Sand dam contributions to year-round water security monitored through telemetered handpump data

Area of Science:

• Environmental science
• Water resource management
• Hydrology

Background:

• Sand dams are a key rainwater harvesting technique in arid and semi-arid regions.
• Handpumps are the primary improved method for water abstraction from sand dams, vital for drinking water security.

Purpose of the Study:

• To analyze handpump abstraction data from sand dams to assess their contribution to year-round water security.
• To investigate the factors influencing water abstraction rates and the reliability of sand dams during dry seasons.

Main Methods:

• Fitted 30 handpumps with accelerometers and cellular transmitters to record hourly water volume abstracted.
• Analyzed data from 26 sites (April 2019 - October 2021) alongside qualitative data.
• Focused analysis on the long dry season to evaluate year-round water supply reliability.

Main Results:

• Water abstraction via handpumps was over 20 times higher in the long dry season compared to other seasons.
• Higher abstraction rates were observed at sites with increased salinity, livestock use, and larger dam wall areas.
• 21 out of 26 wells showed continued abstraction at the end of at least one long dry season, but spatial and temporal variations exist.

Conclusions:

• Sand dams, through handpump abstraction, significantly contribute to year-round water security, especially during dry periods.
• Understanding abstraction heterogeneity is crucial for climate change adaptation and optimizing sand dam design.
• Quantifying sand dam contributions aids in selecting appropriate water management techniques for resilience.