HomeMy WebLinkAboutOLD TOWN NORTH SUNTERRACE TOWNHOMES - FDP - 16-09/A - CORRESPONDENCE - (3)Page 2 of 2
worked out to reduce overall review time if sub drains are required.
Please respond to this email to confirm that the subsurface water investigation report is required. It is my
understanding that the 3' below sub grade waiver will not be allowed due to the sanitary infiltration issue. As
an alternative, would a more water -tight sewer pipe be an acceptable solution?
Sincerely,
Cody Geisendorfer, PE
Shear Engineering Corporation
Civil and Structural Engineering
4836 S. College Ave. Suite 12
Ft. Collins, CO 80525
P 970.226.5334
F 970.282.0311
www.shearengineering.com
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Ted Shepard - Re: Old Town North Second Filing - Sunterrace Townhomes - Subsurface
Water Investigation Report
From: Sheri Langenberger
To: cgeisendorfer@shearengineering.com
Date: 10/27/2009 1:03:42 PM
Subject: Re: Old Town North Second Filing - Sunterrace Townhomes - Subsurface Water Investigation Report
CC: 'Brian Shear; 'David Kasprzak'; Erika Keeton; Helen Migchelbrink; 'LLC'Triune Holdings'; Roger
Buffington; Steve Dush; Susan Joy; Ted Shepard; WKnutson@CTLThompson.com
Cody,
Engineering has discussed this issue and the City Engineer is willing to grant a waiver to the Subsurface Water
Investigation report requirement if a signed and stamped letter (by a Colorado Licenced Engineer) is provided
that certifies that the street subgrade elevations will be a minimum of 3 feet above the "maximum" predicted
(seasonal highest) water table, that the roads will be designed to handle the worst possible high ground water
scenario, including subdrains, and that a note is placed on the plat that identifies that basements shall not be
allowed.
Otherwise a Subsurface Water Investigation report for this project will be required due to the high water table
information. The recommendations of this report will need to be implemented on the project.
Please let us know if you have any questions.
Sheri
Sheri Langenberger, P.E.
Engineering Development Review Manager
City of Fort Collins, Engineering Dept
970-221-6605
>>> "Cody Geisendorfer' <cgeisendorfer@shearengineering.com> 10/26/2009 10:54 AM >>>
Project No: 1646-01-98; Old Town North Second Filing_fting a replat of Blocks 6 and 9, Old
Town North and a portion of Tract "E" Replat of Evergreen Park); Ft. Collins
Client: Client: Sunterrace Townhomes, LLC
Sheri,
I talked to Wyatt Knutson @ CTL Thompson last week and he confirmed that they had observed groundwater
levels in open trenches for a 12 month period in 2007-2008. Unfortunately they did not take piezometric
readings. Wyatt did say that the groundwater was highly dependent on the Lake Canal ditch levels. He said
that within a few days of the ditch levels going down, the groundwater levels would go down as well. He also
said that the groundwater peaked at the interface between the lean clay with sand and the silty sand with
gravel (see attached bore log for reference). He said that the silty sand/gravel layer was very clean indicating
that water flows pretty well through that layer and then must go to the Dry Creek because it doesn't go above
that layer. This confirms the 2000 report data and puts the Sunterrace project and streets at a worst case of
about 3.5 feet plus or minus below proposed street sub grade (about 4.5 feet below proposed grade).
With this information and based on our conversations, the City will require a subsurface water investigation
report to determine if sub drains need to be installed under the sanitary sewer due to possible groundwater
infiltration into the City's sanitary sewer system. To our knowledge, the rest of the existing Old Town North
development does not have sub drains. Susan also recommended waiting on resubmitting until this item is
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