Ecological assessment of the Indus Delta: Environmental flows under - - PowerPoint PPT Presentation

Ecological assessment of the Indus Delta: Environmental flows under climate change scenarios

Paper presented at 17th 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 (5th largest)
• Ecosystems: marshes, creeks, mudflats, riverine forests, lakes and mangroves
• Biodiversity:
• Mangroves: 97% of Pakistan’s mangrove reserves
• Fragmented mostly; only 1/5th dense forest
• 7th 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

177 143 22 10 4 FISH BIRDS REPTILES MAMMALS MANGROVE PL.

DELTAIC SPECIES

Stu Study dy ar area ea: : Ind Indus us D Delta elta

• Population:

1.2 million

• Mainly Thatta and Badin districts of Sindh
• Livelihoods:

135,000 dependent on mangrove NR

• Main sources (WWF Pakistan)
• 90% = fisheries
• 8% = agriculture
• 2% = services
• Economy: export of over 100,000 metric tones of fish

(Rs25.7 billion)

• $1.8million worth of fodder & fuelwood (IUCN Pakistan 2002)
• Rise in human population -> rise in demand for water
• Largest contiguous irrigation network in the world => regulated river flows -> agriculture
• Economic growth - urbanization, industrialization
• Energy needs -> hydropower generation
• Deforestation; salt-water intrusion; pollution

Source: Syvitski et al, 2009

THREATS FROM CLIMATE CHANGE Changes in Temperature Changes in CO2 concentration Variability in Precipitations Occurrence of extreme weather events Changes in Sea Level rise Ocean circulation patterns

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’

Water flows Physical habitats Biotic composition

E-flow assessment methods

ORGANISATION CATEGORISATION OF METHODS SUB-CATEGORY IUCN (DYSON ET AL 2003) Methods Look-up tables Desktop analyses Functional analyses Habitat modelling Approaches Frameworks WORLD BANK (KING, BROWN & SABET 2003) Perspective approaches Hydrological Index Methods Hydraulic Rating Methods Expert Panels Holistic Approaches Interactive approaches IWMI (THARME 2003) Hydrological index methods 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 aquatic biota Total No. of endanger spc. as % of the total no. of spc. in the delta. >20% endangered species—very high, 10–20%—high, 5–10%—moderate, 2– 5%—low and <2%—minor or none Very High High Moderate Minor None 5 4 3 2 1 Unique aquatic biota Total No. of unique (endemic) spc. as %

• f the total no. of spc. in the delta.

>20% endangered U.species—very high, 10–20%—high, 5–10%—moderate, 2– 5%—low and <2%—minor or none Very High High Moderate Minor None 5 4 3 2 1 Diversity of aquatic habitats More habitat types are present, the more incentives should be to preserve them to ensure the aquatic biodiversity as well. Very High High Moderate Minor None 5 4 3 2 1

Continue…

Indicator Justification Range Score Presence of protected areas The more protected area then more E.flows is likely to be necessary for the delta for maintenance of aquatic life. >10% 5-10% 3-5% 1-3% <1% 5 4 3 2 1 Sensitivity of aquatic ecosystem to fresh water flow reduction Evaluated based on professional judgment: Assumption behind is that highly sensitive ecosystems need more water to maintain them in business as usual scenario. Very High High Moderate Minor None 5 4 3 2 1

Cont…

Indicator Justification Range Score Percentage of Delta remaining under natural vegetation Can be estimated using RS images, from literature sources or based on field

• surveys. These are measures of the

extent of vegetation remained in the delta. 70-100% 50-70% 30-50% 10-30% >10% 5 4 3 2 1 Degree of flow regulation It is the total dam storage capacity in a basin as a % of the mean flow. These are important determinants of the habitat condition and aquatic biodiversity. >100% 50-100% 20-50% 10-20% 0-10% 1 2 3 4 5

Continue…

Indicator Justification Range

Score Percentage of the basin closed to movement of aquatic biota by structures Many fish species move/travel distances along the rivers/canals during their life history requirement. Therefore, dams/barrages disrupt longitudinal connectivity and fragment population leading to decline in aquatic biodiversity.

70-100% 50-70% 30-50% 10-30% >10% 1 2 3 4 5

Plant species relative richness The number of species that present in delta should be expressed as a % of the number that would be expected to occur there in the absence

• f human intervention.

Very High High Moderate Minor None 5 4 3 2 1

Human population density in the entire Delta (pop/sq.km.) It may be seen as an aggregate indicator of human pressure on aquatic ecosystems in delta.

Very High High Moderate Low None 1 2 3 4 5

Overall water quality in delta Related to Suitability of water: A=drinking, B= swimming/bathing; C =treatment before drinking; D=for propagation of biodiversity; and E=only for irrigation or industrial purposes

Class A Class B Class C Class D Class E 5 4 3 2 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 scores as a percentage of the maximum possible sum EMC Most likely ecological condition (adapted from DWAF 1999) 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

• ccurred. 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 flow reduction Very High 5 Indus River delta looks like at present, compared to a reference condition in the past Percentage of Delta remaining under natural vegetation 50-70% 3 Degree of flow regulation 10-20% 4 Percentage of the delta closed to movement

• f aquatic biota by structures

70-100% 1 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

Scenario 1

• No decrease in Indus river flows until at least end of the 21st 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 21st century (compared to baseline) –> rapid melting of

Himalayan glaciers -> decrease in melting during later 21st century Range of decrease in river flows of -40% to -65% Source: (Rees & Collins, 2006)

Research question 3: E-flows under different future climate scenarios

CC Scenario 1

E-flows FDC under CC scenario 1 E-flows under CC scenario 1

CC Scenario 1

Normal variability

Possibility of transformation of Indus Delta into a higher EMC

Extreme variability

While the EMC of the delta ecology may be theoretically high, practically deltaic ecosystems may be ill-suited to the changed climate conditions

• Fluctuations in glacial melt -> fluctuating runoff water and

sediment -> reduce water quality -> hindered biological absorption of dissolved nutrients -> reduced ability to provide valued ecosystems services -> dependent communities affected

Increased river flows Decline in soil salinity (mangrove) Spurred growth of less-salt tolerant sp Species richness & improved

• ecol. status

Improved agricultural productivity & fisheries Improved livelihoods, food security Local communiti es benefit

CC Scenario 2

E-flows FDC under CC scenario 2 E-flows under CC scenario 2

CC Scenario 2

High socioeconomic and environmental vulnerability to climate change with significantly downscaled EMC of Indus delta

Reduced river flows More e-flow required to maintain healthy ecosys Aggravated loss of mangroves Degraded aquatic habitats & ecosys Decline in agricultural productivity & fisheries Revenue losses Poorer communiti es more vulnerable

Limitations

• Difficulty of verifying and isolating river flows and deltaic

ecosystems as independent variables.

• Given the complex interrelationship of dynamic systems of flow

regime, freshwater ecology, CC and human intervention, it is almost impossible to separate biotic response to flows from other influences that may alter biotic diversity.

• We look at long-term variability -> overlook considerations such as

whether aquatic biota would evolve gradually over a longer period of time, to adapt to modified flows, or whether they would behave more sporadically and unpredictably in response to daily fluctuations in river flows. If the current deterioration of aquatic ecology continues, it will be challenging to maintain present, or achieve higher, ecological class, regardless of the changes in river flows in the future

Bridging the gaps

National

• Interlink and balance economic and development needs with environmental

needs

• Institutional collaboration (MoWP, MoE/CCD, EPA, local municipalities, communities)
• Build capacity and expand opportunities available to locals for improved, and

environmentally sustainable incomes

• Will contribute to development, protection and preservation of riverine and estuarine

ecosystems.

• Allow for environmental allocations in all water regulating sites
• Ensure e-flows (escapages to sea) – as committed in important water agreements
• New water infrastructure when designed/planned could introduce innovative structures that

mitigate/minimize disruptions in biotic connectivity

• Improved flood management

Trans-boundary

• Incorporate e-flows in IWT for rivers where minimum e-flows are not released

(Ravi, Beas and Sutlej)

• Any project plan on the shared river must carry out environmental flow

vulnerability assessments

Thank you!

sadiaishfaq@sdpi.org kashif.salik@gmail.com mhas074@aucklanduni.ac.nz