A Theoretical Approach to Improve the Applicability of the Catchment Connectivity Index

Several frameworks to evaluate the sediment connectivity—the physical linkage of sediment through the channel system—in a catchment have been proposed and verified in several environmental contexts. A simple but effective index (“catchment connectivity index”, CCI), considering the geomorphological characteristics of the channels and the connectivity between hillslopes and channels was proposed for estimating the sediment connectivity in Spanish rivers. The procedure to calculate the CCI is improved in this study, which suggest a modified index (“mCCI”) to make simpler and more realistic the hydrological and geomorphological description of the landscape elements influencing the sediment connectivity. The new procedure to calculate the mCCI reduces the need of many field surveys (whose output is often affected by errors when carried out by low-experience operators) and makes quicker the CCI application on a catchment scale (thanks to the large use of GIS).