Numerical investigation of 2D/3D hydrodynamic conditions in the proximity of a bridge in an amazonian river

The Nanay Bridge, Peru's largest bridge, is located on the Nanay Rive near its mouth to the Amazon River in the city of Iquitos, connecting different communities. The Nanay Bridge is 2,283.50 m long and 14.80 m wide. The construction of this structure was completed in November 2021, ensuring, and improving transportation. This research is aimed to the numerical investigation of the hydrodynamic conditions in an Amazonian River reach (Nanay) and is interaction with the mentioned bridge. To this end, The IRIC Nays CUBE and HEC-RAS models were used to simulate unsteady fully two and three-dimensional flow with non-hydrostatic water pressure and high vertical accelerations and velocities. It allows to represent the flow characteristics on the different piers as well as the water level at a certain lateral distance. Different experiments using mean, minimum and maximum flows for different return periods were conducted. Field ADCP and flow measurement data was used for characterization and validation purposes. Estimations of scour around the piers were carried out to quantify the impact of different flows in these elements. The three-dimensional flow structure plays an important role for determining the appropriate countermeasures for local scouring and protection. Our simulation results show that two and three-dimensional flow patterns match the conceptual model of river flow in this type of water courses. Our findings provide useful insight to verify the impact that the implantation of different infrastructures around the Amazonian water courses could produce. This contribution is pointed to be a support in river engineering in Amazonian rivers and might be more valuable in conjunction with physical hydraulic model investigation.