دانشگاه محقق اردبیلی مدل سازی و مدیریت آب و خاک 2783-2546 5 4 2025 10 23 Application of light concrete balls as floatation balls to reduce evaporation from free water surfaces Application of light concrete balls as floatation balls to reduce evaporation from free water surfaces 211 222 4110 10.22098/mmws.2025.18231.1672 FA Jahangir Abedi Koupai Professor, Department of Water Sciences and Engineering, College of Agriculture, Isfahan University of Technology, Isfahan, Iran Maryam Peiravi Former M.Sc Student, Department of Water Sciences and Engineering, College of Agriculture, Isfahan University of Technology, Isfahan, Iran Elham Fazel Najafabadi Assistant Professor, Department of Water Sciences and Engineering. College of Agriculture, Isfahan University of Technology, Isfahan, Iran Journal Article 2025 09 07 Evaporation is a significant climatic phenomenon, particularly in arid and semi-arid regions, where it contributes to considerable water loss from open water bodies such as reservoirs, dams, and agricultural water storage ponds. Efficient management of evaporation is essential to conserve water resources and enhance irrigation sustainability. Although various methods have been proposed to reduce surface water loss, economic feasibility and ease of application remain key factors in their adoption. This study investigates an affordable and practical solution by employing floating cement balls made from low-cost and locally available materials to minimize evaporation from open water surfaces. To evaluate evaporation rates, several empirical models were tested under the climatic conditions of the Zayandeh Rood Dam reservoir. Among them, the Linacre, Ivanov, and DeBruin methods were identified as the most suitable for estimating daily and monthly evaporation in the study area. Additionally, laboratory experiments were conducted using different types of floating concrete balls. The results indicated that floating balls made of perlite, Lika-4-10, and Lika-2-4 reduced evaporation from the tank surface by 33.9, 38.5, and 42.7 percent, respectively. Therefore, Leca 2-4 concrete balls were the most effective, reducing evaporation compared to the uncovered surface. The outcomes of this research suggest that the proposed method offers a cost-effective and scalable approach for reducing evaporation losses, particularly in agricultural ponds and small-scale reservoirs in water-scarce regions Evaporation is a significant climatic phenomenon, particularly in arid and semi-arid regions, where it contributes to considerable water loss from open water bodies such as reservoirs, dams, and agricultural water storage ponds. Efficient management of evaporation is essential to conserve water resources and enhance irrigation sustainability. Although various methods have been proposed to reduce surface water loss, economic feasibility and ease of application remain key factors in their adoption. This study investigates an affordable and practical solution by employing floating cement balls made from low-cost and locally available materials to minimize evaporation from open water surfaces. To evaluate evaporation rates, several empirical models were tested under the climatic conditions of the Zayandeh Rood Dam reservoir. Among them, the Linacre, Ivanov, and DeBruin methods were identified as the most suitable for estimating daily and monthly evaporation in the study area. Additionally, laboratory experiments were conducted using different types of floating concrete balls. The results indicated that floating balls made of perlite, Lika-4-10, and Lika-2-4 reduced evaporation from the tank surface by 33.9, 38.5, and 42.7 percent, respectively. Therefore, Leca 2-4 concrete balls were the most effective, reducing evaporation compared to the uncovered surface. The outcomes of this research suggest that the proposed method offers a cost-effective and scalable approach for reducing evaporation losses, particularly in agricultural ponds and small-scale reservoirs in water-scarce regions https://mmws.uma.ac.ir/article_4110_c5ed4eb5ecccd9ca09b76de0552701c9.pdf