Due Hydroelectric Project Intake Facility Physical Model Study

CLIENT: HidroAlto S.A.

NHC was selected by HidroAlto S.A. to construct and test a 1:35 scale physical hydraulic model of the Due Hydroelectric diversion spillway and intake facility, located on the Due River in the Province of Sucumbios, Ecuador. The intake facility will withdraw water from the Due River at a design flow of 57.2 m3/s. The civil works of the project will be comprised of a 133.45 m wide diversion weir, with two overflow spillways and six 6.0 m wide gated sluice channels; a four bay intake with sediment excluder; a 4.8 m diameter power tunnel/penstock leading to a 50MW powerhouse; and a fish bypass facility.

The objectives of the model study were to improve and optimize performance of the spillway stilling basin design, flushing of sediments from the reservoir, and minimize vortex activity and sediment ingestion within the intake. NHC evaluated several modifications to the stilling basins and intake to achieve these objectives.

The modifications were recommended within the stilling basin to improve its hydraulic performance and energy dissipation characteristics. Furthermore, the initial design of the sediment excluder sill within the intake was replaced with a "vortex tube” sediment extractor, and vortex breaker pipes were added to dissipate surface vortex activity. Finally, the model was used to develop operating guidelines for the intake and spillway and to assess the reservoir sediment flushing.