AGRICULTURE AND
WATER RESOURCE DEVELOPMENT IN NORTHER
SRI LANKA
INDRODUCTION
The purpose of this
study is to focus attention on issued related to water resource development for
agricultural purposes in the Northern region. As this is a war torn area there
is instability both about settlement and agricultural activities. But we wish
to draw attention to other long term measures related to reconstruction and
redevelopment in Northern Sri Lanka, once peace is restored. Firstly we deal
with the agricultural system and then move on the surface water resource
development in Vanni. After this we deal with development to of underground
water resource in the Jaffna peninsula. Finally we put forward some concrete
suggestions for water resource development in relation to agriculture.
Agriculture is the main
occupation of the inhabitants of the North, part of the traditional homeland of
the Tamil people; sixty per cent of the people are engaged in agricultural
activities, I confine myself here to the northern region. Generally the farmers
followed traditional methods of cultivation but in recent times new
agricultural technology has attracted plenty of farmers and consequently
changes are evident in agricultural inputs, irrigation and water management.
Agricultural activities
in the North largely depend on the rainfall. The average annual rainfall in the
north, which is part of the Dry Zone, is 1250mm or 55 inches. There are
regional variations in the pattern of rainfall but it can safely by said that
the traditional homeland of the Tamils, which includes the East, receives
between 50-75 inches of rain annually. This region receives the bulk of the
rainfall between October to January during the North-East monsoon. Seventy
percent of the rain in this region falls during these four mouths. 20 to 25
percent of this rainfall drains off to the sea; 40-45 percent evaporates.
According to some estimates, only the balance is available for agricultural
purpose. It is only by conserving this sole water resource as surface water and
as underground water that agriculture can be developed in this region.
WATER RESOURCE
IN THE VANNI REGION AND THE DEVELOPMENT OF IRRIGATION FACILITIES
The water resources
available in the north can be classified into two main categories; 1) Surface
water resource and 2) Underground water resources. Surface water is the main
resource in the mainland, excluding the Jaffna Peninsula, (Vanni region). In
the Jaffna Peninsula, underground water resources are the main source of
irrigation.
When one talks of
surface water resources, one is referring to rivers and tanks. In the North
East province, with the exception of the Mahaweli Ganga all the other rivers
have their source in the Dry Zone. The monsoonal rains fill the rivers and the
tanks. The waters of these rivers and their tributaries are dammed in their
catchment areas enabling tanks to be filled with water. Some rivers have been
diverted. This system of irrigation had been prevalent in the Tamil regions
even before the Christian era, as the Pali chronicle Mahavamsa rectifies.
According to the Mahavamsa, Kuveni had met Vijaya when she was sitting on a dam
and weaving. That tank was situated in Mannar (Manthai) according to the
description given in the Mahavamsa.
The tanks located in
the Vanni region (mainland of the Northern Province) can be classified into
three types;
1) Small tanks (these are less than 200
acres in extent) II) Intermediate tanks (those between 200 to 1500 acres in
extent) and III) Major tanks (over 1500 across in extent). The maintenance of small tanks (or minor
irrigation works, as they are sometimes called) is the responsibility of the
Department of Agrarian Services of the respective region. The other two types
of tanks are the direct responsibility of the Irrigation departments. This
Department which was set up in 1900 has drawn up and implemented several
irrigation schemes to foster the agricultural development of the country. In
1959 the Irrigation Department published a map, with comments on the inherent
irrigation potentialities. In this map, out of the 103 possible catchment areas
in Sri Lanka 61 are located in the North and East.
The irrigation
Department has published a map showing the annual discharge of waters for one
square mile. According to this map, a line has been drawn between Vavuniya and
Elephantpass and the map indicates that on the Western side of the line, it has
an up-per capacity of holding 500-acre
feet. This shows that there is greater irrigation potentiality on the eastern
side of the line. Through further research we can estimate how much water can
ge conserved for irrigation purposes.
Generally the Vanni
region possesses water resource potentialities to a large extent. Reservoirs
have been built in the catchment areas of only some of these sites. Apart from
the small and intermediate tanks which can be redeveloped, there are 10 major tanks
in the Northern province. Some of the major tanks can be further expanded; many
of them can be linked with one another so that their capacity to hold water can
be increased. This linkage can take the form of connecting one catchment area
with another. As the surface area of this region is largely low-lying and has a
wave shape there is good scope for development.
The major portion of
the Vanni region that covers the traditional homeland offers great potential
for agricultural development in the future. There are two ways in which
agricultural development can be expanded;
1) Increasing the yields of fields
already under cultivation.
2) Bringing new lands under the plough.
To increase the yields of fields already under cultivation, modern techniques
of cultivation introduces by the green revolution can be profitably propagated
among farmers. For these modern agricultural methods to be successful, fields
under cultivation should be covered by irrigation schemes. For new high yields
varieties of seed paddy, to be cultivated scientifically, it is imperative that
the paddy fields are assured of irrigation facilities. Another way on
increasing the yield is to see to it that paddy is cultivated annually during
two or three seasons; this is feasible if irrigation facilities are enhances
several people have successfully cultivated paddy thrice a year (the Maha
season, the Yala season and Intermediate season).
With the exception of
the Jaffna Peninsula, the mainland offers a lot of scope for bringing new
fields under the plough, Bearing in mind that 25 percent of a country’s land
surface should be reserved for forests, new agricultural settlements can be
opened up in a scientific manner in areas where new fields are to be brought
under the plough. It is also possible to expand already existing agricultural
settlement.
It is imperative to
develop irrigation facilities in a planed manner. One o the ways in which this
could be done is increasing the capacity of tanks which have already been
developed, another is linking up the small, medium and large tanks in the
catchment areas of the region; yet another way is diverting the catchment area
wherever feasible. In this manner irrigation facilities can be enhanced so that
more lands can be utilized for agricultural purposes. Moreover only some of the
catchment area (numbering 22 in all) have been to the maximum; several of these
catchment areas have a lot of potential. For instance, Parangiaru, which has
its source in Vavuniya and flows into Illupaikadavai in Mannar has not been
systematically tapped so far for irrigation purposes. Irrigation experts are of
the view that a major reservoir like Iranaimadhu can be constructed can be at
this site. Similarly, it has been said that another reservoir can be
constructed at Paliaru which falls under the Vavuikulam scheme. Hence one sees
that major irrigation schemes can be successfully launched in the Vanni region
to boost agricultural production.
UNDERGROUND WATER RESOURCE IN THE
JAFFNA PENINSULA AND THE DEVELOPMENT OF IRRIGATION FACILITIES
From historic times,
the underground water resources in the Jaffna Peninsula have been the
foundation for human settlement. Seventy percent of the population of the
Northern Province resides in the Jaffna Peninsula, the peninsula’s underground
water resources account both for the density of the population and intensive
cultivation.
If a line is drawn from
Puttalam linking Paranthan and Mullaitivu, the areas lying towards the north
west of this line have a limestone rock formation dating to the Miocene Age.
These rock formations have the capacity to conserve large amount of water
underground. Redsoil has the quality of allowing water to percolate downwards.
Rainwater easily sees through and is conserved as underground water. Actually
the water that seeps down is a layer of potable water floating on saline water.
As one goes from the coastal area of the Peninsula towards the centre, this
layer thickens the maximum thickness ranges from 100-110. This layer of potable
water has been fragmented by the salt-water lagoons I the middle of the
Peninsula. If these salt water lagoon can be converted into a fresh water
lagoon then the layers of potable waters will merge and form a large layer of
good water, thus enhancing the underground water resources several fold.
Limestone rock
formation are found at a very deep level in the mainland an in the Jaffna
Peninsula at not such a deep level. Therefore in the Jaffa Peninsula deep wells
do not have to be dug to obtain good, drinking water. On the other hand, in
the, mainland areas lying south of the line linking Puttalam, Paranthan and
Mullaitivu the limestone rock formation lies very deep underground.
Consequently tube wells have to be sunk at great expense to tap the underground
water for irrigation purposes. For example in the Kilinochchi district 40
percent of the land area has a layer of limestone rock formation. The balance
60 per cent is comprised of Pleistocene Alluvial soil. The underground water
obtained here is free of salinity. Hence even if it is costly, through the sinking
of tube wells, a considerable extent of land can be irrigated, In mannar
District, except for 20 per cent of the land area, the balance has underground
water resources. In this district6 up to now more than 125 tube wells have been
successfully sunk. In the Mullaitivu District underground water resources are
available at a very deep level. Tapping this underground water resource will be
very expensive.
Human settlement in
Jaffna predate the dawn of the Christian era. From that time onwards, people
have sunk wells to tap the underground water resources for drinking purposes
and for agricultural purposes. Plenty of evidence testifies to this. The
underground water has been drawn up through well sweeps and locally improvised
machines for irrigation purposes. In the course of time, with the cultivation
of subsidiary food crops the water pump has
come to be increasingly uses in Jaffna. Even in the villages, the use of
the water pump has increased. This has led to problems in recent times in many
areas of the Jaffna Peninsula; the underground water is turning saline. This is
a very grave threat; to meett this threat successfully, intensive research has
to be management, and the possibilities of developing these resources. In 1965,
the Water Resource Board carried out some research on the underground water
resources available in Jaffna and the possibilities of sinking tube wells for
irrigation purposes but up to date the reports have not been formally
published. More than ever before today we are forced to think seriously about
the problems caused by the depletion of Jaffna’s underground water resources
and ways and means of solving these problems. There is also a necessity to
undertake development in a planned manner.
DEVELOPMENT
PROPOSALS
We put forward here
certain development proposals for consideration. The proposals fall under two
main heads;
a) the development of the Jaffna
Peninsula’s underground water resources and
b) the development of the mainland’s
surface water resources and its underground
water resources
It is a mistake to
think that the land under cultivation in the Peninsula can be further
increased. This can only lead to disaster consequence. The only course is to
modernize existing agricultural practices and the use and management of water
resources. The waste of valuable water resources should be avoided at all
costs; agricultural practices should be modernized so as to yield maximum
returns. Hereafter agricultural extension activities should concentrate on the
main land. Since the density of the main land population is low, people should
be given incentives to encourage them to settle in the main land. To attract
the population to settle in the fertile areas of the mainland, several
development schemes should be launched.
The efficiency of land
utilization in the Jaffna Peninsula should be maximized. Cultivation in the
peninsula is carried out at great expense, therefore every inch of land must be
made to yield the maximum. Agricultural development should be viewed as agro business.
Instead of cultivating paddy in the Peninsula, farmers should be encouraged to
concentrate on cash crops and the cultivation on subsidiary food crops,
vegetables, fruits etc. This production could serve as the basis for the
development of agro industries by supplying the raw materials. Tobacco
cultivation should be encouraged because tobacco cultivation doesn’t need large
extents of land or much use of water. Tobacco cultivation is not only
profitable but also helps the expansion of agro industries. Like tea and
rubber, tobacco too can earn foreign exchange for the country. Cultivation in
village close to towns should be geared to the urban markets. Jaffna’s
cultivation should take into account the needs of the market.
Experts are of the
opinion that steps should be taken to replenish Jaffna’s underground water
resources. The only replenishment available is the meager rainfall during the
north east monsoon period. Special care should be taken to ensure that the
rainwater doesn’t drain off into the sea but is conserved to augment the
underground water resources of the Peninsula. There are 1050 pounds in Jaffna.
The built of the water that fills these ponds seeps downwards and replenishes
the underground water resources. Some of these ponds are drying up due to
sitting and dumping of garbage so that their capacity to let the water seep
underground in curtailed. An urgent task is to delist these ponds which
function as a replenishment for Jaffna’s underground water resources. The
organization named Ootru took some constructive measures in this regard a few
years ago. These tasks should be carried out in the village.
There is a practice
here of allowing the soil from the ponds to be taken away for use in garden
farms. Great caution should be exercised in this regard. Ponds should not be
deepened to the extent where their underground water table is exposed. If that
is allowed to happen, underground water will evaporate; therefore, permission
should be given to remove soil only up to a certain depth.
In the certain areas of
the Jaffna Peninsula, the top portion of the caverns through which underground
water flows is I a state of collapse.
In a study undertaken
of the Puttur tidal well, it was found that 30,000 to 40,000 gallons of water
could be pumped out in ten hours to irrigate garden farms. Such wells (which
are also found in Kurmabasiddy, Punnalaikadduwn, Alvai and Karaveddy) can be
used not only for irrigation purpose but also for augmenting Jaffna’s
underground water resources during the rainy season, in a systematic manner.
Underground water also
flows into the sea through the underground caverns. An example is the water
that comes through the kerni at keerimala. The caverns, which allow underground
water to flow into the sea, should be identified and underground dams built to
prevent this recurring. Such proposals have been put forward earlier but
unfortunately not implement.
Anyone who has thought
about Jaffna and its planned development for the future could not but come to
the conclusion that the lagoons have to be converted into fresh water lagoons.
Through such conversion (desalination) not only will Jaffna’s underground water
resources be augmented but also the rain water that drains off into the sea can
be a source of replenishment, after desalinization, for Jaffna underground
water resources.
As the result,
underground water resources will not be fragmented in pockets but will form a
continuous layer. Consequently, the salinisation of fresh water will become
less of a problem that it in now and barren lands will become fertile. The
extent of land that can be brought under the plough in the Peninsula will
increase and so will the fresh water resources. Desalinisation of the lagoons
will bring as all these benefits. This idea of converting the salt lagoons into
fresh water lagoons was put forward nearly a century ago. In 1922 when the dam
of the Iranaimadu tank was being constructed the idea was mooted of turning the
Elephant Pass lagoon into a fresh water one.
There are 13 lagoons
that can be converted into fresh water ones and 33 dams to prevent salt water
coming in. Planning for the long term, out of these 13 lagoons, the following
four lagoons can be desalinized, without much expenditure- (1) The Elephant
Pass west lagoon (2) The Elephant Pass east lagoon (3) Thondainanar lagoon and
(4) Upparu lagoon. Several plans were formulated to desalinize the above
lagoons and parts of these plans have been implemented. As fisher folk believe
that salt water is conducive to the catching of fish, they allow salt water to
come in; as a result these plans have not been fully successful. It is
necessary that the plans be fully implemented. Moreover, some of the other
lagoons surrounding the Peninsula can be converted into fresh water ones,
without much expense, For example, the lagoon that separates Velanai and
Mandaitivu can be easily converted into a frsh water lagoon. By closing the
Pannai and Araly causeways, a large fresh water lagoon can be formed south west
of Jaffna Town.
Through the
implementation of such schemes, not only can the supplies of fresh water be
augmented but also salinity can be eliminated, thus making hitherto barren
lands fertile one. This will be a blessing for Jaffna starves as it is of
arable land and a shortage of fresh water.
Those who oppose the
conversion of salt-water lagoons into fresh water ones put forward two main
objections.
The first objection
they put forward is that if the entry of water into the lagoons is blocked,
during the dry spell, the lagoon will completely dry up and the strong blowing
will create dust storms, thereby polluting the residential environment.
This threat can be
easily overcome conserving fresh water in such a manner that there is no
complete drying up and by identifying
the areas which are prone to drying up completely and growing grass in these
areas in a systematic manner. The example of the Netherlands is instructive
here. There, the lagoons have been reclaimed grass systematically cultivated
and animal husbandry encouraged.
The second main objection
is that the livelihood of people who fish in the salt-water lagoon will be
adversely effected. The answer to this objection that groups of people who will
be adversely affected should be identified and they should be relocated in
suitable coastal area. They should be encouraged to take to deep sea fishing
instead of fishing in the shallow lagoon. This will also benefit them
economically. Fisher folk who are likely to be affected should be relocated
either in the Peninsula or in the Eastern coast of the mainland and encouraged
to pursue deep-sea fishing. This might cause difficulties in the short run but
in the development of the region in the long term will be highly beneficial.
It is true water
management is not what it should be either in the Peninsula or the mainland. We
can consider water management under two heads, (1) the management of reservoirs
and the release of water from these reservoirs. (2) water management at field
level.
As far as the first is
concerned, the responsibility for water management lies largely with the State.
Where field level water management is concerned, it depends largely on the
educational level of the farmer, their participation and co-operation.
Generally it can be said that water management has not kept pace with the development
of water resources. After the introduction of the water pump. It is felt that
in Jaffna excessive draw off of water is taking place to irrigate the crops.
This is one factor in the increase of salinisation. Farmers in a particular
region should be educated about what crop should be used and how much water
should be used to irrigate it during a particular season. Such education of
farmers is necessary in view of the fact that the prevalent system of
irrigation accelerates evaporation. To prevent this the system of sprinkler irrigation and
other modern techniques used in Israel should be adopted.
Planning for the
development of water resources calls for the systematic collection of data.
This calls for co-operation among experts of several different disciplines,
thus it is essentially an inter disciplinary task involving expertise in varied
fields ranging from Geography to Agriculture. This inter disciplinary task
force should work together as a team to ensure success.
As far as the mainland
is concerned, not enough work has been done to estimate the available water
resources. In the forests of the Vanni, there are several old tanks, which have
silted up. Desilting has to be carried out in such cases. The capacity of tanks
presently operational should be increased as was done in 1980/81 in the case of
some tanks. New reservoirs too should be constructed by damming the catchment
areas of Parangiaru and Paliaru.
By enhancing the lift
irrigation facilities of certain selected tanks in the mainland, the
cultivation of subsidiary food crops could be encouraged. In the agricultural
settlements in the North, it is noteworthy that the most successful where the
educated youth settlement which were provided with left irrigation facilities
for the cultivation of subsidiary food crops.
In conclusion, it has
to be said that the planned development both of agriculture and of water
resources in the North will be fully successfully only if they are the outcome
of decisions taken by the people of the region. Only if administrative control
is in the hands of the people, that we can attain only self-sufficiency but
also produce a surplus.
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