Stream restoration design using the Stable channel Analytical Model (SAM)

The Stable channel Analytical Model (SAM) developed by the U.S. Army Corps of Engineers was used to estimate existing sediment transport capacity and develop channel design parameters for an urban stream restoration project. For the present application, the model was used to analyze a moderately incised reach on Millers Creek in Ann Arbor, Michigan. The SAM modeling evaluation is part of a larger effort to develop a comprehensive, 10-year sustainable restoration plan for the creek. Data gathered for the model included surveyed cross-sections and streambed profile and water surface elevations at 60 - 150 m intervals between sections, nine months of continuous pressure transducer data and staff gage readings; dry weather (two events) and wet weather (three events) grab samples of water column total suspended solids (TSS), and bed sediment particle size based on volumetric grab sampling. The SAM model has six different routines to calculate normal depth and 21 different routines to calculate sediment transport. Selection of the normal depth and sediment transport routines were aided by comparison to data. A series of stable channel widths, depths and bed slopes were calculated for the 2-year recurrence interval event using the SAM stable channel design routine. Preliminary results suggest that the creek has readjusted to the urbanized watershed flow regime.