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
Step 1: Use a stakeholder consultation process to set objectives for
the environmental condition of the river
Step 2: Assess a modified flow regime that will meet those
objectives
Step 3: Use flow-dependent indicators (e.g. dolphins, gharial, turtles, fish, invertebrates, floodplain
vegetation), non-consumptive human requirements, as well as water quality metrics and sediment
transport, to identify water depths, velocities, river widths, and substrate types that will provide required
habitats and conditions. Such hydraulic requirements can then be converted to hydrological (flow)
requirements
Step 4: Identify critical components (building blocks) of the flow regime that govern
environmental conditions (e.g. dry and wet season base flows, and different-sized high flows
and floods)
Stage A: Scoping
Task 1:
Stage B: Preparation for the
Assessment
Initiate EFA assessment (level of detail, define methodology)
Task 2: Constitution of the
assessment team
Task 3: Zone the study area
Task 4: Habitat integrity
Task 5: Site Selection
Task 6: Surveys and measurements
Biological Surveys
Hydraulic survey
Hydrological analysis
Task 7: Ecological and Social Importance
and Sensitivity
Task 8: Define reference conditions
Task 9: Define present ecological status
Task 10: Define environmental objectives
Geomorphological survey
Water Quality analysis
Social survey
Stage C: EFA Setting
workshop
Stage E: Implementation and
compliance monitoring
Stage D: Negotiation
Task 1: Hydrological yield analysis
Task 2: Scenario analysis
Task 3: Decision
Objectives
GANGA EFA: Promote the
sustainable use of water resources
in the Ganga to:
- Ensure ecological integrity
-Provide livelihoods
- Maintain sacred values
Flow Indicators
Fish, Dolphins,
Invertebrates, Algae,
Religious rites, Livelihoods,
Channel processes
Habitats
Activities
Processes
Required
Hydraulics
Depth
Velocity
Width
Substrate
7
Hydrology
Cubic metres
per second of
Water required
Rishikesh
•
Zone I: Upper Reach (Gangotri to
Rishikesh)
•
Zone II: Reference zone
(U/S of Garhmukteshwar to Narora)
•
Narora
Zone III: Middle Reach
(Narora to Farrukhabad)
Kannauj
•
Zone IV: Lower Reach (Kannuaj to
Kanpur)
Zone 1
Gangotri to
Rishikesh
Zone 3
Narora to
Farrukhabad
Zone 2 U/S of
Garhmukteshwar
to Narora
(Reference Zone)
Zone 4
Kannauj to
9
Kanpur
Components
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
5.
Evaluate livelihood activities and its implications on environmental flows of the river
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
Arriving at E-Flows
STEP 1: Hydrology and Hydraulics Cross Sections for
each zone
164
ELEVATION
At Kachla Ghat
metres above sea level
163
162
161
160
159
158
0.0
332.1
515.5
587.0
655.5
806.4
Distance from the right bank, m
864.8
1,035.7
1,247.8
STEP 2: Flow motivations
Flow recommendations based on requirements
of biodiversity, Livelihoods, Culture/Spiritual
needs, Geomorphology
Maintenance Flows
The 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 lowflow and high-flow components calculated
Arriving at E-flows
165
At Kachla Ghat
August - maintenance
164
August - drought
metres above sea level
163
162
161
Dry Season-Normal Year
Dry Season-drought
160
159
158
0.0
332.1
515.5
587.0
655.5
806.4
Distance from the right bank, m
864.8
1,035.7
1,247.8
Results: Zone 1, Maintenance Flows
Site -Kaudiyala
14000
E-Flows: 72% of Mean
Annual Runoff
Flow Volume, MCM
Present day flows could
not be calculated, as
flow release data from
the Tehri Dam was not
available
12000
72% MAR
10000
8000
6000
4000
2000
0
1
2
3
4
5
6
7
8
9
10
11
Months
maintenance low
maintenance high
natural total
12
Results-Zone 3: Narora–Farrukhabad Maintenance Flows
14000
Site –Kachla Ghat
Present day flows does
not meet E-Flows
requirement during the
lean season
Flow Volume, MCM
E-Flows requirement:
45% of MAR
45% MAR
12000
10000
8000
6000
4000
2000
0
1
2
3
4
5
6
7
8
9
10
11
12
Months
maintenance low
maintenance high
natural total
Present
Results - Zone 4: Kanauj- Kanpur Maintenance Flows
Site EF4 – Bithur
18000
16000
Present day flows not
meeting E-Flows
requirements for lean
months
14000
Flow Volume, MCM
E-Flows: 47% of MAR
47% MAR
12000
10000
8000
6000
4000
2000
0
1
2
3
4
5
6
7
8
9
10
11
12
Months
maintenance low
maintenance high
natural total
Present
Key Issues
• 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 crosssections, 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
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:
Biodiversity:
Cultural/Spiritual:
Livelihoods:
Geomorphology:
Water Quality:
Hydraulics:
Hydrology:
Prof Jay O’Keeffe, (formerly UNESCO-IHE,
Netherlands) & Dr Vladimir Smakhtin, IWMI
Prof Prakash Nautiyal, Garhwal University
Prof Ravi Chopra, People’s Science Institute
Prof Murali Prasad, IIT Kanpur
Prof Rajiv Sinha, IIT Kanpur
Prof Vinod Tare, IIT Kanpur
Prof A K Gosain, IIT Delhi
Dr Vladimir Smakhtin, Dr Luna Bharati, IWMI
THANK YOU
Building Block Methodology
Different EF Assessment Methodologies
Assessment
Method
Basis
Cost/time
Confidence
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
Holistic
Hydraulics/Ecology
/Geomorph./Social/
Water Quality
High
High
BBM/DRIFT/
Benchmarking
Over 200 methodologies