Mapping of River Alluvium Along the Verde River and Major Tributaries, Central Arizona

In 2010, the Arizona Geological Survey (AZGS) released a series of 1:24,000-scale geologic strip maps showing the extent of Holocene channel and floodplain deposits along the Verde River and five large tributaries in central Arizona. The primary purpose of this mapping was to contribute to the legal differentiation of river subflow from groundwater in surrounding areas, as Arizona courts have established the lateral extent of Holocene river alluvium as a key component in delineating subflow zones. These maps also define the physical architecture and geomorphic framework of the river systems, depicting river and tributary deposits of Holocene to late Pliocene age, Pliocene and older basin filling deposits, and various bedrock units. We employed standard geomorphic and geologic criteria to differentiate and map river and tributary alluvial deposits of different ages. The degree of clast rounding, lithologic diversity, and landform/terrace slope were used to differentiate river from piedmont alluvium.Poster presented at 2011 Geological Society of America Annual Meeting in Minneapolis, Minnesota, 9-12 October.Documents in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact azgs-info@email.arizona.edu