The functionality of hydrological information systems is to manage hydrologicaldata. Several types of hydrological data stored in the database include rainfall,evaporation, river flow and water quality. The goal of this research is to designa hydrological data model that integrates with a geographic information system(GIS) data model. The integrated data model will support the management of thehydrologic data. Two types of data that will be considered are spatial and non- spatial data. Spatial data focuses on space and location (i.e. point,line and polygon) whereas non-spatial data is related to information attributes(i.e. value of water quality, name of the water quality station). These storeddata are also related to time. The authors add a time constraint to themodel so as to give greater flexibility in hydrological analysis. The data modelis developed using a feature-based approach that binds the model on spatial andnon-spatial data to a single architecture. Four fields using this approach willbe considered: geographic entity; geometric entity; graphic display; and, timeentity. In this architecture, a "cube" system will be used. It is based on threecoordinates (What, When and Where). The authors propose the integration willinclude a time constraint using a double cube data model based on a feature-basedmodel. A unique key is used to access the integrated database. Includes 11 references, figures.