Il rilevamento di DTM per analisi morfodinamiche

The present work arises from the need to monitor an area of sufficiently limited extension through ground survey by means of traditional or GPS techniques, aimed at achieving a prescribed accuracy and, most of all, describing the ground in relation to the requested applications. A typical application is the morphodynamic analysis of a braided river, namely a river consisting of more than one channel contributing to flow and sediment transport. Such channels are very unstable, so braided rivers pose difficult problems of river management. Fluvial engineers often need frequent and detailed surveys in order to monitor the motions of channels. Such need leads to onerous field measurements. In the present work we investigate how to optimise the topographic survey of braided rivers, in the sense of reducing the number of topographic points that we have to survey, selecting their distribution such to reproduce at best the complex bed surface. Starting from synthetic DTMs, different survey points and different interpolation methods are tested in a didactic approach through GIS open source GRASS. Hence, we have derived useful indications on how to reproduce digital terrain models that describe satisfactorily the morphology of a braided river with the lowest effort. The above approach has been applied to a field survey of a braided reach of Borbera River (AL) .