HomeMy WebLinkAboutSW3221003_Stormwater Report_20230117Stormwater
Management Report
Rockwell ABC
SEA Job # 7783
Summey Engineering
Associates, PLLC
PO Box 968
Asheboro, NC 27204
Phone: 336-328-0902
Fax: 336-328-0902
Email: info@summeyengineering.com
Rockwell ABC
SEA,PLLC
Proiect Overview:
Rockwell ABC is a proposed retail ABC store with associated driveways and parking areas.
The site is located at 320 E. Main Street, Rockwell, NC in Rowan County NC. The project parcel
is approximately 1.52 acres and is currently a vacant parcel.
The soils on site are entirely Cecil -Urban land complex, Hydrologic Soil Group(HSG) B. There
are no floodplains on site per NC FIRM Panel 3 7105 68500J. Per USGS topographic maps there
are not jurisdictional features located on the project site. The entire site drains to Second Creek, a
part of the Yadkin Pee -Dee River Basin.
Stormwater Requirements:
This project must comply with stormwater rules set forth by NCDEQ. The project must provide
stormwater treatment for the first 1" of rainfall. Stormwater outlets must be adequately sized to
pass the larger storm events.
Stormwater Treatment:
One permanent closed sand filter has been proposed for stormwater treatment. The proposed
BMP has been adequately sized to provide treatment volumes to satisfy all of the runoff
generated from the first 1" of rainfall. The 100-year storm peak flow rate has been calculated and
outlet structures have been sized adequately to pass the 100-yr storm event peak flow. Runoff
volumes above the 1" rainfall event will bypass the sandfilter treatment chamber by means of a
bypass orifice.
The project as proposed, meets all the stormwater requirements set forth by the NCDEQ. Refer
the to "Attachments" for more information.
Rockwell ABC
SEA,PLLC
Attachments:
Maps
- DA-1 Proposed Site Impervious Area Map
- DA-2 Sediment Basin Drainage Area Map
- DA-3 Inlet Drainage Area Map
- DA-4 Sand Filter Drainage Area Map
- Hydrologic Soils Group Map
- NC FIRM Panel 3710565900J
- USGS Maps
- Aerial
- NOAA IDF - Intensity
Calculations
- Water Quality Volume Calculations
- Peak Flow Runoff Calculations
- Baffle Sizing Calculations
- Diversion Ditch Calculations
- Rip Rap Apron Sizing Calculations
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INLET #3 DRAINAGE
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( INLET #4 DRAINAGE
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INLET #5 DRAINAGE
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DRAWING LEGEND
PROPERTY LINE
EXISTING MAJOR CONTOUR
EXISTING MINOR CONTOUR
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DRAWING SCALE
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SEA Job No: E-7783
Date: Wg2 H 2O22
Drawn by. bj�
Checked by: HM5_
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PROPERTY I p N L — — — — — J SAND FILTER DRAINAGE AREA
BOUNDARY �r88 61'
SITE AREA NOTES:
(D
TOTAL SITE AREA: 66,249 SF (1.52 AC)
p r4 PROPOSED IMPERVIOUS AREA: 42,633 SF. (0.98 AC)
r J GRASS: 23,616 SF (0.54 AC)
NORMANDY PRTN LLC, BPC
HOLDINGS LLC
DEED REF: 1393/ 331 I ' BUA % : 64.4% W z
ZONED:B-2 '
0 �9 SAND FILTER DRAINAGE AREAS: Q
a, O BREWER DIL GRASS 5,104 SF (0.12 AC)
DEED REF: IMPERVIOUS 42,633 SF (0.98 AC) W z
ZONED: B-2 z e
Q 1 �, E TOTAL 47,737 SF (1.10 AC) (� � o o
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Y OFF —SITE AREA ' to 0 BYPASS AREAS:
o TO PERMANENT 6 CE J Y
DIVERSION ° J uj v Q "
1 k GRASS 18,512 SF (0.42 AC) W
IMPERVIOUS 0 SF (0.00 ACI M s~�
O TOTAL 18,512 SF (0.42 AC) Z •�
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BREAKDOWN: oC o
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z IMPERVIOUS AREA BUILDING AREA: 6,016 SF
/ SIDEWALK AREA: 2,903 SF
` PARKING AREA: 33,714 SF
BMP IMPV AREA BREAKDOWN:
Ln
w 0 WARNER JACOB D, BUILDING AREA: 6,016 SF
PALEOLOGOS SIDEWALK AREA: 2,903 SF SEA Job No: E-7783
DEED REF: 1349/1E PARKING AREA: 33,714 SF
ZONED: R-1 Date: M/\�CH 2O22
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PERMANENT DIVERSION DRAWAG Drawn by: bj�
— AREA: �_ Checked by. HM5_
TOTAL DRAINAGE AREA: 10,126 SF (0.23 AC) —�— o Sheet
MARTIN JAC I U,
S AINE _
SS SS DEED REF: 1365/371 DA�
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DRAWING SCALE
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Hydrologic Soil Group —Rowan County, North Carolina 3;
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USDA Natural Resources Web Soil Survey 4/26/2022
igliml Conservation Service National Cooperative Soil Survey Page 1 of 4
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Hydrologic Soil Group —Rowan County, North Carolina
Hydrologic Soil Group
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
CfB
Cecil -Urban land
complex, 2 to 8
percent slopes
B
1.4
100.0%
Totals for Area of Interest
1.4
100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long -duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink -swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
USDA Natural Resources Web Soil Survey 4/26/2022
Conservation Service National Cooperative Soil Survey Page 3 of 4
Hydrologic Soil Group —Rowan County, North Carolina
Component Percent Cutoff.- None Specified
Tie -break Rule: Higher
IJSDA Natural Resources Web Soil Survey 4/26/2022
Conservation Service National Cooperative Soil Survey Page 4 of 4
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FLOOD HAZARD INFORMATION NOTES TO USERS SCALE
SEE FIS REPORT FOR ZONE DESCRIPTIONS AND INDEX MAP
THE INFORMATION
DEPICTED ON THIS MAP AND SUPPORTING
DOCUMENTATION
AREALSO AVAILABLE IN DIGITAL FORMATAT
HTTP: FRIS.NC.GOV FRIS
Without Base Flood Elevation BF
Zone A v A99
With BFE or Depth zone Ae AO, Arf VE, AR
SPECIAL FLOOD
— Regulatory Floodway
HAZARD AREAS
HAZARD
— 0.2% Annual Chance Flood Hazard, Areas
of 1% Annual Chance Flood with Average
g
Depth Less Than One Foot orWith Drainage
Areas of Less Than One Square Mlle zone x
Future Conditions 1% Annual
Chance Flood Hazard zone x
OTHERAREAS OF
— Area with Reduced Flood Risk dueto Levee
FLOOD HAZARD
See Notes zone x
OTHER
— Areas Determined to be Outside the
AREAS
0.2% Annual Chance Floodplain zone
- Channel, Culvert, or Storm Sewer
Accredited or Provisionally Accredited
GENERAL
Levee, Dike, or Floodwall
STRUCTURES
Non -accredited Levee, Dike, or Floodwall
BM5510x North Carolina Geodetic Survey bench mark
BM5510 ® National Geodetic Survey bench mark
BM5510'�> Contractor Est. NCFMP Survey bench mark
D�rB3— cross Sectionswith1%Annual Chance
Water Su rface Elevation (BFE)
a- - - - - Coastal Transect
Coastal Transect Baseline
Profile Baseline
Hydrographic Feature
OTHER
Limit of Study
FEATURES
Jurisdiction Boundary
For lbrmation antl a ,about Ibis ma vailable rotluct,a atetl with[his Fl RM:,,I,din ge p,a p ,
hI,[nbcter,mn,0fA FIRM,howmnmerprntluct,n rthe National P(l b,wance27)g Ingeneral,
please a lithe FEMAMap Ub Hm,ion eXm VvAat 1-B]] ny,MAP(1-B]]-33B-2B2])orvisit the FEMAMap
Service COMB) b,iteathttMbpAcfema got. Anaccompanying Flootl Insuance Swtlyreport, Letterof Map
Revision(LOMR)or Letterof Map,1h Cment(LOMA)revisingportio nsofthispanel, antl Ub11lversions of lb
FIRM may be available. Visit tlhe North Carolina Flootlplain Mapping Progam websib at http //www.ncflootlmapscor
or anbc[tlhe FEMA Map Service Center.
Communite, annexing Iantl on atljacent FIRM panels must obtain a current copy of me atljacent panel as well as
the curent FI AM I ntlex. These may be o,db,bd tlirectly from the Map Service Center attlhe number lisRd above.
F.... mmunity antl countywitle map tlate, refer to the Flnntl Insuance St tly report forthl,j ,,Nbtnn.
To tle b—ne If flootl Insurance Is ma113b1e In the community, e,nt3,tynur Insuance agent or all the Natnnal
Flootl Insuance Pmgam at 1-311638-6620.
Base map information shown on this FIRM was provitletl In tligibl format by the North Carolina Flootlplain
Mapping Pmgam (NCFMP). The source of this IU-3ton an be tlebrminetl from the mebtlab available In the
tligital FLOOD tlataba,e antl In the Temnlal Support Dab Notebook TARN).
ACCREDITED LEVEE NOTES TO USERS If an accretlitetl levee nob appear, on thh panel check witlh your Ioa1
3_3b obtain more,nformaenn sum a, the e 4imatetl I ete1 of ro rotitletl which ma exceetlthe
n�[v v t nnp ) y
i�p-g -fl,,d Lmance I _)antl Emergency Acton Plan, on be Ietee ry4em(,) It— a,pavming probdon.
To mitigate flootl risk In resitlual risk areas, property owners antl rb,,db R are encouragetl b c,n,,d,, flootl
antl f,,dproofing o r otherprotectve measures. For more Infornaton on flootl Insuance, Inbastetl
partiesshoultl visit the FEMA Website at hUb//vwwv fema gov/busines—phn— hU,
PROVISIONALLY ACCREDITED LEVEE NOTES TO USERS If a Pavlsnnally Amamtetl Levee (PAL) nob
appears on Uhl, panel, checkwith your I0a1 community b obbin more Information, such rime estmabtl level of
probm p tl(hh y tlh,p n tlE g yA Pl
,y ,)h b rtgb tl t'
reon the
q�l etl lbh tl tltl ry pry h s es 10 f h NFIP gU13t on,
Ifthec 4own tl p tl h ,d tltl If th tl tltl
prov tletl tl h y tl ply hS 65.10 q FEMA II h ry tlon
hazaN tl k f f M1 fl tl tl f h y T g fl tl k
be,
dual k as, property ea antl restl eenmuag tl oc ns tlerflootl uance antl flootlproof ng
r otlher protective measures. For more Inbrmaton on flood I--ce�Interestetl parties shoultl visit the FEMA
Nkbsite at h[qh://. fema go1business/U p/intlex dUn,
LIMIT OF MODERATE WIVEACTION NOTES TO USERS Forsonoe a-31 Flood, zone, the AE Zone
ategory has been tlivitletl by a Limit of M otleate Wave Action (LiM WA). The LiM WA represent, the approximate
antlwaN limit of tlhe 1.Sfoot breaking wave. The effects of wave hazaN, between tlhe VE Zone antl tlhe LiM WA
(or between the shoreline antl the LiM WA for areas where VE Zones are not de
will be similar b, but less
seven than those In be VE Zone.
Limit of Moderate Wave Action (LIMWA)
COASTAL BARRIER RESOURCES SYSTEM (CBRS) NOTE
This map may Inclutle apprortmate bountlarie, of the CBRS to,IU—bonal purposes onry. Flootl Insuance I, not
a all able wh,n CBRS area, to, t—tu thdtare newly builtorsub,bntauy Improvetl onorafbrbe date(,)
Ind btetl0nme nap. Fnr morelUo Wtd0n,ee dclep w.fwegov/habltatconsenat0nrt0as61barherntml, be
FIS Report, or all the U.S. FI,h antl Wiltllife Service Customer Service Center at 1-300-344WI LD.
® CBRS Area Otherwise Protected Area
eMap Pml.crlon:
North Carolina State Plane Pro ection Feet Zone 3200
um Dat. NAD 1983 Horizontal NAVD 1988 Vertical
1 inch = 500 feet 1:6,000
0 250 500 1,000
Feet
Meters
0 75 150 300
PANEL LOCATOR
IREDELL CO U NTY
DAME COUNTY
.
M
1160111111111111
•t CABARRUS COUNTY STANLY COUNTY ;
NORTH CAROLINA FLOODPLAIN MAPPING PROGRAM
NATIONAL FLOOD INSURANCE PROGRAM
9 _OOD INSURANCE RATE MAP
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NORTH CAROLINA
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PANEL 5685
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Panel Contains:
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COMMUNITY CID PANEL SUFFIX
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ROCKWELL, TOWN OF 310214 5685 ..
ROWAN COUNTY 3]0351
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6/16/2009
F THE
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S. GEOLOGICAL SURVEY
ITIreI NCalimTlal Mnp
science for a changing world US 1Opo
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Produced by the United States Geological Survey
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SCALE 1:24 000
ROAD CLASSIFICATION
North American Datum of 1983 (NAD83)
World Geodetic System of 1984 (WGS84). Projection and
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i 1
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0 KILOMETERS 1
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This map is not a legal document. Boundaries may be
-a 1000
500
0 METERS 1000
2000
Ramp
4WD
generalized for this map style. Prate lands within government
rvations may not be shown. Obtain permission before
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Imagery .....................................................NAIP, June 2016 - N-1,er
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FEET
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...as1980
2016
2019
UTM GRID AND 2010 MAGNETIC NORTH
1 Rowan Mills
............................................................................GINS,
Hydrography...............................National Hydrography Dataset, 1899 -
2018
DECLINATION AT CENTER OF SHEET
1
2
3
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Con[ours............................................National Elevation Da[ase[,
Boundaries .............. Multiple sources, see metadata file 2017 -
2008
2018
CONTOUR INTERVAL DATUM
NORTH AMERICAN VERTICAL DATUM OF 1988[A7
4 Chinawetland
Thf
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NOAA Atlas 14, Volume 2, Version 3
' Location name: Rockwell, North Carolina, USA*1441
Latitude: 35.552°, Longitude:-80.4078°
Elevation: 778.29 ft**
source: ESRI Maps
"source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1
Average
recurrence interval (years)
1
2
5
10
25
5D
100
200
50D
10D0
4.70
5.57
6.48
7.12
7.84
8.30
8.71
9.06
9.43
9.66
5-min
(4.34-5.11)
1 (5.14-6.06)
(5.96-7.06)
(6.53-7.73)
(7.15-8.48)
1 (7.55-9.00)
1 (7.88-9.44)
(8.16-9.83)
(8.41-10.2)
1 (8.56-10.5)
3.76
4.45
5.19
5.69
6.24
6.61
6.92
7.18
7.46
7.61
10-min
(3.47-4.08)
(4.10-4.85)
(4.78-5.65)
(5.23-6.18)
(5.70-6.76)
(6.01-7.16)
(6.26-7.51)
(6.47-7.79)
(6.65-8.10)
(6.74-8.27)
3.13
3.73
4.38
4.80
5.27
5.58
5.83
6.04
6.26
6.37
15-min
(2.89-3.40)
(3.44-4.06)
(4.03-4.76)
(4.40-5.21)
(4.82-5.71)
(5.07-6.05)
(5.28-6.32)
(5.44-6.56)
(5.58-6.80)
(5.64-6.92)
30-min
1 8 2533
2. 8--J2881
2. 6-3.38
3. 9 3878
3.579.23
3.82 4055
4.04 4?84
4. 4 5010
4. 45841
4.57-1661
1.34
1.62
1.99
2.27
2.6D
2.85
3.08
3.30
3.57
3.76
60-min
(1.23-1.45)
(1.49-1.76)
(1.84-2.17)
(2.08-2.46)
(2.38-2.82)
(2.59-3.09)
(2.79-3.34)
(2.97-3.58)
(3.19-3.88)
(3.33-4.09)
0.776
0.938
1.17
1.33
1.55
1.71
1.87
2.02
2.22
2.36
2-hr
(0.712-0.846)
(0.860-1.03) 11
(1.07-1.27)
1 (1.22-1.45) 11
(1.41-1.69)
1 (1.55-1.86)
1 (1.68-2.04)
(1.80-2.20)
(1.96-2.42)
(2.06-2.58)
0.550
0.664
0.829
0.953
1.12
1.25
1.37
1.50
1.66
1.79
3-hr
(0.505-0.601)
(0.610-0.726)
(0.760-0.906)
(0.871-1.04)
(1.02-1.22)
1 (1.13-1.35)
1 (1.23-1.49)
1 (1.33-1.62) 11
(1.46-1.80)
1 (1.56-1.94)
0.335
0.403
0.503
0.580
0.684
0.765
0.846
0.929
1.04
1.13
6-hr
(0.307-0.366)
(0.370-0.441)
(0.461-0.550)
(0.530-0.633)
(0.620-0.743)
(0.689-0.830)
(0.757-0.918)
(0.823-1.01)
(0.909-1.13)
(0.972-1.22)
0.197
0.237
0.298
0.345
0.410
0.462
0.515
0.570
0.646
0.705
12-hr
(0.181-0.215)
(0.218-0.260)
(0.273-0.325)
(0.316-0.377)
(0.372-0.445)
(0.416-0.501)
(0.460-0.557)
(0.503-0.616)
(0.560-0.696)
(0.603-0.760)
0.118
0.142
0.178
0.206
0.245
0.275
0.306
0.338
0.382
0.417
24-hr
(0.109-0.127)
(0.132-0.153)
(0.166-0.192)
(0.192-0.222)
(0.227-0.263)
(0.254-0.296)
(0.282-0.329)
(0.311-0.364)
(0.350-0.412)
(0.380-0.449)
2-day
0. 6 -0 073
0.077--0 089
0. 96 0..1110
0.110-0.127
0.130-0..1150
0.145-0.168
0.16110.186
0.1776-0.206
0.198-0..232
0.214-0252
0.049
0.058
0.072
0.083
0.098
0.110
0.122
0.134
0.151
0.164
3-day
(0.045-0.052)
(0.055-0.063)
(0.067-0.077)
(0.077-0.089)
(0.091-0.105)
(0.102-0.118)
(0.113-0.130)
(0.123-0.144)
(0.138-0.162)
(0.150-0.176)
0.039
0.046
0.057
0.066
0.077
0.086
0.096
0.105
0.119
0.129
4-day
(0.036-0.041)
(0.043-0.049)
(0.053-0.061)
(0.061-0.070)
(0.072-0.082)
(0.080-0.092)
(0.088-0.102)
(0.097-0.113)
(0.109-0.127)
(0.118-0.138)
0.025
0.030
0.037
0.042
0.049
0.055
0.061
0.067
0.075
0.081
7-day
(0.024-0.027)
(0.028-0.032)
(0.035-0.039)
(0.039-0.045)
(0.046-0.052)
(0.051-0.058)
(0.056-0.064)
(0.062-0.071)
(0.069-0.080)
(0.074-0.087)
0.020
0.024
0.029
0.033
0.038
0.042
0.046
0.050
0.056
0.060
10-day
(0.019-0.022)
(0.023-0.026)
(0.027-0.031)
(0.031-0.035)
(0.036-0.040)
(0.039-0.044)
(0.043-0.049)
(0.047-0.053)
(0.052-0.059)
(0.056-0.064)
0.014
0.016
0.019
0.021
0.024
0.027
0.029
0.032
0.035
0.038
20-day
(0.013-0.014)
(0.015-0.017)
(0.018-0.020)
(0.020-0.022)
(0.023-0.026)
(0.025-0.028)
(0.027-0.031)
(0.030-0.033)
(0.033-0.037)
(0.035-0.040)
0. 111
0.013
0.015
0.017
0.019
0.021
0.022
0.024
0.026
0.028
30-day
(0.011-0.012)
(0.013-0.014)
(0.015-0.016)
(0.016-0.018)
(0.018-0.020)
(0.020-0.022)
(0.021-0.024)
(0.023-0.025)
(0.025-0.028)
(0.026-0.029)
0.009
0.011
0.013
0.014
0.015
0.017
0.018
0.019
0.020
0.021
45-day
(0.009-0.010)
(0.011-0.011)
(0.012-0.013)
(0.013-0.014)
(0.015-0.016)
(0.016-0.017)
(0.017-0.018)
(0.018-0.020)
(0.019-0.021)
(0.020-0.022)
0.008
0.010
0.011
0.012
0.013
0.014
0.015
0.016
0.017
0.018
60-day
(0.008-0.009)
(0.009-0.010)
(0.011-0.012)
(0.012-0.013)
(0.013-0.014)
(0.014-0.015)
(0.014-0.016)
(0.015-0.017)
(0.016-0.018)
(0.017-0.019)
Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90 % confidence interval. The probability that precipitation frequency estimates (for a
given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not
checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
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PF graphical
Summey Engineering Associates, PLLC
Project: Rockwell ABC
Job Number: E-7783
WQV Sizing Calculations
Simple Method Runoff Volume
On Site Drainage Area
Type Area
Grass/Woods 0.12 AC
Impervious 0.98 AC
Total Drainage Area (A) 1.1 AC
Impervious Fraction (IA) 0.890909
Runoff Coefficient (Rv) _ .05 + 0.9*IA
Rv 0.851818
Design Storm (RD) 1 in
Design Volume (DV)=3630*Rp*RV*A*0.75
DV 2550.983 cf
Surface Area Prov. 600 sf
Depth Required 4.251638 ft
Volume Provided 2,700 cf
Percent of Full Size 105.8416
Temporary Pool Sizing
Volume Total Volume
Elev. Area (sf)
(cf) (cf)
754 600 0
0
755 600 600
600
756 600 600
1,200
757 600 600
1,800
758 600 600
2,400
758.5 600 300
2,700
Total Volume
2,700 cf
ummey Engineering Associates, PLLC
Project: Rockwell ABC
Job Number: E-7783
Peak Flow Calcultions Calculations
Rational Method Runoff Calculation
Total Drainage Area
Type Area
Grass/Woods 0.12 AC
Impervious 0.98 AC
Total Drainage Area (A) 1.1 AC
C-Value 0.823636
I -Intensity 8.71 in/hr(100-yr 5 min)
Q=C*I*A
Q 7.89126 CFS
Outlet Orifice Size 24"
Summey Engineering Associates, PLLC
Project: Rockwell ABC
Job Number: E-7783
Baffle Calculations
Orifice Diameter 4 in
Orifice Area (A) 0.08727 sf
Driving Head(HO) 4.5 ft
(Ho)/3 1.5 ft
Gravity (g) 32.2 ft/sec'
CD 0.6
Orifice Equation
Q =CD * A* (2 g HO)0.s
* Ho/3 is used to compute drawdown.
Ql 0.514621 cfs (1-4" WHEEP HOLE)
Number of Orifices 20
Provided Q 10.29241 cfs
QPEAK 7.891 CFS (100 YR STORM)
I
_PROJECT: E-7783 Rockwell ABC
OUTLET: 24" RCP - BMP OUTLET PIPE
MAX VELOCITY = 7.9 CFS
0
I
1
-3*Do = 6 FT
La=8FT
W=6FT
d50=0.5FT
dMAX = 0.75 FT
THICKNESS = 1.5 FT
3D�
Outlet W = Do + 0.41-a 120
pipe
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Figure 8.06b Design of outlet protection from a round pipe flowing full, maximum tailwater condition (Tw >_ 0.5 diameter).
Summey Engineering Associates, PLLC
Project: Rockwell ABC
Job Number: E-7783
Channel Flow Equations
Permanent Ditch 1 - Construction Phase
Hydraulic Radius
R = A/Pw
0.548232
Area
A =
3 sf
Wetted Perimeter
Pw =
5.472136 ft
Channel Slope
S =
0.05 ft/ft
Mannings Coeff.
n =
0.02
Trapazoidal Ditch
Bottom Width
1 ft
Side Slope
2 :1
Top Width
5 ft
Depth
1 ft
Manning Equation
Q = (1.49/n)*A*R2/3*Ss/2
Q = 33.48 cfs (Ditch Maximum)
Drainage Area
Type Area (AC) C
Grass/Woods 0.00 0.2
Impervious 0.23 0.9
Q =CIA
C 0.90
1 7.12 in/hr (10 yr - 5 min Storm)
A 0.23 ac
Q 1.47 cfs (Max Required)
Depth of Flow 0.214 ft (@ required Flow)
Q
1.4762 cfs
A
0.305592 sf
R
0.15615
Pw
1.957037 ft
Top Width
1.856 ft
Outlet Velocity (V)= Q/A
V
4.830624 ft/s
LINER IS REQUIRED
Summey Engineering Associates, PLLC
Project: Rockwell ABC
Job Number: E-7783
Channel Flow Equations
Permanent Ditch 1 - Post Construction
Hydraulic Radius
R = A/Pw
0.548232
Area
A =
3 sf
Wetted Perimeter
Pw =
5.472136 ft
Channel Slope
S =
0.02 ft/ft
Mannings Coeff.
n =
0.1
Trapazoidal Ditch
Bottom Width
1 ft
Side Slope
2 :1
Top Width
5 ft
Depth
1 ft
Manning Equation
Q = (1.49/n)*A*R2/3*Ss/2
Q = 4.23 cfs (Ditch Maximum)
Drainage Area
Type Area (AC) C
Grass/Woods 0.00 0.2
Impervious 0.23 0.9
Q =CIA
C 0.90
1 7.12 in/hr (10 yr - 5 min Storm)
A 0.23 ac
Q 1.47 cfs (Max Required)
Depth of Flow 0.614 ft (@ required Flow)
Q
1.472777 cfs
A
1.367992 sf
R
0.365198
Pw
3.745891 ft
Top Width
3.456 ft
Outlet Velocity (V)= Q/A
V
1.076598 ft/s