zhob river basin

159 Pages·2017·4.4 MB·English

by  Arif Samoon

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 ........................................................... 33
Figure 14 - Annual rainfall years having values above and below annual average rainfall
of Mula river basin of Balochistan ...................................................................... 34
Figure 15 - Maximum and minimum temperature changes for 2080s (Islam et al., 2009) .... 37
Figure 16 - Future Daily Flow plotted against Daily precipitation for Mula watershed. ......... 40
Figure 17 - Trends for decadal future precipitation for Mula watershed. .............................. 40
Figure 18 - Averaged monthly historic and future precipitation for Mula watershed. ............ 41
Figure 19 - Future Monthly average precipitation trends for Mula watershed. ..................... 42
Figure 20 - Annual average historic and future precipitation for Mula watershed. ................ 43
Figure 21 - Future Daily Flow versus Precipitation for Zhob watershed. .............................. 44
Figure 22 - Future Decadal precipitation trends for Zhob watershed. .................................. 44
Figure 23 - Averaged monthly historic and future precipitation for Zhob watershed. ............ 45
Figure 24 - Future Monthly average precipitation for Zhob watershed. ................................ 45
Figure 25 - Historic and Future Annual average precipitation for Zhob watershed. .............. 46
Figure 26 - Future Monthly average minimum temperature for Zhob watershed. ................. 47
Figure 27 - Future Monthly average maximum temperature for Zhob watershed. ................ 48
Figure 28 - Historic and future Daily Maximum Temperature for Zhob watershed. .............. 48
Figure 29 - Historic and future Daily Minimum Temperature for Zhob watershed. ............... 49
Figure 30 - Future decadal Maximum temperature for Zhob Watershed.............................. 49
Figure 31 - Future decadal Minimum temperature for Zhob Watershed. ............................. 50
Figure 32 - Historic and future averaged monthly maximum temperature for Zhob
watershed. ......................................................................................................... 51
Figure 33 - Historic and future averaged monthly minimum temperature for Zhob
watershed. ......................................................................................................... 51
Figure 34 - Historic and Future daily maximum temperature for watershed. ........................ 52
Figure 35 - Historic and Future daily minimum temperature for watershed. ......................... 52
Figure 36 - Future decadal maximum temperature for watershed. ...................................... 53
Figure 37 - Future decadal minimum temperature for Mula watershed. ............................... 54
Figure 38 - Maximum (A) and Minimum (B) temperature moving average for the projected
time series for Zhob Watershed. ........................................................................ 55
Figure 39 - Maximum (A) and Minimum (B) temperature moving average for the projected
time series for Mulla Watershed. ........................................................................ 56
Figure 40 - Maximum (A) and Minimum (B) temperature moving average for the projected
time series for Mulla Watershed. ........................................................................ 57
Figure 41 - Highest seven Precipitation Years for Mula Watershed (A) ............................... 60
Figure 42 - Highest seven Precipitation Years for Mula Watershed (B) ............................... 60
Figure 43 - Sub Basin Level Point Flood Map of Zhob Watershed ...................................... 62
Figure 44 - Sub Basin Level Point Flood Map of Mula Watershed ....................................... 63
Figure 45 - Floods in Zhob and Mula river basins of Balochistan in last 35 years. ............... 67
Figure 46 - Droughts in Zhob and Mula river basins in last 35 years. .................................. 68
Figure 47 - Sediment yield at watershed outlet (Zhob Watershed) ...................................... 70
Figure 48 - Sediment Yield at Nawar Dam Location (Zhob Watershed) .............................. 70
Figure 49 - Sediment Yield at Nawar Dam location (Zhob Watershed). ............................... 71
Figure 50 - Sediment Yield at Watershed outlet (Mula Watershed). .................................... 71