6. Water for Nature in the Downstream Areas

Report
Water for Nature in the
Downstream Areas
DR. BASHIR AHMAD
Environmental Flows
Environmental Flows refer to water provided
within a river or wetland to maintain ecosystem
services and benefits they provide.
Environmental Flows describes the quantity,
quality and timing of water flows required to
sustain ecosystems and the human livelihoods
and well-being that depend on these ecosystems
2
Environmental Flows
Environmental flows are effectively a balance
between water resources development and
the need to protect freshwater-dependent
ecosystems.
Other definitions and terms regarding
environmental flows do exist. These include
minimum, in stream and ecological flow.
3
Environmental Flows- Indus System
In average year 74% of the Indus River flows are abstracted for
irrigation and it reaches to 88% in the dry years and reduces to
50% in the wet years.
As a result of upstream water abstractions, mainly for
irrigation, by the time the Indus reaches the Kotri barrage,
there is inadequate flow to maintain the natural ecosystems of
the Indus delta in the dry years and too much water in the wet
years.
Freshwater Below Kotri reaching the delta was argued by the
lower riparian to be insufficient to maintain healthy natural
ecosystems, and had resulted in saltwater intrusion and
salinization.
4
Environmental Flows- Indus System
The lower riparian views this situation in the context of preKotri and pre-Tarbela periods, which is now a history, as
Tarbela dam was constructed 38 years ago.
Now the flows below Kotri in the post-Tarbela context need to
be assessed.
The serious concern is in those years when the flows below
Kotri are less than 3.6 MAF as proposed by International Panel
of Experts (IPOE)
5
Indus Delta Ecosystem
Built up by the discharge of large
quantities of silt washed down from
upland and mountain areas
Stretched over an area of about
41,440 km². The active part of the delta
is 6,000 km² in area.
It is characterized by 17 major creeks
and innumerable minor creeks, mud flats
and fringing mangroves
Mangroves resource – 6th largest in the
world
Home to many birds, fish and Indus
Dolphin
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Mangroves of Indus Delta
There has been a significant reduction in
the area of mangroves in the Indus Delta
over the last 30 years
Mangrove coverage
 0.4 mha in 1965
 0.263mha in 1977
 0.158 mha in 2001
Mangroves Pockets
 Miani Hor: 7,471 ha
 Kalmat Khor: 10,216 ha
 Gawatar Bay: 26,316 ha
Environmental Issues
Sea water intrusion
Soil salinity and sodicity
Environmental pollution
Loss of mangrove forest



Reduced supply of fresh waters
Untreated wastewater discharge
Land clearance
Factors Responsible for
Degradation of Indus Delta
Decline in Below-Kotri Fresh River Flows
• Pre Tarbela: 58.5 MAF (50%
probability)
• Post Tarbela: 26.9 MAF (50%
probability)
Indiscriminate Mangroves Cutting
• Factor are fuel wood, timber mafia,
encroachment, land mafia,
urbanization, over gazing, effluents
and meandering creeks
9
Factors Responsible for
Degradation of Indus Delta
Enhanced Catch of Fish using Smaller Nets
Toxic Industrial Effluent Disposal
Urban Pollutants Disposal
450 to 472 million gallons per day of
sewage is generated in Karachi
Karachi Water and Sewerage Board are
treating about 30% of wastewater and
sewage; rest goes into sea without any
treatment
BOD and COD is a Major Concern at Coast
wide range of pollutants at Orangi Nala
and Lyari River waters
known Orangi Pilot Project also
disposing all the sewage in to the
streams leading to the coast
10
Below Kotri River Flows
Pre Tarbela: 58.5 MAF (50% probability)
Post Tarbela: 26.9 MAF (50% probability)
Affected by extreme variability of Indus river
flows, highest 91.8 MAF, lowest 0.3 MAF and
average of 26.9 MAF (1976-13)
Downstream flows are highly erratic as most
of the flows are released during water surplus
monsoon period of three months from July to
September
8 out of 38 years when flows were > 50 MAF
9 out of 38 years when flow was < 10 MAF
21 out of 38 years when flow was < 1MAF (in
rabi season)
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Below Kotri River Flows
frequency of zero flow days in the Rabi season has a direct
impact on the downstream system
Zero flow days occurred in 28 years (73%) in kharif and 38
years (100%) in the Rabi
Highest zero flow day 180 in Rabi
Zero flow days reached 300 in 2 years (2000-01 & 02)
River below Kotri remained dry for 200 or more days
5 out of 20 (25%) years in pre-Terbela and 9 out of 38 (24%)
years in post-Terbela periods
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Variability in Below Kotri
River Flows
Flow Downstream Kotri Barrage P(MAF)
Pre-Terbela (1956-1975)
Post-Terbela (1976-2013)
Rabi
Kharif
Annual
Rabi
Kharif
Annual
Percent
Change
(+/-)
Maximum
0.0
8.1
8.1
0.0
0.2
0.3
-96.3
90
0.0
21.0
21.2
0.0
2.1
2.1
-90.1
75
0.4
30.3
35.9
0.1
10.9
11.0
-69.4
50
2.9
57.0
58.5
0.7
26.7
26.9
-54.0
25
8.4
73.1
91.1
2.6
43.8
45.4
-50.2
10
18.1
10.7.0
121.0
5.0
64.1
69.1
-42.9
Minimum
20.7
108.1
128.8
12.3
88.2
91.8
-28.7
Probability of
Excedence (%)
Extreme variability between highest and lowest flows
Highest flows reduced & lowest further lowered in post Terbela
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Drivers of Low Flows Below Kotri
Flows abstractions of Eastern Rivers by India
Periods
Kharif
Rabi
Annual
Change (%)
Pre-IWT (1937-60)
19.80
4.13
23.94
Pre-Terbela (1961-75)
13.42
2.17
15.59
-35%
Post-Terbela (1976-2013)
5.19
1.43
6.70
-57%
Irrigation network development
Period
Pre-Independence 1937-47
Kharif
44.39
Rabi
18.49
Annual
62.89
Change (%)
Pre-Treaty 1947-60
Pre-Mangla 1960-67
Pre-Tarbela 1967-76
Post Tarbela 1976-2013
Increase from 1937 to 2013
48.58
57.11
61.68
63.89
23.24
25.85
28.20
32.97
71.82
82.97
89.88
96.87
+8.93 (14%)
+11.15 (16%)
+6.91 (8%)
+6.99 (8%)
+33.98 (54%)
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Drivers of Low Flows Below Kotri
Declining trend of western river flows:
Western rivers flows decreased from 139.7 MAF during (19371976) to 128.2 MAF during (1976-2013) period (8.23 % decrease).
Domestic and industrial demands
• 2.5 MAF/year in the early 1975s (FAO STAT)
• 12.38 MAF/year in 2007-08 (400 % increase)
• 17 MAF/year by 2025 due to rampant population growth,
industrialization and urbanization
Extreme events
• Pakistan experienced extreme events recently floods in 2010, 2011 and
2012 and severe drought of 1999-2003 which had severe impacts on
Indus delta.
• Predictions are that these sorts of extreme events are likely to be
repeated more frequently and cause even more severe problems.
• By the end of the century, temperature in the deltaic region could
increase by 40C
15
Minimum Environmental Flows
Water Apportionment Accord established water entitlements, expected
future storage (10 MAF) and need for flow below kotri.
Different opinions on minimum escapage below kotri (10 MAF as interim
outflow).
Three studies were agreed and commissioned to reach consensus on the
minimum required escapages below Kotri barrage:
i.
ii.
iii.
Determine minimum flow below Kotri barrage to control seawater
intrusion into the delta
Environmental impacts from river water and sediment flows and
their seasonal distribution below Kotri barrage
Environmental concerns about a wide range of issues related to the
management of water resources upstream of Kotri barrage
These reports were then assessed by an International Panel of Experts
(IPOE)
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Minimum Environmental Flows
IPOE Recommendation
An escapage at Kotri barrage of 5,000 cubic feet per second throughout the
year (3.6 MAF) to check seawater intrusion, accommodate the needs for
fisheries and environmental sustainability, and to maintain the river channel.
It is recommended that a total volume of 25 MAF in any five-year period be
released in a concentrated way as flood flow (Kharif period) to maintain
sediment supply to the mangroves and coastal zone”.
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Minimum Environmental Flows
The accord did not specify how these environmental flows would be
accommodated within the allocations
Would they come “off the top” thus reducing allocations to all provinces) or
come out of the allocations to Sindh the province in which the delta is
located?
IRSA has been including environmental flows from “off the top” while
calculating the allocations for the provinces.
The accord also did not assign responsibility for delivering and monitoring
these flows.
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Minimum Environmental Flows
The recommendations of the Panel study, however, could not be
materialized, so far due to unknown reasons. Increasing zero flow days
indicate that Panel recommendation of 5000 cfs per day is not being
exercised
In the absence of implementation of the Panel’s recommendation which
is based on detailed studies and analysis of reputed international
experts as per decision of the Accord, controversy of minimum
environmental flows persists.
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Way Forward
• International Panel of Experts recommendation must be
enforced in true letter and sprit
• Some viable, transparent system for flow measurement must
be enforced
• Study to assess the damage already done to mangroves,
fisheries, livestock and other manifestations of bio-diversity
in the Indus delta
• Ensure effective enforcement of National Environmental
Quality Standards for municipal and industrial effluents
20
Way Forward
• Develop a reliable system of data
collection, storage and sharing
• Also initiate studies for ecosystem
characterization and their valuation
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THANKS
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