HomeMy WebLinkAboutFile Documents.1112 Waters Ave.0089.2017 (37).ARBK CTL I THOMPSON
lN CO R. P D R A T Mb .'
April 10, 2017
1112 Waters Ave, LP
do Eastwood Development
0138 Prospector Road, Suite 4102
Aspen, CO 81611
Attention: Mr. Rob Cairncross
Subject: Infiltration Rate
1112 Waters Avenue
Aspen, Colorado
Project No. GS06119.000-120
CTL I Thompson, Inc. provided a geotechnical consultation for the resi-
dence planned at 1112 Waters Avenue (Project No. GS06119.000-120, report
dated March 29, 2017) to develop preliminary geotechnical engineering recom-
mendations for the project. This letter provides our opinions about infiltration rate
of the subsoils at the site and the use of drywells to dispose storm water.
Subsurface conditions encountered in our exploratory borings drilled for
our geotechnical investigations at nearby sites consisted of natural silty to clayey
gravel, sand, cobbles and boulders to the maximum drilled depth of 28 feet. We
have also had the opportunity to observe subsoils in foundation excavations for
projects near the subject property. Our experience in the area indicates the silty
to clayey gravel and sand is likely present for a significant depth below the pro-
posed drywell elevation. Laboratory test results on samples of the soils from this
part of Aspen typically indicate that the silty to clayey gravel and sand contains
less than 20 percent silt and clay size material.
Based on our field and laboratory data, and our experience with similar
projects in Aspen, we believe a drywell system can be successfully used at the
subject site to dispose of collected storm water. A hydraulic conductivity (k) of
0.034 to 0.0034 ft/sec for the silty gravel and sand soils is appropriate for design.
Pursuant to Page 8-117 of the City of Aspen Urban Runoff Management Plan
(URMP), we judge this hydraulic conductivity (k) correlates to a vertical percola-
tion rate faster than 3 inches per hour (i.e., 20 mins/inch).
234 Center Drive I Glenwood Springs, Colorado 81601
Telephone: 970-945-2809 Fax: 970-945-7411
Received
5/15/17
We appreciate the opportunity to work with you on this project. If you
have questions or we can be of further service, please call.
Very truly yours,
CTL I THOMPSON, INC.
±cio[201 -
J mes D. Kellogg, P.E.
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Division Manager ,4`37 }`•'
JDK:cd �..
cc: Via email to rob@sarick.com
1112 WATER AVE,LP 2
1112 WATERS AVENUE
PROJECT NO.GS0119.000-130
C:\Users\cdowning\Box\Projects\Glenwood Springs-Projects\GS06119.000\120\3.Letters\GS06119.000 120 L1.docx Received
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