HomeMy WebLinkAboutFALCON RIDGE PUD - PRELIMINARY - 2-94F - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTFALCON RIDGE, P.U.D.
THE MASS DIAGRAM FOR THE DETENTION BASIN
70
60
w
50
U
l� y 40
D
C
fd
U N
0
r
30
O
T
20
O
O
10
0
5.0 10.0 15
.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 55.0 60.0 70.0 80.0 90.0 100.0 110.0 120.0 135.0 150.0 165.0180.00
TIME IN MINUTES
rt - Total Runoff Vol. 00 Allowable Discharge Vol.
NOTE: Discharge plot does not appear linear since time are not uniformly spaced
THIS MASS DIAGRAM TABLE IS FOR USE IN ESTABLISHING THE STORAGE VOLUME
REQUIRED FOR THE 100 YR. STORM EVENT
FALCON RIDGE, P.U.D.
0.45 = Runoff (c) 10.00 = Area (acres) 2.60 = Release Q(2)***
TIME
(min)
INTENSITY
(in/hr)
C*Cf*A
(sq.ft.)
RUNOFF
(cu/ft)
OUTFLOW
(cu/ft)
STORAGE
(cu/ft)
5.0
7.00
5.63
11812.5
780.0
11032.5
10.0
7.00
5.63
23625.0
1560.0
22065.0
15.0
6.10
5.63
30881.3
2340.0
28541.3
20.0
5.20
5.63
35100.0
3120.0
31980.0
25.0
4.68
5.63
39487.5
3900.0
35587.5
30.0
4.15
5.63
42018.8
4680.0
37338.8
35.0
3.83
5.63
45241.9
5460.0
39781.9
40.0
3.50
5.63
47250.0
6240.0
41010.0
45.0
3.25
5.63
49359.4
7020.0
42339.4
50.0
3.00
5.63
50625.0
7800.0
42825.0
55.0
2.80
5.63
51975.0
8580.0
43395.0
60.0
2.60
5.63
52650.0
9360.0
43290.0
.0.0
_ <:2 33
5 63
55046 3
10920 0'
44126.3'.
80.0
2.05
5.63
55350.0
12480.0
42870.0
90.0
1.88
5.63
57105.0
14040.0
43065.0
100.0
1.70
5.63
57375.0
15600.0
41775.0
110.0
1.58
5.63
58657.5
17160.0
41497.5
120.0
1.45
5.63
58725.0
18720.0
40005.0
135.0
1.33
5.63
60598.1
21060.0
39538.1
150.0
1.20
5.63
60750.0
23400.0
37350.0
165.0
1.13
5.63
62926.9
25740.0
37186.9
180.00
1.05
5.63
63787.5
28080.0
35707.5
*** NOTE: -if C * Cf >= 1 , then C * Cf = 1 is used
4.9
1 0.801 1 520.001 1
0.45 = Runoff C 1.00 = Cf 2,10 1.25 =Cf 100
D. Pnt.
Area
(acres)
C Cf
I (2yr.)
(in/hr)
I (10yr.)
(in/hr)
I (100yr.)
(in/hr)
Basin 0
(cfs
Comb. 0
(cfs)
COMMENTS
M.],.::
1.15
0.45
2.20
4,41
1.
2 yr. runoff
0.45
4.60
2.W
10 yr. runoff
0.56
7.00
100 yr. runoff
0.45 C 1.00 =Cf(zlo) 1.25 =Cf(100)
.,M
D. Pnt.
Area
(acres)
C Cf
I (2yr.)
(in/hr)
I (10yr.)
(in/br)
I (100yr.)
(in/hr)
Basin Q
(cfs)
Comb. Q
(cfs)
COMMENTS
0.75
0.45
270
0.91
Oi
2 yr. runoff
0.45
4.70
1.59
10 yr. runoff
0.56
7.00
.. .... .....
100 yr. runoff
0.45 = C 1.00 =Cf(zlo) 1.25 =Cf 100
-2-9511:.
ILLLqLLLJ
SU BBASI N::::.: O.c 000vr):
:- x
D. Pnt.
Slope
C Cf
Length
(feet)
Overl-Tc
(min.)
Vel.Chan
(ft/sec.)
Tc Chan.
(min.
TcTotal
(min.)
COMMENTS
4.001
0.561
150.001
7.81
Tc (100)
1.401
1 920.001
1 2501
6 1
1391
LNGST.OVER'-+CHANNEL
0.45 = Runoff C 1.00 = Cf 2,10 1.25 =Cf 100
1
D. Pnt,
Area
(acres)
C Cf
I (2yr.)
(in/hr)
I (10yr.)
(in/hr)
I (100yr.)
(i n /h r)
Basin 0
(cls)
Comb. 0
(cfs)
COMMENTS
225
0.45
220
....... 2211
2 yr. runoff
0.45
3.86
3.85
3i81
10 yr. runoff
0.56
6.20
7
100 yr. runoff
0.45 = C 1.00 =Cf(zlo) 1.25 =Cf(100)
.SUBBASIN:,.:Ti O'CLL
..........
D. Pnt.
Slope
C Cf
Length
(feet)
OverLTc
(min.)
Vel.Chan
(ft/sec.)
Tc Chan.
(min.)
Tc Total
(min.)
COMMENTS
3.00
0.56
300.00
121
Tc (100)
1.60
330.00
2.75
20
LNGST. OVERL+CHANNEL
0.45 = Runoff C 1.00 = Cf Z10 1.25 =Cf 100
D. Pnt.
Area
(acres)
C Cf
I (2yr.)
(in/hr)
I (10yr.)
(in/hr)
I (100yr.)
(in/hr)
Basin Q
(cfs
Comb. 0
(cfs)
COMMENTS
L
4.85
0.45
220
4.80 11
2 yr. runoff
0.45
3.80
8.291
.-- �:: -:,:':.:8.3
10 yr. runoff
0.56
6.20
16.91
..... 16a9
100 yr. runoff
0.45 = C 1.00 =Cf(zlo) 1.25 =Cf 100
11
1 = ^I t= kclu) u lis pcly::
D. Pnt.
Slope
0
C Cf
Length
(feet)
Overl-Tc
(min.)
Vel.Chan
(ft/sec.)
Tc Chan.
(min.
Tc Total
(min.)
COMMENTS
2-001
0.56
150.00
9.8
Tc (100)
0.401
430.00
1.50
4.8
...... 14.6.
LNGST. OVERL+CHANNEL
0.45 = Runoff C 1.00 = Cf 2,10 1.25 =Cf 100
D. Pnt.
Area
(acres)
c Cf
1(2yr.)
(in/hr)
I (10yr.)
(in/hr)
I (100yr.)
(in/hr)
Basin Q
(cfs)
Comb. 0
(cfs)
COMMENTS
1.82
0.45
2.15
1.76
2 yr. runoff
0.45
3.80
3 * 111
10 yr. runoff
0.56
6.10
6.24
6.211
100 yr. runoff
0.45 = C 1.00 =Cf(zlo) 1.25 =Cf(100)
D. Pnt
Slope
c Cf
Length
(feet)
Overl-Tc
(min.)
Vel.Chan
(ft/sec.)
Tc Chan.
(min.)
Tc Total
(min.)
COMMENTS
2.00
0.56
50.00
5.6
Tc (100)
0.40
700.00
2.25
5.2
1088
LNGST. OVERL+CHANNEL
U.45 = Hunotr u 1.uu = ut 2,1u 1.25 =L;t 100
D. Pnt.
Area
(acres)
C Cf
I (2yr.)
(in/hr)
I (10yr.)
(in/hr)
I J100yr.)
Cin/hr)
Basin Q
(cfs)
Comb. Q
cfs
COMMENTS
0.88
0.45
2.4o
0.95
',1.0j
2 yr. runoff
0.451
4.20
1.661
10 yr. runoff
0.561
6.80
3.37
..... .... .... 3.4
100 yr. runoff
0.45 = C 1.00 =Cf Z10) 1.25 =Cf (100)
SUBBASIN::::T.O.C.:.:..:.(loovr)::,::�:�����
D. Pnt.
Slope
C Cf
Length
(feet)
Overl-Tc
(min.)
Vel.Chan
(ft/sec.)
Tc Chan.
(min.)
Tc Total
(min.)
COMMENTS
2-501
0.56
480.00
16.2
Tc (100)
1.001
0.00
1.50
0.0
LNGST. OVERL+CHANNEL
0.45 = Runoff C 1.00 = Cf 2,10 1.25 =Cf 100
D. Pnt.
Area
acres )
c Cf
I (2yr.)
(in/hr)
I (10yr.)
(in/hr)
I (100yr.)
(in/br)
Basin Q
(cfs)cfs
Comb. Q
COMMENTS
0.80
0.45
2.10
0.90
2 yr. runoff
0.45
3.55
1.52
10 yr. runoff
0.56
5.70
3.05
. :. 3.0
100 yr. runoff
0.45 = C 1.00 =Cf(zlo) 1.25 =Cf(100)
j.bu = Area(ac) mis page
D. Pnt
Area
(acres)
C Cf
I (2yr.)
(in/br)
I (10yr.)
(in/hr)
I (100yr.)
(in/hr)
Basin Q
(cfs)
Comb. Q
(cfs)
COMMENTS
0.81
0.45
2.60
0 95
0
2 yr. runoff
0.45
4.55
1.66
. ... ..17
10 yr. runoff
0.56
7.00
3.19
32
100 yr. runoff
0.45 = C 1.00 =Cf(zlo) 1.25 =Cf(100)
:SUBBASIN.:,:T (JWVr)',L.:.',:
D. Pnt
Slope
%(min.)
C Cf
Length (feet )
OverLTc
I Vel.Chan
(tt/sec.
Tc Chan.
min.
Tc Total
min.)
COMMENTS
zoo
0.561
330.001
14.5
1
Tc 1w
()
1.001
1 0.001
1 1.50
0.0
LNGST. OVERL+CFIANNEL
0.45 = Runoff C 1.00 = Cf Z110 1.25 =Cf 100
D. Pnt.
Area
(acres)
C Cf
I (2yr.)
(in/hr)
I (10yr.)
(in/hr)
I (100yr.)
OWN
Basin Q
(cfs)
Comb. Q
(cfs)
COMMENTS
1.01
0.45
215
0.98
f OS
2 yr. runoff
0.45
3.80
1.73
10 yr. runoff
0.0.566.10
3. 47
100 yr. ninoff
0.45 = C 1.00 =Cf(zlo) 1.25 =Cf(100)
SUBBASIN T.00.'� 1".: (1
. . ... ..
D. Pnt.
Slope
N
C Cf
Length
(feet)
OverLTc
(min.)
Vel.Chan
(ft/sec.)
Tc Chan.
(min.)
Tc Total
(min.)
COMMENTS
F
2001
0.56
50.00
5.6
Tc (100)
0.901
495.00
2.00
4.1
9.8:1
LNGST. OVERL +CHANNEL
0.45 = Runoff C 1.00 = Cf 2,10 1.25 =Cf 100
D. Pnt.
Area
(acres)
C Cf
I (2yr.)
(in/br)
I (10yr.)
(i n /h r)
I (100yr.)
(in/hr)
-Basin Q
cfs
Comb. Q
cfs
COMMENTS
F ...
0.69
0.45
2.00
0.62
2 r. runoff
y
0.45
4.40
127
...........
10 yr. runoff
0.56
7.00
2.721
27
100 yr. ninoff
0.45 = C 1.00 =Cf(zlo) 1.25 =Cf(100)
Z51 = Area(aC) tnis page
SUBBASIN.:...
DEVELOPED RUNOFF COMPUTATIONS FROM RATIONAL METHOD
0 = C x Cf x I xA
.. ....
D. Pnt.
Slope
C*Cf
Length
OverLTc
Vel.Chan
Tc Chan.
Tc Total
COMMENTS
(feet)
(min.)
(ft/sec.)
(min.)
6.501
0.56
230.00
8.2
-(min.)
Tc (100)
0.401
200.00
.1.50
2.22
_:i 104]
LNG. ST. OVERL+CHANNEL
0.45 = Runoff C
1.00 = Cf 2,10
1.25 =Cf 100
D. Pnt.
Area
(acres)
C Cf
I (2yr.)
Cin/br)
I (I 0yr.)
(in/hr)
I (100yr.)
(iin/br)
Basin 0
cfs
Comb. Q
cfs
COMMENTS
247
0.45
2.45
P-72
7,, ------- -------- - ---- -
.... Z7
2 yr. runoff
0.45
3.50
3.89
11
10 yr. runoff
0.56
4.38
6.09
6.1
100 yr. runoff
0.45 = C 1.00 =Cf(zlo) 1.25 =Cf 100
ILLLLALLLJ
:SUBBASIN: :T O.C.J100yr):
D. Pnt.
Slope
c Cf
Length
OverLTc
Vel.Chan
I Tc Chan.
I TcTotal _F_
COMMENTS
%(feet)
(min.)
(ft/sec.)
(min.)
(min.)
zoo
0.56
90.00
7.6
Tc (100)
0.40
460.00
1.50
5.1
.
.. . ..... ...
LNGST. OVERL+CHANNEL
0.45 = Runoff C 1.00 = Cf Z10 1.25 =Cf 100
SUBBASIW.T.O,C.:.4100vr)
D. Pnt.
Slope
(0/0)
C* Cf
Length
(feet)
OverLTc
(min.)
I-Vel.Chan
(fVsec.)
Tc Chan.
(min.)
Tc Total
(min.)
COMMENTS
280
0.56
280.00
11.9
Tc (100)
0.40
235.001
1.50
26
LNGST. OVERL+CHANNEL
0.45 = Runoff C 1.00 = Cf 2,10 1.25 =Cf 100
D. Pnt.
Area
(acres)
C *Of
I (2yr.)
(in/hr)
I (10yr.)
(in/hr)
I (100yr.)
(in/hr)
Basin Q
(cfs)
Comb. 0
(Cfs)--.
COMMENTS
1.33
0.45
2.15
1.2911:.,:
2 vr. runoff
0.45
3.80
2 27
23
10 yr. runoff
0.56
6.00
4.49
4,5
100 yr. runoff
0.45 C 1.00 =Cf(ZIO) 1.25 =Cf(100)
4.75 = Areatac) mis page
DATE: March 1994
HISTORIC/DEVELOPED RUNOFF COMPS. 2/10/100 YR. STORMS
FALCON RIDGE P.U.D.
FOR: SANDCREEK ASSOCIATES
BY: Stewart& Associates
GENERAL NOTES: Velocity in a Channel per FIGURE 3-2
If C x Cf > = 1 then C x Cf = I (constants listed below)
For design of the developed site runoff quantities Tc(I 00) was the basis for design IFLCOZZ,
BALQFP6ANR0.wk3
SUBBASIN.:: O.0 (100yry:
HISTORIC RUNOFF COMPUTATIONS FROM RATIONAL METHOD
0 = C x Cf x I xA
........ ...
D. Pnt.
Slope
(0/0
C Cf
Length
(feet)
Overl-Tc
(min.)
Vel.Chan
(ft1sec.)
Tc Chan.
(min.)
Tc Total
(min.L_
COMMENTS
2-00
0.25
840.00
36.6
Tc (100)
-0.20
1.00
0.00
1.50
0.0
. .. ...... ...
..... -36.6
LNGST. OVERL+CHANNEL
=Runoff C
1.00 = Cf Z10
1.25 =Cf 100
D. Pnt.
Area
(acres)
C*Cf
I (2yr.)
(in/hr)
I (10yr.)
(in/br)
I (100yr.)
(in/hr)
Basin Q
(cfs)
Comb. 0
(CIS)
COMMENTS
10.00
0.20
1.30
260
6
2 yr. runoff
0.20
2.30
4.60
4s6
10 yr. runoff
0.25
3.70
9.25
93
100 yr. runoff
0.20 = C 1.00 =Cf(zlo) 1.25 =Cf(100)
SUBBASIN::.A O.C..: (1100yrY.I.I.
D. Pnt
Slope
C Cf
Length
(feet)
Overl-Tc
(min.)
Vel.Chan
ft/sec.)
Tc Chan.
min.
Tc Total
(min.)
COMMENTS
zoo
0.25
840.00
36.61
Tc (100)
0.001
0.00
1.50
LNGST. OVERL +CHANNEL
0.20 = Runoff C 1.00 = Cf 2,10 1.25 =Cf 100
D. Pnt
Area
(acres)
C Cf
1(2yr.)
(in/hr)
I (10yr.)
1 (10 r.)
(in/hr)
Basin 0
Comb. 0
(cfs)
COMMENTS
10.00
0.20
1.30
_(in/hr)
_(cfs)
2.60
26
2 yr. ninoff
0.20
Z301
4.60
. .............
10 yr. runoff
0.25
3.70
9.25
9.31
100 yr. runoff
0.20 = C 1.00 =Cf(Z10) 1.25 =Cf 100
:X
20.00 = Area this Page
Falcon Ridge P.M.
Page 2
The site will be divided into 13 developed sub —basins that are shown on
the preliminary grading and drainage plan. Both detention ponds will be used
as sedimentation basins. Rock filters and straw bales will also be used to
filter sediment. Disturbed areas that will not be constructed on soon will
be reseeded.
The preliminary grading and drainage report and the runoff calculations
are included as a part of this report. If you have any questions regarding
this project, please call.
Sincerely,
Richard A. Rutherford, P.E. & L.S.
President
jrr
enclosures
STEWART&ASSOCIATES
Consulting Engineers and Surveyors
March 31, 1994
Mr. Basil Hamdan
Storm Water Utility
City of Fort Collins
P.O. Box 580
Fort Collins, Colorado 80522
Dear Basil:
The following is the preliminary storm drainage report for Falcon Ridge
P.U.D. The site is a proposed 21.5 acre single—family detached subdivision
located in the Southwest '—, of Section 36, Township 8 Worth, Range 69 West of
the 6th P.M. It is bounded on the north by Country Club Road, on the east
by Rim Rock Subdivision and a large metes and bounds parcel, on the south by
Spaulding Lane and on the west by a large metes and bounds parcel. The site
is in the Dry Creek Major Drainage Basin; however, the southern half of the
site is a part of the Evergreen Park Drainage Basin.
The site has an existing residence which will become Lot 61. The site
has a good cover of grass and weeds. The north half of the site drains westerly
from Ford.Lane at an approximate slope of 2.9%. The north half historically
drains into a low area on the easterly side of Colorado Highway 1 which will
become a detention pond. From the low area, the existing runoff discharges
into the southeasterly borrow ditch of Colorado Highway 1 and flows
southwesterly to the Eaton Ditch. .
The south half of. the site drains southerly to Spaulding Lane and then
westerly in Spaulding Lane to the Eaton Ditch.
It is proposed to detain the difference between the two—year historic
runoff and the 100—year developed runoff from the north half in the low area
and then continue to discharge into the borrow ditch at the historic rate.
Likewise, it is proposed to detain the 100—year developed runoff in a new
detention pond to be constructed in the Southwest corner of the site. It is
planned to continue to discharge at the historic rate into the north curb of
Spaulding• Lane.
James H. Stewart
and Associates. Inc.
103 S. Meldrum Street
P.O. Box 429
Ft. Collins, CO 80522
303/482-9331
Fax 3031482 938 2
PRELIMINARY DRAINAGE REPORT
FOR
FALCON RIDGE P.U.D.
MARCH 31, 1994
STEWART & ASSOCIATES. INC.
103 SOUTH MELDRUM STREET
FORT COLLINS, COLORADO 80521
303/482-9331