| چکیده انگلیسی مقاله |
Spatiotemporal variations of regional watershed health in the Shazand Watershed, Central Iran, were studied based on the momentous concept of the Vigor-Organization-Resilience (VOR) framework. Toward this, indicators of vigor (V), organization (O), and resilience (R) were established by characterizing 14 environmental data series of 1986, 1998, 2008, and 2014 for the study watershed. Various criteria of Normalized Difference Vegetation Index (NDVI), soil degradation intensity, runoff coefficient, and slope steepness were used to calculate the watershed vigor indicator. To calculate the organization indicator, the vegetation cover situation and replacement of NDVI centroid, landscape diversity index, erosion uniformity, runoff uniformity, and the ratio of contributing area in runoff generation to the total area where applied. In addition, the landscape richness index, the slope of erosion variations, the slope of discharge variations, the slope of NDVI variations, and stream density were accomplished to assess resilience indicators. Thence, a composite watershed health index defined by the geometric mean of V, O, and R indicators was introduced. The necessary prerequisites such as autocorrelation and multi-collinearity tests and standardization were also conducted before modeling VOR. The results showed that human factors affected more the health of the Shazand Watershed rather climatic and hydrologic factors. The VORs of 0.33, 0.32, 0.34, and 0.37 for 1986, 1998, 2008, and 2014, respectively, indicated moderate health for all study years. In addition, sub-watersheds has shown important spatial variability in the health state. The results of the improvised method provided a reliable basis to designate reasonable strategies for sustainable land management and development leading to integrated management of the watersheds. |
