HomeMy WebLinkAboutReview of Rockfall Condition 01.25.2018H-PKUMAR
Geotechnical Engineering I Engineering Geology
Materials Testing 1 Environmental
5020 County Road 154
Glenwood Springs, CO 81601
Phone: (970) 945-7988
Fax: (970) 945-8454
Email: hpkglenwood@kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, Summit County, Colorado
January 25, 2018
Michael Scurlock
1566 Shepherd Lane
Glenwood Springs, Colorado 81601
mic h ae] . scu rl ock @ ri verrestorat ion .org
RECEIVED
JAN 2 6 2017
GARFIELD COUNTY
COMMUNITY DEVELOPMENT
Project No. 18-7-123
Subject: Review of Rockfall Condition, Lot 75, Spring Ridge Reserve PUD, Phase 4,
Garfield County, Colorado
Dear Michael:
As requested, the undersigned representative of H -P Kumar observed the hillside above the
proposed residence at the subject site on January 24, 2018, for potential rockfall impacts to the
proposed construction. HP Geotech (now H -P Kumar) previously conducted a subsoil study for
design of foundations at the site and presented the findings in a report dated April 29, 2016, Job
No. 116 082A.
Proposed Construction: We understand the proposed residence will be a one or two story,
wood -frame structure, with a walk -out basement level and attached garage on the lower -level.
The building will be centrally located in the building envelope, generally in the area of the
boring locations as shown on Figure 1 of the referenced subsoil study report. Foundation
excavations on the up-slope side of the lot could be up to about 8 to 12 feet to accommodate a
basement level.
Project Site: The subject lot is located on a small slope promontory generally with slopes up to
the north, northeast and northwest, at about 20 percent across the building pad portion of the lot.
The building pad area is bordered to the north by an abandoned, northeast to southwest trending
irrigation ditch and small berm bordering the ditch. Above the ditch, the terrain generally slopes
up at about 6 to 8 percent to the crest of the hill, about 250 feet above the ditch. Surficial soils
on the hillside above the proposed residence consist of relatively shallow colluvium, comprised
of silty, clayey sand with gravel, and small cobbles, overlying sandstone bedrock of the Maroon
Formation. Drainage on the slope above the proposed residence appears to be by sheet flow.
Michael Scurlock
January 25, 2018
Page 2
Conclusions and Recommendations: Based on our observations and professional experience,
we conclude that the slope above the proposed residence in its current configuration lacks
sufficient slope grade and potential rockfall objects to pose a hazard to the proposed residence,
and as such, rockfall mitigation measures are not warranted at the project site.
If alterations to the slope above the residence are planned in the future, we should be consulted to
review the planned alterations for potential rockfall and/or slope stability hazards.
If you have any questions or need further assistance, please call our office.
Sincerely,
H -P- KUMAR
James A. Parker, P.E., P.G.
Rev. by: SLP
JAP/ksw
cc: Garfield County Community Development — Dave Argo (dargo@garfield-caunty.com)
H-P%KUMAR
Project No. 18-7-123