20100099 Ver 2_Mitigation Information_20121213

Axiom Environmental
218 Snow Avenue
Raleigh, North Carolina 27603
MEMORANDUM
TO Pancho Mitigation Bank IRT
FROM Axiom Environmental, Inc
DATE December 13, 2012
RE Pancho Mitigation Site NC SAM Effort 10 -010
The goal of this effort is to make a case, using the current draft version of the N C Stream
Assessment Method (NC SAM), that stream functions will be unproved through the implementation
of Enhancement Level 1 efforts in Kennedy Mill Branch and the Main Tributary to Kennedy Mill
Branch (hereafter referred to as the Main Tributary) at the Pancho Mitigation Site in Wayne County
Although NC SAM has been designed for use on existing conditions, we have used the functional
framework provided by NC SAM to anticipate changes that can reasonably be anticipated to occur as
a result of proposed enhancement activities We used NC SAM draft version 4 (dated July 20, 2012)
for this effort
Axiom staff members visited the site on December 7, 2012 and walked the two subject streams
During this walk, it was determined that a single NC SAM Field Assessment Form will suffice to
document the current function of the two streams The specific site where this form was completed is
approximately 400 feet upstream of the upper end of proposed Priority 1 stream restoration on
Kennedy Mill Branch (designated as site number "KMO" on the field assessment form and in Figure
B)
The proposed Enhancement Level 1 activities include raising the stream bed for approximately 1334
linear feet in Kennedy Mill Branch and 852 linear feet in the Main Tributary (Figure B) and the
removal of non - native, mvasive species (specifically Chinese privet [Ligustrum smense]) within the
project boundaries adjacent to these streams The implementation of these activities is anticipated to
result in positive changes to five NC SAM metrics Metric (M) 4 (Feature Longitudinal Profile), M5
(Signs of Active Instability), M6 (Streamside Area Interaction), M15 (Wetland Presence), and M24
(Vegetative Composition) Based on this information, Axiom divided Kennedy Mill Branch into three
reaches (KM 1, KM2, and KM3) and the Main Tributary into two reaches (MT1 and MT2), each
anticipated to receive different metric ratings resulting from the proposed enhancement activities
The locations of these reaches are depicted on Figure B
The results of this analysis is, in current condition, the subject reaches of Kennedy Mill Branch and
the Main Tributary receive an overall NC SAM rating of Medium (Hydrology = Low, Water Quality
=Medium, and Habitat= High) The proposed enhancement activities are anticipated to result in all
five reaches receiving an overall NC SAM rating of High, with all primary functions receiving ratings

of High, with two exceptions being the upper reaches of each stream, which are anticipated to receive
Hydrology ratings of Medium due to the contmued incised state of the stream channel in these areas
Table 1 displays the descriptors selected to represent current conditions for the five metrics and the
anticipated future descriptors for these metrics following implementation of enhancement activities
Reasoning for the selection of descriptors follows
M4 (Feature Longitudinal Profile) — It is anticipated that raising the streambed as proposed in the
Figure B cross - sections will improve the longitudinal profile in the lower half ofthese sand -bed
stream reaches so they will no longer be considered "substantially" altered
M5 (Signs of Active Instability) — It is anticipated that the raising of the streambed and flattening of
streambed slope will reduce energy on stream banks, resulting in stabilization of the stream bed
and banks in the entire length of the streams subject to enhancement
M6 ( Streamside Area Interaction) — It is anticipated that raising the streambed will restore
reference interaction within the lower third of both streams (KM 1 and MT 1), improve
streamside area interaction to a moderate level in the middle reach of Kennedy Mill Branch
(KM2), and have no effect on the current rating of the upper reach of each stream (KM3 and
MT2)
M 15 (Wetland Presence) — The extent of wetlands in the streamside area following enhancement
activities has been determined based on the degree of incision of the channel ofthe two streams
The areas anticipated to be restored to jurisdictional wetlands are currently underlain by hydric
soils and support a primarily hydrophytic vegetation community Raising the stream bed, and
the resulting elevation of groundwater levels in the adjacent floodplam, is anticipated to result in
the restoration of streamside area wetlands in the lower third of Kennedy Mill Branch and the
lower half of the Main Tributary
M24 (Vegetative Composition) — The existing condition selection of descriptor B is primarily a
result of the existence of extensive stands of Chinese privet within the streamside area The
removal of privet is anticipated to result in the future selection of descriptor A for the
streamside area of both streams
The five NC SAM metrics anticipated to be affected by proposed enhancement activities are used to
generate ratings for all three primary stream functions Hydrology, Water Quality, and Habitat
Table 2 displays the current condition ratings for the function classes affected by the five metrics and
the anticipated future ratings for these functions following implementation of enhancement activities
A description of how these metrics are used in the determination of stream functions and the effects
of the anticipated change in ratings resulting from proposed enhancement activities follows
M4 (Feature Longitudinal Profile) is used by the Hydrology Class 4 function Stream
Geomorphology and the Habitat Class 3 function Stream Stability Proposed enhancement
activities are anticipated to elevate the current rating of Stream Geomorphology from Medium
to High for the lower two reaches of Kennedy Mill Branch (KM 1 and KM2) and the lower

reach of the Main Tributary (MT 1) and not change the rating of the upper reaches of the
streams (KM3 and MT2) Proposed enhancement activities are anticipated to elevate the
current rating of Stream Stability from Low to High for the lower two reaches of Kennedy Mill
Branch (KM 1 and KM2) and the lower reach of the Main Tributary (MT 1) and elevate the
current rating from Low to Medium for the upper reaches of the streams (KM3 and MT2)
M5 (Signs of Active Instability) is used by the Hydrology Class 4 function Channel Stability, the
Water Quality Class 2 function Indicators of Stressors, and the Habitat Class 3 function Stream
Stability Proposed enhancement activities are anticipated to elevate the current rating of
Channel Stability from Low to High for all five reaches considered Proposed enhancement
activities are anticipated to eliminate NC SAM Water Quality stressors, elevating the current
rating of the Water Quality primary function from Medium to High for all five reaches
considered Proposed enhancement activities are anticipated to elevate the current rating of
Stream Stability from Low to High for the lower two reaches of Kennedy Mill Branch (KM 1
and KM2) and the lower reach of the Main Tributary (NIT I) and elevate the current rating from
Low to Medium for the upper reaches of the streams (KM3 and MT2)
M6 (Streamside Area Interaction) is used by the Hydrology Class 4 function Floodplain Access and
the Habitat Class 3 function Streamside Habitat Proposed enhancement activities are
anticipated to elevate the current rating of Floodpla►n Access from Low to High for the lower
reach of Kennedy Mill Branch (KM1) and the Main Tributary (MT 1), from Low to Medium for
the middle reach of Kennedy Mill Branch (KM2), and not change the rating of the upper reach
on each stream (KM3 and MT2)
M 15 ( Wetland Presence) is used by the Baseflow sub - function of all primary stream functions as
well as Water Quality Class 3 function Upland Pollutant Filtration For these functions, wetland
presence is a value -added metric that increases a rating that is not already optimal In the case
of these streams, Baseflow and Upland Pollutant Filtration are optimal in the current condition,
therefore, a change in the status of streamside area wetlands has no effect on the NC SAM
ratings
M24 (Vegetative Composition) is used by the Habitat Class 3 function Streamside Habitat
Proposed enhancement activities are anticipated to elevate the current rating of Streamside
Habitat from Medium to High for the lower two reaches of Kennedy Mill Branch (KM 1 and
KM2) and the lower reach of the Main Tributary (MT I) and not change the rating of the upper
reaches of the streams (KM3 and MT2)

Table 1 The NC SAM metrics affected by proposed stream enhancement activities, their current condition descriptors, and
anticipated future descriptors following mitigation implementation The initials "KM" refer to locations of reaches on
Kennedy Mill Branch, and the initials "MT" refer to locations or reaches on the Main Tributary to Kennedy Mill Branch The
locations of stream reaches (KMO, KM1, etc ) are provided in Figure B
Current
Condition
Post Restoration
Estimated
Descriptors
NC SAM Metrics Affected by Mitigation
Descriptors
KMO
KM1
KM2
KM3
MT1
MT2
M4 - Feature Longitudinal Profile
A
B
B
A
B
A
M5 - Signs of Active Instability
C
A
A
A
A
A
M6 - Streamside Area Interaction
CC
AA
BB
CC
AA
CC
M15 - Wetland Presence
NN
YY
NN
NN
YY
NN
M24 - Vegetative Composition
BB
AA
AA
AA
AA
AA

Table 2 The NC SAM functions affected by proposed stream enhancement activities, their current condition ratings, and anticipated
future ratings following mitigation implementation The initials "KM" refer to locations of reaches on Kennedy Mill Branch,
and the initials "MT" refer to locations or reaches on the Main Tributary to Kennedy Mill Branch The locations of stream
reaches (KMO, KM1, etc ) are provided in Figure B Gray highlighting indicates ratings anticipated to be improved by
proposed enhancement activities
NC SAM Functions Affected by Mitigation
(in bold)
Hydrology (1)
Baseflow (2)
Flood Flow (2)
Streamside Area Attenuation (3)
Floodplain Access (4)
Wooded Riparian Buffer (4)
Microtopography (4)
Stream Stability (3)
Channel Stability (4)
Sediment Transport (4)
Stream Geomorphology (4)
Water Quality (1)
Indicators of Stressors (2)
Current
High
High
High
High
High
Condition
In- stream Habitat (2)
Post Restoration
Estimated
Ratings
High
Ratings
High
Stream Stability (3)
Low
High
High
KMO
KM1
KM2
KM3
MT1
MT2
Low
High
High
Medium , _
-High
Medium
High
High __
High
-- -- -- -
High
High
High_
dMe
Low
High
High
_ :Mediu_m�N__
High
-di um
Low
High -
High
, Low
tHigh'
Low
Low
I High
g
Medium
Low `
�
e High
Low
High
High
High
High
High
High
High
High
High
High
High
High
Medium
High
High
High
High
High
Low
High
High
High
High
High
High
High
High
High
High
High
Medium
High
High
Medium
High
Medium
Medium High High High - ---High--- High
Yes No No No No No
Habitat (1)
High
High
High
High
High
High
In- stream Habitat (2)
High
_ High
High
High
High
High
Stream Stability (3)
Low
High
High
Medium
High _
Medium r '
Streamside Habitat (2)
High
High
High
High
High
High
Streamside Habitat (3)
Medium
High
High
Medium
_
i = x High
Medium
OVERALL
Medium
High
High
_ ° High"
x
High,
High

Easement Boundary
Major Contour
Minor Contour
Priority 1 Stream Restoration - 5,322 It
Stream Enhancement Level 1 - 1969 It
-'� Abandoned Channel and Ditch Backfill
Log Vane
Cross Vane
Kennedy Mill Br
Start Restoration
Sta 00 +00
End Enhancement Level 1
Elev 91.31
Kennedy Mill
Reach 1 (KM1)
Kennedy Mill
Reach 2 (KM2)
Kennedy Mill
Reach 3 (KM3)
Start Enhancement Level 1
Sta 13 +34
Elevation at grade
'o.
o
1
J
Location of
Data Fonn
KM 0
l
QE1ev ributa
estoraion
\ +00
\ \\ hancement Level 1
0.5
loS
Main Tributary
/ Reach 1 (MT 1)
_Ilo•.
Start
Enhancement Level 1
Ste 08 +52
Elevation at grade
Alan FrlkMomlenW. no.
Main Tributary
Reach 2 (MT 2)
Main THlb itary
90
-_ 96
Y 9/
e 92
% 90
Y
"' 88
86
0 100 100 300 400 500 600 ]00 B00 900
xrtbn(laatl
raMne Channel Bed tpraposed Channel Bed tTOp Bank
KMM1 — KM2 — KMM3 —
Kennedy Mill Branch
96
C� 92
9 90
BB
86
0 200 400 600 900 low 1200 1400
ilatbn (hal)
—*—Erlsdn9Channe1 Bed -4*- proposed Channel Bed -0 -TOp Bank
Note: Pools are not depicted in profile due to scale. Pool locations
will be determined In the field during construction.
NOTES/REVISIONS
Project:
Pancho
Mitigation Bank
Wayne County
North Carolina
Title:
NC SAM
Evaluations
1 In = 200 ft FIGURE NO.
Date: B
Deoember2010
ii O No.:
10-010