I-10 Twin Peaks Traffic Interchange, Environmental Assessment

Affected Environment and Environmental Impacts October 2005
between the westbound lanes and the westbound frontage road. There are
numerous private wells in the area as well. According to the Arizona Department
of Water Resources, at least 21 registered wells are located near the study area.
There may also be other, unrecorded wells within the area.
Impacts
No Build Alternative
The no build alternative would not affect the existing utilities within the project
area.
Preferred Alternative
The utilities of greatest concern within the project area are the 138 kv TEP
transmission lines, the UPRR, and the Kinder Morgan high-pressure petroleum
lines. As discussed in Chapter 3, Alternatives, the preferred alternative was
designed to avoid relocation of the 138 kv TEP transmission lines. Subsequent to
the selection of the preferred alignment, design changes were required. The UPRR
proposed to add a second track on the east side of the existing track and to increase
the elevation of the added track above that of the existing track. In addition, revised
traffic projections indicated that additional traffic lanes on the bridge over the UPRR
may be needed. As a result, the height of the bridge over the UPRR was adjusted
and the bridge width was increased to accommodate more traffic lanes at a later
time. These design changes would require that one or more of the transmission line
towers be relocated or raised.
While setting the proposed bridge deck over the UPRR, temporary impacts to train
traffic may occur; however, the UPRR has been involved in the planning of the
project and would issue right-of-way grants or agreements for the bridge over their
facilities. To issue these grants or agreements, UPRR would review the plans for
the preferred alternative to ensure that the project met current UPRR standards for
bridge design. UPRR would be involved also in the sequencing of construction
plans to ensure that temporary disruptions to train traffic would be minimized.
UPRR has been involved in the project since the beginning and has been a
participating member of the Technical Advisory Team (TAC) for the project.
Several meetings with the UPRR have been held in addition to the TAC meetings.
The UPRR would continue to be involved throughout the project.
According to plans provided by Kinder Morgan, the proposed improvements
would avoid the high pressure petroleum lines. This would be verified during final
design, by potholing utilities to verify their locations. Other utilities within the
project area may require slight adjustments. The preferred alternative would pipe
and bury portions of the CMID irrigation canal that is located along the east side of
I-10. Utility coordination was initiated as part of the planning process and would
continue throughout the course of the project. Schedules for any utility
adjustments would be closely coordinated to minimize interruptions and
inconvenience to customers.
Interstate 10 Traffic Interchange at
Twin Peaks/Linda Vista
4-98
Project No.: NH-010-D (AIW)
TRACS No.: 10 PM 236 H5838 01D