HomeMy WebLinkAboutWPO201500033 Plan - As-built WPO VSMP 2019-10-22 PROJA
CIVIL ECT ME
LAND PLANNING
ENGINEERING
August 19th, 2019
John Anderson
Civil Engineer II
Albemarle County
Department of Community Development
401 McIntire Road
Charlottesville, VA 22902
Regarding: Hillbrook Subdivision— SWM Certification Letter
WPO 201500033 - Amendment
Dear Mr. Anderson,
I have performed the necessary surveys and inspections on the stormwater management systems at the
Hillbrook Subdivision. I can confirm that the system has been installed in a manner that meets the overall goal
of the SWM Plan for this development. An as-built analysis has determined the revisions to the approved site
plan, detailed in the SWM As-Built Analysis Letter attached, have been installed correctly and operate in a
manner that meets the approved site runoff and VRRM requirements.
We have completed final inspections of the site and request that the full VSMP bond amount be released.
If you have any questions please email me at justin@shimp-engineering.com or you may call our office at 434-
227-5140.
APPROVED
test Reg.rds, by the Albemarle County
Community Deve pme t Department
Date Q(2-7 (
File nh,J70/�600
vdPo z-D/t d da �
Justi imp, P.E. A)� 6 2
D �d/7 0 (9
Shi Engineering, P.C.
RECEIVED
AU6 2 6 2019
COMMUNITY
DEVELOPMENT
PROJECT MANAGEMENT
SHIMP CIVIL ENGINEERING
LAND PLANNING
ENGINEERING
August 26th, 2019
APPROVED
John Anderson by the Albemarle County
Albemarle Count ent Department
y Community Dev lop
Department of Community Development Date !a Z -
Engineering Department File
c►
vi
Regarding: WPO 201500033 Hillbrook Subdivision SWM As-Built Analysis
Dear Mr. Anderson,
Please find attached a summary of the SWM Plan for the As-Built storm system at Hillbrook Subdivision.
Revisions from approved SWM plan:
1. Revision to the undetained sheet flow area to the east of the site: the area of sheet flow has been
increased in the northeastern portion of the site near lots 2 & 3 because the ditch in the back of lot 3 was
not installed. Instead of being routed to the underground detention, this undetained area sheetflows to the
wooded area at the rear of the lot. This is shown as Drainage Area B and includes 0.03 acres of
impervious disconnection within this area. The SWM Maps, HydroCAD calculations, and the VRRM
spreadsheet have been updated to reflect this revised drainage.
2. Revision to the underground detention at the east of the site near lot 3: This detention now has a 3" drain
that outlets into the open space parcel for the subdivision. This drain outlets to a level spreader, thereby
maintaining the sheet flow condition originally proposed for this BMP.
Items that have not changed, and still comply with the approved SWM plan:
1. The concentrated runoff that flows to the northwest of the site: the as-built condition of this concentrated
runoff still complies with the energy balance equation
2. Simple disconnection where specified in the original plan: downspouts where simple disconnection was
specified have simple disconnection. Please note that it is the individual lot owners responsibility to
maintain this simple disconnection per SWM maintenance agreements
3. The function of the detention pipes at the northwest portion of the site: the detention system functions as
designed.
4. The required total phosphorous reduction: the original plan required treatment for 1.02 lbs TP. This amount
was met with a nutrient credit purchase. The as-built VRRM requirements remain the same.
The as-built SWM analysis methodology has been kept from the original SWM Plan. The rear portion of the site
which outlets into woods had been designed to sheetflow in compliance with 9VAC25-870-66-D. The as-built
conditions achieve this design strategy.
The as-built 10-yr runoff to the wooded area is less than the pre-development 10-yr runoff. Thus, flood
protection requirements have been met. The as-built 1-yr runoff to the wooded area is 0.21 cfs more than the
pre-development 1-yr runoff. This increase in runoff is acceptable because the runoff is entirely sheet flow and
does not concentrate within the wooded area. This runoff will not cause erosion due to the even slopes and
heavy groundcover over which the runoff sheetflows.
Since flood protection requirements have been met, and since the physical condition of the site ensure
sheetflow, this 0.21 cfs increase in sheetflow runoff from the 1-yr storm is acceptable per standards set forth in
9VAC25-870-66-D. Therefore the as-built conditions meet the approved design requirements for SWM
analysis.
Sheetflow Runoff Flow Rates
1-yr(cfs) 10-yr(cfs)
Pre- Post- Pre- Post-
Dev Dev Dev Dev
0.32 0.53 3.29 2.62
If you have any questions please do not hesitate to contact me at michael@shimp-engineering.com or you may
contact Justin Shimp at Justin@shimp-engineering.com or by phone at 434-227-5140.
Best Regard ,
Michael Chandler
Shimp Engineering, P.C.
8/26/2019 Dropbox-Hillbrook Court SWM Facility Inspection-Simplify your life Gr/(-Je e,C;/...r. )0
< Z•Z Hillbrook SWM Fa...n.pdf •••
EX ROUDABUSH, GALE &ASSOCIATES, INC. A
A PROFESSIONAL CORPORATION g t
LAM)SURVEYING Serving Virgnnia Since 1956
ENGINEERING
LAND PIA.NNING LM;INLLR1M DLPARIMENT SCRYLY DLPARTMLN I
172 SOUTH PANTOPS DRIVE,STE.A 914 MONTI('El LO ROAD
JIMI..IALx1ARI.P.E. CHARLO1TESVILLF VA22911 ('HARL.OTTFSVILLE,VA 22902 WILI.IAM J.L.EDBF ITF.R,L.S.
DON FRANCY),P.E. PHONE(434)9794121 PHONE(434)977.0205 BRIAN D.JAMISON.L.S.
DAV ID M.ROBINSON.P.E. FAX(434)979.1681 FAX(434)296.5220 (RISTOPHER C WINTERS,L.S.
AMMY M.GEORGE,PLA INF(YaROUDABUSI LCOM
Date: 13 August 2019
Subject: Hillbrook Detention Facility Inspection
Roudabush Pipe Inspection Services conducted a video inspection of an underground
Stormwater Detention facility on Hillbrook Court in Albemarle County.The facility consisted of
approximately 75 feet of Stormtech MC-4500 Arch style pipe with detention stone base.The arch pipe is
approximately 5 feet wide by 4 feet tall The pipe was accessed through a plastic structure within the pre-
treatment cell between lots 3 and 4
z '
a•,
Image I.Inspection Access Point
There pipe appeared to be in good condition with no obvious cracks,joint separations.or visual
deformities.The arch-type pipe made inspecting for deformation or collapse difficult,but a visual
inspection did not identify any issues.
2 of 2
https.//www.dropbox.com/sh/2noux7ft9nskijy/AACvg0xco52NYW68-VQs7WgHa?d1=0&preview=Hillbrook+SWM+Facility+Inspection.pdf 1/1
V5MF AS -BUILT PLAN FOR
111 LLE3 ROOK
WFO 2015-00033
TMF OG200-00-00-12GOO
RIO D15TKICT, ALBEMARLE COUNTY, VIRGINIA
VICINITY MAP
SCALE: 1 "=21000'
z�
s�
Wa
;K
T:
5-51
S
:00
i.k9`
4f
f
�'µLi3
y...
iJ'A.��'�,y'i R147
f�"y ym3 }ry`�'�� i�':Ag�py( �j dtpmx
IP "w'R 4.4� la��iLl Yll. A`YY {..
Illd�
���♦
\sF'10
NRIO
4r
AAA%� r (J EL A11V
SITE
tiJ
(I � i
�aYi
1 fife NWC) Of)r
Flip
�+' pp
1 2Y'
N t ,�Yd'i
fa
I�
S
0AXA iERF?Ac
I fI}"
d
Imo'41
IMAGE PROVIDED BY GOGGLE MAPS
SHEET INDEX
C I - COVED SHEET
C2 - A5-BUILT PLAN
C3 - SWM DETAILS
C4 - STORM PROFILES
PROPERTY INFORMATION
OWNER: HILLTOP PARTNERS, LLC
P.O. BOX 645
CHARLOTTESVILLE, VA 22902
DEVELOPER: RED DIRT DEVELOPMENT, LLC
P.O. BOX 645
CHARLOTTESVILLE, VA 22902
LEGAL_ REFERENCE: DB 4722 PG 405-419
(414-418 PLAT)
DB 4562 PG 266
TAX MAP 61 PARCEL 126
(2.63 AC TOTAL)
EASEMENT PLAT: DB 5227 PG 146-154
SOURCE OF AS -BUILT
As —Built Survey Provided to Shimp Engineering, P.C. on 10/28/2016
By: Lincoln Surveying
APPROVED
Ly the Albemarle County
Commi,inity levelopm.ent Department
_`L.____
7LC 3
H
JU " IN M. SHIIVIP >
1c. 0. 45183
v1ad t ; , 511 °I w�
��s_S'IONAL E�
I I/
4 65Z Cp
�}
'1 iD
q %` L7
Cy7
);I-
\
3� �J
' o
>> n,
O O Q h_
n
rt •
k' n¢•
t
Lu .�
_ o
X$ O
cy
Cz
O
o
Of
Co
.•
La ',.. Q 2
O „a
10' DI-313 I �
"NO PARKING'
SIGN
".
STOP STRIPE
UNDERGROUND -
ELECTRIC LINE
v
UND11WOUND
,.
TELEPHONE LINE
'
STREET SIGN!
�
REVERSE
CURB
�.
6" 22.5• Bends
(Verticoll)
R
C
A..
r•
Bs .
,.
"NO PARKING"
.:
SIGN
UNDERGROUND
TELEVISION
LINE
STACKING BLOC
RETAINING WA
,? '"-- SIGN
BOARD FENCE I
�...�..•__-fit - __�.�.�; __. �.e.....�_...� ...._�....Y.-_
PHONE PEDESTAL
EWER EASEMENT (
' I
• �I I
� o �
o
11,383 SF LOT
2,604 SF HOUSE
C FFE=506.4 C I
0 I
a f,, a
C 4z ry
O y 5 F Y y
A ! S
im
41-
fiT
NEW 20' ACSASIDEWALK WATERLINE '-.�• a y' '` ,:
AS -BUILT
EASEMENT
cJ ;,IWATLDB 4722 PG 416
c3`'.
�j�s' 8' SIDEWALK AND
LANDSCAPING h
EASEMENT
- _-_ DB 4722 PG 417
48" HDPE DETENTION
PIPES X3
Q
11,412 SF LOT
2,696 SF HOUSE
FFE=508.0
{ 'All _N�
- - - — • CCU WASEMI fER
w„
END REVERSE AS -BUILT '.
WIN PVC LNG
CURB TRANSITION TO SIN 5/8' `SIDEWALK
EVERSEETE€
G-6 .:> :. . p
r ' 8' SIDEWALK AND
BEGIN REVERSE
CURB TR%NS01TION LADS APINGF - DB 4722 PG 417
DRAIN
STORMWATER MANAGEMENT FACILITY
ACCESS AND MAINT. EASEMENT
DB 5227 PG 146-154 (EASEMENT PLAT)
C7 ' ACCESS EASEMENT I
I � I
I
11,716 SF LOT I
2,696 SF HOUSE
LL
FFE=504.0
j 11,522 SF LOT
owL;' � I � 2,696 SF HOUSE
FFE=509.3
I
- - - - - - - -
°
K
I
T ELEC,
_. TRANS. I
DOWNSPOUT TO
IMPERVIOUS
DISCONNECTION
(TYP.)
I
/
/
T.V. PIWDES rAL /
PHONE PEDESTAL
ELEC. TRANS %
T,V. PEDESTAL
SCC1 WAS NOT REQUIRED DB 4722 PG 405-419 PLAT
TO BE INSTALLED (
DB 4722 P.420-428 (DECLARATION)
�' 7 8 OPEN SPACE
C10 DEDICATED TO H.O.A.
'Ye27,555 SF
TREE
PRESERVATION
,a EASEMENT
DB 4722 PG 417
PRE-TREATMENT CELL
WAS NOT REQUIRED TO
BE INSTALLED
I 0 PRIVATE STORMS
y d
h r
' y AS -BUILT
SIDEWALK
<a GRATED
GIV\ MANHOLE
COVER
TOP=497.25
0 #57 STONE
1 82.JZ LF 15" HDPE 0 0.86
NEW 15" HDPE STM. SEWER
NTERED ON PROPERTY LINE
' 0' PRIVATE STOR
SEWER AN ,Y STORMWATE
{A MANAGEMENT
ACCESS EASEMENT
{ reDB 4722 PC 41
f, • " 'S
CIV
144
o®
NEW 20' ACSA 104'
SANITARY SEWER
EASEMENT
DB 4722 PG 16
r 531
10t��v
48 DOGHOUSE -
MANHOLE WITH
EXTERNAL DIP DROP
m
TREE
PRESERVATION
EASEMENT
DB 4722 PG 417
It
AS -BUILT NOTES:
U 0
Lo U
� � U
N W
�+ W
Z
d Z
v W
F� W d
q d �
Z
r� F-
D
7
/ N
>
w
N J_
z V)
W
zo
W J
0)0
1. AS -BUILT INFORMATION FROM A FIELD SURVEY BY LINCOLN
SURVEYING, RECEIVED ON 10/19/16, 10/28/16 AND 8/9/18.
2. ALL PROPOSED CONCRETE SIDEWALKS, CURB, AND GUTTER IS
CONSTRUCTED AS OF 9/20/18.
3. LOCATIONS OF STORM SEWERS, SANITARY SEWERS, AND WATERLINE
INFRASTRUCTURE ARE AS SHOWN ON THIS PLAN.
4. SUBDIVISION PLAT REFERENCE: DB 4722 PG 405-419
5. EASEMENT PLAT REFERENCE: DB 5227 PG 146-154
O U JUST M. S IMP >
Li . N . 4s,s 183
VC)
SSE�
0
2-Aw
z
r�
V
R
Q z
LL
z 0
V
d.
J J
T.
m Q
G
a W
J
� Q
Date
04 16 2019
Scale 1 =20
Sheet No.
C2 OF 4
File No.
13.029
7.1'X64 PRETREATMENT CELL
DAM NOT REQI
SOIL REWO
TO 11
INTO PRf
EX.
.iti.l.l�iV.\.l.lf.>•.t.11\IYI 1
STORMTEC MC-4501,
nR En' 1114AI PUT
MT
7.1'X6.9' PRETREATMENT CELL
W/ 57 STONE do FILTER FABRIC �B. " - _ +MRi+
ELEV=496.3 FIE-FER-FABRIg- —,
DETENTION PLAN AND CROSS—SECTION
1 "=5"
X 48 ORIFl
10-YR WSE=493.39 =491,93
1-YR WSE=491.99 V492.99
z� RI ;�
!NV-489.9�L
ORIFICE
:FI:E36raK�• +•�
"1 1
2 INLET 3 DETAIL
C3
PRE—TREATMENT CELL WAS NOT REQUIRED TO BE INSTALLm
6'
ELEV=50235
U
HDPE
INFLOW
MH-1 FLAT TOP
PROFILE VIEW
3' TALL
WEIR PLATE
3' ;r+� , r 15' HDPE
o O.86X
i 5, HBF+E
a-8:58%
TO STM 6
496.17
�_ rI rirr�wmn-
WIRE MESH SCREEN
US
1 O-YR W6E=498.24 V
1-YR WSE=497.17 = F—
tJ' '0 ----
QM 15" HDPE
STM 4 Q 0.3�
L 0
Lo U
Z
N
N W
Z
d z
v W
M� l�.i a
0 0 I �
�z
z
p
D
N
O
Ry N
N
4
Id
I V)
za
wI
N Q
W 2 rn U
64" �.
o
U JU M. SH11\/1P
15" HDPE
0 1.20%
9* HgrE�
6*
STM 5A
ftEY-496..6 496.23
WL H WIRE MESH SCREEN
3"H X 24N ORIFICE
(--3 STR 5 VAULT DETAIL
0 J5183
��ssrorraL ���
0
U
Date
04 16 2019
Scale
1 "=20'
Sheet No.
C3 OF 4
File No.
13.029
510
505
500
495
490
485
480
475
470
(X4) <1) (2) 60 04 (5—>
'101t
C 0)
CC� rCO
0i
4 C
2
)
p n
f,
00
j
;
Cq3
C
C,
Msf
rCd
r
W
C
it
Q
1
11
C4
COQ
L
Ll-
-0
Ld
0
:7,
17"
5
e
Z
7- IL
:C:R
LLI
(-p
LLJ
( n
GRADE
EX. GRADE PROP. GRADE
C" :Z
CD- I
00
PROPT.-CME-1
----10-YR
A
1-YK W*=49/. 3FE=118.31
iL
SEPARA'nON
is" 1 1pb
2.3' MIN.
—7-7
15" HDPE 0 0.86%1
COVER
9.62%
r 4 C .self -
EX. GRADE
r6
PE
EOO.;32]
4r ^41 r-
rnkl ronr
CONCREV—
FILL
--.I Aw
.. .... ...... .......... . 15 HDPE
6
105.92%11
vi 0 8- 61 7*06
C � � C)
CV
Lin
L
C
00 K)
C 1* r -
L )
-5 64 C �1
L
Li
r LO
L� Lei
to u
oo ui
C1 C; cy; Lf) C
A I rd--
0
:> >.
m:Z
L
in%
zaz
mW:2t
f
11+00
STORM SEWER PROFILE X4-7.
Scale: I"=20' Horizontal, 1"=10' Vertical
12+00
13+00
3 3A
ifu
505
500
495
490
485
480
i
PROP.
N
10+00 10-1-50
STORM SEWER
r-2�PROFILE 3-3A
C4 Scale: 1"=20' Horiz., I"=10' Vert.
515
OM'
-
—
tn2l
C:S C-i
CCCO
C 4 C
C 3 C
i
0i CCI)3
04 W
3' C 11
510w
+ Lo
)--
510
o
roctn
505
505
EX.
GRADE —J
500
P
EGRAD
500
495
C;l 49 ft
C6
C11)
C
490
5.83LF
:>
n HDPE
485
485
10-1-00
STORM SEWER
K 3�PROFILE
5-5A
Scale: 1"=20' Horiz., I"=10' Vert.
510
505
500
495
490
485
480
475
470
0
0 0
U JUSTT M.
SHIMP >
Li 4�3
18
lmy�
S-10,NAL