The impact of drought and decline in groundwater levels on the spread of sand dunes in the plain in Iran

Abstract

Sand dunes are one of the types of Iran desert regions, which are occupying a significant extension of deserts area of Iran. The study area is part of Yazd-Ardakan with an area of 34,028.8 hectares in Yazd province. The aim of this study is to evaluate the impact of the decline in groundwater levels and increasing drought on spreading sand dunes. To map land use during the three decades in 1986, 1994, 2002 and 2016 were extracted from Landsat satellite images. Using different processes and methods of artificial neural networks, ARTMAP fuzzy is obtained land use map for mentioned years. To investigate the relationship of these changes, decline in groundwater level of the water table level statistics of 23 wells in 1982, 1995, 2009 and 2016 using of ArcGIS software to kriging method interpolated and rate of water loss were calculated. Also, drought index SPI by software DIP and method of interpolation inverse distance were estimated during this time interval and were compared to the number of days of dust per year. The area of sand dunes has reached from 15% in 1986 to 33% in 2016. In 1982, half of the area has been groundwater at a depth of 30–50 m from ground level in the event that there had been not from 2009 other water at this depth, and in the years 2009 and 2016, 60% of the area is located at a depth of 50–70 m and 10% at depths greater than 100 m, and the maximum of drought index value in the area is − 1.19 and its minimum is − 0.66. The southern part had an area of drop in ground water and growth of sand dunes and also drought index value is greater.