Engineers help with water under the bridge and other tough environmental decisions

November 12, 2019

In two new papers, civil engineers explore how to make decisions using quantifiable social, economic and environmental guidelines.

It's called a sustainability-based optimized algorithm. It's designed to help land managers, city planners, engineers and policymakers make decisions about civil engineering projects. New bridge? Old bridge that needs new repairs? How about the school roof or the waterfront development? Every project has economic, environmental and social factors to consider.

"It's data-driven decision making -- it helps us put a number on different aspects of a project so we can collectively make more informed decisions," said Brian Barkdoll, professor of civil and environmental engineering at Michigan Technological University. "We can argue about how to put a number to it but there are ways, and once there's a number, it can be compared. It's about transparency in decisions."

Barkdoll worked with Hossein Tavakoli, PhD candidate in civil and environmental engineering at Michigan Tech, to lay out a sustainability-based optimization algorithm. The algorithm and an algae-based biofuels case study are the focus of their paper published in the International Journal of Environmental Science and Technology.

"It comes down to that we need to care," Barkdoll said, adding that in a second paper -- published in River Research and Applications -- his team dived deep into a particular example where decision making is tough: sea level rise. "We know coastal cities are in danger of flooding, and it is also surprising how it affects rivers and bridges upstream."

From energy to water to food, civil engineering projects greatly impact natural resources. Barkdoll hopes that engineers can step up to the challenge to help make decisions clearer, if not easier: "Engineers and researchers get information and make suggestions. We don't make the decisions but if we can present ideas that help decisionmakers make better decisions, then we should do that."

Algorithmic Sustainability

To Barkdoll, the hardest part is not the numbers, although he says there is plenty of nuance and room for improvement. Instead, the challenge is a fundamental shift in the way that engineers consider projects.

Typically, safety and cost are the highest priorities for civil engineering projects. What Barkdoll weaves into the sustainability-based optimization algorithm is considering the costs of a project over a lifetime.

"As engineers, we provide a number of options and we can still provide what people think they want -- the cheapest and safest option -- and present alternatives that look at not only the initial cost but a project's cost over its lifetime and the costs that are externalized," Barkdoll said.

A common example he points to is parking lots: It seems easy to cover a space and leave it be, but after accounting for maintenance costs, runoff and flood risk, carbon emissions, then the standard gutters and asphalt look less appealing by the numbers compared to putting in a rain garden, infiltration trenches and bioretention ponds.

The idea is compelling and as an engineer Barkdoll wanted to ensure the algorithm actually worked. So he and Tavakoli looked closely at biofuels made from algae.

Case Study: Algae Biofuels

In using a sustainability-based optimization algorithm, the key is to look at the whole life cycle of a project or process in terms of technical, environmental and social factors.

"The results of this algorithm show how considering all aspects of sustainability together may not necessarily be the same as a decision made based on any of those three criteria individually," Tavakoli said. "For example, if the study is in a region with water scarcity, the consumption rate of water might be considered to be the most important factor. Or, if the study is in a region with high air pollution, the emissions of air pollutants could be considered more important."

In the case of algal biofuels, the best answer varies based on location, source of the algae, economics and many other weighted factors. Coming to a decision using the algorithm is the civil engineering equivalent of personalized medicine -- just as a person's genetics, habits and medications make a difference, so do the nuances of an energy project.

Case Study: Bridges and Sea Level Rise

Scaling up from a single project, sustainability-based optimization algorithms can help decision makers break down the complexity of wicked problems like climate change.

In their River Research and Applications article, Barkdoll's team focus in on the technical side of sea level rise. Besides coastal impacts, rivers and streams would also flux with rising seas. Notably, as the team found, this affects how much sediment rivers carry, which affects fishing, flood control, bank erosion and bridge scour. Oceans rise, rivers fill up, and the downhill rush decreases -- so less sediment can move downstream.

While this could be helpful in some cases, such as dealing with less sediment building up against dams, the changes could also make some processes unpredictable. Bridge scour is an important one and fuller rivers from rising seas could scrape away the bases of already weakened infrastructure.

"This is where decision making matters," Barkdoll said. "These two papers can help use a broader decision-making process to make decisions about watersheds, rivers, what we build on them and what we don't, whether or not we need higher levees."

It's a process that can be applied even more broadly. Barkdoll's future studies look at analyzing other civil engineering and environmental challenges like water treatment, water distribution and water storage using sustainability-based optimization algorithms. At the end of the day, the data is big, the impact is big, the decisions are monumental -- and Barkdoll wants engineers to help.
-end-


Michigan Technological University

Related Sea Level Rise Articles from Brightsurf:

Sea-level rise will have complex consequences
Rising sea levels will affect coasts and human societies in complex and unpredictable ways, according to a new study that examined 12,000 years in which a large island became a cluster of smaller ones.

UM researcher proposes sea-level rise global observing system
University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science researcher Shane Elipot proposes a new approach to monitoring global sea-level rise.

Sea-level rise projections can improve with state-of-the-art model
Projections of potentially dramatic sea-level rise from ice-sheet melting in Antarctica have been wide-ranging, but a Rutgers-led team has created a model that enables improved projections and could help better address climate change threats.

How much will polar ice sheets add to sea level rise?
Over 99% of terrestrial ice is bound up in the ice sheets covering Antarctic and Greenland.

Sea-level rise could make rivers more likely to jump course
A new study shows that sea level rise will cause rivers to change course more frequently.

Sea level could rise by more than 1 meter by 2100 if emission targets are not met
An international study led by Nanyang Technological University, Singapore (NTU Singapore) scientists found that the global mean sea-level rise could exceed 1 meter by 2100 and 5 meters by 2300 if global targets on emissions are not achieved.

UCF study: Sea level rise impacts to Canaveral sea turtle nests will be substantial
The study examined loggerhead and green sea turtle nests to predict beach habitat loss at four national seashores by the year 2100.

Wetlands will keep up with sea level rise to offset climate change
Sediment accrual rates in coastal wetlands will outpace sea level rise, enabling wetlands to increase their capacity to sequester carbon, a study from the Marine Biological Laboratory, Woods Hole, shows.

Scientists discover evidence for past high-level sea rise
An international team of scientists, studying evidence preserved in speleothems in a coastal cave, illustrate that more than three million years ago -- a time in which the Earth was two to three degrees Celsius warmer than the pre-industrial era -- sea level was as much as 16 meters higher than the present day.

Corals in Singapore likely to survive sea-level rise: NUS study
Marine scientists from the National University of Singapore found that coral species in Singapore's sedimented and turbid waters are unlikely to be impacted by accelerating sea-level rise

Read More: Sea Level Rise News and Sea Level Rise Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.