Abstract. Flash floods result from the abundant precipitation occurring in the Meghna basin, leading to significant losses of agriculture (specially Boro rice, the only crop of the farmers) in the north-eastern region of Bangladesh. Present practice to save the crop is compartmentalization of depressed area by submersible embankment. After harvesting, water is allowed to enter for fish cultivation with having objective to maintain biodiversity of that area. However, the crop is frequently damaged due to early flash flood before harvesting. Allocating necessary storage to provide spaces for excess water can save the crop. The present study calculates the necessary storage with a new method: Flood duration curve (FDC) to ameliorate floods and estimates water storage capacity of 6 compartments (locally termed as “Haor”) by using satellite-based citizen science haor volume estimation technique. According to the capacity it is observed that early flash flood can be managed by sacrificing crops of one or two haors.