INDH is located at the tail end of the Indus river system, and is vulnerable to frequent water shortages, which remain moderate to severe.

The factors that undermine conservation of water in the provincial irrigation system include interprovincial discord over water distribution and bad governance.

Another major factor is the unlined irrigation network. The Sindh government has lately started paying heed to it. Apart from foreign-funded lining projects, a provincial-level initiative is also under way to ensure lining of channels and canals.

Irrigation and water experts agree that climate change makes it all the more important that the lining of irrigation network should be given preference to ensure optimal use of available water resources.

Lining certainly needs to be linked with other advanced methods of cultivation like laser land levelling. A piece of farmland levelled with laser techniques gets uniform distribution of irrigation water, improving per-acre productivity.

Sindh`s 80 per cent of groundwater is brackish. The aquifer of shallow water table, which is fit for drinking, is scattered across the province and therefore should be used wisely, says Dr Bukhshal Lashari, a water expert at the Mehran University of Engineering and Technology (MUET).

Ahmed Zeeshan Bhatti, a water researcher in Pakistan Council of Research in Water Resources, Islamabad, says, `Lining should be a matter of life and death for Sindh in view of report of International Waterlogging and Salinity Research Institute. The report says that 60pc of the province`s irrigated area faces threat of waterlogging.

If remedial measures are not taken immediately, Sindh would have to bear more waterlogged land in the next five years or so, he says. Seepage in major canalsis always massive and it always occurs at a particular location around the canal whereas seepage or losses at field level remain higher but scattered.

`Generally, 60pc of water losses take place right from the canal head to water-course level and 40pc of water is used actually by a crop,` he says.

Sindh`s farmland is mostly fed by two major perennial irrigation canals, ie Rohri and Nara, which emanate from the left side of colonial era`s Sukkur barrage, considered lifeline for Sindh`s farm sector. The 350kmlong Nara and 330km-long Rohri canal irrigate large swatches of land. The left bank of the Indus river isconsidered breadbasket of Sindh`s farm sector where crops like cotton, sugarcane and wheat are grown or horticulture activity is seen on a large scale.

Cumulatively, these canals irrigate around 5.3 million acres of land and therefore get preference in terms of water provision by irrigation authorities as compared to remaining 12 canals of all three barrages of Sindh.

Both these canals are unlined. It indeed requires a huge expenditure if these canals are to be lined from head to tail.

The Sindh government has given some thought tolining. It was in 2015 when a 10km strip of Rohri canal, considered mini-Indus and passing through Benazirabad district, was lined at a cost of Rs3.1bn.

The lining of another 20km strip is in the pipeline at a total cost of Rs14bn.

Similarly, Jamrao`s west branch a system that takes off from main Nara canal has been recently lined in Mirpurkhas district. Reports indicate it has improved agriculture land around the canal that had become saline.

Dr Lashari of the MUET observes that seepage in the irrigation system has remained uncontrollable.

He says the injudicious distribution of water has remained a menace, as landowners in the upper Sindh use water first while tail-end growers end up facing severe shortage. Salinity in such tail-end regions is always bound to increase owing to capillary action, he says.

To make matters worse, the drainage system that is vital to control waterlogging exists in 40pc to 50pc of the command area. `The lining of watercourses and distributaries is a must for bringing more area under cultivation or improving soil fertility.

Around eight years ago, the Water and Power Development Authority (Wapda) initiated a feasibility study of lining of three major canals of Sindh, including Rice, Dadu and Rohri, but the plan has yet to materialise.

Currently, lining of a considerable number of watercourses is under way in Sindh under a foreign-funded programme. In addition, the provincial government, through its annual development programme, plans to spend Rs15bn in a block allocation to line 20km strip of Rohri canal. Feasibility study of Nusrat branch`s lining was also being carried out, official sources says.

A federal funded-programme to line distributaries and minors in Sindh has been halted in the wake of the 18th constitutional amendment under which irrigation department was devolved to provinces. •