Abstract
Groundwater is playing an essential role in expanding irrigated
agriculture in many parts of the world. Pakistan is the third-largest user of
groundwater for irrigation in the world. The surface water supplies are
sufficient to irrigate 27% of the area, whereas the remaining 73% is directly
or indirectly irrigated using groundwater. The Punjab province uses more than
90% of the total groundwater abstraction. Currently, 1.2 million private
tubewells are working in the country, out of which 85% are in Punjab, 6.4% are
in Sindh, 3.8% are in Khyber-Pakhtunkhwa, and 4.8% are in Baluchistan. The
total groundwater extraction in Pakistan is about 60 billion m3. The access to groundwater has helped farmers in securing food
for the increasing population. However, unchecked groundwater exploitation has
created severe environmental problems. These include rapidly falling
groundwater levels in the irrigated areas and increased soil salinization
problems. The groundwater levels in more than 50% of the irrigated areas of Punjab
have dropped below 6 m, resulting in increased pumping cost and degraded
groundwater quality. Despite hectic efforts, about 21% of the irrigated area is
affected by different levels of salinity. The country has introduced numerous
laws and regulations for the sustainable use and management of groundwater
resources, but the success has so far been limited. Besides less respect for
the law, unavailability of needed data and information, lack of political will
and institutional arrangements are the primary reasons for poor groundwater
management. Pakistan needs to revisit its strategies to make them adaptable to
local conditions. An integrated water resource management approach that brings
together relevant government departments, political leadership, knowledge
institutions, and other stakeholders could be an attractive option.
Keywords:
groundwater governance; soil salinity; irrigated areas; groundwater levels; Pakistan
1. Introduction
Groundwater irrigation plays a vital role in
boosting agricultural production and livelihoods of rural communities in many
parts of the world. For example, the area in South Asia equipped for irrigation
has tripled since 1950 [1]. India, Pakistan, and Bangladesh are the largest
groundwater users in South Asia, with an estimated annual extraction of about
320 billion m3 (bm3) (India = 230 bm3; Pakistan = 60 bm3; Bangladesh = 30 bm3) [2,3,4]. More than 85% is used for agricultural purposes,
compared to 40% in the rest of the world [1,5]. These three countries irrigate 48 million ha (mha)
using groundwater, approximately 42% of the global groundwater-fed cropland [6]. Diminishing surface water supplies and the desire to
expand the irrigated area to produce more food for the ever-increasing
population are the major factors behind this intensive groundwater use.
Furthermore, supply-driven policies of the governments and subsidized energy
and pumps have exacerbated the use of groundwater for agriculture in these
countries [7,8].
Dwindling surface water supplies due to
declining storage capacities and growing climate change concerns have
threatened the future of irrigated agriculture, which produces about 90% of the
total grains in Pakistan [9,10]. The arid and semi-arid conditions prevailing in most
parts of the country make irrigation mandatory for sustainable crop production,
as the evapotranspiration is high and rainfall is meager and unreliable [11]. More than 75% of this rainfall is received during the
monsoon season (July–September). The contribution of rain to agricultural
irrigation is about 30 bm3, which is only sufficient to meet 15% of the
crop water requirements and the remaining 85% is met through irrigation [12]. The scarcity and unreliability of surface water
supplies left farmers with no other option than to abstract groundwater to
fulfill irrigation water demands, regardless of its quality and the pumping
cost [3].
The surface water availability in the Indus
basin is 820 mm/ha/year, assuming a total canal supply of 130 bm3 and a serving area of 16 mha. This water availability is
far lower than the evapotranspiration requirements to support a year-round
basin-wide intensive cropping system practiced in the Indus basin. This shortfall
in surface water supplies is met through the exploitation of groundwater.
Groundwater has played a crucial role in thwarting water shortages and ensuring
food security for the rising population. The access to groundwater has helped
farmers to cope with the vagaries of surface supplies, diversify cropping
patterns, and transform uncertain crop yields into more sustained crop
production. However, the on-going unregulated and unplanned groundwater
abstraction is endangering the future of irrigated agriculture in the country.
In many irrigated areas, groundwater levels are falling, resulting in increased
pumping costs, and deteriorating groundwater quality. This situation has made
groundwater inaccessible for smallholder farmers. Besides, soil salinity problems
in irrigated areas are expanding, and many areas are under threat.
Despite the crucial role groundwater plays in
improving agricultural production and economic growth, its governance has not
received the needed attention. In the absence of an effective management
policy, it has become a pumping arms race; the person with the biggest pump
usually wins. Presently, groundwater withdrawals exceed renewals and are
turning this boon into a looming disaster [10,11,12,13,14]. Since two-thirds of the rural population are directly
or indirectly dependent on groundwater for their food security and livelihood,
country need to take critical steps to protect the rights of smallholder
farmers. One of the major bottlenecks in the management of groundwater is the
lack of sufficient data, and vigorous analysis of the available data to
comprehensively understand the dynamics of groundwater use in agriculture and
its impacts on the socio-economic conditions of the farmers and environment.
This paper reviews the historical development of groundwater use patterns and
examines the challenges of groundwater governance in large river basins such as
the Indus basin. The paper also reviews different strategies that have been
used in different countries for managing groundwater and analyzes why these
solutions did not work in the Indus basin. The outcomes of this paper will be
equally applicable for groundwater management in other river basins, such as
the Yellow River basin of China and Ganges-Brahmaputra basin in India and
Bangladesh.
2. The Indus Basin
Agriculture is an essential pillar of
Pakistan’s economy, because it contributes about 20% of the gross national
product (GDP) and employs 44% of the total labor force. More than 80% of the
population directly or indirectly depends on agriculture to earn their living.
The arable agricultural resource base is about 22 mha, 27% of the total land
area. About 16 mha are irrigated, and 6 mha are rain-fed. The irrigated area
produces more than 90% of the entire agricultural and livestock productions.
The irrigated lands are located in the areas between different rivers of the
Indus basin [15]. The climate in most parts of the country favors two
cropping seasons in a year: the winter growing season (November–April), and the
summer growing season (May–October). More than 85% of farms are smallholders
(0.5–5.0 ha). Therefore, crops are selected, to a small degree, to serve the
farmers’ household consumption and for livestock. The principal crops include
wheat, rice, cotton, sugarcane, fruits, vegetables, and pulses. The crop yields
are far below their demonstrated potential. In addition to water scarcity and
poor irrigation management practices, lack of necessary inputs such as fertilizer
and pesticides are primary reasons for the low yields.
The extensive contiguous Indus Basin
Irrigation System (IBIS) irrigates about 16 mha of land. The value of
agricultural output of the IBIS grows at an average annual rate of
approximately 3% [16]. After the Indus Basin Water Treaty of 1960, the
exclusive rights of three eastern Rivers (the Ravi, the Beas, and the Sutlej)
were given to India, while the three western rivers (the Chenab, the Jhelum,
and the Indus,) were given to Pakistan (Figure 1) [17]. The Indus River and its tributaries, on average,
bring 190 bm3 of water annually. This includes 179 bm3 from the three western rivers and 11 bm3 from the three eastern rivers. Most of this, about 130 bm3, is diverted for irrigation. About 50 bm3 flows to the sea, and 10 bm3 is the system losses (e.g., evaporation, seepage, and
spills during floods) [18,19].
Figure 1. Map of Pakistan with provincial
boundaries (Not at exact scale).
The IBIS consists of the perennial rivers, a
network of unlined canals, and distribution channels. It is a supply-based
system, and water is delivered to farmers weekly in a pre-determined quantity
based on their landholding. The delivery efficiency of the irrigation system is
low, ranging from 35% to 40% from the canal head to the crop root zone. The
existing water storage capacity is 30 days of Indus River runoff, very low
compared to 900 days for the Colorado and Murray Darling rivers, 500 days for
the Orange River in South Africa, and 120–220 days for the Peninsular Rivers in
India [20].
Increasing siltation will decrease the
existing storage capacity of Pakistan by 57% by 2025. The Pakistan Water Sector
Strategy estimates that the country will be required to increase its storage
capacity by 22 bm3 by 2025 to meet the projected annual
water demand of 165 bm3 [21]. Over the last 50 years, Pakistan has failed miserably
in the development of new water storages and related infrastructure, due to
increasing financial and environmental concerns. Under the present
socio-economic and political circumstances, it will remain a challenge in the
coming years. Therefore, groundwater-based irrigation will be crucial for food
security and the economic development of the country.
3. Groundwater
Development in Pakistan
Pakistan is the third-largest user of
groundwater, consuming about 9% of the global groundwater abstraction and
occupying 4.6% of the total groundwater-irrigated area of the world [13,22]. The extensive use of groundwater in the country
started in the 1960s, when 16,700 drainage wells with a discharge capacity of
0.80 m3/sec were installed under the
government-funded Salinity Control and Reclamation Projects (SCARPs). The SCARP
tubewells were installed to control water-logging and salinity problems in 2.6
mha of the irrigated lands [7]. Due to low salinity (1–2 dS/m), the pumped groundwater
was released into the canal system to solve disposal problems and to increase
irrigation supplies at the farmgate.
The demonstration of the SCARP model motivated
farmers to install their own tubewells, resulting in the massive development of
private tubewells, i.e., from merely 30,000 in 1960 to over 1.2 million in
2018. Out of these, more than 90% are only working in the Punjab province.
During this period, the irrigated area in Punjab was almost doubled (from 8.6
to 16 mha), and the groundwater contribution to the overall irrigation water
supply at the farmgate increased from 8% to 75% [15,23]. The remaining 4.4% are in Sindh, 1.8% are in Khyber
Pakhtunkhwa (KPK), and 3.8% are in Baluchistan. In Punjab, the canal system
contributes to more than 80% of the total groundwater recharge; therefore,
canal systems have become more of a recharge process than an efficient water
supply system [24].
The shallow depth and better quality of
groundwater favored the massive development of private tubewells in Punjab. In
Punjab, only 23% of the area has poor groundwater quality, compared to 78% in
Sindh [19]. For this reason, the development of private tubewells
in Sindh remains limited. In Baluchistan, groundwater levels are deep, and
turbine/submersible pumps are needed to run these tubewells. The average
installation cost of a deep electric tubewell (>20 m) is USD 10,000,
compared to USD 1000 for a shallow tubewell (<5 m). Increasing energy prices
have made it very expensive to extract groundwater from deeper depths using
electric tubewells. The installation and operational cost of deep electric
tubewells are beyond the capacity of poor farmers.
In Pakistan, the cost of pumping 1000 cubic
meters of water from a shallow tubewell is USD 4.5, compared to USD 15 from a
deep tubewell [25]. Of course, these costs are affected by varying energy
prices. In the Baluchistan province, electricity is subsidized to make the
groundwater pumping from deeper depths affordable for smallholder farmers.
However, evidence exists that the primary beneficiaries of this subsidy are
still large landholders who own deeper wells. The provision of subsidized
electricity has further compounded the problem of groundwater overdraft in many
parts of Baluchistan [3,26].
Figure 2 shows that about 85% of the tubewells in the
Punjab province are diesel operated, and the remaining 15% are electric. Over
the last 20 years, electric tubewells have increased from 12% in 2000 to 16% in
2018 [15]. Farmers prefer diesel tubewells
due to low installation and operational costs compared to electric tubewells.
Moreover, diesel tubewells are more convenient for small and fragmented
landholders. Most of the diesel tubewells have a capacity of 0.030 m3/sec and use Chinese pumps of 10–12 hp. The total groundwater
potential of Pakistan is about 68 bm3, out of which 60 bm3 is currently exploited [23,25]. This indicates that the groundwater resource is
almost exhausted, because the remaining groundwater is in the regions where it
is not easy to abstract due to economic and technical reasons [3]. Most of the groundwater pumped for irrigation is the
water “recharged” from the irrigation network and farmer fields. Due to this
inter-connectivity, assessing the total available water resources needs much
caution [26,27].
Figure 2. Temporal development of private
tubewells in the Punjab province of Pakistan (Source: Punjab Agricultural
Statistical Department).
In Punjab, more than three million farmers are
directly or indirectly benefiting from tubewells. On average, one in four farming
families owns a small tubewell, whereas the others purchase water from their
neighboring farmers through informal groundwater markets [28,29]. The investment in private tubewells in Punjab is
estimated at USD 750 million. The unrestricted access to groundwater through
these tubewells has helped farmers to increase their crop yields, diversify
cropping patterns, and to cope with extreme events such as droughts. Farmers in
many areas have started growing water-demanding crops such as rice and
sugarcane due to better economic returns.
The groundwater development was encouraged by
easy access and acceptable groundwater quality and cropping patterns. In the
rainfed and dry areas, groundwater is available at greater depths and in
smaller quantities. Therefore, it was not affordable for smallholder farmers.
In the canal command areas, groundwater is shallow and of much better quality
due to excessive seepage from unlined canals and irrigation fields. Besides,
irrigation water requirements are high due to high cropping intensities. This
situation prompted farmers to install small tubewells to extract groundwater to
feed their thirsty crops, especially rice and sugarcane. Therefore, in these
areas (Figure 3, green bars), tubewell density increased. This
situation not only helped farmers to expand the cultivated area for rice and
sugarcane in these districts, but also increased crop yields by 50–100%. The
overall impact of these developments was improved income for farms and a more
secure livelihood for farmers. Groundwater also acts as a last resort for
providing drinking water for humans and animals in the rural and desert areas
of the country, especially during the low-rainfall years [3,28].
Figure 3. Number of tubewells in different
districts in the Punjab Province of Pakistan (Source: Punjab Agricultural
Statistical Department).
4. Patterns of
Groundwater Use in Pakistan
The groundwater use patterns vary in different
provinces. For example, groundwater use in Sindh province is minimal due to
quality concerns. In the Khyber Pakhtunkhwa and Baluchistan provinces,
groundwater exploitation is costly due to deeper depths and aquifer
characteristics. In Punjab, the use of groundwater is widespread due to its
existence at shallow depths and relatively good quality. The groundwater use in
different parts of Punjab depends on many factors, such as cropping patterns,
cropping intensity, agro-climatic conditions, and available groundwater
quality. There are three distinct climatic zones in the Punjab province (Table 1). Upper Punjab has an average annual rainfall of
above 500 mm (high rainfall zone), central Punjab receives 300–400 mm (medium
rainfall zone), and lower Punjab has 100–150 mm rainfall (dry zone). The
cropping patterns in these zones differ based on the availability of surface
water and groundwater [19]. For high rainfall zones, groundwater use is low
compared to small and medium rainfall zones, despite rice being a major crop
grown in these areas. In the areas where wheat–cotton cropping rotation is more
common, groundwater use is relatively small due to the lower water requirement
of these crops. In the sugarcane and fodder-dominant areas, groundwater use is
high due to high water demand.
Table 1. Cropping
patterns, cropping intensity and groundwater quality in different agro-climatic
zones.
During the last 50 years, agriculture in
Pakistan has changed from surface water to largely groundwater-fed irrigation.
The increasing trend of groundwater use has played a pivotal role in enhancing
the irrigated area and improving crop yields. Figure 4 shows that between 1960 and 2015, the area
irrigated exclusively with canal water has reduced by 38% (from 8.59 to 5.37
mha), whereas the area irrigated by groundwater has increased by 390% (from 2.9
to 14.3 mha). This includes areas where groundwater is used both in isolation
or in conjunction with the canal water.
Figure 4. Groundwater use patterns in Pakistan
(Source: Pakistan Statistical Bureau).
Until 1980, groundwater was only supplementing
surface water supplies because the area under cultivation was less, and the
need for irrigation water was rather conservative. After this period, farmers
started extensive exploitation of groundwater to increase the cultivated area
of wheat and other cash crops such as rice and sugarcane. During the period
1980–2017, the cultivated area of wheat, rice, and sugarcane increased by 33%,
42%, and 37%, respectively (Figure 5). The expansion in the areas of water-intensive
crops (i.e., sugarcane and rice) was only possible due to the accessibility of
groundwater, as the surface water supplies remained mostly unchanged or even
started declining in many areas. Due to the expansion in the cropped area, the
total production of these three crops almost tripled from 1980 to 2017. Today,
Pakistan produces about 26 million tons of wheat, in comparison to 8.7 million
tons in 1980 [24,31]. As the production of these crops is more than
domestic consumption, a sizable proportion is exported.
Figure 5. Development of cultivated area and
production of three major crops in Pakistan (Source: Punjab Agricultural
Statistical Department).
In Punjab, more than 75% of the farmers mix
groundwater with the surface water (conjunctive water use) to increase
irrigation supplies and dilute salts [26]. However, in the areas where the groundwater is of
acceptable quality for irrigation (head-reaches of canals), farmers also use
groundwater alone for irrigation without mixing it with the canal water. Due to
deficient and erratic canal supplies at the tail-reaches of the canal system,
farmers also started using groundwater in isolation without considering its
quality. However, this venture did not continue for long as they soon realized
that their land was becoming salinized.
Figure 6 shows that, on average, 24% of the
cultivated area is irrigated by canal water alone. About 23% of the total
cultivated area is irrigated solely by groundwater, and the remaining 53% is
irrigated through conjunctive use of surface water and groundwater. This means
that 76% of the cultivated area in Punjab is directly or indirectly dependent
on groundwater to meet its irrigation demand. The area irrigated by canal water
has decreased by about 0.40 mha during the last 20 years. In contrast, the area
irrigated by groundwater alone has remained unchanged with small variations
between different years. Noticeably, an additional 1.3 mha has adopted
conjunctive use in Punjab over the last 20 years.
Figure 6. Area irrigated (‘000’ ha) by different
modes of irrigation in the Punjab province (Source: Punjab Irrigation
Department).
The sustainable production of major crops such
as wheat, rice, and sugarcane is mainly dependent on the unlimited supply of
groundwater. These three crops consume more than 80% of the total groundwater
abstracted in Punjab. The availability of groundwater has transformed the
trends of uncertain crop yields to a more stable and increased crop production.
Farmers who have access to both surface water and groundwater earn five times
more than those restricted to surface water supplies only [32].
Figure 7 illustrates that, on average, 31% of the
sugarcane area is irrigated by canal water, followed by 23% for wheat and 12%
for rice. The remaining cultivated areas of sugarcane and wheat crops are
irrigated using groundwater. For both crops, 52% of the cultivated area is
irrigated through conjunctive use of surface water and groundwater. About 26%
of the wheat area used groundwater alone, followed by 17% for the sugarcane.
For the rice crop, only 12% area was irrigated by canal water, and the
remaining 88% was irrigated using groundwater (57% through conjunctive use of
groundwater and surface water) and 31% by groundwater alone. This situation
indicates the vital role of groundwater in enhancing agricultural production in
the country. Without groundwater, production levels of three major cash crops
cannot be sustained, with severe consequences for the food security and
socio-economic development of the country.