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ENVIRONMENTAL FLOWS: 
THE CONCEPT AND APPLICATIONS IN INDIA 
VLADIMIR SMAKHTIN 
International Water Management Institute, ...
ENVIRONMENTAL FLOWS (EF) – WHAT IS THIS? 
• A compromise between water resources development and 
maintenance of a river i...
ENVIRONMENTAL FLOWS – WHERE ARE THEY? 
Potentially utilizable water (for 
agriculture, industry etc) 
Total resource capac...
ENVIRONMENTAL FLOW METHODOLOGIES 
• Hydrological (based on hydrological data and ecological perceptions) 
– % of MAR (e.g....
TWO-LEVELS’ EF ASSESSMENT FRAMEWORK 
Ideal for any country 
• DESKTOP : 
– Planning / Reconnaissance level 
– Limited deve...
IWMI EF WORK 
• Global, and in less exposed countries in Africa and Asia: 
India, Nepal, Sri Lanka, Ethiopia, Viet Nam, Az...
GLOBAL EF OUTLOOK 
estimated % of the annual river flow needed for ecological purposes 
AMAZON 
40 
35 
30 
25 
20 
15 
10...
ENVIRONMENTAL WATER SCARCITY 
Environmentally “safe” 
river basin 
Environmentally “water scarce” 
river basin 
Total wate...
GLOBAL ENVIRONMENTAL WATER STRESS INDEX 
Total withdrawals as a proportion of water available once EF are satisfied 
Total...
DESKTOP/ PLANNING EF APPROACH FOR INDIA 
• Combine flow variability with ecological management categories (EMC) 
to determ...
ENVIRONMENTAL MANAGEMENT CLASSES 
EMC ECOLOGICAL DESCRIPTION MANAGEMENT PERSPECTIVE 
A: Natural Pristine condition or mino...
LATERAL SHIFT OF A FLOW DURATION CURVE 
• A natural (reference) FDC is calculated from monthly flow time series 
• A shift...
EXAMPLES OF ESTIMATED EF DURATION CURVES 
100000.0 
10000.0 
1000.0 
100.0 
10.0 
100000.0 
10000.0 
1000.0 
100.0 
10.0 
...
ESTIMATES OF LONG-TERM EF VOLUMES AT 13 MAJOR RIVER 
BASIN OUTLETS FOR DIFFERENT EMC 
River Natural 
MAR, 
BCM* 
EF (% nat...
SIMULATING A TIME SERIES OF EF AT A SITE 
Once an EF FDC is established, a simple spatial interpolation procedure is used ...
EXTRACTS FROM ACTUAL AND SIMULATED TIME 
SERIES AT VIJAYAVADA (KRISHNA OUTLET) 
35000 
30000 
25000 
20000 
15000 
10000 
...
DESKTOP EF CALCULATORS 
Global, Ganges basin, Sri Lanka
OUTPUTS AND TOOLS AVAILABLE 
FOR USE / FURTHER REFINEMENT 
• An EF quick assessment methodology which could be replicated ...
DETAILED, PARTICIPATORY METHODS 
Upper Ganges, upstream of Kanpur 
• Collaboration between WWF-India – IWMI - IHE and othe...
BUILDING BLOCKS METHOD 
• BBM stages: 
– Reconnaissance, geomorphological survey, and EF sites selection 
– Biological and...
Zone 1 
Gangotri to 
Rishikesh 
Zone 3 
Narora to 
Farrukhabad 
21 
Zone 4 
Kannauj to 
Kanpur
EF SUMMARY, ZONE 1: GANGOTRI- RISHIKESH 
maintenance flows 
14000 
12000 
10000 
8000 
6000 
4000 
2000 
0 
Site EF1 -Kaud...
EF SUMMARY, ZONE 3: NARORA – FARRUKHABAD 
maintenance flows 
14000 
12000 
10000 
8000 
6000 
4000 
2000 
0 
Site EF3 –Kac...
PLANNING (GANGES CALCULATOR) AND 
COMPREHENSIVE (BBM) RESULTS COMPARED 
EF Site 
N 
EF Site 
Name 
EMC BBM Workshop 
resul...
SUMMARY 
• EF- is a tool to maintain a river in an agreed condition. EF need to 
mimic natural flow variability 
• A combi...
THANK YOU !THANK YOU !
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Environmental flows: The concept and applications in India

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Presented by Vladimir Smakhtin at the Ministry of Water Resources, New Delhi, India, November 4, 2014.

The flows of India’s rivers are increasingly being modified by dams and weirs and abstractions for agriculture and urban use. These interventions have caused significant alteration of flow regimes mainly by reducing total flow and affecting its variability and seasonality. An Environmental Flow (EF) is the water regime provided within a river, wetland or coastal zone to maintain ecosystems and their benefits. Environmental Flows describe the quantity, quality and timing of water flows required to sustain freshwater and estuarine ecosystems and the human livelihoods and well-being that depend on these ecosystems. This presentation looks at how the EF approach has been tested in India and describes a project to apply EF methodology to the upper Ganga.

Published in: Environment
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Environmental flows: The concept and applications in India

  1. 1. ENVIRONMENTAL FLOWS: THE CONCEPT AND APPLICATIONS IN INDIA VLADIMIR SMAKHTIN International Water Management Institute, Colombo, Sri Lanka Ministry of Water Resources, New Delhi, India, 4 November, 2014
  2. 2. ENVIRONMENTAL FLOWS (EF) – WHAT IS THIS? • A compromise between water resources development and maintenance of a river in an agreed / prescribed condition • Expressed as a set of flow releases / continuous hydrograph, which mimics the elements of natural flow regime • Different flows perform different environmental and social functions - elements of high, medium and low flows have to be included into EF • The more natural / healthy we want a river to be – – the more water, in total, we need to leave in it, – the more natural flow variability we need to maintain
  3. 3. ENVIRONMENTAL FLOWS – WHERE ARE THEY? Potentially utilizable water (for agriculture, industry etc) Total resource capacity, e.g. “natural” Mean Annual Runoff (MAR) Total volume of ENVIRONMENTAL FLOWS (varies depending on Desired Environmental Condition e.g. pristine, good, fair )
  4. 4. ENVIRONMENTAL FLOW METHODOLOGIES • Hydrological (based on hydrological data and ecological perceptions) – % of MAR (e.g.10% MAR - poor condition, 60% MAR - optimal) – low-flow indices from Flow Duration Curve (Q95, Q75...) – time series analyses (e.g. Range of Variability Approach –RVA) • Hydraulic rating or habitat simulation – simple relationships between a hydraulic variable (surrogate for habitat factors, e.g. wetted perimeter) and discharge – modelling of relationships between quantity and suitability of habitat for target species under different discharges • Holistic – take into account multiple environmental and social factors – require multidisciplinary panels of experts – Building Block Methodology (BBM)
  5. 5. TWO-LEVELS’ EF ASSESSMENT FRAMEWORK Ideal for any country • DESKTOP : – Planning / Reconnaissance level – Limited developments in a river basin – Quick and parsimonious • DETAILED : – Intermediate or comprehensive level (differ in data input) – High priority rivers, allocation tradeoffs – Data intensive, field data collection
  6. 6. IWMI EF WORK • Global, and in less exposed countries in Africa and Asia: India, Nepal, Sri Lanka, Ethiopia, Viet Nam, Azerbaijan • Primary focus - planning type assessment, based on Flow Duration Curves. More complex approaches in Viet Nam and India • Inclusion of EF in water allocation modeling
  7. 7. GLOBAL EF OUTLOOK estimated % of the annual river flow needed for ecological purposes AMAZON 40 35 30 25 20 15 10 5 30 25 20 15 10 5 • TO MAINTAIN A FAIR ECOLOGICAL CONDITION OF RIVERS WORLDWIDE, EF IN THE RANGE OF 20-50% OF MAR ARE NEEDED (ON AVERAGE, ABOUT 30%) 0 1 2 3 4 5 6 7 8 9 10 11 12 Months of the year % of the total annual flow LIMPOPO 0 1 2 3 4 5 6 7 8 9 10 11 12 Months of the year % of the total annual flow
  8. 8. ENVIRONMENTAL WATER SCARCITY Environmentally “safe” river basin Environmentally “water scarce” river basin Total water available Utilizable water Actual use Environmental needs Total water available Environmental needs Utilizable water Actual use tapping into environmental water needs
  9. 9. GLOBAL ENVIRONMENTAL WATER STRESS INDEX Total withdrawals as a proportion of water available once EF are satisfied Total water available Utilizable water Actual use Environmental needs
  10. 10. DESKTOP/ PLANNING EF APPROACH FOR INDIA • Combine flow variability with ecological management categories (EMC) to determine EF for different river conditions • Flow variability is represented by modified Flow Duration Curves – a cumulative distribution of discharges • A procedure is developed for assessment of the most suitable EMC using expert assessment and scoring of ecological indicators: – Rare and endangered aquatic biota (primarily fish) – Overall richness of aquatic species (fish) – Presence of protected areas – Degree of flow regulation – % of the basin remaining under natural cover types, – other
  11. 11. ENVIRONMENTAL MANAGEMENT CLASSES EMC ECOLOGICAL DESCRIPTION MANAGEMENT PERSPECTIVE A: Natural Pristine condition or minor modification of in-stream and riparian habitat Protected rivers and basins. Reserves and national parks. No new water projects allowed. B: Slightly modified Largely intact biodiversity and habitats despite water resources development and/or basin modifications. Water supply schemes or irrigation development present or allowed. C: Moderately modified The habitats and dynamics of the biota have been disturbed, but basic ecosystem functions are intact. Multiple disturbances associated with the need for socio-economic development, e.g. dams, diversions, etc D: Largely modified Large changes in natural habitat, biota and basic ecosystem functions have occurred. A clearly lower than expected species richness. Significant and clearly visible disturbances associated with basin and water resources development, including dams, diversions, transfers, habitat modification and water quality degradation E: Seriously modified Habitat diversity and availability have declined. A strikingly lower than expected species richness. Alien species have invaded the ecosystem. High human population density and extensive water resources exploitation. F: Critically modified Modifications have reached a critical level and ecosystem has been completely modified with almost total loss of natural habitat and biota. This status is not acceptable from the management perspective. Management interventions are necessary to restore flow pattern, river habitats etc (if still possible / feasible).
  12. 12. LATERAL SHIFT OF A FLOW DURATION CURVE • A natural (reference) FDC is calculated from monthly flow time series • A shift of 1 step is equivalent to “moving” a river from a higher EMC to the next (lower) one (e.g. from class ‘A’ to class ‘B’) 10000.0 1000.0 100.0 Direction of shift Reference (original) FDC 0.01 0.1 1 5 10 20 30 40 50 60 70 80 90 95 99 99.9 99.99 % Time f low exceeded Monthly Flow (MCM) Original A class B class C class D class A B C D
  13. 13. EXAMPLES OF ESTIMATED EF DURATION CURVES 100000.0 10000.0 1000.0 100.0 10.0 100000.0 10000.0 1000.0 100.0 10.0 1.0 0.1 MAHI OUTLET KRISHNA OUTLET 0.01 0.1 1 5 10 20 30 40 50 60 70 80 90 95 99 99.9 99.99 % Time f low exceeded Monthly Flow (MCM) Original A class B class C class D class Class E Class F 1.0 0.01 0.1 1 5 10 20 30 40 50 60 70 80 90 95 99 99.9 99.99 % Time f low exceeded Monthly Flow (MCM) Original Class A Class B Class C Class D Class E Class F
  14. 14. ESTIMATES OF LONG-TERM EF VOLUMES AT 13 MAJOR RIVER BASIN OUTLETS FOR DIFFERENT EMC River Natural MAR, BCM* EF (% natural MAR) Class A Class B Class C Class D Class E Class F Brahmaputra 585 78.2 60.2 45.7 34.7 26.5 20.7 Cauvery 21.4 61.5 35.7 19.6 10.6 5.8 3.2 Ganga 525 67.6 44.2 28.9 20.0 14.9 12.1 Godavary 110 58.8 32.2 16.1 7.4 3.6 2.0 Krishna 77.6 62.5 35.7 18.3 8.4 3.5 1.5 Mahanadi 66.9 61.3 34.8 18.5 9.7 5.6 3.6 Mahi 11.0 41.9 17.1 6.5 2.3 0.8 0.3 Narmada 45.6 55.5 28.8 14.0 7.1 3.9 2.5 Pennar 6.3 52.7 27.9 14.3 7.3 3.8 2.0 Tapi 14.9 53.2 29.9 16.6 9.0 4.9 2.6 Periyar 5.1 62.9 37.3 21.2 12.1 6.9 3.9 Sabarmati 3.8 49.6 24.2 12.1 6.6 3.7 2.1 Subarnarekha 12.4 55.0 29.9 15.4 7.4 3.4 1.5
  15. 15. SIMULATING A TIME SERIES OF EF AT A SITE Once an EF FDC is established, a simple spatial interpolation procedure is used to simulate the final output of the EF assessment- monthly EF time series
  16. 16. EXTRACTS FROM ACTUAL AND SIMULATED TIME SERIES AT VIJAYAVADA (KRISHNA OUTLET) 35000 30000 25000 20000 15000 10000 5000 0 1 11 21 31 41 51 61 Months since January 1991 Monthly flows (MCM) Observed at present Simulated natural EFR Class B EFR Class D Simulated Natural Observed EFR scenario 1 EFR scenario 2
  17. 17. DESKTOP EF CALCULATORS Global, Ganges basin, Sri Lanka
  18. 18. OUTPUTS AND TOOLS AVAILABLE FOR USE / FURTHER REFINEMENT • An EF quick assessment methodology which could be replicated in other basins and in the same basins – with addition data, at different reaches • Estimates of EF for each major basin outlet in the form of: – EF Duration Curves for each EMC, – Corresponding EF estimates as % of natural MAR – Corresponding EF monthly time series • Software tools (Ganges and Global EF Desktop calculators) • Publications (IWMI Research Reports, Water Policy Briefs, etc)
  19. 19. DETAILED, PARTICIPATORY METHODS Upper Ganges, upstream of Kanpur • Collaboration between WWF-India – IWMI - IHE and other partners • First time in India • Iconic river – lots of cultural and religious angles never explored before • Multidisciplinary (some 10 different specialists) • Modified Building Block Method (BBM)
  20. 20. BUILDING BLOCKS METHOD • BBM stages: – Reconnaissance, geomorphological survey, and EF sites selection – Biological and social surveys – Hydrological analysis – Hydraulic sections surveys – Specialist workshop where EF are determined • “Building Blocks” include Low and High flows for all 12 months • Driest month and wettest month are analyzed first, interpolation is possible in-between • Flow needs of various components (fish, spiritual needs) are normally expressed as water level, velocity, width etc. • They are converted to discharges using hydraulics and evaluated by hydrology. The largest requirement is accepted as BB.
  21. 21. Zone 1 Gangotri to Rishikesh Zone 3 Narora to Farrukhabad 21 Zone 4 Kannauj to Kanpur
  22. 22. EF SUMMARY, ZONE 1: GANGOTRI- RISHIKESH maintenance flows 14000 12000 10000 8000 6000 4000 2000 0 Site EF1 -Kaudiala EMC A; 72% MAR 1 2 3 4 5 6 7 8 9 10 11 12 Months Flow Volume, MCM maintenance low maintenance high natural total
  23. 23. EF SUMMARY, ZONE 3: NARORA – FARRUKHABAD maintenance flows 14000 12000 10000 8000 6000 4000 2000 0 Site EF3 –Kachla Ghat EMC B, 45% MAR 1 2 3 4 5 6 7 8 9 10 11 12 Months Flow Volume, MCM maintenance low maintenance high natural total Present
  24. 24. PLANNING (GANGES CALCULATOR) AND COMPREHENSIVE (BBM) RESULTS COMPARED EF Site N EF Site Name EMC BBM Workshop result (Total EF as % of natural MAR) Ganges Calculator Result (Total EF as % of natural MAR) 1 Kaudiala A 72 67 2 Kachla Ghat B 45 36 3 Bithoor B 47 35
  25. 25. SUMMARY • EF- is a tool to maintain a river in an agreed condition. EF need to mimic natural flow variability • A combination of simple (planning) and comprehensive (holistic) EF assessment tools is ideal for EF management. The levels of accuracy and confidence differ, but both types of tools have distinct purposes. • A number of EF tools and information, freely available, are already developed for India - for further use and refinement with Indian partners and responsible agencies • Previous studies were normally carried out in the conditions of lack of access to hydrological and hydraulic data. To enhance national EF work, access to these data is imperative. • Actual EF provisions are not the same as estimated EF. No matter how advanced and accurate the estimates are, its output remains on paper if no actual implementation is made. It needs Policy and Institutional support.
  26. 26. THANK YOU !THANK YOU !

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