If one species had to be chosen to preserve and restore, perhaps it should be cottonwood. Cottonwood-willow forests, where they exist and are healthy, indicated the presence of a viable riparian area, which is in turn the key to conserving great proportions of our native species. A reflection of the dire status of our riparian systems is that the Sonoran cottonwood-willow and Sonoran mesquite-cottonwood forests.

This Technical Data notebook has been prepared for a Letter of Map Revision application for a portion of the Via Entrada Wash located in Pima County, Arizona. The objective of the TDN and LOMR submission is provide regulatory discharge rates and floodplain limits along the Via Entrada Wash using better topographic, hydrologic, and hydraulic data.