HomeMy WebLinkAboutCHOICE CENTER MIXED-USE REDEVELOPMENT - FDP - FDP110002 - CORRESPONDENCE - DRAINAGE REPORT (6)Page 2 of 2
The project design engineer has been evaluating lining or replacing the CMP which may be acceptable
depending on the method proposed. The CMP section probably should be replaced. There have been
discussions with your design team about repairing the joints on the RCP which may be acceptable once
we hear what is being proposed. One other option being considered is using an alternative route for a
new storm sewer.
Another issue is that there are no easements for the pipes which cross private property. The CMP is
primarily on the Maytag Appliance/Al's Granite site and the RCP crosses the Dairy Queen site. An
easement is needed from the private property owners prior to approval of the final PDP.
A couple of other comments on the proposed drainage system are: one that the new 12 inch pipe shown
to carry Spring Creek flows needs be increased to 30 inches to match the pipe size through the railroad
embankment: and another is that we prefer to have it connect into the existing 48 inch pipe instead of
connecting it into the existing headwall of the College Ave. bridge. That would avoid getting into
Spring Creek and avoid the need for a floodplain use permit.
This outfall system is the primary issue remaining for the Stormwater approval of the final PDP. It is
urgent to get a resolution.
6/9/2011
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Ted Shepard
From: Glen Schlueter
Sent: Friday, April 22, 2011 10:43 AM
To: 'Herman Feissner'; Jason Claeys Qclaeys&vajva.com); 'jimsell@jimsell.com'
Cc: Ted Shepard; Marc Virata; Walker May; Wes Lamarque
Subject: Choice Center drainage outfall system
The purpose of this memo is to discuss the existing and proposed drainage outfall system on the Choice
Center site.
The existing system was built when the property was a mobile home park and was still in the County. It
has been reported that the mobile home park owner used whatever materials were available and installed
the system on his own, probably in phases. This has always been and is still today, a private storm water
conveyance system. The City has no ownership or maintenance responsibilities for this section of pipe.
At that time, Spring Creek was conveyed under the railroad embankment through a large box culvert.
The owner installed a pipe to carry the low flows of Spring Creek from the box culvert, at the Railroad
embankment, through his site to just upstream of the College Ave. bridge. There were no County
approvals or inspections, and no easements were dedicated. The box culvert was later plugged in 1988
when the Stormwater utility bored three pipes through the railroad embankment to the south and created
Creekside Park by buying out an adjacent mobile home park and several buildings. However, to
preserve the historic flow path, the low flow pipe remained in place and a 30 inch pipe was extended
through the old box culvert.
In September of 2008, during the preliminary project development plan (PDP) review, one of the
Stormwater comments was that verification of the existing pipe materials and conditions was needed for
the final PDP in order to evaluate the adequacy of the system. When the first final PDP was submitted,
this information was not included. Due to the importance of obtaining this information, Stormwater
maintenance crews were directed to assist even though this would normally be the responsibility of the
developer. Stormwater crews were used to flush and televise as much of the system as was possible.
That work was just finished recently.
There is a small drainage system behind the existing commercial buildings that could not be flushed or
televised because it has sharp bends and is too small for City equipment to get into. This system is not
part of the new development, and it will not be required to be upgraded at this time.
There are two major sections of the existing outfall that are proposed to be reused. One consists of a 48
inch corrugated metal pipe (CMP), and the other section is a 48 inch reinforced concrete pipe (RCP).
The televising showed the pipe material changes at the retaining wall at the north edge of the Dairy
Queen site. The CMP is in really poor condition. One section is partially collapsed, and tree roots have
grown into the pipe restricting the capacity. In addition, CMP is not a pipe material accepted in the City
of Fort Collins. The RCP was not installed correctly and curves both horizontally and vertically with
large gaps at one side of most of the joints. There is also a partial blockage at the junction of the CMP
and RCP that City crews were unable to remove. These two sections of pipe previously carried the low
flow of Spring Creek, but are now shown to be the primary outfall for the project and would not carry
Spring Creek flows. The City of Fort Collins will not even consider acceptance of these pipes without
substantial rehabilitation improvements or replacement.
6/9/2011