System Dynamic Modeling of Scenarios for the Protection of Groundwater Resources in Drought Conditions in South Khorasan Province, Iran

The purpose of this research is to model scenarios for the protection of underground water resources in South Khorasan province in drought conditions.

In this regard, this problem was followed using the system dynamics approach and the behavior of the reference variable "Volume of underground water resources of South Khorasan Province" was simulated against different scenarios during the years 2013 to 2014 through the use of Vensim software. The required information was collected by referring to relevant organizations such as South Khorasan Regional Water Organization, South Khorasan Agricultural Jihad Organization and Iran Statistics Center, and the input data of the model was called into the model in the form of an Excel file.

The results of the research showed that applying the control scenario of water resources exploitation in normal drought conditions and drought with low intensity is useful, but applying this scenario in drought conditions of more than 20% will have negative effects on the economic indicators of the agricultural sector. Also, the fourth scenario of the cultivation pattern (emphasis on strategic crops) along with the fifth scenario of the cultivation pattern (drought-resistant crops) have brought the least pressure on underground water resources. Nevertheless, considering that cultivation pattern No. 4 has created the least added value, it cannot be an efficient pattern.

According to the results of the research, if the severity of droughts increases in the coming years, but the current agricultural conditions of South Khorasan province continue in terms of cropping patterns, droughts will not have an effect on economic indicators, because in these conditions, farmers By breaking the ground and extracting more from underground water sources, they will compensate for the lack of rainfall and will show the negative effects of drought on the stock of underground water resources. Considering the effect of the cultivation pattern on underground water resources and economic indicators, it is necessary to think of measures to change the cultivation pattern.