Dams Sector Consequence-Based Top Screen

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The Dams Sector Consequence-Based Top Screen (CTS) Methodology is a clear and consistent strategy to systematically identify and prioritize dam facilities within a given portfolio.

The CTS identifies critical, high-consequence facilities whose failure or disruption are associated with the highest possible impacts when compared to other facilities within the portfolio. By focusing on potential consequences and separating the analysis from the threat and vulnerability components of the risk process, the CTS allows the user to prioritize facilities, regardless of the hazard, to inform and support decisions regarding additional analysis and detailed studies.


The CTS focuses on potential consequences and separates the analysis from the threat and vulnerability elements of the risk process, which enables the user to prioritize those high-consequence facilities that need further assessments, additional analysis, and detailed studies, regardless of the hazard. This same prioritization can assist owners in focusing resources on higher-priority facilities, or informing emergency management personnel about facilities in their jurisdiction that may require additional attention or resources.

By using metrics that cover a range of potential values, the CTS is scalable and can be effectively implemented at different portfolio levels (owner, state, regional, and national) by adopting consequence thresholds that appropriately represent the corresponding scope under consideration.


Using three types of consequence elements—human impacts, economic impacts, and impacts on critical functions—as well as screening criteria and weighting criteria, the CTS methodology assumes a worst reasonable case scenario to measure the potential consequence of a failure from total destruction or extreme damage to a facility, regardless of whether the event was triggered by a human-caused or natural incident. This ensures that the estimates from the CTS will constitute an upper limit to the potential impacts associated with failure, severe damage, or disruption to the facility, regardless of the triggering event.

The worst reasonable case scenario represents a condition of total or extremely severe damage to the facility keeping in mind that the situation is not simultaneously compounded or exacerbated by concurrent extreme events, acts of nature, or human error. It is important to note that the screening criteria do not consider the structural condition or vulnerability of the facility, nor do they address the likelihood of the natural hazard or human-caused incident triggering the worst reasonable case scenario. Additional assessments and study will be needed to ascertain vulnerability, structural integrity, and likelihood of an incident.

Consequence Categories

The consequence categories used in the CTS methodology are as follows:

Human Impact
  • Total Population at Risk (PAR)
  • PAR 0-3 miles from toe of the dam
  • PAR 3-7 miles from toe of the dam
  • PAR 7-15 miles from toe of the dam
  • PAR 15-60 miles from toe of the dam
Economic Impact
  • Asset Replacement Value
  • Remediation Cost
  • Business Interruption
Impact on Critical Functions
  • Water Supply
  • Irrigation
  • Hydropower Generation
  • Flood Damage Reduction
  • Navigation
  • Recreation

Dams sector CTS application tool 


For additional information on the Dams Sector Consequence-Based Top Screen, contact the Dams Sector Management Team at