I-10 Twin Peaks Traffic Interchange, Environmental Assessment

Affected Environment and Environmental Impacts October 2005
agreement, as revised to address research design for treatment of archaeological
resources, has been followed for this proposed project and would continue to be
followed throughout the remainder of the project.
In addition, ADOT interim procedures for treating the historic state highway
system were developed in 2002. These procedures require the collection and
documentation of information from the historic highway before construction that
would impact these facilities.
SHPO Concurrence
SHPO has reviewed the cultural resources report prepared for this project and has
concurred with all of the eligibility findings except that of the Tucson-Casa
Grande Highway. SHPO stated that the segment of roadway within the project area
contributed to its eligibility to the NRHP and that a project specific treatment plan
would be needed (see letter in Appendix D).
Conclusion
The cultural resources report prepared for this proposed project recommended a
determination of adverse effect because of proposed project impacts on two
National Register-eligible properties: the Tucson-Casa Grande Highway (SR 84)
and the Stewart Brickyard archaeological site. A strategy for mitigating adverse
effects on these facilities was developed. Potential impacts on four other nearby
National Register-eligible properties were evaluated and the project was
determined to have no adverse effect on the historic qualities that make those
resources eligible. Three other resources within the area of potential effect were
recommended as ineligible for the National Register, and two other previously
recorded properties had been destroyed.
Socioeconomics
Demographics
According to the U.S. Census Bureau, the study area consisted of five census tracts
within Pima County and the Town of Marana (Census Tracts 44.16, 44.20, 46.29,
46.30, and 46.39), which represented a total 2000 population of 21,480. These
census tracts are presented in Figure 4-5. Selected 2000 U.S. Census Bureau data
from the five census tracts were compared to the same data for the Town of
Marana, Pima County, and the State of Arizona in Table 4-10. Census data for
these tracts is summarized in the following paragraphs.
Census Tract 46.16 was the largest of the tracts, with a population of 8,841
persons. Housing in this tract tended to be newer (94% constructed 1990 or after)
and more frequently occupied by the owner (90.7%) when compared to the other
tracts, the Town of Marana, Pima County, and Arizona. This tract also had a
higher median family income ($60,172) when compared to the other tracts, the
Town of Marana, Pima County, and Arizona. This census tract could be
Interstate 10 Traffic Interchange at
Twin Peaks/Linda Vista
4-77
Project No.: NH-010-D (AIW)
TRACS No.: 10 PM 236 H5838 01D