HomeMy WebLinkAboutSDP202000017 Correspondence 2020-02-25 (5)SHIMP ENGINEERING, P.C.
Design Focused Engineering
February 18t", 2020
Stephen C. Brich, P.E.
Commonwealth of Virginia
Department of Transportation (VDOT)
1601 Orange Road, North Wing
Culpeper, Virginia 22703
RE: Response Letter #1 for SDP-2019-037 2511 Avinity Drive
Dear Stephen,
Thank you for your review of the Initial Site plan request for 2511 Avinity Drive. This letter contains
responses to County comments dated July 10' 2019. These comments were received with the approval of
the Initial Site Plan for 2511 Avinity Drive dated December 2nd 2019. Our responses are being submitted
simultaneously with the submission of the Final Site plan and are as follows:
Per our previous comment on the rezoning application, it is unclear if the existing right lane will
be sufficient for the proposed increase in use. Please provide this analysis.
Noted, if VDOT requests a more formal analysis we can provide.
Here is a quick analysis:
24 new apartment units will generate an additional 14 AM peak hour trips and 17 PM peak
hour trips (ITE 220). The total Avinity subdivision has a future total of 209 townhome units
which generates 64 AM peak hour trips and 80 PM peak hour trips. (ITE 221)
Peak right turns vs traffic occurs in the AM (heading into Charlottesville)
Total AM trips for Avinity Entrance: 78
Total AM right turns: k * AM trips = .6952*78 = 54
Total opposing trips on Avon St Ext: k*d*Avon St AADT = .6952*.1087*11000 = 831
Using the Figure 3-26, Warrants for Right Turn Treatment on page 81, VDOT Appendix F,
this lands the condition in the "Taper Required" zone.
00
0
x
w
a 80
N
w
J
U_
S
w
> 60
N
Z
Q
F
r
40
x
a
20
PHV APPROACH TOTAL, VEHICLES PER HOUR
A right turn/taper lane already exists. Thus, no revisions to the existing lane is required.
912 E. High St. Charlottesville, VA 22902 1434.227.5140 1 shimp-engineering.com
2. Provide analysis demonstrating that the existing storm structure being tied in to with the Avon
Street ROW remain adequate in the post -development condition.
See attached LD-204 and LD-229.
If you have any questions or concerns about these revisions, please feel free to contact me at
stephanie@shimp-en in�g com or by phone at 434-227-5140.
Regards,
Stephanie Paul
Site Designer.
Shimp Engineering, P.C.
912 E. High St. Charlottesville, VA 22902 1434.227.5140 1 shimp-engineering.com
2511 AVINITY DR
LD-204 Stormwater Inlet Computations
Inlets on Grade Only
Sag Inlets Only
9
a
U
Z
N
C
N
Q
C
O
C
E
>
Z
fA
Y
N
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O
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U
C
Q
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U
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H
O
E
t
y
y
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i
m
c
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X
X
a
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t
cd
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CD
N
Q
c
O
=
c
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J
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tC
C
J
Q
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N
U
U
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C
fC
N
O
>
(C
O
N
O d
O.
N
W
C
>'
CO
O.
-O
2
O-
-O
cn
5
U
U
c[
U
C3
C7
C7
c[
o-
c7
H U
o
o
Ct
U
U
o
1
2
3
4
5
6
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
(ft)
(ac)
(in/hr)
(cfs)
(cfs)
(cfs)
('/')
('/')
(,/,)
(ft)
(ft)
(cfs)
(cfs)
(ft)
(ft)
(ft)
C2
131-313
10
0.24
0.71
0.17
4.0
0.69
0.00
0.69
0.015
0.042
0.020
0.08
0.5
0.16
4.68
6.5
1.12
0.00
1.12
0.11
0.5
0.22
5.60
B2
131-36
10
0.45
0.71
0.32
4.0
1.27
0.00
1.27
0.015
0.015
0.020
0.12
0.5
0.24
5.91
6.5
2.06
0.00
2.06
0.16
0.5
0.33
8.15
X1 PRE
131-36
12
0.42
0.32
0.13
4.0
0.54
0.00
0.54
6.5
0.87
0.00
0.87
X1 POST
DI-3C
12
0.14
0.41
0.06
4.0
0.22
0.00
0.22
6.5
0.36
0.00
0.36
X2 PRE
DI-36
8
0.33
0.34
0.11
4.0
0.45
0.00
0.45
6.5
0.73
0.00
0.73
X2 POST
DI-36
8
0.24
0.38
0.09
4.0
0.37
0.00
0.37
6.5
0.60
0.00
0.60
X3 PRE
DI-36
6
0.13
0.53
0.07
4.0
0.27
0.00
0.27
6.5
0.43
0.00
0.43
X3 POST
DI-3C
6
0.12
0.41
0.05
4.0
0.20
0.00
0.20
6.5
0.33
0.00
0.33
X4 PRE
DI-3B
6
0.51
0.36
0.18
4.0
0.74
0.00
0.74
6.5
1.19
0.00
1.19
X4 POST
13I-36
6
0.17
0.49
0.08
4.0
0.34
0.00
0.34
6.5
0.55
0.00
0.55
Note: For existing inlets (X1-X4), postdev runoff to the inlet is less than predev. No further analysis needed for these inlets or pipes.
LD-229 Storm Drain Design Computations
2511 AVINITY DR
From
To
Catch.
Runoff
Increment
Accum.
Total
Total
Total
Up
Down
Pipe
Invert
Pipe
Pipe
Velocity
Flow time
Structure
Structure
Area
Coef
AC
AC
TOC
Intensity
Flow
Invert
Invert
Length
Slope
Diameter
Capacity
Increment
ac
min
in/hr
cfs
Elev.
Elev.
(ft)
%
in
cfs
(ft/s)
min
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
C2
C1
0.24
0.71
0.17
0.17
5.00
6.81
1.17 532.00
530.00
132.60
1.51 %
15
8.6
4.9
0.45
B2
B1
0.45
0.71
0.32
0.32
5.00
6.81
2.16 532.40
532.00
18.07
2.21 %
15
10.4
6.7
0.04
A2*
Al
0.55 529.00
525.94
107.81
2.84%
15
15.7
4.9
0.37
*10 yr Flow from H droCAD model