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Pakistan
Irrigation
In the early 1990s, irrigation from the Indus River and its tributaries
constituted the world's largest contiguous irrigation system,
capable of watering over 16 million hectares. The system includes
three major storage reservoirs and numerous barrages, headworks,
canals, and distribution channels. The total length of the canal
system exceeds 58,000 kilometers; there are an additional 1.6
million kilometers of farm and field ditches.
Partition placed portions of the Indus River and its tributaries
under India's control, leading to prolonged disputes between India
and Pakistan over the use of Indus waters. After nine years of
negotiations and technical studies, the issue was resolved by
the Indus Waters Treaty of 1960. After a ten-year transitional
period, the treaty awarded India use of the waters of the main
eastern tributaries in its territory--the Ravi, Beas, and Sutlej
rivers. Pakistan received use of the waters of the Indus River
and its western tributaries, the Jhelum and Chenab rivers.
After the treaty was signed, Pakistan began an extensive and
rapid irrigation construction program, partly financed by the
Indus Basin Development Fund of US$800 million contributed by
various nations, including the United States, and administered
by the World Bank. Several immense link canals were built to transfer
water from western rivers to eastern Punjab to replace flows in
eastern tributaries that India began to divert in accordance with
the terms of the treaty. The Mangla Dam, on the Jhelum River,
was completed in 1967. The dam provided the first significant
water storage for the Indus irrigation system. The dam also contributes
to flood control, to regulation of flows for some of the link
canals, and to the country's energy supply. At the same time,
additional construction was undertaken on barrages and canals.
A second phase of irrigation expansion began in 1968, when a
US$1.2 billion fund, also administered by the World Bank, was
established. The key to this phase was the Tarbela Dam on the
Indus River, which is the world's largest earth-filled dam. The
dam, completed in the 1970s, reduced the destruction of periodic
floods and in 1994 was a major hydroelectric generating source.
Most important for agriculture, the dam increases water availability,
particularly during low water, which usually comes at critical
growing periods.
Despite massive expansion in the irrigation system, many problems
remain. The Indus irrigation system was designed to fit the availability
of water in the rivers, to supply the largest area with minimum
water needs, and to achieve these objectives at low operating
costs with limited technical staff. This system design has resulted
in low yields and low cropping intensity in the Indus River plain,
averaging about one crop a year, whereas the climate and soils
could reasonably permit an average of almost 1.5 crops a year
if a more sophisticated irrigation network were in place. The
urgent need in the 1960s and 1970s to increase crop production
for domestic and export markets led to water flows well above
designed capacities. Completion of the Mangla and Tarbela reservoirs,
as well as improvements in other parts of the system, made larger
water flows possible. In addition, the government began installing
public tube wells that usually discharge into upper levels of
the system to add to the available water. The higher water flows
in parts of the system considerably exceed design capacities,
creating stresses and risks of breaches. Nonetheless, many farmers,
particularly those with smallholdings and those toward the end
of watercourses, suffer because the supply of water is unreliable.
The irrigation system represents a significant engineering achievement
and provides water to the fields that account for 90 percent of
agricultural production. Nonetheless, serious problems in the
design of the irrigation system prevent achieving the highest
potential agricultural output.
Water management is based largely on objectives and operational
procedures dating back many decades and is often inflexible and
unresponsive to current needs for greater water use efficiency
and high crop yields. Charges for water use do not meet operational
and maintenance costs, even though rates more than doubled in
the 1970s and were again increased in the 1980s. Partly because
of its low cost, water is often wasted by farmers.
Good water management is not practiced by government officials,
who often assume that investments in physical aspects of the system
will automatically yield higher crop production. Government management
of the system does not extend beyond the main distribution channels.
After passing through these channels, water is directed onto the
fields of individual farmers whose water rights are based on long-established
social and legal codes. Groups of farmers voluntarily manage the
watercourses between main distribution channels and their fields.
In effect, the efficiency and effectiveness of water management
relies on the way farmers use the system.
The exact amounts of water wasted have not been determined, but
studies suggest that losses are considerable and perhaps amount
to one-half of the water entering the system. Part of the waste
results from seepages in the delivery system. Even greater amounts
are probably lost because farmers use water whenever their turn
comes even if the water application is detrimental to their crops.
The attitude among almost all farmers is that they should use
water when available because it may not be available at the next
scheduled turn. Moreover, farmers have little understanding of
the most productive applications of water during crop-growing
cycles because of the lack of research and extension services.
As a result, improvements in the irrigation system have not raised
yields and output as expected. Some experts believe that drastic
changes are needed in government policies and the legal and institutional
framework of water management if water use is to improve and that
effective changes can result in very large gains in agricultural
output.
Data as of April 1994
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