Author(s): Ali Habibzadeh; Brian Hughes; Hernan Barahona

Linked Author(s):

Keywords: Physical model; Spillway; Stilling basin; SSediment flushing; Energy dissipation; Sluice gate

Abstract: The Due Hydroelectric Project is a proposed 50 MW run-of-river hydroelectric project being developed by Hidroalto SA. The project will be located on the Rio Due in Ecuador. The civil works of the intake facility will be comprised of a 133.45 m wide diversion weir, with two overflow spillways and six gated sluice channels; a four bay intake structure with sediment excluder; and, a fish bypass facility. Northwest Hydraulic Consultants (NHC) evaluated the initial design of the Due intake and spillway facilities using a 1:35 Froude-scaled physical model for river discharges ranging from the intake design discharge of 57.2 m3 /s to the 1000-year flood of 2,339 m3 /s. The testing in the physical model revealed some deficiencies in the performance of the initial design of the spillway stilling basins and some opportunities to reduce construction costs. Modifications to the initial design were proposed and evaluated in the model during the design optimization testing phase. The final recommended modifications included: adding a new stilling basin wall separating one of the overflow spillways from adjacent sluice channels; reducing the length of the stilling basin; decreasing the height and thickness of the stilling basin walls; and modifying pier noses to reduce flow disturbances. Furthermore, a sluice gate operation guideline was developed in order to maintain sufficient energy dissipation within the stilling basins for the range of river discharges covered in the study. The physical model was also utilized to evaluate the reservoir sediment flushing procedure and the performance of the intake sediment excluder. Fine sand was used in the model to simulate the reservoir deposits such that qualitative observations of the sediment flushing could be made. Accordingly, a sluice gate operating guideline was developed to maximize the sediment flushing from the reservoir. Finally, the physical model used light-weight sediments to evaluate the efficacy of the intake sediment excluder in trapping sediment to qualitatively observe the sediment load into the intake and the particle trapping process. Modifications to the intake sediment excluder were recommended to improve sediment trapping efficiency and reduce construction costs.

DOI: https://doi.org/10.15142/T3240628160853

Year: 2016