This research attempts to answer the following questions: Is it possible to use the space altimetry radar to distribute the flow within Rio Negro Basin? Further, is it possible to apply the developed methodologies to a poorly gauged basin such as the Caqueta Basin in the Colombian Amazon? In this study we present how to build a time series of water height at virtual stations (intersection between a satellite track and water) from Topex/Poseidon and ENVISAT radar missions measurements. A hydrodynamic model allows propagating the flows at virtual stations from in-situ measurements of some gauged stations. A rating-curve (stage/discharge relationship) can be estimated at these virtual stations, expanding in-situ measurements and hydrological network. Moreover, this information has been used to determine physical parameters such as the average water depth at each cross section, the bottom slope and the Manning roughness coefficient. The introduction of 21 and 11 virtual stations respectively over the Rio Negro and Caqueta main streams, defines watersheds 10 times smaller than those delimitated from in-situ stations, and for which we can now estimate the discharge from space.
