e Google Earth recent aerial photographs depicting existing conditions at the site and
surrounds;
e Surficial Geology of the Nashua South Quadrangle, New Hampshire;
e USGS 7.5 Minute Series Nashua South Quadrangle, New Hampshire; and
e Geologic Map of the Nashua South Quadrangle, Hillsborough County, New Hampshire
and Middlesex County, Massachusetts.
Existing Conditions
The area of investigation (the site) is located on the USGS 7.5-Minute Series Nashua South
Quadrangle. The Surficial Geology of the Nashua South Quadrangle identified surficial deposits
as sand and gravel or till on shallow bedrock. The ground surface is relatively level and flat as a
result of past roadway embankment construction.
The Bedrock Geologic Map of New Hampshire identifies rocks of the Berwick Formation
(Silurian) underlying the area of investigation. The Berwick Formation consists of “Biotite-
plagioclase-quartz granofels with minor schist and calc-silicate rocks — purplish gray, grayish-
green, and light gray to dark gray, locally sulfidic and rusty-weathering”.
The USGS topographic map indicates that the area of investigation is moderately sloped to the
east, toward the Merrimack River.
Project Description
MET has reviewed a plan titled “Daniel Webster Highway @ Graham Drive” Traffic
Improvements Nashua, New Hampshire” prepared by Greenman-Pedersen, Inc. Based upon our
review of this plan, one (1) mast arm is proposed as follows:
Northeast Corner of the DW Highway and Graham Drive Intersection:
The mast arm is 45-feet in length, and supports four (4) traffic signals and a luminaire. One
additional signal is mounted on the pole. The base plate reactions were not available at the time
of preparing this report.
SUBSURFACE EXPLORATION PROGRAM
Subsurface conditions at the site were characterized by advancing one test boring (B-1) at the
proposed traffic signal mast arm location. A probe (P-1) was also advanced approximately 6 feet
north of the test boring location to determine the consistency in the depth of auger refusal. A
Subsurface Exploration Location Plan is provided as Figure 1.
The purpose of the subsurface exploration program was to:
1. Characterize the nature and consistency of the soil units at the site and provide samples
for visual classification:
