Water Resource Management — A Methodology for Estimating Volume Calculation of Water Bodies with Earth Observation Data and Space Analysis

The efficient monitoring of existing Water Plans (PA) in the geographical area of jurisdiction of the Administration of the Tagus and Ribeiras do Oeste Hydrographic Region (ARHTO), as well as the management of existing water resources (HR), involves the efficient characterisation of water availability of reservoirs, reservoirs and dams. The extraction of geospatial information through Earth Observation (OT) images acquired by the Sentinel-2 (S2) mission, which provide a huge volume of data almost in real time and in extensive areas of the territory, showed to be differentiating for updating the characterisation of water reservoirs in the form of small and medium dams existing in the region of artho, namely their location and delimitation to the Full Storage Level (NPA) of the PA, according to the methodology proposed in (Patriarca et al., 2021). These results showed promise for the study and management of existing pressures on HR resulting from phenomena such as increasingly frequent droughts and water scarcity in reservoirs and reservoirs with an impact particularly on irrigation agriculture. The methodology studied in ESRI ArcGIS © environment aimed to develop an operational approach to HR management of the territory of Continental Portugal in the area of jurisdiction of ARHTO. The approached methodology is divided into two components: the inventory and characterisation of BPs by NPA based on OT data (phase 1) and the determination of reservoir volume using geospatial data spatial analysis techniques (phase 2). The estimation of volumes of Water Bodies (CA) identified in the ARHTO study area was tested with some case studies such as the examples of Meimoa and Marateca reservoirs. The availability of geometrical vector information at 1:25000 scale was used to obtain Triangulated Irregular Network (TIN) models and Digital Land Models (MDT). Based on the obtained MDT, using spatial analysis and interpolation techniques, the volume values of the CA under study were determined.