Lessons for Iowans in the wake of Harvey


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A map from the National Hurricane Center illustrates predicted landfall for Hurricane Irma, a category 5 storm, over the weekend. (National Hurricane Center)
Jenna Ladd| September 7, 2017

As some of the floodwater finally recedes from the Houston area following Hurricane Harvey,  Hurricane Irma, a category five storm, threatens to devastate the Florida Keys this weekend.

Climate change increased the amount of rainfall that fell on Houston during the recent storm, according to a statement from Clare Nullis Kapp, media officer for the World Meteorological Organization. Karen Tigges, a Des Moines resident and operations analyst at Wells Fargo, said in a recent Des Moines Register Letter to the Editor that Harvey has something to teach the people of Iowa. The letter reads:

“Houston: A tragic example of a city caught at the mercy of worsening storms and increased rainfall. Flooding is nothing new to Houston, but it appears that this time they are really paying the price for unwise growth.

Unfortunately, flooding is not unfamiliar to the city of Des Moines either. We are growing in the metro as well. We must take the warnings of storm events seriously. It’s said that the lack of zoning ordinances in Houston led to the loss of wetlands and grasslands that could have absorbed at least some of the onslaught of water. How does that compare with planning for growth here in the metro area? Is the growth of our urban areas leading to higher risks of flooding due to more impermeable surfaces in the form of more paved roads and rooftops?

As the city prepares for a future that will likely include more intense rainfall events, thanks to a warmer, more humid climate, we citizens need to take an active role in seeing that effective planning and policies are put in place to make Des Moines ready to face this unpleasant reality.

We can do that by weighing in on the city’s new planning and zoning code. We also need to do that by electing and supporting leaders that will be proactive in setting the course of the metro area on a path of resilience and preparedness for what storms of the future may bring.”

— Karen Tigges, Des Moines

Houston flood expected to drain slowly


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Give its flat landscape and dearth of flood control infrastructure, the city of Houston will rely primarily on slow-moving bayous to drain the area. (Adam Baker/flickr)
Jenna Ladd| September 1, 2017

While the downpour in Houston has finally subsided, the Texas city has few options for draining the 15 trillion gallons of water that fell in the region.

The city of Houston has no levees or pumps or flood walls it can call on to drain water more quickly back into surrounding bayous. As a low-lying coastal plain, it also has a rather flat landscape. Arturo Leon, a professor of water resources engineering at the University of Houston said, “This means the capacity for drainage is very slow. If there were a slope, then it would drain faster,” in a report by Scientific American.

In the last thirty years, the city has grown a great deal, all without any zoning laws that regulate development, even in flood prone areas. For example, since 2010 about 7,000 residential buildings have been built on land the federal government considers a 100 year floodplain, according to a review by the Washington Post. Stormwater drainage systems have not kept pace with the area’s development.

Sam Brody, director of the Center for Texas Beaches and Shores at Texas A&M University, said, “Houston is the Wild West of development, so any mention of regulation creates a hostile reaction from people who see that as an infringement on property rights and a deterrent to economic growth. The stormwater system has never been designed for anything much stronger than a heavy afternoon thunderstorm.”

As a result, the city relies heavily on surround bayous to reabsorb rainwater. Bayous are slow moving, and especially so on Houston’s flat landscape.

A list of options for donating to victims and displaced residents in the area can be found here.

Climate change to make storms like Harvey more frequent, intense


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A Texas National Guard member rescues a Houston resident during Hurricane Harvey. (The National Guard/flickr)
Jenna Ladd| August 30, 2017

More than fourteen million olympic-sized swimming pools could be filled with the amount of rain that has fallen in Houston as a result of Hurricane Harvey, and scientists say that climate change added to the deluge.

To begin, sea surface temperatures near where Harvey picked up its strength were about 1 degree Celsius higher than average. The Clausius-Clapeyron equation, a law of thermodynamics, says that the warmer a body of air is, the more moisture it can hold. In this case, the atmosphere surrounding Hurricane Harvey was able to hold roughly three to five percent more moisture than usual.

“The water in the Gulf of Mexico is the heat reservoir to support these hurricanes,” said Ben Kirtman, an atmospheric scientist at the University of Miami, in a report from NPR. Kirtman added, “For a small change in temperature, you get a huge amount of evaporation.”

In the last three decades, sea levels have risen worldwide by about six inches thanks to a warming climate and, in part, to human activities like offshore oil drilling. Higher sea levels make inland floods more devastating.

Climate Central scientist Ben Strauss said, “Every storm surge today reaches higher because it starts from a higher level, because sea level is higher. A small amount of sea-level rise can lead to an unexpectedly large increase in damages to most kinds of structures.”

Scientists are careful to point out that climate change did not directly cause Harvey, but is likely to produce storms like it more often. A recent report from the National Academy of Sciences, Engineering and Medicine revealed that category 4 hurricanes like Harvey will occur more frequently in the future due to a warming climate.

So far, fourteen casualties have been identified as the storm continues to devastate the area.

New study assesses flood risks for schools nationwide


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The impact of flooding on schools is often compounded by aging infrastructure, according to a recent study. (FEMA)
Jenna Ladd| August 8, 2017

A recent study by the Pew Charitable Trusts generated flood risk scores for 84,123 primary and secondary schools nationwide.

The report’s authors pointed out that flooding is the most costly and common natural disaster, affecting every region of the U.S. Many times, severe floods badly damage schools, causing them to close. For example, the study points out, floods in West Virginia in June 2016 cost $130 million in damage to regional schools.

Researchers used three metrics to generate county-wide composite flood risk vulnerability scores for schools in all fifty states including: a school’s location within a designated flood zone, the percentage of a school’s neighborhood (as represented by ZIP code) located within a flood zone, and the number of historical flood-related federal disaster declarations in that county.

Among the study’s major findings are that flood risk is distributed across diverse regions of the country. Schools with the highest flood risk scores were located in the Atlantic Coast, Gulf Coast, Mississippi River corridor, and southwestern Arizona. Similarly, those schools with the highest composite flood risk scores were located in both coastal and inland regions. Those 100 counties with the highest composite flood risk scores include 6,444 schools that serve almost 4 million students.

The study made some recommendations for steps policymakers can take to increase flood resiliency for schools. They included generating up-to-date local flood maps, developing pre-disaster flood plans for schools, working to leverage federal assistance, and relocating schools out of floodplains if possible.

The Pew Charitable Trusts full analysis can be found here.

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The highest flood risk areas are scattered across many regions of the country. (Pew Charitable Trusts)

EnvIowa Podcast: Dr. Larry Weber on flood mitigation and water quality improvement projects


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Jenna Ladd | June 29, 2017

In episode 7 of EnvIowa, we sit down with Dr. Larry Weber to learn more about the Iowa Watershed Approach. Dr. Weber is a UI professor of Civil and Environmental Engineering and Director of IIHR–Hydroscience and Engineering, which is the parent organization of the Iowa Flood Center.

Dr. Weber explains how the $96.9 million project came to be and how it improves quality of life for Iowans while protecting our natural resources and health. He tells of successes the Iowa Flood Center has had with its flood reduction and water quality improvement programs and discusses the organization’s fight to maintain state-funding earlier this year.

The director and his team work many long days and spend hours each week driving around the state to each of the nine watersheds included in the Iowa Watershed Approach. For Dr. Weber, his work’s motivation is clear. He said,

“As an Iowan, I grew up here, I’ve worked and spent my whole career here, and I plan to retire here. I want a livable state in which we can enjoy our water and natural resources, enjoy being in the outdoors, enjoy interacting with the rivers, lakes and streams of Iowa, and, you know, programs like the Iowa Watershed Approach, I think, are vital to the long-term sustainability of our resources in Iowa.”

The EnvIowa podcast is also available on iTunes and Soundcloud, a complete archive of EnvIowa episodes can be found here.

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Nine watersheds are a part of the Iowa Watershed Approach’s effort to reduce flooding, improve water quality and protect natural resources. (Iowa Watershed Approach)

Extreme weather takes the lives of 14 people


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Tornados ripped through eastern Texas on Saturday night. (Red Cross/flickr)
Jenna Ladd | May 2, 2017

Flooding and tornados swept across the Midwest and southern U.S. this weekend, leaving at least 14 people dead.

The National Weather Service reported that four tornados moved through eastern Texas beginning Saturday evening. The twisters left an area of destruction 35 miles long and 15 miles wide in Van Zandt County, according to Canton, Texas Mayor Lou Ann Everett. Primarily small towns were affected in the mostly rural area east of Dallas; four individuals lost their lives.

Strong winds and flooding in Arkansas took the lives of five residents near Madison county. Four additional deaths were reported in Missouri and Mississippi, also due to flash flooding and strong winds.

Tragically, severe weather events like these are becoming more common as climate change rears its ugly head. According to archived data from the U.S. Environmental Protection Agency’s webpage prior to President Trump’s inauguration, “In recent years, a larger percentage of precipitation has come in the form of intense single-day events.” Similarly, the amount of precipitation falling on the heaviest rain days has increased in the last few decades. Many regions of the U.S. are seeing significantly more severe river flooding, while other areas are ravaged by drought. The Midwest, Great Plains, and Northeast have seen a significant increase in flooding, but the Southwest has experienced a decrease.

Scientists are still evaluating the relationship between climate change and twisters. The EPA notes that climate change does lead to stronger and more frequent thunderstorms, which can cause tornados, but there is a lack of empirical data on the matter.

Researchers can confidently conclude that climate change has caused more intense and frequent heat waves, fewer frequent and less intense cold waves, and regional changes in floods, droughts, and wildfires.

2016 to be hottest year on record


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2016 will likely be the third consecutive year that shatters global temperature records, according to the World Meteorological Organization. (Fosco Lucarelli/flickr)
Jenna Ladd | November 15, 2016

The World Meteorological Organization (WHO) released a report yesterday which predicts 2016 to be hottest year on record.

The report, which was published at the global climate summit in Morocco, found the current global temperature to be 34 degrees Fahrenheit above pre-industrial levels. Earth’s global temperature has reached a new peak for the last two years, and 2016 could make three. Experts say that the El Niño weather phenomenon is partly responsible for higher temperatures during the first part of the year, but human activity can be blamed for the rest. Petteri Taalas is the WMO secretary general. He said, “Because of climate change, the occurrence and impact of extreme events has risen. Once in a generation heatwaves and flooding are becoming more regular.”

Extreme heat waves have been reported around the world throughout the year. Temperatures soared to 109 degrees Fahrenheit in South Africa in January, 112 degrees Fahrenheit in Thailand in April and 129 degrees Fahrenheit in Kuwait during July. WMO stated that at least half of the extreme weather events of recent years have been human-induced, they noted that the risk of extreme heat has increased by ten fold in some places. The United Nations Food and Agriculture Organization has found extreme weather and climate-related events effect the farming and food security of over 60 million people worldwide.

Climate scientist Michael Mann of Penn State University responded to the report. He said,

“It is almost as if mother nature is making a statement. Just as one of the planet’s two largest emitters of carbon has elected a climate change denier [Donald Trump] – who has threatened to pull out of the Paris accord – to the highest office, she reminds us that she has the final word.”

Mann added, “Climate change is not like other issues that can be postponed from one year to the next. The US and world are already behind; speed is of the essence, because climate change and its impacts are coming sooner and with greater ferocity than anticipated.”

Not all of the report’s findings were negative. Carbon emissions have largely stabilized over the last three years after decades of growth, which experts say is mostly due to China burning less coal. Also, even though 2017 promises to be an extremely hot year, it most likely will not break records.