Assessment the effects of flood spreading on the variation of rangelands vegetation cover (In Mayhem watershed in Ghorveh, Kurdistan)

Flood water spreading projections have been done with many objectives. One of theseobjectives is increasing vegetation cover. Flood water spreading leads to the increasing of soil moisture and as a result increasing forage production. In this study the effects of flood spreading are evaluated. This assessment is done in aquifer of Mayhem district of Ghorveh state. In each rainfall that results into flood, 6 areas are flooded and 2 areas are not flooded. Therefore, 6 areas considered as the flood water spreading and 2 areas considered as the control site. The samplings of vegetation properties were performed in these eight areas. For this purpose, in each district, 5 transects each with a length of 100 m with 10 m interval from each other were situated and along each transect, 10 quadrates with an area of 1m2 were established. In each area, the characteristics of canopy cover percentage, forage production and species density were recorded. Analysis of data was performed using of un-paired T-test. Obtained results from Ttest indicated that there is significant difference between canopy cover percentage (p≤ 0/1) andforage production (p≤ 0/05) while no significant difference was observed for species density in flooded and non-flooded areas. The results showed that the canopy cover increased from 41/91 percent in the control site to 62/18 percent in the flood spreading area. The forage production increased from 467/17 kg/ha in the control site to 632/17 kg/ha in the flood spreading area. Also the species density increased from 1/18 in the control site to 1/59 in the flood spreading area.Some of the plant species that are in the III classes from palatability aspect, decreased in the flood spreading area rather than control site.