Spatiotemporal hierarchical models to assess the influence of climate, land use and hydrology on water quality in Itaipu Reservoir – Brazil

The process of eutrophication at reservoirs is different from lakes mostly because of the occurrence of tributaries arms enhance reservoir’s connectivity with the watershed they are constructed. Tropical reservoirs have different response for the force forcings acting at the system; therefore, the drivers of eutrophication at tropical environments are also different. Our purpose here was to evaluate how climate, land use and hydrology interact with chlorophyll-a, algal bloom area and macrophyte area through spatiotemporal hierarchical linear mixed model. To assess this, we used data from Itaipu Hydroeletric PowerPlant monitoring program from 1985-2020 of three tributaries arms. Our findings suggest that the water level of the reservoir can be a important driver for eutrophication within a level of influence of -0,41 for algal bloom and -0,31 for macrophyte. Urban area and cropland area also showed an interest level of influence on water quality, highlighting the connection of tributaries with the watershed.