When Vietnamese look into the waters of the country’s Red River, they get a reflection of their own interests. The river is a vital source of hydroelectric power for Vietnam’s fast-growing economy. Farmers depend on its silt-laden waters to irrigate and fertilize the rice paddies that dominate its vast delta.
At the same time, the inhabitants of low-lying cities such as Hanoi fear the flooding brought by the annual monsoon rains. In 2018, flooding caused government officials to order the evacuation of more than 6,000 people from a Hanoi suburb.
“Managing these sometimes divergent perspectives requires tradeoffs,” said Julianne Quinn, an assistant professor and one of the newest additions to the faculty in UVA’s Department of Engineering Systems and Environment. She specializes in improving optimization and simulation methods used to design and manage water resources systems. As a graduate student and post-doctoral fellow, she was part of a team of researchers from Cornell University and Politecnico di Milano developing tools to help Vietnamese planners better weigh the objectives of Red River stakeholders.
To manage the Red River, the Vietnamese government constructed a network of reservoirs upstream from Hanoi. They are used to regulate the flow of water reaching Hanoi, store water for irrigation during the dry season and provide hydroelectric power. The challenge is that there is no single optimal water level for all three uses. While Quinn’s research team focused on Vietnam, governments — and engineers — grapple with similar balancing acts in communities all over the world, especially as land development and the effects of climate change stress infrastructure systems and resources.
Quinn pointed out that maintaining low reservoir levels favors flood protection, creating capacity to absorb high water and minimize flooding. On the other hand, high water favors hydropower production. The higher the water behind the dam, the more energy that is available to generate electricity at its base. High water also ensures that there is a reserve for agricultural uses in times of drought, although releasing water during the dry season diminishes hydropower production.
These high- and low-water strategies also have ecological consequences. Compensating for these consequences further complicates decision-making.
With funding from the Italian Foreign Ministry, the research team partnered with VietNam Electricity, the Ministry of Agriculture and Rural Development, the Central Committee for Flood and Storm Control and the Ministry of Industry and Trade. Together they built models of the Red River reservoir system, sediment transport and downstream flood routing. “Rather than try to come up with a single set of operating guidelines, we presented the stakeholders with a set of options that would enable them to meet their objectives in different ways,” Quinn said.
Traditionally, management strategies are derived from what is considered the single best model for representing the system objectives, but this method necessarily involves simplifications and assumptions. “Some commonly used quantitative representations of system objectives can lead to severe unintended consequences,” she said.
Rather than default to the “best” model, Quinn analyzes multiple alternative ways to frame the problem. In the process, she uncovers inherent biases and is able to create more nuanced, accurate recommendations.
In the Red River case, taking this approach revealed more appropriate ways for the Vietnamese Central Committee for Flood and Storm Control to quantify flood risk when designing and evaluating alternative operating policies for the system, she said.
The next challenge for Vietnam will be factoring climate change into water management strategies. The annual monsoons are the most critical factor in the volume of water flowing through the system. Most climate projections suggest that the overall amount of precipitation falling during the monsoons will increase, but that the intensity of the monsoons will become more variable from one year to the next, as will the weather extremes within a single year.
In addition, they must also take into account rapid development and population growth across the Red River Basin. Development increases the damages from flooding and degrades the ecosystem by altering the river system’s natural flow.
“This is a highly complex situation that is changing across a number of dimensions,” Quinn said. “This means that the tools we offer decision-makers must reflect this complexity.”
Quinn is currently exploring a range of potential projects, from developing computational approaches that better reflect how people use information in different circumstances to determining the role of water infrastructure in climate adaptation.
“This department has been an ideal platform for me,” she said. “What I do day to day is systems engineering but the applications and research questions I am interested in are in the environmental arena.”