HomeMy WebLinkAboutDrainage Reports - 08/27/2004I
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I
HOLIDAY INN EXPRESS & SUITES
STO.RMWATER MANAGEMENT
EROSION AND SEDIMENT CONTROL REPORT
FORT COLLINS, COLORADO
LIGHTOWLER JOHNSON ASSOCIATES INC.
ARCHITECTS AND ENGINEERS
FARGO, NORTH DAKOTA
LJA PROJECT NO. 03030
STEVAN G. DEWALD
September, 2003
Revision #1
Revision #2
Revision #3
Revision #4
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TABLE OF CONTENTS
STORMWATER MANAGEMENT REPORT
NARRATIVE
SITE INFORMATION
STORAGE AREA,
RUNOFF CURVE COMPUTATION
TIME OF CONCENTRATION CALCULATIONS
TRAVEL TIME CALCULATIONS
OVERLAND FLOW CALCULATIONS
INTENSITY DURATION CURVE - 1975
TABULAR HYDROGRAPHS
STORAGE VOLUME CALCULATIONS
SYSTEM DETAILS
SYSTEM PLAN AND PROFILE
PIPE SIZING CALCULATIONS
DETENTION SUMMARY
EROSION CONTROL REPORT
INARRATIVE
SITE INFORMATION
CALCULATIONS
WQCV
PROVIDED VOLUME AND AREA
RAINFALL PERFORMANCE STANDARD EVALUATION
EFFECTIVENESS
SURETY
SAND FILTER BASIN
DESIGN PROCEDURE FORM
SYSTEM PLAN AND PROFILE
EROSION AND SEDIMENT CONTROL MEASURES
EROSION CONTROL DETAILS
ESTIMATED SITE CONSTRUCTION SCHEDULE
1
# NARRATIVE
�'.
Owner:
Lamont Companies
P.O. Box 1209
r
Aberdeen, SD 57402
Erosion Control Consultant:
Lightowler Johnson Associates, Inc.
700 Main Avenue
Fargo, ND 58103
Purpose
The following report is to describe a storm water management plan and provide
i
supporting calculations. It is also the purpose of this report to identify an Erosion control
plan during and after construction and provide supporting calculations and details.
Project Description
Lamont Companies is proposing to construct a 4-story, 89 unit Holiday Inn Express
located within Oak Ridge Business Park, Fort Collins, Colorado. The proposed structure
is a wood frame, slab on grade construction. The project site covers approximately 2.073
acres.
Existing Soils
According to the Geo-technical Report generated by Kumar and Associates, Inc, native
soils consist mostly of sandy lean clay underlain with poorly graded clayey sand and sand
with clay and gravel.
Site Conditions
The site is mostly flat with grass and weeds. Currently all stormwater runoff is diverted
onto Wheaton Drive, Oakridge Drive, the ditch along Harmony Road or infiltrates into
the ground. Full detention for the 100-year storm event is to be provided with this
development.
Adjacent Areas
Surrounding development consists of office and commercial development. The site is
bounded by Oakridge Drive to the South, Harmony Road to the North and Wheaton
Drive to the West. The East property line is adjacent to an existing International House
of Pancakes restaurant.
Storm Water Runoff Analysis
The 100-year storm, using the City of Fort Collins computer spreadsheet was used to
determine detention volume requirements to be 0.395 acre-feet. The 100 year storm was
used to design all storm water apparatus The proposed storm water management system
will consist of a series of PVC yard drains, downspout leaders, and PVC pipes that divert
storm water to a Sand Filter Basin. Extended detention will occur in the parking lot.
Storm water will also run overland to the Sand Filter Basin. The sand filter basin is to be
1
underlain with perforated drain -tile and connect directly to the outlet structure. The
outlet structure shall have a 4.4" orifice to restrict the outflow rate to 1.2 CFS. A 15-inch
(min.) RCP will connect the outlet structure to an existing city inlet located on Wheaton
Drive. Overflow will take place through the inlet grate on the control structure.
Emergency overflow will take place at the site entrances. The maximum designed
ponding depth is 11.4 inches. A total of 0.395 acre-ft of storage is required for this site.
The provided storage is 0.435 acre-ft.
�.
The existing 24-inch RCP located under Wheaton Drive (Conveyence element 34) has
capacity for approximately 16 CFS. It currently transports 2.1 CFS from Basin 340 and
up to 12.4 CFS from Basin 160 (street flow) for a total of 14.5 CFS. Capacity of the
existing RCP would not be exceeded by introducing an additional 1.2 CFS.
Sediment Control
•
All storm water has been directed to a Sand Filter Basin and will infiltrate into an under
drain system prior to discharge. The SFB was designed according to the UDFCD
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Drainage Criteria Manual (Volume 3).
Temporary Stabilization Measures
During construction, a vehicle tracking control pad will be used at the construction
entrance on Oakridge Drive. Silt fence will be installed around the perimeter of the
construction site prior to grading activities. The sand filter basin will be installed early
during construction will provide sediment control during and after construction. Silt
fence with rock filter outlets will be installed around the Sand filter basin and remain in
place until pavement is installed. Hay mulch will be placed on all exposed areas.
Temporary be
crops will planted in areas where work will not resume within 30 days.
Permanent Stabilization Measures
Permanent landscaping will include a mixed sod, plantings, trees and shrubs. The sand
filter basin will provide sediment control after construction is complete. The outlet
structure and under -drain system shall be installed early in the project to ensure water
quality is maintained.
Construction Materials and Equipment
The contractor shall store all construction materials and equipment and shall provide
maintenance and fueling of equipment in confined areas on site from which runoff will be
contained and filtered.
Maintenance
The erosion control measures will be inspected weekly during construction. Silt fencing
will be checked for undermining and bypass and repaired or expanded as needed.
Mulching of bare soils will be checked regularly and areas where it was lost or damaged
will be re -mulched within seven working days when needed. Temporary vegetation shall
be maintained and replaced if required.
11
Calculations
Calculations for the sand filter basin are provided herein. Details for the erosion control
measures can be found on Sheets C-7, C-8, C-9 & C-10. Details are also provided in this
report. The calculated volume for WQCv was determined to be 0.043 acre-feet, 0.050
acre-feet is provided. The required filter surface area (Pond Bottom Area) was calculated
to be 624 SF, 632 SF has been provided. The maximum depth of the Water quality pond
is 1.375 feet. The maximum depth of the detention system is 2.325 feet.
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10 Year
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10-Year---
Composite 'C-2.0731
Area
Release Rate
_
0.75
�2.073
1.2
------
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_ _M(_odified
,M. FATERID.
-
-
----
JUDIS
�- -
-
Modified
-
C. LI
_-
T 5/951
Apr-98 N6v-98
DETENTION POND
REVISED INTENSITIES--
SIZING T
TIME I ETNI ETN NSITY! Q 10 Runoff
curn yea
-�
j _Release
Cum total
Required Required
Detention_ ! Detention
TIME
-
- (mins)
_Volume
(secs) /ni hr) (cfs) (ft^3)
(ft^3)
_0_--
.01 1-- 0 0.00'
30.01 4.870 7.57 2271�3600__911.5
.0 [ 0.0000945
0.04
10
-0
001 3.70 5.- 526I
720.0
2806.20.064
20
00� 3.1904.96 44
I
1200 2.7401
10-80- .0
70.07715
3831
- -
--- 255
- 4_26 -5112
-11500T_ 2.44� 3.79-
, 5690+
-
1440.01
_ 1800.0(
_ 3672.0 0.0843
3890.4� 0.0893
F---f-----
30
- - 1-
35
I-
1800 2.210 3... 6185
--- + -----
2100 2.000 3.11 6530
2160.0
2520.0
4024.81 0.0924
----- --
40
- -- -- --- ---�
2400 1.830 2.85
-- -- 1
4010.0 0.0921
- -
6828
2880.0,
3948.5 0.0906
45
50!
2700 - 1.690 - 2.63 1 -7094
3000 1.580� 2.461 73701
3240.01-
3854.3 0.0885
_
55
_-__- -
3300 1.480 7593
2.30
3600.0 t
3769.51 0_0865
36_33.4I 0_0834
601
_ _
3600 1.400 2.18 7836
_3960.0
4320.01
-
3515.91 00807
_ 651--390_0�
707
1.320 2.05 j 8004T
_ 1._25_01
4200
46800.
- 332391 0.0763
- - - -
i _ 1.9_4 i 8162
-
5040.0�
3122.4 0.0717
--- 75I
4500; 1.1903� -1.85 8326II
-� - - - t----
5400.01
-�-
2925.71 0.0672
--
80r
4800T 1.140; 1.77; 85081
5760.0
2747.6! 0.0631
85
-------91 86 3
5100 1.090! 1.69j _ 86431
---
6120.0!_
- -- -- --
2522.91 0.0579
90
- -- ---
5400 1.050� 1.63T 8815�
---1.57 -
_6480.0'
-- I--
23354 0.0536
-- -
95
10016000r_
5700�-- 1.0108951 !!
----- 1
0.970j- 1_51T- 9049;--7200.O1
6840.01
_211_0.7 0.0485
1-------
1848.6' 0.0424
---
- 105;
110 L
6300 0.940j _ _1.46! _ 9207I
6600 0.9101 1.411 93381
7560
7920.01
1647.21 0.0378
141_7.8 0.0325
1151
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8280.0 j
1160.41
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7200! 0.8601 1.34fi- 9627!
8640.0!
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Page 1
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2-year
Composite 'C'
0.75
Area
2.073
Modified
Modified
Release Rate
1.2
M. FATER
D. JUDISF
C. Li
5/95
Apr-98
Nov-98
DETENTION POND SIZING
REVISED INTENSITIES
TIME
TIME
INTENSI
02
Runoff
Release
Required
Required
cum
2 year
Volume
Cum total
Detention
Detention
(mins)
(secs)
(in/hr)
(cfs)
(ft^3)
(ft^3)
(ft^3)
(ac-ft)
0
0
0
0.00
0
0.01
0.01
0.0000
5
300
2.850
4.43
1329.311
360.0
969.31
0.0223
10
600
2.210
3.44
2061.599
720.0
1341.6
0.0308
15
900
1.870
2.91
2616.644
1080.0
1536.6
0.0353
20
1200
1.610
2.50
3003.777
1440.0
1563.8
0.0359
25
1500
1.430
2.22
3334.939
1800.0
1534.9
0.0352
30
1800
1.300
2.02
3638.115
2160.01
1478.1
0.0339
35
2100
1.170
1.82
3820.021
2520.0
1300.0
0.0298
40
2400
1.070
1.66
3992.598
2880.0
1112.61
0.0255
45
2700
0.990
1.54
4155.847
3240.0
915.81
0.0210
50
3000
0.920
1.43
4291.11
3600.0
691.11
0.0159
55
3300
0.870
1.35
4463.687
3960.0
503.71
0.0116
60
3600
0.820
1.27
4589.622
4320.01
269.61
0.0062
65
3900
0.770
1.20
4668.914
4680.0
-11.1
-0.0003
70
4200
0.730
1.13
4766.864
5040.0
-273.1
-0.0063
75
4500
0.6901
1.07
4827.499
5400.0
-572.5
-0.0131
80
4800
0.6601
1.03
4925.4481
5760.0
-834.6
-0.0192
85
5100
0.6301
0.98
4995.4121
6120.0
-1124.6
-0.0258
90
5400
0.6101
0.95
5121.3471
6480.0
-1358.7
-0.0312
95
5700
0.580
0.901
5140.0041
6840.0
-1700.0
-0.0390
100
6000
0.560
0.871
5223.96
7200.0
-1976.0
-0.0454
105
6300
0.540
0.841
5289.2E
7560.0
-2270.7
-0.0521
110
6600
0.520
0.81
5335.902
7920.0
-2584.1
-0.0593
115
69001
0.510
0.79
5471.165
8280.0
-2808.8
-0.0645
120
72001
0.490
0.7E
5485.158
8640.0
-3154.8
-0.0724
100 Year
i
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
This is to convert % imp. to a C value
- - -- --
I---- ---
- y --
-_ (must insert % imp_and C pervious).
-. -- -------
Required detention
L -- - -- - --!---
19751NTENSITIES I
i ft'
--
acre-ft.
0.75--
---�---
13997.4 1
0.3213
'C' • 1.25 0.9375 -�- -- r---
Area _ _
2073.acres _-, _--�
__ ---� Modified I
Modified
Release Rate
1.2 _ _
1M. FATE RID. JUDIS
_
C. I -I_
5/95' Nov-97!
Nov-98
DETENTION POND SIZING I
------
TIME - ,-
-------
--------0
TIME I_NTEN_SITYIQ100
-
1----- --- a.--equ ---
1 Ru_noff ;Release Required � R_equired
_ I
cum j 100 year '
I Volume I Cum total i Detentio_nDetention
(mins) -
(secs) (in/hr) (cfs)
(ft^3) (ft"3)� (ft"3)
(ac-ft)
0 0 0.001
0� 0.0
-- --0
-- - -
..
0
---
0000
000
5,
---
300 8.500 16.52,
-- -
..._.L--0
---0
4955.77L, 360.01 4595.8E
7- --
-
0.1055
10
6001- 7 100 13.80�8279.04
,
720 0 7559.01
0.1735
15
900i- 6 000 - 11.66'
10494.56� 1080 0i 9414.6
_-
0.2161
_
20
--- -- -1 -
25!
1200 5.200 10.11
- - - 1----- ---
15001 4.600 8.94
_
12127.051 1440.0 10687 1�-
13409_72;- 8800:0
0.2453
---- -- +----
- - f- - -- -_
_
11609.7
- -
0.2665
301
1800�-- 4_200j 8.161
--------0.287
14692_39L--2160_0, 12532.4i
0.2877
-- 35�
21001 3 800i 7.39�
- -
15508.631 2520.01
0.2982
40
_..._.-------
240013.500 i 6.80;
-----
-12988.6�
16324.88 2880 0 13444 9'
i-
0 3087
45,
501
27001 3.250� 6.32-
-_.s.-.___-_.._
3000 3.000 5.83117490_941
--
17053.66: 3240.0; 13813.71
__._-_-_-___...._-.._..�..-.3813.-_._-...
3600.0! 13890.9i
_..
0.3171
0_3189
- -._... ----5' ----
----'
--- - --
55;
3300 2.800 5.44
--
17957.36t 3960.0! 13997.41
0.3213
60;
-----..-._...
3600' 2.600! 5.05!18190.58;
_- - ..----- 1-- _.----
4320.Oi 13870.6)
-_ --- - -
0.3184
4.ful 18569 551 4680 0' 13889.5; 0.3189
42001 -- 1 - --
_75; _ 4500i 2.150I I _4.18I 4.471 18773.611 50400j 13733.E! 03153
_ 18802.7615400.Oj 13402.81 0.3077
-r-- -------..._.... -
-- 851 54000 1.950,---- 3.7t19327.49j_-6120-13207.5,- 0.3068
80; 4800 2.050 1 3.98 1 19123 4_3 5760.0 13363.4
90i
__ � - _ 0.3032
--
1.855� 3.60, 19414.94� 6480.0 12934.9 0.2969
_ 5700 j1.750' 3=I--
40 ! 19385.791 6840.0 12545.8 _ _ 0.28_80
--- -
100 6000 1.7001 ---3.30 82 i 193.06 7200.01 12623.1 ! 62898
105; 63001 1.650! 3.21120202.031 7560.0j 12642.01 0.2902
-110 6600, 1.550; 3.011 19881.37! 7920 0 11961.4, 0.2746
- 115}69001.5001 _ 2.9_2! 20114.581 8280.0� 11834.6! _0.2717
120!_ 72001 1.4501 2_821 20289.491i 8640.0! 11649.5[-0.2674
125' 75001 1.380! 2.68 i 20114.581 9000.0! 11114.6 0.2552
130 7800i 1.300 2.53;' 1970E_46 9360.0 10346.5 _ 0.2_375
1351 8100 1.280' 2.49 20149.561 9720� 10429 66 0.2394
-1-- 4-0 -�--
140; 8400 1.250i 2.431 20406.091 10080.01 10326.1� 0.2371
T-- - -- - -- --
145T 8700 1.210� 2.35; 20458.57� 10440.01 10018.6i 0.2300
{-- -
150-i- 9000 i ----- -- -155r1 ---- -- 9--- +I -- --1.18-0 -2-.29r; -2-0--6- 9-.-3- -10-8-01 �----9-8--3-9--.-+! --- --0-..2-259
02251300, 1.160 220965; -11160.01 9805.8
1661- - 9600'20895.84�_11520.Oi- 9375.81 _0.2152
1651 9900 1.110E 2.1E 21356.43 11 1880.01 _ -_! _ _ _ _ i-- 9476.4 _0.2175
-170 10200; 1.100- 2.14E 21805.37; 12240.0_t_ 9565.4' 0.219E
175, 10500!--1.080! 2.10. 22038.581F 12600.0, 9438.6! 0.2167
Page 1
10 Year
10 year POST DEVELOPED
1975 INTENSITIES
Composite 'C'
_ 0.75
-
�
�-
Area 7
_
2.073 �------
_
-� _
�---- - ---
Modified Modified
-+- �-
Release Rate
_ -
1.2;
__
,M. FATER�D. JUDIS_H_C. LI
--
I 5/_9_5 j _Apr-98 Nov-98
DETENTION POND SIZING--i-
�,,Requirecl
-TIME
TIME_iIN_TENSITYi Q 10
Runoff�Release Required
10 year
--- ----- -- - }--- --- --
_1
---
Volume Cum total Detention a entn t io
i- -- -� ---
{--(ft^3)'
---(mins) -- (secs)
(in/hr)-
(cfs) I-
(ft^3) (ft"3)- i (ac-ft)
-
5!
3001
5.650 8781
2635 360.Of 22750.0522
15
900
7.00;
-0--.0---0-0-
4-98 0.07
3.700t
5.75{
5.051
100.0.0
771000]__477.8I_
80.01 4097.3 0.0941
-
-_-_-..0
6064 4623�0.106
---_
_._-_
1500
2.900
2.6001
4.51
4.041
0.1139980218001
7276
60A!---
5116.2 0.1175
r.._
__ __-
7673 2520_0 5152.7--_ 0.1183
40
24001
2.200
3.42
- -
8209 2880.0) 5329.1 0.1223
45'
2700I
2.0001 3.11 f
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Page 1
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2-year
POST DEVELOPED
1975 INTENSITIES
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TIME
TIME
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'i
STORAGE VOLUME FOR DETENTION BASINS Version 2.00
Project : Oakridge Business Park 36th Filing, Holiday Inn Express User: SGD
County : Larimer State: CO Checked: Date: 6-04
Subtitle:
Drainage Area: 2.073 Acres Rainfall Frequency: 100 years
Rainfall -Type: II
24-Hour Rainfall: 7.74 inches Runoff Curve Number: 75
Peak Inflow: 10.306 cfs
Peak Outflow:. 1.2 cfs
Runoff Volume: 4.8 inches
Detention Basin Storage Volume: 2.58 inches or 0.4 acre feet
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HOLIDAY INN EXPRESS & SUITES
EROSION CONTROL REPORT
FORT COLLINS, COLORADO
LIGHTOWLER J.OHNSON ASSOCIATES INC.
ARCHITECTS AND ENGINEERS
FARGO, NORTH DAKOTA
LJA PROJECT NO.03030
STEVAN G. DEI
REGISTRATION
NAL�G\a cC
September, 2003
Revision #1
Revision #2
Revision #3
Revision #4
TABLE OF CONTENTS
NARRATIVE
SITE INFORMATION
CALCULATIONS
WQCV
'PROVIDED
j
VOLUME AND AREA
RAINFALL PERFORMANCE STANDARD EVALUATION
EFFECTIVENESS
SURETY
SAND FILTER BASIN
DESIGN PROCEDURE FORM
SYSTEM PLAN AND PROFILE
EROSION AND SEDIMENT CONTROL MEASURES
EROSION CONTROL DETAILS
ESTIMATED SITE CONSTRUCTION SCHEDULE
1
I
1
NARRATIVE
Owner:
Lamont Companies
P.O. Box 1209
'
Aberdeen, SD 57402
Erosion Control Consultant:
Lightowler Johnson Associates, Inc.
700 Main Avenue
Fargo, ND 58103
Purpose
The following report is to describe a storm water management plan and provide
supporting calculations. It is also the purpose of this report to identify an Erosion control
plan during and after construction and provide supporting calculations and details.
Project Description
Lamont Companies is proposing to construct a 4-story, 89 unit Holiday Inn Express
located within Oak Ridge Business Park, Fort Collins, Colorado. The proposed structure
is a wood frame, slab on grade construction. The project site covers approximately 2.073
acres.
1
Existing Soils
According to the Geo-technical Report generated by Kumar and Associates, Inc, native
soils consist mostly of sandy lean clay underlain with poorly graded clayey sand and sand
with clay and gravel.
1
I
Site Conditions
The site is mostly flat with grass and weeds. Currently all stormwater runoff is diverted
onto Wheaton Drive, Oakridge Drive, the ditch along Harmony Road or infiltrates into
the ground. Full detention for the 100-year storm event is to be provided with this
development.
Adjacent Areas
Surrounding development consists of office and commercial development. The site is
bounded by Oakridge Drive to the South, Harmony Road to the North and Wheaton
Drive to the West. The East property line is adjacent to an existing International House
of Pancakes restaurant.
Storm Water Runoff Analysis
The 100-year storm, using the City of Fort Collins computer spreadsheet was used to
determine detention volume requirements to be 0.395 acre-feet. The 100 year storm was
used to design all stone water apparatus The proposed storm water management system
will consist of a series of PVC yard drains, downspout leaders, and PVC pipes that divert
storm water to a Sand Filter Basin. Extended detention will occur in the parking lot.
Storm water will also run overland to the Sand Filter Basin. The sand filter basin is to be
7
underlain with perforated drain -tile and connect directly to the outlet structure. The
' outlet structure shall have a 4.4" orifice to restrict the outflow rate to 1.2 CFS. A 15-inch
(min.) RCP will connect the outlet structure to an existing city inlet located on Wheaton
Drive. Overflow will take place through the inlet grate on the control structure.
Emergency overflow will take place at the site entrances. The maximum designed
ponding depth is 11.4 inches. A total of 0.395 acre-ft of storage is required for this site.
The provided storage is 0.435 acre-ft.
The existing 24-inch RCP located under Wheaton Drive (Conveyence element 34) has
capacity for approximately 16 CFS. It currently transports 2.1 CFS from Basin 340 and
up to 12.4 CFS from Basin 160 (street flow) for a total of 14.5 CFS. Capacity of the
existing RCP would not be exceeded by introducing an additional 1.2 CFS.
Sediment Control
All storm water has been directed to a Sand Filter Basin and will infiltrate into an under
drain system prior to discharge. The SFB was designed according to the UDFCD
Drainage Criteria Manual (Volume 3).
Temporary Stabilization Measures
During construction, a vehicle tracking control pad will be used at the construction
entrance on Oakridge Drive. Silt fence will be installed around the perimeter of the
construction site prior to grading activities. The sand filter basin will be installed early
during construction will provide sediment control during and after construction. Silt
fence with rock filter outlets will be installed around the Sand filter basin and remain in
place until pavement is installed. Hay mulch will be placed on all exposed areas.
Temporary crops will be planted in areas where work will not resume within 30 days.
Permanent Stabilization Measures
Permanent landscaping will include a mixed sod, plantings, trees and shrubs. The sand
filter basin will provide sediment control after construction is complete. The outlet
' structure and under -drain system shall be installed early in the project to ensure water
quality is maintained.
' Construction Materials and Equipment
The contractor shall store all construction materials and equipment and shall provide
maintenance and fueling of equipment in confined areas on site from which runoff will be
contained and filtered.
Maintenance
The erosion control measures will be inspected weekly during construction. Silt fencing
will be checked for undermining and bypass and repaired or expanded as needed.
Mulching of bare soils will be checked regularly and areas where it was lost or damaged
will be re -mulched within seven working days when needed. Temporary vegetation shall
be maintained and replaced if required.
I
Calculations
Calculations for the sand filter basin are provided herein. Details for the erosion control
measures can be found on Sheets C-7, C-8, C-9 & C-10. Details are also provided in this
report. The calculated volume for WQCv was determined to be 0.043 acre-feet, 0.050
acre-feet is provided. The required filter surface area (Pond Bottom Area) was calculated
to be 624 SF, 632 SF has been provided. The maximum depth of the Water quality pond
is 1.375 feet. The maximum depth of the detention system is 2.325 feet.
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DRAINAGE CRITERIA MANUAL (V. 3)
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S-52
STRUCTURAL BEST MANAGEMENT PRACTICES
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.7 S0.8 0.9 1
Total Imperviousness Ratio (!-1, 1100)
L.. Or75
FIGURE SFB-2
Water Quality Capture Volume (WQCV), 80'" Percentile Runoff Event
Rev. 6-2002
Urban Drainage and Flood Control District
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11
LIGHTOWLER JOHNSON ASSOCIATES
INCORPORATED
ARCHITECTS ENGINEERS
3o f to y9�6.3�s `c s � s` A faik B T�.l Aw•7q T64.1 o u,l
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FFICVE BOX 2464
NORTH DAKOTA 58108.2464
(701) 293-1350 (ND)
1218) 233.3512 (MN)
FAX 1701) 293.1353
EMAIL: lia@lightowlerichnson.com
VVEBSITE: www.liahtowl.ri..1...—
___
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RAINFALL PERFORMANCE STANDARD EVALUATION
MARCH 1991 8-14
DESIGN CRITERIA
I.
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TABLE 5.1,
EFFECTIVENESS CALCULATIONS
PROJECT:
OuK-( fo Ns_ b, ,
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Yk .36 F,.; ,:�-Y STANDARD FORM B
r�
COMPLETED BY:
:5(>k-13,c-' .455c,c..4 DATE:
Erosion Control
C-Factor P-Factor
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Method
Value Value Comment
$pra So.I
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1,0 0,5'
Ro: 511"-It
0- 0 I 1.0
5:141-�.re
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MAJOR PS SUB
AREA
BASIN ($) BASIN
(Ac)
CALCULATIONS
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8-15 DESIGN CRITERIA
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MAIN AVENUE (701) 2?3-135C iNIM
ST OFFICE BOX 2,164 (218I 2.3-3512 im:J1
WIGO, NORTH DAKOTA 531 i'F.-21c
FAX (7671 -193-7353
EMAIL: !j; com
VVEBSITG: v ^n^n.ii h!p alerioMscn.co n
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Designer.
Company:
Date:
Project:
Location:
1. Basin Storage Volume
lam%
t+= _.
A) TribularyArea's Imperviousness Ratio (i = I,/ 100)
i = "" O '
B) Contributing Watershed Area (Area)
Area = • � acres
C) Water Quality Capture Volume (WOCV)
(WOCV ' 1.0 ' (0.91 ' t� • 1.19 ' 1 + 0.78
WOCV = Q�'. watershed inches
D) Design Volume: Vol = (WOCV / 12)' Area
Vol = `a;.+OYA acre-feet
2. Minimum Filter Surface Area: (Vol/ 3) - 43.560
A, ip 612q square feet
Fitter Surface Elevation
Lu=
`)l �b.J/77 3 feet
r
Average Side Slope of the Filter Basin (4:1 or flatter)
2 =�
I3. Estimate of Basin Depth (D), based on fitter area # I D = 1._ // . feet
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4. Oullet Works
A) Sand (AS TM C-33) Layer Thickness (I a' min.)
po
�Q inches
B) Woven Monofilament Fabric Between Sand 8 Gravel-
_Carthage Mill, Carthage 15%
Carthage MII, Carthage 15% (or equal)
Other:
C) Gravel (AASMTO No. 67; CDOT Section 703) Layer
Thidmes (8' min.)
p
O inches
D) Overflow Elevation At Top of Design Volume
�p
1 h� beet
(Filter Surface Elev. + Estimate of Basin De lh D)
5. Draining of porous pavement (Check A. or S. or C,answer D)
Based
��,? Infiltration to Subgrade with Permeable
on answers to SA through 5D, check the appropriate method
Membrane: 5(C) checked and 5(D) = no
A) Check box if subgrade is heavy or expansive day
B) Check box tl subgrade is silly or clayey sends
'" /� Underdrain with Impermeable
Membrane: 5(A) checked
C) Check
or 5(D) =yes
box 0 subgrade s well -draining soils
D) Does tributary catchment contain land uses that may have
...............
Underdrain with Permeable Membrane:
5(B) checked and 5(D) -no
petroleum products, greases, or other chemicals
present, such as gas station, yes no
Other:
hardware store, restaurant, etc.?
6. Describe Provisions for Maintenance
drier w h L , ;- or r0 '
USDCM VOL 3 BMP Design Fonns v2.O3 (2DO20925).xls, SFB
2002-06 revision
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WOVEN MONOFILIMENT FABRIC
SEE SPECS. IN PROFILE VIEW
1 3n
' 8„ MIN.
GRAVEL LAYER
� til,�zV�, .y
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171
FILTER BED SECTION
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-PERF. HDPE PIPE
AS SPECIFIED
MIL POLY
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77.75 FL
INLET GRATE i
76.375 SAND SURFACE-,,,,,, IM76.65 I
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5 15 INV � 75 20 NV..-
74.875 GRAVEL SURFACE` _
FILTER FABRIC 12" PVC ® 1.2%
'" -' �' � ' -' I' � � =1' �--'
I30 MIL POLY --I -I �74.90 BOTTOM
4" PERFORATED DRAIN PIPE
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12" PVC
#4 BARS 6" O.C.E.W
GRATE
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FABRICATED G; VANIZ D„ BA S
1-1/2 OPENINGS
REMOVABLE
12" PVC --z--�
CONCRETE OUTLET BOX
C-10 NO SCALE
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A. Soil Erosion and Sedimentation Control Measures, Permanent Stabilization, and
Maintenance
1. The erosion, sediment, stabilization and runoff control will be accomplished by
the use of the following during and after construction:
Establishment of temporary and permanent vegetative cover
Non-structural measures
Structural measures
B. Establishment of Vegetative Cover
Slopes shall not be left unattended or exposed for excessive periods of
time such as the inactive winter season.
2. All existing gravel areas not utilized for driveway access are to be loamed
and seeded.
' 3. The topsoil shall have a sandy loam texture relatively free of subsoil
material, stones, roots, lumps of soil, tree limbs, trash or construction debris and
shall conform with standards and specifications of Urban Drainage and Flood
Control District (Denver, Colorado) the City of Fort Collins and Larimer County.
4. The seeding design mix shall be comprised of the following:
TYPE
LBS/AC
INTERMEDIATE WHEATGRASS
2.5
WESTERN WHEATGRASS
4.0
BLUE GRAMA
0.75
SMOOTH BROME
3.25
GREEN NEEDLEGRASS
2.4
5. Early spring or late summer seeding is recommended. Lime and
fertilization as required by soil testing to compliment or upgrade existing
conditions. The seed mix shall be inoculated within 24 hours and before mixing
and planting.
1 6. Temporary treatment shall consist of North American Green erosion
control blankets such as S 150 or approved equal. They shall be incorporated into
the work as warranted or as ordered by the engineer. Hay or straw applications
' shall be in the amount of 2 tons/acre.
7. Silt fence and other temporary protection shall remain in place until an
acceptable stand of grass or approved ground cover is established.
8. All fill shall be thoroughly compacted upon placement in strict
conformance with Colorado Standard specifications.
I
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9. Stockpiles of topsoil shall not be located near waterways. They shall have
side slopes no greater than 2:1 and shall be temporarily seeded and/or stabilized.
10. The construction superintendent shall have overall responsibility for plan
implementation and for seeing that the appropriate workers are aware of the
provisions of the plan. The contractor must repair and/or reseed any areas that do
not develop within the period of one year and shall do so at no additional expense.
�!
11. All areas disturbed by construction shall be stabilized with paving or
permanent seeding immediately following finish grading. Permanently seeded
areas shall be protected during establishment with mulch. All seeded areas will
be checked regularly to see that a good stand is maintained. All areas shall be
fertilized and reseeded as necessary.-- '"
'
12. Reference the "Drainage Criteria Manual (Volume 3)" prepared by the
Urban Drainage and Flood Control District.
13. Temporary hay mulch to be tacked in place with nylon mesh netting.
14. Maximum graded slope within the Site is to be 3:1, unless specified otherwise.
C. Non -Structural Measures
1. Construction traffic shall be limited to access roads, drainage easements,
and areas to be graded.
2. A stone stabilization pad is located at the site entrance along Oakridge
Drive to reduce the tracking or flowing of sediment onto the public right-of-way.
3. The contractor shall maintain the entrance. The maintenance shall include
top dressing with additional stone or additional length as conditions demand or as
directed by the engineer. All sediments spilled, dropped, washed, or tracked onto
the public right-of-way must be removed immediately by the contractor.
4. Topsoil shall be stripped from areas to be graded and stockpiled for later
ruse.
Stockpile location shall be subject to approval by the project engineer. A
sediment barrier should surround all topsoil stockpiles.
'
S. Silt fence shall be installed downstream outside the limits of any proposed
construction as shown on the site plans and prior to the commencement of the
rproposed
alteration.
6. Rock filter outlets shall be installed with silt fence around Sand Filter
Basin as indicated on Erosion and Sediment control plan and as required.
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7. The contractor shall maintain the silt fence. Inspection shall be made after
each storm event and repaired or replaced as warranted. The contractor shall
clean the accumulated sediment if half of the original height of the fence becomes
filled in with sediment.
1; 8. The contractor shall check the silt fence weekly for undermining or
deterioration.
9. The construction superintendent shall have overall responsibility for plan
implementation of non-structural measures and for seeing that appropriate
workers are aware of the provisions of the plan.
107 Reference the "Drainage Criteria Manual (Volume 3)" prepared by the
Urban Drainage and Flood Control District.
D. Structural Measures
1. A parking lot pond detention system is used to control runoff. Pipe flow
discharge from yard drains and building downspouts into the sand filter basin
shall occur in an outlet box structure. The outlet box structure is designed to
minimize flow velocity.
2. Overland discharge into the sand filter basin shall occur at curb openings
as indicated on the site plan. Rip -rap aprons shall be placed on sand filter basin
side slopes at curb opening locations. Runoff water quality is improved utilizing
6" to 12" stone rip -rap to lower discharge velocity. Rip -rap shall be underlain with
' geofabric.
3. A permanent cover shall be established in accordance with the vegetative
cover provisions. The seeding shall extend to at least the design top width of the
BMP's and include any other areas disturbed by construction activities. Activities
shall be confined to within the limit of work as shown on the plans.
4. Vigorous vegetation shall be maintained on sand filter basin side slopes
not covered with rip -rap by applying lime and fertilizer. Bare or eroded areas
shall be immediately repaired and reseeded by the contractor. Sod shall not be
placed on sand filter basin surface.
5. The contractor is responsible for maintenance and inspection of the
detention area and storm water appurtenances up to a year after completion of
' construction. The Owner is responsible thereafter.
6. The contractor shall be responsible for maintaining the all•BMP's during
construction and the detention area up to the acceptance by the Owner. The
Owner shall be responsible thereafter for the detention area, and drainage system.
The Owner shall inspect the detention area semi-annually and after major storms.
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7.
Rip -rap pads shall be inspected annually and after major storms. If repairs
are needed, they shall be accomplished immediately.
8.
The construction superintendent shall have the overall responsibility for
structural measure implementation and for seeing that appropriate workers are
aware of the provisions of the plan.
9.
Reference the 'Drainage Criteria Manual (Volume 3)" prepared by the
'
Urban Drainage and Flood Control District.
- E.
Maintenance: Short Term/Long Term
'
1.
All disturbed slopes either newly created or currently exposed shall be
seeded, protected, and maintained by the contractor following final grading and
construction. The contractor shall check regularly all seeded areas to see that a
good stand is maintained.
2.
The contractor must repair or reseed any areas that do not develop within
the period of one year and shall do so
at no additional expense.
3.
The contractor shall maintain all topsoil stockpiles and sediment barriers
throughout construction. Extreme be
care shall taken to ensure that sediments do
not spill over the sediment barrier.
4.
The contractor shall check silt fence on a weekly basis and after each
storm for undermining or deterioration. The contractor shall clean the
accumulated sediment if half of the original height of the fence becomes filled in
with sediments.
5.
The contractor shall maintain the stone stabilization pad at the site
entrance. The maintenance shall include top dressing with additional stone or
additional length as conditions demand or as directed by the engineer. All
'
sediments spilled, dropped, washed, or tracked on the public right-of-way must be
removed immediately by the contractor.
' 6. The contractor is responsible for maintenance and inspection of the
detention areas during and up to a year after completion of construction.
Maintenance shall include removing sediments and trapped oil from the sediment
basins and maintaining the pipe outfall location on the property as needed.
7. The contractor shall maintain the drainage system throughout
construction. The accumulated sediments in the detention areas shall be removed
and drainage pipes flushed by the contractor at the end of construction.
I�
I
8. The Owner is responsible for the long-term maintenance of the above
ground detention area and sand filter basin. The drainage system shall be checked
semi-annually. Maintenance shall include removing sediments from the detention
area and maintaining the pipe outfall location as needed. Sediment shall be
removed from the sand filter basin when the sediment level reaches the rim of the
outlet box structure. Sediment in the control structure and the outlet box structure
shall be removed when sediment level reaches the lowest pipe inverts. Bi-annual
sweeping of the parking lot is recommended to coincide with fall cleanup from
leaves and spring cleanup from winter sanding activities.
' 9. The construction superintendent shall have overall responsibility for the
maintenance program during the construction phase. The superintendent shall see
that the appropriate workers are aware of the provisions of the plan.
10. After the first year and acceptance by the Owner, the Owner shall have
overall responsibility for implementing the maintenance program.
I
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7
DRAINAGE CRITERIA MANUAL (V.3)
MAINTENANCE RECOMMENDATIONS
7.0 SAND FILTER EXTENDED DETENTION BASIN (SFB)
11
1 --
I
TABLE SFB-1
Sand
Filter Detention Basin Maintenance Considerations
Required Action
Maintenance Objectives
Frequency
Debris and litter removal
Remove debris and litter from
Routine — depending on aesthetic
detention area to minimize dogging
requirements
of the sand media.
' Landscaping removal and
replacement
If the sand filter is covered with rock
mulch, bluegrass, or other
Every 2 to 5 years
landscaping covers, the cover must
be removed to allow access to the
sand media. Replace landscaping
cover after maintenance of sand
'
media is complete.
Scarify Filter Surface
Scarify top 3 to 5 inches by raking
Once per year or when needed to
the fillers surface.
promote drainage.
Sand filter removal
Remove the top 3 inches of sand
If no construction activities take
from the sand filter. After a third
place in the tributary watershed,
'
removal, backfill with 9 inches of new
sand to return the sand depth to
every 2 to 5 years depending on
observed drain times, namely when it
18 inches. Minimum sand depth is
takes more than 24 hours to empty
12 inches.
3-foot deep pool. Otherwise more
'
often. Expect to dean out forebay
every 1 to 5 years.
Inspections
Inspect detention area to determine if
Routine — bi-annual inspection of
the sand media is allowing
hydraulic performance, one after a
'
acceptable infiltration.
significant rainfall.
' MR-8 9-1-99
Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL (V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES
VEHICLE TRACIUNG CONTROL
Definition
A stone stabilized pad located at points of vehicular ingress and egress on a construction
site.
Pumes
To reduce the amount of mud transported onto public roads by motor vehicles or runoff.
Note: Only applicable for sites greater than 2 acres In size
9" Minimum --/
VL Riprap (D50 = 6")
Non -Woven Geotextile Fitter Cloth
FIGURE C-8
Temporary Vehicle Tracking Control
9-1-99
Urban Drainage and Flood Control District
C-33
DRAINAGE CRITERIA MANUAL (V. 3)
CONSTRUCTION BEST MANAGEMENT PRACTICES
(MgxIMUM)
SILT FENCE INSTALLATION
-NTS-
STEEL OR 2'x4' WOOD POST
(ANCHORED TO FABRIC)
=I
NOTE: EROSION CONTROL MEASURES
SHALL BE MAINTAINED UNTIL
LANDSCAPING IS COMPLETED,
OR AS DIRECTED BY LOCAL
JURISDICTION
1/2H (12-MIN)
1
SECTION
r7&
FABRIC MATERIAL
(ACHORED IN TRENCH)
4'x4' TRENCH
COMPACTED
BACKFILL
FLOW
DETAIL
SILT FENCE EROSION BARRIER
Details provided to District by the City of Broomfield, Colorado
FIGURE C-13
Silt Fence Erosion Barrier
SF
C44 9-1-99
Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL (V. 3)
CONSTRUCTION BEST MANAGEMENT PRACTICES
1.
', 3.2 Mulchin
All disturbed areas must be mulched, or seeded and mulched, within 14 days after final grade is reached
'
on any portion of the site not otherwise permanently stabilized. Areas that will remain in an interim
condition for more than one year should also be,seeded (See Section 3.3.2). An example of mulching is
shown on Figure C-5.
To protect newly seeded areas and to provide temporary cover on other disturbed areas which will not
require temporary revegetation, or which cannot be seeded due to seeding date limitations, a mulch
should be applied consisting of:
;I
1. Clean, weed- and seed -free, long-stemmed grass hay (preferred) or cereal grain straw. Hay is
preferred as it is less susceptible to removal by wind. Mulch should be applied evenly at a rate of
two tons per acre. At least 50 percent of the mulch, by weight, should be ten inches or more in
length.
Mulch must be anchored. This can be accomplished mechanically by crimping or with the aid of
tackifiers or nets. Anchoring with a crimping implement is preferred, and is the recommended
method for all areas equal to or flatter than 3:1. Mechanical crimpers must be capable of tucking
the long mulch fibers into the soil four inches deep without cutting them. An agricultural disk,
while not an ideal substitute, may work if the disk blades are dull or blunted and set vertically.
However, the frame may have to be weighted to afford proper soil penetration.
On small areas sheltered from the wind and from heavy runoff, spraying a tackifier on the mulch
is satisfactory for holding it in place. For steep slopes and other special situations, blankets,
anchored with staples, may be required instead of mulch.
2. Hydraulic mulching shall be limited to those situations where it is too difficult to apply and anchor
a mulch of long-stemmed grass hay or cereal straw; namely, slopes steeper than 3:1
9-1-99
Urban Drainage and Flood Control District
C-21
1!
1
1
1
1
DRAINAGE CRITERIA MANUAL (V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES
CHECK DAM
pennition.
Small temporary dam constructed across a swale or drainage ditch.
Purposes
To reduce the velocity of storrnwater flows and erosion of the swale or ditch.
From: Virginia Soil and Water Conservation Commission, 1985
FIGURE C-21
Check Dam
C-60
9-1-99
Urban Drainage and Flood Control District
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CURB TAPER DETAIL
NO SCALE
6" U.O.N.
'
ESTIMATED CONSTRUCTION SCHEDULE
1.
Survey and stake the drainage structures, detention area and the limited work and
sedimentation barriers(]+ week)
2.
Installation of all sediment and erosion control devices prior to any soil disturbances or in
1
their proper sequence and maintenance until permanent protection is established(]+week)
3.
Place silt fence and construction entrance as shown in plans.
4.
Clear and remove all existing vegetation, buildings, foundations, tanks, curbing,
bituminous and concrete pavements, etc., in those areas where necessary. All remaining
vegetation (if any) to be properly protected and to remain in its natural state. Topsoil to
_
be stripped and stockpiled in approved area. The stockpiles to be protected by a row of --
sedimentation barrier. (2+weeks)
5.
Install sand filter basin, under -drain and outlet structure. Temporary stabilization of those
areas left exposed should be stabilized immediately. (1+days)
'
6.
Layout location
and of the proposed buildings and utilities. (1+ week)
7.
Construction of all proposed utilities, positive drainage from site, and footings and
foundation. (2+weeks)
'
8.
Construction of main structure (ongoing)
9.
Subgrade to be applied following rough grading and installation of improvements in
'
order to stabilize pavement areas. (1+weeks)
10.
Construction of proposed curbs. (2 days)
'
1 1.
Paving of pavement areas. (1 week)
12.
Fine grading of the remainder of the. (1 day)
1'
13.
Stabilization
of the site with permanent vegetative cover and landscaping. (I+week)
'
14.
Removal of temporary sediment and erosion control devices after the completion of fine
grading and permanent stabilization (1+week)
11
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