Ashraf et al. (2025) Geospatial Investigation of Cryosphere-Fed Irrigation System in High-Altitude Hunza Basin, Pakistan

Identification

• Journal: Water Conservation Science and Engineering
• Year: 2025
• Date: 2025-11-18
• Authors: Arshad Ashraf, Imran Ahmad
• DOI: 10.1007/s41101-025-00458-w

Research Groups

Climate, Energy and Water Research Institute, National Agricultural Research Centre (NARC), Islamabad, Pakistan.

Short Summary

This study evaluates the existing status and characteristics of cryosphere-fed kuhl irrigation systems in the high-altitude Hunza Basin, Pakistan, using geospatial techniques and ground information, revealing their diverse lengths, primary water sources, and multi-purpose applications.

Objective

• Develop an inventory of the kuhl irrigation system.
• Characterize the kuhl system and its associated biophysical and environmental factors.
• Identify the major application fields of the kuhl system in the Hunza Basin.

Study Configuration

• Spatial Scale: Hunza River Basin, Pakistan (approximately 15,678 km²), located between 74.04°E to 75.77°E longitude and 36.05°N to 37.08°N latitude, with elevations ranging from 1380 m to 7788 m above mean sea level. Specific analyses were conducted within a 100 m buffer zone around the kuhl network (approximately 88.7 km²).
• Temporal Scale: Google Earth imagery (2020), ESRI Global Land Cover Dataset (2020), and monthly rainfall data from 1990 to 2019 for the R-factor calculation.

Methodology and Data

• Models used: Revised Universal Soil Loss Equation (RUSLE) for soil erosion risk assessment.
• Data sources:
  • Remote Sensing: Google Earth imagery (2020), Sentinel-2 data (for ESRI Global Land Cover Dataset 2020), Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) C-band radar data.
  • Observation/Ground Data: Global Positioning System (GPS) surveys, field observations, literature review, soil samples for K-factor calculation, monthly rainfall data (1990-2019), and resource data (physiography, geology, landforms/soils, hydrology) from Survey of Pakistan, Geological Survey of Pakistan, Soil Survey Department, and Water and Power Development Authority (WAPDA).

Main Results

• A total of 225 kuhls were identified with a cumulative length of approximately 468.4 km.
• Kuhl length distribution: 23.1% were small (< 1 km), 70.7% medium (1–5 km), and 6.2% large (> 5 km).
• Major water intake sources: 92.4% from meltwater streams, 5.4% from valley glaciers, and 2.2% directly from the Hunza River.
• Kuhl network starting elevations ranged from 1482 m to 3447 m (mean 2594 m), and ending elevations from 1469 m to 3366 m (mean 2472 m).
• Within the 100 m kuhl buffer zone (88.7 km²):
  • Approximately 20% of the kuhl length was within 1000–2000 m elevation, and 58.3% within 2000–3000 m.
  • 48.8% of the buffer comprised moderately steep slopes (15°–30°), and 13.4% very steep slopes (> 30°).
  • Dominant geology included metamorphic rocks (45.3%), sedimentary rocks (17%), and glacial deposits (16.4%).
  • Major land use types were rangeland (59.2%) and bare ground (30.4%).
  • The mean soil erosion rate was approximately 20.2 tons per hectare per year. 8.8% of the buffer area exhibited high to severe erosion risk (> 50 tons per hectare per year), and 9.3% showed moderate risk (25–50 tons per hectare per year).
• Major kuhl applications included agriculture + orchards + domestic use (58.2% of kuhls) and agriculture + orchards (19.1% of kuhls). Approximately 26.8 km of kuhls are piped or concrete-structured, often linked to hydropower generation.

Contributions

• Provided the first comprehensive inventory and characterization of the kuhl irrigation system in the high-altitude Hunza Basin.
• Revealed the multifunctional aspects, altitudinal characteristics, influential biophysical factors, and diverse application fields of the kuhl system.
• Strengthens the knowledge base for sustainable agricultural water management, food, and water security in the remote mountainous region.
• Offers findings that can inform the development of strategies for integrated irrigation, environmental risk management, land use planning, and water accounting.

Funding

No funds, grants, or other support were received during the preparation of this manuscript.

Citation

@article{Ashraf2025Geospatial,
  author = {Ashraf, Arshad and Ahmad, Imran},
  title = {Geospatial Investigation of Cryosphere-Fed Irrigation System in High-Altitude Hunza Basin, Pakistan},
  journal = {Water Conservation Science and Engineering},
  year = {2025},
  doi = {10.1007/s41101-025-00458-w},
  url = {https://doi.org/10.1007/s41101-025-00458-w}
}