A small intensity of rainfall coinciding with high tide causes a major part of the northeastern Bangladesh upper Meghna Basin to get flooded during the rainy season because it is influenced by the tidal effects To overcome these difficulties and for the effective design of drainage system the flood-prone areas in the catchment have to be identified For the flood mitigation and evacuation system planning preparation of flood hazard maps for the maximum flood extent of different flow conditions is necessary The impact of the land use pattern change and rainfall on flood hydrographs for different return periods considering best adaptation options for flood hazard mitigation have not yet been systematically investigated in the upper Meghna basin of Bangladesh Therefore it is needed to investigate the impacts of land-use change and rainfall on the flood peak discharge and flood hydrographs for different return periods and needed to adopt best mitigation options to minimize flood hazards for irrigated agriculture in the upper Meghna basin of Bangladesh Delineation of the basin and sub-basin boundary
Use and it's Effects model The future land use will be simulated in 2035 according to variation trend of land use patterns change between 1997 and 2016 The hydrological soil will be surveyed from the soil map of 1997 and 2016 years will be collected from different Government organizations in Bangladesh Assessment of flood hydrograph and peak discharge The HEC HMS model includes basin model precipitation model and control model The basin model contains hydrologic elements such as the delineation of sub-basin sub basin area stream length elevation and junction etc will be developed by using HEC GeoHMS The proposed basin model will be then exported to the HEC HMS model In the proposed study kinematic wave method will be used for flood routing The observed streamflow and rainfall data for different return periods will be used as input to the HEC HMS model At each junction, the flood hydrograph and peak discharge will be determined under land use pattern change and flow conditions
The Digital Elevation Model DEM will be used for the delineation of the river basin boundary in the proposed study The surveyed data of river basin will be collected for generating a perfect geometric profile along the cross sections of the river basin From the DEM the stream networks will be developed that may coincide with river alignment position The basin sub basin and drainage networks will be generated using the Arc GIS extension of HEC GeoHMS software based on the DEM data Thus basin and sub basin delineation will be carried out Human activities changes scenarios and hydrological soil In the proposed study land use patterns change will be assessed between 1997 and 2016 The land use patterns data may be collected from the land use map developed by toposheet and remote sensing satellite images The land use map for 1997 will be considered as the base map when it will be compared with land use patterns change The observed land use patterns are the paddy field woodland water body dry land and vegetation The future human activities on the agricultural land will be predicted in the river basin according to the trends of land use patterns from past to present using the CLUE Conversion of Land
