Assessment of biophysical factors for storm surge hazard and their implications for food security

Abstract

Due to the physical factors associated with cyclonic storm surges, including area, depth and duration of inundation, some impacts are immediate in nature and some are prolonged. Impacts also very across different vulnerable livelihood groups. The study was conducted to assess the physical factors of cyclonic storm surge Aila, the immediate physical impacts, prolonged inundation impacts and the resulting implications for food security of different livelihood groups in polder 32 of Dacope upazila. The study demonstrates the efficient use of Participatory Geographic Information System (PGIS) method along with a range of PRA tools to collect and integrate the community knowledge and the capability to develop reliable and realistic storm surge inundation maps of different time periods since the occurrence of Aila. While the storm surge caused a number of immediate physical damages, which made thousands of people homeless, the prolonged impacts due to continued tidal inundation for several years meant that people could not recover quickly, mostly falling into food insecurity. While the polder was overtopped at many locations, it was the 5 major breaches that were the major contributors to surge inundation as well as repeated tidal inundation for several years. Repeated inundation was enhanced by slow and difficult infrastructure rehabilitation process, scouring of major breaching locations, widening of breaches, siltation of drainage channels, and man-made depressions. It took two years for Kamarkhola union and three years for Sutarkhali union to get fully free from inundation. Farmers, traditional fishermen, shrimp cultivators, wage laborers and Sundarban dependent people constitute the major livelihood groups who were affected by immediate storm surge inundation and prolonged tidal inundation. Consecutive loss of three to four cropping years happened due to water logging followed by adverse condition of land and soil quality (it took substantial time for the salts in soils to get flushed out), which were prominent as long term effects to farmers. Farmers in Kamarkhola union missed three complete cropping seasons (equivalent to 7,20,000 mounds of rice production), while the impact on farmers in Sutarkhali union was more severe as they lost four cropping seasons. While monsoon (Aman) cropping was possible after water receded, yield was reduced in the first year in Kamarkhola due to increased soil salinity from 20 to 22 mound/bigha before Aila to 15 to 16 mound/bigha after Aila. The loss of shrimp production in Sutarkhali union was 60,79,590 kg/year causing loss of income and livelihoods. Also, reduced production from 2,350 kg/ha to 470 kg/ha was a major source of income loss to shrimp cultivators. As Aila damaged all the belongings, the Sundarban dependent people suffered a significant loss of livelihood activities. About 30 to 60% reduction in income resulted for marginal to large farmers, while income reduced by 20% for small scale fishermen and 50% for the Sundarban dependent people. Large farmers were found to spend almost 70% of their income as food expenditure after Aila while it was 80 to 90% for medium and marginal farmers and small and medium farmers. Large, medium and small farmers were consuming almost 100%, 60% and 40% food (staple food rice) from own household production. But they were considered to be food insecure for spending more than 70% of their income as food expenditure after Aila. Wage laborers and Sundarban dependent people, who were food insecure prior to Aila were the most vulnerable to food insecurity in terms of all four dimensions, viz. availability, access, stability and utilization.