Category: Water

Protecting Coastal Cities, Q&A with EarthTalk

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What have we learned from storms like Katrina, Sandy and Harvey about protecting our coastal cities better from the warming-intensified major storms hitting them?
–Mitch Wyndam, Burlington, VT

Major storms like Katrina, Sandy and Harvey were devastating to local populations and reformed the landscapes of the regions where they made landfall. They also changed the way we think about—and design—our coastal cities. Let’s hope we’ve learned about where (and where not) to site habitable buildings as well as the importance of maintaining—even expanding—natural buffers that protect the places where people live from unnecessary property damage and/or loss of life.

New York City has gotten busy bolstering itself against future “super storms” like 2012’s Sandy. Code changes like requiring electrical transformers to be in the upper floors (not basements) of commercial buildings, and developing feasible strategies for shuttering tunnels, airports and subways, are just a few of the changes wrought by Sandy.

Developing resilient infrastructure is another way that city planners are hoping to mitigate future flooding issues, like at the recently opened Hunter’s Point South Park along the East River in Queens. One especially climate-resilient feature of this park is a big playfield made of synthetic turf that can “detain” a half million gallons of water when the East River overflows during a high tide or storm surge. When the tide goes back out—or the storm moves on—the detained water is slowly released back into the river through a network of exfiltration channels hidden beneath landscape features. An outer wall protects natural barrier marshes that filter water and can also absorb and detain more stormwater as needed.

One especially climate-resilient feature of NYC’s new Hunter’s Point South Park is a big playfield made of the synthetic turf that can “detain” a half-million gallons of water when the East River overflows during high tide or storm surge. Credit: NYC Parks.

It was surprising just how walloped New Orleans was by Hurricane Katrina in 2005, given that the city’s leaders and residents were used to regular flooding during storm events. But the damage, displacement and loss of life from this “100-year-storm” event spurred long overdue efforts to bolster the city’s defenses against floodwaters—including efforts to conserve and expand outer marshlands which serve as buffers against storm surges and flooding.

New Orleans also bolstered its infrastructure and capacity to handle flood waters. “Given similar evacuation conditions to those seen in Katrina, the [new] system is expected to reduce potential loss of life by as much as 86 percent without pumping and up to 97 percent with 50 percent pumping for a 100-year flood event,” reports Wolfgang Kron of insurance giant Munich Re. He adds that New Orleans’ post-Katrina flood mitigation system should reduce property damage by 90 percent for a 100-year flood event and 75 percent for a 500-year event, compared to the pre-Katrina situation. While New Orleans hasn’t been tested on such a major scale since Katrina, everyone is hoping the projections bear out when the next major storm hits.

As for lessons learned from 2016’s Hurricane Harvey, it’s too soon to tell, as many Houston-area residents are still in recovery mode. But no doubt some of the lessons from Katrina and Sandy will be applied in Houston and other coastal cities around the world getting ready for rising sea levels and more extreme flooding and storm surges as global warming heats things up.

CONTACTS: Hunter’s Point South Park; Munich Re.

                                                                                                      

Transforming Air Into Pure Drinking Water Is Finally Possible, Here’s How

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Climate change threatens to make dry regions even drier, so scientists at UC Berkeley created a device to make water out of thin air.

At least one hundred million people live in desert regions around the world according to the UN, and they survive off of less than 25 cm of rainfall each year, and for many, even that minuscule water supply is under threat as the climate crisis is making dry areas even drier.
So scientists at UC Berkeley have been experimenting with materials that can pull drinking water out of thin air.

That’s right, right out of thin air.

A chemist at the University of California, Berkeley reported that he and his colleagues have created a solar-powered device that could provide water to millions living in water-stressed regions.

At the device’s heart is a porous crystalline material, known as a metal-organic framework (MOF), that acts like a sponge: It sucks water vapor out of air, even in the desert, and then releases it as liquid water.

A single gram of an MOF can have the surface area of a football field, and depending on the metal and organic molecules they’re made of, MOFs can be tailored to capture various different things in their pores. For example, an MOF could have the ability to capture CO2 and turn it into the fuel methanol, or neutralizing nerve agents like sarin gas. The function the Berkeley scientists used their MOF for was extracting water vapor that’s present in the air.

The lead researcher behind the device started a private company called Water Harvesting.

The company’s plan is to launch a microwave-sized device that can supply 2 adults with enough water for their daily hydration and cooking needs. Eventually the research team envisions a harvester device big enough to supply a small village. If the devices end up being affordable, safe, and reliable enough, these metal-organic frameworks have the potential to turn even the driest desert into an oasis.