Flooding and utility structures: What you need to know
The strength, size and duration of storms in recent years, as well as the new paths they take, mean that the accuracy of flood maps can constantly be called into question in light of current weather patterns. In the last decade, the US has experienced several extraordinary weather conditions. This means that utility companies are faced with serious challenges in keeping the power on, protecting their facilities, and reinstating services after big storms. While we’ve addressed grid modernization and resiliency measures in previous blog posts, severe weather also poses significant hurdles related to the civil design of utility infrastructure, including substation sites, exposed or enclosed equipment, and secondary oil containment systems.
Last year, Hurricane Harvey had a significant impact on the city of Houston. Hurricane Irma left thousands in Florida and Georgia without power for days. Communities in the Florida Keys lost many homes, and those who were spared spent up to two weeks without water or power. Utility companies understand the devastating impact of these weather events to their clients, and are investing in storm hardening and resiliency programs to protect power supplies and utility infrastructure from flooding.
Flooding is a key issue for many utility companies with the potential for significant impacts on critical components. Utilities in coastal regions face additional challenges due to storm surge, while non-coastal regions are confronted with changing flood patterns caused by development of the areas surrounding them after their site was built.
The first step in developing storm hardening and resiliency mitigation plans is to identify the key components that are the most vulnerable. Thorough facility assessment is necessary to determine whether to modify, retrofit, or redesign in order to keep them safer and make them more resilient.
Flood elevation is critical to this assessment. While base flood elevations should be already mapped, each storm with higher surges or extraordinary conditions can make revisions to maps an ongoing process. Once a component is identified as at-risk based on flood elevation, some utilities choose to keep it as-is but have developed a checklist of activities to perform, putting temporary measures in place when a severe storm is forecast. These proactive steps can protect the power infrastructure from significant damage. If a facility is higher than the flood elevation but is adjacent to a drainage path, riprap or other armoring measures to protect from the effects of flowing water can be used to keep embankments from being washed away.
Other flood hardening steps can include reconfiguring equipment to raise critical components above the flood elevation and building flood defenses in the form of walls and flood drainage systems.
No one solution is ever going to be right for all utility infrastructures, and each site will need to be assessed to see what the effective options are to mitigate for the actual threats it faces. Then the selected options must be designed and implemented. This is the best storm hardening approach a utility company can take.
Leidos helps utilities prepare for the most challenging weather events by evaluating the condition of existing facilities, assessing where improvements need to be made, identifying where infrastructure dollars are best spent, and developing conceptual mitigation plans as part of a storm hardening and resiliency program. Learn more about how we help utilities with our comprehensive Power Delivery Services.