US flag signifying that this is a United States Federal Government website   Official website of the Department of Homeland Security

Homeland Security

Dams Sector Consequence-Based Top Screen

Dams Sector Consequence-Based Top Screen

Considering the large number of assets within the Dams Sector, a clear and consistent strategy is required to systematically prioritize and identify a sub-set of high consequence facilities.


The Consequence-Based Top Screen (CTS) methodology identifies critical facilities within the Dams Sector. Critical facilities are those whose - failure or disruption could be potentially associated with the highest possible impact among sector assets. By focusing on potential consequences and separating the analysis from the threat and vulnerability elements of the risk process, the CTS approach is an effective all-hazards start to prioritizing facilities.

In the case of human threats represented by an intelligent and adaptive adversary, it would be nearly impossible to conduct in-depth vulnerability evaluations of all assets in a target-rich environment such as the Dams Sector. In this case, the CTS approach can effectively reduce the size of the problem by identifying those assets that could potentially attract higher adversarial interest.

The prioritization information obtained from the CTS process can support decisions regarding the need for additional analyses and detailed studies. For example, in the case of an owner responsible for a large portfolio of dams, those facilities identified as high-consequence assets through the CTS process could be assigned a higher priority for conducting detailed risk assessments. Results from the CTS process also effectively inform decision-makers about facilities that should receive additional attention from the emergency management community because of their potential for significant impacts at the local and regional levels.

CTS Implementation

  • The CTS methodology is supported by a user-friendly, Web-based tool that allows users to consider different consequence categories.The analysis is based on a "worst reasonable case scenario," which represents a condition of total or extremely severe damage to the facility, but also considering that the situation is not simultaneously compounded or exacerbated by concurrent extreme events, freak acts of nature, or human error.
  • 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 manmade incident triggering the worst reasonable case scenario. Therefore, the resulting consequence estimates should constitute a reasonable upper limit to the potential impacts associated with severe damage or disruption to the facility, regardless of the triggering event.
  • Effective implementation of the CTS methodology allows the Dams Sector to establish a common baseline to consistently measure different types of consequence elements (e.g., human health, economic, and mission disruption), leading to a sector-wide prioritization framework that facilitates comparison of consequence information within the sector. It also assists in identifying the appropriate contact information for critical facilities to support effective and direct communication in case of natural hazards, threat stream data, or other urgent notifications.
  • This Dams Sector collaborative effort plays an essential role in supporting national and sector-wide initiatives for improving the overall protection and resilience of the sector.

CTS Consequence Categories

Human Impact

• Total population at risk within flood scenario inundation zone
• Population at risk within 0 and 3 miles from the toe of the dam
• Population at risk within 3 and 7 miles from the toe of the dam
• Population at risk within 7 and 15 miles from the toe of the dam
• Population at risk within 15 and 60 miles from the 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
• Flood Recreation


For more information on the Dams Sector Consequence-Based Top Screen, contact

Last Published Date: April 14, 2015
Back to Top