Figure S3: A cartoon illustrating the estimation of channel deposit volumes from the mapped cross sections. A) the cross sections are drawn. B) the along channel distance between the cross section is calculated and a triangular cross section is assumed. Multiplying the distance by the area provides an estimate for the volume contained in the tributary channel deposits. C) The cross sections are remapped and the widths have increased. To determine the volume of sediment deposited the triangular cross section and volume is recalculated with the new width and the previous volume is removed. D) if the width has stabilised, we assume no deposition has occurred. Therefore, we map the width of the actively incising channel and estimate the volume of sediment removed by the channel by again assuming a triangular cross section.