HomeMy WebLinkAboutSite Certifications - 07/22/2008Stantec Consulting Inc
209 South Meldrum Street
' Fort Collins CO 80521.2603
Tel: (970) 482-5922 Fax: (970) 482-6368
stantec.com
Stantec
July 16, 2008 6�
Mr. Jay Barber
Fort Collins Stormwater Utility
700 Wood Street
Fort Collins, Colorado 80522
Re: Overall Site Storm Drainage Certification for Front Range Village
Dear Mr. Barber:
The purpose of this report is to complete the Overall Site Storm Drainage Certification for the
Front Range Village site in Fort Collins, Colorado.
King Surveyors visited the site on several occasions between April 2, 2008 and July 11, 2008, to
measure invert and rim elevations of the storm sewer manholes and structures, slopes of the storm
pipes, and generate final pond contours.
Stantec Consulting Ltd. also visited the site on April 3, 2008, June 2, 2008, and July 15, 2008 to
confirm the installation of the storm pipe, structures, and erosion control measures, as seen in the
approved utility plans. Stantec also walked the site to confirm grades outside the buildings meet
the intent of the approved plans. Visual observations were made to confine positive conveyance
of stonewater away from the buildings.
The proposed detention ponds serving the Front Range Village site meet the intent of the
approved plans and provide water quality and detention for the site. As mentioned previously in
the Target and Lowes Drainage Certification dated June 3, 2008, Ponds A and D are short of the
required detention volumes by 0.28 ac-ft and 0.16 ac-ft respectively. These shortages appear
negligible. Ponds A and D would have to be raised approximately 0.18' and 0.05' respectively to
meet the required volumes. Because both ponds provide 1' of freeboard (above the provided 100-
year water surface elevations) and all ponds have been permanently seeded, Stantec does not feel
re -grading the ponds is necessary to gain the volume.
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Overall Site Storm Drainage
Certification for Front Range Village
Page 2 of 3
Ponds B, C, E, and F all meet the intent of the approved plans and exceed the required detention
volumes called for in the Final Drainage and Erosion Control Report for the Front Range Village
site (see attached Detention Pond Exhibit). It is important to note that Pond F was intended to be
a wet -pond with a static depth of approximately 3 ft. to 4 ft. However, based on the request of the
developer, Pond F will not serve as a wet pond and there is no intention to retain water in the
pond. Therefore, Pond F will have extra detention capacity, in relation to the approved hydraulic
modeling. Because the pond was planned to provide retention, the bottom of the pond is flat.
The developer has installed a sump pump in a stand pipe at the north end of the pond that will
allow for dewatering of standing water if necessary.
The storm drain systems, which convey runoff from the Front Range Village site to the respective
detention ponds, are installed and meet the intent of the approved plans. Proposed inlets, trickle
pans, curb cuts, curb chases, swales, and detention ponds are installed and meet the intent of the
approved plans and the Final Drainage and Erosion Control Report for the site. The proposed
storm drain pipe has been installed, and the record information provided for the storm drain
systems (see attached storm plan and profile sheets).
Seeding, landscaping, and hardscaping have been completed around and adjacent. to the
constructed buildings. Positive drainage away from the buildings to the proposed storm drainage
structures has been provided. Yard drains have been installed throughout the site to provide
positive conveyance of stormwater flows from landscaped and plaza areas into the proposed
detention facilities for the site. It is important to note that construction is still occurring in and
around Buildings 700 North and 700 South, and also between Buildings 300 and 400.
Landscaping and hardscaping will be completed in these areas once construction of the buildings
and associated parking lot improvements are complete
It is important to note that Lot 8 and Lot 9 are currently occupied by the construction trailers.
Drainage and grading improvements as well as permanent seeding for Lot 8 and Lot 9 will be
completed once the trailers are removed from the site. Furthemore, Pond F will also be
permanently vegetated and debris removed once the trailers are removed. Currently, temporary
diversions have been provided to allow stormwater from the Harmony Corporate Center, Lot 8
and Lot 9 to flow into Pond F. These temporary diversions will be replaced with permanent
conveyance measures into Pond F, once the construction trailers are removed from Lot 8 and
Lot 9.
Overall, the constructed improvements for the Front Range Village site, including the detention
ponds, storm drainage systems, structures, and appurtenances, and also the grading of the site,
appears to be in substantial compliance with the approved utility plans for Front Range Village
and the Final Drainage and Erosion Control Report for the Front Range Village Site.
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Overall Site Storm Drainage
Certification for Front Range Village
Page 3 of 3
This certification is signed and stamped. By signing this letter, I attest that to the best of my
knowledge, the conditions of the site are as shown on the attached redlined photocopy. Failure to
properly disclose all known information could result in the rejection of this certification and
prevent the release of any storm water utility holds on the Building Permit .or Certificates of
Occupancy.
Thank you for your time and consideration of this submittal.
Sincerely Yours,
Stantec Consulting Ltd.
L eM4
ohn Gooch
Project Manager
cc: Joe Johnson, Hoar Construction
Dave Brown, Bayer Properties
Tommy Alfano, Bayer Properties
File
An
Project Manager
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