Run of River Hydro - Latest Innovations in Diversion Dams and Sediment Exclusion

Run of River Hydro - Latest Innovations in Diversion Dams and Sediment Exclusion

Author: Sam Mottram, Keith Ainsley, Egbert Scherman
Conference: 84th Annual Meeting of International Commission on Large Dams
Date: May 15-20, 2016

ABSTRACT
The exclusion of sediment for hydropower intakes and the flushing of sediment from reservoirs in order to maintain live storage are critical to the long- term viability and sustainability of hydroelectric projects around the World. This paper presents several design innovations and case studies of run-of-river diversion dams and intakes incorporating inflatable rubber dams, vortex de-sanders and Coanda screen intakes for sediment exclusion and flood passage. It presents the findings of physical and CFD model tests, case studies of operating facilities and lessons learned. The projects showcased include:

  • The 147 MW East Toba Hydroelectric Project with inflatable rubber dam for sediment scouring and flood passage.
  • The largest capacity Coanda Screen intake in the World on the 45 MW Kokish River Hydroelectric Project, designed for sediment exclusion and fish passage.
  • Case studies and lessons learned from 8 other run- of- river hydroelectric projects recently constructed that use crest gates (i.e. rubber dams, Obermeyer crest gates or similar) and/or Coanda Screen intakes for sediment flushing and exclusion.

INTRODUCTION
Run-of-river hydroelectric projects typically do not have large storage reservoirs upstream of their intakes, reservoirs that would have sufficient volume and depth to accommodate the exclusion of sediment through settling. Figure 1 below shows the schematic layouts of a typical large hydro storage dam versus a run- of- river hydroelectric facility. A typical run-of-river intake is designed to efficiently divert the hydroelectric project’s generation flow into the water conveyance system and as much as practical eliminate sediment from entering the power facilities. Sediment exclusion for run-of-river intakes has historically been managed using desanding basins, large complex structures that are costly to operate and add significantly to the overall project capital cost.

This paper will illustrate various alternatives to using large desanding basins. These alternatives have proven to be effective at sediment flushing and exclusion, while also being very cost effective and thereby increasing the likelihood of the run-of-river projects being economically viable. Technologies that Knight Piésold have implemented in the design of run-of-river intakes include:

  • Reservoir De-sander Type Intake – using the upstream head pond as the primary sediment settling basin
  • Coanda Screen Type Intake – where a fine screen is used to physically separate sand particles from the diversion flow using the Coanda shear effect
  • Combination of Coanda Screens and Reservoir De-sanding

Several case studies are provided illustrating the application of each technology and the findings of
physical and computer based model testing completed to support each design, as well as the lessons learned from commissioning and operating the facilities.

 

Download the full technical paper.

Download

Perspectivas recientes

Febrero 2024
Empoderamiento y Resiliencia
Enero 2024
Balancing Act: Water Usage Management Vital for a Sustainable Future
Enero 2024
A Difficult Balance Between Engineering, Environmental, Social and Economic Aspects
Noviembre 2023
Knight Piésold Commences with the ESIA for Haib Copper
Noviembre 2023
Insights from the Compilation and Critical Assessment of Breach and Runout Characteristics from Historical Tailings Dam Failures: Implications for Numerical Modelling
Noviembre 2023
Earthquake-induced Deformation Analysis of a TSF Undergoing Tailings Reprocessing
Noviembre 2023
Case Study: Approach to Determining the Risk Mitigation Priority of a Historic TSF in North America
Octubre 2023
Data Management and Insights for Effective Tailings Storage Facility Management
Octubre 2023
The Role of Sensitivity Analysis in Selecting Dam Breach Parameters
Octubre 2023
Influence of Increased Confining Stress on Undrained Behavior of Tailings: A Case History at the Candelaria Mine
Octubre 2023
The Re-use of Existing Bituminous Stabilised Materials for the Rehabilitation of National Route 7 - Case Study
Septiembre 2023
Transición energética para gerentes de mina
Agosto 2023
Interview: Guillermo Barreda, Gerente General, Knight Piésold Perú
Julio 2023
Selection of Soil Shear Strength Parameters Based on Integrated In Situ Tests, Lab Tests and Numerical Calibration Approach
Junio 2023
Leveraging Knowledge and Experience of a Well-Formed Independent Tailings Review Board to Enhance Tailings Facility Safety
Mayo 2023
Is the Implementation of Dry Stacking for Tailings Storage Increasing? A Southern African Perspective
Febrero 2023
Canadian Consulting Engineer's Lifetime Achievement Awards: Jeremy Haile
Febrero 2023
Geotechnical Characterization of Collapsible Salty Sands Subjected to Monotonic and Cyclic Loadings – A Case Study for Areas with High Seismicity
Noviembre 2022
Application of the 3D Limit Equilibrium Method in Tailings Dam Breach Analysis
Noviembre 2022
Evaluation of Tailings Behaviour for Dam Breach Assessment