HomeMy WebLinkAboutPVH HEALTH SYSTEMS, HARMONY CAMPUS, 3RD FILING, PRIMARY CARE PLAZA - FDP - 32-98H - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTVICINITY MAP
SCALE:1" = 1500'
1
13.1 cfs flow will combine with the 2.8 cfs from basins F and G, and continue east towards the
permanent Swale, located along the east boundary of the PVH Site.
The private roads north and south of the parking lot (basins A, B, F, & G) will convey their flows
east in the curb and gutter. Upon termination of the roadways, the flows will spill east over riprap
and into the temporary swales. The temporary swales will convey the flows east and into the
permanent Swale, located along the east boundary of the PVH Site. It is important to note that the
temporary and permanent swales will be grass -lined to provide a mechanism for pollutants to
settle out, before entering the downstream conveyance. The permanent Swale will convey the
storm flow south and into the detention pond in the southeast comer of the site. The detention
pond will be grass lined and an extended detention outlet structure will be provided, as noted in
the PVHS Harmony Campus Infrastructure Drainage Report, dated May 12, 2004.
The remaining eastern portion of the Primary Care Plaza, including the roof of the building, will
flow east overland and into the permanent Swale located along the east side of the PVH Site. This
flow will combine with that from the parking lot, and collectively, the flow will be conveyed
south as mentioned above.
DETENTION AND WATER QUALITY
The detention pond will be partially constructed at this time. The outlet structure will be
constructed in its final form with the orifice size being constructed for entire the site. The
detention pond will be constructed to approximately one-half of its ultimate size.
Riprap placement was utilized at all concentrated storm release locations, with the shape and
dimensions of the Rprap installation determined by the geometrics of the swales, rather than a
calculated area and volume through the UDFCD spreadsheet. Riprap calculations can be
provided if needed.
EROSION CONTROL
Erosion Control BMP's for the Primary Care Plaza site will include gravel filters for the 5' Type
R and CDOT Type D area inlets, erosion control fence along the south and east sides of the site,
grass -lined swales and detention pond, and an extended detention outlet structure.
Thank you for your time and consideration. If you have any questions, please let me know.
Yours Sincerely,
:3L a
John Gooch, EIT
Project Engineer
Jim Allen -Morley, P.E.
Senior Project Manager
Stantec Consulting Inc
209 South Meldrum Street
Fort Collins CO 80521.2603
Tel: (970) 482.5922 Fax: (970) 482.6368
stantec.com
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Tuesday, May 22, 2004
Basil Harridan
City of Fort Collins
Storm Water Utilities
700 Wood Street
Fort Collins, CO 80521
RE: PVHS Harmony Campus Primary Care Plaza
Dear Basil:
The Primary Care Plaza is a project that consists of an office building and parking (approximately
2.6 ac) that is located at the southeast corner of Snow Mesa Drive and the north access road. The
purpose of this addendum is to show compliance with the PVHS Harmony Campus Master
Drainage Plan.
SITE DESCRIPTION
The site is now a fallow field that drains to the south and southeast. In the proposed condition,
the site will be located in drainage basin 107 (total 3.8 acres), as shown in the PVHS Harmony
Campus Infrastructure Drainage Report, dated May 12, 2004. An 11 x 17 exhibit has been
provided for basin 107.
MASTER PLAN COMPLIANCE
The current site fits within the 80 percent impervious area assumption that has been made in the
Master Drainage Plan. Basin 107 releases at a I0-year flow rate of 11.68 cfs and a 100-year flow
rate of 33.63 cfs. The site will drain via curb and gutter, cross -pans, area inlets, storm drain, and
temporary swales to the east and into a permanent swale, located along the east PVH property
line. The permanent swale will transport the runoff south, under the fire lane, and into the
partially constructed detention pond. It is anticipated that there will be some form of a permanent
swale along the eastern property line of PVHS Harmony Site. The location of the swale may be
relocated in the future depending on how development occurs.
SITE DRAINAGE
Drainage from the western and central portion of the site will be conveyed to the center of the
parking lot, where two, CDOT Type D Inlets (in sump) will capture the 6.2 cfs and 4.9 cfs flows
(see provided calculations for basins C & D). The combined 11.1 cfs storm flow will then be
directed south and east in 19" x 30" elliptical RCP. Meanwhile, the 2.0 cfs flow from basin E
(southeast portion of the parking lot), will be conveyed southeast and into the proposed 5' Type R
Inlet (in sump). Here, the flow will be conveyed northeast in 15" RCP and will combine with the
11.1 cfs flow from basins C•and D. The combined flow from basins C, D, and E (13.1 cfs), will
be conveyed southeast via 19" x 30" elliptical RCP, and into the proposed temporary swale. The
L� Final
Drainage and Erosion
Control Report
Stantec
Poudre Valley Health Systems
Harmony. Campus
Primary Care Plaza,
Fort Collins, Colorado
June 22, 2004