HomeMy WebLinkAboutSUNSTONE VILLAGE PUD, 5TH FILING - FINAL - 42-89B - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTFort Collins • Colorado Springs
FINAL DRAINAGE REPORT
FOR
SUNSTONE VILLAGE 5TH SUBDIVISION P.U.D.
Project No. 248.8
November 1989
Prepared For:
The Group, Inc.
401 West Mulberry Street
Fort Collins, CO 80521
Prepared By:
Engineering Professionals, Inc..
2000 Vermont Drive
Fort Collins, CO 80525
TABLE OF CONTENTS
1.0 Location
2.0 Existing Conditions
3.0 Proposed Drainage
4.0 Conclusion
APPENDIX
Calculations
FINAL DRAINAGE REPORT
FOR
SUNSTONE VILLAGE 5TH SUBDIVISION P.U.D.
1.0 Location
Sunstone Village 5th Subdivision, previously known as Timberline Farm - Phase A, is
located within the northeast portion of the Timberline Farm Master Plan. The Master Plan area
consists of the west half of the southwest quarter of Section 32, T7N, R68W. The 5th
Subdivision consists of 20.2 acres bounded by undeveloped land on the west and south,
Caribou Road on the north and Harmony Village Mobile Home Court on the east. The property
is located within reach 2 of the Fox Meadows Drainage Basin.
2.0 Existing Conditions
The site has historically been used for agricultural purposes. Presently a portion of the
tract is being farmed with the remainder uncultivated. The property is a portion of a larger
basin which drains to the north. The site has slopes of 1 % to 3% with the north portion being
the steepest. Offsite drainage onto the site consists of sheet flow from the undeveloped area
to the west.
A swale has been constructed from the northeast corner of the site to the east along
the south side of Sunstone Village Filing No. 1 which directs flows to the Harmony Village
Mobile Home Court detention pond. This swale was specifically constructed to handle existing
2 year event runoff from Timberline Farm and will be utilized as a discharge point for a portion
of the developed site runoff.
3.0 Proposed Drainage
The proposed drainage of the site is in accordance with the Master Drainage Report for
Timberline Farm prepared by Engineering Professionals, Inc., dated October 1989. The site will
be divided into 3 basins, denoted A, B, and C as shown on the Final Drainage Plan. Basin A
corresponds to basin 5 of the Master Plan while basins B and C consist of portions of basins
4 and 2, respectively, of the Master Drainage Plan. Calculations are contained in the appendix.
Basin A
Consisting of approximately 5.1 acres, basin A includes the area immediately south of
Caribou Drive which will drain directly onto this street. Runoff from this basin will be directed
to the Sunstone regional detention pond via Caribou Drive. Street capacities for both the 2 and
100 year storm have been calculated to be adequate with this additional flow (refer to
appendix).
Basin B
Basin B is located at the northwest corner of the site and includes 1.5 acres within this
filing and 4.9 acres within the area west of the site to be developed in the future. This basin
will drain to the northwest and will be ultimately be released to the proposed 42" pipe to be
built along the east side of Timberline Road. A detention pond at the southeast corner of
Timberline and Caribou Drive is proposed to handle runoff from this basin. The pond will
restrict flows off the basin to the maximum allowable release rate of 9 cfs (see the Master
Drainage Report for Timberline Farm).
Basin C
Consisting of approximately 20.3 acres, basin C will drain to the northeast into detention
pond 2, sized at 5.2 acre feet. Flows will be directed to the pond by street and storm sewer
flow. Runoff released from the pond, at a maximum rate of 12 cfs, will be directed into the
swale along the south end of Sunstone Filing No. 1 into the Harmony Village Mobile Home
Park detention pond and ultimately into the Sunstone regional detention pond per the Master
Drainage Plan.
Basin and Runoff Data
The following tables identify drainage basin and runoff data for the proposed
development of the site:
DRAINAGE BASIN DATA
BASIN
AREA (acres)
C
Q2 (cfs)
Q100 (cfs)
A
5.1
0.50
4.8
16.9
B1
1.5
0.50
1.7
6.0
B2
4.9
0.20
1.4
4.9
C1
2.6
0.70
4.2
14.6
C2
2.9
0.50
3.7
12.8
C3
4.3
0.50
4.5
15.6
C4
3.0
0.50
3.2
10.9
C5
1.3
0.50
1.6
5.8
C6
0.8
0.50
0.8
2.9
C7
0.8
0.50
1.0
3.6
C8
4.6
0.25
2.1
7.3
C9
0.7
0.20
0.2
0.8
RUNOFF DATA
DESIGN POINT
BASINS
Q2 (cfs)
1
C 1
4.2
2
C1,C2
7.5
3
C1,C2,C4
10.7
4
C1-05
13.4
5
C3
4.5
6
C6
0.8
7
C1-C8
16.9
8
B1
1.7
9
61,132
2.4
10
A
4.8
11
C7
1.0
Q100 (cfs)
14.6
26.4
37.6
47.3
15.6
2.9
59.7
6.0
8.6
16.9
3.6
Detention Pond Data
Sizing calculations for detention pond no.1 are contained in the Master Drainage Report
for Timberline Farm. Calculations for pond no. 2 are contained in the appendix of this report.
The ponds have the folowing characteristics.
Volume Highwater Release Rate
Elev.
Pond No. 1 4,000 cf 4948.9 9 cfs
Pond No. 2 5.2 ac-ft 4947.3 12 cfs
6.0 Conclusion
The Final Drainage Report for Sunstone Village 5th Subdivision was prepared in
accordance with the City of Fort Collins Storm Drainage Criteria and the applicable drainage
master plans for the area. Storm water runoff for the 2 and 100 year storms are routed safely
through the site.
Respectfully Submitted,
ENGINEERING PROFESSIONALS, INC.
Steven L. Kraushaar. P.E.