Remote sensing techniques for estimation of potential and actual evapotranspiration offer new approaches for improved spatial and temporal estimation or evapotranspiration. The use of improved spatial and temporal assessment of rainfall and evapotranspiration has greatly assisted in providing accurate inputs for the groundwater model.
A regional groundwater and solute transport model for Rechna Doab in Punjab Pakistan was developed for PID. The model is a significant enhancement over previous models carried out in Pakistan which were based on seasonal time steps covering Kharif and Rabi seasons. The Rechna Doab model was developed at monthly time steps which offer PID an opportunity to better understand the temporal and spatial surface water and groundwater dynamics. Moreover, the regional model also provides opportunity to create sub-models at a finer spatial scale for detailed studies of canal and groundwater interaction. Examples of these are the LCC East and Rakh Branch sub-models.
A socio-economic study was also undertaken for LCC East (Lower Chenab Canal Command). The results of the water user scenario analyses, resulting from econometric as well as hydrological modelling approaches, will assist PIDA and Farmer Organisations for implementing more equitable, economically efficient and improved water quality options in the study areas.
A major concern for Punjab Irrigation Department (PID) is the lack of capacity within the department to monitor, model and manage groundwater resources to achieve sustainability of the resource over the long run. There is a significant concern of groundwater levels being depleted in the major irrigation areas where cropping intensities have increased from the design levels of 67% to over 150% and a concomitant increase in tubewells and groundwater withdrawals. The increase in tubewells to over 1 million tubewells in Punjab alone is cause for concern as depletion of groundwater also increases the risk of salinisation of fresh groundwater resources which many smallholder farmers depend on for their livelihoods. Thus one of the most important goals was to provide training to PID staff to improve knowledge of how the Rechna Doab model was developed, construction of the conceptual model, usefulness of monitoring data for model calibration and verification, water balance analysis and scenario analysis. The training also covered introduction to MODFLOW and MT3D and various example models to help trainees understand how models can be applied to evaluate demands on the groundwater resources.
A unique addition to the modelling training program was to provide training in remote sensing and the use of GIS for estimating spatial distribution of crop water use for various canal commands in Rechna Doab. The trainees were introduced to NDVI and crop spatial mapping analysis techniques to identify various crops grown in Rabi and Kharif. Additionally training was provided in the use of a Google API tool for estimating crop water use for various locations within the study area.
In groundwater irrigated agricultural areas of Punjab Province, Pakistan, salinity intrusion due to over extraction of groundwater and deepening watertable adversely impacts crop yield and agricultural production. Such salinity effects are significant at distributaries towards tail end of canal systems. The purpose of this SRA, i.e. training program, has been to disseminate the hydrological and econometric modelling results of a completed ACIAR project in Punjab, Pakistan (LWR/2005/144) on how to redistribute conjunctive use of surface and groundwater to minimize the salinity effects on crop yields and redistribute the water sources in an equitable manner along the distributaries in the Lower-Chenab Cannel (LLC) irrigation system.
The SRA for groundwater modelling, remote sensing and socioeconomics included training sessions and field visits conducted at two occasions in Pakistan in August 2015 and April 2016. One of the objectives of the SRA was to enhance capacity of PID, PIDA, and postgraduate students at UAF, and UAAR in groundwater modelling, remote sensing and econometric modelling.
The SRA activities also included additional focussed scenario runs and providing review for policy support materials. The scenarios undertaken included: increased pumping and drought impacts of various durations. Additionally a simplified TMR (Telescopic Mesh Refinement) model of the Rakh Branch was extracted from the regional Rechna Doab model as a training exercise and for future detailed studies.
The framework for the groundwater status report is provided as a starting point for consideration. The report can be tailored to meet the needs of a particular region, the aim being to propose a framework for a Groundwater Status Report that would be provided to management annually to enhance planning and decision making within the Department.
Draft papers for the Rechna Doab model and additional scenario modelling, and remote sensing applications and analysis is under preparation and abstracts are included in the appendix. A draft paper on the impacts of irrigation water user allocations on water quality and crop productivity has been completed and is attached.
Two reports were prepared by PID on awareness raising and capacity building of FO’s and farmers on groundwater management issues for Kamalia Distributary and Khikhi Distributary have been completed and form separate reports.
|Place of Publication||Canberra, ACT|
|Publisher||Australian Centre for International Agricultural Research (ACIAR)|
|Commissioning body||Australian Centre for International Agricultural Research (ACIAR)|
|Number of pages||88|
|Publication status||Published - 2017|