Fig. 3. Spatial variation in sediment deposition and primary production variables (algal and riparian vegetation type biomasses) are represented at the scale of depth/stage “slices” (contours) within each relatively homogeneous river reach. Model users can define alternative reach structures (coarse vs. fine); the model default is 14 reaches averaging about 15 miles (24 km) in length. The default slice thickness (depth) is 2 feet (0.6 m).