aplication of optimal control model in grandwater extraction (case study: ajabshir plain)

abstract the use of water sources has increased due to extend of agricultural activity for answering food needs of increasing population. while because of exploitation and consumption of water, the use of this restricted resource is not appropriate. consequently in many districts of country the head level of ground water aquifers have been fallen and water level is negative. so, application of a proper management program in optimal use of these resources seems to be necessary. with respect to the effects of depletion of ground water store through the time, the time is an important variable in solving of optimization problems for these resources. thus, the application of dynamic models such as optimal control for these cases because of focusing on time is essential. models are solved in order to maximize the social net benefit subject to stability of aquifer. in this study, optimal control model is applied for ajabshir plain where is an important agricultural area in azarbayjan-e- sharghi. this plain has been faced with limitation and shortage of water supplies and negative water level in aquifer. the optimal extraction path was determined by execution of the optimal control model in this ground water aquifer. the results show that ground water aquifer built- up and reach the optimal steady state in 36 years. thus ground water extraction would decrease besides another resource (backstop) would be applied to secure demand of farmers during this period of. subsequently, regard of determined extraction would result in stability of ground water aquifer and on the other hand, it would cause the stability of agricultural activities as well as increase of farmer's revenue.