HomeMy WebLinkAboutWATERGLEN PUD - FINAL - 71 93B - CORRESPONDENCE - CITY STAFF (13)- some of the swales are shown to be crossing the garden plots,
please correct this conflict.
Please show all cross -sections for the swales on the drainage
plan.
- Please use a larger scale for the next submittal, in order to
make the drainage plan more readable.
- Please provide all necessary drainage details.
Please document all off -site flows (Anheuser Busch) and include
them in the appendix.
At final the following requirements should be met:
- outlet controls for the detention ponds, as well as a grading
plan showing the required 1 foot freeboard should be provided.
- A SWMM analysis of the pond system should be prepared.
- A grading plan with building footprints and elevations, as well
as existing and proposed contours at two foot intervals is
required.
- A plat showing all necessary drainage easements is needed.
- Rip rap sizing calculations need to be provided where necessary.
- If you have any questions about this review, or what is required
for the final submittal, please do not hesitate to contact me at
the Stormwater Utility at (303) 221-6589
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This part of the review is concerned with the water quality issues
associated with the Cooper Slough.
The approximate wetland boundaries drawn on. the drainage plan show
some encroachment by development along the South end of proposed
Elgin Court on the outlined wetland area. The alignment of the
road will need to be adjusted to prevent that.
It is further suggested in order to enhance water quality in the
slough that the following alternatives be explored.
- The bottom of the detention ponds along the slough should be kept
close to. the groundwater level in order to create an additional
wetland buffer area in the slough (wet bottom pond). This will
create a wetland pond that would in turn enhance the habitat
quality in the corridor around the slough.
- The flow path in the detention ponds should be made as long as
possible in order to enhance water quality benefits to the slough
and minimize the amount and effect of pollutants associated with
urban runoff entering the stream ("first -flush" effects). Please
reference Urban Drainage and Flood Control manual Volume 3 for
design criteria for extended detention pond design criteria.
- Within the development area itself the system can be designed in
a manner as to minimize "Directly Connected Impervious Area"
(DCIA). This can be done through the use of grass lined swales,
irrigated grass buffer strips, berms, etc...
- The outlet structure from the detention area into the Slough
should be designed in a way to minimize sediment loading of the
stream.
The groundwater investigation provided seems to suggest that the
stream is fed by groundwater recharge from the irrigation return
flow drain tiles and from the canal. It is agreed that these
sources are probably the two main sources of water to the Slough,
however it is suggested that this analysis is preliminary and that
more longitudinal data (in time) should be collected to ascertain
this point.
This part of the review deals with the rest of the non -water
quality related comments:
- All grass swales with slopes less than 2% are required to have
concrete pans or underdrains. (A trickle channel may be needed for
larger swales. (Side slopes should be a maximum of 4:1 unless some
sort of stabilization is utilized.)
- Where is the 2.65 Ac. ft. of detention for Basin K being
provided? Please label correctly all detention ponds.
Utility Services
Storm:- -ter (
ICU i c6Gd�
From: Basil Hamdan, Stormwater Utility
To: Steve Olt, Planning and Environmental Services
Love and Associates.
Date: 4/20/9Z�
Subject: Waterglen, Preliminary submittal comments
It is .noted that this review was done using plans that were
submitted to the Stormwater Utility on April 4 th which are
different from more recent plans submitted to the Planning
Department.
The Boxelder overflow swale that conveys flows along I-25 is shownv
to be in the state Right Of Way. Formal approval from the Colorado`
Department of Transportation will be needed in that case before
this preliminary submittal is approved.
Cross -sections showing the swale, the berm, and the Interstate
highway are needed to verify how the flows are currently being
accommodated. Please show on these cross -sections the property
line and the Right of Way line. These cross -sections should be
done at least on three locations: one at the northernmost part of
the property where Q100 is around 250 cfs, in the middle section
and another one after the additional overflow from Boxelder Creek
(Q100= ,1450 cfs). Two cross -sections along East Vine Drive also
should be shown.
Two Existing buildings are.shown to be in the revised floodplain:
Since this reconfiguration of the floodplain will concentrate the
flows and thus cause higher velocities, these buildings will need
to be flood -proofed. Note again that the floodplain boundaries
shown on the Drainage plan submitted to the Stormwater Utility on
April 4 th is different from the one shown on the updated plan
submitted to the Planning and Zoning Board. Please clarify which
plan is the correct one.
?_ Matne:\- s • P.O. Boy 530 • Fort Collins. CO 30-522240530 • (303) 221-6539 • FAX (303) '_' 1-n_39
The City will be testing Vine Drive this spring. This testing will supply data (in June) to
determine the structural design of contemplated improvements to Vine Drive. As you
stated, because of the impact of construction vehicles, the Developer will require all
construction vehicles to use Mulberry and the I - 25 frontage road for deliveries.
On -Site Street Improvements
The on -site of Waterglen Drive and the applicable Vine Drive frontage do not meet the
Council approved criteria for street oversizing reimbursement. The City Code Section
24-121 (b) also states that :
" The City Council shall, by Resolution, adopt criteria to evaluate the community
benefit of streets in a development project to determine whether street oversizing
improvements are needed. If the City determines that the construction of
oversized street improvements do not convey a measurable community benefit
according to such criteria, then no monies expended by the developer for such street
oversizing expenditures shall be eligible for reimbursement by the City and the street
construction requirements for the development shall be limited to those
reasonably necessary to offset the traffic impacts of the development..."
Impact fees such as the Street Oversizing fee are used for public improvements on a
City wide basis and are not limited to the area of the property generating the fees.
I believe my decisions on these issues adequately represent the City's interests
regarding street infrastructure requirements for this development. If you are still
unsatisfied, you may appeal directly to the City Manager in accordance with Sec 24-120
(c) of the City Code.
Sincerely,
Gary Diede
Director of Engineering
cc: Steve Olt
Comm. ty Planning and Environments_ ,erviices
Engineering Department
May 2, 1994
Eldon Ward
Cityscape Urban Design, Inc.
3555 Stanford Road
Suite 105
Fort Collins, CO 80525
Re: Waterglen PUD
Dear Eldon,
I am responding to your letter dated April 20, 1994. The offsite street improvements to
Vine Drive that are required with the development of Waterglen PUD may be either of
the following two options:
1) The applicant may improve Vine Drive to 36 feet wide at full arterial
structure and design geometry between Waterglen and Lemay Avenue.
Upon completion and acceptance of these improvements by the city, the
applicant may enter into a repayment agreement with the City. Upon subsequent
development abutting Vine Drive, the City then would attempt to collect one - half
the cost of the improvements fronting the subsequent development and
forward these monies to the applicant. A repayment agreement is normally
10 years in duration, but may be extended. The offsite improvements to Vine
Drive will be needed by the development of the Waterglen Site. Vine Drive is
not now planned, nor contemplated to be included in the City's Capital
Improvements Program until at least 1997. Adding an additional fee to the
normal building permit impact fees is not an option for this development, if it is
intended that the City will be responsible for constructing the offsite
improvements.
2) The applicant may widen to 36' and overlay the existing surface of Vine Drive
between Waterglen and Lemay Avenue in order to extend the service life of
the pavement by 10 to 15 years. The City will determine the timing for such an
over lay to allow some development at the request of the Developer.
Under this option, none of the improvements to Vine Drive would be eligible for
a repayment agreement with subsequent development.
281 North College Avenue • P.O. Box 580 • Fort Collins, CO 80522-0580 • (303) 221-6605