Fish Farming Effects on Infiltration Dynamics in Runoff Water Harvesting Ponds: An Experimental Study in Semi-Arid Burkina Faso

In semi-arid regions, such as the Sahel, infiltration losses in earthen runoff water harvesting ponds (RWHPs) reduce the efficiency of supplemental irrigation and aquaculture. Engineered sealing methods, such as synthetic liners, are effective but often unaffordable in rural areas. This study evaluates whether fish farming can promote natural sealing of RWHPs through biological accumulation of sediments and organic matter.

A 100-day field experiment was conducted in Kamboinsin, central Burkina Faso, using twelve fish-stocked RWHPs and one unstocked control pond. All ponds were managed uniformly, and daily monitoring of water levels, rainfall, and evaporation was performed. Infiltration rates were calculated from the water balance. Statistical analysis included Mann-Kendall trend tests and paired t-tests to assess temporal and treatment effects.

No significant temporal trends in infiltration were observed, but fish-stocked ponds showed a 95% reduction in mean infiltration compared to the control (4.7 mm/day vs. 159.3 mm/day, p< 0.0001).

The results indicated that fish farming enhances the development of a biological sealing layer, reducing seepage losses. This finding supports integrating aquaculture into water harvesting systems as a sustainable practice to improve water retention, increase resource efficiency, and align with climate adaptation strategies in semi-arid regions.

Fish farming is not a substitute for engineered liners but represents a promising, nature-based complement in RWHPs under resource-limited conditions. Limitations include the short monitoring period (100 days) and reliance on a single control pond, which may constrain generalizability. Further studies are required to test long-term performance and broader applicability.