Proceedings of NCWRE 2018

Abstract

ABSTRACT Hydrologic models have emerged as a basic tool for studying real processes in a watershed hydrologic system responding to various climatic forcing. Bangladesh has been formed as the greatest deltaic plain at the confluence of the Ganges, Brahmaputra and Meghna and is highly vulnerable to climate changes. For this reason, study on hydrologic model is very important for Bangladesh. To set up a hydrological model and to determine discharge of the outlet of Dharla river basin using Satellite Estimated precipitation data are the main objectives of this study. In this study, hydrologic model of Dharla river basin with drainage area of 6120 sq.km is developed using HEC-HMS. Flash flood, Monsoon flood and bank erosion are some common issues with this river basin. A lumped hydrological model is developed using HEC-HMS to simulate precipitation-runoff process. SRTM 90m resolution DEM is used for delineation of basin which is downloaded from CGIAR-CSI. River network is digitized by Google Earth. Arc map 10.1 is used for watershed delineation. In place of gauge rainfall, satellite estimated rainfall data is used. The Japan Aerospace Exploration Agency (JAXA) provide hourly data of precipitation in 0.1× 0.1-degree resolution observed by satellite. The simulation result is checked after real time data provided by BWDB at Kurigram station. The value of correlation coefficient (R2) for calibration period (2009-2012) and validation period (2013-2014) are 0.71 and 0.81 respectively. From six-year model simulation, it is found that peak discharge occurred at 2 August, 2014. The value of peak flow is 4515.4 cumec. At the time of peak flow, volume passes through outlet is 38928 million m3.From calibration and validation graph we can see that the model gives satisfactory result at dry period. At the time of high discharge, model result shows more deviation from observed data. So, GSMaP is more reliable at dry season ABSTRACT Drought is considered as one of the major natural hazards that affect the environment and economy of a country. Different from other natural disasters, drought events appear slowly in time and their impacts generally span over a longer period of time. Weather data alone is not sufficient to monitor and evaluate the areas of drought, particularly when those data are rare and incomplete. Enhancement of weather data with satellite images to identify the location and severity of droughts are important for complete, up-to-date and comprehensive coverage of current drought conditions. The objective of this research is to monitor and understand meteorological drought using Standard Vegetation Index (SVI) and Vegetation Condition Index (VCI). Another objective is to measure the accuracy of two method’s result by analyzing the changes in precipitation data. For this, SVI and VCI are derived from EVI and NDVI, which are obtained by analyzing MODIS (moderate-resolution imaging Spectroradiometer) data at 250m spatial resolution during July and August month of each year from 2000 to 2016 at 2 years interval. The study result shows the percentage of area affected by drought and its severity on the selected years. It also helps to understand how vegetation condition is being changed over time. etc.