Prospects and challenges in integrating reservoir operation in a global surface water dynamic modeling framework

For hundreds of years, humans have altered river flow regimes all over the world with the construction of dams for hydropower generation, water supply, irrigation, navigation, and other reasons. Reservoirs resulting from dams usually have a high impact on the surrounding area by permanently flooding riparian habitat, changing river flow dynamics and soil moisture, disturbing riverine activities and fish migration, imposing the relocation of human settlements, and increasing methane emission due to submerged organic matter. The representation of these anthropogenic activities in numerical models has been the subject of several studies. However, access to reservoir operational data is often limited, preventing us from developing a consistent global scale river flow dynamic model and its physical interactions with the atmosphere and soil.

Recent advances in radar altimetry (RA) data acquisition enable us to accurately monitor reservoirs in regions where distribution to information has long been restricted due to data share policies. In this study, we evaluate the potential of integrating RA data into reservoir operational modeling. Spaceborne remotely sensed data collected by the Envisat radar altimeter (2002-2010), IceSAT GLAS lidar (2003-2009), and daily inflow, outflow and water elevation data collected in situ since 2005 have been analyzed across 28 reservoirs on various Brazilian rivers. Changes in the reservoir surface water elevation from each of these data sources are compared and differences are examined with respect to seasonality and accuracy. A reservoir operation algorithm capable of integrating RA data is presented and evaluated. We discuss prospects and challenges for implementing the algorithm in a global-scale river routing scheme in order to improve our process-level understanding on river dynamics and variability.