The role of the Bandsar in flood control, infiltration and recharge of water resources

The need to provide food for farms and the lack of roads and cars for transportation in the past led to the invention and innovation of a check dam called Bandar. Bandsar as a watershed check dam is the most important rain fed lands in semi-arid climates (such as South Khorasan Province). This structure turns threats (season flooding) into opportunities. Bandsar is a traditional structure with several main goals such as: cultivation, flood mitigation and erosion control, water harvesting and infiltration, flood water spreading and groundwater recharge. Accordingly, in this research detected 435 Bandsar with 205 thousand cubic meter by using satellite images and  field measurement , finally investigating the role of Bandsar in the floods hydrographic characteristics, water harvesting and infiltration of water resources in Seyujan-Tejk plain of Khosf city in South Khorasan province. For this goal, using climate data (1982-2020 period), topography map, cover plant, land use and features and capabilities of ArcGIS10.4 and HMS software.  The results showed that Bandsars control 100% of the runoff from rainfall up to a 10-year return period and Bandsar output relative input hydrograph has 2 sharp characteristics; 1- lag to peak and 2- peak attenuation and 76.75% of the water harvesting is infiltration and recharge groundwater recourses.