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STORM DRAINAGE REPORT
AND
EROSION CONTROL REPORT
ENGLISH RANCH THIRD FILING
PREPARED
FOR
BARTRAN AND COMPANY, INC.
PREPARED
BY
STEWART & ASSOCIATES, INC.
103 SOUTH MELDRUM STREET
FORT COLLINS, COLORADO 80521
303/482-9331
JUNE 16, 1993
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STORM DRAINAGE REPORT AND EROSION CONTROL REPORT
ENGLISH RANCH THIRD FILING
SITE LOCATION
The English Ranch Third Filing is a 10.5 acre single—family residential
site located in the Northeast a of Section 32, Township 7 North, Range 68 West
of the Sixth P.M., City of Fort Collins, County of Larimer,.State of Colorado.
The site lies within the Fox Meadows Drainage Basin. The site is located south
and east of the English Ranch Second Filing and south of the English Ranch
First Filing. The property,to the south, and east of this filing is undeveloped
and being farmed.
EXISTING CONDITIONS
The site is presently being used as an irrigated farm. The drainage is
from the south to north at a slope of about 0.75%. There is a temporary waste
water ditch along the north side of this filing which will no longer be required
and will be abandoned with this filing
Storm drainage facilities were designed and constructed with the English
Ranch First Filing. These designed plans and storm drainage report were
prepared by Stewart & Associates, Inc. in January of 1992. These facilities,
which .include detention ponds, underground storm drains, and curb inlets, were
designed per the City of Fort Collins Storm Drainage Criteria to handle storm
flows from the existing First and Second Filings and this 10.5 acre proposed
Third Filing.
The.total detention provided for the English Ranch 63—acre residential
development is 7.7 acre feet. The drainage summary for the entire 63—acre
site is shown on the English Ranch Storm Drainage Master Plan. This plan is
included with this report.
THIRD FILING DEVELOPED CONDITIONS
The storm drainage patterns for this site are as shown on the Master
Drainage Plan and are part of sub —basin areas shown as Areas 13, 14, 15, 16
and revised Sub —basin 4.
The area included in this filing drainage basin is 12.2 acres, including
1.7 acres of English Ranch Second Filing. The proposed drainage basin has
been divided into six sub —basins as shown on the Grading, Drainage and Erosion
Control Plan which is included with this report and also on Sheet No. 4 of
the English Ranch Third Filing Utility Plans. _
The Q2 amd Q10 flows at critical points are shown on the Grading, Drainage
and Erosion ControQ Plan for this Third Filing. All calculations for the
critical points are included with this report.
English Ranch Third Filing
Page 2
A small area (350 square feet total more or less) on the back of lot
191 will drain to the property south. There is•no logical or cost effective
way to charge this drainage situation, therefore we are requesting a variance
to allow this situation. Normally this back yard area will be developed in
gradens, grass and bushes. Therefore the amount of runoff to the south will
be the same as the existing condition, creating no drainaage situations because
of this development offsite. Also we are requesting a variance from the grass
slope minimum between lots 190, 191, 192, 195, 196, 197, 198, 2nd 199 of 2%.
The reason for this request is to reduce the offsite flow from our site to
the south. The minimum slope requested is for 1%. The slopes between these
lots varies from 1% to 2%. See grading plan with this report.
EROSION CONTROL
The English Ranch Third Filing is within a moderate wind and rainfall
erosion control area. Wind erosion control will be accomplished by the
installation of streets and curbs and the temporary crops. Rainfall erosion
will be controlled by placing straw bale barriers across pavement and gutters
at both the upper and lower ends of streets. The middle 12 feet of the straw
bales at the lower ends of the streets shall be left open for access to this
site.
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STEWART&kSSOCIATES 103 S. MEL9331 DRUM, FORT COLLINS, CO 80521
PH..,482-FAX 482-9382
Consulting Engineers and Surveyors
By: Date: Client: Sheet No. L of
Project: 11'eV4-
Subject:
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STEWART&ASSOCIATES 103 .S. MEL93DROR UM938FAX , FT COLLINS, CO 80521
PH..482-. 31482-2
Consulting Engineers and Surveyors
By: Date: Client:' Sheet No. z of
Project: -;7
Subject:
STEWART&&SSOCIATES 10 .S. 3 DRFM, FORT COLLINS, CO 80521
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Consulting Engineers and Surveyors
By: — ��G� Date: J`—�S� ClientiTi�i� ,���-5 Sheet No. -3 of
Project: /'?L/�<'�
Subject:
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STEWART&ASSOCIATES 113 S. MEL9331 DRUM, FORT COLLINS, CO 80521
PH. S.
FAX 482-9382
.Consulting Engineers and Surveyors
By: /Z Date: Client: Sheet No. of
Project:
Subject:
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OLLINS, CO 805212
Consulting Engineers and .Surveyors
By: Date: Client:'Sheet No. j of
Project:
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STEWART&ASSOCIATES 103 S. MEL9331 DRUM, FORT COLLINS, CO 80521
PH. 482-FAX 482-9382
Consulting Engineers and Surveyors
By: 129C X Date: �Lr/ Client."o!� Sheet No. Got-7--
Project: � — --
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GUTTER CAPACITY TABLE FOR VAIABLE STREET SLOPES AND CROSS SLOPES
2 YR EVENT WILL BE EXAMINED
FOR: ENGLISH RANCH THIRD FILING DEVELOPED BY: BART RAN HOMESOW
BY: STEWART AND ASSOCIATES
THEORETICAL CAPACITY Q = .56 (Z / n) (S) ^.5 (y) ^ 8/3
VARIABLES.AND DEFINITIONS: Q = THEORETICAL GUTTER CAPACITY (cfs)
0.42 = y (DEPTH OF FLOW AT FACE OF GUTTER, feet)
0.016 = n (MANNINGS ROUGHNESS COEFFICIENT)
S = SLOPE OF CHANNEL (feet/ feet)
Z = RECIPROCAL OF CROSS SLOPE, ( 1 / cross slope(ft / ft))
Qedu^fi^n 1oMnro oro }ram Ctnrm nroinnnn Criteria R rinnctnentinn Ctnnrinrris
DESIGN CONSTANTS
1 / CROSS SLOPE (ft / ft)
50.000 = Z = .1 /.02
1 / CROSS SLOPE (ft / ft)
40.000 = Z = 1025
1 / CROSS SLOPE (ft / ft)
33.330 = Z = 1 /.03
CHANNEL
SLOPES
REDUCTION
FACTOR
THEO.GUTTER
CAPACITY cfsCAPACITY
REDUCED
cfsCAPACITY
THEO.GUTTER
cfs
REDUCED
APACITY cfsCAPACITY
THEO.GUTTER
cfsCAPACITY
REDUCED
cfs
0:0040
0.50
10.918
5.46
8.734
4.37
7.278
3.64
0.0050
0.65
12.207
7.93
9.765
6.35
8.137
5.29
0.0060
0.80
13.372
10.70
10.697
8.56
8.914
7.13
0.0070
0.80
14.443
11.55
11.555
9.24
9.628
7.70
0.0080
0.80
15.440
12.35
12.352
9.88
10.293
8.23
0.0090
0.80
16.377
13.10
13.102
10.48
10.917
8.73
O'0100
08D
17263
13.81:
13.810
11.05
11.507
9.21
0.0110
0.80
18.105
14.48
14.484
11.591
12.069
9.66
0.0120
0.80
18.911
15.13
15.128
12.10
12.606
10.08
0.0130
0.80
19.683
15.75
15.746
12.60
13.121
10.50
0.0140
0.80
20.426
16.34
16.341
13.07
13.616
10.89
0.0150
0.80
21.143
16.91
16.914
13.53
14.094
11.27
0.01601
0.80
21.836
17.47
17.469
13.98
14.556
11.64
0.0170
0.80
22.508
18.01
18.006
14.41
15.004
12.00
0.0180
0.80
23.161
18.53
18.528
14.82
15.439
12.35
0.0190
0.80
23.795
19.04
19.036
15.23
15.862
12.69
0.0200
0.80
24.413
19.53
19.531
15.62
16.274
13.02
0.0225
0.78
25.894
20.20
20.715
16.16
17.261
13.46
0.0250
0.77
27.295
21.02
21.836
16.81
18.195
14.01
0.0275
0.76
28.627
21.76
22.902
17.41
19.083
14.50
0.0300
0.72
29.900
21.53
23.920
17.22
19.931
14.35
0.0325
0.68
31.121
21.16
24.897
16.93
20.745
14.11
0.0350
0.66
32.296
21.32
25.837
17.05
21.528
14.21
0.0375
0.64
33.429
21.39
26.744
17.12
22.284
14.26
0.0400
0.61
34.526
21.06
27.621
16.85
23.015
14.04
0.0425
0.58
35.588
20.64
28.471
16.51
23.723
13.76
0.0450
0.54
36.620
19.77
29.296
15.82
24.411
13.18
0.0475
0.57
37.624
21.45
30.099
17.16
25.080
14.30
0.0500
0.55
38.601.
21.23
30.881
16.98
25.731
14.15
0.0525
0.52
39.554
20.57
31.643
16.45
26.367
13.71
0.0550
0.49
40.485
19.84
32.388
15.87
26.987
13.22
0.0575
0.43
41.395
17.59
33.116
14.07
27.594
11.73
0.0600
0.40
42.285
16.91
33.828
13.53
28.187
11.27
0.0625
0.38
43.157
16.40
34.526
13.12
28.769
10.93
0.0650
0.36
44.012
15.84
35.210
12.68
29.338
10.56
0.0675
0.35
44.850
15.70
35.880
12.56
29.897
10.46
0.0700
0.33
45.673
15.07
36.539
12.06
30.446
10.05
0.0725
0.32
46.482
14.87
37.185
11.90
30.985
9.92
0.0750
0.29
47.276
13.71
37.821
10.97
31.514
9.14
0.0775
0.281
48.058
13.46
38.446
10.76
32.035
8.97
0.0800
0.27
48.827
13.18
39.061
1 10.55
32.548
8.79
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CONSTRUCTION SEQUENCE
PROJECT: ��I/G//S/�.�9.r/C/��STANDARD FORM C
sEQuENCE. FOR 19 ONLY COMPLETED BY: ��,� DATE: --y— / 93
Indicate by use of a bar line or'symbols when erosion. control measures will be installed.
Major modifications to an approved schedule may.require submitting.a new schedule for
approval by the City Engineer.
YEAR
MONTH
--------------------------- -i--------- --------------------------------------------------
OVERLOT GRADING
WIND EROSION CONTROL
Soil Roughing I
Perimeter Barrier j
Additional Barriers
Vegetative Methods
Soil Sealant
Other I I
RAINFALL EROSION CONTROL
STRUCTURAL:
Sediment Trap/Basin
Inlet Filters
Straw Barriers
Silt Fence Barriers
Sand Bags
Bare Soil Preparation
Contour Furrows
Terracing
Asphalt/Concrete Paving
Other
VEGETATIVE:
Permanent Seed Planting
Mulching/Sealant
Temporary Seed Planting
Sod Installation
Nettings/Mats/Blankets
Other
STRUCTURES: INSTALLED BY MAINTAINED BY
VEGETATION/MULCHING CONTRACTOR
DATE SUBMITTED
HDI/SF-C:1989
APPROVED BY CITY OF FORT COLLINS ON
RAINFALL PERFORMANCE STANDARD EVALUATION
----------------- —- =--------------------------------=----------------
! PROJECT:, �,C�GG/s,�/-,E.9if/G/!/,PO/,(/4• STANDARD FORM A
I
!COMPLETED BY: - DATE:
I----------------- ----=-------------------------------- ---------------
IDEVELOPEDIERODIBILITYI Asb I Lsb I Ssb Lb I Sb I PS
ISUBBASIN ! ZONE ! (ac) I (ft) I (%) .l(feet) I (%) I (%)
----- -- — I -------=--- I —=----- I ------- I ------- i------- I ------- -------
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1 1
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DI/SF-A:19
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EFFECTIVENESS CALCULATIONS
PROJECT: ��4�3r.� �j�,v�,� �,Pp�j,v� STANDARD FORM B
1COMPLETED BY: DATE:
� 1
Erosion Control
C-Factor
P-Factor
Method
Value
Value
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MAJOR
BASIN
PS
SUB
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4,rG I
AREA
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Comment
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CALCULATIONS
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)I /SF-B :1989
STE V VART&ASSOCIATES 10 S. ME9331 LDRUM,FAX FORT gOLLINS, CO 80521
Consulting Engineers and Surveyors
By: —�" Date: c5z5 Client: I�/ai' /��7 v'+��'� Sheet No. of
Project:
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