HomeMy WebLinkAboutDrainage Reports - 01/12/1993swc
Fin4 roved Report
Date 2//2,
Fn'"MRTY OF
FORT c��iLais uTn im
AMENDED OVERALL
DRAINAGE STUDY
FOR
WILD WOOD FARM
)RT COLLINS, COLORADO
AMENDED OVERALL
DRAINAGE STUDY
FOR
WILD WOOD FARM
FORT COLLINS, COLORADO
June 26, 1992
0
Prepared for:
The Architects' Studio
117 E. Mountain Ave. Suite 200
Fort Collins, Colorado 80524
Prepared by:
RBD, Inc. Engineering Consultants
2900 South College Avenue
Fort Collins, Colorado 80525
(303) 226-4955
RBD Job No. 330-003
TMINC.
'
Engineering Consultants
2900 South College Avenue
Fort Collins, Colorado 80525
303/226-4955
'
FAX: 303/226-4971
1
' June 26, 1992
Ms. Susan. Hayes
City of Fort Collins
' Utility Services Stormwater
235 Mathews
Fort Collins, Colorado 80522
RE: Amended Overall Drainage Study for
Wild Wood Farm
' Dear Susan:
' We are pleased to submit to you, for your review and approval, this Amended Overall
Drainage Study for Wild Wood Farm. All computations within this report have been
completed in compliance with the City of Fort Collins Storm Drainage Design Criteria.
We appreciate your time and consideration in reviewing this submittal. Please call if you
have any questions.
Respectfully,
RBD Inc. Engineering Consultants
Roger A. Curtiss, P.E.
Project Engineer
Kevin W. Gingery, P.E.
Project Manager
Other offices: Denver 303/458-5526 • Vail 303/476-6340 • Longmont 303/678-9584
1
TABLE- OF CONTENTS
DESCRIPTION
PAGE
I. GENERAL LOCATION AND DESCRIPTION
1
'
IL DRAINAGE BASINS
A. MAJOR BASIN DESCRIPTION
1
'
III. DRAINAGE DESIGN CRITERIA
A. REGULATIONS
2
tB.
DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS
2
C. HYDROLOGICAL CRITERIA
2
D. HYDRAULIC CRITERIA
2
E. VARIANCES FROM CRITERIA
3
'
IV. DRAINAGE FACILITY DESIGN
A. GENERAL CONCEPT
3
B. SPECIFIC DETAILS
3
V. EROSION CONTROL
A. GENERAL CONCEPT
5
'
VI. CONCLUSIONS
A. COMPLIANCE WITH STANDARDS
5
B. DRAINAGE CONCEPT
6
REFERENCES
6
APPENDIX A
VICINITY MAP
1
'
SWMM DATA FROM THE McCLELLANDS BASIN MASTER DRAINAGE STUDY
2
EXCERPTS FROM THE McCLELLANDS BASIN MASTER PLAN
6
DETENTION REQUIREMENTS FOR THE 1994 JUNIOR HIGH SCHOOL SITE
10
'
ADDITIONAL DETENTION REQUIREMENTS FOR PERMANENT STREETS
18
CHARTS, TABLES AND FIGURES
25
AMENDED OVERALL
DRAINAGE STUDY
' FOR
WILD WOOD FARM
FORT COLLINS, COLORADO
GENERAL LOCATION AND DESCRIPTION
The existing Charter Hospital of Fort Collins and the proposed 1994 Junior High
School site are located within the Amended Wild Wood Farm Overall Development
Plan which occupies the northeast quarter of Section 5, Township 6 North, Range
68 West of the 6th Principal Meridian, Larimer County Colorado, as shown on the
Vicinity Map in the appendix. Wild Wood Farm is bounded on the north by
Harmony Road, on the east by County Road 9, and on the south and west by
undeveloped farmland. The proposed 1994 Junior High School site is to be located
in the southwest portion of Wild Wood Farm. The Junior High School site lies
' within a 45 acre parcel and is planned to eventually contain an Elementary School
and a City of Fort Collins Park. The school site will be bounded on the north by a
proposed local street and on the east by the extension of Corbett Drive. Charter
' Hospital is situated to the north of the proposed school site, on the northwest
corner of the Wild Wood Farm site.
Presently, the undeveloped portion of the Wild Wood Farm site is being utilized for
agricultural purposes. Several irrigation ditches lie within the site. The northerly
ditch adjacent to Harmony Road transports water from west to east through this
property while the other ditches are used for on -site irrigation. The site generally
slopes from the northwest to the southeast at approximately 1 %, while the irrigation
ditches flow primarily from west to east or from north to south. The sequence of
' development for this area must be sensitive to the irrigation ditches as to not cut
off irrigation water to any non -developed land. No information regarding soils type
or groundwater information is known at this time, but should be investigated prior
' to final design.
Ultimate development of the Wild Wood Farm site is planned for a Junior High
School, an Elementary School, parking and access roads for both schools, several
athletic fields, a City of Fort Collins Park, Businesses, Healthcare, Offices, Industry,
and Residential Development on the 138.2 acre site.
I1. DRAINAGE BASINS
A. Major Basin Description
' The site is located in the McClellands Basin. This drainage area is specifically
described in the report entitled McClellands Basin Master Drainage Plan. prepared
by Greenhorn and O'Mara, Inc. 1986. As a part of the Master Plan, a SWMM
model was developed for this basin. A schematic of the SWMM model is included
' in the Appendix. In the SWMM model, this site was modeled as a part of sub -
basin 216 which flows to conveyance element 36 and then 32, and a part of sub -
basin 215 which flows into conveyance element 35. Both conveyance elements 32
and 35 flow to the McClellands Basin Drainageway as do the historic flows from
this site.
Developed flows are to be detained on -site; Charter Hospital, which occupies the
northwest corner of the Wild Wood Farm site, has an existing on -site detention
' pond in place at the southeast corner of the site. Charter Hospital also provided
a temporary detention pond for that portion of Corbett Drive built with that project.
DRAINAGE DESIGN CRITERIA
A. Regulations
All regulations as established by the City of Fort Collins Stormwater Utility
will be used for this Overall Drainage Study.
B. Development Criteria Reference and Constraints
' The McClellands Basin Master Drainage Plan criteria and constraints are
being utilized in this Overall Drainage Study. Drainage criteria not specified
in the McClellands Master Drainage Plans will be in accordance with the
City of Fort Collins Storm Drainage Design Criteria and Construction
Standards Manual. The Master Plan for the McClellands Basin
recommends on -site detention using a staged release rate of 0.20 cfs/acre
' for a 10 year design storm and 0.50 cfs/acre for a 100 year design storm.
C. Hydrological Criteria
' The SWMM hydrological model was used in the McClellands Basin Master
Plan. The SWMM model analyzed the developed flows within the basin with
the ultimate developments in place. A copy of the original SWMM computer
model was not available, so the original SWMM model has not been
updated to include any of the proposed improvements within the Wild Wood
Farm development. The 10 year and 100 year rainfall criteria, which was
obtained from the City, is the criteria which was used for detention pond
' sizing.
D. Hvdraulic Criteria
All calculations within this study have been prepared in accordance with the
1 2
0
1 City of Fort Collins Storm Drainage Criteria.
' E. Variances from Criteria
A variance is being sought for the outfall of storm water runoff from the
' upper portion of developed SWMM Basins 215 and 216 of the McClellands
Basin Master Plan.
IV. DRAINAGE FACILITY DESIGN
tA. General Concept
As development occurs within the Wild Wood Farm site, the drainage
' concepts shown on the Overall Drainage Plan, in the back pocket of this
report, should be followed. A detention pond is planned in the southeast
corner of the 1994 Junior High School Site. An existing detention pond lies
' in the southeast corner of the Charter Hospital Site (Basin B) and
discharges storm water onto Corbett Drive at the required staged release
rate. As development occurs within the Wild Wood Farm, individual basins
' are to have on -site detention ponds with staged release rates to drain
towards the McClellands Basin Drainageway located to the south of the Wild
Wood Farm site.
' B. Specific Details
' A permanent detention pond exists at the southeast corner of the Charter
Hospital site (Basin B) and discharges storm water onto Corbett Drive. A
temporary detention pond exists at the end of existing Corbett Drive.
' Detained runoff leaving the two existing detention ponds currently drains
east across the existing farm land to County Road 9.
' A detention pond is planned near the southeast corner of the Junior High
School site (Basin D), at the southern end of Corbett Drive. This detention
pond is intended to serve the 1994 Junior High School, future Elementary
' School, and future City of Fort Collins Park. Storage provided is based on
the criteria of a release rate of 0.2 cfs/acre for the 10 year storm and 0.5
cfs/acre for the 100 year storm. This on -site detention pond is sized to
' provide storage for the permanent streets on the north and the east side of
the Junior High School site, as well as the remainder of Corbett Drive from
the Junior High School site to Harmony Road (Basin F).
' The existing detention facility for Charter Hospital contains a staged release
mechanism for the 10 and 100 year storm events. The temporary pond at
the south end of Corbett Drive can be eliminated as Corbett Drive is
1 3
J
extended south to the proposed Junior High School as those street flows
will be detained in the school detention pond. Storm water runoff from
Charter Hospital is planned to be released onto Corbett Drive and routed
through the Junior High School detention pond. The property between the
proposed Junior High School site and Charter Hospital (Basin C) will be�
required to detain developed storm water runoff and release storm water
onto Corbett Drive at the required staged release rates. So as not to detain
Basins B & C storm water twice, an overflow mechanism should be
' provided in the Junior High School detention pond to pass these off -site
(previously detained) flows through the Junior High School detention pond.
' The F.A.A. method has been utilized to size the detention pond at the
Junior High School site. Pond models were developed for the 10 year and
' 100 year storm events, and are included in the appendix. The detention
pond was sized for the 10 and 100 year storm events for the 45 acre site
of the 1994 Junior High School, future Elementary School, and future City
of Fort Collins Park. In addition the detention pond was sized to detain
developed storm water runoff from the permanent roads as previously
described. The Junior High School site detention pond required size is 4.42
' acre-feet for the 100 year storm event. The detention pond should be built
with one foot of freeboard and an emergency overflow mechanism.
' From the McClellands Basin Master Plan, the western portion of the Wild
Wood Farm site, west of Corbett Drive, is included in basins 215 and 216
of the SWMM model. Due to timing of proposed development, routing of
basins 215 and 216, to the McClellands Basin Drainageway, is proposed to
be altered with this development. SWMM conveyance element 35, which
was intended to drain basin 215, currently lies in cultivated farm land on
' private property not proposed for development. Along the west property
line of the Wild Wood Farm site, a concrete lined irrigation lateral currently
redirects off -site storm water runoff around the Wild Wood Farm site, and
' southerly towards the McClellands Basin Drainageway.
A variance is being sought for the subject site to modify the upper portions
' of SWMM basins 215 and 216. We have assumed that the existing
concrete irrigation ditch, along the western property line of the site, will
ultimately be an extension of SWMM conveyance element 38, and future
' developed runoff from the upper most portions of basins 215 and 216 will
be routed south to the McClellands Basin Drainageway. Because SWMM
conveyance element 35 cannot be constructed at this time, developed
' storm water runoff from the entire Wild Wood Farm site is proposed to be
routed east to County Road 9, and then south in SWMM conveyance
' element 32 to the McClellands Basin Drainageway. An outlet pipe and open
channel, from the proposed Junior High School site detention pond to
4
1
1
1
1
1
County Road 9, has been shown on the Overall Drainage Plan.
There is an existing roadside ditch at County Road 9 from Harmony Road
to approximately the south property line of the Wild Wood Farm site.
Currently storm water from the Wild Wood Farm site is combined with
irrigation water and routed east under County Road 9 near the south
property line of the Wild Wood Farm site. The combined storm water runoff
and irrigation water continues east through a network of downstream
irrigation laterals. From the south property line of the Wild Wood Farm site,
to the McClellands Basin Drainageway, a roadside ditch does not currently
exist along the side of County Road 9 (SWMM conveyance element
32 ' yet in place .%As development occurs within the Wild Wood. Farm
ite, downstream improvements to the McClellands Basin Drainageway
should be installed to comply with the McClellands Basin Master Plan.
Cp The Wild Wood Farm property lying between Corbett Drive and County
Road 9 (Basins E & G) will be required to detain developed storm water
runoff and release at the multiple rate as previously discussed. The
proposed street from Corbett Drive to County Road 9, through the site, and
the west half of future developed County Road 9, will need to have their
respective undetained storm water runoff accounted for in the adjacent on -
site detention ponds for the proposed developments. Thus these future
street surfaces are being proposed to direct undetained developed runoff
to the McClellands Basin Drainageway with adjacent on -site detention
ponds accounting for the total runoff allowed to leave the sites, as is being
proposed at the 1994 Junior High School site.
y5� EROSION CONTROL
General Concept
GtJ�%dwood Fay.,+
The lies within the Moderate Rainfall Erodibility
Zone and the Moderate Wind Erodibility Zone per the City of Fort Collins
zone maps. Per the City of Fort Collins Erosion Control Reference Manual
for Construction Sites, at the time of final design of the site, the erosion
control performance standard will need to be calculated and appropriate
measures taken to control erosion from the site.
1 VI. CONCLUSIONS
A. Compliance with Standards
All computations within this report have been completed in compliance with
the City of Fort Collins Storm Drainage Design Criteria. A variance is being
1 5
1
I
sought for the outfall of storm water runoff from the upper portions of
developed SWMM Basins 215 and 216 of the McClellands Basin Master
'
Plan.
B. Drainage Concept
'
The proposed drainage concepts adequately provide for detention of
developed runoff from the Wild Wood Farm site. The preliminary size of the
Junior High School site detention pond will enable the Junior High School,
future Elementary School, and future City of Fort Collins Park to develop in
conformance with the McClellands Basin Master Plan for detaining of
'
developed storm water runoff from the site. At the time of preliminary
design, the public street systems should be examined to ensure that they
can transport both the minor and major storm water runoff without
'
exceeding the street capacities. If the street capacities are exceeded for
either storm event, a storm sewer system may be required within the public
'
street system to convey the runoff downstream destinations. Each on -site
detention pond within the Wild Wood Farm site should be provided with 1
foot of freeboard and an emergency overflow outlet in the event the outlet
structure and pipe become plugged. The roadside ditch along the west half
of County Road 9 does not currently allow storm water runoff from the Wild
Wood Farm site to drain to the McClellands Basin Drainageway, as the
downstream property owners are diverting the water for agricultural
purposes. Future improvements to the west half of County Road 9 will
require a roadside ditch to transport 27.6 cfs of storm water (138.2 acres
X 0.2 cfs/acre) during a 10 year storm event and 69.1 cfs of storm water
(138.2 acres X 0.5 cfs/acre) during a 100 year storm event, from the Wild
Wood Farm site to the McClellands Basin Drainageway per the McClellands
' Basin Master Drainage Plan.
IREFERENCES
' 1. Storm Drainage Design Criteria and Construction Standards by the City of Fort
Collins, Colorado, May 1984, revised March 1991.
' 2. Erosion Control Reference Manual for Construction Sites by the City of Fort Collins,
Colorado, January, 1991.
' 3. McClellands Basin Master Drainage Plan, by Greenhorn and O'Mara, Inc., 1986.
4. Master Drainage Study for Wild Wood Farm, by RBD, Inc. July, 1988.
1 6
1
APPENDIX
1
1
1
t
1
1
I
1
1
1
1
VICINITY MAP
NO SCALE rL�T j \ '
I
II
FIGURE 1
[l
SWMM DATA FROM THE MCCLELLANDS BASIN
1 MASTER DRAINAGE STUDY
1
Ll
Z/-/11317 I I RJIIJI\/,
ojcJ _
Timberline CHARTER HOSPITAL
East .
1999
A
HARMONY ROAD
222
22/
NIOR HIGH SCHOOL�IZf
220
/5
Po %JoJV 3/28
WILD W D FARM
+�ircx
I
/6 I o
/07
Z
i°
217 ♦ \
� 2/4
1218 2/3 ~
2/
♦ 12//
1�
ION OF THE SWMM,.HEMATIC
TH c "DS BASIN
2/O�5 �
'"- 201
°tt9 `E4
208 31 •
F
.
...::...:
sUB -.q�?EA
0•9'7"o4
.;•.. -..
EXISTING
FUTURE
SUBAREA
GUTTER
WIDTH
AREA
PERCEPT
PERCENT
SLOPE
'
NUMBER
OR MANHOLE
(FT)
(AC)
1PPERV.
IMPERV
(FT/FTj
;
200
21 ::.
1500:
41.3
5.0 .
30.0
.0200.
'
201
22
920.
21.1
5.0
30.0 .
.0250
202
22
960.
5.5
5.0
30.0
.0160
203
23
1710.
58.8
5.0_
30.0_
.0100
204
23
1650.
34.0
5.0•
30.0
.0200
205
30
3640.
75.3
5.0
32.0
.0100
206
24
1700.
15.6
5.0
34.0
,0230
207
24
2050.
37.6
5.0
53.0
.0180
208
31_
1310.
16.5
5.0
64.0
.0170
209
25
670.
9.2
5.0
70.0
.0100
21",
25
860.
13.8
5.0
30.0
.0080
211
33
3200.
29.4
5.0.
66.0
.0170
212
34.
375.
19.3
5:0
55.0
.0080
213
26
200?.
23.0
�5.0
60.0
.0400
214-
25.
1500.
13.8
5.0
48.0
.0100
35
5920.
135.9
5.0
45.0
.0060.
---i
216::
;:' 36
2100.;
135.0
5.0
50.0
.0100`
217.':
`27
890.
18.4
5.0-
45.0
.0100
'.,.'.
218
27
950.
17.4
5.0:
30.0
.0300
�7
6530.
180.0
5.0.
30.0
.0120
220
28
2640.
.90.9
5.0
36.0
0100
'
22 .`
28
2650.
67.0
5.0
45.0
.0080
2�2
3g
1950.
116.6
5.0.
60.0
.0100
1
80.
4100.
126.7
5.0
45.0
.0113
'
92 :.
2000.
71.5
5.0
45.0
.0100
91
2400:•
59.7
10.0
66.0
.0077
4
82
6600.
196.5
5.0
50.0
.0127
5
90
5520.
8M
5.0
60.0
.0072
6
85
9680.
94.0
5.0
61.0
-.0200'
7
83:.°
3080.
178.7
5,0
47.0
.0156
8
84
1500.
60.8
5.0.
65.0
.0107
'
g
86
340..
15.7
50.0
50.0-
.0076,
10
89
5680.
109.9
62.0 -
62.0
.0076;:..
11
88:::.
3520.
59.6
68.0 :
68.0
.0109.::
12
110
2400.
55.1
.,45.0.
45.0
•'.0077
m cICj_;
'
MASTER
i
La U T. T E R G.4T.9'
S/�s
DTH
INVERT
SIDE SLOPES
Q100
Q00
GUTTER
'`GUTTER
R
DIAM
LENGTH
SLOPE
H0R1Z TO
V_ER_T_
MANNING
Ej(ISTIIG
DEVELOPE
NUF46£R
CONNECTiO
(FT)
(FT)
(FT/FT)
l T
R
N
(CFS).-
(CFS)
20
50
PIPE .
0.1
100.
.oiOO
..Oi
.0
..015
- 1590
1100
21
20
CHANNEL
5.0
1400.
.0057
IS .01
15.0
.045
:650
22
21
CHANNEL
5.0
900.
.0020
20.01
50.0
.015
'630
??
22
CHANNEL
5.0
800.
.0060
150.01
10.0
.045
!620
38
101
23
CHANNEL
5.0
I.
--.0060
150.01
10.0
.045
'i560
910
P4
101
CHANNEL
5.0
1400.
.0038
3.0,
3,0
.045.
330
�5
24
CHANNEL
5.0
1130.
.0030
2.51
2.5
.045.
1330
.C2
25
CHANNEL
5.0
1.
.0100
.2.51
2.5
.045
1310
820
2fi
102_CHANNEL
5.0
1960.
.0100
3.01
3.0
.045
i230
680 .
OVERFLOW
29.0
1960.
.0100
25.01100.0
27
26
CHANNEL
5.0
950.
.0070
1.5j
2.8
.045
230
660
OVERFLOW
31.0
950.
.0070
50.01
50.0
_
.045
27
CHANNEL
5.0
2850.
.0051
3.01
3.0.
.045190
640
CVERFLO;;
17.0
2850.
.0051
80.o'
so.o
.045
29
101
CHANNEL
2.0
1300.
.O11G
100.0,10C.0
.045
+ 37
:!1
29
CHANNEL
i.0
3000.
.0044
200.Oi2U0.0
.045
33
3i
101
%CHANNEL
2.0
1500.
.0150
5.01
5.0
.045
170
113
102
CHANNEL
1.0
255C.-
..0040
25:01
25.0
.045
38
68
3.
31
CHANNEL
7.0
1600.
.0057
70.01
40.0
.045
150
105
�4
102
CHANNEL
_.G
330C.
.006C'
75.01
1.5
.045
5
10 .
3E
102
C A,$ i
1.0
i25P..
.0100
50.0 1
Sri .0
.045
94
63
32
CHANNEL.
I.0
3000.
.0033
25.01
25.0
.045 ..
41
68
_.
3,
CHANNEL
.v
145G.
.00710
150.t 1150.0
.045
130
90
33
27
CHANNEL
2.0
2000.
.006'•
150.01
10.0
.045
34
50
38
ChAh11�L
2 .0
3000.
.COr•/
iC.v1.50.0
.045
_37
58
_
2E
PIPS
:.
4C-:
0100
CI
.0
.015
160
504
2
CHANI;rI
4.0:
2050.
.010E
50.01
60.0
:052
140:
438
80
PIPE'
3 .0
4;.
,0100
.01
.0
.014
81
I 3
81
C A;;tiEl
? ^
- 1.
.003;;
25.01
25.0
.043
420
375
8
103
CHANNEL
2.G
340G:
.0U3G
25.C1
25.0
.04E
205
21E
i<<�
82.
CP.AN'SEL
2.0
-- 1.
.0060
.25.01
'5.0
.048
120
120
;.E3:
',04
UJANNEi
2.0
2000.
'.0075
25.01
25.0
.048
85'
E9
Ee
104
CHANNEL
2.0
2400.
OioC
3.01
3.0
.052
33
30'
E- '
103
CHANNEL
2.0
4600.
.0065
25.01
25.0
.048
112
£F
85
CHANNEL
2.3
800.
.0040
.01
.0
.013.
6�
65
F_7
108
CHANNEL
1.3
720.
.0060
10.01
10.0
.035
88.
108
CHANNEL,
4.0
1020.
.0060
3.01
3.0
.035
332
332
89
109
CHANNEL
2.0
2300.
.0065
25.01
25.0
.052
14
ryF/
x
90
103
CHANNEL
2.0
3000.
.0067
25.01
25.0
.035
71
45
�1
2
CHANNEL
2.0
2400.
.0077
2.0'
2.0
035
51
30
92
2.CHANNEL
2.0
2000.
.0100
2.01
2.0
.035
45
36''
,.10-8
.86
PIPE. :'2.0
50..
.0100
.01
- .0
.013
57
57
,109
88
PIPE.:..
1.8
50.
.0100
01...
.0
.013
1i0
87'PIPE
.<.
1.5
50..
_0100 '
.Gi
.0
.013'
-
GREENHORNE and 0�
MARA
INC::
Designed M R.P
�1e 5.86
Engineers •Architects
Planners Surveyors Photogrommetnsts
Drown By. C.D.s
Date:.5�- 86
I325 South
Colorado Boulevard Suite405 a Denver, Colorado $0222• (303)758-5250
`Checked
By. D J.W
Doter 6. 86
1/70
I
I
EXCERPTS FROM THE MCCLELLANDS BASIN
MASTER PLAN
%e
Historically, land in the basin has been used predominantly for agricultural
purposes. The City is experiencing fairly rapid growth in a southeasterly
direction and development is at various stages in much of the basin.
Residential and light commercial development has already been completed in the
portion of the basin north of Harmony Road.
Significant features influencing drainage patterns in the McClellands Basin
include the Larimer County No. 2 Canal, the Union Pacific Railroad and the
FCRID. The Larimer County No. 2 Canal, which follows a somewhat irregular
alignment east of College Avenue, defines the western limit of the McClellands
Basin. The Union Pacific Railroad is an important feature because significant
' storage potential is created upstream of the relatively high railroad
embankment. The FCRID cuts across the historic McClellands Basin drainageway
about 0.5 miles west of Interstate 25 and presently intercepts storm water runoff
from the basin, conveying it south to Fossil Creek Reservoir.
Summary of Basin Master Plan
Incorporation of on -site detention measures into all new development plans for
the McClellands Basin was the approach utilized to evaluate and develop a master
drainage plan for the basin. Within the McClellands Basin, the maximum release
rate of stormwater from detention storage was established during this study as
equal to 0.5 cfs per acre of drainage area for the 100-year storm event below
Harmony Road. This release rate approximates the average 100-year historic
' runoff rate from the basin as a whole. Above Harmony Road, flow rates were taken
from the Cornell Study since proposed basin improvements have been constructed.
Below Harmony Road, proposed improvements to the drainageway and road crossing
structures were sized to convey runoff at a rate equal to 0.5 cfs per acre of
' drainage basin above a given point in the system. Consequently, it is required
that all runoff from developed areas pass through a detention structure prior to
' being discharged to a drainageway. These provisions will keep peak runoff rates
to a manageable level and 'provide a consistent basin -wide approach for storm
water planning and management.
The overall plan of storm drainage improvements to the McClellands Basin entails
' construction of grass -lined trapezoidal channels capable of conveying the
3
100-year developed discharge, in combination with improved culvert crossings at
all major roads. Several channel drop structures are also incorporated in the
plan to develop acceptable hydraulic conditions in
the grass -lined channels.
Map
1 provides an inventory of channel improvements,
road culvert crossings
and
detention storage facilities in the McClellands
Basin, constructed under
the
basin master plan. Since this inventory will be
updated as improvements
take
place, the City of Fort Collins Storm Water Utility
should be contacted to obtain
the most up-to-date version of this map. Sheet 1, contained in the Appendix,
indexes the plan and profile sheet numbers on
which preliminary design
and
floodplain information can be found. All proposed channel and road crossing
improvements were sized in accordance with criteria set forth in the City of Fort
' Collins Storm Drainage Design Criteria manual.
The total estimated cost to complete the recommended master plan improvements in
the lower portion of the McClellands basin between the FCRID and Timberline Road
equals $2,138,000. Upstream of Timberline Road, Cornell estimated the total cost
' of the recommended master plan improvements to equal $926,150 (1980 Costs).
Detailed cost information and a breakdown of items included in the overall cost
estimate can be found in the Technical Addendum to this report, copies of which
are available at the City of Fort Collins Storm Water Utility.
It should be emphasized that the master drainage plan set forth in this report
relates to future developed conditions with on -site detention. During the period
prior to completion of the required system improvements, the Storm Water Utility
should be contacted to determine if any special interim storm drainage criteria
' are in effect.
' IMPROVEMENTS
General
Three major catagories of drainage improvements are proposed under the master
drainage plan developed for the McClellands Basin: 1) detention storage, 2)
channelization and 3) hydraulic structures. The following sections discuss the
design data utilized and the specific considerations given to each of these
components of the drainage system. Proposed improvements are presented on Sheets
1 through 11, contained in the Appendix. It should be noted that master plan
4
I
improvements proposed by Cornell and shown on Sheets 6 through 9, correspond to
flowrates which have been revised for this study. Consequently, master plan
improvements shown on the aforementioned sheets should be reviewed and revised as
necessary to convey the updated flowrates.
Detention Storage
As discussed previously, on -site detention of storm water is a fundamental
' requirement in the stormwater management plan for the McClellands Basin. New
development within the basin must provide on -site detention facilities with
sufficient capacity to store the 100-year runoff for developed conditions in
excess of the maximum allowable release rate of 0.5 cfs per acre of land.
' Detention facilities must also be sized to detain the 10-year runoff with a
maximum allowable release rate of 0.2 cfs per acre corresponding to this event.
Since proposed improvements to the drainageway and road crossings have been sized
to this rate of release from storage, it must not be exceeded. Development that
has already taken place north of Harmony Road has incorporated sound drainage
practices and presently meets the aforementioned criteria.
Channelization
Due to the relatively undeveloped nature of the McClellands Basin, right-of-way
was not assumed to constrain channel improvements. Although they require a
greater right-of-way, grass -lined channels provide for a more natural appearance
than lined channels. Topography and hydraulic characteristics are also conducive
to use of a grass lined trapezoidal channel shape for the improved drainageway.
Such a concept is consistent with improvements that have already been made to the
drainageway north of Harmony Road.
Table 1 summarizes the channel properties required for conveyance of the 100-year
developed flows with on -site detention. Mannings equation was utilized to
determine the required channel size for a design flow depth limited to four feet.
Channel slope was evaluated considering the existing channel configuration and
surrounding topography, road crossings, and the need to limit flow velocities to
b7
u
1o1zo
I
I
1
DETENTION REQUIREMENTS FOR THE
1994 JUNIOR HIGH SCHOOL SITE
RMING
CLIENT) I�OJC= 11aITEG'TS T �1 o JOB NO. PROJECT _I 4 �SJ_AJ I.OIC 111�tJ CALCULATIONS FOR <Cc�,IMA p n � K
Engineering Consultants MADEBY RJL DATE 6•w•%CHECKED BY DATE SHEET P OF ZF
r=n,aT wEsr. S-reF�r 1
I r,.n Pa2vl�s sue%c'= I.41 �
--PASKE'T'UC>.t.1_. GOL_De�"S
S � D EIfJ�S,
�GTI VE 'eE�.Q.EdTIoi.SpL, lJC �
;CINGl-u�ES SOFT�L.4..., F*�T.E,O.l1.
p�.p rc , L._t��✓ ti15 , � o n cn �D
a as I.34�
%. 23 Ae-1. 0: sS
z13.31 t� o. ZS -7, dtae//_
= 0.41� -..
yz. V---QF_=rsT)
UsSo.slf�c� Ye. �v�rl
I.00 �o �z� 1.zsCoo Yet
I
G
T:IDINC
Engineering Consultants
CLIENT -�•11,I�J+,�Z..I�'.b:ITEr'"r5 "7-'i_)pLp JOB NO:��-�
PROJECT �Y4 qpL� 1 CALCULATIONS FOR ,1 -�'1'�c\iTl/�t� C KTN
MADE BV_E�(_'_DATE CHECKED BVDATE SHEET 1? OF Za
199�- JuL..tloe .t�aC�u �+aoc_ - ��r.EaiTioi.L P�c�ui�.i..�cw11"S
�l1GGLELLZl L?„ose DP�ILJOC�E Pto>\l _-._
yy
.. I
.. i
� a
MdkIMUM r\1 I-pV n,.e>t E Q�I c�c� 2bTe5
-T I M E p1= J�.l CcNT2�T1O1�1 '
"a, I
CxC�� Ic�oYe = o•S�
IL
Z�•nn I w.l .
�.31
T� Cicx�Ye� _ (.87 l• I -a,S(> �_ /z _ .ZZ.� t��l�.l.
I , 31 pis
�/ G2OS5 SJ--4p�T �».OSS �- LAL1.t t�1S r�
�2vrr =1vue� 3 Z VCL x -rY
C%ZS LP� I.O F� _ 7 _=.ea
S EL'
IZ
Tc Cloo vm = Zz + IZ 34• m /�.1 .
T:ADINC
Engineering Consultants
CLIENT +�-'<PCI�I-ITS �TT»1 JOB N0.3'7-O�?�
PROJECT /LJ.1-.�. CALCULATIONS FOR tl_t- CVt4 � KA
MADEBY � DATE4).M CHECKED BV DATE SHEET 13 OF ZE
---------- ---
I
i- I.JS I l�lC� i1Zp-no r.1L1.1_ �t�� MUI_.v C • ��' • .I .- d � _ - _ �
b Y2, L1 'Ca F = 0.41 �x3 i,n,.,_L
CDEvEL OPED�
�/.1TETJSIT"/ Z;4--'MIrj. I1J /14-Z• -..
{�LZ1UBTm>=>`tr 1=�rc�es �L> 1=eo�v, �IC�UIZ-E 1
IL Flo 1-1/e.�
O Z
o- 91 1�%>=rEzrnl rJ I r.IC� D�rE=*vno� ��o
�f=QUI �EMEvTS
r
DETENTION POND SIZING BY FAA METHOD
DEVELOPED BY
JAMES C.Y. GUO, PHD, P.E.
DEPARTMENT OF CIVIL ENGINEERING
UNIVERSITY OF COLORADO AT DENVER
' EXECUTED ON 06.17.1992 AT TIME 11:16:03
PROJECT TITLE: 1994 JUNIOR HIGH SCHOOL SITE DETENTION POND MINOR STORM
** DRAINAGE BASIN DESCRIPTION
BASIN ID NUMBER = 1.00
BASIN AREA (acre)= 45.00
RUNOFF COEF 0.41.
DESIGN RAINFALL STATISTICS
DESIGN RETURN PERIOD (YEARS) = 0.00
INTENSITY(IN/HR)-DURATION(MIN) TABLE IS GIVEN
�URATION 5 10 20 30 40 50 60 80 100 120 150 180
INTENSITY 5.7 4.4 3.2 2.6 2.2i 1.9r 11 1.3� I'1 0.9 0.8 0.6
***** POND OUTFLOW CHARACTERISTICS:
MAXIMUM ALLOWABLE RELEASE RATE = 9 / CFS
OUTFLOW ADJUSTMENT FACTOR = .92'
AVERAGE RELEASE RATE = 8.28 CFS
AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR.
**** COMPUTATION OF POND SIZE
.....................................................
RAINFALL RAINFALL INFLOW OUTFLOW REQUIRED
DURATION INTENSITY VOLUME VOLUME STORAGE
MINUTE INCH/HR ACRE -FT ACRE -FT ACRE -FT
.....................................................
0.00 0.00 0.00 0.00 0.00
5.00 5.70' 0.73✓ 0.00.67�
10.00 4.40/ 1.13-l' 0.11-,' 1.01"
15.00 3.82 1.47✓ 0.17.- 1.30'
20.00 3.24' 1.66�' 0.23-' 1.43''
25.00 2.92 1.87, 0.29�' 1.59�
30.00 2.60/ 2.00✓ 0.34-� 1.66-'
35.00 2.39 2.14`- 0.40-' 1.74-
40.00 2.18- 2.23� 0.46V 1.7V
45.00 2.02 2.33- 0.51' 1.82r
50.00 1.86 / 2.38✓ 0.57' 1.81 ✓
55.00 1.74 2.45✓ 0.63 1.83'
60.00 1.62 ' 2.49✓ 0.68 - 1.81/
65.00 1.54 2.57✓ 0.74- 1.821
70.00 1.46 2.62✓ 0.80� 1.82,
75.00 1.38 2.65-f 0.86- 1.80/
80.00 1.30/ 2.67� 0.91 / 1.75/
85.00 1.22 2.66 0.97., 1.69,
A....................................................
HE REQUIRED POND SIZE = 1.82504' ACRE -FT
HE RAINFALL DURATION FOR THE ABOVE POND STORAGE= 55 MINUTES
0
i
15/z6
I
***** GEOMETRIES OF AN EQUIVALENT CIRCULAR POND
STAGE
CONTOUR
CONTOUR
POND
POND
(DEPTH)
DIAMETER
AREA
SIDE SLP
STORAGE
FEET
FEET
ACRE
FT/FT
ACRE -FT
.....................................................
0'00
166.53
0.50
3.00
0.00
0:50
169.53
0.52
3.00
0.25
1.00
172.53
0.54
3.00
0.52
1.50
175.53
0.56
3.00
0.79
2.00
178.53
0.57
3.00
1.07
2.50
181.53
0.59
3.00
1.37
3.00
184.53
0.61
3.00
1.67
3.50
187.53
0.63
3.00
1.98
'4*00
....................................................
190.53
0.65
3*00
2.30
I
Mize
DETENTION POND SIZING BY FAA METHOD
DEVELOPED BY
JAMES C.Y. GUO, PHD, P.E.
DEPARTMENT OF CIVIL ENGINEERING
UNIVERSITY OF COLORADO AT DENVER
--------------------------------------------------------
EXECUTED ON 06-17.1992 AT TIME 11:14:22
PROJECT TITLE: 1994 JUNIOR HIGH SCHOOL SITE DETENTION POND MAJOR STORM
t** DRAINAGE BASIN DESCRIPTION
BASIN 1D NUMBER = 1.00
BASIN AREA (acre)= 45.00
RUNOFF COEF 0.51 z
***** DESIGN RAINFALL STATISTICS
DESIGN RETURN PERIOD (YEARS)
INTENSITY(IN/HR)-DURATION(MIN) TABLE IS GIVEN
�URATION 5 10 20 30 40 50 60 80/ 100 120 150 180
INTENSITY 9.0/ 7.3' 5.2 4.Z- 3.5 3.0 2.6- 2.1 1.-r 1.5 12 1.0
POND OUTFLOW CHARACTERISTICS:
MAXIMUM ALLOWABLE RELEASE RATE = 22.5 CFS
OUTFLOW ADJUSTMENT FACTOR = .91/
AVERAGE RELEASE RATE = 20.475' CFS
AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR.
F**** COMPUTATION OF POND SIZE
-----------------------------------------------------
RAINFALL
RAINFALL
INFLOW
OUTFLOW
REQUIRED
DURATION
INTENSITY
VOLUME
VOLUME
STORAGE
MINUTE
INCH/HR
ACRE -FT
ACRE -FT
ACRE -FT
0.00
0.00
0.00
0.00
0.00
5.00
9.00-
1.43
0.14
1.29
10.00
7.30
2.33
0.28
2.04
15.00
6.25
2.99
0.42
2.57
20.00
5.20•
3.32
0.56
2.75
25.00
4,68
3.73
0.71
3.02
30.00
4.15✓
3.97
0.85
3.12
35.00
3.83
4.27
0.99
3.28
40.00
3.50,'
4.46
1.13
3.33
45.00
3.25
4.66
1.27
3.394*--
50.00
3.00 �
4.78
1.41
3.37
55.00
2.80
4.91
1.55
3.36
60.00
2.60
4.97
1.69
3.28
65.00
2.46
5.10
1.83
3.27
70.00
2.32
5.19
1.97
3.21
75.00
2.19
5.23
2.12
3.11
THE REQUIRED
POND SIZE
= 3.392607 ACRE -FT
HE RAINFALL DURATION FOR THE ABOVE POND STORAGE= 45 MINUTES
I
I
ADDITIONAL DETENTION REQUIREMENTS
IFOR PERMANANT STREETS
It
I
***** GEOMETRIES OF AN EQUIVALENT CIRCULAR POND
STAGE
CONTOUR
CONTOUR
POND
POND
(DEPTH)
DIAMETER
AREA
SIDE SLP
STORAGE
FEET
FEET
ACRE
FT/FT
ACRE -FT
.....................................................
0.00
166.53
0.50
3.00
0.00
0.50
169.53
0.52
3.00
0.25
1.00
172.53
0.54
3.00
0.52
1.50
175.53
0.56
3.00
0.79
2.00
178.53
0.57
3.00
1.07
2.50
181.53
0.59
3.00
1.37
3.00
184.53
0.61
3.00
1.67
3.50
187.53
0.63
3.00
1.98
4.00
190.53
0.65
3.00
2.30
4.50
193.53
0.68
3.00
2.63
5.00
196.53
0.70
3.00
2.98
5.50
199.53
0.72
3.00
3.33
6.00
202.53
0.74
3.00
3.70
6.50
205.53
0.76
3.00
4.07
.....................................................
7.00
208.53
0.78
3.00
4.46
CLIENT �eG�-•�'ITEC'-T� �TLJpto JOB NO. B:a'C> 3
T:AD,NC� J' PROJECT I'C h4ICM_- t1IC_y CALCULATIONS FOR_DF-:TIE-� CT ,o J D�^1 tTS
Engineering Consultants MADEBY E51_1 DATE6.1_9zCHECKED BY- DATE SHEET 19 OF 28
� � ni nl �L.d�oisS Foz-dDD�Tlor�lc�_ 7ET��.ITotJ �EQuie�i.,��i.ii'S� -fie. _ l
I
Mp __l r.l_..... f4: - JUNi loEt:. l�_ .sc��: DEr�u ion:+ 'F�*►
PL TUe E ST�E�T i=�c r Er.ITfoc.l I
C�,F C.a�L.1 .tT y��,1VE. _A�ZyJL1GEh.IT To
CurEST % Dy ��� 1�1TE=D >=02 i I\1 51 rE ->'ET�Tl N
G172.6E7T pF S crT , C Tb �DCse= ...c)F E)CIST. .pS 1'�• LIOLT1
moo+ IZX�Fo� = 3348c�SF /
+- (D.8Z C->2„��-+_ �,ds, 1>=1 - CyaarLTt=S2 E4c�s�JT��
�97
F=F,
+ 4. S3 49. S3
�Ti-mc oc= C�Ia�J�'e.�Tc�l
Is 11v sre ✓Er rto av'=v �� Ra�ei`
1- 7:E5 1 ZoC) = 29-t.F=
CLIENT-AE- - I-r�T-'' 11�7"77A10 JOB NO.
J�
T:§D,NC PROJECT P94 11� 441 U CALCULATIONS FOR ITI0,1.1
Engineering Consultants MADEBYF-,"_DATEk-t-I CHECKEDBV DATE SHEET ZO OF ZB
Don�oa.c>-- �E'T'E�.tnor.i 'P��L�ie-ET�.)r�t-rS Fort . P��MbtJ."iitr-ST2EET5
onJ-r 1.luao�)
tvt1k. �n�TFt Z97 ^
1. S l...Y Z 4p
TIM--.._.,E - .DP___
G:OIJG��1T2.oTlol.15 L��tEP1.) .. �
f=O P-Mt.k� Q . C - L' _ • .4 _
V1++E�E C• GIB a• 4b' to ye.
a. I cx:> ire
cm: 38 rn1�
3.9c> Iij /t+2 Ct�`/tz4M
. _ � = C� • 4C��C.Z . ZS�C49. 53�. _ � I . Zro� C.Lo %�� -
C
Sx 4!= S = Z4 .-7-7✓cC
. _A jL_�STIv-1F_--t.IT- (Z) I
Pere_ o•.r .91
Q 1�J7=.0L-- Ir.S .ZC�
Z4
IIZ-04
I! C(o �e.� = 0-9
L CI oo ti2) - o .9z
CIo
a• -Z Clod Yam)
DETENTION POND SIZING BY FAA METHOD
DEVELOPED BY
JAMES C.Y. GUO, PHD, P.E.
DEPARTMENT OF CIVIL ENGINEERING
UNIVERSITY OF COLORADO AT DENVER
EXECUTED ON 06-17-1992 AT TIME 13:37:39
PROJECT TITLE: 1994 JUNIOR HIGH SCHOOL DETENTION PONDS WITH ADDITIONAL CAPACITY FOR PERMANANT STREETS
9** DRAINAGE BASIN DESCRIPTION
BASIN ID NUMBER = 1.00 .
BASIN AREA (acre)= 49.53/
RUNOFF COEF 0.46i
***** DESIGN RAINFALL STATISTICS
DESIGN RETURN PERIOD (YEARS) = 10.00/
INTENSITY(1N/HR)-DURATION(MIN) TABLE IS GIVEN
URATION 5 10 20 30 40 50 60 80 100 120 150 180
INTENSITY 5.7-4.4' 3!2 2:6 2 2 -1.9 1:6 1:3 1:1 0 9 0:8 0 6
***** POND OUTFLOW CHARACTERISTICS:
MAXIMUM ALLOWABLE RELEASE RATE = 9.91 • CFS
OUTFLOW ADJUSTMENT FACTOR = .93_
AVERAGE RELEASE RATE = 9.2163 ' CFS
AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR.
**** COMPUTATION OF POND SIZE
RAINFALL
RAINFALL
INFLOW
OUTFLOW
REQUIRED
DURATION
INTENSITY
VOLUME
VOLUME
STORAGE
MINUTE
INCH/HR
ACRE -FT
ACRE -FT
ACRE -FT
0.00
...........................................
0.00
0.00
0.00
0.00
5.00
5.70
0.90
0.06
0.84
10.00
4.40
1.39
0.13
1.27
15.00
3.80
1.80
0.19
1.61
" 20.00
3.20
2.03
0.25
1.77
25.00
2.90
2.29
0.32
1.98
30.00
2.60
2.47
0.38
2.09
35.00
2.40
2.66
0.44
2.21
40.00
2.20
2.78
0.51
2.28
45.00
2.05
2.92
0.57
2.35
50.00
1.90
3.01
0.63
2.37-w-
55.00
1.75
3.05
0.70
2.35
60.00
1.60
3.04
0.76
2.28
65.00
1.52
3.14
0.83
2.31
70.00
1.45
3.21
0.89
2.32
75.00
1.38
3.26
0.95
2.31
80.00
1.30
3.29
1.02
2.28
01HE REQUIRED POND SIZE .3714 ACRE -FT
HE RAINFALL DURATION ABOVE POND STORAGE= 50 MINUTES
c
2Z/Zg
i
***** GEOMETRIES OF AN EQUIVALENT CIRCULAR POND
•-------------------------•-•-------------•-•••-•
STAGE
CONTOUR
CONTOUR
POND
POND
_! (DEPTH)
DIAMETER
AREA
SIDE SLP
STORAGE
FEET
FEET
ACRE
FT/FT
ACRE -FT
.....................................................
0.00
166.53
0.50
3.00
0.00
0.50
169.53
0.52
3.00
0.25
1.00
172.53
0.54
3.00
0.52
1.50
175.53
0.56
3.00
0.79
2.00
178.53
0.57
3.00
1.07
'
2.50
181.53
0.59
3.00
1.37
3.00
184.53
0.61
3.00
1.67
3.50
187.53
0.63
3.00
1.98
4.00
190.53
0.65
3.00
2.30
4.50
193.53
0.68
3.00,
2.63
5.00
196.53
0.70
3.00
2.98
1
2 3/Zo
DETENTION POND SIZING BY FAA METHOD
DEVELOPED BY
�1 JAMES C.Y. GUO, PHD, P.E.
DEPARTMENT OF CIVIL ENGINEERING
UNIVERSITY OF COLORADO AT DENVER
EXECUTED ON 06.17-1992 AT TIME 13:39:36
,i i
PROJECT TITLE: 1994 JUNIOR HIGH SCHOOL DETENTION POND WITH ADDITIONAL STORAGE PROVIDED FOR PERMANANT STREETS
I** DRAINAGE BASIN DESCRIPTION
BASIN ID NUMBER = 1.00
BASIN AREA (acre)= 49.53'�
RUNOFF COEF 0.58-'
***** DESIGN RAINFALL STATISTICS
DESIGN RETURN PERIOD (YEARS) 6-
100.00
INTENSITY(IN/HR)-DURATION(MIN) TABLE IS GIVEN
URATION 5 10 20 30 40 50 60 80 10D 12D 15D 180
INTENSITY 9.0-7S 5 2- 4 2 3:5 3:0 2 -6 2.1 1.7 1.1 1.2 1.0
n
**** POND OUTFLOW CHARACTERISTICS:
/ MAXIMUM ALLOWABLE RELEASE RATE = 24.77 /CFS
1 OUTFLOW ADJUSTMENT FACTOR = .92.
AVERAGE RELEASE RATE = 22.7884 CFS
AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR.
i
**** COMPUTATION OF POND SIZE
........................
,RAINFALL RAINFALL INFLOW OUTFLOW REQUIRED
DURATION INTENSITY VOLUME VOLUME STORAGE
MINUTE INCH/HR ACRE -FT ACRE -FT ACRE -FT
0.00 0.00 0.00 0.00 0.00
5.00 9.00 1.80 0.16 1.64
10.00 7.30 2.91 0.31 2.60
15.00 6.25 3.74 0.47 3.27
20.00 5.20 4.15 0.63 3.52
25.00 4.70 4.69 0.78 3.90
30.00 4.20 5.03 0.94 4.09
35.00 3.85 5.38 1.10 4.28
40.00 3.50 5.59 1.26 4.33
45.00 3.25 5.84 1.41 4.42
50.00 3.00 5.98 1.57 4.42
55.00 2.80 6.14 1.73 4.42
60.00 2.60 6.22 1.88 4.34
65.00 2.47 6.42 2.04 4.38
70.00 2,35 6,56 2.20 4.37
75.00 2.22 6.66 2.35 4.30
...............................................•.....
THE REQUIRED POND SIZE - 4 47� ACRE FT
HE RAINFALL DURATION F� BOVE POND STORAGE= 45 MINUTES
Z%l
11
***** GEOMETRIES OF AN EQUIVALENT CIRCULAR POND
1**('D-E*P-T-H)--D-IAMETER
STAGE
.................•--••----------------
CONTOUR
CONTOUR
POND
POND
AREA
SIDE SLP
STORAGE
FEET
FEET
ACRE
FT/FT
ACRE -FT
0.00
166.53
0.50
3.00
0.00
0.50
169.53
0.52
3.00
0.25
1.00
172.53
0.54
3.00
0.52
1.50
175.53
0.56
3.00
0.79
2.00
178.53
0.57
3.00
1.07
2.50
181.53
0.59
3.00
1.37
3.00
184.53
0.61
3.00
1.67
3.50
187.53
0.63
3.00
1.98
4.00
190.53
0.65
3.00
2.30
'
4.50
193.53
0.68
3.00
2.63
5.00
196.53
0.70
3.00
2.98
5.50
199.53
0.72
3.00
3.33
6.00
202.53
0.74
3.00
3.70
6.50
205.53
0.76
3.00
4.07
7.00
208.53
0.78
3.00
4.46
7.50
211.53
0.81
3.00
4.85
8.00
214.53
0.83
3.00
5.26
8*50
217.53
•.....
0.85
....
3.00
•...
5.68
----
,I
254b
CHARTS, TABLES AND FIGURES
26129
DRAINAGE CRITERIA MANUAL RUNOFF
i.
'
S0
I
30
20
z
W
U
Q
W
a
10:
z
a
JO.
5
Vl
W
3
O
U
?W
Q
3
1
5
MMNNINII�AjEVANFANIMM
FA FA I
M
���I
III
■I,I
■�/�������■■�
.1 .2 .3 .5 1 2 3 5 10 20
VELOCITY IN FEET PER SECOND
FIGURE 3-2. ESTIMATE OF AVERAGE FLOW VELOCITY FOR
USE WITH THE RATIONAL FORMULA.
*MOST FREQUENTLY OCCURRING "UNDEVELOPED"
LAND SURFACES IN THE DENVER REGION.
REFERENCE: "Urban Hydrology For Small Watersheds" Technical
Release No. 55. USDA. SCS Jan. 1975.
5 -1-84
ROAN DRAINAGE d FLOOD CONTROL DISTRICT
I
No Text
s
1
1
1
1
1
1
1
1
1
1
1
1
1
1
c
r
c
c�
c
Lr
c
c
K
c
c
c
c
c
00 (0 d N ' 00 Qo --r EN o0
' O 00 00 00 00 O
O O O O O O O O
' x — .zo-}a-eJ -4uaTM snfpv Moulnp
�`
p
O w
0
4w .� .
41
aL) a)
a 4J
�cr n
O �
4J
Q' 3
cr 0
.1 .1
w
41
J :j
0
11
.r,Gwo
rtnM,!aPH rurH
! eo.• H I!, mlappn:vl
I9 hF l i CFM n� N P¢OPSmD CWJ1NEl
y.Ij.re TD W. ROAD 9
Po'FMbIDE 01214
LXIST �KM fYJIIDINGS � � .f.Rw•923 Cfh -
�D2.AE
1
INvuSIRIAL�BU51NE55 PARK °AIGLE FAMEL
w/OM sl'E DETEHT!ON FE510EIJTAEw'
'oN51'E ^EILK'.t:Ln;
P PIMD IIIETS
5TMCM SOUVO
453PG PT Low PT
65PAIJ--. - 0 R VE —
PM1OP05EVDETERH fWD
0 nt,vlJ WL MO'P •4p LAG CT
i III
1.1A♦ r.,M1 .11V Ai
4SoD4C P11CM E0 I'44
0IOR NI(y1 WL
E WITH WNRE
ELtMENISNAY SCL:4.
t C aF FOK"
E%ISHJp IRFILATInN
91'JERI 10H anVlrsl
�-`
IPROVO%O L
Ili GLIP5IP'.p L. ��� P�rflrfff
I �� - 1 I i..��aloewr*' • a
'P' r V I '
'
•.a +� +C� q
E M% tY
Ex15rIUCG a OUTLET ex% CA.LI115 PARK
OEM DETEIITIOxI G PIPE
I POMD
�I1 IL
I ,uJISI%mFE591UIJAL OCHARTER ON-51TE DETEI EX15TI J PSKILAT ON LATECAL
w�
._
•_ -"^.--
"y !' MASTER DRAINAGE 6DV. _� _q
NOTE
I. POND AREA IS SCHEMATIC p"LY, ILEGEND
AND COULD CNANOE IN SIZE OFFSITE STORM WATER RUNOFF
DEPENDING ON DEPTH 1 eOHOM 3LOPE5. 15 CURRENTLY MW TED SOUTH
j DY THE eXPIT144 CONCRETE Q MSIN CESILNATION
IRRIGATION LATERAL.
LL bPSIN A(AEPGE
GMAINAGE KW PIRECTIOM
9A4AM ?OUMOART
EHSIII.IG CONTOUR
ONpV. SI
__ UESILNEU CHECKED Engineering Consultants
:L-92 RRV15E0 INTERNAL STREETS DETENTION POM i90-0O5 1Ll eR IM00 S.mn r. u_`m.I.d.8zsixa. snlaot
bTE REVISION DESCRIPTION APPH'VEH DALE PItOIECT NU. Fill IOI,}In—t955 C.1110(16805]5 f-6140
a
SCALEI•I 2W'
WILD WOOD FARM
Y
N....w,... I ......,...
ro
—xwaolda'•4 zr � \ i
zia rIIfi \zu db .��.
zoe
N9 _
A TION NF THE WMM NEMATIC F
JUN 26 tW2 , TH P NDSBASIN
5:A5/P
SHEETS SHEET
OVERALL DRAINAGE PLAN