Ecological assessment of the Indus Delta: Environmental flows under climate change scenarios Paper presented at 17 th Sustainable Development Conference, Islamabad 9-11 December 2014 Paper presented by Sadia M Ishfaq, SDPI On behalf of: Kashif M. Salik, M. Zia-ur-Rehman Hashmi, Waheed-ul- Zafar Zahdi, and Sadia Ishfaq
Outline • Background • Methodology • Research findings • Current state of aquatic ecosystems in Indus delta • E-flows • E-flows under future CC scenarios • Research limitations • Conclusions & Recommendations
Study area
Study Area • Delta Area: 600,000 ha (5 th largest) • Ecosystems: marshes, creeks, mudflats, riverine forests, lakes and mangroves • Biodiversity: 177 DELTAIC SPECIES 143 22 10 4 FISH BIRDS REPTILES MAMMALS MANGROVE PL. • Mangroves: 97% of Pakistan’s mangrove reserves • Fragmented mostly; only 1/5 th dense forest • 7 th largest mangroves and largest arid mangroves in the world; • Forest cover lost rapidly at 2% per annum (Dasgupta & Shaw 2013) • Rainfall: mostly during monsoon (July – September) • Source of freshwater: Indus River
Stu Study dy ar area ea: : Ind Indus us D Delta elta • Population: 1.2 million • Mainly Thatta and Badin districts of Sindh • Livelihoods: • Rise in human population -> rise in demand for water 135,000 dependent on mangrove NR • Largest contiguous irrigation network in the world => regulated river flows -> agriculture • Main sources (WWF Pakistan) • Economic growth - urbanization, industrialization • 90% = fisheries • Energy needs -> hydropower generation • 8% = agriculture • Deforestation; salt-water intrusion; pollution • 2% = services • Economy: export of over 100,000 metric tones of fish (Rs25.7 billion) • $1.8million worth of fodder & fuelwood (IUCN Pakistan 2002)
THREATS FROM CLIMATE CHANGE Changes in Temperature Changes in CO 2 concentration Variability in Precipitations Occurrence of extreme weather events Changes in Sea Level rise Ocean circulation patterns Source: Syvitski et al, 2009
Environmental flows (E-flows) • Amount of Indus river flows required to sustain healthy ecosystems in Indus delta • Water flows determine physical, chemical and biological health of rivers • ‘magnitude, frequency, duration, timing, rate of change’ Biotic Water flows Physical habitats composition
E-flow assessment methods ORGANISATION CATEGORISATION OF METHODS SUB-CATEGORY IUCN Methods Look-up tables (DYSON ET AL 2003) Desktop analyses Functional analyses Habitat modelling Approaches Frameworks WORLD BANK Perspective approaches Hydrological Index Methods (KING, BROWN & SABET 2003) Hydraulic Rating Methods Expert Panels Holistic Approaches Interactive approaches IWMI Hydrological index methods (THARME 2003) Hydraulic rating methods Habitat simulation methodologies Holistic methodologies
Defining Environmental Management Classes 1. What is the current status of aquatic ecosystems in Indus Delta? 2. What e-flows are required in Indus Delta under existing ecological conditions? 3. What e-flows will be required under different flow regimes of future climate scenarios, and what will be their impact on Indus Delta? Adapted from Smakhtin et al 2007
Indicators for first question: assessment of current state of aquatic ecosystems in the Delta Indicator Justification Range Score Endangered Total No. of endanger spc. as % of the Very High 5 aquatic biota total no. of spc. in the delta. High 4 >20% endangered species — very high, Moderate 3 10 – 20% — high, 5 – 10% — moderate, 2 – Minor 2 5% — low and <2% — minor or none None 1 Unique aquatic Total No. of unique (endemic) spc. as % Very High 5 biota of the total no. of spc. in the delta. High 4 >20% endangered U.species — very high, Moderate 3 10 – 20% — high, 5 – 10% — moderate, 2 – Minor 2 5% — low and <2% — minor or none None 1 Diversity of More habitat types are present, the Very High 5 aquatic habitats more incentives should be to preserve High 4 them to ensure the aquatic biodiversity Moderate 3 as well. Minor 2 None 1
Continue… Indicator Justification Range Score Presence of The more protected area then more >10% 5 protected areas E.flows is likely to be necessary for the 5-10% 4 delta for maintenance of aquatic life. 3-5% 3 1-3% 2 <1% 1 Sensitivity of Evaluated based on professional Very High 5 aquatic judgment: Assumption behind is that High 4 ecosystem to highly sensitive ecosystems need more Moderate 3 fresh water water to maintain them in business as Minor 2 flow reduction usual scenario. None 1
Cont … Indicator Justification Range Score Percentage of Can be estimated using RS images, from 70-100% 5 Delta remaining literature sources or based on field 50-70% 4 under natural surveys. These are measures of the 30-50% 3 vegetation extent of vegetation remained in the 10-30% 2 delta . >10% 1 Degree of flow It is the total dam storage capacity in a >100% 1 regulation basin as a % of the mean flow. 50-100% 2 These are important determinants of the 20-50% 3 habitat condition and aquatic 10-20% 4 biodiversity. 0-10% 5
Continue… Indicator Justification Range Score Percentage of the Many fish species move/travel distances along the 70-100% 1 50-70% 2 basin closed to rivers/canals during their life history requirement. 30-50% 3 movement of Therefore, dams/barrages disrupt longitudinal 10-30% 4 aquatic biota by connectivity and fragment population leading to >10% 5 structures decline in aquatic biodiversity. Plant species The number of species that present in delta Very High 5 High 4 relative richness should be expressed as a % of the number that Moderate 3 would be expected to occur there in the absence Minor 2 of human intervention. None 1 Human It may be seen as an aggregate indicator of human Very High 1 High 2 population pressure on aquatic ecosystems in delta. Moderate 3 density in the Low 4 entire Delta None 5 (pop/sq.km.) Class A Overall water 5 Related to Suitability of water: A=drinking, B= Class B 4 swimming/bathing; C =treatment before drinking; quality in delta Class C 3 D=for propagation of biodiversity; and E=only for Class D 2 irrigation or industrial purposes Class E 1
Indicator Assessment: Based on Extensive literature review Expert Interviews: conducted during April 2012 at different Governmental and Civil society organizations
Indicators related to question 1: Environmental Management Classes A sum of actual indicator EMC Most likely ecological condition scores as a percentage of (adapted from DWAF 1999) the maximum possible sum 91-100 A Natural rivers flows with minor modification and have natural stream flows and riparian habitat 75-90 B Slightly modified and /or ecologically important rivers with largely intact biodiversity and habitats despite water resources development and/ or basin modifications 50-74 C The habitats and dynamics of biota have been disturbed, but basic ecosystem functions are still intact. 30-49 D Large changes in natural habitat, biota and basic ecosystem functions have occurred. A clearly lower than expected species richness. Much lowered presence of intolerant species. Alien species prevail. 15-29 E Habitat diversity and availability have declined. A strikingly lower than expected species richness. Only tolerant species remain. Indigenous species can no longer breed. Alien species have invaded the ecosystem. 0-14 F Modifications have reached a critical level and ecosystem has been completely modified with almost total loss of natural habitat and biota. In the worst case the basic ecosystem functions have been destroyed and the changes are irreversible.
Approximation of EMC by total Indicators scores Ecological sensitivity and importance of a Delta Indicators Range Score Endangered aquatic biota Medium 3 Unique aquatic biota Very High 5 Diversity of aquatic habitats Very High 5 Presence of protected areas >10% 5 Sensitivity of aquatic ecosystem to fresh water Very High 5 flow reduction Indus River delta looks like at present, compared to a reference condition in the past Percentage of Delta remaining under natural 50-70% 3 vegetation Degree of flow regulation 10-20% 4 Percentage of the delta closed to movement 70-100% 1 of aquatic biota by structures Plant species relative richness Moderate 3 Human population density Low 2 Overall water quality in delta Class E 1 Sum of Indicator Score 38 Maximum possible Sum of Scores 55 Percent of The Maximum 69% Environment Management Class (EMC) C
Research question 2: Environmental flows required to sustain deltaic ecosystems -EFDCs FDC analysis of the reference flow and e-flows corresponding to each EMC
Climate Change and Environmental Water Needs of Indus Delta
Research question 3: E-flows under different future climate scenarios Scenario 1 • No decrease in Indus river flows until at least end of the 21 st century Possible range of increased river flow is: 46% (under RCP45 during 2021-2050) to 96% (RCP85 for 2071-2100) Source: (Immerzeel et al 2013) Scenario 2 • Flows will increased in early 21 st century (compared to baseline) – > rapid melting of Himalayan glaciers -> decrease in melting during later 21 st century Range of decrease in river flows of -40% to -65% Source: (Rees & Collins, 2006)
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