rainwater

Cities and rainwater

September 24, 2024 By EarthWise Leave a Comment

Cities across the country are grappling with the problem that bigger, more frequent rainstorms occurring as a result of climate change are overtaxing the systems put in place to handle stormwater. Cities use a combination of so-called green infrastructure – such as rain gardens and porous pavements – and traditional gray infrastructure, such as pipes, tunnels, and pump stations.

In 2011, Philadelphia drew national attention for its Green City, Clean Waters program that was designed to manage the increasing amount of storm water using mostly green infrastructure. Thirteen years later, the city is experiencing billions of gallons of polluted stormwater overflowing its sewage outfall pipes each year. Green infrastructure is cheaper and faster to build, but it is not coping with increasing rainfall.

About 700 U.S. municipalities, mostly in the Northeast and around the Great Lakes, rely on these combined sewer systems. Based on updated climate projections, many are having to greatly increase gray infrastructure projects that include concrete holding tanks, tunnels, and pipes that can divert and hold onto flows until the rain stops, and water treatment plants can recover. These projects can take decades to implement and cost billions of dollars.

All across the country, cities are going to need to bite the bullet and make large-scale investments in conventional sewage infrastructure and repairs to stop billions of gallons of raw sewage from running into rivers. The increased storms present a daunting challenge for America’s cities.

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Faced With Heavier Rains, Cities Scramble to Control Polluted Runoff

Photo, posted August 29, 2011, courtesy of Reggie via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Mercury in tuna

March 25, 2024 By EarthWise Leave a Comment

Mercury is found throughout the ocean, and there is at least some of it in any fish one might eat. It is an element found naturally in the environment, but it is also a byproduct of manmade pollution. Generally speaking, bigger fish tend to have higher mercury levels than smaller ones, because they are higher up in the food chain. The more small fish those big fish eat, the more mercury builds up in their bodies. Tuna aren’t the biggest fish in the ocean, but they are very common in many people’s diets.

Increased mercury levels are a result of human activities like burning coal and mining which release methylmercury into the air. It then finds its way into the oceans in rainwater. Methylmercury is a particularly toxic chemical that affects the nervous system. Environmental protection policies in recent decades have helped to reduce mercury pollution.

However, a recent study by French researchers looked at the mercury levels in tuna over the past 50 years. They found that the levels have basically not changed since 1971. As a result, they are calling for more restrictive environmental policies to further lower mercury pollution levels.

The researchers explained that the lowering of mercury airborne levels to date has not necessarily been ineffective. They theorized that the static levels in tuna may be caused by the upward mixing of “legacy” mercury from deeper ocean water into the shallower depths where tropical tuna swim and feed. It could very well take decades to dramatically reduce ocean mercury levels.

Meanwhile, mercury content in tuna varies considerably by tuna type and source and there are both better and worse choices out there. Consumers should learn the facts.

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Mercury levels in tuna remain nearly unchanged since 1971, study says

Photo, posted November 7, 2015, courtesy of Mussi Katz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Alaskan Icemageddon | Earth Wise

January 25, 2022 By EarthWise 1 Comment

December saw some wild weather in Alaska. A combination of record high temperatures and torrential rainstorms resulted in the coining of the term “Icemageddon” to describe what was going on with the weather.

Kodiak Island in southern Alaska saw a high temperature of 67 degrees on December 26, which was warmer than it was in Southern California that same day. This set an all-time record for the warmest December day in Alaska. Such a high temperature is amazing considering how little sunlight Alaska gets at this time of year. And with warmer air comes wetter air, as the atmosphere is capable of holding more water vapor as temperatures increase.

As a result, that same day saw the interior of the state get an inch of rain in just a few hours, something that hadn’t happened for decades. But then, when temperatures plummeted again, all that rainwater froze.

Huge sheets of ice blocked roads and choked traffic in Fairbanks, Alaska’s second largest city. Indeed, it was the state’s transportation department that came up with the term icemageddon to describe the situation.

The extreme warmth in December is related to the same weather pattern that brought cold, wintry weather to the Pacific Northwest and Northern California. Those weather conditions resulted in hundreds of cancelled flights in Seattle, where temperatures dropped into the 20s, and in massive amounts of snowfall in the Sierra Nevada mountains in California. A strong area of high pressure anchored in the Northern Pacific resulted in a clockwise flow around it drawing warmer, more tropical air from the Pacific up to Alaska.

Climate change continues to push the envelope on what sort of weather is possible all over the world.

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Alaska faces ‘Icemageddon’ as temperatures swing wildly

Photo, posted April 30, 2015, courtesy of Naql via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Land Use Change And Flooding | Earth Wise

September 30, 2020 By EarthWise Leave a Comment

Land use change refers to the conversion of a piece of land’s use by humans from one purpose to another. Land use change is commonly associated with biodiversity loss and increased greenhouse gas emissions. But how does land use change impact water cycles?

According to researchers from the University of Göttingen in Germany, IPB University, and BMKG (both in Indonesia), the expansion of monocultures, such as rubber and oil palm plantations, leads to more frequent and more severe flooding. The researchers explain the increase in flooding “with a complex interplay of ecohydrological and social processes, including soil degradation in monocultures, the expansion of oil palm plantations into wetlands, and the construction of flood protection dams.”

For the study, which was recently published in the journal Ecology & Society, the research team interviewed nearly 100 Indonesian farmers, villagers, and decision-makers in Sumatra. The team supplemented its research with data on precipitation, river and groundwater levels, soil properties, and regional mapping.

During large-scale land use change – like plantation expansions – newly-compacted soil causes rainwater to runoff as opposed to being absorbed. As more plantations are established in floodplains, the owners try to control flooding on their land by building barriers. But these dams often lead to increased flooding on neighboring lands. This understandably triggers social tensions between other farmers and plantation owners.

In order to reduce the negative impact of land use change on the water cycle, the research team suggests soil protection and improved planning – especially in floodplains – would be a good place to start.

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Land use change leads to increased flooding in Indonesia

Photo, posted October 8, 2018, courtesy of Artem Beliaikin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Saved By The Trees

February 1, 2019 By EarthWise Leave a Comment

The island of Kokota, part of the Zanzibar Archipelago off the coast of Tanzania, is tiny – only one square kilometer and home to just 500 people. For centuries, its residents subsisted by harvesting the islet’s natural resources, including its trees.

By the early 21st century, the deforestation had become unsustainable and the islanders faced a crisis. Fisheries were depleted, and rivers ran dry. The changing climate brought rising sea levels, more erratic rainfall, and coral bleaching in the surrounding waters. The situation looked hopeless.

But in recent years, the island has come back from the brink of ruin. Reforestation efforts began in 2008 on the larger island of Pemba and on Kokota itself, led by a Pemba local and a Canadian tree planter who formed the non-profit Community Forests International. Since then, nearly 2 million trees have been planted on the two islands. Enthusiastic volunteers on Kokota usually help plant trees during the rainy season, when water is plentiful.

Community Forests International, along with spearheading the tree planting effort, also built Kokota’s first school, and installed rainwater storage tanks for the community.

The conservation group is now devising ways for Kokota to make more money by diversifying its agriculture with crops that grow well in its climate including spices like cloves, cinnamon, and nutmeg. They are also helping locals to grow more and different vegetables in their gardens.

Small, poor communities are often the most vulnerable to the effects of climate change, such as drought, powerful storms, and depleted fisheries. Tiny Kokota provides an example of an environmental comeback. Fighting climate change requires economic solutions along with environmental solutions. For this one tiny island, it appears to have been saved by the trees.

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