Optimising Canal and Groundwater Management to Assist Water User Associations in Maximising Crop Production and Managing Salinisation in Australia and Pakistan (2008 -2015)

Funding

ACIAR, $1,219,708

Investigators/ Researchers

Professor John Blackwell, Dr Jay Punthakey, (ILWS adjunct) and  Dr Richard Culas with partners in Pakistan Punjab Irrigation Department and UAAR-PMAS Arid Agricultural University

Description

The Rechna Doab, which covers an area of 2.98 million ha

of irrigated land, is the interfluvial sedimentary basin of the Chenab and Ravi rivers, comprising part of the Indus River basin irrigation system in Pakistan.  Since the 1980s, pumping of groundwater for supplementary irrigation has reduced groundwater levels, and leakage from rivers and canals to groundwater has become the predominant form of surface water and groundwater interaction. Groundwater pumped from tubewells in the doab has played a vital role in increasing the intensity of agriculture in the Rechna Doab and contributed to improving food security.

Right:A distributary in Rechna Doab   Photo Dr JF.Punthakey

For this project a regional flow and solute transport model was developed which assessed availability of groundwater resources and interaction of surface and groundwater in the Rechna Doab. Spatial and temporal assessment of groundwater use, availability of surface water supplies, and climatic variability were modelled to assess the quantity and quality of groundwater resources.

The study found that the major components of the water balance are recharge from rainfall, river leakage, canal leakage and irrigation recharge which accounts for 93 percent of inputs to the system.

Four scenarios were undertaken from 2014 to 2030 to assess aquifer status and availability of groundwater for irrigation and to meet planning requirements for PID. A comparison of the simulated scenarios showed that if groundwater pumping was reduced by 10 percent and surface water availability was increased by 10 percent then an estimated total water savings of 900 GL/yr is possible.

The study found that improved controls on pumping will achieve greater water savings. Thus PID will need to focus effort on significantly enhancing the level of groundwater management.

Based on the calibration period from 2008-2013, the researchers recommended that:

• Pumping from Rechna Doab should be managed around 11,000 ± 1000 GL/yr depending on the need for pumping in response to drought and or lack of surface water supplies
• When surface water supplies are plentiful pumping levels should be decreased so that the groundwater system gets recharged with freshwater
• Additionally, PID may want to consider establishing managed aquifer recharge (MAR) schemes in specific suitable areas of Rechna Doab where water tables are sufficiently deep and where soil conditions are favourable for establishing MAR schemes.

Since 2008 PID has implemented a systematic monitoring program of water levels and water quality parameters from several hundred piezometers and tubewells.

The researchers recommended that, to make a difference in management of groundwater:

• This monitoring program should be rationalised and key bores need to be instrumented with loggers that monitor water levels and salinity
• In addition targeted metering of key tubewells in Rechna Doab need to be implemented so that there is a sound basis for future improvement of the model and management of water resources of the doab.

The researchers identified that, when surface water supplies are unequally distributed resulting in less water for tailenders, farmers tend to increase reliance on groundwater despite the fact that the water quality may not be suitable. There was an urgent need for improved access to surface water supplies for mid and tailenders, in combination with advice to farmers on use of groundwater for irrigation and improved monitoring and governance of groundwater.

Other recommendations were made for improved governance of groundwater and to assist PID in establishing a groundwater group which will be responsible for improved sustainability of groundwater in the four major doabs in Punjab.

Right: Irrigated Rice cultivation in Rechna Doab  Photo Dr JF.Punthakey

Outputs

Optimising Canal and Groundwater Management to Improve Crop Production and Manage Salinisation for Rechna Doab Groundwater Modelling for Rechna Doab, Pakistan – Interim Report, Ecoseal, UAAR, CSU & ACIAR

Outcomes

The study has improved understanding of the sustainability of groundwater usage in Rechna Doab and provided the Punjab Irrigation Department with tools to improve the management of surface and groundwater in the doab. It has supported the Punjab Irrigation Department in the implementation of more equitable, economically efficient and sustainable canal and groundwater management options for Rechna Doab. This project has led to a second, larger project in Pakistan, Improving groundwater management to enhance agriculture and farming livelihoods in Pakistan. (2016-2020) Finlayson, M., Punthakey, J., Allan, C., Mitchell, M. ACIAR & CSU ($100,000), Total value of the project $2,15M  Project details

April 2017