The research questions

• The broad scale exploitation of groundwater through large capacity private tubewells especially those installed in the central regions of doabs (land units lying between two major rivers) has serious consequences as the quality of pumped groundwater deteriorates due to upcoming of saline groundwater.
• Is it possible to replace conventional bores with improved skimming wells (low discharge shallow tubewells) and better management strategies to mitigate mixing and Stalinization of fresh groundwater?
• Will the introduction of skimming well technology to sustain groundwater irrigation in these areas, bring farmers and productive irrigation back to abandoned areas?

Objectives

• To identify and test promising skimming well technologies in shallow groundwater aquifers to control saline groundwater upcoming as a consequence of pumping.
• To prepare and implement guidelines for irrigation scheduling with skimmed groundwater applied by low cost pressurized irrigation systems to manage root zone salinity.
• To encourage and support in-country manufacturers to develop low cost pressurized irrigation application systems adaptable within the local setting of Pakistan.

Methods

• The existing design and operational strategies of the skimming wells in the Chaj doab area of Pakistani Punjab were evaluated Different components of this project adopted different methods.
• GIS based temporal and spatial analyses of deep groundwater quality were done to locate potential locations for installation of skimming wells.
• PRA techniques were applied to gather information regarding the performance, practices and constraints with farmers' skimming wells and irrigation practices.
• Detailed field tests were carried out to study the efficiency of skimming wells with varying discharges and bore depths to determine appropriate number of strainers and appropriate operational regimes. Detailed MODFLOW modeling was undertaken to extrapolate site tests.
• Pressurised irrigation technology (mainly sprinkler irrigation) and alternative surface irrigation methods were evaluated in conjunction with these tests.
• Transient modeling approaches were used to study the groundwater behavior under different skimming well operational strategies. Soil-Water-Crop modeling was done to study the long-term effects of skimmed groundwater use on salinity and yields of different crops (SWAP model). This modeling was also used to develop appropriate irrigation schedules for using skimmed groundwater.

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