A simulation/optimization model for groundwater resources management in the Afram Plains area, Ghana

A groundwater flow simulation model was developed using available hydrogeo logical data to A groundwater flow simulation model was developed using available hydrogeological data to describe groundwater flow in the Afram Plains area. A nonlinear optimization model was then developed and solved for the management of groundwater resources to meet irrigation and household needs. The objective was to maximize groundwater extraction for irrigation activities from the shallow aquifers of the southern Voltaian Sedimentary Basin that underly the area This would improve food security, raise the standard of living and ultimately alleviate poverty in the Afram Plains. The calibrated flow model is in tandem with the general hydrochemical evolution of groundwater in the area and fits the observed data with about a 98% degree of confidence. Groundwater resources may not be the limiting factor in the development of irrigated agriculture. Groundwater has tremendous potential to meet current and future irrigation needs. It was determined from this study that profit from maize irrigation in the Afram Plains area could rise from US$301, 000 in 2007 to over US$3.5 million by the end of the last management period (2013) as irrigation practice is improved, and the economic strength to increase the acreage for irrigation improves. Even with these margins of profit, the drawdown constraint was not reached in any of the management periods. It is expected that rechargefrom the irrigation water would reclaim the lost hydraulic head. The single significant constraint was the amount of land area that could be developed for irrigation in the area. The profit obtained per unit cubic meter of water used also improved over the same management period.