Investigation of the Effects of Climate Change and Meteorological Drought on Groundwater Drought in Wet and Semi-humid Areas (Case Study: Talesh plain)

As a result of global warming, the climate will change in terms of average temperature and rainfall, with groundwater being one of the factors impacted. Consequently, the influence of climatic elements such as temperature and precipitation on groundwater drought values in the Talesh plain was investigated.

Initially, the LARS-WG model was used to calculate climate change values. Subsequently, using the Mann-Kendall test and the Pearson correlation of these two indices, the values of meteorological and groundwater drought indices were produced, as well as a study of the trend of these indices.

The findings of the annual changes in rainfall and temperature throughout the following period (2020–2040) reveal that precipitation of 9, 1.75, and 0.75% and the temperature of those have grown by 1.05, 1.32, and 1.81 °C under the scenarios of RCP2.6, RCP4.5, and RCP8.5, respectively. Also, in the basic period, the declined average level of the aquifer in this 15-year period was 0.86 m. On the other hand, the impacts of climate change on decreasing groundwater level over the future period compared to the base period under the above scenarios indicated that the aquifer by 2.07, 2.21, and 2.34 m, respectively. Although it indicates that the rainfall has risen in the area, unrestricted drain from the aquifer has resulted in a decline in groundwater. The study also reveals that meteorological drought occurred in the basic era at a rate of 49.66, 50.35, and 41.73% at the scales of 12, 24, and 48 months, respectively. Therefore, in order to mitigate the severity of the drought and avoid excessive groundwater aquifer fall in this plain, required actions are essential to decrease water consumption by water resources managers and executive bodies under the present circumstances.