This project investigates new processing algorithm of nadir- and swath-altimeter data to construct a coastal altimeter database in the time interval from 2016 to 2026 and to derive water level and significant wave height in the Baltic region. These new products are then merged and processed to investigate dynamical processes in the water flow at the coastal boundary and long-term changes in water level. On sea, we construct two dimensional daily grids of anomalies above a mean sea surface and derive coastal and estuarine water level and currents. On land, we estimate river discharge and water storage change in estuaries and inland water bodies. The final products are time-series and grids of geophysical quantities that have potential application for vertical land motion studies and changes in the water cycle. We explore key scientific questions: (1) what improvement the merging of SWOT and nadir altimetry brings; (2) what the spectral content of the derived ocean mesoscale is, (3) is the interaction of river discharge and coastal level observable, (4) can we detect changes due to climate change and humans. To address the above key scientific questions, we implement a processing pipeline from Level 1 and Level 2 Fully Focused and Unfocused processing to the daily Level 4 grids construction and river discharge and storage estimation. Three sub-projects are distinguished with three sub-schemes: the altimeter processing part (SMAP-SAMP for FF-SAR processing and retracking) , the Optimal Interpolation mapping (OI) and the Discharge and Storage change Algorithms (DAWG). The use of C3SE resources for parallel execution is motivated by the computation load of each of the three schemes. The data volume of the global multi-mission Level 1 AT and of the Level 2/Level 3 SWOT data is huge, more than 40 TB. We will select the data for our region and store only in-situ input, Level 2 in-house and external nadir-altimetry and the SWOT intermediate and final data.