Data Integration for Investigating Drivers ofWater Quality Variability in the Banja Reservoir Watershed

It is increasingly important to know the water quality of a reservoir, given the prospect of an
environment poor in water reserves, which are based on intense and short-lived precipitation events.
In this work, vegetation indices (NDVI, EVI) and bio-physical parameters of the vegetation (LAI, FC),
meteorological variables, and hydrological data are considered as possible drivers of the spatial and
temporal variability of water quality (WQ) of the Banja reservoir (Albania). Sentinel-2 and Landsat
8/9 images are analyzed to derive WQ parameters and vegetation properties, while the HYPE model
provides hydrological variables. Timeseries of the considered variables are examined using graphical
and statistical methods and correlations among the variables are computed for a five-year period
(2016–2022). The added-value of integrating earth observation derived data is demonstrated in the
analysis of specific time periods or precipitation events. Significant positive correlations are found
between water turbidity and hydrological parameters such as river discharge or runoff (0.55 and
0.40, respectively), while negative correlations are found between water turbidity and vegetation
descriptors (􀀀0.48 to 􀀀0.56). The possibility of having easy-to-use tools (e.g., web portal) for the
analysis of multi-source data in an interactive way, facilitates the planning of hydroelectric plants
management operations.