Evaluating evaporation losses from agricultural ponds with shelter net covers by integrated Dalton model

Water harvesting infrastructures represent one of effective solution for sustainable water management for agriculture and climate change adaptation strategies. However, evaporation from such structures is a critical challenge for stakeholders as it reduces the effective availability of stored water. Partial surface covering has emerged as a practical solution to suppress evaporation and improve water storage efficiency. In this case, quantifying the effectiveness of cover treatments is essential for water authorities and farmers to assess water loss and make informed decisions before implementation. This study aims to develop a practical method for quantifying the performance of cover treatments in reducing evaporation. An integrated model based on the Dalton equation, was applied to estimate evaporation losses from open ponds and to derive a cover factor for partially covered systems. The model calibrated with field data collected in 2024 and validated with 2025 measurements, achieved strong predictive accuracy (R² = 0.894). Experimental results further demonstrated that a 50 % shade net significantly lowered water surface temperature relative to uncovered ponds, achieving an average evaporation suppression rate of 20 %. Over the four-month monitoring period, the treatment reduced daily water loss by approximately 2.5 m³ , corresponding to a cumulative saving of about 110 m³ compared to uncovered reservoirs. These findings provide a reliable and transferable framework for stakeholders such as water authorities and farmers to estimate evaporation losses under partial cover treatments. Overall, this approach enhances water management efficiency and reduces the risk of inaccurate or costly investments in agricultural water harvesting systems.