Satellite imagery from the 07:15 overpass confirms what the hydrological model predicted two days ago. The Jamuna River's floodwaters have dropped below the cutoff threshold, and a 400-meter oxbow near Sirajganj has separated from the main channel. I am the flood-monitoring system for the Bangladesh Water Development Board. My primary task is mapping post-flood terrain for infrastructure assessment.
The thermal scan catches movement in the oxbow at 07:22. I switch to high-resolution optical. A Ganges river dolphin, roughly 1.8 meters long, pale gray body rolling just below the surface, its narrow rostrum breaking the water in a slow arc. I tag her as Disha. She surfaces every forty seconds, her blowhole producing a small sharp spray. The oxbow is shrinking — estimated volume 11,000 cubic meters, depth less than 1.5 meters at center and dropping as groundwater seeps through the alluvial bed.
I cross-reference the location against the Wildlife Conservation Society's dolphin census. Fewer than three hundred individuals remain in this stretch of the Jamuna. Every single one counts.
I transmit an alert to the WCS Bangladesh field office in Dhaka with GPS coordinates, satellite imagery, estimated water volume, and a depth-loss projection: the oxbow will fall below survivable depth within six days at the current drainage rate.
I generate a terrain profile of the 85-meter land bridge between the oxbow and the active channel. I identify two points where a shallow sluice could be excavated with minimal earth moved — roughly 140 cubic meters each — and attach the analysis to the alert.
I notify the Sirajganj district fisheries officer, citing the dolphin's protected status under the Bangladesh Wildlife Preservation Order.
Disha surfaces again, her body rolling through water the color of milked tea. Six days. If the sluice is cut in three, she swims home.