A large Dutch consortium has joined in the project “Dutch network on small spaceborne radar instruments and applications (NL-RIA)”, led by TU Delft. The objective is to bundle the radar-related knowhow available in The Netherlands, and fill the knowledge gaps, in order to boost SmallSat radar-based Earth Observation technology. The task of FutureWater in this project is to study challenges and requirements for applications of altimeter data for water resources assessments. This report presents a short literature review, existing databases that are currently used for this type of studies, two case studies performed by FutureWater in which altimetry data was used. Based on these case studies in the final chapter, a few recommendations and requirements are put forward on revisit frequency and accuracy for the design of an altimetry mission.