Study of the Development of Greenhouse Estates and Its Impact on Groundwater Levels of Ajichay Basin Aquifers Using SWAT Model

Greenhouse crops production is one of the major strategies for managing optimum use of water resources due to creating desirable conditions for plant growth over the year, multiplying production and reducing water usage. In the present study, two scenarios were adopted according to the current policies for the development of greenhouse towns in Iran and an ideal scenario (third scenario) was also considered for the development of greenhouse towns. The soil and water assessment tool (SWAT) model was used to evaluate the impacts of the implementation of development scenarios of greenhouse towns. Statistical indicators showed very high accuracy in simulating hydrometric stations of study area, as for Akhola hydrometric station (basin outlet), the statistics of correlation factor, Nash-Sutcliffe efficiency (NSE), and root mean squared error (RMSE) in the calibration period were 0.77, 0.62, and 6.21 m3 s-1, respectively, and in the validation period were 0.83, 0.66, and 3.09 m3 s-1, respectively. The development of greenhouse towns with an area of ​​1875 ha in Ajichay basin for the first and second scenarios resulted in an average drop of 11.68 m and 4.41 m in the groundwater level of the aquifers in Ajichay basin compared to the initial conditions. Simulation of the third scenario increases the groundwater level of aquifers of Tabriz, Azarshahr, Damaneh Shomali Sahand, Bostanabad, Duzduzan, Mehraban, Bilverdi, Asbforoshan and Sarab by 4.12, 2.73, 1.45, 8.88, 10.93, 2.90, 4.79, 2.99, and 3.31 m, respectively, and also has compensated a large amount of their negative balance. The results revealed that the development of greenhouse towns using new water resources can increase agricultural crop production and also intensify the downward trend in groundwater levels.