Dr. Muhammad Zia ur Rahman Hashmi, Senior Scientific Officer Global - PowerPoint PPT Presentation

presented by Dr. Muhammad Zia ur Rahman Hashmi, Senior Scientific Officer Global Change Impact Studies Centre (GCISC) SDPI’s Sustainable Development Conference (SDC), 9-11 Dec, 2014

Presentation layout  Introduction  Study area and data  Methodology  Results  Conclusions  Way forward

Introduction

Climate Change Impacts on Indus River Delta The Indus Delta is considered as one of the world's most threatened large deltas due to;  Climate change induced threats to the existence of Hindukush-Karakorum-Himalaya (HKH) glaciers feeding River Indus  Increasing upstream freshwater diversions to a vast irrigation network The Indus Delta having 160,000 hectare area covered with Mangroves

Mangroves of Pakistan  Coast line of Pakistan is 1050 km long and 40-50 km wide (Sindh 350 Km; Baluchistan 700 km)  In Sindh mangroves occupy 97% of total mangroves in Pakistan extending from Korangi Creek in the north to Sir Creek in the South.  Indus Delta comprises of 17 major creeks  Largest arid climate mangroves in the world  Depended on freshwater supply from Indus (??)

Some functions of Pakistani mangroves are as under:  Support biodiversity  Provide food, fiber, shelter and breeding ground to prawns, shrimps, several fin fish and others. Annual export of these about US$4 billion.  Reduce wave action and protect coastlines, sea ports, from cyclones  Provide livelihood to local population (e.g. wood for heating and cooking)

Hydrological Impacts of Climate Change in relation to Mangroves Precipitation Decreases may reduce mangrove productivity, area, diversity, growth, and River flow and seedling survival, and changes in species composition favoring more salt tolerant species. Increases may help increase in mangrove area, diversity of mangrove zones, and mangrove growth rates in some species. Extreme Large storm impacts mass mortality in mangroves forests. climatic events I ncrease in hurricane intensity over the next century is likely to decrease in the average height of mangroves. Projected increases in the frequency of high water events could affect mangrove health and composition due to changes in salinity, inundation, and sediments. Flooding, caused by increased precipitation, or relative sea-level rise may result in decreased productivity, photosynthesis.

Specific Objective of the Study  Study aims to assess changes in land cover especially the all-important mangrove forests of a selected area of the Indus delta in response to changes in the local hydrological regime (e.g. wet, dry, flood) through comparing land cover status for various hydrologically significant years during a historical period of 1987 to 2011  Hydrological regime of the area includes both rainfall and the river flow regime

Study Area and Data

The Indus River System, Pakistan

Data  Study area---Keti Bunder, Indus River delta  Two types of hydrological data i.e. river flow and rainfall  10-daily discharge data: Indus River downstream Kotri Barrage  Period: 1976-77 to 2005-06  Annual Flow Volume: Indus River downstream Kotri Barrage  Period: 1976-77 to 2009-10  Source: IRSA  Rainfall daily data: Karachi rain gauge  Period: 1961-2010  Source: Pakistan Meteorological Department

Methodology

Flow volume (MAF)/Rainfall (mm X 10^-1) 100 10 20 30 40 50 60 70 80 90 0 1987-88 1988-89 1989-90 1990-91 1991-92 1992-93 1993-94 1994-95 1995-96 1996-97 1997-98 1998-99 1999-00 2000-01 2001-02 Flow 2002-03 2003-04 2004-05 2005-06 Rainfall 2006-07 2007-08 2008-09 2009-10

Step-1  Time instances for comparative analysis Year Hydrological significance 1992 A major flood event after few wet years before it Start of a drought that is ranked as the worst during the recent history of the 1998 country 2002 End of the drought period that started in 1998 2010 An extremely devastating flood event 2011 Post 2010-flood Satellite Acquisition Date Spatial Resolution Spectral Tide (m) Resolution height Landsat 30 1.5 April 27, 1992 7 Landsat 30 1.5 February 7, 1998 7 Landsat 30 1.5 December 11, 2002 7 Landsat 30 1 February 24, 2010 7 Landsat 1.5 January 10, 2011 30 7

Step-2  The land cover mapping - a recently introduced Object Based Image Analysis (OBIA) technique.  Spatial analysis  Image processing and interpretation: Digital Image Processing (DIP) software ERDAS Imagine 8.7 and Definien Developer 7.0 were used.  Land Cover Classification System (LCCS) software, developed by Food and Agriculture Organization (FAO) has been used for land cover standardization.  All the maps were developed in ArcGIS 9.3

Satellite images acquisition Satellite Acquisition Date Spatial Spectral Tide Resolution (m) Resolution height Landsat 30 1.5 April 27, 1992 7 Landsat 30 1.5 February 7, 1998 7 Landsat 30 1.5 December 11, 2002 7 Landsat 30 1 February 24, 2010 7 Landsat 1.5 January 10, 2011 30 7

Results

Temporal Changes of Mangrove Area Land Cover Area (ha) Classes 27-Apr-92 7-Feb-98 11-Dec-02 24-Feb-10 10-Jan-11 Dense Mangroves 2,132.28 904.05 2080.59 2,430.35 2,575.35 Medium Mangroves 1,201.50 724.05 1246.9 1,665.83 1,813.00 Sparse Mangroves 10,455.48 6,088.86 4981.29 6,020.20 6,761.00 An overall accuracy of 87.51% was achieved with a Kappa coefficient of 0.8671

Correlation analysis

Spatio-temporal Changes of Mangrove Cover  Land cover comparisons in three settings;  wet regime vs. start of a dry regime  start of drought regime vs. end of drought regime  before river flooding vs. after river flooding

Wet hydrologic regime vs. start of drought regime 13789.26 7716.96

Start of drought regime vs. end of drought regime 7716.96 8308.78

Before vs. after a major flood event 10116.38 11149.35

Hydrologic trends

 Mann Kendall trend test  Annual totals show a NOT significant show that this trend is decreasing trend Rainfall (mm) 100 200 300 400 500 600 700 800 0 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 Annual Total Rainfall 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Frequency of Kotri downstream flows

10-daily Kotri downstream flows (MAF) decreasing trend Average=0.89 MAF

Conclusions  Variation of Mangrove cover area has a high level of correlation with the variation of fresh water availability to the Indus delta  Analysis of rainfall data shows a negative trend over the period 1961-2010, though this is not statistically significant  Analysis of flow data of Indus River downstream of Kotri barrage shows availability of water from Indus River for a very short duration during the year and a decreasing trend  Hence, in terms of fresh water supplies, mangroves of the study area are stressed  Any decrease in rainfall or river flow or both under a future scenario will further aggravate the life of Indus delta mangroves and associated ecosystem  Degradation of mangrove forest cover will affect the livelihood of the local community and make the settlements and ecosystem therein more vulnerable to expectedly more frequent and more intense extreme hydrological events

Way forward  Analysis presented here will be updated by incorporating up-to-date flow record  Analysis of current hydrological regime of the study area will be linked to future projections of local temp, rainfall and river flow (Water budget) to see different future regimes under different climate change scenarios