M-2018-09-17- Groundwater ElevationsPROJECT MEMORANDUM
181 BALLARDVALE STREET, SUITE 202, WILMINGTON, MA 01887 TELEPHONE: (978) 570-2999 FACSIMILE: (978) 658-3044
An Equal Opportunity Employer
REF: MAX-2013034.19
DATE: September 17, 2018
TO: Douglas McDonald, Stormwater Manager, Northampton Department of Public Works
FROM: Lindsey Barbee, P.E., Greenman-Pedersen, Inc. (GPI)
RE: Northampton – Reconstruction of Damon Road
Damon Road Infiltration Basin
Groundwater Elevations
On Tuesday, September 4, 2018, GPI recorded groundwater elevations in monitoring wells previously
installed at the location of the proposed infiltration basin for the subject project. This memo is being
provided to summarize the findings related to groundwater elevations.
The February 2018 groundwater level recordings performed by Briggs are as follows:
Exploration Ground Surface Elev. Approx. Water Elev.
B-1 128 ft. 117 ft.
B-2 127 ft. 116 ft.
B-3 125 ft. 116 ft.
The groundwater levels recorded on September 4, 2018 are as follows.
Exploration Ground Surface Elev. Approx. Water Elev.
B-1 128 ft. n/a (filled in)
B-2 127 ft. 117.5 ft.
B-3 125 ft. 118 ft.
The groundwater levels are consistent with the Test Borings report prepared by Briggs and dated
February 16, 2018. As stated in the report, no mottling or oxidation was noted in any of the borings
to suggest a historic high groundwater level higher than elevation 118 feet. As it relates to the
stormwater management design, the findings support the proposed infiltration basin design, for which
the bottom of basin elevation is proposed at elevation 120 feet. Two feet of separation from estimated
seasonal high groundwater will be maintained.
If you require additional information, please do not hesitate to contact me at 978-570-2997 or by email
at lbarbee@gpinet.com.