A research study submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development

Research Studies Project Report (M. Eng.) - Asian Institute of Technology, 1993

Pakistan experienced an unprecedented development of large irrigation resource system in the twentieth century and ground water resource of irrigation in the last 28 years by the Public and Private sector. Tubewell (T/well) development raises concerns over the environmental sustainability of the present agricultural production base. This study introduced the concept of crop based irrigation water demand and water use under farmers perceptions at production of crop marginal yield value. The interactions between the marginal yield value, the total water demand, the farmers perceptions for water application through canal supplies, groundwater extraction by T/well, and natural blessing of rainfall as a part of irrigation demand. Also the relationship between groundwater demand, conveyance losses, water quality, alternative water supplies and marginal water demand were considered. Data collected from 4L distributary sample of T/well owners and non-owners allowed comparison between the observed crop water demand and current withdrawal rates and analysis of factors constraining groundwater use. Availability of water at farm gate and quality of water and marginal water cost influenced cropping patterns. A Linear and Quadratic Regression Model were used to determine the variance in irrigation supplies and to determine the correlation between water applied to 34 sample wheat fields during Rabi (November-April), 1991-92 and marginal yield response to know the best yield factors between overall wheat field samples and sampled irrigated by the T/well extractions at lowest marginal costs and also with LASER levelled fields. Economical range for marginal fit quality groundwater irrigation was derived comparing LASER Land levelled wheat fields irrigation with seasonal output per hectare production value and focussed on recommendations for development technology in irrigation management.