Dams Sector Consequence-Based Top Screen

Revision Date

Considering the large number of assets within the Dams Sector—more than 90,000 dams and more than 100,000 miles of levees—the Dams Sector Consequence-Based Top Screen is a clear and consistent strategy to systematically identify and prioritize critical sector facilities.


The Consequence-Based Top Screen (CTS) methodology identifies the critical facilities within the Dams Sector that have the potential for the greatest impact to their surrounding area in the event of a failure or disruption. These facilities are known as high-consequence facilities. By focusing on potential consequences and separating the analysis from the threat and vulnerability elements of the risk process, the CTS methodology enables the sector to prioritize those high-consequence facilities that need further assessments, additional analysis, and detailed studies, regardless of the hazard. Other benefits include:

  • This process can be especially helpful for an owner responsible for a large portfolio of dams because resources can be focused on the higher priority facilities.
  • In the case of an adversary looking for a target-rich environment, the CTS methodology can effectively reduce the size of the problem by identifying those assets that could potentially attract higher adversarial interest.
  • For the emergency management community, the CTS results can inform them on which facilities should receive additional attention because of their potential for significant impacts at the local and regional levels.
  • In the course of the scenario, the CTS methodology assists in identifying the appropriate contact information to support effective and direct communication in the event of natural hazards, threats, or other urgent notifications.


Using different types of consequence elements, such as human health, economic, and mission disruption, the CTS methodology assumes a reasonable worst-case scenario to measure the potential consequence of a failure from total destruction of or extreme damage to the facility, regardless of whether the event was triggered by a man-made or natural incident. This ensures that the estimates from the CTS will constitute an upper limit to possible outcomes so that the sector can establish a baseline by which to compare different sector assets.

Because this methodology assumes a reasonable worst-case scenario, it does not compound or exacerbate the potential consequences with extreme events, acts of nature, and human error occurring at the same time. It is also 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 man-made incident triggering the worst-case scenario. Additional assessments and study will be needed to ascertain vulnerability, structural integrity, and likelihood of an incident.

The collaborative effort to apply this methodology across the sector plays an essential role in supporting national and sector-wide initiatives for improving the overall protection and resilience of the sector.

Consequence Categories

These are the consequence categories used in the CTS methodology.

Human Impact
  • 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 Contact


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