HomeMy WebLinkAbout1983 Oct 27 - Letter from Arch Assoc. to Richard O'Hearn, Engineer ...----
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I� SSOCIATES �
I CONSULTING HYDROGEOLOGISTS
1(1�}5 HALLET ST.,YARMOUTH PORT,MA55.02675
(617)362-9518
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October 27. 19$3
Mr, Richard J. 0'Hearn
R. J. 0'Hearn, Inc.
P. 0. Box 1263
East Dennis. Massachusetts 02641
Dear Mr, 0'Hearn:
I met with you and Mr. Robert David on Wednesday. October 26. 1983, at Mr.
David's property. Lot 13 on Merchant Avenue. in Yaxmouth. Alassachusetts. The
lot is located between Merchant Avenue and the west ahore of Folline Pond, We
examined three (3) test pita on a norttr south line along the west edge of the
lot adjacent to Merchant Ave. in order to define the earth materials p=e8ent.
T6e three pits produced similar results. That is. there were approximately 9
feet of primarily coarse to very coarse sand overlying a thin layer of pea[
over coarse gray sand. The upper 9 feet of sand was variable in details of
layering, iron-oxide content. and the grain-size distribution, The presence of
two small chunks of asphalt in the upper 5 feet of the northermost pit. the
structure of ihe materials. [heir position over very fresh peat, and the indi-
cation of marsh at this site on the 1961 Dennis topographic quadrangle lead me
to the conclusion that this lot consists primarily if not entiraj�� �F r=.� I
would guess that the fill was emplaced approximately fifteen years ago. Thia
estimate is based on geologic mapping of the Dennis quadrangle in 1966 by R. N,
Oldale of the U, S. Geological Survey. on the size of several recen[ly cut pine
tree stumps on the lot. and the presence of a 1-3 inch thick organic top eoil.
It is important to note that the fill is for the most part quite clean, poorly
graded. well drained sand. The sand is primarily (at least 80%) coarse to very
coarse eand with the remainder being very fine gravel (granules) and finer sand
sizea. Occaeional pocketa of fill contained traces of silt. and an occasipnal
bouder was found in the western side of the southern pit. This material is
typical of the naturally occurring soils in much of Yarmou[h and Cape Co¢� epd
undoubtedly was not brought from a very great distance.
One final observation is that the sand and peat layers below the fill are satu-
rated and the bottom several inches of fill are gray in color as they have been
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leached of iron. This indicates tha[ the water table is generally at or
slightly above the peat layer. or more than 8 feet deep. The water observed in
the second pit, vhich was the deepest. was brown in color indicating the pre-
sence of organic acids. The organic acids and apparent reducing conditione ip
the ground water are to be expected due to the decomposing vegetation of Lhe
old marsh deposits below the fill. The bearing of these observationa on the
suitability of the fill for on-lot sewage diaposal is that there would appear
to be sufficient depth of material above ground water that is not auitable fox
a potable supply.
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� In su�ary I find [ha[ Lot 13. Merchant Avenue. Yaxmouth. Massachuaetta, ovned
by Mr. Bobert David consiats of approximately 9 feet that is approxi.mately 15
I years old. The fill consists of generally clean. poorly graded. weli drained.
� coarse to very coarae sand. typical of much of the naturally occurring aoilc of
Yarmouth. The fill overlies sand and peat deposita of a recent merah vhich
� extends to the north of the lot. Ground water of poor quality occurs below the
ilot with the water table generally near the base of the fill.
� Very truly yours.
I Arch Associates
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(�t•,���.Kn-'
John A. Moser
Principal/Hydrogeologirt
JAM/ap
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