The Volume Ratio sediment routing method is a technique used in hydrology and hydraulic engineering to estimate the proportion of sediment transported from one location to another within a river or stream network. Specifically, it calculates the sediment volume ratio between two adjacent reaches or sub-reaches. The Volume Ratio Method directly pairs the sediment transport to the streamflow. For each time interval, sediment from the upstream elements is added to the sediment already in the reach. Deposition or erosion is calculated for each grain size to determine the available sediment for routing. The proportion of available sediment that leaves the reach in each time interval is assumed equal to the proportion of stream flow that leaves the reach during that same interval. This means that the all grain sizes are transported through the reach at the same rate, even though erosion and deposition are determined separately for each grain size.

\begin{aligned} & \text { Sed }_{\text {out }}=\frac{\text { Volume }_{\text {out }}}{\text { Volume }_{\text {channel }}} \text { Sed }_{\text {channel }} \\\\ & \text { Sed }_{\text{out}} = \text { Sediment Outflow }  \\ & \text { Volume }_{\text{out}} = \text { Water Volume Outflow }  \\ & \text { Volume }_{\text{channel}} = \text { Water Volume in Channel }  \\ & \text { Sed }_{\text{channel}} = \text { Sediment in Channel }  \\ \end{aligned}