20130595 Ver 1_Addendum_WithCoverLetter_Final_20151130

November 30, 2015

Paul Wiesner
Western Supervisor, Project Management
North Carolina Department of Environmental Quality
Division of Mitigation Services
5 Ravenscroft Dr., #102
Asheville, NC 28801

Subject: Mitigation Plan Addendum for the Upper Silver Creek Restoration Project in Burke
County
Catawba River Basin – CU#03050101-050050
Service Contract No. 003270
DMS No. 94645
Baker Project No. 120598

Dear Mr. Wiesner,

Please find enclosed the revised Mitigation Plan Addendum for the Upper Silver Creek Restoration
Project in Burke County. It is based on field discussions and written comments from DMS, Corps of
Engineers, and NC-DEQ. Included are revised asset tables and maps detailing the reclassi fication of
0.42 WMUs from riparian to non-riparian wetlands.

If you have any questions concerning the Addendum or require any additional information, please feel
free to contact me at 919-481-5731 or via email at [e-mail].

Sincerely,
Scott King, LSS (#1301), PWS (#1908)
Michael Baker Engineering, Inc.
Upper Silver Creek Stream and Wetland Restoration Project – Mitigation Plan Addendum
Michael Baker Engineering respectfully submits this wetland WMU reclassification as an addendum to
the mitigation plan for the Upper Silver Creek Restoration project (DMS Project #94645). The revised
table reclassifies 0.42 WMUs from riparian to non-riparian wetlands.
On October 26, 2015, Baker personnel met on site with representatives from the Corps of Engineers, NC
Division of Water Resources, and NC Division of Mitigation Services to inspect existing wetland
mitigation areas proposed for reclassification from riparian to non-riparian. After discussion, it was
determined that the wetland area located within a seep along a slope in the southwestern portion of
the project was located outside of the geomorphic floodplain and acceptable for reclassification (see
Figure 2). Currently the wetland area is classified as predominantly Riparian Wetland Enhancement
(JDW1A) at a 2:1 credit ratio for 0.21 WMUs, with two pockets of Riparian Wetland Restoration (areas
R1A and R1B) at a 1:1 credit ratio for 0.21 WMUs. This addendum simply reclassifies those WMUs as
Non-Riparian (see Table ES.2.Rev).
During the field investigation Baker also agreed to install an additional monitoring well in the newly
reclassified non-riparian wetland area (see Figure 2). It will be installed in the upper portion of the
wetland enhancement area over the winter 2015 before the growing season begins in 2016 to capture
groundwater data for Monitoring Year 2 onward. The existing monitoring well located in this non-
riparian area was installed in one of the wetland restoration areas. Thus this non-riparian wetland area
will have two groundwater monitoring wells located within it.
Additionally, during the GIS analysis conducted to reclassify and revise the WMUs for the project, two
errors were discovered in the original mitigation plan calculations of the acreage for the R4 and R5
riparian wetland areas proposed for restoration. The acreage for R4 was reported as 0.62 ac but is
actually 0.44 ac, while the acreage for R5 was reported as 1.53 ac but is actually 1.29 ac. These errors
subsequently resulted in the miscalculation of the total WMUs for the project, with a mistaken reported
overage of 0.41 WMUs. The corrected WMU values are reflected in the revised asset Table ES.2.Rev.

Table ES.2: The original wetland mitigation plan asset table (from approved the mitigation plan,
dated October 2013):
Table ES.2 Upper Silver Creek Mitigation Plan Overview (Wetlands)
Upper Silver Creek Mitigation Plan-EEP Project #94645
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Comments
ENHANCEMENT WETLANDS
Jurisdictional Wetland 1 (JDW1a) - Riparian
Enhancement
(2:1) 0.53 0.53 2:1 0.26
Existing jurisdictional wetland; 2:1 enhancement proposed to include minor
grading in areas of fill and altered drainage patterns, replanting of mowed
vegetation to include woody bottomland wetland species. Some peripheral
benefit from hydrology enhancements to tributary (UT3) and mainstem.
Jurisdictional Wetland 1 (JDW1b) – Riparian
Enhancement
(2:1) 0.9 0.9 2:1 0.45
Existing jurisdictional wetland; enhancement proposed at 2:1 to include
significant enhancements to hydrology and vegetation. UT3 will be raised to
bring hydrology within 1’ of the surface and will be routed along the
periphery of this wetland. In addition, hydrology from the mainstem will be
augmented (base flow elevation raised by 0.5’) and will be routed closer to
the wetland area. Mowed vegetation will be planted with woody bottomland
wetland species.
Jurisdictional Wetland 2 (JDW2) –Riparian
Enhancement
(2:1) 0.51 0.51 2:1 0.25
Existing jurisdictional wetland; enhancement proposed at 2:1 (typical
enhancement ratio) to include plug of existing drainage ditch which has
altered wetland hydrology, planting of woody bottomland wetland species to
replace mowed grasses, minor grading of lower part of wetland and increase
of baseflow elevation of mainstem by approximately 1.5 feet.
Jurisdictional Wetland 3 (JDW3) – Riparian
Enhancement
(2:1) 0.03 0.03 2:1 0.02
Existing jurisdictional wetland; enhancement proposed at 2:1 to include
minor grading to remove less than 12” of overburden, reduction of hydraulic
gradient by plugging existing drainage ditch and raising baseflow elevation
of mainstem (these will serve to decrease the gradient of groundwater flow
within the project area, resulting in an increased hydroperiod for adjacent
wetlands). The area will be planted with woody wetland species to replace
mowed grasses.
Jurisdictional Wetland 4 (JDW4) – Riparian
Enhancement
(2:1) 0.24 0.24 2:1 0.12
Existing jurisdictional wetland; enhancement proposed at 2:1 to include
reduction of hydraulic gradient to adjacent areas by plugging existing
drainage ditch and raising baseflow elevation of mainstem. The mainstem
will also be relocated which should increase the influence of its hydrology on
adjacent areas and decrease the gradient of groundwater flow. The area will
be planted with woody wetland species to replace mowed grasses.
Jurisdictional Wetland 5 (JDW5) – Riparian
Enhancement
(2:1) 0.81 0.81 2:1 0.40 Existing jurisdictional wetland; enhancement proposed at 2:1 to include
removal of overburden (fill) from areas where vegetation reflects the altered
soil conditions, plugging/removal of ditching in the immediate vicinity and
also upstream along the long linear ditch that parallels the stream,
enhancement of wetland hydrology as a result of Priority I stream restoration
and an increased base flow elevation, and increased storage/runoff retention
by disconnecting direct ditch connections to the main channel and increasing
ponding and recharge.
Jurisdictional Wetland 6 (JDW6) – Riparian
Enhancement
(2:1) 0.30 0.25 2:1 0.13
Existing jurisdictional wetland; enhancement proposed at 2:1 to include
diversion of additional overland flow into the area, raising of mainstem of
Silver Creek to create high level of groundwater and floodplain connectivity
with wetland, replanting to establish woody wetland species to replace
mowed grasses.
SUBTOTAL 3.32 3.27 1.63
RESTORATION WETLANDS
Restoration Wetland 1 (R1) – Riparian
Restoration 0 0.21 1:1 0.21
Restoration wetland; credit proposed at 1:1. Proposed activities to include
minor grading to create connectivity to hydric soils, route overland flow into
areas to increase ponding and infiltration, and planting with target of
hardwood bottomland forest ecosystem to replace mowed grasses.
Restoration Wetland 2 (R2) – Riparian
Restoration 0 1.22 1:1 1.22
Restoration wetland; credit proposed at 1:1. Proposed activities to include
removal of less than 12” of overburden from past fill activities thought to be
associated with road construction, remeandering of UT3 through the midd le
of the proposed restoration wetland to restore hydrology, and replanting with
wetland herbaceous and hardwood bottomland forest ecosystem to replace
mowed grasses, predominantly fescue.
Restoration Wetland 3 (R3) – Riparian
Restoration 0 0.18 1:1 0.18
Restoration wetland; credit proposed at 1:1. Proposed activities to include
removal of less than 12” of overburden from past fill activities thought to be
associated pasture enhancement, plugging of drainage ditch that extends into
the area to restore hydrology (reduce hydraulic gradient), and potential to
divert some larger stream flows from UT3 into this vicinity through overland
channels that would mimic a complex floodplain with abandoned channels
and abundant roughness elements affecting floodplain flow paths.
Restoration Wetland 4 (R4) – Riparian
Restoration 0 0.62 1:1 0.62
Restoration wetland; credit proposed at 1:1. Proposed activities to include
removal of less than 12” of overburden from past fill activities thought to be
associated with channel dredging, channel restoration to include removal of
levy along mainstem creek bank to enhance floodplain access and also to
raise base flow elevation relative to floodplain elevation, and replanting with
wetland herbaceous and hardwood bottomland forest ecosystem to replace
mowed grasses (predominantly fescue).
Restoration Wetland 5 (R5) – Riparian
Restoration 0 1.53 1:1 1.53
Restoration wetland; credit proposed at 1:1. Proposed activities to include
removal of less than 12” of overburden from past fill activities thought to be
associated with pasture enhancement, removal of adjacent ditch should
reduce groundwater drawdown rate by raising the potentiometric surface in
this area, and replanting with wetland herbaceous and hardwood bottomland
forest ecosystem to replace mowed grasses.
Restoration Wetland 6 (R6) – Riparian
Restoration 0 1.54 1:1 1.54 Restoration wetland; credit proposed at 1:1. Proposed activities will include
removal of less than 12” of existing overburden thought to be placed for

pasture enhancement, removal of ditch features at the top of the wetland and
adjacent to the mainstem that are reducing ponding volumes and recharge,
raising the baseflow level and modifying the typical design cross-section of
the mainstem in this area to increase floodplain activation frequency, and
constructing minor diversions of overland flow and flow from high flow
events on UT1 into the area to further enhance hydrology. The area will be
replanted with a target hardwood bottomland forest plant community to
replace existing mowed grasses and herbaceous wetland species.
SUBTOTAL 0 5.3 5.30
CREATION WETLANDS
Creation Wetland 1 (C1) – Riparian
Creation
(3:1) 0 0.99 3:1 0.33
Creation wetland; credit proposed at 3:1. Proposed activities to include
grading of existing drainage ditch to a more natural and broad swale with a
low gradient and intermittent ponding areas. This is already a high recharge
area, but reconnection of the main stem with the floodplain will create a
significant increase in flooding to this area as well. Higher global water
tables will reduce groundwater flow out of the area. The increase in
hydrology and the grading efforts should create conditions necessary for
wetland creation. The area will be replanted with a target hardwood
bottomland forest plant community to replace existing mowed grasses and
herbaceous wetland species.
SUBTOTAL 0 0.99 0.33

Wetland Summary

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Comments
Restoration 5.30 1:1 5.30
Enhancement 3.27 2:1 1.63
Creation 0.99 3:1 0.33
TOTAL WMUs 7.26
Figure ES.1: The original mitigation plan asset map

Table ES.2.Rev: The revised mitigation plan addendum wetland asset table:
Table ES.2.Rev Upper Silver Creek Mitigation Plan Addendum: Wetland Assets
Upper Silver Creek Mitigation Plan-DMS Project #94645
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Comments
ENHANCEMENT WETLANDS
Non-Riparian
Jurisdictional Wetland 1A (JDW1A) – Non-Riparian
Enhancement
(2:1) 0.42 0.42 2:1 0.21
Existing jurisdictional wetland; 2:1 enhancement proposed to include minor
grading in areas of fill and altered drainage patterns, replanting of mowed
vegetation to include woody bottomland wetland species.
SUBTOTAL 0.42 0.42 2:1 0.21
Riparian
Jurisdictional Wetland 1B (JDW1B) – Riparian
Enhancement
(2:1) 1.01 1.01 2:1 0.51
Existing jurisdictional wetland; enhancement proposed at 2:1 to include
significant enhancements to hydrology and vegetation. UT3 will be raised to
bring hydrology within 1’ of the surface and will be routed along the
periphery of this wetland. In addition, hydrology from the mainstem will be
augmented (base flow elevation raised by 0.5’) and will be routed closer to
the wetland area. Mowed vegetation will be planted with woody bottomland
wetland species.
Jurisdictional Wetland 2 (JDW2) –Riparian
Enhancement
(2:1) 0.51 0.51 2:1 0.25
Existing jurisdictional wetland; enhancement proposed at 2:1 (typical
enhancement ratio) to include plug of existing drainage ditch which has
altered wetland hydrology, planting of woody bottomland wetland species to
replace mowed grasses, minor grading of lower part of wetland and increase
of baseflow elevation of mainstem by approximately 1.5 feet.
Jurisdictional Wetland 3 (JDW3) – Riparian
Enhancement
(2:1) 0.03 0.03 2:1 0.02
Existing jurisdictional wetland; enhancement proposed at 2:1 to include
minor grading to remove less than 12” of overburden, reduction of hydraulic
gradient by plugging existing drainage ditch and raising baseflow elevation
of mainstem (these will serve to decrease the gradient of groundwater flow
within the project area, resulting in an increased hydroperiod for adjacent
wetlands). The area will be planted with woody wetland species to replace
mowed grasses.
Jurisdictional Wetland 4 (JDW4) – Riparian
Enhancement
(2:1) 0.24 0.24 2:1 0.12
Existing jurisdictional wetland; enhancement proposed at 2:1 to include
reduction of hydraulic gradient to adjacent areas by plugging existing
drainage ditch and raising baseflow elevation of mainstem. The mainstem
will also be relocated which should increase the influence of its hydrology on
adjacent areas and decrease the gradient of groundwater flow. The area will
be planted with woody wetland species to replace mowed grasses.
Jurisdictional Wetland 5 (JDW5) – Riparian
Enhancement
(2:1) 0.81 0.81 2:1 0.40
Existing jurisdictional wetland; enhancement proposed at 2:1 to include
removal of overburden (fill) from areas where vegetation reflects the altered
soil conditions, plugging/removal of ditching in the immediate vicinity and
also upstream along the long linear ditch that parallels the stream,
enhancement of wetland hydrology as a result of Priority I stream restoration
and an increased base flow elevation, and increased storage/runoff retention
by disconnecting direct ditch connections to the main channel and increasing
ponding and recharge.
Jurisdictional Wetland 6 (JDW6) – Riparian
Enhancement
(2:1) 0.25 0.25 2:1 0.13
Existing jurisdictional wetland; enhancement proposed at 2:1 to include
diversion of additional overland flow into the area, raising of mainstem of
Silver Creek to create high level of groundwater and floodplain connectivity
with wetland, replanting to establish woody wetland species to replace
mowed grasses.
SUBTOTAL 2.85 2.85 1.43
RESTORATION WETLANDS
Non-Riparian
Restoration Wetland 1A (R1A) – Non-Riparian
Restoration 0 0.06 1:1 0.06
Restoration wetland; credit proposed at 1:1. Proposed activities to include
minor grading to create connectivity to hydric soils, route overland flow into
areas to increase ponding and infiltration, and planting with target of
hardwood bottomland forest ecosystem to replace mowed grasses.
Restoration Wetland 1B (R1B) – Non-Riparian
Restoration 0 0.15 1:1 0.15
Restoration wetland; credit proposed at 1:1. Proposed activities to include
minor grading to create connectivity to hydric soils, route overland flow into
areas to increase ponding and infiltration, and planting with target of
hardwood bottomland forest ecosystem to replace mowed grasses.
SUBTOTAL 0 0.21 1:1 0.21
Riparian
Restoration Wetland 2 (R2) – Riparian
Restoration 0 1.22 1:1 1.22
Restoration wetland; credit proposed at 1:1. Proposed activities to include
removal of less than 12” of overburden from past fill activities thought to be
associated with road construction, remeandering of UT3 through the middle
of the proposed restoration wetland to restore hydrology, and replanting with
wetland herbaceous and hardwood bottomland forest ecosystem to replace
mowed grasses, predominantly fescue.
Restoration Wetland 3 (R3) – Riparian
Restoration 0 0.18 1:1 0.18
Restoration wetland; credit proposed at 1:1. Proposed activities to include
removal of less than 12” of overburden from past fill activities thought to be
associated pasture enhancement, plugging of drainage ditch that extends into
the area to restore hydrology (reduce hydraulic gr adient), and potential to
divert some larger stream flows from UT3 into this vicinity through overland
channels that would mimic a complex floodplain with abandoned channels
and abundant roughness elements affecting floodplain flow paths.
Restoration Wetland 4 (R4) – Riparian
Restoration 0 0.44 1:1 0.44
Restoration wetland; credit proposed at 1:1. Proposed activities to include
removal of less than 12” of overburden from past fill activities thought to be
associated with channel dredging, channel restoration to include removal of
levy along mainstem creek bank to enhance floodplain access and also to
raise base flow elevation relative to floodplain elevation, and replanting with
wetland herbaceous and hardwood bottomland forest ecosystem to replace
mowed grasses (predominantly fescue).
Restoration Wetland 5 (R5) – Riparian
Restoration 0 1.29 1:1 1.29
Restoration wetland; credit proposed at 1:1. Proposed activities to include
removal of less than 12” of overburden from past fill activities thought to be
associated with pasture enhancement, removal of adjacent ditch should
reduce groundwater drawdown rate by raising the potentiometric surface in
this area, and replanting with wetland herbaceous and hardwood bottomland
forest ecosystem to replace mowed grasses.
Restoration Wetland 6 (R6) – Riparian
Restoration 0 1.54 1:1 1.54
Restoration wetland; credit proposed at 1:1. Proposed activities will include
removal of less than 12” of existing overburden thought to be placed for
pasture enhancement, removal of ditch features at the top of the wetland and
adjacent to the mainstem that are reducing ponding volumes and recharge,
raising the baseflow level and modifying the typical design cross-section of
the mainstem in this area to increase floodplain activation frequency, and
constructing minor diversions of overland flow and flow fr om high flow
events on UT1 into the area to further enhance hydrology. The area will be
replanted with a target hardwood bottomland forest plant community to
replace existing mowed grasses and herbaceous wetland species.
SUBTOTAL 0 4.67 4.67
CREATION WETLANDS
Creation Wetland 1 (C1) – Riparian
Creation
(3:1) 0 0.99 3:1 0.33
Creation wetland; credit proposed at 3:1. Proposed activities to include
grading of existing drainage ditch to a more natural and broad swale with a
low gradient and intermittent ponding areas. This is already a high recharge
area, but reconnection of the main stem with the floodplain will create a
significant increase in flooding to this area as well. Higher global water
tables will reduce groundwater flow out of the area. The increase in
hydrology and the grading efforts should create conditions necessary for
wetland creation. The area will be replanted with a target hardwood
bottomland forest plant community to replace existing mowed grasses and
herbaceous wetland species.
SUBTOTAL 0 0.99 0.33

Wetland Summary

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Comments
Restoration:
Non-Riparian 0.21 1:1 0.21
Restoration:
Riparian 4.67 1:1 4.67
Enhancement:
Non-Riparian 0.42 2:1 0.21
Enhancement:
Riparian 2.85 2:1 1.43

Figure 2: The revised mitigation plan addendum wetland asset map

Creation:
Riparian 0.99 3:1 0.33
TOTAL WMUs 6.85