Recent estimates suggest that there are over 16.5 million small water reservoirs (less than 0.1 km²) worldwide. The number of water reservoirs larger than 0.1 km² has exceeded 76,000. These reservoirs are designed for local water storage with storage capacity exceeding 7,200 km³. They play pivotal roles, especially in water-stressed regions of the world, in meeting local water demands, maintaining food security, supporting business owners, and contributing to social stability, labor market, local climate, and ecosystem health. However, evaporative losses from these reservoirs are often overlooked in water budgeting influencing their storage efficiency and may exacerbate conflicts over shared water resources.
Accurate prediction of the evaporation from these reservoirs is a grand challenge due to the complex coupling between atmospheric conditions and the inherent characteristics of reservoirs. This commonly leads to modelling efforts relying heavily on adjusting parameters which could potentially mask the true physics controlling the evaporation process. To address this gap, we model evaporation dynamics and surface fluxes from small reservoirs (and lakes) that are located in different climatic zones all over the world. Our energy-constrained theoretical model investigates reservoir characteristics and atmospheric forcing parameters (e.g., wind, radiation, and air temperature) to obtain energy storage of the water body, surface heat fluxes, and vapor exchanges with overlying air. The research will provide a physically-based framework to quantify the extent of evaporative water loss under different climate scenarios.
Check out one of our recent papers on this topic for further details:
Aminzadeh, M., Friedrich, N., Narayanaswamy, S.G., Madani, M. Shokri, N. (2024). Evaporation loss from small agricultural reservoirs: An overlooked component of water accounting, Earth’s Future, 12, e2023EF004050. https://doi.org/10.1029/2023EF004050