assessment.

Main Results

• Water Quality Spatial Distribution: Electrical conductivity (EC) values in the MOD water ranged from 4.02 dS/m in Baghdad to 40.4 dS/m in Basra during the wet season, with concentrations increasing towards the south, particularly in summer. Total Dissolved Solids (TDS) ranged from 1500 ppm in northern sections to 35000 ppm in Basra. Overall, the water quality was deemed unsuitable for drinking but adequate for irrigating salt-tolerant crops.
• Soil Salinity Forecasting (WATSUIT Model): The WATSUIT model indicated that water from Basra was unusable for irrigation, even with high washing requirements (leaching fraction, LF = 0.4). However, other sites were acceptable with an LF of 0.1. Al-Diwaniyah showed significant improvement in salinity rates at an LF of 0.2, while Al-Nasiriyah's salinity remained high even at LFs between 0.2 and 0.4.
• Rainwater Harvesting Potential: The study identified significant runoff capacity in the area. Suitable areas for rainwater harvesting were mapped: 1694 km² as "little suitable," 8053 km² as "medium suitable," and 2271 km² as "highly suitable."
• Sustainable Development Areas: Analysis of EC, LULC, and soil data identified areas suitable for agricultural use. Large parts of Baghdad, Hilla, and Diwaniyah (1543 km²) were suitable for fruit trees (palm, figs, olives, pomegranates), grains (barley, wheat, corn), and fodder crops. Areas in Basra and Nasiriyah (2338 km²) with EC values > 12 dS/m require dilution with fresh water or soil washing. Total dissolved salts generally exceeded 2000 ppm, confirming suitability for salt-tolerant plants like barley, cotton, and beets.
• Mitigation Strategy: The integrated approach of using rainwater harvesting for soil washing in conjunction with saline MOD water can effectively mitigate climate change impacts, remove soil salts, and support the irrigation of salt-tolerant crops, thereby reducing the water gap.

Contributions

• Proposed an integrated framework combining WATSUIT modeling, GIS-based spatial analyses, and rainwater harvesting assessment along the entire 565 km Main Outfall Drain (MOD) system in Iraq.
• Provided a novel approach to simultaneously evaluate the spatial variability of saline water quality, forecast long-term soil salinity under different leaching conditions, and identify the role of rainwater harvesting in mitigating salinization.
• Offered both methodological innovation and practical value for climate change adaptation and sustainable irrigation management in arid and semi-arid regions.
• Aligned with Sustainable Development Goal 6 (Clean Water and Sanitation) by promoting the safe reuse of saline water, reducing pressure on freshwater resources, and encouraging integrated water resource management under climate change conditions.

Funding

• Open access funding provided by the Scientific and Technological Research Council of Türkiye (TÜBİTAK).
• The authors declared that no funds, grants, or other support were received during the preparation of this manuscript.

Citation

@article{Sayl2026Sustainable,
  author = {Sayl, Khamis N. and Yaman, Nese and Abdulhameed, Isam M. and Khalaf, Hana},
  title = {Sustainable Water Management for Agriculture to Mitigate Climate Change Effects},
  journal = {Water Resources Management},
  year = {2026},
  doi = {10.1007/s11269-026-04504-7},
  url = {https://doi.org/10.1007/s11269-026-04504-7}
}