How rising groundwater caused by climate change is destroying coastal communities

“In the Bay Area, due to military use and the technological boom in Silicon Valley, there is a lot of legacy pollution underground – it leaves a lot of nasty things,” said Kris May, a coastal engineer and climate scientist who founded the Pathways Climate Institute. “And it often happens that after we reset low-income houses in these areas, we repair them. But they still leave a certain amount of pollutants underground, and these regulations are based on non-rising groundwater levels.”

The water table is now rising. When it does so, it saturates the soil and releases pollutants such as benzene. These chemicals are extremely volatile, and as gases, they can easily enter the home through the sewer.

This is the effect of rising groundwater on a system-sewage. But it may affect more. Buried wires that are not properly sealed will short-circuit; the foundation will start to rise from pressure. Some people worry that the earthquake fault may even be stressed.

How does water find its way out

To protect themselves from rising sea levels, cities are turning to the same tools they have used for centuries: dams and seawalls. Boston proposed a 175-mile seawall called the Haimen Project. Miami proposes to build a $6 billion, 20-foot-high seawall. New York proposed its own $119 billion, 6-mile project called the New York Harbor Storm Surge Barrier. Homeowners from Florida to California are setting up barriers to prevent the ocean from entering. But the fundamental problem with all these interventions is the same: the sea wall blocks the sea, not the groundwater.

In some areas, if the underlying ground is relatively impermeable, sea dikes or flood dikes can be built to slow the rise of groundwater. But then you will encounter other problems. Recall that the water flows to the ocean. A barrier that prevents groundwater from rising with sea level will also prevent rainwater, such as the recent rain from flowing into the sea.

“If you don’t let the water flow into the ocean, then you basically have to pump it through the wall. This is basically what the Netherlands has been doing for centuries,” said Rozell of Stony Brook. But it also creates problems, because many of the places these seawalls are trying to save—most of Lower Manhattan, most of San Francisco and Boston—are built in wetlands, landfills, or both. Of. “If they pump water, the land will sink,” Hill said.

Even if the city is willing to follow this path, it may not be possible everywhere. Fletcher of the University of Hawaii said: “In many cases, you can pump water all day and the groundwater level will not drop.”

Recall that groundwater is water that enters spaces or pores in sediments. In some places, such as Miami, “the pores are so big that you can only suck in water from the mouth of the river from the ocean,” Fletcher said. “You can pump water as you like, it just keeps pouring in from the endless body of water”-the sea.