Three alluvial fan surfaces (relict, old and young) were selected
within the study area. Since there is only one catchment upstream of
studied fans, the source areas of all fans are same in terms of lithology.
These are located in the northeastern part of Rivand village in west of
Sabzevar, Northeast Iran. The upstream catchment of these alluvial
fans drains an area of 49.57 km2. The areas of relict, old and young
fans are respectively 4.26, 26.86 and 18.16 km2. Based on the Sabzevar
synoptic station near the studied alluvial fans, the mean annual precipitation, temperature and relative humidity (during 1977-2006 period)
are 206.6 mm, 18.36 °C and 40%, respectively.