Melissa is an application for the off-line validation of water level (stage) data in rivers and tidal data in the Dutch coastal area. The software is used for visualization and model-based validation, and contains a model that predicts water levels for one location based on data from surrounding detectors. This model is also exported to the national system that is used for on-line monitoring.

Maria is an application for acceptance, validation and processing of hydrographic data. The Dutch government has commissioned acquisition of hydrographic data to commercial partners. These partners make available raw data. Rijkswaterstaat adds meta information to these data, and applies standardized checks and validation steps using the Maria software package. Maria is also used as an intermediate to other software components used by Rijkswaterstaat. Examples are the computation of coastal profiles using the interpolation software Digipol and the simulation of waves nearshore (SWAN).