Balochistan Water Resources Development Sector Project (RRP PAK 48098) Supplementary Linked Document 25: Climate Risk and Vulnerability Analysis Report The Government of Balochistan Balochistan Water Resources Development Project Preparatory Technical Assistance (TA 8800-PAK) CLIMATE RISK AND VULNERABILITY ANALYSIS REPORT November 2017 Table of Contents 1 INTRODUCTION ........................................................................................................... 1 2 METHODOLOGY ........................................................................................................ 13 2.3.1 SWAT (Soil and Water Assessment Tool) ......................................................... 15 3 RESULTS OF CLIMATE CHANGE ANALYSIS .......................................................... 21 3.1.1 Statistical tests .................................................................................................. 21 3.1.2 Extreme event analysis ..................................................................................... 24 3.1.3 Water availability in extreme years of Zhob river basin ...................................... 26 3.1.4 Above and below average rainfall events .......................................................... 28 3.1.5 Statistical tests .................................................................................................. 29 3.1.6 Extreme event analysis ..................................................................................... 31 3.1.7 Water availability in extreme years of Mula river basin ...................................... 33 3.1.8 Above and below average rainfall events .......................................................... 34 3.2.1 Results of GCM Analysis ................................................................................... 39 4 VULNERABILITY ANALYSIS ..................................................................................... 64 4.5.1 Sediment ........................................................................................................... 69 5 ADAPTATION STRATEGIES ...................................................................................... 74 5.3.1 Dam additional freeboard .................................................................................. 77 5.3.2 Flood protection bund additional freeboard ........................................................ 77 5.3.3 Watershed Management ................................................................................... 78 5.3.4 Water storage system........................................................................................ 78 5.3.5 Cost of adaptations ........................................................................................... 78 5.4.1 Flood ................................................................................................................. 79 5.4.2 Drought ............................................................................................................. 80 5.4.3 Community coping mechanisms and enhancement of disaster resilience.......... 80 6 CONCLUSION AND MESSAGE FOR THE PPTTA TEAM.......................................... 82 REFERENCES ................................................................................................................... 83 ANNEXURE A- HISTORIC FLOOD INUNDATION MAPS.................................................. 86 ANNEXURE B-TEMPERATURE ANALYSIS GRAPHS ..................................................... 92 ANNEXURE C-METHODOLOGY OF ANALYSIS ............................................................ 122 ANNEXURE D-RESULTS OF STATISTICAL TESTS ...................................................... 124 ANNEXURE E- RESULTS OF GCM BASED DROUGHT AND FLOOD ANALYSES ...... 130 ANNEXURE F- DESIGN ADAPTATIONS FOR CLIMATE CHANGE ............................... 145 List of Tables Table 1 - Water balance of Balochistan for surface and groundwater resources (After ADB TA-4560 PAK 2008 by Ahmad 2016) ............................................................... 4 Table 2 - Climate Change adaptation policy for Balochistan as suggested in “Framework for Implementation of Climate Change Policy 2014 - 2030” (GOP, 2013) .............. 10 Table 3 - List of available meteorological stations, and data length for Zhob and Mula river basins of Balochistan ..................................................................................... 14 Table 4 - Calibrated Water balance for Zhob river basin of Balochistan ............................... 17 Table 5 - Calibrated Water balance for Mula river basin of Balochistan ................................ 18 Table 6 - Surface and groundwater availability under five flood years in the Zhob river basin of Balochistan .............................................................................................. 25 Table 7 - Surface and groundwater availability under 5 drought years in Zhob river basin of Balochistan ........................................................................................................ 26 Table 8 - Surface and groundwater availability in flood years in the Mula river basin of Balochistan ............................................................................................................ 32 Table 9 - Results of drought scenarios in Mula river basin of Balochistan ............................ 32 Table 10 - Slope values of future decadal precipitation based on linear regression trend lines for Mula watershed. ....................................................................................... 41 Table 11 - Slope values of future monthly average precipitation based on linear regression trend lines for Mula watershed. ............................................................ 42 Table 12 - Slope values of future monthly average temperature based on linear regression trend lines for Zhob watershed. ............................................................ 47 Table 13 - Slope values of future decadal temperature based on linear regression trend lines for Zhob watershed. ...................................................................................... 50 Table 14 - Slope values of future decadal temperature based on linear regression trend lines for Mula watershed. ....................................................................................... 53 Table 15 - Summary of results for Aridity index in Zhob and Mula watersheds. .................... 58 Table 16 - Summary of SPI analysis. ................................................................................... 59 Table 17 - Extreme Events (return periods) throughout the century for Zhob and Mula Watershed ............................................................................................................. 61 Table 18 - Flood Events (return periods) throughout the century for Zhob and Mulla Watershed ............................................................................................................. 61 Table 19 - Flood inundation modeling results for Zhob river basin of Balochistan ................ 67 Table 20 - Flood inundation mapping for the Mula river basin of Balochistan ....................... 67 Table 21 - Flood return periods for Zhob and Mula Watershed. ........................................... 70 Table 22 - Climate change vulnerability and impact matrix. .................................................. 72 Table 23 - Possible adaptation measures applicable in Zhob and Mula river basins. ........... 76 Table 24 - Proposed adaptations against possible climatic impacts ..................................... 77 Table 25 - Climate Change Adaptation Cost ........................................................................ 79 List of Figures Figure 1 - Major river basins of Balochistan .......................................................................... 3 Figure 2 - Agro-ecological zones with mean annual rainfall of Balochistan ............................ 5 Figure 3 - Brief outline of the study methodology ................................................................ 13 Figure 4 - Trend analysis of rainfall data for the Zhob river basin of Balochistan ................. 23 Figure 5 - Results of 3-year moving average of rainfall in the Zhob river basin.................... 24 Figure 6 - Histogram of rainfall (mm) for the Zhob river basin of Balochistan ...................... 25 Figure 7 - Internally generated floodwater in extreme flood, median and drought years in Zhob river basin of Balochistan. ......................................................................... 27 Figure 8 - Groundwater recharge in extreme flood year, median year and drought year in Zhob river basin of Balochistan. ......................................................................... 28 Figure 9 - Annual rainfall years having values above and below annual average rainfall of Zhob river basin of Balochistan. ......................................................................... 28 Figure 10 - Linear regression trend analysis on rainfall data for Mula river basin of Balochistan ........................................................................................................ 30 Figure 11 - 3-year moving average for rainfall in Mula river basin of Balochistan. ............... 31 Figure 12 - Histogram of rainfall (mm) for the Mula river basin of Balochistan. .................... 31 Figure 13 - Internally generated floodwater in extreme flood, median and extreme drought years of Mula River basin of Balochistan ..........................................................