Water for Nature in the Downstream Areas

DR. BASHIR AHMAD

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

Environmental Flows

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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.

Environmental Flows

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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.

Environmental Flows- Indus System

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The lower riparian views this situation in the context of pre-Kotri 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)

Environmental Flows- Indus System

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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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There has been a significant reduction in the area of mangroves in the Indus Delta over the last 30 yearsMangrove 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

Mangroves of Indus Delta

Sea water intrusionSoil salinity and sodicityEnvironmental pollution Loss of mangrove forest

Reduced supply of fresh waters Untreated wastewater discharge Land clearance

Environmental Issues

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

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Enhanced Catch of Fish using Smaller NetsToxic Industrial Effluent DisposalUrban 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 Coastwide range of pollutants at Orangi Nala and Lyari River watersknown Orangi Pilot Project also disposing all the sewage in to the streams leading to the coast

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Factors Responsible for Degradation of Indus Delta

Below Kotri River Flows

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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 September8 out of 38 years when flows were > 50 MAF9 out of 38 years when flow was < 10 MAF21 out of 38 years when flow was < 1MAF (in rabi season)

Below Kotri River Flows

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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 RabiZero flow days reached 300 in 2 years (2000-01 & 02) River below Kotri remained dry for 200 or more days5 out of 20 (25%) years in pre-Terbela and 9 out of 38 (24%) years in post-Terbela periods

Variability in Below Kotri River Flows

Probability of Excedence (%)

Flow Downstream Kotri Barrage P(MAF)

Pre-Terbela (1956-1975) Post-Terbela (1976-2013)Percent Change

(+/-)Rabi Kharif Annual Rabi Kharif Annual

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

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Extreme variability between highest and lowest flowsHighest flows reduced & lowest further lowered in post Terbela

Drivers of Low Flows Below Kotri

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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%

Period Kharif Rabi Annual Change (%)Pre-Independence 1937-47 44.39 18.49 62.89

Pre-Treaty 1947-60 48.58 23.24 71.82 +8.93 (14%)Pre-Mangla 1960-67 57.11 25.85 82.97 +11.15 (16%)Pre-Tarbela 1967-76 61.68 28.20 89.88 +6.91 (8%)Post Tarbela 1976-2013 63.89 32.97 96.87 +6.99 (8%)Increase from 1937 to 2013 +33.98 (54%)

Flows abstractions of Eastern Rivers by India

Irrigation network development

Drivers of Low Flows Below Kotri

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Declining trend of western river flows: Western rivers flows decreased from 139.7 MAF during (1937-1976) 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 urbanizationExtreme 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

Minimum Environmental Flows

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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. Determine minimum flow below Kotri barrage to control seawater intrusion into the delta

ii. Environmental impacts from river water and sediment flows and their seasonal distribution below Kotri barrage

iii. 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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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”.

Minimum Environmental Flows

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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.

Minimum Environmental Flows

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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.

Minimum Environmental Flows

• 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

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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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Way Forward

THANKS

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