PITTSBURGH – The U.S. Army Corps of Engineers Pittsburgh District faced back-to-back high-water events due to heavy rains in April, holding back an estimated six feet of flooding from reaching the Point of Pittsburgh.
Experts from multiple district offices worked together to respond to the historic flooding event, which could have been much more devastating due to historic rain and water levels not seen in 20 years.
Members from emergency management, water management, operations, dam safety, and levee safety offices worked afterhours and on weekends to mitigate flood damage in the region.
Just the previous month, the district had conducted a high-water training exercise in March, which proved valuable leading up to the real-life events of April. District leadership and staff met every morning during heavy rains to anticipate, coordinate and address potential threats to the region’s infrastructure.
“Our preparedness training in March paid enormous dividends during the real-world events of April, and they really demonstrated the importance of being ready and prepared to effectively respond to hazards within the region,” said Albert Coglio, the chief of emergency management.
The Pittsburgh District manages 16 reservoirs built over several decades to hold back water and reduce the damage of catastrophic floods. Since 1938, when the Pittsburgh District built its first of 16 reservoirs, the district prevented more than $14 billion in flood damages to homes, businesses and infrastructure.
During the two high-water events in April, river waters submerged the fountain at Point State Park and shut down several streets downtown, such as the 10th Street Bypass and the I-376 ramp, commonly known as Pittsburgh’s “bathtub.” However, if it hadn’t been for the region’s reservoirs, flood waters would have reached the entire length of Liberty Avenue, a road stretching through more than 25 city blocks.
However, Pittsburgh District’s reservoirs cannot hold unlimited amounts of water, so when they reach their capacity, the district coordinates strategic water releases to limit flooding downstream.
During April’s high-water events, the dam and levee sections used forecasts from water management along with predictions by National Oceanic and Atmospheric Administration to identify which dams, levees and rivers would most likely experience high water.
Along Pittsburgh’s three main rivers, lock and dam operators and mechanics shut down navigation facilities and cleared their areas as river levels rose, while coordinating with the U.S. Coast Guard and the navigation industry to ensure safety for everyone involved.
The Water Management team identified 11 project sites with the potential of reaching a “top five” record pool. The district tracks the five highest pools, outflows, and inflows on record for the history of each reservoir.
“It's not very often that a reservoir reaches a new top five record pool, and it's important to have dam safety staff on site to evaluate the stability of the dam during such high-water conditions,” said Megan Gottlieb, the acting chief of the Reservoir Regulation Section.
Dam safety coordinators traveled to dams with the highest projected risk of flooding. They provided their expertise and extensive project knowledge to managing staff on-site.
The Youghiogheny Dam faced a new third-highest pool of record during April’s rains. The levee safety team established lines of communication with “local sponsors” who manage or maintain levees throughout the district.
The term “local sponsor” is used for towns or other local governments responsible for maintaining flood-protection projects originally built by the Pittsburgh District. Those sponsors provided real-time updates on current project conditions, water levels and flood damage. Levee safety specialists visited project sites that experienced damage or concern due to flooding.
“Unfortunately, seven of our local flood protection projects sustained damages during the April events and are currently being evaluated for emergency rehabilitation in a joint effort between USACE and the local sponsors,” Coglio said.
The Pittsburgh District identified several strengths while working together and with outside partners through April’s flooding events. One of their greatest assets was their strong core of water management, dam and levee safety professionals who have invaluable experience with the region’s watershed characteristics and flood-related infrastructure. The emergency management office trains and prepares year-round for natural disasters, allowing them to respond extremely quickly and decisively. The operations office coordinates navigation notices, locks shut down, and gate operations at dams at 39 facilities in synchronized fashion.
The Water Management team successfully coordinated with project staff, senior leaders, the National Weather Service regarding weather forecasts, and the U.S. Geological Survey for stream gage outages. The team used the latest Corps’ water management software to run twice-daily detailed hourly models of reservoir pool elevations, outflows, and created flood inundation maps. Water Management looked for potential risk, evaluated crest gate operations, and communicated with field staff, engineers, and senior leaders to keep everyone informed as the high-water event progressed.
The district’s dam experts were already trained and aware of dam vulnerabilities based on the previous assessments. Experienced levee personnel had great relationships with the local sponsors, which helped facilitate strong lines of communications. Additionally, the gage data provided by NOAA greatly helped identify what levees were likely to flood. Another strength was the great communication between different sections across the district.
The district also focused on areas where they can improve next time, such as collecting key data before, during and after high-water events to capture a more complete picture of impacts felt in the region over a longer period.
Levee safety is currently collecting track elevation, stage, category, actions from their project’s Emergency Action Plans, and storing their information on a spreadsheet for future reference. Local Sponsors are extremely knowledgeable about their projects. However, local governments experience frequent turnover which can cause a disconnect in critical times.
The Pittsburgh District will consolidate information to share with new sponsors quickly and easily. District staff will also synchronize with local partners to make sure they use reliable weather forecasts and resources to better prepare for future flooding.
April’s high-water events prompted the Pittsburgh District to increase their risk communication with sponsors, emergency response partners and other agencies to continue to safeguard the city of Pittsburgh and its regional communities.