Assessment of the flood vulnerability of shrimp farms using a multicriteria evaluation and GIS: a case study in the Bangpakong Sub-Basin, Thailand

Abstract

Flood disasters associated with tropical storms have caused extensive and repeated damage to shrimp farms located in the Bangpakong River Basin, Chachoengsao Province, Thailand, which features the largest area of inland shrimp farming in the country. This study aims to assess the current vulnerability of shrimp farms to flooding and to examine the shrimp farmers’ actual adaptation practices for coping with floods based on past flood events. A flood vulnerability map was developed based on the geo-environmental characteristics of the study area. The map was produced through the use of geographic information system methods and a multicriteria evaluation. The current vulnerability map indicates that the majority of shrimp farms in the Bangpakong River Basin are highly vulnerable to flooding when the 10-day cumulative rainfall is >250–300 mm. The highly vulnerable area identified by the map is consistent with the area impacted by flooding in 2011. Based on a questionnaire, the majority of shrimp farmers have developed various adaptation practices to cope with flooding. The most common practice for minimizing flood damage is to increase the height of dikes around shrimp ponds. Because of budgetary constraints, approximately 20 % of small-scale shrimp farmers did not implement any adaptation practices and risked potential damage. With increasing climate change threats, these research results are useful for planning and creating policies that can reduce flood damage to shrimp farms in vulnerable zones. The results can also be applied to other areas facing similar conditions.