Use of MODIS images to monitor the sediment inflow into the Tres Marias reservoir

This study presents the monitoring of the sediment discharge from the Indaia River into the Tres Marias reservoir, based on the use of satellite images. A 12-year time series of MODIS 8-day image composites (Terra and Aqua on-board sensors) was used in this study. Estimates of the water surface reflectance were calculated using the algorithm MOD3R. River suspended sediment discharge records made available from the CEMIG hydroelectric company were integrated in the analysis to understand the variability of the remote sensing reflectance. The results showed a strong relationship between the reflectance data and the Indaia river solid discharge. A strong variation of the reflectance is assessed within the reservoir (upstream towards downstream), with high reflectance values upstream (near the river mouth) and low reflectance values downstream. The estimated percentage of valid records in MODIS images met the requirements for monitoring the flow of sediment. Estimates of water reflectance show great potential in relating the sedimentation processes within the Reservoir as a function of time.