# Investigation of a Gravel-Bed River's Pattern Changes: Insights from Satellite Images
## 5 Conclusions  
In the present work the stream pattern changes have been analyzed by identifying the evolution of morphological features formed at different time periods. The main results obtained in the present work can be summarized as follows:  
* different morphological features form between time periods characterized by frequent low-magnitude events with sporadic high peaks and time periods characterized by frequent high-magnitude events. * during the time period characterized by frequent low-magnitude events with sporadic high peaks, the active channels are mainly concentrated on one side (left part) of the study reach, where a series of downstream migrating bars form. During the time period characterized by frequent high-magnitude events, the channel tends to assume a single tread meandering pattern characterized by a prevailing lateral migration;
* the difference in the morphological features evolving between the two time periods could be related to the different vegetation distribution and sediment transport mechanisms induced by the floods. The vegetation cover, which always increases on the right part of the study reach, determines a sort of interface between the vegetated-dominated area, where the flow resistance is significant, and the flood-disturbance-dominated area, where the action by flow is significant. Especially during frequent low-magnitude events, interactions between coarse and fine fractions could determine that the coarse particles become more mobile affecting the bed-load transport and the associated migrating features; during the period with frequent high-magnitude events, the ratio of coarse to fine sediments is altered and the gravel material and woody debris are deposited. This furtherly facilitates the formation of vegetation islands in one side and the sediment deposition on the other one, forcing the channel to suppress the secondary channels and assuming a single tread pattern. In summary, the obtained results have shown that a combination of factors (such as the tolerances of vegetation species, the erosion and deposition of sediment, the transport of sediments and seeds) determine favorable conditions to channel pattern changes but, the frequency of occurrence of high-magnitude events should be especially considered in a fist-step analysis. This is because the frequency of occurrence of high-magnitude events influences, in turn, other important factors: on one hand it contributes to determine a variation of the typology of the vegetation characteristics; on the other hand, it affects the ratio of coarse to fine of sediments, the typology and dynamics of sediments and, consequently, the variation in sediment flux and the morphological features migration mechanisms. Although the data used are not comprehensive of other detailed local data, the present approach has allowed researchers to conduct a first-step analysis on dynamics of stream patterns changes, which could drive a successive, more accurate and specific field monitoring and measurements especially aimed to explain specific multiscale interaction processes among flow, bed and banks erosion and plan-form evolution. Furthermore, it should be noted that the approach presented is scalable and applicable by using other image sources. Future studies will be conducted to verify conditions for the changing configuration also at seasonal timescales. This paper represents some of the results of a research programme undertaken during author's research fellowship at Leibniz-Institut fur Gewasserokologie und Binnenfischerei im Forschungswerbund Berlin e.V.- IGB (Berlin), funded by Deutcher Akademischer Austausch Dienst-(DAAD).