In 2017, Hurricane Harvey swamped the Houston area, flooding sewage treatment plants that were forced to temporarily shut down.
It was a wake-up call for the Hampton Roads Sanitation District, said John J. Dano, chief of planning and analysis.
“We started asking ourselves the question, ‘how would we respond to a catastrophic event like that?’” he said. “We hadn’t gone through the exercise of understanding what that would look like for our area.”
A new climate plan is their attempt to do that.
It lays out the substantial risk that flooding from sea level rise and coastal storms poses to the pipes, pumps and plants that control the region’s sewage.
Climate change “undermines HRSD’s ability to convey and treat wastewater to protect public health and the environment,” officials wrote.
Some infrastructure is newer, while other parts date back to the 1940s when HRSD was created, Dano said.
The district serves 20 cities and counties, including the Eastern Shore. The sprawling system includes 16 treatment plants, more than 100 pump stations and more than 500 miles of pipe.
For the new analysis, the district looked at how more than 130 key facilities would fare through the end of the century in the face of flooding threats.
Assessing the risk was a challenge because of differing or a lack of information across the wide service area, officials said. HRSD invested in its own flood modeling.
They found that about half of the key facilities are at risk of some form of flooding in the coming decades. A majority of those are pump stations located in neighborhoods throughout the region.
Future damages would go beyond just service disruption, Dano said.
“If our facilities are down, there’s the potential for raw sewage to be running into our local waterways and people coming into contact with that,” he said.
“If our treatment plant’s working but the local pump stations in the community aren’t working, there’s still a problem.”
HRSD estimates the current flood risk in any given year is about $6 million in 2020 dollars.
Because of climate change, that could more than triple by 2060 and increase by a factor of 20 by the end of the century, according to the analysis.
Dano said the district is now working to figure out how its money can best be spent to prepare for flooding impacts.
That will likely include elevating equipment, building barriers like small floodwalls and levees and “waterproofing” structures.
In some cases, HRSD may have to relocate its facilities.
“We want to make sure that we're not protecting something that might be no longer needed,” Dano said.
