The Linear Reservoir Sediment Routing Method employs a straightforward linear reservoir concept to guide the movement of sediment of various grain sizes within a given reach. During each time interval, the sediment load is determined based on the incoming sediment from upstream and local erosion or deposition processes. Importantly, sediment within each grain size category is individually routed through a linear reservoir, independently of the hydrological routing of water flow. This design allows sediment particles of different sizes to travel at distinct rates through the reach.

For precise parameter assignment, it is advisable to calibrate the model using observed data. This ensures that the parameter values accurately reflect the real-world conditions. The Component Editor, which is illustrated in the accompanying figure, provides a tool for making these adjustments.

The "Retention" parameter, analogous to the storage coefficient, plays a critical role in sediment routing within the reach. Sediment routing occurs separately for clay, silt, sand, and gravel. When employing the AGU 20 grain size classification, the same retention value is applied to all subclasses within each class. This retention value is essentially a representation of the median time it takes for sediment particles of a specific size class to traverse the reach. While this value can vary for each sediment size class, it often approximates the travel time for water within the reach.

Required Parameters

Parameters that are required to utilize this method within HEC-HMS include the retention parameters for each grain size.

A Note on Parameter Estimation

Estimating the retention parameters for each grain size typically involves a calibration process based on observed hydrological data.