20071212 Ver 1_Mitigation Reports_20070726

Restoration & Conservation
July 26, 2007
North Carolina Department of Environment
And Natural Resources
Division of Water Quality
401 Oversight and Express Review Program
1650 Mail Service Center
Raleigh, NC 27699-1650
ATTENTION: Eric Kulz, Stream Mitigation Specialist
RE: Brown Marsh Swamp Stream and Wetland Mitigation Site -Full Delivery
Project; Response to Review Comments dated July 24, 2007; DWQ #07-1212
The following are responses to questions posed by DWQ regarding the proposed Brown
Marsh Swamp Stream and Wetland Restoration Project.
Valley Slope:
Two answers are warranted for the questions about valley slope. First, existing valley slope
calculations are based on existing conditions surveys. Existing conditions surveys are
conducted on reaches (typically 20 to 30 bankfull widths in length) of project streams, not
the entire project stream length. Therefore, existing conditions surveys give a "snapshot" of
atypical section of a stream's condition on a site. Although these data are accurate for the
reach, there are certain factors that may be misleading if compared to the entire stream
length at a site. In this case, the existing conditions section of the Southern UT displayed a
slope of 0.0003 ft/ft, whereas the designed valley slope was much steeper (0.0080 ft/ft).
The reason for the difference is that the design valley slope takes into account the upstream
most point of stream bed invert elevation and the downstream most point of stream bed
invert elevation. Existing conditions display small drops/steps in the invert elevation of the
channel throughout the entire Southern UT in the project, and were not located within the
existing conditions surveyed bounds.
The second answer deals more with the Northern UT's design. Again, valley slope of the
Northern UT was calculated from a reach of stream during existing conditions surveys.
Also, the invert elevation of the Northern UT was raised almost 1.5 feet at the upstream
(beginning) most point of the project when compared to existing conditions. By raising the
invert elevation you also increase valley slope in order to accommodate the target invert
elevation at the receiving channel. So, even if the existing conditions survey displayed a
valley slope that was the same throughout the entire Northern UT, the valley
Pilot Mill • 1101 Haynes St.. Suite 107 • Raleigh. NC 27604 • www.restorationsvstems.com • Phone [phone] • Fax [phone]

Page 2
July 26, 2007
Eric Kulz, NCDWQ
slope would still have been increased because we are raising its invert elevation at its
upstream most point.
Discharge
The discrepancy is from a rounding difference in the spreadsheet. The discrepancy has been
modified and is displayed as such in the attached morphological table.
If you have any questions or need additional information, please do not hesitate to contact us
at Restoration Systems at 919.755.9490 jrandy(u~restorationsystems.coml or Ko & Associates
at 919.851.6066 jrsmith(c~koassociates.com~ Thanks for your time and considerations.
Sincerely,
M. Randall Turner
Cc: Cyndi Karoly, NCDWQ
Ryan Smith, Ko & Associates, P.C.
Kevin Williams, Ko & Associates, P.C.
Attachment
2 of 2

vl
c~ ~
~;
~i t
4 n, ; ,
d
N
C
~ O
L ~_
Q~ ~l4
L
+~+ O
N
~
3
N I.V C
O
~
~
~
VI
O
~ ~
~
N-~-
~
~
~-
CO
T
p
N ~
(~ ~ 0
U ~
L ~
' ~ ~ ~ ~ ~ ~ p
CO ~ p ~ T 1 ~ ~ ~ T
N p
00 ~
N T
T ~ ~
p ~ Q
~ p
O d'
'
~ ~ W U ~ f~
O O ~ O ~ r 00 N ~ O O O p O T O O O O T N r r 0 ~
N~
'i cOp (n p ~
.- N
N p r N r N O O O ~ N
~ ~ ~

O ~
T
t
//t
L.L T
~
^
i
U ~
~
~
a U
V ~ Z ~
•°
c ~
Cn

7 U O Lf) , Cp .- r O (O O ~ `~ C`') O O O I~ O O O ('7 C7 O O V O CO O ~ p
S i 0
V ~ (n W U
Q Lf) O
O O C7 r ~ N
r '"'
N r O C'7 Ln
O r
T O a0
T X
r 0
0 0
0 0
0 O ~
O r 01
~ QO
O
I~
~
0~ O ~
O ~
~ O ~ ~ r ~ O O O ~ ~
N
~ 3
Y Q
O
~
w
r
~ `N
O O J ~
J T
/
~¢
W

cts ~ ~ ~ W W J ~
~ ~
~~ ^ CJ .~ a Q ~ j j Q Q

'
~ x
~ W
w
~
~ J
w C`3
m f-
m ~
Q ~
Q ~
~ ~
I-
~ F-'
Q _
~ W
p
.~ H
a. f-
^ U
Q d

W ~ Q ~ W Q U ~ ~ Z U'
Z O
H H O H
^ LLI ~ ~ J
O ~ J~
O $ J
O J J~
O~
w
~ m
Q ~
~ W
~ = ~
x w
~ _~
^ Q
~ d w
= ~ ~ ^
~ F-
~ ~
2 ~ Y O O w
^ w
o ~ ~ O
O ~~
~ W ~
w J J J o
O U CC L
L O LL ~ CC F}- ~ cn
W m
O w
LL O a.
l.L J ~ L.L ~ LL J
O ~ Q J
> J
> ^ J
> > > ^ ~- z 0 .
O ~ O ~ o ~ >. C7 ~ O p O ^ ~ O ~ O ^
F- Q z W
Y W
Y = tL
Y ~
Y W
Y W
Y = w
~ z 0 ^ O ~ z O W Q
~ J OW
d w Ou'
Y J O=
H J OY
~ Q
U W
CC Q z z ~
^ z z z z ~
^ ~- Q ~ _
^ ~ J Q
w m
? J
J w 0 F-p x
Q ~z 0
O ~^
Q- O
O I-z
QQ
w 0 ~ ¢ Q Q _ Q Q Q Q _ z w Q Q Q w ~ Q > O QJ
CC ~ QQ
OC m ~ 0[ ~ m w m
~ J cn ^ m m ~ m m m m ~ w ~ oC OC DC m cn > a ~ cn