GIS BASED FLOOD MODELING: A CASE STUDY OF RIVER INDUS BETWEEN- GUDDU AND SUKKUR BARRAGES

Abstract

Exposure of Pakistan to natural hazards especially floods warrants use of latest technology to forecast the risk and vulnerabilities. GIS and Remote Sensing techniques can play a vital role in this regard. GIS based hydrological modeling provides solutions to predict different situations which can arise during the event of floods. This specialized GIS softwares based analysis approach has never been tested with its full capabilities in Pakistan. This research focuses on the preparation of calibrated model using recorded discharge / stage data during Floods 2010 between Guddu and Sukkur Barrages on River Indus. A high resolution contour (Sm) and satellite (1 Om) Digital Elevation Models are used as a base for integrating lay of ground with meticulously selected manning's coefficients for variable land use and land cover of the flood plain to calibrate the model in relation to actual recorded data. After integrating numerous factors including elevation, land use land cover, layout of embankments and river course of smaller area in ArcGIS the model was calibrated using steady flow analysis in HEC RAS. An accuracy of 8-10% in relation to recorded values was achieved and the model was then implemented on complete study area i.e. Guddu-Sukkur reach of River Indus. As a final result, inundation, water level and embankment vulnerability maps were generated using calibrated model.