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In this series of columns I have been writing about metaphorical desertification
of governance, ethics, politics, economics, arts and social values.
This week lets talk about down to earth (no pun intended) physical
desertification of the fertile plains of the Indus Basin Irrigation
System. If a holistic and futuristic view is taken of this crisis,
all other problems of the country pale before it.
Let us get through the numbers first. The total cultivated area of
Pakistan is 22.76 million hectares out of which around 80% is irrigated
while the remaining 20% is rain-fed. The irrigated area is mainly
comprised of Indus Basin Irrigation System (IBIS) irrigated by canals
and tube wells. The Indus River and its tributaries, on an average,
bring 154 MAF of water annually. This includes 144.91 MAF from the
three Western rivers and 9.14 MAF from the Eastern rivers. Most of
this, about 104.73 MAF, is diverted for irrigation. 39.4 MAF flows
to the sea and about 9.9 MAF is consumed by the system losses, which
include evaporation, seepage and spills during floods. It is reported
that 5.51 hectare-meter water is required for optimum growth of various
crops while only 2.77 hectare-meter water is available at farm through
fresh water (canal system) resources. There is a shortfall of about
50 percent in irrigation water required for optimum crop needs.
In order to meet that shortfall, the system utilizes over 44 MAF of
groundwater, pumped through more than 500,000 tube wells, in addition
to the canal supplies. In the Punjab, the agricultural heartland,
over 60 percent of irrigation water comes from tubewells. However,
the problem is not simply that of quantity.
National Drainage Strategy (2001-2025) states that about 33 million
tons of salts are annually brought into the IBIS and 18.5 million
tons (56%) of those are leached into the ground water through direct
seepage. Because of this, latest surveys indicate that 36 percent
of ground water is highly saline (over 3000 mg/l or TDS), 15 percent
is marginal (between 1000 and 3000 TDS) and 49 percent is below the
safe limit of 1000 TDS. Most of these ground water sources are located
in the canal commanded areas. Out of the 49 percent ground water that
is nominally fit in terms of total salts, there is problem of sodicity
- sodium carbonates and bicarbonates, measured in Residual Sodium
Carbonate (RSC). A recent survey of Lahore district shows that 70
percent of tubewells have high RSC (over 3). The ultimate situation
is that around 65 to 70 percent of groundwater in the Indus Basin
is either saline or sodic. This is turning the existing situation
even worse by making already degraded soils saltier and subsequently
less productive.
The government's unidirectional approach to the problem is quantitative.
The goals of the government for the development of water resources
are reflected in the WAPDA Vision 2025 document, which stipulates
the addition of 64 MAF of storage capacity and about 27,000 MW of
additional power - mainly through hydel sources, by the year 2025.
The estimated investment for Vision 2025 will be $50 billion spread
over the next 25 years. It does not even begin to understand the qualitative
problem.
In this brief column, I can only provide an overview of the various
dimensions of the water situation in the country.
To begin with, flood irrigation is not a natural way to provide water
to the plants. Over millenniums, plants and soils have evolved under
rainwater. Man invented irrigation to increase production in arid
zones artificially. Over the past century, it has become quite evident
that surface irrigation produces environmental side effects that eventually
become counter-productive. Donor agencies have realized this since
past two decades and will not finance any new dams for surface irrigation.
Simply put, flood irrigation is the most inefficient way to water
crops and produces secondary salinisation.
Indus Basin has practised flood irrigation extensively since past
hundred odd years and salinisation of soils is becoming critical now.
In quantitative terms, at best flood irrigation is 20 to 40 percent
efficient - this much water is used by plants; the rest either leeches
down or evaporates. On this count, Pakistan's water shortage could,
theoretically, be solved by adopting advanced irrigation technologies
like sprinkler, drip or underground by-valve systems that are over
90 percent efficient. Conversion to these methods would reduce salinisation
by 50 percent since less water (with fewer salts) would be going into
the soils. Adoption of advanced irrigation techniques is inconceivable
under present circumstances where agriculture technology has not come
out of the 'Mohenjo Daro' era as yet in the country. It would require
a quantum shift in socio-politico-economic equilibrium of the system
for which neither resources nor vision nor the political will exists.
Inefficient use of water has another implication, besides agricultural
application. Most developed countries allocate at least 40 percent
of available clean water for urban-industrial use. In Pakistan less
than 10 percent is used by non-agricultural sectors. If, by any miracle
Pakistan were to develop in to an industrial, middle income country,
about 30 percent of water will need to be diverted to urban consumption.
Given the current utilisation patterns, agriculture will suffer fatal
cuts in the primary resource of production. It is simply not tenable!
Water pollution from urban-industrial effluents is proliferating in
geometric progressions. Adding to salinisation from ground water and
salts being washed down from the catchment areas of rivers (due to
lack of range management and deforestation), the drainage of toxic
urban refuse-water and industrial chemicals into the rivers and canals
is causing havoc with canal water quality. There are no official figures
available, but I personally know that there are hardly any canals
in middle and lower Punjab where canal water is totally fit for irrigation.
I have measured pH of over 8 (should be between 7 - 7.5) in most canals
with TDS of around 1500 which is marginal. At this rate, it will not
be long before canal water becomes as toxic as water from 70 percent
of tubewells.
As I drove down to Bahawalpur last week, the cotton planted with a
vengeance this year (in anticipation of high prices of last year)
was almost screaming about contaminated soils. In spite of heavy rains
and large doses or urea, growth is stunted with early flowering reaching
up to the top of the plants. The plants are showing signs of latent
hunger as high levels of salts in the soils are blocking uptake of
nutrients.
Economic planners in Islamabad and Lahore would be well advised to
surface from piles of statistical data and have a peek at bio-chemical
forces at work in water sector. Francis Bacon said, "Nature,
to be commanded, must be obeyed." As in other areas of national
policies, the consequences of our defiance in this sector are looming
as a slow desertification of the Indus Basin has already begun.
Iqbal
Mustafa
1140 words
21 August 2004
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