HomeMy WebLinkAboutCT 14-06; Afton Way; Addendum 2-Clarification of Geotechnical Recommendations Proposed Afton Way Residential Development; 2017-08-07•
Leighton and Associates, Inc.
A L EIGHTON GROUP COMPANY
Pebble Creek Companies.
301 W. 281h Street, Suite A
National City, CA. 91950
Attention: Mr. Gary Arnold
August 2, 2017
RECORD COPY
Initial
__ qj,,.,j,)
~
'------·-······ . -----·-·-------~
Project No. 11436.002
Subject: Addendum 2 -Clarification of Geotechnical Recommendations
Proposed Afton Way Residential Development
Carlsbad, California
References Leighton and Associates, Inc., 2014, Geotechnical Investigation, Proposed
Afton Way Residential Development, Carlsbad, California, Project Number
10690.002, dated September 29, 2014
BHA, Inc., 2017, Precise Grading Plans for Afton Way, Sheets 1 through 4
Drawing Number 495-98, received July 31 .
In accordance with your request and authorization, we have prepared this addendum letter
providing clarification of geotechnical recommendations for Section 6.7 Control of Ground
Water and Surface Waters provided in the above referenced report by Leighton and
Associates for the Afton Way Residential Development project located in Carlsbad ,
California. Specifically, this clarification addresses the Footing/Swale Detail on Sheet 2 of
the above referenced Precise Grading Plans (BHA, 2017). Based on our review of our
referenced report and precise grading plans, we provide the following:
As indicated in the above referenced report (Leighton, 2014), we recommend a minimum
slope and flow gradient of unpaved drainage swales within 5 feet of structures be at least
2 percent. Based on our review of the referenced grading plans by (BHA, 2017), the
RECEIVED
" u j
LAND Ot: \ ,_LOPMENT
ENGINE::ERING
3934 Murphy Canyon Road Suite B -205 • San Diego, CA 92123-4425
858 292.8030 • 858 292 0771 Fax
11436.002
center of the proposed unpaved drainage swales are proposed a minimum of 3 feet (i.e.
within 5 feet) from proposed structures and sloped at 2 percent minimum. Therefore, the
proposed unpaved drainage swales are in general conformance with our
recommendations.
The recommendations provided in this letter and our previous geotechnical reports are
based on preliminary design information and subsurface conditions disclosed by widely
spaced excavations. The interpolated subsurface conditions should be checked in the
field during grading and/or construction. Construction observation of all onsite
excavations and field density testing of all compacted fill should be performed by a
representative of this office.
If you have any questions regarding this letter, please contact this office. We appreciate this
opportunity to be of service.
Respectfully submitted,
LEIGHTON AND ASSOCIATES, INC.
William D. Olson, RCE 45283
Associate Engineer
Bryan E. Voss, PG 8709
Senior Project Geologist
Distribution: (1) Addressee, via email
(1) BHA, Inc., Attn: Mr. Bruce Rice, via email
-2-4
Leighton