Lionel Zawadzki (CLS, France); Clément Lacrouts (CLS, France); Pierre Thibaut (CLS, France); Gérald Dibarboure (CLS, France)

By their essential role in the world's ecology system, rivers and lakes have always been of major importance for the world's population. With the increasing demography, fresh water is a more and more pressured resource for the population needs as well as a societal risk for local populations. It is also a fundamental element for industry and agriculture, therefore becoming an economic and political stake. Rivers and lakes monitoring is thus indispensable but still remains a challenge because of the limited accessibility to upstream regions, the scarce repartition of in situ gauges and the limited dissemination of their measurements.
Though the quality of their measurements over hydrological areas is significantly lower than over oceans, the existing altimetry data, allows a massive live and historical access to a wide network of information.
We developed an algorithmic approach to produce an as exhaustive as possible database of Water Surface Height (WSH) virtual gauges combining the SRTM land/water mask and high-resolution altimetry. Assessing the quality of our database and providing WSH uncertainty estimations is a major concern, we therefore propose a methodology to edit and validate these numerous records based on intra-mission, inter-mission and in situ comparisons.