Holocene mapping of the Verde River of Central Arizona
ARIZONA GEOLOGICAL SURVEY (AZGS)

In July 2010, the Arizona Geological Survey (AZGS) released five new geologic map sheets showing the extent and age relationships of Holocene channel and floodplain deposits along the Verde River.  A 51-page report accompanies the maps.

Snippet of Holocene Geologic Map

The perennial Verde River winds 178 miles through central Arizona, from its headwaters in the Chino Valley to its confluence with the Salt River, east of Phoenix.  The river watershed blankets 6,500 square miles and drains parts of Coconino, Gila, Maricopa and Yavapai Counties. In 1984, Congress selected 40 miles of the Verde River for the U.S. National Wild and Scenic Rivers program  (http://www.rivers.gov/wsr-verde.html). 

Arizona’s rivers are an integral part of the State’s water resources.  In an ongoing effort to understand Arizona’s waterways, the Arizona Department of Water Resources engaged AZGS to map Holocene-age deposits of the Verde River as part of the Gila River stream adjudication program.

AZGS’s mapping team constructed geologic strip maps of a two-mile wide swath centered on the river’s active channel and running the entire course of the river. Geologic mapping was overlain on USGS 7.5 minute, 1:24,000-scale topographic maps. The team used earlier mapping, aerial photography, and extensive field work – establishing GPS stations on approximately one-mile the length of the river – to map modern and recently active channel and floodplain deposits, river terraces and adjacent tributary deposits, eroded older basin deposits, and bedrock.

Location of Verde River in Central Arizona

The geologic maps provide foundational geologic data for deciphering the recent history of the Verde River system. Young Verde River sediments – those deposited over the past 10,000-years -- are subdivided by age and broadly grouped into two classes: channel deposits that comprise mostly sand and gravel; and, overbank floodplain and terrace deposits that consist of sand, silt, and clay with minor gravel.

Stakeholders – water managers, civil authorities, ranchers, wildlife biologists, archeologists, environmentalists, and the Arizona public – should find these maps indispensible for physical and biological studies of the Verde River riparian corridor.

Both the geologic maps and technical report are available free in PDF format at www.azgs.az.gov/publications_online.shtml .

Printed copies and the GIS data are available at the AZGS Map & Book Store at 416 W. Congress, Suite 100, Tucson, 85701. To order call 520-770-3500 or fax 520-770-3505.

Full Citation of Verde River Holocene Maps.

DM-RM-2: Mapping of Holocene River Alluvium along the Verde River, Central Arizona, J.P. Cook, P.A. Pearthree, J.A. Onken, A. Youberg, E.R. Bigio, 2010.

DM-RM-2 A-B: Mapping of Holocene River Alluvium along the Verde River, Central Arizona, J.P. Cook, E.R. Bigio, A. Youberg, P.A. Pearthree, P.K. House, 2009.

DM-RM-2 C-D: Mapping of Holocene River Alluvium along the Verde River, Central Arizona, J.P. Cook, E.R. Bigio, A. Youberg, P.A. Pearthree, P.K. House, 2009.

DM-RM-2 E-F: Mapping of Holocene River Alluvium along the Verde River, Central Arizona, J.P. Cook, E.R. Bigio, A. Youberg, P.A. Pearthree, P.K. House, 2009.

DM-RM-2 G-H: Mapping of Holocene River Alluvium along the Verde River, Central Arizona, J.P. Cook, E.R. Bigio, A. Youberg, P.A. Pearthree, P.K. House, 2009.

DM-RM-2 I-J: Mapping of Holocene River Alluvium along the Verde River, Central Arizona, J.P. Cook, E.R. Bigio, A. Youberg, P.A. Pearthree, P.K. House, 2009.

To download the above publications, go to AZGS Online Publications


ARTICLE AUTHOR:
AZGS Staff

Arizona Geological Survey
Tucson, AZ
michael.conway@azgs.az.gov


 

 

 

 

 












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