Tybee Island got soaked with 2 feet of rain just this month, just as the island prepares for an $80 million flush via pipes, plants, and reservoirs.
Tybee Island, among Georgia’s first line of defense against storms, has absorbed August’s 2 feet of rain about as best as one can expect from an already-soaked sponge.
“The ground is saturated,” said Tybee Engineer and Director of Infrastructure Peter Gulbronson. Sewer lines are breaking and overflowing; tides and groundwater levels are rising.
The island is even wetter than last year when Hurricane Debby brought about 9 inches of rain over a few days, he added. “Before that storm, we didn’t have continual rainfall, so a lot of that rainfall percolated into the ground.”
While not much more can done to dry the ground for this hurricane season, the city is preparing to bail out the island from future storms and floods with as many buckets as possible.
Two weeks ago, Tybee announced on Facebook that it will begin plans for major stormwater infrastructure updates included in its Stormwater Management Plan, which seeks to invest an estimated $80 million in stormwater maintenance and projects over the next 20 or so years. Integrated with the plan is the 2023 Natural Infrastructure Master Plan developed with the University of Georgia (UGA), which claims that nature-based solutions will alleviate flood load by more than 20%.
“The nature-based plan relies on our pumps and pipes, and our pumps and pipes rely on the nature-based plan,” said Alan Robertson, a consultant and project lead for resilience plans on Tybee.
Stretching Tybee’s stormwater capacity
Tybee Island sticks out from Georgia like the tip of a nose. Unfortunately, it’s among the first coastal communities to get whacked.
“We can’t build to survive a Category 3 direct strike,” said Robertson. “It’s not worth the money.”
Instead, the city’s resilience strategy is to “absorb the blow” and bounce back quicker, said Robertson. “We were off the island for five days in 2016 with Hurricane Matthew. We’re hopeful that the work we do is if Matthew came at us again, maybe we’re back in two days.”
In 2019, the Federal Emergency Management Agency (FEMA) granted the city nearly $190,000 for a Stormwater Master Plan conducted by Thomas & Hutton and completed two years later, said Robertson, which Tybee matched with nearly $63,000. From there, the city developed a list of priorities.
First on the docket is flushing water out of the low-lying south end of Tybee, once home to “marshes and ponds that the city filled in over time,” Robertson explained.
In south Tybee, the city hopes to build a reservoir under the 14th Street parking lot where beachgoers shell out an $8 daily parking fee. “If you can’t stop the water from coming in, then you gotta find a way to get rid of it,” he added. “So, you hold the water there and at a low tide, you pump it out.”
The lot is “the largest area the city has that they could use to have retention,” he added.
Whether Tybee will also retain the funds, however, weighs heavily on Washington’s whims. The Facebook post states that the city will know this fall whether they receive the $10 million Federal Emergency Management Agency (FEMA) grant for the reservoir.
“The future of federal funding is always up in the air,” said Robertson. And about 80% of their plans rely on it.
Waiting for payday
In the meantime, the city will scope out how water will exit the reservoir, likely by replacing an 18-inch stormwater pipe with a quarter mile 54-inch pipe at 15th Street intended to withstand a 10-year storm event—increasing flow capacity nine-fold.
Even if the reservoir project doesn’t come to fruition, directing the neighborhood’s stormwater into a bigger pipe will prevent water from ponding in the street, said Gulbronson. Stormwater pipes are normally up to 48 inches in diameter on Tybee, but about 70% of them are undersized, he estimated.
Again, funding for the pipe is almost secured.
The U.S. EPA obligated $2.6 million to the 15th Street pipe, said Gulbronson, which the city matched with $650,000. But “with the way things are in Washington right now, I don’t have an exact date” on when the city will receive the funds. But once the “final paperwork” is submitted, the project will begin construction in January and finish by late May.
Pipes and Plants
When the 15th Street pipe gets replaced, “we’re going to consider rain gardens and putting nature-based elements on right-of-ways,” said Robertson. It’s just one example of how the city plans on “combining gray with green” in its Natural Infrastructure Master Plan.
Rain gardens in Glenn and Chatham Counties have already shown to perform “really well,” said UGA Stormwater Specialist Jessica Brown. Each of these gardens act as “layer cakes” of native plants, sediments and rocks that percolate water down into the soil, diverting water from overflowing storm drains.
And natural amendments are baked into gray infrastructure itself.
At a culvert on 6th Street, “our plan is to update it to today’s standards: larger, box culvert, bottomless,” wrote Robertson in an email. The three-sided culvert will use the stream bed as its bottom as a more natural passage for fish crossings. Living shorelines will also line the stream’s edges, he added. The culvert is one of several projects funded by a $380,000 grant from the nonprofit National Fish and Wildlife Foundation to promote coastal resilience with nature-based solutions, which the city has matched with $320,000, wrote Robertson.
Further (Not Federal) Funding
As support from Washington continues to be uncertain, the city plows ahead with other cash flows.
Tybee and the Georgia Emergency Management Agency will reapply the $2 million Safe Shelter grant to the city’s Stormwater Management Plan and Natural Infrastructure Master Plan projects; the Georgia Environmental Finance Authority will loan $2.4 million for other key sewer system improvements; and $4.3 million in Special Purpose Local Option Sales Tax 8 funding for stormwater and resiliency infrastructure projects will appear on the November ballot.
“It all depends on money,” stated Robertson. “And grant approvals.”
Jillian Magtoto covers climate change and the environment in coastal Georgia. You can reach her at jmagtoto@gannett.com.