MINT & BRIC |
Fighting flood disinformation
A research team from the University of Washington has used satellites to help stem the spread of disinformation during the August 2024 transboundary flooding in India and Bangladesh
DURING 20-21 AUGUST 2024, the Northeastern Indian state of Tripura, which is mountainous, received heavy rainfall leading to destructive flooding and loss of life. Downstream of this region is the low- lying country of Bangladesh formed by the deltaic deposits of the Ganges and Brahmaputra rivers. The lack of preparation for such a rapid onset of extreme flooding impacted more than a million people forcing 80,000 individuals into the 557 makeshift relief camps set up by the Tripura State Government (Reuters, Augus 24 2024).
As the flood travelled downstream crossing the
Above: Figure 1. Map of South Asia (left panel) displaying the mountainous Indian state of Tripura in the Northeast and low- lying Bangladesh (right panel)
international boundary with Bangladesh, the flood quickly became a transboundary flood, catching the inhabitants of Bangladesh also off guard due to lack of early warning. As news of Tripura having to open the gate of its sole
hydroelectric Dumboor dam became public, a flood of disinformation ensued within Bangladesh as the actual flooding wreaked havoc. Some of this disinformation presented itself as conspiracy theories or conjectures, such as: Did India intentionally flood Bangladesh by opening the gate of Dumboor dam?”, “Was it really such a heavy and widespread rainfall event that the dam played no role?” and “Could India (Tripura Government) not have warned downstream authorities in Bangladesh?”
Tackling disinformation with satellites
Above: Figure 2. Picture taken of the flooding as it passed through Agartala of Tripura on August 21, 2024) by relatives of the first author (Pritam Das)
Amid such wild speculation shared widely by the public, as the catastrophic flooding needed a rapid disaster response and relief in low-lying Bangladesh, we asked ourselves, on 22 August 2024, “what do satellites in space tell us about this evolving transboundary flooding given that satellites can see both sides of the border without bias?” (Hossain and Katiyar, 2006).
We explored the use of satellites to understand the evolving transboundary flooding situation on the ground, the potential role of upstream dam and the skill of weather forecast. The goal of this exploration was to eventually develop a tool that can improve livelihoods through sustainable application of earth science, remote sensing and advanced information technology. This goal happens to be a core research philosophy of the group we are affiliated with at the University of Washington, known as SASWE (https://
www.saswe.net). In other words, given the plethora of big data and advanced information technology with improved modeling, we asked: “what can Earth observations and data science do to make a positive impact for everyone on both sides of the border?” This question takes particular importance for two
reasons. The first reason is personal wherein the flood impacted the hometown of the first author (Pritam Das) who is from Agartala, Tripura. The second reason is the Surface Water and Ocean Topography (SWOT) satellite mission that was launched in December 2022 started streaming data for the public on water on the surface. SWOT makes the Tripura-Bangladesh situation
particularly unique and exciting as it can measure, for the first time in satellite remote sensing history, water elevation and inundation extent to provide a more powerful and all-weather synopsis of the evolving flood situation and reservoir state.
What did Earth Observation data
from satellites and modelling reveal? Figure 3 shows if the widely available precipitation forecasts from global weather prediction models, such as the Global Ensemble Forecasting System (GEFS) produced by NOAA, revealed anything insightful. It also shows where most of the precipitation fell based on observation from the Global Precipitation Measurement (GPM) mission data product called IMERG. We are able to make the following observations to dispel the flood of disinformation: Most of the precipitation and runoff occurred downstream and outside of Dumboor dam catchment. This can be inferred by comparing the left panel’s lower right image with the location of
Figure 3. Left panel – satellite observation of precipitation from August 18-21, 2024; Right panel, forecast of precipitation made on August 18, 2024, three days ahead of the date when most intense precipitation took place on August 21, 2024. The location of the Dumboor hydroelectric dam is shown in the inset in each panel
14 | March 2025 |
www.waterpowermagazine.com
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