UVA Engineers Use Global Satellite Imagery and Other Open-Source Information to Inform an International Water Conflict
From their perch in Earth’s orbit, a pair of Sentinel-1 satellites zip from pole to pole, constantly snapping pictures of our changing world — day or night, day after day, regardless of the weather — using their Synthetic Aperture Radar capable of penetrating clouds and darkness to make highly detailed images down to 15 feet.
A pair of sister satellites, Sentinel-2, are hot on their heels, capturing high-resolution, optical images to monitor global soil and water coverage, among other things.
These roving eyes in the sky are just a few of the satellites that make up the Copernicus joint initiative between the European Commission and the European Space Agency to provide real-time information on the environment and global security. The data they collect is continuously beamed back to Earth, where it is archived and made publicly available to scientists, researchers and developers using Copernicus Open Access Hub and Google Earth Engine.
In August 2020, Prakrut Kansara, a University of Virginia School of Engineering Ph.D. student in professor Venkataraman “Venkat” Lakshmi’s Department of Engineering Systems and Environment group that specializes in hydrology and satellite assimilation and validation, took the information from these satellites and Google Earth Engine, combined them with data from other sources and zeroed in on one of the globe’s growing hotspots, the Grand Ethiopian Renaissance Dam, or GERD, on the Blue Nile.
In the first published study of the GERD filling, Kansara found that by September 2020, Ethiopia’s government had intentionally filled the reservoir with more than 5% of its total volume of more than 67 billion cubic meters, despite assuring the global community that it hadn’t begun the filling process since there was no agreement yet between Ethiopia and downstream countries. Kansara’s research further suggested that the filling of the GERD reservoir could choke the flow of water downstream, especially during droughts, triggering a possible humanitarian crisis.
The results of Kansara’s findings were published in the March 2 issue of the open access journal Remote Sensing, an influential, peer-reviewed publication that focuses on the science and application of remote sensing technology.
Located less than 20 miles from the border with Sudan, the dam feeds a massive concrete, hydroelectric power plant. When complete sometime in 2023, the dam will be the largest in Africa at more than a mile long and 475 feet tall and the power plant will more than double Ethiopia’s current electrical generation, providing ample energy throughout the country — and possibly the region.
However, the dam has been a source of contention since the plan was first made public by the Ethiopian government in March 2011. Millions of Egyptians, and to a slightly lesser extent the Sudanese, are highly dependent on the Nile for their drinking water and agricultural irrigation. Mohamed Abdel-Aty, Egypt’s minister of water resources and irrigation, is among the co-authors of the Remote Sensing publication.
The Nile, the longest river in the world, is formed when the Blue Nile merges with the White Nile outside of the Sudanese capital of Khartoum. Seasonal precipitation in the Blue Nile basin, which originates in Lake Tana in the northwestern Ethiopian Highlands, makes up roughly 85% of the water flowing into the Nile. Egyptians see any manmade constriction of the flow into the Nile as a potential affront to their water and food security, despite having their own dams on the river.
For decades, Egyptians have banked on agreements made in the late 1920s and late 1950s to prevent any major construction on Nile River tributaries. A 1959 agreement essentially gave all the Nile waters to Egypt and Sudan, nothing to Ethiopia, and gave Egypt veto power over any construction projects on the tributaries.
All that changed in 2011 when Ethiopia decided to self-finance most of the construction of the $4.8 billion dam, saying that the dam will have no impact on the water flowing into the Nile and instead will pave the way for affordable electricity in the region with the potential to pull millions out of poverty.
Last August, Lakshmi was approached by Hesham El-Askary, a professor of Earth system science and remote sensing at Chapman University in California and professor on leave from Alexandria University in Egypt, to see if Lakshmi’s group at UVA Engineering would be interested in studying the dam, as it was suspected that Ethiopia had begun to fill the reservoir. He also asked Lakshmi if his team could use the data to predict what might happen downstream of the dam where fluctuations in flow during its filling over the next 5-15 years could have potentially tragic consequences, especially during droughts that are a common occurrence as the Nile moves through the Egyptian deserts.
“One of the things I insisted on from the beginning is that we don’t make political or policy statements,” said Lakshmi, who was appointed to the Water Science and Technology Board of the National Academies of Sciences, Engineering and Medicine last year. The board's objective is to improve the scientific and technological basis for resolving important questions and issues associated with the efficient management and use of water resources.
“Our work on this project focuses on the math and on the nuts and bolts of science underpinning policy or political decisions, but not making decisions,” he said.
Lakshmi is among multiple faculty members in the UVA Department of Engineering Systems and Environment studying water resources through a variety of cross-cutting approaches, from meeting basic needs at the point of use through filtration systems to monitoring infrastructure through sophisticated data analysis and risk assessment. He and his colleagues are also part of a broader community of researchers at UVA Engineering addressing environmental challenges.
With funding from NASA, Kansara began by taking data from a variety of open sources including the Sentinel satellites; NASA’s Shuttle Radar Topography Mission that provides global, high-resolution typographic data; the Gravity Recovery and Climate Experiment satellites that measure changes in total water; NASA’s Global Precipitation Measurement Mission that estimates amount and structure of rainfall; and the Global Land Data Assimilation system, which combines satellite and ground-based observational data to study land surface changes at a global scale. Using Python, an open-sourced programing language, Kansara assimilated all the data to accurately determine how much the dam had already filled in 2020.
Because of this approach using open-source data and software, any potential bias was eliminated as anyone could take the same verified and accessible data and come to the same conclusion.
“We want to be as rational as possible in our approach and not take sides,” Kansara said.
He grew up in an arid section of India and understands the implications of water security.
“The region where I lived is very water-scarce, where wells are very, very deep,” he said. “I’ve personally seen this with my own family and friends where they talk about how important water resources are and how important it is to conserve them.”
Recently, Sudan’s Prime Minister Abdalla Hamdok reached out to the United Nations, the African Union, the European Union and the United States to seek mediation on the filling of Ethiopia’s dam after talks with the African Union representatives chaired by South Africa failed in January to reach an agreement among the three nations. Ethiopia’s Minister of Water, Seleshi Bekele, also announced earlier this month that Ethiopia will commit to filling the dam this summer regardless of whether an agreement is reached.
“Dr. Lakshmi has a strong history working with many different people in the global community,” said Jared Entin, program manager for terrestrial hydrology in NASA’s Science Mission Directorate. Entin has worked closely with Lakshmi over the years on several global projects. “While he’s downplayed the necessary ingenuity, it’s not everyone who can understand the problem, determine what’s required, and then have the breadth of knowledge of different data sources and see the way in which to combine them to produce practical products for regional decision makers.”
“These dams are the batteries of a country’s economy,” Lakshmi said. “At the same time, what happens when there is low rainfall? The people downstream will have to convince the operators of the GERD reservoir to release more water. Imagine if they [Ethiopia] held up the release of water, the Blue Nile could have lower than normal flow downstream.”
“This monitoring will at least keep people abreast of what is happening,” Lakshmi said. “People in Ethiopia. People in Sudan. People in Egypt. Transboundary water disagreements are real. Maybe this monitoring can prevent a or at least predict one.”