Sand drift potential impacts within desert railway corridors: a case study of the Sarakhs-Mashhad railway line

Abstract

Railways play a key role in the connection between urban and rural areas and enhance the economic sectors of many countries. However, little is known about wind regimes within the railway corridors, particularly in developing countries. The main aim of this research is to identify and analyze wind regimes and sand drift potential (DP) within the Sarakhs-Mashhad railway corridor based on 3-h wind speed data collected during the last two decades (1996–2016). Our results showed that the highest frequency of winds in the three monitored stations was from the northwest (NW) and north (N) for the Sarakhs (NW=21.5%, N=9.3%) and Torbat-e Jam (N=16%, NW=28.4%), and from the south (S) and east (E) for the Mashhad (S=13.49%, E=13.3%). Monthly analysis of wind regime showed that the mean frequency of calm winds increased from 26% in Torbat-e Jam to 46% in Sarakhs. Annual assessment of the sand rose graph showed that Torbat-e Jam registered the highest DP values (DP= 336, RDP= 211) and the Mashhad area the lowest (DP= 71, RDP= 22). Looking at the complete Sarakhs-Mashhad railway line corridor, summer months (particularly July) recorded the highest frequency of sand drift potential, while the autumn season recorded the lowest values. Some railway stations such as Sarakhs, Gonbadli, and Robate Sharif in the vicinity of Sarakhs Erg have the greatest threats of damage by sand movement. We recommend an increase in the stabilizing activities using biological methods of native plant species, especially planting perpendicularly to the erosive prevailing wind direction (north–northwest).