Mitigation Measures of Flood and Drought for Ayeyarwady Basin

Abstract

This research represents about the mitigation measures of flood and drought for Ayeyarwady Basin. The objective of this study is to propose the mitigation effect of flood and drought in Ayeyarwady Basin. In this study, flood vulnerable areas for Ayeyarwady Basin are assessed by using Hydrologic Engineering Center’s River Analysis System (HEC-RAS) model, GIS and Remote Sensing technique. Landuse classification map (2014 year) is extracted from Google Earth Engine based on land satellite LANDSAT-7 data and then Curve Number (CN) grid map is developed. Landuse classification in year 2014, the closed forest is found as about 48.9% and deciduous forest is about 26.3% of Ayeyarwady Basin. After delineating the flood plain area in HEC-RAS, the flood map for Ayeyarwady basin is developed by using Arc-GIS. The flood area by using 2014 landuse classification is 10414.18 km2 and the flooded regions are part of Mandalay, Sagaing, Monywa, Pakokku, Magway, Yaynanchaung and Thayet. According to the landuse classification in 2000 year, closed forest is 62.8% and deciduous forest is 28.05%. The flooded area is about 7081.03 km2. According to these scenarios, it is found that flooded area can be reduced about 32% due to forestation. For the spatial characterization of drought, Spatial interpolation (Spline) method in Geographic Information System (GIS) is used to generate drought severity maps. According to the drought severity map and severity values, Aunglan, Magway and Nyaungoo are the most severity regions and which are considered as pilot regions in this study. Two scenarios of rainwater harvesting are proposed to mitigate the drought severity area. In the first scenario, rainwater is collected from the roof top and stored in the storage tank.The average maximum monthly collected rainwater  per house hold for three types of roofing area are 4.423 m3, 13.539 m3 and 27.214 m3 respectively. The second scenario is to recharge the rainwater volume directly over the different types of landuse area and soil group. As a result, the recharge volume for Aunglan, Magway and Nyaungoo regions are 530.85 Mm3/year, 219.312 Mm3/year and 224.863 Mm3/year respectively. Finally, these scenarios are proposed to mitigate the effect of flood and drought in Ayeyarwady Basin