As we enter the “Greenhouse” century of climate change, with its greater likelihood of extreme drought and floods, most countries are going from boom to bust. At the end of 20th century, the 150 years’ modern irrigation age is winding down.

On the economic front, irrigation expansion in many areas has reached the point of diminishing returns. Indus Basin is no exception and is more vulnerable to such global changes (climate and trade) because of its political ecology and narrow resource base. Until recently, the country, having 1400 M3 per capita water, was net food importer.

Many economists believe that water scarce countries can generate much more income from their limited water by using it in commercial and industrial enterprises and purchase their grain on the international market. This tidy logic is shaken, by the rapidly growing population who will be living in water scarce countries will follow this path. Water long left of the food security equation, may now be driving it.

As domestic competition for water spills into international competition for grain, it will be the poor of these food deficit nations that lose out. Thus irrigation water has to play a key role in meeting this challenge in the Indus Basin.

Pakistan is becoming water-poor country. In many areas, farmers are pumping ground water faster than nature is replenishing it, causing a steady drop in water table. Groundwater over-pumping could now be the single biggest threat to Indus agriculture. Over-tapped rivers are easy to see and the consequences fairly visible. Ground water overdraft, though hidden from view, is even more serious problem.

This coupled with global warming will further exacerbate the issue of water insecurity. The pace of dam-building is slowing down because of the resource constraints; environmental concerns and regional conflict. The surface waters though scarce, if managed properly, could only ensure the sustainability of agriculture. Now that water is increasingly scarce, however, raising productivity—getting more service, satisfaction and benefit out of every liter we remove from a river (Indus and its tributaries), lakes, mountain springs, or underground aquifer—is the key to meeting future needs of the country.

Thus water productivity—-getting more crops per drop— seems to be the agricultural frontier for the Indus Basin. The equity ratio in water distribution between head and middle farm is 5:1 and the efficacy of water is only 27 per cent. The over all irrigation efficiency of the system is only 26 per cent (conveyance efficiency: 75 per cent; delivery efficiency: 60 per cent and application efficiency: 75 per cent).

Surface water: Pakistan has the best irrigation system in the world. Indus and its tributaries supply surface water (93 million acre feet (MAF) at the farm gate through 40,000 mile long canals and 130,000 watercourses. Groundwater in the sweet zones is another important source of irrigation water (53 MAF annually). Of the total cropped area, 82 per cent is irrigated, 43 per cent is irrigated through canal, 37 per cent conjunctive use and 17 per cent is the share of tube wells.

Irrigation water is fugitive input and is subjected to over-withdrawals. There is a tendency of excessive irrigation through surface supplies and ground water is over drafted. The overall water conveyance efficiency is 45 per cent; 75 per cent from canal to outlet; and 60 per cent from outlet to farm gate. Thus, about 40 maf water is lost in the system (25 maf canal to outlet and 15 maf outlets to farm gate). Canal losses are attributed to deferred operation and maintenance. Farm gate losses are due to unlined watercourses and application inefficiencies. The pace of water course improvement is slow.

Groundwater: Groundwater is mined through public and private tube wells (493,000). Private farmers install most of the tube wells in sweet water zone. Public tube wells were installed in the Salinity Control and Reclamation Programme (SCARP) areas to pump out effluent discharge from waterlogged areas. These tube wells were of bigger capacity installed near canals to pump out ground water in these canals to lower water table.

It was often argued that SCARP tube wells, pumped out recharged sweet water from the canals, did not serve much purpose. However, in certain areas, these tube wells were able to lower the water table and valuable agriculture land was reclaimed. These SCARP tube wells have outlived their utility and government decided to privatize them in a phased manner. The size of the tube wells was large, thus farmers were unable to purchase. Private tube wells owners are overdrafting the aquifer due to which water table is going down.

Of the total surface irrigation water, 110 maf is diverted to canals, 70 per cent of the water is withdrawn in Kharif season and 30 per cent in the Rabi season. The canal withdrawals have been quite erratic in the past decade depending upon the snowmelt and rainfall during the monsoon. The provincial share in the Kharif withdrawals is 49 per cent, 47 per cent; and 4 per cent and Rabi withdrawals is 54 per cent, 43 per cent and 3 per cent in Punjab, Sindh, Balochistan and NWFP respectively in the year 1998-99. The availability of water as per canal withdrawals is 1.5 acre feet, 5 acre feet, 1.5 acre feet and one acre feet per cropped acre in Punjab, Sindh, Balochistan, and NWFP respectively. This shows that surface water is not enough to cater the consumptive needs of crops. Thus surface supplies are augmented with conjunctive use of tube well water at very high pump-age cost. The distribution of surface supplies must be cropping pattern oriented, and canal withdrawals may be measured and monitored through telemetry.

Escapage surface water: The escapage below Panjnad and Kotri is 22 maf and 35 maf annually. The average flow below Kotri is as high as 47 maf. The outflow is more in the month of July and August depending upon the volume of monsoon rainfall. The downflow below Panjnad goes to Indus, which can be further utilized, but escapage below Kotri (35 maf) is cause for concern. Some of the outflow (10 maf) is essential to check seawater intrusion and preservation of mangroves, and the rest needs to be conserved through construction of weirs in the Indus Delta and upstream dams.

Canal withdrawals: Canal withdrawals vary from month to month, depending upon the rainfall and decision of the Indus River System Authority. The average monthly flow is 4.7 maf with a coefficient variation (CV) as 32 percent in Punjab, 3.9 maf and CV as 51 per cent in Sindh, 0.055 maf and CV as 66 per cent in NWFP, and 0.26 maf and CV as 67 per cent in Balochistan. The monthly variations are quite high during the year in all the provinces. This indicates that canal withdrawals are quite unstable due to adhoc distribution of water and abrupt canal closures. The uncertain water supplies adversely affect the crop operations, and farmer decisions regarding crop choice.

Water balance: The total water is flowed from the river Indus and its tributaries is 139 maf annually (Table-1). The total consumptive use is 46 maf (consumptive use: 31 maf, municipal use 5 MAF and outflow to sea 10 maf) and the losses are 93 maf. The losses through the surface supplies are huge. Water losses are of two types, conveyance losses (68 MAF) and loss to the sea 25 maf after accounting for seawater intrusion. The conveyance losses include canal to watercourse head (26 maf) losses for watercourse head to outlet (35 maf) and application losses (12 maf).

Table 1: Water Balance for Indus Basin (1998-99)

The loss to the sea is colossal but mostly outflow is during the monsoon. Drought is already at the doorstep due to global warning. Parts of Sindh and Balochistan are already experiencing worst drought of the past 30 years. Therefore, it seems imperative to conserve water at all cost. There are 18 feasible dam sites where water can be stored. Government should make efforts to develop political consensus and resolve the issue of dam sites. Kalabagh Dam is one of the best-conceived projects.

Its construction has primary, secondary and tertiary benefits. The apprehension of NWFP merit attention but issues are not that serious, which cannot be addressed. The reservation of Sindh is ill-founded. Only land lying in the river bed area will feel the pinch. Most of the delta area/riverbed are state lands, which are occupied by the mighty liege.. The benefits of the Kalabagh Dam outweigh the negative impacts. There is a need for strong political will to resolve this vital issue and save the country from pauperism.

Besides surface water, the country is endowed with groundwater resources. The groundwater is pumped through scarp tubewells (9 maf) and private tubewells (44 maf). Of the total ground water (53 maf), 29 million consumptively used for crops and the rest are losses. The public tubewells were installed in late 50s and early 60s to control water logging and salinity. Private tubewells are a big source to augment surface supplies and consumptive use of water.

These tubewells are energized through electricity and diesel. The electric tubewells has been running on flat rate basis, which has caused over-exhaustion of the aquifer. This calls for a preventive regulation in order to preserve and manage ground water efficiently. Until recently, the government has switched to meter-system and electricity tariff is high, therefore, farmers are unable to bear high cost of water through electric pumps. In Balochistan, flat rate is continued in spite of the evidence of over-exhaustion of the aquifer.

In addition to above two sources of water, rainwater especially in monsoon is available. Annually about 30 maf of water is received. Of which 9 maf is consumptively used and rest are losses through seepage, run-off and outflow to sea. The rainfall is a natural gift and the country has to manage and conserve rainfall water especially in Rodkohi areas where large tracks of land can be brought under cultivation by proper diversion.

Overall water available is 222 maf (surface flows; 139 maf + tubewells, 53 MAF + rains, 30 MAF). Out of this total water availability 84 maf is consumptively used, 113 maf are losses and 25 maf outflows to the sea. This shows overall water balance of the Indus Basin. Future options: Pakistan has a tremendous potential for additional storage to replace lost capacity of existing dams, which is to the tune of 6 maf. In addition there are 18 feasible dam sites where additional storage can be built.

If the nation would not decide for such an important project of water, the country would experience water shortages. Thar, Cholistan and vast land in Balochistan have already faced a brunt of it. There is a need to conserve 25 MAF of water, presently out-flowing to the sea. As pointed out earlier, there are colossal losses through conveyance and canal watercourses. Therefore, lining of canals, raised section and watercourse improvement will save another 20 MAF of water.

The current allocation of the required operation and maintenance (O&M) cost is 87 per cent, 76percent, 41 per cent and 53 per cent in Punjab, Sindh, NWFP and Balochistan respectively. The recovery of O&M cost is 32 per cent, 22 per cent, 38 per cent and 12 per cent in Punjab, Sindh, NWFP and Balochistan respectively.

There is a large area of Rodkohi, Salaba and Riverine areas covering about 3.25 million hectares. This can be brought under cultivation through spat irrigation system, proper diversion and sinking of tubewells in Salaba and Riverine areas. The construction of check and delay action dams in Balochistan area will help address the water scarcity issue. In the rain fed areas, small dams, earthen ponds can be constructed to store run-off water in mountains. In NWFP, Punjab and Balochistan, 2 maf of water can be made available through such small irrigation schemes and dams.

Future water options: (a) conserve flow of water and/or (b) allocate water based on marginal productivity and/or (c) experience water shortage in the new millennium.

The future strategies that could be followed are:

Surface water: Additional storage to replace lost capacity of existing dams of 6 maf; additional storages to add new supplies to the Indus basin canal diversions- 14 maf; saving of conveyance losses in canals and watercourses- 20 maf; development of spate irrigation system in Rod-Kohi, Sailaba and Riverine areas covering 3.25 million hectares; small dams and earthen ponds to store run-off in mountainous and barani areas of NWFP, Punjab and Balochistan - 2 maf.

Ground-water: existing contribution of groundwater - 40 maf; reduction in groundwater pumping due to high energy prices - 10 maf; sustained pumping up to 55 maf through energy-efficient pumping systems.

Future strategies: crash programme for cleaning of raised section of canals, watercourses, minors and distributaries;

* remodelling of outlets for uniform distribution of water;

* crop independent water rates (abiyana) may be charged on gross farm area in order to recover the O&M cost and gradually moving to a volume based pricing;

* minimize element of rent seeking by irrigation personnel;

* participatory water management through provincial irrigation development authorities may be encouraged at secondary and tertiary canal level;

* investment in surface supplies to improve remaining 74,000 watercourses. The current pace is slow;

* groundwater pumpage may be regulated through licenses in order to check over draft of the aquifer;

* consensus on new dam sites is imperative to ensure water supplies;

* increase cropping intensity within Riverine area by better water management at system level.

Options for improving irrigation water productivity:

* technical (land levelling, surge irrigation, high irrigation efficiency technologies (HIET)-drip and sprinkler);

* managerial (better scheduling, improve canal operations, water application at critical period, water conservation tillage, better O&M and drainage reuse);

* institutional (establishing of Water Users Associations for managing the system, reduction of water subsidies and introducing conservation-oriented pricing, water markets, private sector initiative for developing HIET); and * agronomic (selection of crop varieties with high yield per liter of transpired water, inter-cropping, better matching and sequencing crops, drought tolerant crops and evolution of water-efficient crop varieties).