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Extreme Flooding Events Assessment Using Remote Sensing and GIS. MS Thesis Remote Sensing and GIS Presented By Syed Hammad Shabbir CIIT\FA13-RRG-010\ISB Supervisor: Dr Aqeel Ahmed Kidwai COMSATS Institute Of Information Technology Islamabad Sequence of Presentation Introduction Methodology Result Discussion Conclusion Recommendations Introduction To provide an assessment of extreme flood events in Pakistan under predicted climate change scenarios The severe flooding and its impact on social and economic conditions of people living around the vulnerable areas around Indus Basin. To examine different flood events and their potential impact on the floodplains Defining Indus Basin and its catchment area, sub basins within the boundaries of Pakistan Floodplain mapping and inundation maps Study Area Indus River Historically known as Sindhu, Sindhi also called Mehran in Sanskrit and Tibetan language. One of the longest river of the world. It is ranked as the twelfth largest river basin on Earth Passing through the Himalayan, Karakorum and Hindu Kush ranges it has total length of 3200 Km The drainage area is about 1,165,000 sq km. The 453,000 square km area of basin is in the Himalayas Ranges, the Hindu Kush, and the Karakoram Range The other part is in the plains of Pakistan Indus River (Study Area) http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=46369 The annual flow of the river is around 243 cubic km Geological history shows that 50 to 45 million years ago Indus River Delta emerged as a delta and the river in fifty million years has twice changed its course and direction. Upper Indus Basin (UIB) has approximately 220,000 square kilometer (km2) surface area. Major tributaries of Indus Basin are Chenab, Jhelum, Ravi, Sutlej and Kabul River Glaciers runoff contributes approximately 19.6 million acre-feet (MAF) to the total annual flow of the UIB. 14.1 MAF from the Karakorum, 2.3 MAF from western Himalayas and 3.2 from the Hindu Kush. 18 percent of the total flow of 110 million acre-feet (MAF) from the mountain headwaters of Indus River and the 82 percent is from melt water from winter snow. Climate change and the Indus River Pictures AFP/ Getty Images The most vulnerable people affected with climate change will be the poorest people of developing countries. Indus River have been affected by frequent and high intensity floods in recent years. Historical patterns and trends in temperature and precipitation indicate increasing hydro climatic risks in Pakistan over the coming years. By the 2020s the temperature is expected to rise by about 2°C in northern Pakistan, 1.5°C in the central parts of the country, and 1°C in the coastal areas. Have negative affect over the glaciers of UIB which will increase the rate of snow melting, increased frequency and intensity of floods. Sequence and Damages from flood events in Pakistan Damages from July 2010 flood event AFP/ Getty Images In 2010 Pakistan experienced catastrophic monsoon and extraordinary rainfall in midJuly to September 2010 resulting in unprecedented floods affecting the entire country. This was the second worst event in terms of devastation since 1929. Rains and floods affected over 20 million people, destroying the properties, housing, infrastructure and crops. The estimated cost was 10 billion US$ for reconstruction. METHODOLOGY Defining the catchment area of Indus Basin with watershed delineation analysis. Hydraulics modeling using geometric input data for modeling. Historical extreme flood events modelling. Flood modeling of 22 July 1958 for Dera Ghazi Khan Division Flood modeling of 02 August 2010 for Dera Ghazi Khan Division Flood modeling of 15 August 1976 for Sukkur, Larkana and Nasirabad Divisions Flood modeling of 08 August 2010 Sukkur, Larkana and Nasirabad Divisions METHODOLOGY Defining Indus Basin By using the Arc Hydro tools define the catchment area of Indus River, its floodplains and streams network. The points used for the delineation are of major barrages of Pakistan. Watershed delineation analysis for Tarbella Dam Mangla Dam Chashma Barrage Taunsa Barrage Trimmu Jehlum Link Trimmu Chenab Link Panjnad Barrage Guddu Barrage Kotri Barrage Indus Basin Drainage Analysis To perform drainage analysis digital elevation model (DEM) of Global Multiresolution Terrain Elevation Data 2010 (GMTED2010) 15 arc-seconds is used. For the hydrologic modeling the break line layers were used; the breakline emphasis products are recommended layers for hydrology projects. The images were mosaicked in Erdas Imagine 2011, Pakistan was extracted from the mosaic image using ArcMap spatial analyst tool. Project to projected coordinate system UTM using project tool in ArcMap. Arc Hydro tools are useful in hydrologic modeling Steps in Drainage Analysis Fill Sinks Flow Direction Flow Accumulation Batch Watershed Delineation Stream Definition Drainage Area Centroid Stream Segmentation Longest Flow Path Catchment Grid Delineation Construct 3D Line Catchment Polygon Processing Drainage Line Processing Smooth 3D Line Adjoint Catchment Processing Hydro Network Generation Drainage Point Processing Node/Link Schema Generation Longest Flow Path for Catchments Compute Local Parameters Longest Flow Path for Adjoint Catchments Generate Report Slope Steps Watershed Maps Hydraulic Analysis Define the floodplains of the Indus Basin and to create flood inundation maps. Areas are selected for the hydraulic analysis Dera Ghazi Khan Division Sukkur Division Larkana Division Nasirabad Division Demographics Rahim Yar Khan, Muzaffargarh, D.G.Khan and Rajanpur are classified in the high deprived category. Kashmore, Jaccobabad, Jamshoro, Tando Muhammad Khan, Umer Kot, Badin, Thatta and Tharparkar for the Sindh province are high level of deprivations magnitude of overall Index of multiple deprivations according to the Districts’ Indices of Multiple Deprivations A research study conducted by Plan International suggested based on fourteen different parameters that Dera Ghazi Khan Division, Sukkur Division and Larkana Divisions are amongst the most vulnerable and insecure regions for the flooding (Neighboring Risk 2010). Hydraulic Modeling and Floodplain Mapping with HEC-GeoRAS and HEC-RAS HEC-GeoRAS is software developed by US Army Corps of Engineers Institute for Water Resources as an extension for ArcGIS. The tools are used to build geometric data for river analysis. The geometric files are exported to HEC – RAS and then imported back for Inundation maps. HEC – RAS is software developed by US Army Corps of Engineers Institute for Water Resources. The Hydrologic Engineering Centers River Analysis System (HEC-RAS) is developed to perform one-dimensional steady flow analysis it also perform unsteady flow analysis, sediment transport computations, and water temperature modeling. (USACE, 2002 b). Process flow diagram of HEC-RAS Analysis Start an ArcGIS Project TIN Stream Center Line Prepare Geometric Data Bank Lines Flowpath Lines Start RAS Project Import Geometric Data Extract Elevation Data Export RAS Data Cross Section Review Enter Flow Data ArcGIS Project Create Profiles for Steady Flow Analysis Import RAS Results Create Flood profile maps Inundation Maps Export GIS File Spatial Data preparation DEM Dera Ghazi Khan Division and TIN Dera Ghazi Khan Division Spatial Data preparation DEM Nasirabad – Larkana - Sukkur Division & TIN Nasirabad – Larkana - Sukkur Division Importing Geometry data into HEC-RAS The geometric file created in HEC-Geo RAS is now imported into HEC – RAS as GIS import file HEC-RAS can perform steady and unsteady flow water surface profile calculations, sediment transport computations, and water temperature analysis (USACE, 2002 b). Modeling in HEC-RAS Subcritical analysis was used to perform floodplain and inundation mapping. Flow Data and boundary conditions. The historical flow data of past extreme flood events were collected from the Federal Flood Commission Report 2010. The flow data used to perform this analysis was from Tanusa Barrage data i.e. 7,88,646 for 22 July 1958 and 9,59,991 cusecs for 02 August 2010 was considered for Dera Ghazi Khan Division and Guddu Barrage i.e. 11,99,672 cusecs for 15 August 1976 and 11,31,000 cusecs for 08 August 2010 for the Sukkur, Larkana and Nasirabad Divisions. Normal depth was used for the boundary condition. Modeling in HEC-RAS Two plans of flow data entered for the Dera Ghazi Khan Division first was historical flow data of 22 July 1958 i.e. 7,88,646 cusecs and 9,59,991 cusecs for 02 August 2010 for Tanusa Barrage. For the second analysis the historical flow data of 15 August 1976 i.e. 11,99,672 cusecs and 11,31,000 cusecs for 09 August 2010 for the Guddu Barrage. The cusecs were converted into cubic meter/second as a requirement of the SI units. Steady Flow Analysis Subcritical flow regime was selected for this analysis. The RAS file was exported as GIS data with all the computed profiles to be used for flood inundation mapping. Flood inundation mapping RESULTS The areas severely affect by these results are Layyah, Kot Addu, Muzaffargarh and Jampur. Rajanpur was not included in the final result because the analysis was done up till the divisional boundaries of the river. Results in Tabular format and Graphical Profiles Flood 22 July 1958 Profile 1 Output Table, RAS Modeling Flood 22 July 1958 Profile 1 X-Y-Z Perspective RAS Modeling Results in Tabular format and Graphical Profiles Flood 22 July 1958 Profile 2 Output Table, RAS Modeling Flood 2010Profile 2 X-Y-Z Perspective RAS Modeling Flood inundation mapping Flood 22 July 1958 Floodplain Map RAS Modeling Flood 22 July 1958 Depth Map RAS Modeling Flood inundation mapping Flood 02 August 2010 RAS Modeling Flood 02 August 2010 Depth Map RAS Modeling Flood inundation mapping Flood 08 August 2010 RAS Modeling Flood 15 August 1976 RAS Modeling Results comparison Dera Ghazi Khan Flood 02 August 2010 Landsat Image 12 August 2010 Flood 2010 UNDP Shapefile Results comparison Floodplain extent 2010 RAS Modeling Rivers and Canals System Sukkur, Nasirabad and Larkana Divisions Conclusion The most vulnerable districts to be affected by the floods every year are the most poorest districts of Pakistan. The social and economic conditions in these districts are at lowest level. The Human development Index of these districts are among the lowest. The chances to recover from floods for these districts are very low without external help. Catchments, sub catchments with drainage lines of stream network with delineation points helps to work on specific floodplain. The final results can be used for the hazard mapping and mitigation purpose. The velocity, power, shear and depth of the flood is calculated in the final results. ArcGIS and River Analysis Systematic Tools provided the prospect to complete this study by using historical data of the floods. Model historical extreme or predicted flood event by using these tools. Meteorological data can be added to create time series floodplain mapping Limitations Cross section data TIN data Bridges and Culverts data Ineffective flow areas Obstructions Boundary Conditions Levees and embankment data Comparison Maps RECOMMENDATIONS Geo-referenced surveyed data for the cross section can improve the quality and accuracy of the final results. LiDAR data for the TIN creation is recommended for the analysis as LiDAR data is more accurate and detailed than the Digital Elevation Models. Bridges data with their heights and width as input for geometric data preprocessing can improve the results. Obstructions and other blocked areas including lakes and canal data can also impact the final results of the analysis. Similarly the embankments on the river sides can also impact the results the height and width of these embankments can affect the results. Flow change locations and factors like time series data, precipitation data at the time of flood in particular catchment area can also improve the final results of floodplain mapping. REFERENCES Arshad, R.R. (2010). Pakistan Floods 2010. Preliminary Damage and Needs Assessment Dragan, S., Slobodan P. S. (2009). Vulnerability of Infrastructure to Climate Change, Background Report 2 - Hydraulic Modeling and Floodplain Mapping. City of London. EM – DAT: CRED International Disaster Database, http://www.emdat.be, 2015. Eum, H.I., Simonovic. S. P. (2009). Vulnerability of Infrastructure to Climate Change, Background Report 1 – Climate and Hydrologic Modeling. The City of London. FFC (2010). Federal Flood Commission Annual Flood Report 2010. Jie, Y., Ronald, D.T., Bahram, D. (2006). Applying the HEC-RAS model and GIS techniques in river network floodplain delineation Khadija, Z., Anna, C. (2014). How the people of Pakistan live with climate change and what communication can do. The Climate Asia Report 2014. Meyer, S., Olivera, F. (2007). “Floodplain Mapping & Hydraulic Analysis with HEC-GeoRAS 4.1.1 and ArcGIS 9.1.” Retrieved from: https://ceprofs.civil.tamu.edu/.../GeoRAS411/ Nasser, M. (2010). Malevolent Floods of Pakistan 2010-2012. SPO NATIONAL CLIMATE CHANGE POLICY. GOVERNMENT OF PAKISTAN, Ministry of Environment. Draft National Climate Change Policy, 2011. USACE (2005). HEC-GeoRAS, GIS Tools for support of HEC-RAS using ArcGIS, User’s Manual, Version 4. United States Army Corps of Engineers, Hydrologic Engineering Centre, Davis, California. USACE (2006). HEC-RAS, River Analysis System, User’s Manual, Version 4.0. United States Army Corps of Engineers, Hydrologic Engineering Centre, Davis, California. Winston, Y., Yi-Chen, Y., Andre, S., Donald, A., Casey, B., James, W., Dario, D., Sherman, R. (2010). The Indus Basin of Pakistan. The Impacts of Climate Risks on Water and Agriculture. Young, W.P. (2013). 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