Estimating total sediment transport in a small, mountainous Mediterranean river: The case of Vouraikos River, NW Peloponnese, Greece

This paper presents the results of a five-year measurements program aimed at quantifying both suspended sediment and bedload transport in Vouraikos River, located in northwestern Peloponnese, Greece. Two sites along the main channel of the river were selected as measurement cross sections, while stage hydrographs for two distinct hydrological decades (1980-1990 and 2004-2014) were provided by a gauging station, operated by the Public Power Corporation S.A., situated at the midpoint between the two measurement sites. Rating curves were developed and riverbed samples were collected by bulk sampling and pebble counts. Laboratory measurements of transported suspended sediment concentrations were conducted to samples taken with a DH48 sampler. In the quest for cheap alternatives in river quality assessment programs, a 60 cm transparency tube was also tested. Regarding bedload transport sampling, a 152 mm opening Helley-Smith sampler was mostly used. For the estimation of bedload transport, a locally calibrated equation was developed applying methods proposed by various approaches that gave results very close to our bedload measurements. For the estimation of suspended sediment transport, a rating curve relating concentration C (mg/l) with discharge was developed. The transparency tube, calibrated locally, was found to accurately capture the dynamics of suspended sediment transport and is therefore suggested as a cheap and reliable alternative for river quality monitoring. Uncertainty of the results, estimated with Monte Carlo simulations, showed a larger spread in bedload calculations.