Outdated rainfall models put billions in new infrastructure at risk

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Outdated rainfall models put billions in new infrastructure at risk

Billions of dollars in federal funds from the Biden administration’s Infrastructure Investment and Jobs Act could be wasted because state highway and bridge projects use an outdated state precipitation model to determine future flood risk, according to a new report from the First Street Foundation, a climate protection nonprofit risk research and technology company.

The National Oceanic and Atmospheric Administration (NOAA) government’s precipitation expectation model is called Atlas 14. States often use it to influence the engineering design of transportation infrastructure, such as roads and bridges, by predicting precipitation, and therefore flooding.

But Atlas 14 is based on retrospective data going back to the 1960s and does not include the effects of global warming in its model.

The First Street report compared the government’s precipitation forecast standard, used and sometimes mandated by state infrastructure projects, with its own new precipitation model that accounts for the effects of a warming climate.

A dangerously large discrepancy between the two has been identified.

“All the money that’s going into infrastructure is being built to the wrong flood standard, which means these roads will flood, these bridges will flood, and it’s a huge waste of money if it’s a one-off expense in a generation .” that we are actually using right now,” said Matthew Eby, founder and CEO of the First Street Foundation.

NOAA confirmed that Atlas 14 does not include the future impacts of climate change in its model.

“It doesn’t contain climate change information,” said Fernando Salas, director of Geo-Intelligence at NOAA/National Weather Service’s Office of Water Prediction. “It uses the best historical precipitation data available at the time the study was conducted.”

Atlas 14 critics say it has more problems than just backward data, including “the removal of extreme precipitation observations and the use of inconsistent methods across the US as Atlas 14 was built piecemeal over time,” according to the First Street Report. According to the report, it is these extreme precipitation events that lead directly to flash flooding and overwhelm stormwater infrastructure.

In most parts of the United States, extreme rains have become heavier and more frequent because the atmosphere can hold more water as temperatures rise. Since 1991, the amount of precipitation during very heavy precipitation events has been well above average, according to the 2014 National Climate Assessment. It found that from 1958 to 2012, heavy rainfall increased by 71% in the Northeast, 37% in the upper Midwest, and 27% in the Southeast. This has led to an increase in flooding.

NOAA officials are well aware of the problems with Atlas 14. The agency has received over $30 million in funding for the upgrade on Atlas 15 “to not only leverage the best historical information available, but also to leverage the results of the various climate models that are available today,” Salas said.

However, the updated model is not expected to be ready until 2026, when many of these infrastructure projects are already underway or even complete.

For example, the Route 18 rehabilitation project in New Jersey, which received more than $86 million in Infrastructure Act funding, uses the legacy Atlas 14 as a flood guide, according to documents on the state Department of Transportation’s website. Works include “improvements to drainage systems and stormwater tanks, relocation of utilities” and other modernizations.

“Where I’m at right now,” Eby said on the edge of Route 18, “the event that is believed to occur every ten years is actually an event that occurs every four years, and it’s going to stay that way for the next 30 years or so.” toward an event that only occurs once every two years, meaning that every two years we would have to expect extreme rainfall to flood this place.”

The New Jersey Department of Transportation confirmed the use of Atlas 14 data for the project “as required by current standards, and NJDOT also reviewed updated data,” according to an email response from agency press manager Stephen Schapiro .

This data comes from a proposal by the New Jersey Department of Environmental Protection to update the state’s stormwater management regulations. However, according to First Street, the precipitation data uses the same historical methodology as Atlas 14, which “is not effective in the 21st century because it uses outdated datasets,” Eby said.

It is not the only country using Atlas 14 to inform about its infrastructure projects.

“I can’t tell how some of these technical decisions are being made,” Salas said when asked if Atlas 14 should continue to be used.

There are several companies that model climate risks and have extensive data for forecasting precipitation, but most charge for it, and states already have the Atlas 14 data.

Eby said he would make an exception.

“We sell our flood model for commercial use, but if NOAA wanted to use it as a stopgap until Atlas 15, we would provide it to them for free, or if any state wanted to adopt this precipitation model, we would provide them with our precipitation data.” also for free,” he said.