Densimetric Monitoring of Suspended-sediment Concentrations, Northeastern Georgia

Differential pressure transducers can be used to monitor the suspended-sediment concentration in a water column. Suspended sediments with densities greater than water increase the fluid density, which is determined by measuring the fluid pressure change between two depths. Lewis and Rasmussen (1999) used a densimetric technique under controlled conditions to determine suspended-sediment concentrations and particle-size distributions. Results from a study that used similar laboratory techniques and newly developed in situ methods are summarized herein and condensed from Calhoun (2000). Applications on two tributaries to the South Fork of the Broad River in northeastern Georgia demonstrate that stormflow suspended-sediment concentrations induce large temporal changes in fluid density. The influence of bedload sediment transport also is demonstrated by placing the deeper port in a position that tracks fluid density changes in the mobile bed zone.