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)

Precipitation and River flow Decreases may reduce mangrove productivity, area, diversity, growth, 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 climatic events Large storm impacts mass mortality in mangroves forests. Increase 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.

Hydrological Impacts of Climate Change in relation to Mangroves

 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

Specific Objective of the Study

Study Area and Data

The Indus River System, Pakistan

 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

Data

Methodology

10 20 30 40 50 60 70 80 90 100

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 2002-03 2003-04 2004-05 2005-06 2006-07 2007-08 2008-09 2009-10 Flow volume (MAF)/Rainfall (mm X 10^-1) Flow Rainfall

 Time instances for comparative analysis

Year Hydrological significance 1992 A major flood event after few wet years before it 1998 Start of a drought that is ranked as the worst during the recent history of the 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 (m) Spectral Resolution Tide height Landsat April 27, 1992 30 7 1.5 Landsat February 7, 1998 30 7 1.5 Landsat December 11, 2002 30 7 1.5 Landsat February 24, 2010 30 7 1 Landsat January 10, 2011 30 7 1.5

Step-1

 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

Step-2

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

Satellite images acquisition

Results

Land Cover Classes Area (ha) 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

Temporal Changes of Mangrove Area

Correlation analysis

 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

Spatio-temporal Changes of Mangrove Cover

Wet hydrologic regime vs. start of drought regime

13789.26 7716.96

Start of drought regime vs. end of drought regime

8308.78 7716.96

Before vs. after a major flood event

10116.38 11149.35

Hydrologic trends

100 200 300 400 500 600 700 800

1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 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

Rainfall (mm)

Annual Total Rainfall

 Annual totals show a

decreasing trend

 Mann Kendall trend test

show that this trend is NOT significant

Frequency of Kotri downstream flows

10-daily Kotri downstream flows (MAF)

Average=0.89 MAF decreasing trend

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