Source:
Frits Ahlefeldt
The
Prime Minister in a speech some months ago very rightly remarked that “future
generations will not forgive us for the manner in which we have treated our
water”. It would be really nice if this concern was also extended to the plight
of India’s last remaining free-flowing streams and rivers. The dominant
paradigm is that rivers which flow freely all the way to their estuaries and
deltas do not serve any purpose and one often hears politicians and bureaucrats
stating that so much water is going “waste” into the Arabian Sea. The ecosystem
functions, ecosystem services and livelihoods that rivers and streams provide
to communities is rarely mentioned.
No
one doubts that rivers may have be to tapped and hydrology modified for human
use. Many of the gains in agriculture and hydropower generation in India are
from dams, barrages and reservoirs. However it is now time to look at the costs
of further large-scale transformations on the last remaining free-flowing
stretches of rivers and streams and question our entire approach to water
management in the country. The growing evidence from negative impacts of
barrages and dams on downstream ecosystems, ecosystem services and livelihoods
including impacts on productivity of estuaries and deltas should be carefully
assessed by all stakeholders before planning any new transformations.
India is facing
uncertainty and variability from changing climate and so is the competition and
conflict over access to water among sectors and states.
All
over India, from small headwater streams in forested mountains to large rivers,
projects for hydropower generation, abstraction of water for industry, towns
and cities, and even large-scale inter-basin water diversions are ongoing and
planned. Add to that the polluted state of our major rivers, and we can imagine
the magnitude of the problem.
Some
of these projects will, by design, introduce an artificial diurnal cycle into
stream flow with pulses of water released after the power generation cycle that
is a multiple of any natural diurnal fluctuations. The small hydropower
projects (SHP) which are categorised as “green energy” also often result in
diversion of water through pipes and canals, leaving the original stream dry
for up to one km or even a few km. The impacts on native aquatic biodiversity,
riparian ecosystems and some local livelihoods can be substantial. And when
several streams are tapped, the cumulative impact can be irreversible and can
cause extinction of endemic species in the river basin.
The National Water Policy
has mandated that ecological and environmental flows should be maintained in
rivers, but we do not have rigorous scientific guidelines for assessing flow
regimes for specific riverine ecosystems and ecosystem services.
India
is facing uncertainty and variability from changing climate and so is the
competition and conflict over access to water among sectors and states. The
Indian monsoon has been declining since the 1950s, and extreme rain events are
increasing in some parts of the country. The spatial and temporal uncertainty
in the rainfall regime is best illustrated by what we saw in the country this
year: drought in some parts, floods in others and areas with crop failure
subsequently undergoing intense rain and floods. There is broad agreement that
our rainfall regime is changing in complex ways. Furthermore the failure of
climate models to simulate observed trends is worrying, casting doubt on their
future projections.
These
trends need to be considered when large-scale inter-basin transfers are being
implemented or planned. These inter-basin transfers are based on the assumption
that “surplus” water in some basins (in the wet season) can be diverted to
other “deficient” basins. The role of peak monsoonal flows in sustaining
downstream ecosystems and livelihoods, especially the fisheries in deltas,
estuaries and shallow marine ecosystems, is ignored. These ecosystems depend on
sediment, nutrient and freshwater flows to maintain the unique salinity and
biogeochemistry regime that underpins their productivity.
The whole
engineering-dominated discourse on “utilisation” of river waters vis-à-vis
ecological and environmental functions and ecosystem benefits of free-flowing
rivers from headwater to estuaries is being questioned.
In
most cases, water scarcity problems have been addressed by supply augmentation
either through creating additional seasonal storage or diversion from
neighbouring basins.
In
the context of the Western Ghats, numerous inter-basin transfer projects have
been proposed by state and central governments including the National River
Linking Project (NRLP) to divert ‘supposed’ surplus water from the west-flowing
rivers to the scarce basins of east-flowing rivers to meet drinking water,
irrigation and energy demands. However, the notion of ‘surplus’ and its
estimation in a river basin is often based on limited data, flawed
methodologies of environmental flow requirements, non-utilisable river flows
and recurrent floods which discharge into the Arabian Sea. The whole
engineering-dominated discourse on “utilisation” of river waters vis-à-vis
ecological and environmental functions and ecosystem benefits of free-flowing
rivers from headwater to estuaries is being questioned.
Many
scholars now argue that the water surplus assessments conducted as part of NRLP
have ignored a whole range of ecological, environmental and social issues. The
methods used to estimate the environmental flow requirements (EFReq) and in
stream utilisation (water demands) of stream flow to arrive at the surplus
followed the guidelines proposed in the India Water Policy, 2002 and draft
Revised India Water Policy, 2012. These methods applied for estimating EFReq
are scientifically outdated and application of new methods for understanding
environmental flow ‘regimes’ (EFReg) could classify these large storage and
diversion projects either environmentally damaging or socially
unjust/inequitable. Traditional methods of estimating EFReq used either
historical or modelled minimum discharge in the river as essential flows for environmental
benefits, and typically are some percentage of the total annual discharge or
twice/thrice the minimum discharge (measured/modelled) in the stream in an
average year. In India, the concept of impacts of river flow regimes on
specific components of aquatic biodiversity and ecosystem services downstream
is a very recent area of research enquiry and even the concepts and methods are
largely hydrologically and statistically driven rather than comprehensive
approaches encompassing taxa-specific biology, aquatic ecology, ecosystem
services and livelihood dependencies.
We first found out from
our independent measurements that the claim of the authorities that a discharge
of 50 m3/s that was supposedly maintained in the Son downstream of the dam was
not correct. It was a fraction of that!
The
role of flow ‘regimes’ and ‘flow variability’ in maintaining ecologically and
socially beneficial habitat is very recent. For example, tropical estuarine
areas free from major developmental projects have been known for their
extremely productive fisheries. All along the Indian west coast, the estuarine
banks are densely populated with hamlets dependent on fisheries, including
shellfish. There are hardly any rigorous studies to ascertain the importance of
unaltered hydrologic regimes and economic returns from fisheries to in stream
and downstream communities. Even rarer are studies which assess the negative
impacts of altered flow regimes due to hydroelectric projects or diversions in
any of the several rivers from the Western Ghats.
Freshwater,
estuarine and deltaic ecosystems and their biodiversity and ecosystem services
are the most threatened in India due to dams and upstream diversion for
agriculture and industry, overexploitation of groundwater and pollution of surface
water. In addition, growing urbanisation and the need to supply water to
villages and towns is likely to place even greater demands on the limited
supplies of unpolluted water that emerges from forested highlands and wetlands.
The plan to interlink rivers is also raising concerns about impacts on
biodiversity and ecosystem services, apart from its sustainability under the
current climate and future climate change.
The
National Water Policy has mandated that ecological and environmental flows
should be maintained in rivers, but we do not have rigorous scientific
guidelines for assessing flow regimes for specific riverine ecosystems and
ecosystem services. We do not have a management and policy framework that
imposes efficiency on competing water use in industry, cities and agriculture
to enable allocation of water for maintaining ecological and environmental
flows.
Ideally,
multi-stakeholder and inter-disciplinary approaches are needed to estimate
ecological and environmental flows in selected river ecosystems and design an
adaptive management plan that reconciles ecological flows with other competing
uses, and also privileges sustainable use of precious unpolluted water for
drinking water, reduces water use in agriculture, promotes recycling and reuse
by industry and in urban areas. Furthermore this assessment must take into
account ongoing and projected future trends in climate.
Saga
of the Son
There
is legitimate concern about projects on the last remaining free-flowing streams
and rivers, but what about the rivers that are already regulated and managed
(the majority of rivers in most parts of India) in particular ways? Can we
manage them to enhance biodiversity and ecosystem services?
To
illustrate the challenges of maintaining ecological flows, I will cite our
experience from the Son River, a tributary of the Ganga that originates from
the highlands in central India. The Son River had river dolphins, gharial
crocodilians, freshwater turtles, otters and a thriving fishery that sustained
communities of fisher folk.
The
Son was also prized for the quality of its sand. The first major change and
barrier was the Indrapuri barrage in Bihar, completed in 1968, which reduced
the Son to a trickle in the dry season downstream. Dolphins were probably the
first casualty of this barrier and discontinuity of flow. However the Son
upstream of this barrage was still a thriving riverine ecosystem. A 200 km
stretch of the river and part of its two main tributaries, Banas and Gopad, was
declared the Son Gharial Sanctuary in 1981. The Son Gharial Sanctuary is home
to a number of endangered species, with the flagship species being the gharial
(Gavialis gangeticus), narrow-headed softshell turtle (Chitra indica) and
Indian skimmer (Rynchops albicollis). All three species are river specialists
and their breeding ecology and reproductive success are closely linked to the
seasonality of flow regimes and the availability of undisturbed nesting sites
like large, high sand deposits and emergent sandbar habitats.
But
in the last ten years, this 200 km riverine biodiversity hotspot was
transformed. The Bansagar Dam (whose waters are to be shared between MP, UP and
Bihar) was completed in 2006 after decades of planning and construction. As the
gates were shut and the reservoir started filling, the stretch of the Son River
downstream of Bansagar and upstream of Indrapuri was subject to major changes
in flow regime and sediment dynamics. As the reservoir filled up, the river
downstream was choked of dry season flows and sediment. Subsequently once the
reservoir was filled up, a new regime of flows subject to releases of water
from the dam for irrigation and for hydropower generation started. Sand mining
of the exposed riverbed in the dry season proliferated and mining mafias defied
state authorities. Successful gharial nesting was restricted
to only one site along the entire stretch.
High quality water from
ecosystems must be at a premium and industry must not be able to get it cheaply
as has been the case all along.
Meanwhile,
the water of tributaries downstream has been allocated for a series of thermal
power plants, cement factories and townships, one of which has already tapped
the Gopad tributary.
I
was part of a small team consisting of myself, wildlife biologist Ravi Chellam,
and dedicated aquatic ecologists Tarun Nair and Suyash Katdare, who had to
advise the MP authorities on how much water to release from Bansagar Dam to
maintain “ecological flows” in the Son Gharial Sanctuary. Bihar’s share of the
Bansagar water flows through the Son Gharial Sanctuary. We first found out from
our independent measurements that the claim of the authorities that a discharge
of 50 m3/s that was supposedly maintained in the Son downstream of the dam was
not correct. It was a fraction of that! We also discovered that the Gopad and
Banas tributaries were now the lifeline of the Son in the dry season.
Our
basic idea was to try to relate quantitatively release of water from Bansagar
Dam to maintenance of desired water levels at breeding and nesting sites of the
endangered gharial. Using this, we would propose a reservoir
release regime that would be least damaging.
However,
as we worked with a very sincere forest officer and a dedicated team of
ecologists on the ground, we experienced first-hand the complexities of
maintaining ecological flows downstream of reservoirs.
On
20 February 2015, the Bansagar Dam authorities informed that they would release
water from the Bansagar Dam for Bihar state at a discharge rate of 170 m3/s
from 2pm. This raised water levels in the sanctuary by over 50 cm over a couple
of days, an event that would usually not happen at this time of the year,
inundating basking and nesting sites of the gharial.
We
protested and requested them to reduce the rate of discharge, and finally it
was reduced to 125 m3/s after four days. This release regime did connect
isolated pools and gharials were able to move from one site to
another along the river, and even excavated trial nests, but it was a
short-lived connectivity, as the dam gates were shut on 9 March 2015, and no
successful nest emerged in any new site. Such movements can also leave gharials stranded
in less protected sites once the dam gates are shut and water levels recede.
On
6 April 2015, the dam authorities informed us of their plan to release water
again due to demands from UP and Bihar. We requested him to defer any releases
till we discuss the matter with the Forest Department, particularly since
skimmer nesting had commenced on emergent sandbars and islands in the Son
Gharial Sanctuary. Following Forest Department intervention, Bansagar Dam
authorities provided assurances that no water would be released in this period.
They furthered offered to make available, on demand, up to 3 m3/s of water for
maintaining river flow in the sanctuary. However, the sudden opening of a
smaller dam on the Gopad River tributary that caters to the thermal plant
resulted in the drowning of the first clutch of skimmer nests and abandonment
of nesting sites in the one of the important nesting sites in the fourth week
of April 2015. While the increase in water levels was relatively small (< 15
cm), it led to the submergence of a large part of the emergent sandbar that was
used as the skimmer nesting site, and the subsequent disruption of their first
nesting effort.
Finally,
on 8-9 June 2015, the Bansagar Dam authorities were ordered by their superiors
to start releases and this raised water levels by 78 cm, and this release of
water from Bansagar Dam resulted in the total loss of skimmer nests at four
breeding sites. Even mounds created by the sanctuary management, as an
emergency measure, a day earlier could not prevent the inundation of nesting
sites. However the gharials fared better as the 2015 season produced 3 nests in
the only breeding site, and 85-90 hatchlings emerged between late-May and
early-June. But skimmers had a bad year, despite their attempts to nest for a
second time in the same season.
This
is just to illustrate the complexities of managing reservoirs for ecological
flows all over India. In the future, we will have to think of innovative and
creative ways of restoring sediment deposition to riverine ecosystems, which
will be a big challenge.
Conclusion
Ecological
and environmental flow regimes should become an integral part of any future
project design, rather than an afterthought. Ultimately, ecological flows,
water stress and conflicts over competing demands on scarce water resources can
be resolved only by promoting recycling, reducing water use and wastage of
water in all sectors: agriculture, industry and in cities and towns.
Furthermore, high quality water from ecosystems must be at a premium and
industry must not be able to get it cheaply as has been the case all along.
In conclusion, I would
like to dedicate this piece to the memory of Professor Ramaswamy Iyer, former
Union Secretary, Water Resources, Government of India, who passed away on 9
September 2015. He was the architect of the first National Water Policy and
wrote on sustainable water management with insight and foresight. He belonged
to the dwindling tribe of bureaucrat-scholars, and he will be missed by all of
us who are concerned with saving India’s rivers and their ecosystems.
Author : JAGDISH
KRISHNASWAMY
[B Tech,
'89, Civil Eng., H8] Jagdish Krishnaswamy has a B.Tech in Civil Engineering
from Indian Institute of Technology, Mumbai and a MS and Ph.D from Duke
University, North Carolina, U.S.A He is a Senior Fellow and Convener of the
Centre for Biodiversity and Conservation, Ashoka Trust for Research in Ecology
and the Environment (ATREE), Bangalore and Affiliate faculty at the National
Centre for Biological Sciences-TIFR, Bangalore.
