Water development for irrigated agriculture in Pakistan: past trends, returns and future requirements - Hafeez Akhtar Randhawa

Hafeez Akhtar Randhawa, Federal Secretary

Ministry of Food, Agriculture and Livestock, Pakistan

AVAILABLE WATER RESOURCES

Precipitation

Incident precipitation and river flows are the two major sources of surface water used to meet the requirements of agriculture and other sectors. Mean annual rainfall in Pakistan varies from less than 100 mm in Balochistan and parts of Sindh provinces to over 1 500 mm in the foothills and northern mountains. About 60 percent is received during the July to September monsoon. Most summer rains are not available for crop production because of rapid runoff during torrential showers. The contribution of rainwater to crops in the Indus Basin Irrigation System (IBIS) is about 16.5 billion m³, some 10 percent of the mean annual river flow (Ahmad, 1993a).

The current drought was so severe that snowfall during the 2000 - 2001 winter season was significantly less than in normal years. Snow records are not available prior to 1999, but it is expected that snowfall might be less than the historical minimum or very close to that. Thus snowmelt available during the coming Kharif season will be much less than the mean flows.

Surface water resources

Pre - storage resources

Glacier melt, snowmelt, rainfall and runoff constitute the river flows. Inflow measurement facilities have been established at the rim of the Indus River tributaries and are thus referred to as rim station inflows. The rim stations for the western rivers are located at Tarbela, Attock, Mangla and Marala for the Indus, Kabul, Jhelum and Chenab rivers, respectively. The rim stations for the eastern rivers are located at Balloki and Sulaimanki for the Ravi and Sutlej rivers.

River flows are limited in the Rabi season because of limited glacier - and snowmelt and low rainfall during in the winter season. Western rivers provided 173 billion m³ surface water in an average year during the pre - storage period of 1937 to 1967. The bulk of the river flow was during the Kharif season, with more than five times the flow of the Rabi season. Variability in flows of the eastern rivers was even higher than the western rivers. Before the Mangla and Tarbela storage dams were built, the eastern rivers contributed 26 billion m³ of water to the Indus River system in an average year - of which 84 percent was during the Kharif season (Table 1).

The contribution of the eastern rivers to the annual total inflow of the Indus River system was 13 percent, and 11 percent during the Rabi season - a significant contribution (as seen in Table 1).

Post - storage resources

Seasonal and annual river flows in the Indus river system are highly variable (Warsi, 1991; Kijine and Vander Velde 1992; Ahmad, 1993a; Mohtadullah, Rerman and Munir 1991). Analysis of daily and monthly flows indicated a similar trend (Bhatti, 1999). This variability restricts the assessment of the real contribution of storage in regulating flows of the river system; however, data were analyzed to evaluate the effect of key influences on the river flows in both western and eastern rivers.

TABLE 1

Variability of rim - station inflows to Indus River system (pre - storage period)

Data Source: Water Resources Management Directorate, WAPDA.

River flows were limited in the Rabi season because of limited glacier - and snowmelt and low rainfall in winter. The western rivers provided 162 billion m³ of surface water in an average year during the post - storage period, 6.4 percent less than the pre - storage period. The bulk of the river flow was during the Kharif season, which was five times the flow in the Rabi season. Variability in eastern river flows was even higher than in the western rivers. After the construction of the Mangla and Tarbela storage dams, the eastern rivers contributed about 10.7 billion m³ of water to the Indus River system in an average year - 77 percent in the Kharif season (Table 2). The eastern rivers contribute 6 percent of annual total inflows - just 5.6 percent in the Rabi season.

Variability in river flows is a major limitation in the development of run - of - river type irrigated agriculture in the Indus Basin, especially to meet crop irrigation requirement during low flow period of the Rabi season and early and late Kharif season.

The recent drought was so severe that annual river flows downstream of the Kotri barrage during 2000 - 2001 were expected to be less than the historical minimum of 118.5 billion m³ since 1922. This has created a situation of water crises in Pakistan and deepens interprovincial water conflicts.

Flows to the Arabian Sea (downstream of the Kotri barrage)

Annual variability of river flows downstream of the Kotri barrage has been very high. In normal years (50 percent probability), annual flow was reduced from 95.4 to 48.4 billion m³ during pre - and post - Tarbela periods. The percent reduction in annual flows in the dry years (10 percent probability) was higher than during normal years, when flows were reduced from 31.6 to 13.5 billion m³ during pre - and post - Tarbela periods (the probability of a dry year was one in five years in the pre - Tarbela period). The percentage reduction in wet year annual flows (>50 percent probability) was relatively less than in normal and dry years (see Table 3).

TABLE 2

Variability of rim - station inflows to Indus River System (post - storage period)

Data Source: Water Resources Management Directorate, WAPDA.

TABLE 3

Flow variability to Arabian Sea (downstream Kotri Barrage), pre - and post - Tarbela periods

Data Source: Water Resources Management Directorate, WAPDA.

Rabi season flows in normal years (50 percent probability) were reduced from 7.1 to 1.7 billion m³ during pre - and post - Tarbela periods, respectively. The effect was more pronounced in dry years, where seasonal flows were even less than 0.5 billion m³ in one of every four years. Reduction in seasonal flows was also observed during the wet years (>50 percent probability).

In summary, construction of the Kotri barrage reduced seasonal and annual flows below the Kotri due to the canal diversions. Seasonal and annual flows were further reduced during post - Mangla and post - Tarbela periods due to further increases in canal diversions at the Kotri barrage. Canal diversions at the Kotri barrage were increased from 5.42 to 10.8 billion m³ (a 100 percent increase) during the post - Tarbela period. The probability of dry years was doubled after Tarbela compared to the pre - Tarbela period - a serious concern for downstream flows to maintain the delta ecosystem. The recent drought was so severe that annual river flows downstream of the Kotri Barrage in 2000 - 2001 will be less than the historical minimum flows of 10 billion m³ since 1922.

Groundwater resources

Pre - storage resource picture

The Indus Basin represents an extensive groundwater aquifer covering a gross command area of 16.2 million ha. The water table was well below the surface and the aquifer was in a state of hydrological equilibrium before the development of the canal irrigation system. The recharge to aquifer from rivers and rainfall was balanced by outflow and crop evapotranspiration. When the canal irrigation system was introduced, percolation to the aquifer increased in irrigated areas of the Indus basin resulting in the twin menaces of waterlogging and salinity.

Although, there are disadvantages in having a high water table, it was used for irrigation by tubewells in fresh groundwater zones. The groundwater contribution for irrigation was 12 billion m³ in the pre - storage period, 11 percent of the total water available for agriculture.

Post - storage resource picture

Estimated recharge to groundwater in the Indus Basin is 56 billion m³, of which 36 billion m³ occurs in areas of usable groundwater (Zuberi and Sufi 1992). The additional conveyance losses in the IBIS due to Tarbela contributed 10 percent to the overall recharge of groundwater (Ahmad 1993b). The 1979 WAPDA basin - wide survey indicated that the water table in 42 percent of the Indus Basin was less than 3 m and was classified as waterlogged, and the water table in 22 percent of the area was less than 2 m. In Sindh province about 57 percent of areas where the water table is less than 3 m (Table 4) was affected by waterlogging.

The 1979 basin - wide surveys were actually conducted from 1976 to 1978 and therefore represent early post - Tarbela conditions. Although, groundwater use has increased significantly in the last two decades, waterlogging still affects large tracts of land. About 22 percent of the Indus basin command area has a water table within 1.5 m. This rising water table indicates a worsening situation but it cannot be seen solely as a result of the Tarbela and Mangla reservoirs. Mangla/Tarbela - related increased waterlogging could be attributed to the lack of appropriate drainage facilities and inadequate improvements in irrigation management. The major reason was the failure or transition of SCARP projects and 10 percent added recharge to groundwater due to additional surface supplies from Tarbela.

Additional water supplies from the Mangla and Tarbela storage dams diverted to the newly constructed canal commands also contributed to recharge of groundwater. One example is the Chashma Right Bank Canal (CRBC) command area, where a rise in the water table has been observed to create a freshwater aquifer (Alurrade, 1998). However, for sustainability purposes, subsurface drainage has to be provided to control water table depth. In fact the rise in water table was faster than expected and required an additional loan to introduce drainage.

TABLE 4

Indus plain provincial trends of water table depths and areas affected

NOTE: mha=million hectares

WATER QUALITY

Surface water quality

The water of the Indus River and its tributaries is of excellent quality. Total dissolved solids (TDS) range from 60 to 374 ppm, safe for irrigated agriculture, domestic and industrial uses (Bhutta 1999; PWP 1999).

TDS in the upper reaches at various rim stations ranges from 60 ppm during high flow to about 200 ppm during low flow. Water quality deteriorates downstream but remains well within permissible limits, with TDS at Kotri barrage in the lower reaches of the Indus ranging from 150 to 374 ppm. However, the TDS of tributaries such as the Gomal River at Khajuri, the Touchi River at Tangi Post and the Zhob River at Sharik Weir range from 400 to 1 250 ppm (IWASRI 1997).

Indiscriminate, unplanned disposal of agricultural drainage effluent (polluted with fertilisers, insecticides, pesticides), untreated sewage and industrial waste loaded with heavy metals and other toxic materials, is flowing into rivers, canals and drains, causing water quality deterioration in downstream waterways and water bodies. In 1995 an estimated 34 billion litres of untreated water was discharged daily into rivers, canals, drains and water bodies (Saleemi 1993). It was estimated that 350 and 250 million gallons per day (mgd) of raw sewage was produced in Karachi and Lahore, respectively, and that most was discharged untreated into varied waterways (Hussain 1995). Downstream this polluted water is consumed by people and causes numerous water - borne diseases.

At current growth rates, Pakistan's population is estimated to increase from 139 million in 1998 to 208 million in the year 2025, an increase of nearly 48 percent (Bhutta 1999). If no remedial measures are taken, the quantity of untreated sewage and industrial effluents will grow by at least the same proportion, further polluting surface waters so vital to meet the needs of human beings, livestock and plants. Pakistan's need to control pollution of surface water and to improve its quality is urgent.

Groundwater quality

Total annual groundwater potential in Pakistan is estimated at 67.9 billion m³. The annual groundwater pumpage has increased from 4 billion m³ in 1959 to 59 billion m³ in 1996 - 1997. About 79 percent of the Punjab and 28 percent of Sindh have fresh groundwater suitable for agriculture (Afzal 1999; Bhutta 1999). Since most of the easily exploitable surface water resources have already been tapped, the future demand of water for agriculture, people and nature will have to be met largely through water conservation and further exploitation of already over mined groundwater resources.

Quality of groundwater varies widely, ranging from less than 1 000 ppm to more than 3 000 ppm. Some 5.75 million ha are underlain with groundwater having salinity less than 1 000 ppm, 1.84 million ha with salinity ranging from 1 000 to 3 000 ppm and 4.28 million ha with salinity more than 3 000 ppm.

Although investments in drainage have been significant in Pakistan during the last two decades, waterlogging still affects large tracts of land (World Bank 1994). Salinity and sodicity also constrain farmers and affect agricultural production. These problems are further exacerbated by the use of poor quality groundwater (Kijne and Kuper 1995). In fresh groundwater areas, excessive pumping by private tubewells leads to mining of the aquifer (NESPAK 1991) and redistribution of the groundwater quality (Zuberi and Sufi 1992; WRRI, MONA and IIMI 1999).

Recharge to the freshwater zone due to the additional supplies from Tarbela has contributed significantly in maintaining groundwater quality. However, recharge to the brackish groundwater zone created serious quality concerns for the disposal of the saline effluents despite creating a top layer of potable water for the concerned population (Ahmad 1993a). This problem was mainly due to the approach followed for drainage of area under the SCARPs in brackish groundwater zone, where saline groundwater (SGW) was pumped from deeper depths (Ahmad 1990).

Mining of groundwater, which is presently occurring in many areas, will cause intrusion of saline groundwater into the fresh groundwater areas. In addition, seepage of water from farmland will add dissolved fertilisers, pesticides and insecticides to groundwater. This will further increase pollution of groundwater and deteriorate its quality. The use of polluted groundwater for drinking may cause serious health hazard and its use for irrigated agriculture may adversely affect production potential of irrigated lands due to aggravation of the problem of salinity, sodicity and specific ion effects on crops and plants. It is essential to minimise groundwater pollution to improve its quality as far as possible through regulation of groundwater extraction and/or increasing the recharge in areas where mining of groundwater is taking place.

PAST TRENDS IN WATER USE

Agricultural water use: surface water

Indus Basin canal diversions

Canal diversions represent the total amount of water diverted at all barrages constructed on IBIS rivers. Water diverted to individual canals at their offtake from the barrages is a good indicator of the contribution and effect of the storage reservoirs (Mangla and Tarbela) including the IBP. A considerable increase in canal diversions of about 9 billion m³ was observed during the post - Mangla period. A further increase of 12 billion m³ was observed during the post - Tarbela period. Of this, the major increase was in the Rabi season (9.6 billion m³ per annum) as shown in Table 5.

The contribution of the Tarbela dam to canal diversions during the Rabi season was almost 26 percent, significant because most staple food is grown then. However, the main objectives of the Tarbela dam were to provide storage for replacing water of existing canal commands of 1.8 million ha dependent on eastern rivers flow and improvement of supplies to canals off - taking from the Indus main channel commanding 6.9 million ha.

However, there was variability in the canal diversions in both the seasons. The percent variability between the highest and lowest post - Tarbela canal diversions was 25 and 17 percent during the Kharif and Rabi seasons, respectively. This shows that the stochastic nature of the river flows also has an effect on the canal diversions, in addition to the reduced storage capacity of the Tarbela (Table 6). This information along with shortages and surpluses can be used for planning new irrigation projects (Ahmad and Kutcher 1992).

TABLE 5

Historical canal diversions to IBIS under key influences

Data Source: Water Resources Management Directorate, WAPDA.

The recent drought was so severe that annual canal diversions during 2000 - 2001 will be less than the historical minimum diversions of 116.5 billion m³ in the post - Tarbela period (1975 - 2001). The reduced canal diversions to the extent of 30 percent of the mean are expected, which might be some 90 billion m³. This reduction in canal diversions during the Rabi season 2000 - 2001 has adversely affected crops such as wheat, chickpeas, sugarcane and vegetables, as well as orchards. The drought was continuing and might be severe during April - June 2002, which will further affect sugarcane and also adversely affect the planting of cotton and rice crops.

Irrigation system losses and overall irrigation efficiency

The Indus River flows through alluvial plains and thus its losses and gains assume greater importance than would otherwise be the case (Ahmad 1993b). In its system losses generally occur in the rising stage from April to July. During falling flows, covering the periods from end of July to September and from October to March, the rivers usually gain water. Analysis of annual historic gains and losses was conducted using the data between the period from 1940 - 1941 to 1993 - 1994 for the Kharif and Rabi seasons (Table 7).

Earlier studies revealed that conveyance losses in canals varied between 15 to 30 percent (Ahmad 1993b; Harza 1963; IACA 1966; LIP 1966). The Water Sector Investment Planning Study (WSIPS, 1990) provided a synthesis of the work done by WAPDA (1979) on canal conveyance losses for 24, 5 and 14 canal commands in the Punjab, NWFP and Sindh provinces, respectively. The average canal losses computed were 23, 12 and 20 percent for the canal commands of the Punjab, NWFP and Sindh provinces, respectively. These losses were about 21 percent for the whole basin.

TABLE 6

Variability of post - Tarbela canal diversions in IBIS

Data Source: Water Resources Management Directorate, WAPDA.

TABLE 7

River gains and losses in the Indus River System

Data Source: Water Management Directorate, WAPDA

Systematic work on watercourse loss measurement was initiated jointly by Colorado State University and WAPDA. Based on two systematic studies of 40 and 61 watercourses, actual losses were 47 and 45 percent, respectively. Field application losses were about 25 percent (Ashraf, 1977; WAPDA 1979; Trout and Kemper 1980; PARC - FAO 1982). Average losses of 21, 40 and 25 percent were used to compute losses from canals, watercourses and fields, respectively, in this paper. These losses provided canal, watercourse and field application efficiency of 79, 60 and 75 percent, respectively. Thus the overall irrigation efficiency is 36 percent (Ahmad 1990).

System losses corresponding to canal supplies in IBIS ranged from 82.5 to 84 billion m³ during the post - Tarbela period, or about 64 percent of water delivered to IBIS (Table 8). In fresh groundwater areas, this induced recharge resulted in accelerated installation of tubewells to exploit the resource.

Groundwater

Groundwater contribution

From 1976 to 1997, the groundwater contribution to irrigated agriculture has doubled, rising from 31.6 to 62.2 billion m³ (GOP 1998). The country has made considerable progress in the development of innovative and indigenous tubewell technology. However, with higher electricity tariffs and diesel fuel prices and soil salinity in marginal quality zones, there was a decline in groundwater pumpage during 1997 - 1998. It was about 50 billion m³ - a significant decrease (Table 9). However, groundwater contributed 38 percent of surface water available at the canal head.

TABLE 8

Irrigation system losses corresponding to canal supplies to IBIS

Another contributing factor was the transition of public tubewells under SCARPs, where communities refused to take over deep tubewells because of high O&M costs. SCARP transition projects were aimed at reducing public involvement in the groundwater sector by closing down or transferring public tubewells to the water users (World Bank 1988).

Droughts during 1999 - 2000 and 2000 - 2001 forced farmers to install tubewells to meet shortfalls in canal supplies. It is expected that canal supplies during 2000 - 2001 will be significantly less than the historical average. Thus the groundwater abstraction was much more than the recharge; rather in certain areas farmers faced problems of the lowering of the water table.

Tubewell development

Enhanced power generation from Tarbela and the government policy of price incentives for electric power motivated farmers to install electric tubewells. Consequently, there was more than threefold increase in the number of tubewells in 1990 - 91 as compared to the situation before Tarbela. The innovative and low cost development of tubewell technology in the country further motivated the farmers to install diesel - operated tubewells.

Progressive increases in electricity tariffs starting in the early 1990s resulted in stagnation of the growth of electric tubewells. However, a twofold increase in diesel tubewells was observed during 1990 to 1995. This is a clear indication of the effect of Tarbela and power policy of the government during the late 1970s and 1980s on the growth of tubewells and development of innovative tubewell technology (Table 10).

The drought of 2000 - 2001 was so severe that farmers in the Punjab and Sindh provinces have installed tubewells at a very rapid rate. It was expected that about 60 000 tubewells or lift irrigation systems were to be installed in 2001 to meet the historical shortfall in canal supplies.

TABLE 9

Pre - and post - Tarbela groundwater contribution to irrigation water supplies

Source: Agricultural Statistics of Pakistan, Ministry of Food, Agriculture and Livestock, 1998.

* Base year of 1965 - 66 is used for computations.

** Average value of canal diversion of 130 billion m³ is used for computations.

TABLE 10

Tubewell development in Pakistan

Source: Agricultural Statistics of Pakistan, Ministry of Food, Agriculture and Livestock, 1998.

Domestic water supply

The water supply and sanitation sector in Pakistan is characterised by an extremely low level of coverage, particularly in rural areas. Presently, 80 percent of the urban population have access to piped water supply, whereas only 11 percent of the rural population benefits from this facility (PWP 1999). Table 11 shows the present water supply to various urban centres in Pakistan.

Water supply systems in Pakistan's urban centres are based on either using surface water or groundwater abstraction through tubewells. The cities which depend on surface water for their drinking water needs include Islamabad, Karachi and Hyderabad. Lahore, Peshawar, Faisalabad, Abbotabad and Quetta are mostly supplied by groundwater.

Nearly all cities depending on surface supplies face moderate to acute shortages, but Lahore and Peshawar are somewhat better off due to a high yielding aquifer.

Rural areas depend on groundwater for domestic water where available, but in irrigated areas underlain with saline groundwater, canal waters are used to satisfy domestic requirements. Outside the canal commands, where groundwater cannot be depended upon, rural water supply depends on the available stream flows in upland areas or on rainfall collected in natural depressions, such as Tobas in the Cholistan desert. In such arid locations, the local populace must travel long distances to procure drinking water - a task assigned to women.

TABLE 11

Estimated water and sewage flows in cities

* gpcd - gallons per capita per day

** mgd - million gallons per day

It is estimated that present water demand for combined domestic and industrial uses is 3 302 mgd, whereas available water for the purpose is 2 369 mgd (PWP 1999; NESPAK 1998). Therefore, there is a net deficiency of 22 percent of total domestic water requirement.

Severe drought has affected domestic water supply availability. Surface water availability in the Simly dam in Islamabad has fallen to 40 percent of the requirement: the Capital Development Authority is rationing water on alternate days to the citizens of Islamabad.

Sanitation and sewerage

Pakistan's coverage for sanitation services is lower than the water supply coverage, i.e. only 60 percent and 13.5 percent in urban and rural areas, respectively. In most cities, wastewater from the municipal areas as well as industrial effluent is disposed untreated to natural surface water bodies. Table 11 shows the sewage generation of several urban centres.

In urban areas, sewerage consists of sewage collection and a disposal system. In cities sewage is collected through RCC pipes and open drains. Collected sewerage is disposed of in nearby water bodies through gravity or by inducting sewage pump stations in the system. In areas where sewage collection system is non - existent, sewage is discharged into groundwater through soakage wells, sometimes even without passing through septic tanks.

In rural areas, proper collection and disposal is almost non - existent. Sewage is collected through open drains and disposed of in open fields, where it usually forms huge ponds.

At present, there is little treatment of effluent in municipal areas. Only a few cities in Pakistan have proper treatment facilities. According to a recent study, most plants are not in operation.

Industrial water use

Few industries have proper effluent treatment facilities. Generally multinational or export - oriented factories are forced to have treatment facilities.

Major industrial estates are found in Lahore, Faisalabad, Karachi, Hyderabad, Peshawar, Hattar, Kasur and Sialkot. The estates discharge effluent without treatment into nearby streams, to flow by river to the sea. Disposal of untreated industrial waste from isolated plants is allowed in open fields or nearby water bodies. Such ponds can be seen in various industrial estates.

Past trends and returns in irrigated agriculture

Irrigated and cultivated areas in IBIS

In the pre - Tarbela period, there were considerable water shortages and the actual water application to crops was only about three - fourths of the actual irrigation requirement. The transfer of Indus water to priority areas aimed to increase canal flows up to the limit of canal capacities. The irrigated area projected for the years 1975, 1985 and 2000 was 14.1, 16.4 and 17.9 million ha, respectively. The total cultivated area projected for those years was 19.4, 22.0 and 23.8 million ha respectively (Table 12).

Analysis of projected and actual areas in IBIS indicates that actual irrigated areas during 1997 - 1998 was 18.0 million ha, slightly higher than projected for the year 2000 by the Lieftinck Report of 1968. The actual cultivated area during 1997 - 1998 was 22.0 million ha, 7 percent less than projected for the year 2000 by the Lieftinck Report. This shows that the irrigated area target has been achieved (Table 12) but the total cultivated area target was not achieved as per projections for the post - Tarbela period.

As a result, there was a considerable expansion in canal irrigation in the Indus basin from 10.1 million ha in 1974 - 1975 to 14.7 million ha in 1997 - 1998. The 4.6 million ha increase during the post - Tarbela period can be attributed to additional supplies from the Tarbela dam and other diversion schemes. Tubewell irrigation increased from 2.8 million ha in 1974 - 1975 to 3.2 million ha in 1997 - 1998 (only tubewell commands). In addition, within the 1997 - 1998 canal command area (6.9 million ha), tubewells provided water to supplement canal supplies, while in 1974 - 1975 this facility was not available. Tubewell installation within the Punjab canal command area was concentrated in the Mangla command.

TABLE 12

IBIS projected and actual, irrigated and cultivated areas

NOTE: mha=million hectares.

Source: Lieftinck Report, Vol. I, 1968; Agricultural Statistics of Pakistan, Government of Pakistan.

Cropped areas in IBIS

At the macro level, a significant change in cropping patterns resulted from increased availability of water from the Tarbela dam. Increased cropped areas of food grains and cash crops such as wheat (36 percent), rice (39 percent), cotton (44 percent) and sugarcane (52 percent) were reported, while cropped areas of coarse grains and conventional oilseeds decreased. The overall increase of cropped areas was 39 percent (Table 13).

Although cropped areas were not in the Lieftinck Report, it can be estimated from cropping intensity. Thus actual cropped area was less than projected in the post - Tarbela period.

TABLE 13

Cropped area of selected crops in Indus Basin irrigated agriculture

Source: Agricultural Statistics of Pakistan, Government of Pakistan.

R = rabi; K = kharif; A = annual.

Land in the Indus basin is not a limitation. Irrigation is essential for crop production because of an arid environment, where rainfall contributes 10 - 20 percent of crop evapotranspiration in major parts of the IBIS. However, increased number of tractors, availability of planting machinery, credit support helped to increase cropped area. The increase in population was another reason, which influenced the increase in cropped area.

The major rabi crops in the Tarbela command area are wheat, fodder and horticultural crops. Sugarcane also needs irrigation during rabi season and thus competes for water with rabi crops. The trend of rabi crop areas in Tarbela shows considerable increases in area under wheat, fodder, sugarcane and horticultural crops. Wheat is a leading food grain for human consumption, while its straw is a source of cheap roughage for livestock. Generally, farmers consider water as a key input; with sufficient water availability; they normally increase cropped area.

Increased planting of sugarcane is primarily due to availability of additional irrigation water from the Tarbela reservoir as it is a high water demand crop. Other factors that contributed towards this increase were the development of the sugarcane industry and the road infrastructure, both providing necessary backward and forward linkages for growth.

Cropping intensity

In the Lieftinck Report, projected cropping intensities were given for Punjab and Sindh provinces, instead of the Indus Basin as a whole. In the Punjab irrigated area, actual intensity was 122 and 117 percent in 1985 and 1998, respectively, compared to projected values of 131 and 150 percent. In Sindh, actual cropping intensity was 124 and 132 percent in 1985 and 1998, compared to the projected 115 and 137 percent (Table 14). Increased cropping intensity in the post - Tarbela period was less than projected. The low cropping intensity could be attributed to problems of waterlogging and salinity, marginal quality groundwater use, increased areas of high water demand crops and insufficient improvements in irrigated agriculture.

As a result of increased canal diversions from 95 billion m³ in 1960 to 126 billion m³ at present and changes in the macro - economic environment, Indus basin farmers have increased their annual cropping intensities from the original design of 50 to 70 percent (over 100 years ago) to an average 120 percent in 1993 - 1994 (John Mellor Associates and Asianics, 1994). The present study confirms these observations - a cropping intensity of 117 percent was achieved by Punjab province in 1998. Pubjab represents about 70 percent of Pakistan's cropped area.

TABLE 14

Projected and actual cropping intensity in the IBIS

Source: Lieftinck Report, Vol. I, 1968; Agricultural Statistics of Pakistan, Government of Pakistan.

Increased cropping intensity has intensified pressure on surface water resources (cheap freshwater) and translated into a significant interference of upper and middle reaches water users into the operation of the irrigation distribution system. Therefore, farmers - particularly at the tail end - have installed many private tubewells to tap fresh groundwater resources for flexibility in water availability to meet their demand.

FUTURE WATER NEEDS AND AVAILABILITY

Future water needs for irrigation and non - irrigation sectors were computed for 2010. The irrigation sector includes water needs for agriculture, farm forestry, aquaculture, livestock and wetlands. The non - irrigation sector includes largely the domestic and industrial water needs. Present and future water needs and availability is presented in Table 15.

Present and future irrigation water needs

Net irrigation water requirement for crops in Pakistan is about 100 billion m³ for the year 2000. Rainfall was disregarded in estimating net irrigation water requirements, but it was assumed that a 10 percent contribution of rainfall in the basin is required for leaching to maintain the salt balance in the root - zone.

The agriculture growth rate targeted by the Ministry of Food, Agriculture and Livestock for the next decade (2000 - 2010) is 5 percent per annum. This would be achieved through increasing the cropped area by 0.5 percent per annum and raising productivity by 4.5 percent per annum for the next decade. The increase in cropped area of 0.5 percent per annum will be achieved by providing additional water to increase cropping intensity in irrigated area of the Indus basin. Increased availability of additional water will be mainly through saving water from existing losses; new storage reservoirs will not be available during the next decade, even if the construction started now. Instead there will be reduced available storage capacity in the basin due to continuous sedimentation of the Tarbela and Mangla reservoirs.

Increased productivity of 4.5 percent per annum would also require more reliable and adequate availability of water. Additional water requirement will be about 1 percent (1.26 billion m³) of existing canal supplies per annum. In addition, the annual loss of storage reservoir capacity is estimated as 0.30 billion m³ per annum.

Current mean annual canal diversions to the Indus command area total 126.4 billion m³. Additional canal supplies required to meet 5 percent growth in agriculture and to meet annual loss of live storage capacity of existing reservoirs due to sedimentation come to 1.56 MAF.

For the next decade, the additional irrigation water required to achieve 63 percent growth in agricultural production is 13.3 billion m³ (based on 1.26 billion m³ per annum), which is a considerable amount of water. Systematic efforts are needed to find new resources of water through improved management of water in the Indus basin and areas outside the basin. The future net irrigation water requirement for crops for the year 2010 is 113.3 billion m³ (Table 15).

The assumption was made that no additional storage will be available for the year 2010 compared to the year 2000. Construction of large storage reservoirs would require a period of 10 to 12 years. Water management will be the only workable option for the next decade.

The water budget presented in Table 15 seems quite different than budgets presented by other authors, including the Water Vision 2025 (PWP 2000). Actually the problem arises when experts entered into the estimation of gross water requirement, which is a function of efficiency and improved operational management of canals and efficient water use. Thus water budget must be seen in the context of the net water requirement. The budget made on the basis of gross water requirement supports the need for further water development and underestimates the potential for improved water management.

TABLE 15

Pakistan water requirement and availability, 2000 and 2010

*Based on 79, 60 and 75 percent of canal, watercourse and field application efficiencies.

**Based on 85, 65 and 80 percent of canal, watercourse and field application efficiencies.

Present and future non - irrigation water needs

The gross water requirement for non - irrigation needs was 7.3 billion m³ for the year 2000. This will increase to 10.7 billion m³ for the year 2010, based on a growth rate of 4 percent per annum for increased non - water needs due to a growth in population and coverage of domestic and industrial water supplies (PWP 2000). Details are provided in Table 15.

NATIONAL PLANS FOR CURRENT AND FUTURE WATER NEEDS

National plans and programmes

Shortfall in water use would increase from 12.4 billion m³ to 22.7 billion m³ in the next decade (2000 - 2010) even with an increase in overall irrigation efficiency of 44 percent compared to the current efficiency of 36 percent. Thus water resources development and management in the next decade will not make the country self - sufficient in irrigation and non - irrigation water needs. On the one - hand, intra - sectoral demand for additional water is increasing rapidly while on the other, opportunities for further development of water resources or maintaining their use to existing levels are diminishing faster than the expected pace. Thus the challenge for the next decade will be the effective implementation of a state of the art management cum development strategy.

Approach encompassing the development of additional reservoirs, integrated water management and use, introduction of water efficient techniques, containment of environmental degradation, institutional strengthening, capacity building and human resource development will have to be implemented (Planning Commission 2001).

Issues and objectives

The Planning Commission of Pakistan in its water sector strategy outlines water - related issues as:

• water shortages;
• seasonality in water availability and in - flexible canal irrigation system;
• inequities in water distribution;
• inadequate O&M funding and poor cost recovery;
• increased waterlogging and salinity hazard due to poor maintenance;
• excessive groundwater pumpage in certain regions and resulting in secondary salinization;
• effluent disposal and related environmental issues;
• absence of conducive environment required to introduce and implement water efficient irrigation techniques and practices;
• lack of private sector participation;
• deteriorating institutional capacity of key water sector institutions; and
• poor linkages among water, agriculture and rural development policies and strategies.

Objectives for the next decade (2000 - 2010) are to have sustainable development and integrated management of water resources and use, to meet the anticipated shortfall in water availability and need. This would be achieved through a comprehensive strategy of development cum management in the light of key issues identified for the sector. The specific objectives would address the key issues.

Planned options for meeting water shortages

Options outlined by the Planning Commission can be divided into two broad categories, the first including augmentation measures such as:

• constructing new reservoirs;
• raising the level of the Mangle dam;
• desilting the Tarbela dam;
• constructing carry - over dams;
• constructing small and medium size dams;
• harnessing hill - streams; and
• exploiting remaining groundwater potential.

Second category options include conservation and management measures:

• lining canals/watercourses with a priority to brackish groundwater areas;
• changes in cropping pattern to adjust for water availability; and the
• using high efficiency irrigation techniques.

Targets of the three year plan

Planning Commission has prepared a three - year plan considering the above - mentioned objectives and the options available. The physical targets of the three years programme of the water sector are:

• installing 660 SCARP tubewells;
• transition of 3 000 SCARP tubewells;
• rehabilitation/remodelling of 1 226 km of surface drains;
• constructing 728 km of new drains;
• building 301 km of flood embankments and 83 spurs;
• improving 15 000 watercourses; and
• precision land levelling of 45 000 ha.

THE VISION FOR 2010

Challenges

Agriculture sector

Research and development community is facing three challenges. The first challenge faced by irrigated agriculture is to raise production and productivity in favoured environments. Second, the challenge is to enhance production and productivity in less favoured environments such as the Balochistan valley, Rod - Kohi, the Barani lands and riverine areas. The third challenge faced by the country is that in the process of productivity enhancement the resources have to be upgraded rather degradation.

Population by the end of 2010 will be 171 million based on medium projections. A 30 percent population increase will require at least the same increase in food and fibre production to meet national requirements. Coupled with Pakistan's objective of increasing exports and reducing imports, it is more realistic to achieve 63 percent increase in agricultural production.

Targeted 63 percent increase in agricultural production would demand 13.3 percent increase in water availability. This additional water will come solely through savings of existing losses.

Domestic and industrial sectors

Urban and industrial sectors’ development community is facing three challenges. The first challenge faced by the urban and industrial sectors is to raise level of quality of service and reliability in water supply in large metropolitans and industrial states. Secondly, the challenge is to extend the access to piped water supply in small towns and rural areas and isolated settlements. Third challenge faced by the country is that in the process of provision of safe water supply to the urban areas and industrial states the water resources have to be upgraded rather degradation in terms of environmental concerns like management of sewage and industrial effluents. Rather the sources of sanitary and industrial effluents have to be blocked prior to entry into freshwater ways.

Population by the end of 2010 will be 171 million based on medium projections. The increase of 30 percent in population would require at least same level of increase in domestic water supply to meet the country's requirement. Coupled with country's objective of alleviating poverty and quality life, it is more realistic to achieve a level of 48 percent increase in access to safe water supply.

Targeted 48 percent increase in provision of safe water supply would demand 10.4 billion m³ of water for urban and industrial sectors. This additional water will come mainly through savings of existing losses.

Scenario

Vision 2010 is to increase agricultural contribution to GDP from Rs. 150 billion to Rs. 244 billion, a 63 percent increase. This would require increasing agricultural production by at least 50 percent with more emphasis on high value commodities such as milk, meat, vegetables and fruit to provide balanced nutrition to the population.

The driving issues which affect this scenario are population, economic growth, technological progress, social process, environmental concern, awareness and education and management levels.

RECOMMENDATIONS

Unresolved issues were identified which need to be addressed in the next decade. It is inappropriate to build recommendations for the irrigation subsector without considering the water sector as a whole (irrigation and non - irrigation sectors). Therefore, some tentative recommendations are:

• Comprehensive planning of the water sector coupled with integrated development and management of irrigated agriculture is essential to achieve self - reliance in agricultural production and sustainability of the resource base.
• Efficiency of water conveyance must be seen in the context of groundwater quality, as any loss of water in the brackish groundwater zone is not retrievable in terms of quality. Therefore, canal and watercourse lining programmes should be given priority in the brackish groundwater zone.
• Research/development of low - cost, effective linings for canals and watercourses should be strengthened.
• Local development of pressurised irrigation systems (including development of water and energy efficient pumping systems) should be encouraged. Private sector irrigation companies should be encouraged to provide services to farmers on a turnkey basis. Unemployed agricultural engineers should be trained to begin irrigation companies which can also provide domestic water supply and sanitation in urban areas.
• Productivity and sustainability research should address issues of water scarcity and inequity.
• Pilot projects in all major canal commands should be initiated to address issues of canal operational management, institutional reforms, productivity and sustainability.
• Farmers’ organizations at the distributary canal level should be given authority and financial autonomy. Agriculture extension must reposition activities to be more responsive to farmers' organizations. The irrigation system is managed on the basis of irrigation districts, whereas agriculture extension is organised by administrative boundaries. There is a need to organise irrigation and agriculture sectors both on the basis of irrigation districts in the Indus basin and valley basis in the mountainous areas.
• Provincial on - farm water management programmes should address both surface and groundwater issues. They must reorient their technical backstop support system to respond to farmers' organizations.
• Surface water resources especially the small dams used for provision of domestic water supply have to be increased to meet future needs. The losses of pipeline supply systems have to be decreased to provide additional water. Mass awareness programmes have to be initiated to motivate domestic and industrial water users’ in conservation of water.
• Emphasis should be given to recycling and re - use of water including wastewater management; and.
• Research on low - cost and low O&M treatment plants for sewage and industrial effluents should be initiated on an urgent basis.

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