The 2009 Digital Surface Model (DSM) dataset consists of single band rasters at 1-meter pixel resolution that were generated to orthorectify a four band ortho imagery acquisition, and to support development of additional GIS products. Each pixel represents the elevation of the surface at that point expressed as NAD83 ellipsoid height. The DSM is a reflective surface DSM which provides elevation data on open ground (e.g. bare soil, rocks, and water), as well as aboveground terrain features including buildings, trees, and vegetation that cover otherwise open ground. The Digital Surface Model (DSM) was generated by automatic correlation of stereoscopic imagery collected from approximately 5,950 ft to 9,000 ft above mean sea level at 20-cm resolution with a Leica ADS40 SH52 digital multi-spectral sensor May 25, 2009 – June 1, 2009. Data were collected during a period of low steady river flow of approximately 8,000 cubic feet per second released from Glen Canyon Dam, however, tributary flows primarily from the Little Colorado River raised the approximate discharge to 9,000 cubic feet per second during the data collection from River Mile 61 (referenced by distance downstream from the confluence of the Paria River) down to River Mile 224 (Diamond Creek confluence) and possibly further downstream. The data are for the segment of the Colorado River corridor from Glen Canyon Dam downstream to Pearce Ferry, AZ.