Investigating the flow regime changes in Musian Plain and assessing its impact on the region dynamic change

There are several stream channels in Musian Plain which change surface flow regularly as well as cause great damages to the basin’s residents. In order to prevent or reduce the risk of flow regime changes, surface flow dispersion on the permeable alluvial fans is controlled by implementation of the biological and structural practices. Therefore, in this study, two objectives are followed: first, comparison of flow regime changes of Musian Plain on the flood spreading and adjacent areas (control area), where there have been no structural and biological practices; and then, evaluation of these changes impacts in the area’s dynamics and land use. For this purpose, satellite images of Landsat 7 and 8, TM, ETM, and ETM sensors in 1998, 2002 and 2014 were used. The relationships between morphological parameters in the control and spreading areas, before and after flood spreading were obtained. Then, the effects of flow regime changes, as well as, land use dynamics were assessed. Results showed that the structural and biological practices are the main factors which change the flow patterns in the study area. The relationships between morphological parameters before and after practices showed the changes of drainage density index from 1.5 to 1.09 (km/km2), as well as the bifurcation ratio from 3.11 to 11.45; respectively. It indicates the stable flow regime in flood spreading practices rather than the control area. Controling and reducing the vlume of flood, means 9.1 MCM annual recharge , decreasing trend of average permeability in spreading areas, compare to basic permeability as much as 13.57 and 17.95 (cm.h-1), respectively,reduction of sand particle and increasing of clay and silt in flood spreading area compared to the control area, development of cultivation area up to 2410 (ha), rising of forage production by 109 (kg/ha-1), the increasing of trees and wells as much as 254181 and 62 respectively. Also, floodwater spreading affects on the pattern of flow dynamic and land use of the Musian area.