20100549 Ver 1_More Info Received_20101103

FW: Davis Village DWQ 10-0549
FW: Davis Village DWQ 10-0549
Lucas, Annette
Sent: Wednesday, November 03, 2010 11:47 AM
To: Strickland, Bev
Attachments: Sheet 5-Drainge Plan 110310.PDF (2 MB) ; Plunge Pool Spreadsheet.pdf (17 KB)
Hi Bev,
Can you please print a copy of Sheet 5-Drainage Plan for me on the large printer?
Thanks,
Annette
From: Jesneck, Ken [maiIto: [e-mail]]
Sent: Wednesday, November 03, 2010 9:11 AM
To: Lucas, Annette
Cc: 'John Dempsey'; '[e-mail]'; [e-mail]
Subject: Davis Village DWQ 10-0549
Page 1 of 2
Annette,
As we discussed yesterday, please find attached the Storm Drainage Plan and supporting calcs for the scour hole
plunge pool.
The storm pipe in question is from FES 34 to FES 35 under Kingston Grove Drive near its intersection with
Morrisville Parkway. The drainage area for this line is the open space between the right of way of Morrisville
Parkway and the rear drainage of the townhomes in Davis Village. The drainage area for FES34 is 0.82 acres,
which will result in a 10-year peak storm flow of 2.0 cfs.
The Town of Cary required that all stormwater from impervious surfaces must be directed to the wet detention
pond, which we have accomplished with this design. Initially, I had FES 34 connected to the junction box serving
the storm drainage system of Morrisville Parkway and then ultimately being discharged through the performed
scour hole as shown on the plans. The design was approved by the Town of Cary Devfelopment Review
Committee, but upon approval be the Town of Cary Engineering Department, the amount of flow from FES34 into
the Town of Cary system would be in excess of the maximum flow allowed for a plunge pool for the pipe diameter,
which I believe is 10 cfs.
Upon learning of this situation, we met with the Town of Cary to explore options. We discussed several, but two
options seemed the most practical. Option 1 was to skew the pipe to its own scour as shown on this design.
Option 2 was to extend Y133 to the location of FES 34 and capture all the stormwater and pass it through the
BMP. Option 2 was selected for several reasons, one being to avoid having to revised the permit will another
point source and the other being the Town of Cary thought this a better choice, even though this Option included
the removal of trees and vegetation for grading. The invert of YI33 is at a higher elevation that FES 34, and
would require grading to direct the stormwater flow into the inlet structure. The Town of Cary did approved
Option 2.
Ultimately, when the clearing and grading of the area was nearing completion, the developer (Pulte Homes) did
not want to remove the trees that were necessary to cosntruction Option 2. So now, we are back at Option 1. 1
have updated Sheet 5-Storm Drainage Plan to include the new pipe location and the scour hour plunge pool
configuration.
Let me know if this is acceptable approach. Thank you for your assistance.
Ken Jesneck, PE, LEED AP
https://mail.nc. gov/owa/?ae=Item&t=IPM.Note&id=RgAAAAAAOgPoLNIPQZ06vHVR... 11/3/2010
FW: Davis Village DWQ 10-0549
WITHERB `?C RAVEWEL
111 MacKenan Drive I Cary, NC 27511
Phone: [phone] Fax: [phone]
Direct: 919.535.5139 1 Mobile: [phone]
[e-mail]
www.withersravenel.com
NOTICE OF CONFIDENTIALITY AND NONDISCLOSURE: This electronic message. which includes any attachments and other
documents referred to herein, contains information from Withers & Ravenel, Inc. that may be proprietary or confidential. The
information is intended for the use of the addressee(s) only, If you are not the addressee, note that any disclosure, copying,
printing, distribution, or use of the contents of this message is prohibited If you received this message in error, please advise the
sender by reply and delete this electronic message and any attachments.
COPYRIGHT NOTICE: Copyright 2010 Withers & Ravenel, Inc. All Rights Reserved by Withers & Ravenel, Inc. This electronic
message, any attachments thereto and all documents referred to therein are provided for the recipients information only, and no
rights are licensed, transferred or otherwise granted by the transmission of this electronic message by Withers & Ravenel, Inc. or
receipt of this message by the recipient or any other party.
Page 2 of 2
https://mail.nc. gov/owa/?ae=Item&t=IPM.Note&id=RgAAAAAAOgPoLNIPQZ06vHVR... 11/3/2010
:F? ?. ?? "?•? may"` _ ? ,? ?.??.s ?„4 F ?? _
1 5 • _ t ? 1', -fir- ? r? -?? ?`-^•_?'
r t t r- j
f LC
41
r 7`..? ' ?r',•"\ I ? r n. u' ("T,°^--..yam,,..-.._.,,,_ ? ?3 ,f jf # t .f j ?--_•?, ??.i L ? r---- ? ? 1 ? ?' _. t r ?- -` ?g_
r
1 L 1l " a /
00
f
r
ti a
zzz,
XN
JR*
x % a1?
[` d Y' pi J`/ r
Z.
t
A d?a t
A r f
I r? 1 -
s9 ? ?`"",+`4'. _"°yw,.?°''fj ??•'f?l r /t r s `-?"`-.?..._..? 3.*a, -. ?.. -?J Y
RIPRAP LINED PLUNGE POOL FOR CANTILEVER OUTLET (Version 8.99)
(Reference Design Note No. 6 (Second Edition), Jan. 23, 1986
-------------------------------------------------------------------------------------------------------------
-------------------
-------------------
-----------------
JOB: Davis Village Subdivision
DESIGNER: KLJ Date: 11/3/2010
CHECKER:
------------------------------------------------------------------------------------------------------------- Date:
-------------------
-------------------
----------------
INPUT DATA:
Conduit Diameter D= 1.25 ft
Conduit Discharge: Q= 2.10 cfs
Conduit Slope at Outlet: S= 0.05 ft/ft
Conduit Outlet Invert Elevation: El, CO = 315.50 ft
Tailwater Elevation: El, TW = 315.50 ft
Outlet Channel Invert Elevation:
------------------------------------------------------ El, CH =
------------------- 315.50
------------------- ft
-----------------
-------------------------------------------------------
Water Density: RHO = 1.00
Bed/Riprap Particle Density: (Default 2.64) RHOS = 2.64
D, 50 Riprap Size: RS = 0.16 ft
Riprap Thickness: (2.5*D, 50 recommended) RT = 0.40 ft
Bedding Thickness: (6 inch min. rec.) (Enter 0 for geotextile) BT = 0.00 ft
Side Slope Ratio: Zw = 2.00 ft/ft
Upstream End Slope Ratio: Zlu = 3.00 ft/ft
Downstream End Slope Ratio: Zld = 3.00 ft/ft
Combined End Slope Ratio:
------------------------------------------------------------------------------------------------------------- Z1 =
------------------- 3.00
------------------- ft/ft
-----------------
OUTPUT---POOL LOCATION AND DIMENSIONS:
Vert. Dist. from Tailwater to Conduit Invert:
Submergence Check: (If Zp < 0, Use Zp = 0)
Beaching Check: [Q/(gD"5)^0.5 <_ (1.0+25*D,50/D)]
*"Beaching Controlled**
Distance from Conduit Exit to C/L Pool:
Pool depth at C/L Below Conduit Invert:
Pool Bottom Elev:
Pool Bottom Length:
Pool Bottom Width:
Upstream Pool Length at Tailwater Elev.:
Downstream Pool Length at Tailwater Elev.:
Pool Width at Tailwater Elev.:
Check Side Slope Ratio: (Wr>=We)
""Side Slope Ratio Zw O.K.**
Check Min. End Slope Ratio: (Lru & Lrd >= Le)
**End Slope Ratios O.K.**
Check Upstream Length: (Lru >= Xm)
**End Slope Ratio Zlu O.K.**
Pool Bottom Elev. at Bottom of Riprap:
Pool Bottom Elev. at Bottom of Bedding:
OUTPUT---VOLUMES BELOW WATER SURFACE ELEVATION:
Volume of Excavation (measured from bottom
surface of bedding):
Volume of Rock Riprap:
Area of Geotextile:
Zp = 0.00 ft
Use Zp = 0.00 ft
O.K.
Xm = 0.78 ft
Zp+0.8Zm = 1.08 ft
EI,PB = 314.42 ft
2Lr2 = 0.85 ft
2Wr2 = 0.83 ft
Lru = 3.67 ft
Lrd = 3.67 ft
2Wr = 5.15 ft
O.K.
O.K.
O.K.
El, BR = 314.02 ft
El, BB = 314.02 ft
V,pbs = 1.4 cu yd
V,rs = 0.8 cu yd
A,gt = 12.0 sq yd
Spreadsheet developed by D. Hurtz, Midwest NTC, 1/90
Spreadsheet modified by M. Dreischmeier, Eau Claire TC, Wis., 3/98
Design Note No. 6 (Second Edition), Jan. 23, 1986
'Riprap Lined Plunge Pool for Cantilever Outlet'
Natural Resources Conservation Service
Engineering Division

ll'
I

_

t
w
III
c

I
_ i
I

1
1
?
I _ I
' 1
' ? ,.
?
I
h I ?
I ;rt ?
I
? I
? _

I I

I
?_' II ? I

I
t
1 I
I

I
I I ? I I

I

I
I

I
i
I

e
II

I i I
_ J
_
-
I _ _
r ? sr
I
?
? ?I _ _
I 1 III - I
R ¢' -

I I

i f
s

i
y t
? ?? Ti ,Ir I(
y] k I
k

-
- I L

;I d

- - it ? ? ? . _ - - - -
I?

i

?

1
Y - 7
?
I LI
1 ? r J i
?
? ?
g
I
l?
J ? -
I?
r I ?

i
rr
r

., i
l l
I
I
t It

I

I
lj,
f

'.?•.___.. _ .....-.?.m.

?,... ?_.?.?.?.??.,...: .?,??m.....,.... ,._...e......._,_ ....?-.._._.._...?:. .-_._....._....
I
_?.?..-??., .?.:. ?..:?. .?.-,e., ?.a...?..m.-mow -_ --:- ??...

se..?.......,.,? I _

?.-......e.._?._..?..?.