I-10 Twin Peaks Traffic Interchange, Environmental Assessment

Affected Environment and Environmental Impacts October 2005
viewpoints and then given a Visual Impact Rating (VIR) of: low, moderate,
moderately high, or high.
No Build Alternative
The no build alternative would have no effect on visual resources within the
project area.
Preferred Alternative
There are general visual impacts that would affect the entire project area, not only
views from specific viewpoints. The visual short term impacts during construction
would affect most viewpoints. Grading would affect existing topography,
vegetation, and vistas and large construction vehicles would be visible from
adjacent land. Barren slopes and the project in various stages of development
would be visible intermittently throughout project construction.
Offsite structures visible from the proposed roadway that would impact visual
quality are the Arizona Portland Cement plant, commercial land uses along the
frontage roads, and the TEP transmission line. These visual elements, which would
be considered less desirable, would become more noticeable when viewed from
the proposed elevated roadway section; however, the proposed elevated roadways
would enhance the roadway users’ view of the Tucson, Santa Catalina, and
Tortolita Mountains, which would be desirable views.
View from Twin Peaks Road
The preferred alternative would affect the existing open space views to the east
from Continental Ranch. The proposed improvements would blend with existing
land uses and traffic near the interstate; however, the alternative would contrast
with the open space views and landscapes in the floodplain. In addition, residents
on the south side of Twin Peaks Road would have views blocked by a proposed
17-foot tall noise wall. Lighting at the signalized intersections and light and glare
from vehicle headlights would be visible also. In this area, there would be a
moderate adverse change to the existing visual resource and a moderate viewer
response; therefore, views from Twin Peaks Road would be moderately impacted.
View from the High Flow Channel of the Santa Cruz River
The preferred alternative would allow greater access to floodplain views.
Background views to the west (Tucson Mountains) would be enhanced, because of
the elevated roadway; however, views of the developed areas would be affected
negatively by the proposed 17-foot tall noise walls on the south side of Twin Peaks
Road. Depending on the vantage point, background views to the east may be
obstructed by the interchange/bridges or enhanced by the elevated roadway. In this
area, there would be a moderate adverse change to the existing visual resource and
a moderate viewer response; therefore, views from the high flow channel of the
Santa Cruz River would be moderately impacted.
Interstate 10 Traffic Interchange at
Twin Peaks/Linda Vista
4-43
Project No.: NH-010-D (AIW)
TRACS No.: 10 PM 236 H5838 01D