The hidden rise of sea level costs

They're mostly below the surface.

Not long ago Buddy and I decided we needed to learn to kayak. Here we are, me doing the propulsion and Buddy handling the navigation.

Why learn to paddle? In 2012, Superstorm Sandy pushed enough of the Atlantic Ocean into Newport Harbor to cover Bowen’s Wharf more than a foot deep. The wharf is a tourist and shopping area - a feature in Buddy’s morning walk.

During the flood - which simulated sea level rise several decades in the future - a kayaker paddled around among the wharf’s 14 shops, 9 dining places, and 2 art galleries, and a reporter took an unforgettable photo that woke a lot of people up.

Now Buddy and I have learned to paddle. When climate change boosts the sea level in Newport, we’ll be ready.

Well . . . maybe not.

For one thing, most of us think water in our streets and basements is the primary effect of sea level rise. Hurricane Sandy gave us a taste of this, but it will be many years before Bowen’s Wharf is covered regularly in salt water. And long before then, rising water will have destroyed other important infrastructure in our city - without our noticing anything as dramatic as a flood.

Here’s just one of the many sea level rise (SLR) threats to Newport - and hundreds of other coastal towns. We’ll discuss the other threats in coming letters.

OUR SEWAGE SYSTEM
City sewers were hit by a big rainstorm just last September, getting the attention of Newport City Hall. In one Council meeting,

A dozen hands shot up when his wife, Maureen, asked the crowd, “How many of you have had five feet of sewage in your basement? . . . “We have sewage, we have toilet paper coming up through our washing machine,” she said. “It’s not just water. It’s not just a hurricane. It’s a sewer system that you passed … that is destroying us.” [Newport This Week]

Part of the problem is that pipes bring both treated sewage and rainwater to the harborside. Heavy rain or snowmelt, combined with a particularly high tide (the same effect as sea level rise) puts backpressure on the city’s pipes. Unable to drain properly, street runoff and sewage mix and escape into low-lying homes, yards, streets, and the harbor.

In the past decade, Newport has spent between $21 and $63 million (depending on who’s counting) to repair combined sewer overflows (CSOs), separating our surface water drainage and sewage pipes. Nearly 860 other municipalities across the country have faced or still face this costly upgrade. It’s not a choice; it’s enforced with heavy fines by the EPA.

To help reduce the backpressure from seawater, in 2019 the city constructed a ‘tidal gate’ across a 4-foot diameter storm drain. It’s out of sight under one of Buddy’s favorite waterside playgrounds.

The tidal gate will help prevent the influx of water into the City's stormwater system, which in recent years has seen an increase in the number of tide-related flooding events. [City of Newport]

The city is looking ahead to two more million-dollar storm drains elsewhere on the waterfront. In Newport, we’re lucky. Not all coastal towns are going to find the money to deal with these problems (see our recent letter).

Household septic systems are under even more pressure than municipal systems. When a toilet is flushed, the waste is supposed to go into an underground tank, then drain down into the soil where microbes process it before it seeps further down into the water table. But sea level rise is beginning to change the height of the water table in many places. As groundwater rises, the septic system process fails, and the waste overflows.

Take North Carolina for example.

The study found that heavy rainfall, temperature and sea level - expressed as a day’s highest tide - all had significant effects on 90% of the wastewater treatment systems in coastal North Carolina.

In the long run, sea level rise is going to overrun all of this. I think if we’re going to live on the coast for any length of time, sewer systems are going to let us down and septic systems are going to fail. They already are. [Lawrence Cahoon, biology professor at UNC and co-author of the study]

Sea levels aren’t high yet, but the occasional king tide and storm surge today are simulating the threats our families and our wallets will face daily in the near future. In our next letter: more really big costs from sea level rise that few people know about.

Yes, our kayak can keep Buddy and me up on the water’s surface, no matter how much it rises. But while we’re safe there, below the surface unseen rising waters are doing far more damage to our city. And incurring big near-term tax and rate costs that residents are having to pay.

What can we do about it? Start by electing forward-thinking town leaders who really understand the problem. You may have to help recruit and educate them, campaign for them, and support them at their meetings. But without the right people in City Hall, we’re stuck! More about this in an upcoming letter.

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LEARN, THINK, ACT

• Yes, we can get a forecast of surface flooding in our area from sea level rise. It can help us understand the long-term threats to property values and neighborhood attractiveness. But the SLR maps don’t let us see the far more costly hidden damage under the surface.

• That sewage horror story in Newport. Please add a Comment below if you have other stories - or anything else you want to add!

• The unforgettable photo that set Buddy and me learning to kayak.

• We can read about Newport’s first tidal gate.

• Threats by sea level rise to coastal groundwater supplies all along the East Coast.

• Study of North Carolina coastal systems.

• Are we too negative for some readers? We write about ‘costs’, ‘dangers’, ‘threats’ a lot. Many of these threats can be moderated by locally, and we try to point out actions to do this. But there are many costs that Buddy and I are learning can’t be dodged, no matter how well a community comes together to fight them. We hope, however, that readers also know that most of these ‘threats’ are avoidable, and millions of families will avoid them - by moving. There are relatively ‘climate-proof’ towns all across the country - many of them. We’ll write about how to identify these towns in coming letters.