Investigation effect of floodwater spreading on vegetation and soil (Case study: Floodwater spreading of Miankooh, Yazd)

Using of flood to supply plant water requirement for its growing and decreasing of flood damages is possible by many different methods. By using of water spreading systems, seasonal flood in susceptible land will be spread with different effects on groundwater, plant cover and soil on these lands. In order to measure the effect of water spreading system on changes of vegetation, soil salinity and organic carbon in Miankooh floodwater spreading area, 40 random plots of 2 sq. meter were taken in floodwater spreading area and 20 points were selected outside the floodwater spreading(control areas) and vegetation were changes measured. Meanwhile, to investigate soil salinity and organic carbon changes, 8 profiles were taken from four depths ranges including 0-10, 10-20, 20-30, 40-60 cm in the area affected by flood and sediment and some points were selected in outside floodwater spreading(control areas). The statistical results indicated that floodwater spreading have significant effects on vegetation cover and salinity reduction (in depth=0 to 10cm) while no significant effect on soil organic carbon. Generally floodwater spreading from one hand can reduce soil salinity and consequently increase amount of plant cover in arid and semi-arid regions but on the other hand, high volume of flood and deposition of sediments, reduce the efficiency of water spreading over the time.