HomeMy WebLinkAboutCopperleaf Sub - Storm Drainage ReportPrepared For:
Providence Properties, LLC
ACHD,
City of Meridian
Engineers . Surveyors . Planners
Copperleaf Subdivision
Meridian, Idaho
Storm Drainage Report
Prepared By:
Kerby Kirkham, P.E.
Prniprt Engin Per
KM Engineering, LLP
9233 West State Street
Boise, ID 83714
208.639.6939
kkirkham@kmengllp.com
October 18, 2013
Project No: 13-052
TABLE OF CONTENTS
Introduction...................................................
Project Description ........................................
Site Description .................................................
Scope and Methods ........................................
Existing Drainage Conditions ............................
Proposed Drainage Conditions and Analysis ....
Sand and Grease Trap .......................................
Inlet and Gutter Capacities ...............................
Infiltration Basin w/ Forebay Calculations........
Summary...........................................................
APPENDICES
Appendix A - Figures
Figure 1 - Vicinity Map
Figure 2 - Post -Development Drainage Map
Appendix B - Calculations
25—year and 100 -year storm Flow and Volume Calculations
Sand and Grease Trap Calculations
Infiltration Basin w/ Forebay Calculations
Appendix D - Geotechnical Engineering Report
Geotechnical Engineering Evaluation (7/9/2013)
INTRODUCTION
The purpose of this report is to show that the storm drainage facilities for the proposed
Copperleaf Subdivision (Project) are designed to meet Ada County Highway District
(ACHD), City of Meridian, as well as the water quality requirements of the Idaho
Department of Environmental Quality (DEQ) standards. This report has been prepared
at the request of the developer, Providence Properties, LLC.
PROJECT DESCRIPTION
The Project consists of a residential subdivision that includes 20 lots: 16 single-family
residential lots and 4 common lots. The proposed improvements to the site include
roadways, sidewalks, lot grading, and site utilities.
SITE DESCRIPTION
The 2.86 -acre Project site is located at 4405 East Ustick Road in Meridian, Idaho. See
Appendix A, Figure 1 for a vicinity map of the project. The existing parcel of land
includes two existing residences located on the north portion of the site that will be
removed and are not a part of the development. The existing topography onsite is
gently sloping terrain with slopes generally around 1%. The majority of the existing
Project site is undeveloped and consists primarily of cultivated soils with less than 20%
coverage.
SCOPE AND METHODS
The Rational Method is the standard method for small catchments that was used to
calculate pre -development and post -development peak runoff rates and runoff
volumes. The Rational Method provided in the ACHD calculation sheets were used to
calculate the storm water volumes and flow rates for this project, see Appendix C -
Calculations. Flow rates and storm volumes were established for each basin for the 25 -
year and 100 -year storms. Refer to Appendix B, Table 1 - Peak Flow Rates and Runoff
Volumes, for a summary of flow rates and runoff volumes. Calculations for the sand and
grease trap, inlet and gutters, infiltration basin with forebay, and storm pipes were
completed to verify capacity.
EXISTING DRAINAGE CONDITIONS
The pre -project watershed consists of one drainage basin that is primarily
undeveloped, cultivated soils with less than 20% coverage. The flow path for the
existing drainage basin involves overland sheet flow from the northeast corner to the
southwest corner of the site. There are no existing storm drainage facilities in place
to reduce the peak runoff volumes.
PROPOSED DRAINAGE CONDITIONS AND ANALYSIS
The proposed drainage system improvements consist of roadway gutters, inlets, sand
and grease trap, infiltration basin with forebay, and storm pipe network.
1
The tributaries for the post development site include the front half of the lots and the
proposed roadway, curb and gutter, and sidewalks. Storm water runoff consists of
overland sheet flow over short grass and then is conveyed with curb and gutter to catch
basin inlets, before entering a pipe network. Once runoff reaches the pipe network, it is
conveyed to the sand and grease trap used as a pretreatment facility before entering
the infiltration basin forebay and pond. For the 100 -year peak flow rates a bypass pipe
has been designed to route runoff directly to the primary pond. Refer to Appendix B,
Calculations, for peak runoff rates and volumes..
For this project, we are tying into an existing retention facility that was constructed with
the Redfeather Subdivision No. 2. We are not modifying any of the existing facilities but
have expanded the existing facility to accommodate the additional flows generated
from our Project. Refer to Appendix B, Calculations for new runoff volumes and pond
sizing.
SAND AND GREASE TRAP
The sand and grease trap (SG#1) is used as a pretreatment facility for the water quality
2 -year storm event. The sand and grease trap shall be a 1000 Gallon Boise Vault, or
approved equal, and has been sized for the water quality storm. For the 100 -year peak
flow rates a bypass pipe has been designed to route runoff directly to the primary pond.
Please refer to Appendix B - Sand and Grease Trap Calculations.
INLET AND GUTTER CAPACITIES
The catch basin inlets will be built per the details shown on the civil construction
plans. There are a total of two inlets. Based on our calculations, all inlets will require
a single sump grate inlet to intercept the flows.
INFILTRATION BASIN WITH FOREBAY
The infiltration basin (Pond -1) will be built per the details shown on the civil
construction plans. Based on our calculations, the infiltration basin is adequately sized
to ensure that no ponding occurs on the surface and that 90% of the storm event drains
in 24 -hours. The Geotechnical Engineering Evaluation prepared by STRATA, Inc. dated
July 9, 2013 didn't encounter ground water and recommends that a seasonal high
groundwater level of 14 feet below existing grade be assumed for storm water facility
design.
Once the size of the infiltration basin was calculated, the time necessary for 90% of the
water quality and 100 -year storm events to be infiltrated into the ground was calculated
at less than 24 hours for the forebay and pond. The Geotechnical Engineering
Evaluation measure an infiltration rate of 8 inch/hour at a depth of 4 to 6 feet below
existing grade, which was used in the design of the infiltration basin.
The calculations included with this report show the volume that is required to be
retained for the 100 -year storm, the volume that is provided by the infiltration basin,
2
and the infiltration through the bottom of the basin, refer to Appendix B — Infiltration
Basin with Forebay Calculations.
SUMMARY
This report determines that the Project storm water design sizing and analysis conforms
to ACHD and the City of Meridian storm water design criteria. The post -development
storm water runoff for half of the proposed residential lots, roadway, curb and gutters,
and sidewalks should be completely retained onsite through the proposed infiltration
basin pond and forebay, thus reducing the 25 -year and 100 -year peak flow rates and
runoff volumes when compared to pre -development, refer to Appendix B, Table 1- Peak
Flow Rates and Runoff Volumes.
3
APPENDIX A - FIGURES
L6
—x— —x— —x— —x
z
- O
Lr)O w
2 �
mo_ zQ
Ln z or
LLQ oz
Co
BASIN 1
d \ a C w a
o
aLU2
NORTH SHARON AVENUE
to
0 0
® W BASIN Z -
W
0 � F
LU
® / /
elam
` ENGINEERS. SURVEYORS. PLANNERS
- - - BOISE, IDAHO (208)639-6939
OATS: 10/18/13
13-052
® � ® PROJECT: 13-052
1 OF 1
0 20 40 80 120
Plan Scale
APPENDIX B - CALCULATIONS
POST -DEVELOPMENT 25 -YR AND 100 -YR STORM
FLOW AND VOLUME CALCULATIONS
ACHD Calculation Sheet for Finding Peals Discharge/Volume - Rational Method
NOTE: This worksheet is intended to be a guideline to standard ae ACHO checking of drainage calculations and shall not replace the Engineer's calculation methodology. These
calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted.
Steps for Peal<Dscharge Rate usmgthe Ramona l Method ca lcu Iated for pest -project
Calculate Post-ProjectFlows(for pre -project flows, increase number of storage Facilities to create new tab)
User input in yellow cells. To accept default value type= in yellow cell and point to computed cell f
1 Project Name Capperleaf Subdivision otal Area
2 Is area drainage basin map provided? Yes
(map must be included with stormwater calculations)
3 Enter Design Storm For Volume (100 -year per ACHD policy) 100
4 Enter number of storage facilities (25 max) 1
fltrb+�eh�,., a�n.e Rnhhado� n
5 Area of Drainage Subbasin (SF or Acres) SF
Acre!
6 Determine the Weighted Runoff Coefficient (C)
C=[(Q%AS)+(C2xA2)+(CnxAn)]/A Weighted AVE
Subbasin
I
Subbasin
Subbasin
Subbasin
QlA
Subbasin
Subbasin
Subbasin
Subbasin
1
Subbasin 2
3
4
5
Subbasin 6
7
a
9
30
52,068
V
3,665
3,665 ftc
V= Ci (Tc-601Ax3600
12 Calculate Vwq (for sizing WQ facilities)
1.20
Enter Percentile Storm I(80th percentile =0.34 in)
801th
0.34 in
Enter WQ Volume IV,= Cxi(from line above) xAx3600)
VwR
1,083
1,083 fC
0.74
cfs
0.74
7 Calculate Overland Flow lime of Concentration In Minutes (Tc) or use default 10 Usar Calculate
min
B Determine the average rainfall intensity(I) from IDF Curve based on
I
3.11
3.11 m/hr
9 Calculate the Post -Project peak discharge(QPeak)
QlA
2.75
2.75 c15
IU Calculate peak Qwq(uses 2 -yr storm)
Own
1.07 cis
Industrial had Commercial
Lighter,.,
Heavy areas
(used for SIG Trap throat velocity, WQstorm conveyance system sizing )
Park, cemeteries-
010-O25
Playgrounds
0.20-0.35
Railroad yard ,ices
0.20-0.40
Unimproved areas
11 Calculate tota l runoff vol(V)(for sizing prima ry storage)
V
3,665
3,665 ftc
V= Ci (Tc-601Ax3600
12 Calculate Vwq (for sizing WQ facilities)
Enter Percentile Storm I(80th percentile =0.34 in)
801th
0.34 in
Enter WQ Volume IV,= Cxi(from line above) xAx3600)
VwR
1,083
1,083 fC
13 Detention: Approved Discharge Relate Surface Waters (if applicable)
cfs
14 Volume Summary
Surface Storage: Pond
WQ Pond Faraday +l5'Msediment V 1,245 1,245 it,
Primary Treatment/Storage Basin V 2,582 2,582 ft'
Subsurface Storage: Seepage Bed
Volume Without Sediment Faacr V 3,665 3,665 ft'
See BMP045eepage Bed for Design Volume With Sediment
P:\13-052\Documents\Reports\ACHD ED Calc 08-29-13 prelim Version 5.6, Ju1y2013
Estimated Runoff Coefficients for various Surfaces
Type ofsoriace
Runoff Coefficients "e"
Business
Downtown areas
Urban neighborhood areas
O.70-095
050-o 70
Resldentlal
Single-family
MuhHamilq
035-050
0.60-0.75
Residental(rural)
0.25-0.40
Apartment dwelling areas
070
Industrial had Commercial
Lighter,.,
Heavy areas
0.80
090
Park, cemeteries-
010-O25
Playgrounds
0.20-0.35
Railroad yard ,ices
0.20-0.40
Unimproved areas
0.10-0.30
Streets
ssna�n
Hoe
10/18/2013,10:52 AM
ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method
NOTE: This worksheet is Intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These
calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted.
User input in yellow cells. To accept default value type= in yellow cell and point to computed cell
1 Project Name Copperleaf Subdivision Basinl
2 Is area drainage basin map provided? Yes
(map must be Included with stormwatercalculations)
3 Enter Design Storm For Volume(100-yearper ACHD policy) 100
4 Enter number of storage facilities (25 max) 1
5 Area of Drainage Subbasin (BE or Acres) SF
Acre:
6 Determine the Weighted Runoff Coefficient (C)
C=[(Cl%A1)+(C2xA2)+(CnxAn)]/A Weighted Avt
Click to Show More Subbacihs ❑
Subbasin
Determine the average rainfall intensity (i) from IDF Curve based on
Subbasin
Subbasin
Subbasin
in/hr
Subbasin
Subbasin
Subbasin
Subbasin
1
Subbasin 2
3
4
S
5ubbasin 6
7
8
9
10
31,194
Vee
amF+it
Oo5
11
Calculatetotal runoffvol (V) (for sizideprimary storage)
V
2,196
2,196
ft'
0.72
V = Ci (Tc=60)Ax3600
12
Calculate Vwq (for sizing WO facilities)
0.74
Enter Percentile Storm l (80th percentile = 0.34 in)
80th
0.34
in
Enm,WQVolume(V,a=Cxi (fmmlineabove)xAn3600)
0.74
649
649
ft
13
Detention: Approved Discharge Rate to Surface Waters (if applicable)
cfs
7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 user calculate =
min
8
Determine the average rainfall intensity (i) from IDF Curve based on
1
3.11
3.11
in/hr
9
Calculate the Post -Project peak discharge(QPeak)
Qp-k
—376's,cis
Volume Without Sediment Fedor V
2,196 2,196 ft'
lu
Calculate peak Qwq(uses 2 -yr storm)
Owe
0.64 chs
020-0.35
Railroad yard areas
0,20-0.-00
]used for S/G Trap throat velocity, W Q storm conveyance system sizing )
0.10-0.30
Vee
amF+it
Oo5
11
Calculatetotal runoffvol (V) (for sizideprimary storage)
V
2,196
2,196
ft'
V = Ci (Tc=60)Ax3600
12
Calculate Vwq (for sizing WO facilities)
Enter Percentile Storm l (80th percentile = 0.34 in)
80th
0.34
in
Enm,WQVolume(V,a=Cxi (fmmlineabove)xAn3600)
Vwa
649
649
ft
13
Detention: Approved Discharge Rate to Surface Waters (if applicable)
cfs
14 Volume Su.inary
Type of S.rfa.
Surface Storage Pond
Business
Downtown am.
Urban nelghborhoodcmxc
V✓Q Pond ForebaV+15%sediment V
746 746 ft'
Primary Treaument/Storage Basin V
1,547 1,547 ft'
Subsurface Storage: Seepage Bed
Apartment dwelling areas
Volume Without Sediment Fedor V
2,196 2,196 ft'
See BMP045eepage Bed for Design Volume With Sediment
Parks, cemeteries
P:\13-052\Documents\Reports\ACHD 5D Cain 08-29-13 prelim Version 5.6, July 2013
Caimatetl Runoff coefficients for %manus surfaces
Type of S.rfa.
Runoff CoeHrients "C"
Business
Downtown am.
Urban nelghborhoodcmxc
0.70-0.95
030-070
Residential
Single-family
Mvlii-family
035-0.50
0.60-075
Resdennal;rural)
025-0.40
Apartment dwelling areas
0.70
Industria; and Commerual
Light areas
Heavy areas
0.80
090
Parks, cemeteries
0.10-0.25
Playgrounds
020-0.35
Railroad yard areas
0,20-0.-00
Unimproved areas
0.10-0.30
Vee
amF+it
Oo5
10/18/2013, 10:52 AM
ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method
NOTE: This worksheet is intended to be a guideline to standardize ACRD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These
calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted.
Steps for Peal, Discharge Rate using the Rational Method calculated for Post project
Calculate Post -Project Flows (for pre -project flows, increase number of storage facilities to create new tab)
User input in yellow cells. To accept default value type = in yellow cell and point to computed cell
1 Project Name Copperleaf Subdivision Basin 2
2 Is area drainage basin map provided] Yes
(map must be included with storm water calculations)
3 Enter Design Storm For Volume (100 -year per ACHD policy) 100
4 Enter number of storage facilities. (25 max( 1
Clickto5hoWMore5ubbasins ❑
7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 user Calculate
min
8 Determine the average rainfall intensity (i) from l DF Curve based on
Subbasin
3.11 3.111n/hr
Subbasin
Subbasin
Subbasin
10 Calculate peak Qwq(uses 2 -yr storm)
Subbasin
Subbasin
Subbasin
Subbasin
Industrial and Commercial
ughtareas
Heavyareas
1
Subbasin 2
3
4
5
Subbasin 6
7
8
9
10
5 Area of Drainage Subbasin(SF or Acres) SF
20,874
Enter Percentile Storm I(80th percentile = 0.34 in)
80th 0.34 in
Enter W QVolume (Vwo= CA (from line above) xAx3600)
VWQ
434 434 ft'
13 Detention: Approved Discharge Rate to Surface Waters (if appiiable)
ds
Acres
0.48
6 Determine the Weighted Runoff Coefficient (C)
0.74
C=((C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg
0J4
7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 user Calculate
min
8 Determine the average rainfall intensity (i) from l DF Curve based on
1
3.11 3.111n/hr
9 Calculatethe Post -Project peak discharge(QPeak)
On.k
1.10 1.10 cis
10 Calculate peak Qwq(uses 2 -yr storm)
Owe
0.43 cfs
(used for 5/G Trap throat velocity, WQ storm conveyance system sizing )
0.70
Industrial and Commercial
ughtareas
Heavyareas
0.80
0:90
Parlor, cemeteries
0.10-0.25
11 Calculate tota l runoff vol IV)(fo r sizing primary std rage)
V
1,469 1,469 its
V = Ci (Tc=60]Ax3600
Unimproved areas
o.10-0.30
12 Calculate Vwq (for sizing WO facilities)
nes
Enter Percentile Storm I(80th percentile = 0.34 in)
80th 0.34 in
Enter W QVolume (Vwo= CA (from line above) xAx3600)
VWQ
434 434 ft'
13 Detention: Approved Discharge Rate to Surface Waters (if appiiable)
ds
14 Volume Summary
Surface Storage: Pond
WQ Pond Forebay+l5°6 sediment V 499 499 ft'
Prima ry Treatme mi Storage Basin V 1,035 7035 ft'
Subsurface Storage: Seepage Bed
Volume Without Sail [me nt Factor V 1,469 1,469 ft°
See BhAP04Seepage Bed fol Design Volume With Sediment
P:\13-052\Documents\Reports\ACHDSDCalc_08-29-13 prelim Version 5.6,Ju1y2013
estimated Runoff Coefficients for Various surfaces
Type of Surface
Runoff Coefficients "C"
Business
Downtown areas
Urban neighborhood areas
0.70-095
050-0.70
Residential
Single-famdy
Mulb-family
0.35-050
0.60-0.75
Re4denbal(rural)
0.25-0.40
Apartment dwelling areas
0.70
Industrial and Commercial
ughtareas
Heavyareas
0.80
0:90
Parlor, cemeteries
0.10-0.25
Playerounde
020-035
Railroad yard area,
0.20-0.40
Unimproved areas
o.10-0.30
S ee
G�nF�I}
nes
10/18/2013,.10:52 AM
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SAND AND GREASE TRAP CALCULATIONS
ACHD Calculation Sheet for Sand/Grease Traps
NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the
Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must
result in facilities that meet or exceed these calculations in order to be accepted.
User input in yellow cells. To accept default value type = in yellow cell and point to computed cell
1 Project Name Copperleaf Subdivision -Total Area
1RIM aInun#r4&IJl2
1
ence for Throat widths (inch)
Baffle
Throat
Boise
Velocity
Is the
Vault Size
Number of
Peak Flow
Spacing
width
Area (it')
0.5 fps
Velocity
G
S/G Traps
Q-cfs
(inch)
(inch)
n/a
max.
ok?
1000 G
1
1.07
20
48
6.67
0.16
ence for Throat widths (inch)
10/18/2013, 10:57 AM
P:\13-052\Documents\Reports\ACHD SD Calc 08-29-13 �te&nn 5.5, April 2013
ADS
Boise
Lar -ken
WQU,
Vault
BMP 16
G
48.0
50.5
n/a
G
60.0
61.5
n/a
1000
n/a
n/a
60
1500
n/a
n/a
60
10/18/2013, 10:57 AM
P:\13-052\Documents\Reports\ACHD SD Calc 08-29-13 �te&nn 5.5, April 2013
INFILTRATION BASIN W/ FOREBAY CALCULATIONS
ACHD Calculation Sheet for Sizing Ponds
NOTE: This worksheet is intended to be a guideline to standardize ACRD checking of drainage alculations and shall not replace the Engineer's
calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or
exceed these calculations in order to be accepted.
__
5 i9 Id%ksf�'ab'fm�bayarrd print thea 52e#bi pnmary SE@rag¢/bre tmerrc basin.
User input in yellow cells. To accept default value type = in yellow cell and paint to computed cell
1 Project Name Copperleaf Subdivision -Total Area
4 Approved
ed Discharge
100 Lines to: ��
5 Weighted Runoff Coefficient C 0.74 creak O.vlRss
6 Area A(Acres) 1.20 by
2 Approved Discharge Rate(if appliable) O.DO Asp
8 1-V Fund Forebay 115% sediment V 1,245 ft,
Toggle between Fan day And Enron, 6-M, enter data end ptlntforaoch
Si4abaE 5&64p1 6aeA,ve
w
a^ �
w
Ma
<..t e
6ID5'ktel
Storm Duration
ftatal
FORbay
RunoffVol
F, 11, Pah
9 Select Forebay Shape
Total
Discharge
3 -Rectangle
Min
Hr
10 Width of Forebay emblem
W
15,0
it
ft
11 Length of Forebay Bottom
L
20.o
It
12 Side Slopes (HIV)
H/V
3.00
ft/ft
0
13 Enter Bottom Newtimn
0
2633.00
If
ni;
14 Enter Top Be nk Elevation
33
2637.0
it
u
15 Enter Water So -face Elevation(WSE)
0.25
2636.0
it
934
16 Distance Between Fop bay and Primary Basin (blank if na)
0
0.0D
It
30
17 Enter Elevation Germ
1.82
2635.50
ft
.!
18 Enter High Groundwater Elevation
100
2624.00
If
..
19 Min Freeboard Requirement
0.30
0.50
200
0
20 Freeboard Provided
1,045
1.00
Lou
0.66
21 Sand Bottom for Porebay lnfilt.atlmni
1,97]
8
in/hr
Nateinfilhotbn required rJ
Orsign Infiltration Rete, Enter 0 for no Infiltration
180
3.00
0.48
bottom sop"Ily or 0 outflow
22 Sand Whole. Area for Porebay
A.:,u
30
600
1,597
Enter 0 for no Infiltration
(LED
0.30
0.11
2,.856
Storm Duration
ftatal
D
RunoffVol
PMc Val
Pre-Pmj
Discharge
Total
Discharge
Max V01
Read
Min
Hr
in/hr
an,
its
its
ft
fe
f?
0
0.00
0
o.OD
o
0
0
0
0
0
017
3.11
1.07
738
33
0
33
705
15
0.25
2.62
0.90
934
So
0
50
884
30
0.50
1.82
0.0
1,300
100
0
100
1,200
60
1.00
1.15
0.30
1,245
200
0
200
1,045
120
Lou
0.66
0.24
1,97]
400
0
400
1,577
180
3.00
0.48
0.18
2,197
600
0
600
1,597
30
(LED
0.30
0.11
2,.856
1,200
0
1,200
720
12.00
0.19
0.07
3,515
2,400
0
2,400
1,115
1440
24.00
1 0.12
0.04
1 4,394
4,800
1 0 1
4,800
0
Total Design V0l.
Override
1,666
Saved Stage
(R)
Pond
side Slope WltlMat
New Stage (ft) IH -.V) stage(R)
Pond
Lengthat
Stagelft)
Surface
Area A at
Stage ffta)
Saaee
Sunless
Area AAt
Soga(f"I
BAaace
Area A at
,,a(,$)Below
OVERUSE
Volume
Stage (fit)
263300
203.0 3.000
15.0
20.0
300
0
263550
3.00
SEA
$5.0
11050
1,688
2.50 it depth for storage
25 Dnes tprenay nave opntlN/ YES
26 11111 to drain iarahxl 5 6 Ilan,
90%vnlun-il^M hu rts m:nimnrr` I. ..Q(_
P:\13-052\DANmemtl\Reports\ACHDSD Calc_OB-29-13 prelim
1,638
Version 55, April 2013
10/18/2913,10:53 AM
ACHD Calculation Sheet for Sizing Ponds
NOTE: This worksheet fe Intended to be a guideline t0 standardize ACHO checking of drain age calculations and shall not replace the Engineer's
Calculation methadol0gy. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or
exceed these calculations in order to be accepted.
Br Vanm�r3aratiaN aOTpt uithensfaTafiBr primary s[bldgP�YleatlR¢nfbasin
Won input in yellow cells. To accept default value type - in yellow cell and point to computed cell
1 Project Name Copperledf Subdivision - Total Area
2 Enter number of ponds (25 Max) 1
3 Number of Calls(F.rebay.PrimI Primary Only -1) 2
4 DxIApproved
Sam300 Linkto:�
5 Weighted Runoff Coeffident C 0.74 Peakp.VTR55
6 Area A (Act,,) 1.20 ovP3
J Approved Discharge Rate (if applicable) O.00 as
8.2 -Primary Treatment/O.I.I. Basin V 2,582 TP
Toggle compete Foreboyond Primary Basin, anteroom ondpnntforeach
sWsul.v
1Wk may..
K, prew
w
aR z xz
Primary Basin rn.-6.v/
9 Selert Primary Basin Shape 5 -Irregular
10 Width of Primary Basin Bntlom W 0.0
11 Length of Primary Betio Bottom L 0.0
12 Side Slope,(H/V) HIV 3.00 ft/ft ^Or
13 Enter Bottom Elevation 2633.00 h nr
14 Enter Top Bank Elevation 261 it ...I:.
15 Enter Water Surface Elevation(W5E) 2636.00 A _..
16 Distance Between Forebay and Primary Basin l blanlr if ria) 0.00 it uir
17 Enter Elevation Berm 2635.50 ft _,
18 Enter High Groundwater Elevation 2624.00 ft PJI'
19 Mln, Freeboard Requirement 050
20 Freeboard Encoded LF
-
71 Sand Bottom for Primary/S1wI Basin Initiator' a In/hr Note: vifigmtlon re.. redfi
Design Infiltration Pate, Enter 0 f... inOhra0on benowe'bpea293or0 wiffiew
22 Sand Window Area for Primary As.., 373 it, -
Enter 0 for nn Infiltration
23 and Maximum Storage Required
Sturm Duration
1total
Q
Runoff Vol
Pere Vol
Prergj
Oischa rge
Total
Discharge
Max Vol
Regtl
Min
Hr
in/hr
cfs
fe
it,
fe
fts
its
0
0.00
0
0.00
D
a
o
0
0
10
012
3.11
1.68
1,007
41
0
41
966
15
0.25
2.62
1.42
1,277
62
0
62
1,215
30
0.50
1.82
0.98
1,765
124
0
124
AMC
W
120
1.00
2.00
1.15
0.66
0.72
0.34
2,582
2,462
249
497
0
0
249
497
1,965
180
3.00
0.48
0.25
2,720
746
0
746
1,974
360
6.00
0.30
0.15
3,248
1,492
0
1,492
1,756
720
12.00
0.19
0.10
4,261
2,98C
0
2,984
1,283
1440
24.00
0.12
0.06
5,095
5,968
0
5,968
0
Total Design Vol.
Override
2,334
'4 Dept IT S�Raluddns Ip:
Saved Stage
(ft)
Pond Pond
SheStar, V/Idthat Langthat
New Stage (11) (H:Y) Stage(ft) Stage(fu
Surface
Area Aat
Stage(ft')
Saved
Burlade
Area Aat
Stage IR)
suit..
Area Apt
Stage (Fit)
OVERIDE
Volume
Below
Stag.ift)
263300
2633.00 3.000 0.0 BA
Override
0
i
L�A
0.00 ftdepthfmrtarage Smell
L2625 Does Primary/storage lx -cm have rap a city? NO
Tlme to drain ndmary/emmge basin �Y 5 hourt
901 v611I,ne in 24 he,,, minlmum
P:\13-052\DOcu ments\ReportsI SO tale 08 29-13 prelim version 5.5, April 2013
SEE IM,111 6I
Joh,,)AG SAeer
10/1812013, 10155 AM
Client Sheet of
Project Prepared by
Job No. Date
CIO
I
-
_t I
APPENDIX C - GEOTECHNICAL ENGINEERING REPORT