The Technical Bulletin for Classification and Inflow Design Flood Criteria (OMNRF, 2011) and the CDA guidelines (2007) outline the requirements for the classification of dams. In Ontario, dams are classified using the Hazard Potential Classification (HPC) system, which categorizes dams according to the potential hazards presented by the dam. The HPC assesses the greatest incremental consequences that could result from an uncontrolled release of the reservoir (i.e. breach of a dam). It is not a measure of the condition of the dam or the risk of failure. Incremental losses are assessed with respect to life, property, and environmental and cultural-built heritage. The Inflow Design Flood (IDF) is the most severe inflow flood for which a dam and its associated structures are designed. All reconstructed dams are required to meet the OMNRF (2011) and/or the CDA (2007) guidelines with respect to the IDF.

First, a hydrologic assessment is used to estimate the rate of flow for floods of varying magnitudes for the dam. Next, a hydraulic assessment is used to determine the flood handling capability of the dam and its associated structures when subjected to these floods. We then conduct an analysis based on the incremental consequences resulting from the dam breach over and above those consequences that would have occurred had the subject dam not failed. This includes a thorough assessment of the consequences of dam failure under flood conditions. Once this is completed, we then reference the appropriate guidelines and documents to determine the HPC of the structures and the required minimum IDF. These assessments are based on measured and estimated parameters that effectively define the hydrologic and hydraulic characteristics of the river basin.

Aqua Geomatics is an experienced provider of both hydrology and hydraulic analyses specific for river systems with the associated dam structures. Once these assessments are made, we can then determine the HPC and IDF for the dam based on OMNRF (2011) and/or CDA (2007).

Our services include:

  • Hydrologic Analysis 
  • Hydraulic Analysis 
  • Modeling breach scenarios
  • Incremental consequence assessment
  • Hazard Potential Classification based on respective guidelines
  • Use of state-of-the-art GIS technology based on layers
  • Inflow Design Flood determination
  • Mitigation measures