 This is the IAEA's Isotope Hydrology Lab. It's based in Vienna, Austria, but the work conducted here helps countries all over the world protect and preserve their water supplies. We need water for industry, we need water for humans, we need water for the environment. Less than 3% of Earth's water is fresh water. It's available in lakes, rivers, aquifers and locked away in glaciers and ice caps. It's also difficult to find, underground water is our biggest source of fresh water. The water that you see in rain, in lakes, in rivers, that is a fresh water but that is the annually renewable water. It is a very small percentage of all water that is available on Earth because most of that water that we can use is underground in aquifers. Isotope hydrology is used to gain vital information about fresh water such as its origin, age, quality and renewable rate. With such knowledge, countries can manage their water resources better and locate safe drinking water, even deep underground. Managing and protecting water resources worldwide, we need to have a sound understanding of how water exists and flows in the world, in the ground. And for that, isotopes are a critical piece of technology that we need to use to be able to achieve that. Isotope hydrology is an important tool to make sure growing populations have access to safe and sufficient water. From Vienna, Austria, this is Alexandra Anapanich reporting for the IAEA.