Valuing the Economic Impact of River Floods and Early Flood Warning for Households in Bangladesh

Flood early warning systems have the potential to mitigate damages for vulnerable populations that experience river flooding in Bangladesh. We conducted a 2,247 household survey and series of focus groups to estimate the economic damages from 2016 river floods and the hypothetical savings of a 3- and 8-day warning for households living in the Jamuna River floodplain. Households were identified using geo-sampling, a novel geographic information system (GIS)–based sampling methodology that facilitates probability-based sampling where data are insufficient. Total damages for the entire flood plain in 2016 totaled to $1.3 billion, or 25% of household income and assets. Respondents estimated avoided damages from a hypothetical 3- and 8-day warning to be $73m and $85m, respectively, reflecting diminishing returns to additional days of early warning. With the hypothetical early warning, respondents derived the greatest savings from protecting their land, household/dwelling, and livestock. The greatest savings to households receiving a hypothetical additional 5 days of warning (from a 3- to an 8-day warning) would be realized in protecting agricultural production. Selling assets/livestock and employing protective sandbags were the preventative actions with the highest benefit–cost ratios that households said they would undertake. Importantly, only 11% of households received any early warning at all during the 2016 flood season, suggesting that the greatest benefits moving forward would be achieved by communicating existing or improved warnings more effectively to households in the floodplain.