Letter Preliminary Report of Phase 2 Data Recovery at AZ U:15:1(REC) on SCIDD Property and Trenching for Additional Canal Exposures on Federal Land Near Ashurst-Hayden Diversion Dam, Pinal County, Arizona


As authorized under the Arizona Water Settlements Act of 2004, the San Carlos and Irrigation Drainage District (SCIDD) is undertaking a 10-year rehabilitation project of its irrigation system. SCIDD is the non-Indian irrigation component of the San Carlos Irrigation Project (SCIP), which provides irrigation water to the communities of Florence, Coolidge, and Casa Grande in Pinal County, Arizona. The initial focus of the SCIDD Rehabilitation Project is the rehabilitation of the Ashurst-Hayden Diversion Dam and its associated headworks, which diverts water from the Gila River for SCIP; the armoring of a segment of the south bank of the Gila River, and the construction of a sediment removal pond and storage area downstream of Ashurst-Hayden Diversion Dam. Following consultation with project stakeholders on the results of Phase 1 data testing at AZ U:15:1(REC) (later AZ U:15:676[ASM]), a prehistoric site, and additional recording of historic features at two other sites, AZ U:16:303(ASM), the Dam Tender’s Complex, and AZ AA:3:215(ASM), the Florence-Casa Grande Canal, Reclamation directed Archaeological Consulting Services, Ltd. (ACS) to conduct Phase 2 data recovery at AZ U:15:1(REC) to excavate the known features and expose the prehistoric canal.

ACS excavated 13 features and subfeatures at AZ U:15:1(REC) and two additional exposures of the canal were located northeast of AZ U:15:1(REC). The excavation and subsequent artifact analysis reveal that AZ U:15:1(REC) was a Late Sedentary (Sacaton phase) short-term, seasonal farmstead. The additional canal (AZ U:15:8[REC]) exposures to the northeast of AZ U:15:1(REC) reflect a depositional environment that suggests they were very near the canal’s intake point along the river. Samples processed from the canal produced a weak ostracode result, but succeeded in providing a good radiocarbon date of A.D. 990 to 1150, which overlaps with the dates from AZ U:15:1(REC). The size of the canal, and the lack of laterals or parallel canals, strongly suggests that this was the uppermost extent of the Grewe-Casa Grande Canal system.

The project provides important new data for understanding Hohokam movement into the upper portion of the Middle Gila River Valley, its timing, and the resources that they focused on, wild and domesticated. Based on the results of the Phase 2 data recovery, Reclamation determined that these efforts had mitigated the adverse effects to both AZ U:15:1(REC) and AZ U:15:8(REC) that would result from the proposed project.

This is the preliminary end of field work report.

The final report can be found at tDAR ID: 377904.

Cite this Record

Letter Preliminary Report of Phase 2 Data Recovery at AZ U:15:1(REC) on SCIDD Property and Trenching for Additional Canal Exposures on Federal Land Near Ashurst-Hayden Diversion Dam, Pinal County, Arizona. E. Melanie Ryan. Tempe, Arizona: Archaelological Consulting Services, Ltd. 2012 ( tDAR id: 377893) ; doi:10.6067/XCV8XG9RZ1

Temporal Coverage

Calendar Date: 950 to 1150 (Site occupation date range)

Spatial Coverage

min long: -112.022; min lat: 32.686 ; max long: -110.731; max lat: 33.441 ;

Record Identifiers

BIA ARPA Permit No. (s): 2011/SCIP/ACS/WRO/001a

Pinal County Dust Permit No.(s): 10805

ASM Burial Agreement Case No.(s): 2010-038

Bureau of Reclamation Contract No.(s): R10PB32083

Arizona Blue Stake Case No.(s): 2012-011100817


General Note: AZ U:15:1(REC) (later AZ U:15:676[ASM]) is a late Sacaton phase Hohokam farmstead, and AZ U:15:8(REC) is a Hohokam canal that passes through the site. Both are the same age.

Redaction Note: Maps and other specific site locational information have been redacted from the publicly available documents. The redacted information is available as a restricted document; please contact the Bureau of Reclamation for permission to access it.

File Information

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