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Environmental Flows Assessment. Objective Based Flow-Setting In certain cases, people intend to have specific pre-defined ecological, economical and social objectives for the river. Scenario Based Flow-Setting - PowerPoint PPT Presentation
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Environmental Flows Assessment
• Objective Based Flow-Setting– In certain cases, people intend to have specific pre-defined ecological,
economical and social objectives for the river.
• Scenario Based Flow-Setting– if water managers are able to understand and make decision on water
allocations and scenarios for trade offs in managing and balancing the water demands/requirements.
Building Block Methodology
• Building Block Methodology – one of the most comprehensive methodology
– Bottom up approach
– Much detailed and can be tailored to suit local conditions
– Most frequently used holistic methodology
– Rigorous and well documented
Building Block Methodology
• Flexible to accommodate other local aspects, like religious and spiritual requirements (hence applicable for Indian rivers)
• Functions well in data-rich and data-poor situations
• Links to external stakeholders and public participation processes
• Applicable to regulated and non-regulated river regimes
• Moderate to highly resource intensive
Building Block Methodology
Stage A: Scoping Stage B: Preparation for theAssessment
Task 1: Initiate EFA assessment (level of detail, define methodology)
Task 8: Define reference conditions
Task 7: Ecological and Social Importance and Sensitivity
Task 9: Define present ecological statusTask 10: Define environmental objectives
Stage C: EFA Setting workshop
Stage E: Implementation and compliance monitoring
Task 2: Constitution of theassessment team
Task 3: Zone the study areaTask 4: Habitat integrityTask 5: Site SelectionTask 6: Surveys and measurementsBiological SurveysHydraulic survey Hydrological analysis
Geomorphological surveyWater Quality analysisSocial survey
Stage D: NegotiationTask 1: Hydrological yield analysisTask 2: Scenario analysisTask 3: Decision
7
RequiredHabitats
ActivitiesProcesses
HydraulicsDepth
VelocityWidth
Substrate
HydrologyCubic metres per second of
Water required
ObjectivesGANGA EFA: Promote the
sustainable use of water resources in the Ganga to:
- Ensure ecological integrity-Provide livelihoods
- Maintain sacred values
Flow IndicatorsFish, Dolphins,
Invertebrates, Algae, Religious rites, Livelihoods,
Channel processes
• Zone I: Upper Reach (Gangotri to Rishikesh)
• Zone II: Reference zone(U/S of Garhmukteshwar to Narora)
• Zone III: Middle Reach(Narora to Farrukhabad)
• Zone IV: Lower Reach (Kannuaj to Kanpur)
Rishikesh
Kannauj
Narora
9
Zone 1 Gangotri to Rishikesh
Zone 3 Narora to
Farrukhabad
Zone 2 U/S of Garhmukteshwar
to Narora(Reference Zone)
Zone 4 Kannauj to
Kanpur
1. Hydrology - Identify and review previous hydrological modeling
studies and assessment of their usability
- To set up model and calibrate under existing conditions of land and water use
- Examine the feasibility of different ways of modeling the past ‘natural’ and present-day flows, using observed flow data
Components
2. Fluvial Geomorphology and hydraulic modeling for maintaining sustainable flows
- Analysis of sediments in the river, and the assessment of the effects that will result from different flow regimes
- Analyse the channel and floodplain morphology in terms of the geomorphic features, and their stability
- Generate the cross section and longitudinal profile for hydraulic modelling
3. Habitat preferences of selected Aquatic species
– Assess present condition in terms of the difference between the reference condition and survey results
– Describe measured depths, average velocities and substratum types most commonly associated with sensitive species and families, and/or with maximum biodiversity
Components
4. Economic and Livelihood objectives for Maintaining Sustainable Flows
- Evaluate livelihood activities and its implications on environmental flows of the river
5. Assessment of Cultural & Spiritual in stream flow required for Maintaining Sustainable Flows
– Representation of the river in mythology, folklore, folk art and popular literature and art
– Historical evidence of civilizations along the river, and its influence on society
– Cultural, Religious, spiritual importance of the Ganga, with focus on rituals and festivals
6. Water Quality and Pollution
– Generation of data on water quality parameters that is not available from any sources, but considered essential by the water quality group (samples from 30 locations)
– Assessment of various types of pollution loads in different stretches/sub-stretches
Components
Arriving at E-FlowsSTEP 1: Hydrology and Hydraulics Cross Sections for
each zone
STEP 2: Flow motivationsFlow recommendations based on requirements of biodiversity, Livelihoods, Culture/Spiritual needs, Geomorphology
Maintenance FlowsThe Maintenance Flows are for "normal" years, not very wet or not very dry, here one would expect all the ecological functions and processes:
fish breeding floodplain wetlands full sediment transport etc.
Maintenance Flows would be equaled or exceeded during 70 years out of 100; however flows would be lower for 30 years out of 100 or in other words, 70% probability on the flow duration curve.
For a long-term E-Flow, the water volume required would be at maintenance recommendations or higher for 70% of the time, and between drought and maintenance for 30% of the time.
STEP 3: Calculating critical flows
Critical flows• Kaudiyala:
– January maintenance flow: fluvial geomorphology
– August maintenance flow: biodiversity• Kachla Ghat & Bithoor:
– August flows (both during maintenance and drought years): cultural and spiritual
• Almost half of the critical flow recommendations were influenced by biodiversity requirements
STEP 4: Calculating annual E-Flows requirements
– Driest and wettest months under maintenance and drought conditions (January – driest month and August – wettest month)
– E-Flows values were calculated, based on inputs from working groups, by hydrologist for other months of the year by means of interpolation
– Monthly flow volumes for each month of the year for low-flow and high-flow components calculated
Arriving at E-flows
Results: Zone 1, Maintenance Flows
0
2000
4000
6000
8000
10000
12000
14000
1 2 3 4 5 6 7 8 9 10 11 12
Months
Flow
Vol
ume,
MCM
maintenance low maintenance high natural total
Site -Kaudiyala
72% MARE-Flows: 72% of Mean Annual Runoff
Present day flows could not be calculated, as flow release data from the Tehri Dam was not available
Results-Zone 3: Narora–Farrukhabad Maintenance Flows
0
2000
4000
6000
8000
10000
12000
14000
1 2 3 4 5 6 7 8 9 10 11 12
Months
Flow
Volum
e, M
CM
maintenance low maintenance high natural total Present
Site –Kachla Ghat 45% MAR
E-Flows requirement: 45% of MAR
Present day flows does not meet E-Flows requirement during the lean season
Results - Zone 4: Kanauj- Kanpur Maintenance Flows
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
1 2 3 4 5 6 7 8 9 10 11 12
Months
Flow
Volum
e, M
CM
maintenance low maintenance high natural total Present
Site EF4 – Bithur
47% MARE-Flows: 47% of MAR
Present day flows not meeting E-Flows requirements for lean months
• Access to observed long term hydrological data, is critical for assessing flows and this would have considerably increased the confidence in the environmental flow assessment.
• Further calibration and verification of the existing rated cross-sections, and the establishment of additional cross-sections, would also increase confidence in the flow recommendations
• Relationships between indicator fish, invertebrates and flow would allow more precise flow recommendations
• More precise relationships between water quality parameters and flow would have allowed the prediction of the effects of recommended flows on water quality to be assessed
Key Issues
E-flows• Not a one time flow; Regime of flows • Assess E-flows using a holistic approach:
hydrology, hydraulics, fluvial geomorphology, water quality, socio-cultural-spiritual, biodiversity and livelihood
• Need to be an integral part of the EIA & CIA – Bottoms up-project, sub-basin to basin level; – Existing projects – Trade-off analysis
• Need to place it in the context of river basin management plan
E-flows• Implementation & monitoring
– Joint monitoring– Whether required releases are being made– Impacts
• Adaptive process needed in E-flows assessment and implementation
• The EF process should be embedded in a framework of inclusive stakeholder understanding and participation, and preferably within a broader context of IWRM
Partners
Facilitation: Prof Jay O’Keeffe, (formerly UNESCO-IHE, Netherlands) & Dr Vladimir Smakhtin, IWMI Biodiversity: Prof Prakash Nautiyal, Garhwal UniversityCultural/Spiritual: Prof Ravi Chopra, People’s Science InstituteLivelihoods: Prof Murali Prasad, IIT KanpurGeomorphology: Prof Rajiv Sinha, IIT KanpurWater Quality: Prof Vinod Tare, IIT KanpurHydraulics: Prof A K Gosain, IIT DelhiHydrology: Dr Vladimir Smakhtin, Dr Luna Bharati, IWMI
THANK YOU
Building Block Methodology
Assessment Method
Basis Cost/time Conf-idence
Example
Look-up tables Hydrology Small Low Tennant
Time Series models Hydrology Small/Medium Low IHA
Rated X-Section models
Hydraulics Medium Medium Intermediate (SA)
Habitat Models Hydraulics/Ecology High Medium IFIM
Regional Hydrology/Ecology High (initial) Medium ELOHA/Desktop
HolisticHydraulics/Ecology/Geomorph./Social/
Water QualityHigh High BBM/DRIFT/
Benchmarking
Different EF Assessment Methodologies
Desktop (Half-Day)
Over 200 methodologies