Erosion Prediction in Ungauged Basins: Integrating Methods and Techniques (Proceedings of symposium HS01 held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 279, 2003, p. 241–248.

Abstract Morphometric attributes derived from digital terrain models are frequently substituted for hydrological parameters in ungauged basins. In many cases, however, the reliability of such derived data is severely hampered, both by errors inherent in the original data, due to map scale and map age, and by errors derived from interpolation and computation procedures. This is especially true in the case of alpine basins, where sedimentation and flooding typically occur in populated downstream regions on alluvial fans. Data obtained by interferometric SAR (InSAR) techniques can be successfully substituted for DTM-derived data, allowing the direct computation of fundamental, secondary DTM attributes such as slope and aspect. A set of ERS 1/2 SAR images of the Cellina alluvial fan in northeastern Italy has been acquired and interferometrically processed. Experimental results show that, compared to traditional DTM-based measures, SAR-based attributes appear to be more stable and should offer better characterization of the slope surfaces. Furthermore, the present availability of such images allows fast and inexpensive updating of local hydrological characteristics of an area after major flooding events.

Key words alluvial fans; Eastern Italian Alps; Italy; mountain streams; Northern Apennines; radar interferometry; sediment transfer