HomeMy WebLinkAboutWPO201200096 Plan - As-built 2023-01-06ROUDABUSH, GALE & ASSOC., Inc.
A PKUFFSSIONAL CORPORATION Serving Virginia Since 1956
January 5th, 2023
John Anderson
Albemarle County
Department of Community Development
401 McIntire Road
Charlottesville, Virginia 22902
RE: Belvedere 2A SWM As-Builts
I hereby certify that to the best of my knowledge and belief the stormwater management
facilities shown on these record drawings reflect the final, constructed condition of the site and
that the stormwater facility has been constructed in substantial accordance with the approved
plans and specifications except where it is shown otherwise. "Certify means to state or declare a
professional opinion based on sufficient and appropriate onsite inspections, material tests, as -
built survey data, and information provided by other professionals and the contractor, conducted
during or after construction." This statement should be interpreted in conjunction with the
accompanying plans titled "Belvedere Phase 2A VSMP As -Built Plan," dated 01/05/2023, where
as -built conditions and field variances from approved plans, within reasonable tolerances, are
recorded. Calculations have been provided with this submittal which verify that the facility meets
its intended functionality based on the as -built information. A summary of these findings are
shown below:
1. The pond currently provides 73,134 cu. ft of storage. This is greater than the design
requirement of 70,320 cu. ft
2. The as -built 2-yr storm peak flow (4.516 cfs) is below that of the pre -developed 2-yr storm
(4.83 cfs)
3. The as -built 10-yr storm peak flow (18.82 cfs) is below the pre -developed 10-yr storm (22.16
cfs)
4. The peak elevation of the 10-yr storm (417.17') is below the emergency spillway elevation
(417.33)
5. The post -developed 100-yr storm peak elevation (417.90') is more than P below the dam crest
elevation (420.0')
999 Second St. SE, Suite 201 Charlottesville, VA 22902 roudabush.com
®ROUDABUSH, GALE & ASSOC., Inc.
A PROFESSIONAL CORPORATION Serving Virginia Since 1956
Signed,
Jimmy L. Taggart, P.E.
For Roudabush, Gale & Associates
999 Second St. SE, Suite 201 Charlottesville, VA 22902
roudabush.com
1
AS -BUILT
HYDROLOGIC/HYDRAULIC CALCULATIONS
FOR
BELVEDERE PHASE 2A RETENTION BASIN
January 5, 2023
Location:
Albemarle County, Virginia
Developer:
New Belvedere, INC
610 West Rio Rd
Charlottesville, VA 22901
Prepared By:
Roudabush, Gale & Associates, INC
999 2°d St SE
Charlottesville, VA 22902
P: 434.977.0205
F: 434.979.1681
Contents:
1. Cover Sheet
2. 2-Yr As -Built Routed O�
3. As -Built 2-Yr Pond Report
a
4. 10-Yr As -Built Routed o U
S. 100-Yr As -Built Routed o Ji y L. Taggart
No.02u,41
I-s'-Z3 f
2
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2023
Wednesday, 0114 / 2023
Hyd. No. 8
Alt 1 (Revised)
Hydrograph type = Reservoir Peak discharge = 4.516 cfs
Storm frequency = 2 yrs Time to peak = 12.68 hrs
Time interval = 1 min Hyd. volume = 119,798 cult
Inflow hyd. No. = 2 - Inflow Hydrograph (SCS Rdat.�d¢skomd) = 414.76 It
Reservoir name = Revised Alternative 1 Max. Storage = 63,147 cult
amrage imitation n
50.00
4000
tioIrN1
2000
Wk
0.00
V 3 t5
Hyd No. 8
Alt 1 (Revised)
Hyd. No 8 -- 2 Year
Q (Cfs)
6000
50.00
40.00
30.00
20.00
10.00
9 12 15 18 21 24 27 30 33 0.00
— Hyd No. 2 Total storage used = 63,147 tuft Time (hrs)
3
Pond Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3DO by Autodesk. Inc. v2023
Wetlnestlay, 01 / a 12023
Pond No. 6 - Revised Alternative 1
Pond Data
Contours -User-defined contour areas Average end area method used for volume calculation. Begining Elevation = 411.00 ft
Stage / Storage Table
Stage (ft)
Elevation (ft)
Contour area (sqft)
Incr. Storage (cuft)
Total storage (cuft)
000
411.00
14,596
0
100
300
412.00
414.00
15,618
15.107
0
15.107
500
41600
17,654
21.105
33272
48,379
700
418 00
23.239
38.759
44.344
87,138
9.00 _
420.00
24.403
47,642
131,482
179,124
Culvert / Orifice Structures
Weir Structures
[A]
[B]
[C]
[PrtRsrl
[A]
[B]
[C]
[D]
Rise (in)
Span (in)
= 15.00
= 1500
4.00
6.00
0.00
Crest Len (ft)
= 12.60
135.00
Inactive
0 00
No. Barrels
= 1
4.00
4
6.00
0.00
Crest EL (ft)
= 416.30
41730
415.DO
0.00
Invert EL (ft)
= 405.07
411.40
4
414.35
0
0,00
Weir Coeff.
Weir Type
= 3.33
= 1
2.60
056
3.33
Length (ft)
= 77,90
0.00
0.00
0 00
Mufti -Stage
= Yes
Broad
ZS degV
-
Slope (%)
= 0.42
0.00
0,00
n/a
No
Yes
No
N-Value
= 012
.013
013
rva
Orifice Coeff.
Multi -Stage
= 060
=
0.60
0.60
0.60
Exfil.(inftrn
= 0.000 (by
Wet area)
n/a
Yes
Yes
No
TIN Elev. (ft)
= 0.00
Stage (ft)
10.DC
B.00
6.00
4.00
2.00
0.00
----- vvo.v auu.0 1000.0 1200.0 1400.0
Total Q
Note CWvaNpriria auNas are.reya4 un4c inW (ic)arie outlet(«Icantrol War nrrsrletlieE faairxe oontftiore Kl asl ( sibnerge«e(s)
Stage / Discharge
Elev (ft)
421 00
41900
417,00
415.00
413-00
411.00
16000
Discharge (cfs)
0
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3139) by Autodesk, Inc. v2023
Hyd. No. 8
Alt 1 (Revised)
Hydrograph type
= Reservoir Peak discharge
Storm frequency
= 10 yrs Time to peak
Time interval
= 1 min Hyd. volume
Inflow hyd. No.
= 2 - Inflow Hydrograph (SCS R4ak-j[ °Ieslellimd)
Reservoir name
= Revised Alternative 1 Max. Storage
Storage Indication method used
]HE
am it
6M
W
Wednesday, 01 / 4 / 2023
= 18.82 cfs
= 12.23 hrs
= 234,926 cuft
= 417.17 ft
= 112,968 cult
Alt 1 (Revised)
Hyd. No. 8 — 10 Year
O a W 15 18 21 24 27 30
Hyd No. 8 — Hyd No 2 1 ' ; Total storage used = 112,968 cult
Q (cfs)
10000
OEM
.e r�
40,00
im
0.00
33
Time (hrs)
Hydrograph Report
Hydraflow Hydrographs Extension for AutodesMt, Civil 3D@ try Autodesk, Inc. v2023 Wednesday 01 14 / 2023
Hyd. No. 8
Alt 1 (Revised)
Hydrograph type
= Reservoir
Peak discharge
= 185.77 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.02 hrs
Time interval
Inflow hyd. No.
= 1 min Hyd. volume
= 2 - Inflow Hydrograph (SCS Rdakfkwlziod)
= 465,034 cuft
= 417.90
Reservoir name
= Revised Alternative 1
Max. Storage
ft
= 129,343 cuft
Storage Indication method used
Q (cfs)
210.00
180.00
1011111
120.00
30.00
M
Alt 1 (Revised)
Hyd. No. 8 — 100 Year
Q (cfs)
210.00
18000
150.00
120.00
nffim
o a 12 15 18 21 24 27
— Hyd No. 8 — Hyd No 2 Total storage used = 129,343 cuft Time (hrs)