The water evaporation knowledge base
Understand water evaporation — and every practical way to reduce it.
A neutral, cited reference for engineers, water managers, farmers and policymakers: the physics, how to calculate it, its real-world impacts, and a fair comparison of every reduction method — from natural techniques to competing commercial products.
Open water is leaking into the sky
Reservoirs, ponds, irrigation storages and industrial basins lose vast volumes of water to evaporation every year — water that has already been captured, paid for and, often, treated. In arid regions a substantial share of stored water can evaporate annually, and a meaningful fraction of that loss happens at night.
This site explains why it happens, how to estimate it, and how the full range of suppression methods actually compare — honestly, with sources.
6
dominant factors drive the rate
25–40%
of daily loss can occur at night (arid climates)
±10–20%
typical agreement between calculation methods
9+
distinct reduction method classes compared
Start here
The science
What is evaporation?
The physics of the vapour-pressure deficit, the six factors that drive the rate, why depth doesn't change it, and how it's measured.
The methods
How to calculate it
Pan, energy-budget, mass-transfer, Penman-Monteith, Priestley-Taylor and Hargreaves-Samani — with a quick on-site estimator.
The solutions
Methods to reduce it
Natural, chemical and physical methods compared fairly on effectiveness, cost, access, durability and limitations.
Common questions
How much water can evaporate from an open reservoir?
What is the most effective way to reduce reservoir evaporation?
Do floating covers help with algae as well as evaporation?
Go deeper in the Knowledge Hub
Evergreen explainers and current developments in water conservation and evaporation research — each connected to the underlying science.