Dam Safety Review & Flood Study, Newfoundland Power

Dam Safety Review & Flood Study - Tors Cove / Rocky Pond Hydro, Newfoundland Power

Meco completed a dam safety review and flood study for the Tors Cove / Rocky Pond hydroelectric development.

Overall, there were over 30 dams of various shapes and sizes ranging in height from 2.5m up to 15m.  Structure types ranged included earthfill embankments, rockfill embankments, reinforced concrete spillways and gravity dams.

The work includes hydraulic models of inflow hydrology, routing of flows in HEC-RAS and models of dam failure and consequences to establish the consequence classification.

Meco completed the work over a six month period that included the following deliverables:

  • Document Review and models of dam failure to determine the appropriate consequence classification
  • Evaluation of Inflow Hydrology, routing effects, maximum flood levels and freeboard assessments
  • Dam Break Modelling and development of inundation maps for emergency planning
  • Evaluation of incremental consequences of failure models and delineation of potential losses to life safety, environment and economy
  • Site Inspection, Topographic Survey & Staff Interviews
  • Design and Construction Review
    • Freeboard adequacy
    • Spillway Capacity
    • Stability analysis for each dam
  • A condition assessment of the physical properties of each dam through visual observation
  • A comprehensive dam safety review report of the observations and analysis, assessment and conclusions

All models were prepared in the HEC-RAS model software and presented in inundation maps for eventual insertion into the Newfoundland power EPP/ERP format. The work was completed within the project budget and schedule.

Dam Safety Review & Flood Study - Tors Cove / Rocky Pond Hydro, Newfoundland Power
Flood Study & Inudation Mapping

Flood Study & Inundation Mapping, Snare Hydro System, NWT

The Snare Hydro System is located about 144 kilometres north-northwest of Yellowknife, NT on the Lower Snare River.

The system is comprised of a cascade of four (4) hydroelectric power generation facilities; Snare Rapids, Snare Falls, Snare Cascades and Snare Forks, each with a powerhouse and several water control structures including main dam, freeboard dykes, spillway, and intake.

The Lower Snare River stretches 145 kilometres from Big Spruce to Slave Lake from a moderate slope terrain to flat Lakeland.  The only community in the reach is Behchoko, located on Marian Lake.

Meco’s responsibilities included a potential failure modes analysis (PFMA) to define the likely failure modes, models of the failure scenarios to measure the incremental impact on the environment and residents, as well as major infrastructure, and an assessment of the consequences.

Using the results of the analysis, Meco prepared inundation maps for the reach, identifying archeological and cultural sensitive areas, life safety issues and quantified the potential economic losses.

In areas of life safety, the scale of the mapping was reduced so as to better delineate the high risk areas.  Meco also assigned a consequence classification to each dam and established the design criteria for flooding.